Hand Tendons Flashcards

Question 1

Q

A 46-year-old man is brought to the emergency department after sustaining an injury to the dominant right wrist. Examination shows a 6-cm-diameter wound on the dorsal surface of the wrist. Significant contamination of the wound and segmental tendon loss are noted. Neurovascular status is intact. The patient is unable to extend the index, long, and ring fingers. Which of the following is the most important next step in management?
A) Immediate coverage with a free flap and delayed tendon grafting
B) Irrigation and debridement of all contaminated and nonviable tissue
C) Placement of allograft tendons and skin substitutes
D) Primary repair of tendons
E) Primary single-stage tendon grafting and coverage with a groin flap

Answer

A

B) Irrigation and debridement of all contaminated and nonviable tissue

Severely contaminated wounds, open fractures, and joint capsule lacerations require emergent and thorough irrigation and debridement. Fractures and skin loss should be treated in the initial procedure when feasible. Fractures should be fixed rigidly enough to allow early dynamic splinting or active motion. For lacerations without associated injury, the extensor tendon can be repaired emergently or in a delayed primary fashion after irrigation, debridement, and loose closure of the wound. If the repair is delayed, it should be performed within 7 days before the tendon ends retract or soften.

Question 2

Q

Within what time frame should tendon repair be performed?

Question 3

Q

Favorable vs unfavorable zones of extensor tendon injury

Answer

A

Good results: Zones I, II, IV, V

Worse results: Zones III, VI

Question 4

Q

An 18-year-old man is brought to the emergency department after sustaining a degloving injury to the dorsal aspect of the nondominant left hand in an all-terrain vehicle rollover. Physical examination shows loss of the soft tissues and the extensor tendons of the index, long, ring, and little fingers and an abnormal Allen test. Fractures of the second, third, and fourth metacarpal shafts are also present. Following serial debridements, the patient has a dorsal hand defect measuring 6 × 8 cm with obvious open fractures. Which of the following is the most appropriate management of the soft-tissue defect?
A) Anterolateral thigh free flap
B) Full-thickness skin grafting
C) Rectus abdominis muscle free flap
D) Reverse radial forearm flap
E) Split-thickness skin grafting

Answer

A

A) Anterolateral thigh free flap

Dorsal hand defects with exposed bone cannot be safely reconstructed with a split-thickness skin graft and require durable coverage. Although more durable than split-thickness skin grafts, full-thickness grafts cannot be expected to take over a large area such as this defect with exposed bone. Appropriate choices include the anterolateral thigh free flap or other perforator flaps (thoracodorsal artery perforator flap) or muscle flaps.

Local flaps such as the reverse radial forearm flap can be used in the upper extremity, although advances in microsurgery have led to a decrease in use, so as to minimize the added morbidity of the already injured extremity.

Question 5

Q

Local flap vs free flap for maimed upper extremity

Answer

A

Local flaps such as the reverse radial forearm flap can be used in the upper extremity, although advances in microsurgery have led to a decrease in use, so as to minimize the added morbidity of the already injured extremity.

Question 6

Q

Appropriate coverage for dorsal hand defects with exposed bone

Answer

A

Appropriate choices include the anterolateral thigh free flap or other perforator flaps (thoracodorsal artery perforator flap) or muscle flaps.

Question 7

Q

A 35-year-old man is brought to the emergency department after sustaining a deep laceration of his left dorsal hand. Physical examination shows a transverse 2-cm laceration over the dorsal metacarpal joint of the index finger with exposed extensor tendons. Radial nerve blockat the level of the wrist is planned before exploration. The needle should be inserted superficial to which of the following landmarks?
A) Flexor carpi radialis tendon
B) Lister tubercle
C) Radial artery
D) Second dorsal extensor compartment
E) Styloid process of the radius

Answer

A

E) Styloid process of the radius

The sensory branch of the radial nerve arises between the brachioradialis and extensor carpi radialis brevis approximately 8 cm proximal to the styloid process of the radius. It pierces the fascia approximately 5 cm (3 fingerbreadths) proximal to the radial styloid. The nerve then fans out proximal to the wrist and passes superficially to the radial styloid and first dorsal compartment.

Question 8

Q

Where does the sensory branch of the radial nerve arise?

Answer

A

The sensory branch of the radial nerve arises between the brachioradialis and extensor carpi radialis brevis approximately 8 cm proximal to the styloid process of the radius.

Question 9

Q

Anatomical course of the sensory branch of the radial nerve

Answer

A

The sensory branch of the radial nerve arises between the brachioradialis and extensor carpi radialis brevis approximately 8 cm proximal to the styloid process of the radius. It pierces the fascia approximately 5 cm (3 fingerbreadths) proximal to the radial styloid. The nerve then fans out proximal to the wrist and passes superficially to the radial styloid and first dorsal compartment.

Question 10

Q

What anatomical landmark should be used for radial nerve block at the wrist?

Answer

A

The nerve should be inserted superficial to the styloid process of the radius

Question 11

Q

The FDS tendon flexes the ____ joint

Answer

A

PIP joint

Question 12

Q

A 30-year-old man comes to the emergency department after sustaining a laceration of the palm of the left hand from a knife. He reports difficulty flexing the ring finger of the left hand. A photograph is shown. Which of the following is the most appropriate method to clinically assess the integrity of the flexor digitorum superficialis tendon?
A) Hold the distal interphalangeal joint of the ring finger in extension and ask the patient to flex
B) Hold the index, long, and little fingers in extension and ask the patient to flex
C) Hold the long, ring, and little fingers flexed atthe metacarpophalangeal (MCP) joint and ask the patient to flex
D) Hold the MCP joints of the index, long, and little fingers in flexion and ask the patient to extend
E) Hold the ring finger extended at the MCP joint and ask the patient to flex

Answer

A

B) Hold the index, long, and little fingers in extension and ask the patient to flex

The flexor digitorum superficialis (FDS) tendon flexes the proximal interphalangeal (PIP) joint. The flexor digitorum profundus (FDP) tendon can also flex the PIP joint, in addition to flexing the distal interphalangeal (DIP) joint. To confirm that the FDS tendon is flexing the PIP joint, FDP motion must be excluded.

Question 13

Q

FDS function

Answer

A

The flexor digitorum superficialis (FDS) tendon flexes the proximal interphalangeal (PIP) joint.

Question 14

Q

FDP function

Answer

A

In addition to flexing the distal interphalangeal (DIP) joint, the flexor digitorum profundus (FDP) tendon can also flex the PIP joint.

Question 15

Q

How to confirm that the FDS tendon is functioning

Answer

A

To confirm that the FDS tendon is flexing the PIP joint, FDP motion must be excluded.

Question 16

Q

A 28-year-old man comes to the office for evaluation because of restricted movement of the little finger of his right hand 3 years after sustaining a Zone II flexor tendon injury. Active flexion of the proximal interphalangeal joint is to 20 degrees; he is unable to actively flex the distal joint. Staged flexor tendon reconstruction is considered. Which of the following factors would prohibit consideration for tendon reconstruction?
A) Limited passive range of motion of the distal interphalangeal joint
B) Patient age
C) Poorly compliant patient
D) Scarred soft-tissue bed
E) Uncontrolled pain

Answer

A

C) Poorly compliant patient

Staged flexor tendon reconstruction is a challenging endeavor that should not be undertaken lightly. To reach a successful outcome, both the patient and the surgeon must make a commitment to extensive surgeries, therapy sessions, and the possibility that the outcome may not be ideal; in fact, the outcome may compromise some existing function (as in cases of secondary quadriga or infection).

Prerequisites for attempted surgical intervention include good passive range of motion of all joints involved; a healthy, well-vascularized soft-tissue bed for tendon gliding; and good patient compliance with postoperative therapy and wound care. In such a setting, staged flexor tendon reconstruction can be undertaken with a reasonably good chance of success. Patient range of motion can be controlled with therapy. With good compliance, patient age is not a factor. Uncontrolled pain can become controlled with appropriate medication and therapy

Question 17

Q

A 15-year-old boy is brought to the emergency department because he felt a “pop” followed by acute pain in his left ring finger while grabbing an opposing player’s jersey during a rugby match. Physical examination shows pain, tenderness, and swelling over the volar aspect of the finger, from the area of the distal interphalangeal joint flexor crease to the proximal interphalangeal (PIP) joint crease. The distal phalanx rests at neutral and no active flexion is possible. The patient can flex at the PIP with minimal discomfort. Which of the following is the most appropriate management?
A) End-to-end flexor tendon repair
B) Flexor tendon reinsertion
C) Open reduction and pin fixation of the middle phalanx
D) Splinting, followed in 2 weeks by range-of-motion exercises
E) Tendon transfer

Answer

A

B) Flexor tendon reinsertion

The scenario described provides a classic example of a distal flexor tendon avulsion. Because of several potential factors, the ring finger is the most common finger to present with this type of injury. The flexor digitorum profundus of the ring finger has a less robust insertion at the distal phalanx than the long finger, which is a tip-off in the vignette for this classic injury. Yet the ring finger is similarly involved in the type of hyperextension force, or resisted flexion force, which generates this injury. The little finger does not present as much with this injury either.Flexor tendon reinsertion is correct, because the indicated management is early operation and reinsertion, if possible, of the avulsed tendon. This can be accomplished in a variety of ways, but that discussion is not central to the question.

Question 18

Q

Why is the ring finger more often involved in jersey finger?

Answer

A

The flexor digitorum profundus of the ring finger has a less robust insertion at the distal phalanx than the long finger, which is a tip-off in the vignette for this classic injury. Yet the ring finger is similarly involved in the type of hyperextension force, or resisted flexion force, which generates this injury.

Question 19

Q

A 25-year-old lawyer comes to the office because of a 1-year history of limited ability to extend the right long finger at the proximal interphalangeal joint with no limitation of flexion following a jammed finger after playing basketball. X-ray study shows a normal articular surface and no evidence of fracture or foreign body. Which of the following is the most likely cause of this patient’s condition?
A) Dorsal collateral ligament contracture
B) Dorsal edema
C) Dupuytren contracture
D) Extensor adhesions
E) Flexor adhesions

Answer

A

E) Flexor adhesions

Previous injuries to a flexor tendon or canal can result in scar formation of the tendon to anadjacent structure. Other structures which can limit digital extension include volar plate contracture (including checkrein ligaments), collateral ligament contracture (true and accessory), scarring or insufficiency of the skin volar to the joint, and joint irregularity, arthrosis, or bony block.

Question 20

Q

What structures can limit extension at the PIPJ?

Answer

A

Flexor adhesions
Volar plate contracture (including checkrein ligaments)
Collateral ligament contracture (true and accessory)
Scarring or insufficiency of the skin volar to the joint
Joint irregularity
Arthrosis
Bony block.

Question 21

Q

A 24-year-old man comes to the office three months after sustaining a crush injury to the volar aspect of the right forearm during the rollover of a motor vehicle. Fasciotomies were performed when he awoke from a coma two days after the initial injury. Physical examination shows the digits flexed into the palm. Tenodesis effect without fixed contractures is present. A modified Henry fasciotomy scar is noted on the right forearm; skin coverage is otherwise excellent. No peripheral nerve injury is noted. Which of the following is the most appropriate surgical procedure to correct this deformity?
A ) Innervated free muscle transfer
B ) Muscle slide
C ) Resection of the intrinsic muscles
D ) Tendon lengthening
E ) Tendon transfers

Answer

A

D ) Tendon lengthening

The most appropriate surgical procedure for the correction of the deformity described is tendon lengthening.

The patient described would be classified as a Holden II, mild type, because his ischemia was caused by direct trauma and his muscle involvement is limited to the deep flexors at the site of theinjury. Z-plasty tendon lengthening and possible skin release and limited scarred muscle resection are sufficient.

Question 22

Q

Patients with established ischemic forearm contractures are categorized by:

Answer

A

Patients with established ischemic forearm contractures are categorized by both the Holden and Tsuge classification systems.

Question 23

Q

Holden I injuries

Answer

A

Patients with established ischemic forearm contractures:

In Holden I injuries, the arterial ischemia and venous stasis begin proximal to the forearm fascial compartment.

Question 24

Q

Holden II injuries

Answer

A

Patients with established ischemic forearm contractures:

Holden II injuries are from direct trauma, and the ischemia begins at the site of the injury.

Question 25

Q

Tsuge classification

Answer

A

Patients with established ischemic forearm contractures:

The Tsuge classification defines the extent of muscle involvement as mild, moderate, or severe.

Question 26

Q

Patients with established ischemic forearm contractures: Innervated free muscle transfers

Answer

A

Innervated free muscle transfers are reserved for Holden I or II, severe type, injuries. Often with nerve grafting in an attempt to establish protective distal sensation and other procedures, innervated free muscle transfers are utilized to provide both function and coverage in these patients with complete loss of muscle function after ischemic injury.

Question 27

Q

Patients with established ischemic forearm contractures: Muscle slide techniques

Answer

A

Muscle slide techniques are reserved for patients with Holden I, moderate injuries. These patients have ischemic changes affecting the entire muscle belly. Some of the muscles’ contractile units should be intact. Combined with other procedures, the muscle slide permits a reduction of the distal contractures while preserving the muscle’s residual contractile capabilities.

Question 28

Q

Patients with established ischemic forearm contractures: Resection of the dorsal intrinsic muscles

Answer

A

Resection of the dorsal intrinsic muscles and part of the adductor pollicis muscle is reserved for patients with ischemic contracture of the intrinsic muscles. Intrinsic ischemic contractures may accompany any ischemic Volkmann contracture; this will often present as the hand assuming the intrinsic-plus position following reconstruction of the extrinsic musculature.

Question 29

Q

Patients with established ischemic forearm contractures: Tendon transfers

Answer

A

Tendon transfers are used for patients with Holden II, moderate type, injuries. Proximal muscle slides are not usually performed because detachment of these healthy muscles will potentially diminish their functional capacity. Combined with other procedures, tendon transfers are used to augment any residual existing muscle function.

Question 30

Q

Patients with established ischemic forearm contractures: Tendon lengthening

Answer

A

Reserved for Holden II, mild type. Z-plasty tendon lengthening and possible skin release and limited scarred muscle resection are sufficient.

Question 31

Q

A 46-year-old man comes to the emergency department because he has pain in the index finger after falling on his outstretched right hand. He notes that the pain began immediately after the fall. Instability on isolated index to thumb key-pinch testing is noted. Radiographs show no obvious pathology. An injury to which of the following structuresis most likely?
A ) First dorsal interosseous insertion
B ) Lateral band of the extensor hood
C ) Lumbrical insertion
D ) Radial collateral ligament
E ) Volar plate

Answer

A

D ) Radial collateral ligament

Isolated injury to the radial collateral ligament of the index finger occurs with forced ulnar deviation at the metacarpophalangeal (MCP) joint. It can also occur in conjunction with injury to all of the structures surrounding the joint. In isolation, the findings of a complete tear of the ligament will be that of a flail joint. Attempted pinch will result in pain and ulnar deviation. MRI is needed for confirmation. solated injury to the lumbrical will not be demonstrable on examination, while an injury to the volar plate by itself would not cause instability on key-pinch testing. Injury to the insertion tendon of the first dorsal interosseous muscle will cause a weak pinch, but the joint will not be unstable to radial pressure. Finally, the extensor mechanism does not contribute to the stability of the MCPJ

Question 32

Q

How does injury to the radial collateral ligament of the index finger occur?

Answer

A

Isolated injury to the radial collateral ligament of the index finger occurs with forced ulnar deviation at the metacarpophalangeal (MCP) joint. It can also occur in conjunction with injury to all of the structures surrounding the joint.

Question 33

Q

Clinical presentation following injury of the radial collateral ligament of the index finger

Answer

A

In isolation, the findings of a complete tear of the ligament will be that of a flail joint. Attempted pinch will result in pain and ulnar deviation.

Question 34

Q

A 34-year-old woman who is a concert pianist is brought to the emergency department because of a laceration on the volar aspect of the right index finger at the mid-proximal phalanx caused by a broken vase. Operative exploration shows complete laceration of the radial digital nerve and the profundus and superficialis tendons in the flexor tendon sheath. Which of the following is the most effective management of the flexor tendon injury?
A ) Excision of the superficialis tendon; repair of the profundus tendon; early active-motion protocol
B ) Excision of the superficialis tendon; repair of the profundus tendon; immobilization for three weeks
C ) Repair of the profundus and superficialis tendons; early passive-motion protocol
D ) Repair of the profundus and superficialis tendons; immobilization for three weeks

Answer

A

C ) Repair of the profundus and superficialis tendons; early passive-motion protocol

The most effective management is profundus and superficialis tendon repair with early passive-motion protocol. Repairing the superficialis tendon not only improves strength and function but also has been shown to increase circulation to the tendon repairs.

Question 35

Q

Early passive and active range of motion protocols

Answer

A

Many studieshave shown the strength and adhesion-prevention benefits of early passive-motion protocols. Some studies have advocated early flexion active-motion protocols, but none have found the results superior to the early passive-motion protocols.

Question 36

Q

Strength of tendon repair is proportional to:

Answer

A

Many studies have shown that a direct correlation exists between the strength of the tendon repair and the number of core sutures used across the repair (strength is proportional to the number of sutures).

Question 37

Q

A 35-year-old man is brought to the emergency department four hours after sustaining an injury to the dominant right hand when he fell while skiing. He reports pain in the thumb. Examination shows swelling and no palpable mass on the ulnar aspect of the metacarpophalangeal (MCP) joint of the thumb. Application of radial stress to the joint shows 5 degrees of laxity; stress on the opposite thumb shows no laxity. Plain-film radiographs show no abnormalities. Which of the following is the most appropriate management?
(A)Arthroscopic reduction
(B)Immobilization of the thumb in a spica cast
(C)Movement and increased range of motion of the thumb as tolerated
(D)Open suture repair of the ulnar collateral ligament
(E)Percutaneous pin fixation of the joint

Answer

A

(B)Immobilization of the thumb in a spica cast

The patient described has sustained an injury to the ulnar collateral ligament (UCL) of the MCP joint of his thumb. To select the appropriate therapy, the extent of the injury must be determined (ie, partial versus complete disruption of the UCL). In the patient described, 5 degrees of thumb MCP joint laxity compared to the opposite side indicates that he has sustained a partial tear of his UCL. It is generally accepted that incomplete tears may be treated successfully with immobilization; complete tears require operative treatment. A thumb spica cast provides adequate immobilization to allow healing of a partial tear of this patient’s UCL.

Question 38

Q

Clinical presentation of complete ulnar collateral ligament injury of the thumb

Answer

A

A thumb MCP joint with greater than 30 degrees of laxity, or greater than a 15-degree differential in laxity compared to the contralateral side, demonstrates clinical evidence of a complete disruption of the UCL.

Question 39

Q

Why would a completely immobilized complete tear UCL of the thumb MCP not heal?

Answer

A

With a complete tear of the UCL, a Stener lesion may result whereby the adductor aponeurosis interposes itself between the ends of the completely disrupted UCL, thus preventing ligamentous healing despite prolonged immobilization.

Question 40

Q

Treatment of a Stener lesion of the thumb MCP UCL

Answer

A

Complete tear of the UCL:
With a complete tear of the UCL, a Stener lesion may result whereby the adductor aponeurosis interposes itself between the ends of the completely disrupted UCL, thus preventing ligamentous healing despite prolonged immobilization. Both open suture repair of the UCL and arthroscopic reduction without suture repair of the UCL have been described as operative treatment modalities for Stener lesions.

Question 41

Q

How should a splint be fashioned for a complete tear of the UCL of the thumb MCP?

Answer

A

The splint could be fashioned to leave the interphalangeal (IP) joint free and allow active range of motion in the IP joint to prevent adherence of the extensor tendon to the injured MCP joint capsule

Question 42

Q

A 32-year-old man who works as a carpenter comes to the office for follow-up examination seven days after sustaining a 2-cm laceration to the dorsum of the left thumb proximal to the interphalangeal joint while using a knife. In the emergency department, the laceration was sutured, and the thumb was immobilized with a splint. On physical examination, the wound is clean. No infection is noted. Weak extension of the interphalangeal joint is noted. The patient cannot extend the thumb off the tabletop. Laceration of which of the following tendons is most likely?
(A)Abductor pollicis longus
(B)Extensor carpi radialis brevis
(C)Extensor carpi radialis longus
(D)Extensor pollicis brevis
(E)Extensor pollicis longus

Answer

A

(E)Extensor pollicis longus

The patient described has an injury to the extensor pollicis longus (EPL) tendon, which can be difficult to diagnose in the emergency department.

Often, a patient will have weak active extension at the interphalangeal joint. The thumb extensor mechanism receives fibers from the abductor pollicis brevis, adductor pollicis, the ulnar head of the flexor pollicis brevis, and the EPL. If the EPL is lacerated, there may be weak extension at the interphalangeal joint; however, the thumb cannot be actively lifted off a tabletop. The extensor pollicis brevis, abductor pollicis longus, extensor carpi radialis longus, and extensor carpi radialis brevis do not contribute to the extension of the thumb off a tabletop.

Question 43

Q

The thumb extensor mechanism receives vibes from:

Answer

A

Abductor pollicis brevis,
Adductor pollicis
Ulnar head of the flexor pollicis brevis
Extensor pollicis longus

Question 44

Q

What muscle(s) contributes to lifting the thumb off a table top?

Answer

A

The EPL is the only muscle

If lacerated, there may be weak extension at the thumb IP.

Question 45

Q

A 42-year-old man comes to the office because he has a three-month history of significantly decreased grip strength of the dominant left hand since undergoing fusion of the proximal interphalangeal (PIP) joint of the long finger for traumatic arthritis of the joint. Fusion was performed with the PIP joint held in approximately 30 degrees of flexion. Radiographs show a well-healed fusion site. Physical examination shows a 25% decrease in grip strength of the left hand compared with the nondominant uninjured hand. Full active range of motion of the distal interphalangeal and metacarpophalangeal joints of the injured finger is noted. Which of the following is the most likely cause of these findings?
(A)Disuse atrophy
(B)Extrinsic tightness
(C)Flexor tendon injury
(D)Intrinsic tightness
(E)Quadriga effect

Answer

A

(E)Quadriga effect

The patient described is experiencing weakness caused by the quadriga effect imposed by the fusion of the PIP joint of the long finger.

Question 46

Q

What is a quadriga?

Answer

A

A quadriga (from the Latin quadria[four] and jungere[to yoke]) is a four-horse chariot that was raced in the Olympics and other sacred games.

Question 47

Q

PIP fusion of the index finger

Answer

A

PIP fusion is often well tolerated in the index finger because that finger’s relatively independent profundus function does not impose a significant quadriga effect on the other fingers during power grasp.

Question 48

Q

PIP fusion of the long finger

Answer

A

IP fusion of the long finger has been shown to decrease the excursion of all profundus tendons, reducing grip strength.

Question 49

Q

PIP vs DIP vs MCP fusion on the profundus

Answer

A

PIP fusion restricts profundus excursion to a greater extent than distal interphalangeal (DIP) or metacarpophalangeal (MCP) joint fusion.

Question 50

Q

Limitation of PIP joint fusion before grip strength decreases

Answer

A

A significant decrease in grip strength occurs when the PIP joints of the index and small fingers are fixed at less than 45 degrees and when the long and ring fingers are fused in a position of less than 60 degrees of flexion.

Question 51

Q

A 36-year-old man comes to the office for follow-up examination four months after undergoing revision amputation at the distal interphalangeal joint of the left long finger to repair a partial traumatic amputation injury. Since undergoing the procedure, the patient has had difficulty making a fist. Physical examination shows extension of the proximal interphalangeal (PIP) joint when the metacarpophalangeal (MCP) joint is actively flexed. The patient has full active and passive range of motion of the PIP joint when the MCP joint is extended. Radiographs show no abnormalities. Which of the following is the most appropriate next step in management?
(A)Dynamic flexion splinting
(B)Fusion of the PIP joint
(C)Injection of a corticosteroid into the area of the A1 pulley
(D)Surgical release of the lumbrical
(E)Tenolysis

Answer

A

(D)Surgical release of the lumbrical

The patient described has a lumbrical plus deformity. This deformity occurs following amputation when proximal migration of the profundus tendon results in contracture of the lumbrical muscle. This contracture can result in tightness of the lumbricals, which produces paradoxical extension of the PIP joint during active flexion of the MCP joint. The lumbrical muscle is a component of the intrinsic extensor mechanism, which is responsible for MCP flexion and PIP extension. The lumbrical plus deformity is treated most appropriately by division of the lumbrical tendon.

Question 52

Q

Lumbrical plus deformity: When does it occur

Answer

A

Occurs following amputation when proximal migration of the profundus tendon results in contracture of the lumbrical muscle.

Question 53

Q

Clinical manifestations of a lumbrical plus deformity

Answer

A

This contracture can result in tightness of the lumbricals, which produces paradoxical extension of the PIP joint during active flexion of the MCP joint.

Question 54

Q

The extensor mechanism is responsible for what movements (of the hand)?

Answer

A

MCP flexion and PIP extension.

Question 55

Q

Treatment of lumbrical plus deformity

Answer

A

Division of the lumbrical tendon

Question 56

Q

A 25-year-old woman comes to the office for consultation regarding an injury to the left thumb (shown). During surgical repair of this injury, which of the following is the sequence in which anatomic structures will be encountered?
(A) Abductor pollicis, flexor pollicis longus, volar plate
(B) First dorsal interosseous, oblique pulley, volar plate
(C) Junctura tendineum, extensor pollicis longus, collateral ligament
(D) Sagittal bands, adductor aponeurosis, collateral ligament
(E) Skin, ulnar collateral ligament, volar plate

Answer

A

(D) Sagittal bands, adductor aponeurosis, collateral ligament

This patient has an ulnar collateral ligament injury of the thumb metacarpophalangeal (MP) joint. Although the indications for surgical repair are controversial, the pertinent anatomy is consistent. After the skin and subcutaneous tissue are divided, the sagittal bands are encountered. The sagittal bands stabilize the extensor pollicis longus over the MP joints of the thumb and travel from the lateral aspects of the tendon towards the flexor digital sheath. Repair of this structure is important to prevent subluxation of the tendon with thumb motion.

Question 57

Q

Sequential anatomy encountered during repair of the ulnar collateral ligament of the thumb

Answer

A

After the skin and subcutaneous tissue are divided, the sagittal bands are encountered.
The adductor for aponeurosis is readily visible under the sagittal bands.
Once the adductor aponeurosis is divided, the ulnar collateral ligament is readily visible and amenable to repair.

Question 58

Q

Sagittal bands (MP joint of the thumb)

Answer

A

The sagittal bands stabilize the extensor pollicis longus over the MP joints of the thumb and travel from the lateral aspects of the tendon towards the flexor digital sheath.

Question 59

Q

Why is it important to repair the sagittal bands during repair of a thumb UCL tear?

Answer

A

Repair of this structure is important to prevent subluxation of the tendon with thumb motion.

Question 60

Q

A 42-year-old man is brought to the emergency department after he sustained major injuries when he fell from a ladder. In addition to abdominal trauma, he sustained lacerations of the flexor carpi ulnaris tendons, ulnar artery, ulnar nerve, flexor digitorum profundus tendons, flexor digitorum superficialis tendons, flexor pollicis longus muscles, palmaris longus tendon, median nerve, radial artery, and flexor carpi radialis tendon of the right arm. During emergent exploratory laparotomy with general anesthesia, an upper arm tourniquet is inflated to 250 mmHg. Two hours later, when the laparotomy is completed, the tourniquet is still in place and the patient is asleep. Which of the following is the most appropriate management of the injuries to this patient’s hand?
(A) Release the tourniquet, close the skin, and repair the severed structures electively
(B) Release the tourniquet and repair the severed structures immediately
(C) Leave the tourniquet in place and repair the severed structures immediately
(D) Release the tourniquet for five minutes, reinflate the tourniquet, and repair the severed structures
(E) Release the tourniquet for 20 minutes, reinflate the tourniquet, and repair the severed structures

Answer

A

(E) Release the tourniquet for 20 minutes, reinflate the tourniquet, and repair the severed structures

Continuation of the tourniquet would be dangerous to this patient; the upper limit of time for tourniquet use in the upper extremity is most frequently defined as two hours, after which muscle and nerve damage begins. Performing the surgery without tourniquet control is an option but is not the best option in a true spaghetti-like wrist, for which a bloodless field is best for meticulous preparation and identification of structures. Of the options listed, the best choice is to release the tourniquet for 20 minutes (5 minutes for every 30 minutes the tourniquet was in use) and to finish the case immediately.

Question 61

Q

Max amount of tourniquet time for the upper extremity

Answer

A

120 minutes

Question 62

Q

How long of a tourniquet break should be given if it must be reinflated, for the upper extremity?

Answer

A

5 minutes for every 30 minutes the tourniquet was in use

Question 63

Q

A 28-year-old woman comes to the office for follow-up examination after six weeks of splinting to correct a closed injury without fracture of the right index finger (mallet finger). Despite instructions to wear the splint at all times, the patient says she has been taking it off when she showers and when she types at work because it gets in the way. Which of the following is the most appropriate next step in management?
(A) Splinting for an additional six weeks
(B) Transarticular fixation with Kirschner wires
(C) Central slip tenotomy
(D) Open repair with direct suturing of the terminal tendon
(E) Fusion of the distal interphalangeal joint

Answer

A

(B) Transarticular fixation with Kirschner wires

This patient has a mallet finger deformity. No fracture was involved; therefore, it is considered a Type I mallet injury. Patients are sometimes noncompliant or not well instructed regarding how the splint is to be used. Both the Fowler tenotomy and open repair should be reserved for chronic cases of mallet finger. In fact, open repair with direct suture of the terminal tendon has shown poor results. Fusion of the distal interphalangeal joint is an extreme method of treating this condition and would not be indicated at this time. An additional six-week period of splinting would be appropriate in a compliant patient. One author has shown that mallet fingers that remain untreated for up to 12 weeks can be treated conservatively with six weeks of splinting. However, a noncompliant patient would benefit from transarticular fixation with Kirschner wires, which would be more difficult to manipulate versus splinting alone.

Question 64

Q

Noncompliant patient and Type I mallet injury

Answer

A

Kirschner wires if they won’t wear their splint - more difficult to manipulate

Answer 64

A

Clinical presentation + no fracture on xray

Answer 65

A

Both the Fowler tenotomy and open repair should be reserved for chronic cases of mallet finger.

Answer 66

A

Both the Fowler tenotomy and open repair should be reserved for chronic cases of mallet finger. (Open repair has shown good results)

Answer 67

A

(E) Tightness of the ligament of Landsmeer

Answer 68

A

The oblique retinacular ligament of Landsmeer passes volar to the axis of rotation of the proximal interphalangeal (PIP) joint, and when it is involved in a fibrotic process, it may produce hyperextension of the distal interphalangeal (DIP) joint. Tightness of this ligament can result in contractural deformity resulting in a boutonnière deformity.

Answer 69

A

Inadequate checkrein release would result in persistent flexion deformity at the PIP joint

Answer 70

A

(D) Sagittal bands, adductor aponeurosis, collateral ligament

Answer 71

A

The volar plate may be injured in a gamekeeper’s type of injury and should be assessed. A clue to a significant volar plate injury requiring repair is volar subluxation of the proximal phalanx in relation to the metacarpal.

Answer 72

A

(E) Release the tourniquet for 20 minutes, reinflate the tourniquet, and repair the severed structures

Release the tourniquet for 20 minutes (5 minutes for every 30 minutes the tourniquet was in use) and to finish the case immediately.

Answer 73

A

(A) A1 pulley release

The first step in management of this deformity is A1 pulley release. The patient has a congenital trigger thumb, the most common cause of congenital thumb flexion deformity. The flexed position of the thumb can also be seen in patients with congenital clasped thumb, absent or aberrant extensor tendons, arthrogryposis, and spasticity. Patients with congenital trigger thumb commonly have thickening of the tendon, referred to as “Notta’s node.” In patients younger than age 3 years, the spontaneous resolution rate is 30%. Splinting and observation are options when the condition is diagnosed early, but most patients require surgery. During release of the pulley,no attempt is made to excise or reduce the nodule in the tendon. Aspiration is not appropriate for the nodule in the flexor tendon. `

Answer 74

A

Release of A1 pulley

Answer 75

A

Congenital trigger thumb

Answer 76

A

Patients with congenital trigger thumb commonly have thickening of the tendon, referred to as “Notta’s node.”

Answer 77

A

In patients younger than age 3 years, the spontaneous resolution rate is 30%.

Answer 78

A

During release of the pulley,no attempt is made to excise or reduce the nodule in the tendon.

Answer 79

A

(A) Flexor digitorum profundus tendon in Zone I

This patient has sustained a “jersey finger” injury. The digital cascade isdisrupted because there is no flexion force at the distal phalanx of the ring finger. In this patient, the flexor digitorum profundus tendon became avulsed from the distal phalanx (Zone I) when the patient attempted to actively flex the distal interphalangeal joint with the finger in forced extension

Answer 80

A

(B) Adductor aponeurosis

This patient has a classic Stener lesion, in which the adductor aponeurosis becomes interposed between the ruptured ulnar collateral ligament and the base of the proximal phalanx. This lesion cannot heal spontaneously because reattachment of the ulnar collateral ligament to the proximal phalanx is blocked by the interposed tendon.

Answer 81

A

The adductor aponeurosis becomes interposed between the ruptured ulnar collateral ligament and the base of the proximal phalanx. This lesion cannot heal spontaneously because reattachment of the ulnar collateral ligament to the proximal phalanx is blocked by the interposed tendon.

Answer 82

A

Without surgical correction, the patient will have painful instability to radial stress of the thumb metacarpophalangeal joint.

Answer 83

A

(D) Flexor digitorum superficialis to flexor digitorum profundus

Because this 12-year-old boy with spastic cerebral palsy has both poor cognition and sensibility, improvement of hygiene will be the primary goal of any surgical procedure. Therefore, transfer of the flexor digitorum superficialis tendon to the flexor digitorum profundus tendon is recommended to eliminate the clenched fist deformity and relieve the maceration and disintegration of skin that is typically associated with this deformity. This tendon transfer lengthens yet weakens the finger flexors.

Transferring the flexor carpi ulnaris to the flexor digitorum profundus will only increase the flexion force and aggravate the deformity. Transfer of the flexor digitorum profundus to the extensor digitorum communis will not resolve the clenched fingers. In patients who have a deformity of this severity, arthrodesis of the wrist is recommended instead of tendon transfers to the wrist extensors.

Answer 84

A

Important elements included in the preoperative testing of patients with cerebral palsy are evaluation of cognition, hand placement, and sensibility. In patients who fail to meet the minimum criteria in these areas, the primary goal of surgery is improvement of hygiene and not necessarily of hand function.

Answer 85

A

Functional improvement following surgery can only be expected in those children who can successfully discriminate texture, identify objects, or exhibit graphesthesia (test dependent on age), or those who have moving two-point discrimination of less than 10 mm.

Answer 86

A

(A) Extensor tendon

This 18-year-old college student has sustained a volar dislocation of the proximal interphalangeal (PIP) joint.

In volar dislocations, which are far less common than dorsal dislocations, the extensor tendon is torn by the distal condyle of the proximal phalanx, as shown in the intraoperative photograph above. If the condyle has pushed through the extensor tendon, the tendon may tighten and act as a sling to prevent reduction of the dislocation.

Answer 87

A

In volar dislocations, which are far less common than dorsal dislocations, the extensor tendon is torn by the distal condyle of the proximal phalanx, as shown in the intraoperative photograph above. If the condyle has pushed through the extensor tendon, the tendon may tighten and act as a sling to prevent reduction of the dislocation.

Answer 88

A

In volar dislocations, which are far less common than dorsal dislocations, the extensor tendon is torn by the distal condyle of the proximal phalanx, as shown in the intraoperative photograph above. If the condyle has pushed through the extensor tendon, the tendon may tighten and act as a sling to prevent reduction of the dislocation.

Although some physicians may be able to perform closed reduction, operative exploration and repair are recommended because of the possible injury to the extensor tendon. Unsuccessful closed reduction is an absolute indication for operative exploration, as repeat attempts at manipulation will only worsen edema and may contribute to injury. In addition, volar dislocations can be associated with complete avulsion of thecentral slip, requiring repair

Answer 89

A

(E) Zone 5

Flexor tendon injuries in zone 5 have the best prognosis following repair. This zone, one of five in the flexor tendon system, lies proximal to the carpal tunnel. The generous space found proximal to the wrist allows for better tendon gliding following repair

Answer 90

A

Flexor tendon injuries in zone 5 have the best prognosis following repair. This zone, one of five in the flexor tendon system, lies proximal to the carpal tunnel. The generous space found proximal to the wrist allows for better tendon gliding following repair

Answer 91

A

Zone 2 is an especially tight region that contains both flexor tendons within the fibro-osseous tunnel. There is an increased risk for development of adhesions when flexor tendons are repaired in this zone.

Answer 92

A

(B) Release of the central slips

The most appropriate management of the extensor tendon tightness seen in this patient is release of the central slips. Central slip releases can be performed under local anesthesia to immediately improve flexion of the proximal interphalangeal (PIP) joint. This simple maneuver may eliminate the need for extensive soft-tissue reconstruction as long as the scar and tendon contractures are located on the dorsal aspect of the hand and the lateral bands, which supply extensor power to the PIP and distal interphalangeal (DIP) joints, are intact. The risk for subluxation of the intact lateral bands and subsequent development of a boutonierre deformity is minimal.

Answer 93

A

(B) Division of the lumbrical tendon

The most appropriate management at this time is division of the lumbrical tendon.This patient has a lumbrical-plus deformity, which occurs following sectioning of the flexor digitorum profundus (FDP) tendon. In patients with this deformity, the independent FDP tendon and lumbrical muscle migrate proximally. With flexion, tension is exerted by the lumbrical via the radial lateral band. During attempted flexion of the digit, this tension transmitted through the radial lateral band results in paradoxical extension of the proximal interphalangeal (PIP) joint.

Answer 94

A

The lumbrical tendons originate from the FDP tendon and insert into the radial lateral band. These tendons pass palmar to the deep transverse inter metacarpal ligament.

Answer 95

A

(C) Intersection syndrome

This patient has findings consistent with intersection syndrome, or tenosynovitis of the second dorsal compartment that involves the extensor carpi radialis longus and brevis tendons at their intersection near the first extensor compartment. Patients have pain and swelling approximately 4 cm proximal to the wrist, at the point where the extensor pollicis brevis and abductor pollicis longus tendons cross the common radial wrist extensors. Erythema and crepitus are also associated. Symptoms are exacerbated with prolonged wrist motion

Answer 96

A

Intersection syndrome: tenosynovitis of the second dorsal compartment that involves the extensor carpi radialis longus and brevis tendons at their intersection near the first extensor compartment.

Answer 97

A

Patients have pain and swelling approximately 4 cm proximal to the wrist, at the point where the extensor pollicis brevis and abductor pollicis longus tendons cross the common radial wrist extensors. Erythema and crepitus are also associated. Symptoms are exacerbated with prolonged wrist motion

Answer 98

A

Appropriate management includes splinting of the wrist in extension and injection of a corticosteroid. Surgical procedures, such as release of the second dorsal compartment and/or synovectomy at the intersection point, may be required in those patients whose symptoms do not improve with conservative measures

Answer 99

A

Patients with carpometacarpal joint arthritis have pain at the base of the metacarpal of the thumb. Pain is reproduced on a carpometacarpal grind test or axial compression test.

Answer 100

A

De Quervain tenosynovitis is stenosing tenosynovitis of the first dorsal compartment; the extensor pollicis brevis and abductor pollicis longus tendons are affected.

Answer 101

A

This condition is characterized by localized pain, swelling, and tenderness 1 to 2 cm proximal to the radial styloid. Affected patients have pain on ulnar deviation of the wrist with the thumb clasped in the palm (Finkelstein test)

Answer 102

A

Pain on ulnar deviation of the wrist with the thumb clasped in the palm (Finkelstein test)

Answer 103

A

Pain is commonly elicited over the scapholunate interval. Scapholunate instability may also be present. Radiographs may show an increased scapholunate interval.

Answer 104

A

In Wartenberg syndrome, the superficial sensory branch of the radial nerve is entrapped between the brachioradialis and extensor carpi radialis longus tendons.

Answer 105

A

Pain, numbness, and tingling at the dorsoradial aspect of the wrist are characteristic, and symptoms are often exacerbated when the patient wears compressive jewelry, such as a wristwatch

Answer 106

A

(B) Repeat operative exploration and repair

The most appropriate next step in management is repeat operative exploration and repair. This patient has most likely ruptured the flexor tendon. This typically occurs four to six weeks after initial repair and is most commonly caused by excessive grip force or significant devascularization of the tendon.

Answer 107

A

Four to six weeks after initial repair

Answer 108

A

Most commonly caused by excessive grip force or significant devascularization of the tendon.

Answer 109

A

Staged reconstruction with insertion of a silicone rod and/or delayed tendon grafting is appropriate following tendon rupture if passive range of motion of the finger is significantly limited or there is an insufficient quantity of flexor tendon sheath.

Answer 110

A

Tenolysis is indicated in patients who have tendon adherence or scarring following tendon repair. This procedure is typically delayed for four to six months following the initial repair, and is most effect if the repair is intact and full passive range of motion is maintained.

Answer 111

A

(D) Operative release of the A1 pulley

In this child who has a fixed flexion deformity of the thumb, most likely resulting from congenital triggering, the most appropriate management is operative release of the A1 pulley. Trigger thumb is an isolated congenital deformity that is thought to occur in 0.05% of live births; 25% to 33% of patients have bilateral findings.

Answer 112

A

Proliferation of synovial fluid within the tendon.

Answer 113

A

25% to 33% of patients have bilateral findings.

Answer 114

A

Because the thumb is often minimally flexed in infants, the deformity is not typically diagnosed until age 6 months

Answer 115

A

n children with the clasp thumb deformity, there is absence of the extensor pollicis brevis and/or extensor pollicis longus tendons.

Answer 116

A

This deformity is characterized by extreme flexion of the metacarpophalangeal joint and adduction of the thumb into the palm.

Answer 117

A

(C) Adductor pollicis

The palpable mass on the ulnar aspect of the metacarpal head is a Stener lesion, which is formed by interposition of the fascia of the adductor pollicis between the torn ulnar collateral ligament and the metacarpophalangeal (MP) joint. The proximal stump of the ulnar collateral ligament lies superficial and proximal to the fascia of the adductor pollicis. Interposition of the adductor pollicis prevents healing of the ligament. Operative repair is indicated in patients with Stener lesions.

Answer 118

A

(B) Immediate early active flexion

In patients with zone II flexor tendon injuries, outcome is most dependent on the repair technique and rehabilitation protocol used.

Answer 119

A

Suture techniques that employ locking loops or multiple strands have been shown to be stronger and to provide a better, longer lasting repair than the standard, two-strand modified Kessler technique.

Answer 120

A

In general, an immediate, graded early active flexion program has been shown to result in greater total active motion than early passive flexion and/or late motion programs.

Answer 121

A

History of smoking has been shown to correlate with poorer outcomes regardless of the method of rehabilitation.

Answer 122

A

(C) Quadriga effect

This patient’s deformity is most likely caused by the quadriga effect, which occurs as a result of excess distal pull on one profundus tendon. Because the flexor profundus tendons share a common muscle belly, any excess pull on one tendon will decrease the force and amplitude of all of the tendons. Quadriga can occur secondary to amputations in which the flexor digitorum profundus (FDP) tendon is attached to the extensor tendon or following grafting of excessively short tendons or advancement of the FDP tendon in patients with zone I injuries. Flexor tendon adhesions can occur following injury or prolonged immobilization. Decreased flexion of the affected digit only is a characteristic finding.

Answer 123

A

(C) 150 Degrees

The total active range of motion of the index finger in this patient is 150 degrees. Total active motion (TAM), which is used to measure range of motion of the fingers, is the sum total of active motion of the metacarpophalangeal (MP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, subtracting any extension deficit of the joints.

Answer 124

A

The total active range of motion of the index finger in this patient is 150 degrees. Total active motion (TAM), which is used to measure range of motion of the fingers, is the sum total of active motion of the metacarpophalangeal (MP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, subtracting any extension deficit of the joints.

Answer 125

A

(B) Extension splinting of the PIP joint

The most appropriate management is splinting of the PIP joint in extension; this can be performed successfully as late as six weeks after initial injury. The DIP joint should be left unencumbered to allow motion, which will result in dorsal migration of the lateral bands and reestablish the normal relationship of the tendinous structures within the finger:

This patient has a boutonniere deformity, which results from disruption of the central slip of the extensor tendon at the PIP joint with concomitant volar migration of the lateral bands. This volar migration may not be seen until 10 to 21 days after injury. Patients with boutonniere deformities have persistent flexion of the PIP joint resulting from loss of the central slip and the unopposed forces of the flexor digitorum superficialis tendon. The transverse retinacular ligaments become stretched, and the volarly migrated lateral bands exert direct pull on the DIP joint. This leads to the characteristic findings of hypertension of the DIP joint and worsening flexion of the PIP joint.

Answer 126

A

Disruption of the central slip of the extensor tendon at the PIP joint with concomitant volar migration of the lateral bands.

Answer 127

A

Disruption of the central slip of the extensor tendon at the PIP joint with concomitant volar migration of the lateral bands:

This volar migration may not be seen until 10 to 21 days after injury.

Answer 128

A

Persistent flexion of the PIP joint Hypertension of the DIP joint

Answer 129

A

Persistent flexion of the PIP joint: Loss of the central slip and unopposed forces of the flexor digitorum superficialis tendon.

Hypertension of the DIP joint and worsening flexion of the PIP joint: The transverse retinacular ligaments become stretched, and the volarly migrated lateral bands exert direct pull on the DIP joint.

Answer 130

A

The most appropriate management is splinting of the PIP joint in extension; this can be performed successfully as late as six weeks after initial injury. The DIP joint should be left unencumbered to allow motion, which will result in dorsal migration of the lateral bands and reestablish the normal relationship of the tendinous structures within the finger.

Answer 131

A

(A) Decortication

Patients who have pain disproportionate to the level of injury should be evaluated to exclude a potential diagnosis of osteomyelitis, which in those without open fractures can result from local infection or hematogenous spread. In this patient, the MRI shows an abnormal signal in the proximal phalanx, which is consistent with osteomyelitis.

Neurectomy is used for repair of neuromas, which manifest as a localized positive Tinel’s sign, while neuroplasty would be theprocedure of choice in a patient who has an entrapped nerve. Tendon repair is not required because the previous repair is still intact, as shown in the photograph and MRI. Tenolysis will improve the limited tendon excursion seen in patients who have tendon adhesions or scarring

In cases such as this one, appropriate management includes surgical exploration, decortication to decompress the infected bone, and removal of all involved bone. Antibiotics should be administered intravenously following this procedure, and bone grafting should be performed at a later date.

Answer 132

A

Although Staphylococcus aureus is the most likely causal organism, Mycobacterium marinum and anaerobic organisms can also be associated.

Answer 133

A

In cases such as this one, appropriate management includes surgical exploration, decortication to decompress the infected bone, and removal of all involved bone. Antibiotics should be administered intravenously following this procedure, and bone grafting should be performed at a later date.

Answer 134

A

Decortication should be performed to decompress the infected bone, followed by removal of all involved bone.

Answer 135

A

(D) Repair of the extensor pollicis longus tendon

In this patient who has a functional deficit involving the interphalangeal (IP) joint of the thumb after sustaining a zone V laceration of the extensor pollicis longus (EPL) tendon, repair of the tendon will provide the best functional outcome. The EPL tendon facilitates hyperextension of the IP joint of the thumb, which is no longer possible in this patient. In contrast, the mechanism of action of the intrinsic muscles, via their contributions to the extensor tendon mechanism, allows the patient to extend the IP joint of the thumb only to a neutral position.

Answer 136

A

The mechanism of action of the intrinsic muscles, via their contributions to the extensor tendon mechanism, allows the patient to extend the IP joint of the thumb only to a neutral position.

Answer 137

A

(E) Palmaris longus (Camitz)

In this 75-year-old woman who has severe carpal tunnel syndrome, the palmaris longus tendon should be transferred to improve thumb motion. Patients with severe carpal tunnel syndrome are often unable to fully clear the thumb from the palm. The Camitz abductorplasty can be used to augment the abductor pollicis brevis tendon with the palmaris longus.

Answer 138

A

In contrast to an abductorpluasty, which improves thumb motion, a true opponensplasty restores thumb-finger opposition.

Answer 139

A

The Bunnell opponensplasty involves transfer of the flexor digitorum superficialis tendon of the ring finger,

Answer 140

A

The Camitz abductorplasty can be used to augment the abductor pollicis brevis tendon with the palmaris longus.

Answer 141

A

Huber opponensplasty transfers the abductor digiti minimi tendon.

Answer 142

A

The Phalen-Miller opponensplasty is a transfer of theextensor carpi ulnaris tendon

Answer 143

A

The Burkhalter opponensplasty involves transfer of the extensor indicis proprius tendon.

Answer 144

A

(B) Abductor pollicis longus and extensor pollicis brevis

The volar border of the anatomic snuff box is comprised of the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons (first dorsal compartment). The dorsal border is comprised of the extensor pollicis longus (EPL) tendon (third dorsal compartment).

Answer 145

A

The volar border of the anatomic snuff box is comprised of the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons (first dorsal compartment).

Answer 146

A

The dorsal border is comprised of the extensor pollicis longus (EPL) tendon (third dorsal compartment).

Answer 147

A

(B) Extensor indicis proprius

In this 33-year-old man who has developed high median and ulnar nerve paralysis, the extensor indicis proprius is the only tendon of those listed that still has motor innervation. The patient’s injuries preclude the use of all muscle-tendon units powered by the paralyzed nerves. However, because the index finger has two independent extensor tendons, the extensor indicis proprius tendon can be used in tendon transfer.

Answer 148

A

Muscle-tendon unit must be available
Of appropriate strength
Able to be spared at the donor site (ie, function of the muscle cannot be critical to the site).
The strength of the antagonist muscle must also be opposed
Intercalary joints should have appropriate mobility
The excursion and direction of the muscle should be well matched.

In addition, the proposed tendon transfer should demonstrate integrity and synergy

Answer 149

A

(C) Splinting the PIP joint at 0 degrees

This patient has a boutonniere deformity, in which the extensor mechanism (comprised of the central slip, transverse and oblique retinacular ligaments, and lateral bands) becomes imbalanced. In patients with this deformity, the central slip is damaged and the transverse retinacular ligament is stretched. The lateral bands begin to drift volarly, eventually moving anterior to the center of rotation of the proximal interphalangeal (PIP) joint. As a result, the lateral bands flex the PIP joint, and passive extension of the PIP joint becomes impossible

Because this patient has only a stage 1 boutonniere deformity, the most appropriate management is splinting the PIP joint in extension (ie, at 0 degrees) for a minimum of six toeight months. The distal interphalangeal (DIP) joint should be unencumbered and allowed to flex actively, and an exercise program should be initiated for joint rehabilitation

Answer 150

A

Central slip, transverse and oblique retinacular ligaments, and lateral bands

Answer 151

A

atients with stage 1 deformities can passively extend the PIP joint.

Answer 152

A

With stage 2, the joint becomes contracted and cannot be extended fully, but the joint itself is not yet involved.

Answer 153

A

Degeneration of the joint is seen in a patient with a stage 3 boutonniere deformity

Answer 154

A

Splinting of the PIP joint in extension (ie, at 0 degrees) for a minimum of six to eight months. The distal interphalangeal (DIP) joint should be unencumbered and allowed to flex actively, and an exercise program should be initiated for joint rehabilitation

Answer 155

A

(A) Central and spiral cords

The central, lateral, and spiral cords each contribute to recurrent contracture of the PIP joint; the little finger is affected most frequently. The central cord develops from fascia between the neurovascular bundles and is continuous proximally with the pretendinous cord. It attaches distally to the tendon sheath over the middle phalanx. The lateral cord is adherent to the skin, while the spiral cord can occur as a continuation of the pretendinous cord or can arise at the musculotendinous junction of the intrinsic muscle. This cord straightens and courses less obliquely over time.

Answer 156

A

The natatory cord passes across the palm at the level of the web spaces and attaches to each individual flexor tendon sheath.

Answer 157

A

Cleland’s ligaments are fascial structures located dorsal to the neurovascular bundle that help to hold the skin in position duringflexion and extension of the finger.

Answer 158

A

A) Decrease adhesions

The main rationale for performing early motion exercises is to decrease adhesion formation. During the early phases of tendon healing, large amounts of collagen are deposited and form early scarring. Although this scarring is crucial for the healing of the repaired tendon, scarring will also occur in the tendon sheath and, if allowed to progress, can lead to stiffness in the involved digit. Early passive- and active-motion protocols assist in breaking apart early scarring of the tendon to the surrounding sheath.

Early motion has not shown to increase the final strength of the repair and is more likely to cause rupture. Although synovial fluid flow might be increased with tendon excursion, it does not improve outcomes. Postoperative pain is likely increased with therapy.

Answer 159

A

B) 1 week

Rupture of the flexor digitorum profundus (FDP) tendon from its distal attachment is commonly known as jersey finger. The injury is often overlooked by players and trainers and misdiagnosed as a sprained finger, but it requires more urgent management than these minor injuries. Jersey finger occurs when a flexed distal interphalangeal (DIP) joint is suddenly and forcefully hyperextended, leading to rupture of the FDP tendon at its insertion on the distal phalanx.

FDP injuries can be classified based upon the degree of tendon retraction, as described in Leddy and Packer’s grading scheme:

Type I injuries involve retraction of the profundus tendon all the way to the palm, with associated injuries to the vincula longus and vinculum brevis. Injuries to the vincula disrupt the blood supply to the tendon, necessitating surgical repair within 7 days to avoid necrosis of the tendon and a permanent contracture deformity.
Type II injuries involve retraction of the tendon to the proximal interphalangeal (PIP) joint. The tendon stump is held in place by the vincula longus, which are often intact. An avulsion fracture sometimes occurs with type II injuries, and often becomes trapped in the A2 pulley. Without an observable bony fragment on x-ray study, it is impossible to determine the degree of retraction; thus, all type II injuries should be surgically repaired within 7 days.
Type III injuries involve a large avulsion fragment that is often intraarticular. The bony fragment prevents retraction past the A4 pulley and holds the tendon in near-anatomic position, obviating the need for urgent repair. Type III injuries are amenable to repair within 2 to 3 months.
Type IV injuries are type III lesions with the addition of an avulsion of the FDP tendon from the fracture fragment. Type IV injuries are rare but require urgent repair because of the disruption to the tendon’s blood supply.

Answer 160

A

C) Free gracilis innervated by a median nerve branch

A free gracilis muscle would provide a good strength and excursion match to the native finger flexors it would replace. Vascular and nerve connections could be performed in the distal upper arm, outside of the zone of resection. While individual finger flexion would not be restored, the patient would be able to make a composite fist after this surgery.

The flexor digitorum profundus to superficialis transfer is used to treat flexor spastic contracture, typically with palmar hygiene issues, in a patient who still has some voluntary motor control. It requires the presence of flexor digitorum profundus and superficialis muscles, both of which would be removed as part of the anterior forearm compartment muscles.

The Oberlin-Mackinnon nerve transfer transfers branches of the median nerve and ulnar nerve to the brachialis and biceps muscles, respectively. It is used to restore elbow flexion and would not provide finger flexion.

A flexor pronator slide detaches the muscles originating from the medial epicondyle of the humerus and advances them distally. It is used to treat contractures of the fingers, often in patients with mild to moderate Volkmann contracture. In this patient, the flexor muscles have been resected, so this procedure is not possible.

A latissimus dorsi muscle provides broad soft-tissue coverage for wounds and can also provide a strong flexion force. It cannot reach beyond the distal elbow. It can restore elbow flexion but cannot be used as a pedicled transfer to restore finger flexion.

Answer 161

A

D) Triangular ligament

A Boutonnière deformity occurs with injury to the central tendon and injury or attenuation of the triangular ligament. The lateral bands migrate volarly to become proximal interphalangeal (PIP) joint flexors, and their action is on the distal interphalangeal (DIP) joint, extending it. The triangular ligaments are bound by the lateral bands, central slip, and terminal tendon.

The sagittal bands of the metacarpophalangeal (MCP) joint originate from the volar plate and anchor the extensor mechanism. The oblique retinacular ligament originates from the volar lateral crest of the proximal phalanx and inserts into the terminal tendon. The volar plates stabilize the MCP and PIP joints. The terminal tendon is the convergence to the lateral bands at the dorsum of the middle phalanx inserting on the distal phalanx.

Answer 162

A

A) Continued hand therapy to improve passive range of motion

This patient has adhesions after flexor tendon injury and repair. In this scenario, the recommended course of action is to continue hand therapy to improve passive range of motion. A successful functional outcome following tendon injury depends on supple joints with full passive range of motion and tendon gliding. The ultimate goal would be to perform flexor tenolysis; however, the indications are clear that the patient must have minimal soft-tissue edema, minimal scarring, and full or near-full passive range of motion.

Active tendon range of motion depends on the flexor digitorum superficialis and flexor digitorum profundus gliding within the flexor tendon sheath. Flexor tendon adhesions are a potential complication any time the flexor tendon sheath is violated, as a result of either surgery or trauma. The literature shows a reoperation rate of 6% after flexor tendon repair and an adhesion rate of 4%.

This patient is 4 months post-surgery and reports compliance with supervised hand therapy. Despite this, he has poor active and passive range of motion. Although most authors recommend waiting at least 3 to 6 months before attempting tenolysis, this patient is unlikely to improve with observation alone.

Tenolysis is a technically demanding procedure, and all patients must be counseled preoperatively that complications such as neurovascular injury, injury to the pulley system, and tendon rupture are possible outcomes. In cases of tendon rupture or patients requiring pulley reconstruction at the time of tenolysis, two-stage tendon reconstruction with implantation of a silicone rod is indicated. However, this would be a salvage procedure only and not first-line treatment.

Proximal interphalangeal (PIP) joint arthrodesis would be limited to a salvage procedure in patients who are unable to undergo tendon repair or reconstruction.

Answer 163

A

A) Boutonnière

The triangular ligament stabilizes the lateral bands dorsally, thereby preventing volar subluxation of the lateral bands to the proximal interphalangeal (PIP) joint rotation of axis, and the boutonnière deformity.

The swan-neck deformity occurs when the lateral bands sublux dorsal to the PIP joint rotation of axis. This is prevented by the transverse retinacular ligament, which acts to prevent dorsal migration of the lateral bands at the PIP joint.

Neither the mallet, quadriga, or lumbrical plus deformities are caused by volar subluxation of the lateral bands.

Answer 164

A

A) Central slip disruption

This is the basis of the Elson test for central slip disruption of the extensor mechanism of the finger. When the proximal interphalangeal (PIP) joint is maximally passively flexed, the central slip is normally pulled distally, resulting in slack in the terminal tendon. Injury to the central slip eliminates this slack through the lateral band and allows extensor tension to be generated at the distal interphalangeal (DIP) joint. Thus, with central slip injury, the DIP joint can be actively extended with maximal PIP flexion.

Swan neck deformity results from terminal extensor tendon disruption and total inability to extend the DIP joint independent of PIP position. Flexor digitorum profundus (FDP) avulsion results in inability to flex the DIP joint. In the Elson test, DIP flexion is always possible. PIP volar plate injury may result in jamming of the volar plate within the PIP joint and paradoxical inability to flex (extension contracture) at the PIP joint. There will also be hyperextension PIP joint pain and laxity. Sagittal band disruption results in inability to actively extend at the metacarpophalangeal joint, but the finger can often maintain extension if passively placed in this position.

Answer 165

A

A) Complete immobilization for 4 weeks

Early motion protocols are standard for adult tendon repairs but are not generally suitable for very young children due to poor compliance. Children have a remarkable ability to regain motion after tendon injury, especially for repairs or grafts that are outside of Zone II. In this vignette, the reconstruction was in Zone III, and the prognosis for regaining full motion even after a month of immobilization is excellent. Moreover, it is highly unlikely that a child of this age will predictably comply with splint wear and motion restrictions for the duration of tendon healing. Thus, the risk of early rupture outweighs the risk of stiffness. There are advocates of successful early motion protocols in children with Zone II tendon repairs, but most studies have failed to demonstrate an appreciable benefit of such a practice.

Answer 166

A

C) Increased FDP and FDS excursion

Low force and moderate excursion therapy protocols continue to be the most effective protocol following flexor tendon repairs. However, increasing the applied force to the repair site during postoperative rehabilitation beyond 5 N does not accelerate accrual of repair site strength after a multistranded repair. In vivo repair, results have shown that early active mobilization may limit tendon end softening and loss of repair strength that generally occurs after the first 7 days.

The mode of rehabilitation described was popularized by Strickland and has been shown to improve outcomes of Zone II repairs, probably due to both increased absolute as well as relative tendon excursions. However, in order to reduce the potential increased repair rupture rate, at least four-strand repair is required. This increased excursion leads to fewer tendon adhesions.

Because the fingers are flexed by rubber bands, the Kleinert technique predisposes the patient to flexion contractures. A combination of the Duran passive range of motion and the Kleinert technique improves the results.

Answer 167

A

D) Intersection syndrome

Intersection syndrome is synovitis of the second dorsal compartment. It is located where the abductor pollicis longus and extensor pollicis brevis cross the extensor carpi radialis longus and extensor carpi radialis brevis. The syndrome often occurs in athletes with repetitive forceful extension. The swelling is located 4 to 6 cm proximal to Lister tubercle.

Basal joint arthritis and synovitis would have tenderness located at the wrist crease at the carpometacarpal joint and may have x-ray findings. de Quervain is synovitis of the first dorsal compartment, which would be located over the radial styloid and have a positive Finkelstein sign. Wartenberg syndrome is radial sensory nerve compression where the nerve exits the supinator muscle. Symptoms would be paresthesia over the radial nerve distribution and a Tinel sign. Extensor pollicis longus tendinitis is synovitis of the third dorsal compartment with vague dorsal wrist pain and tenderness, usually over the Lister tubercle with exacerbation with thumb extension.

Answer 168

A

D) Tendon transfer

The most appropriate management for the patient described is tendon transfers to restore wrist, finger, and thumb extension. Following closed brachial plexus injuries, patients should receive CT scan or MR myelogram and electrodiagnostic studies at 3 to 4 weeks. This will allow enough time to see pseudomeningoceles and denervation changes. The electromyography and nerve conduction studies are generally repeated at 14 to 16 weeks to look for signs of regenerating axons, and this information is used to help determine the strategy for reconstruction. Surgery is recommended in the absence of clinical or electrical evidence of recovery.

The patient described has late symptoms, and any strategy that involves attempting to repair or reconstruct the injured nerves is not recommended. After 12 to 18 months, useful motor recovery is unlikely due to intraneural fibrosis, loss of Schwann cells, muscle atrophy, and motor end-plate degeneration. Tendon transfers may be done at any time assuming that there are suitable donor tendons (at least 4/5 strength and full excursion) and that full passive mobility is present. In this example, the patient has adequate donor tendons from the median and ulnar nerves, and full passive range of motion. Examples of tendon transfers include: palmaris longus to extensor pollicis longus, pronator teres to extensor carpi radialis brevis, and flexor carpi ulnaris to extensor digitorum communis.

Early or subacute exploration of the injured plexus with resection and intraplexal nerve grafting can be used with ruptures or neuromas that do not conduct a nerve action potental across the lesion. In adults, grafting is reserved for C5, C6, and C7 to restore shoulder abduction, elbow flexion, elbow extension, and wrist extension. Nerve grafting for lower trunk injuries in adults is generally not successful due to the length and time required for the regenerating axon to reach the distal target muscles.

Nerve transfers have become a very useful and versatile tool for reconstruction of brachial plexus and peripheral nerve injuries. A less important distal nerve is sacrificed to replace the function of a more important nerve. Nerve transfers can be performed in preganglionic injuries and to decrease the distance to the target muscle for reinnervation. Ideally, nerve transfers are performed within 6 months of the injury. Studies have shown greater than 70% will achieve M3 function for elbow flexion and shoulder abduction. Common donor nerves include the spinal accessory, intercostals, anterior interosseous, and triceps branch.
Other options for late reconstruction include pedicled muscle transfers and neurotized functional free muscle transfers. The latissimus dorsi muscle can be used to restore elbow flexion or elbow extension but will not reach beyond the elbow. Currently, free muscle transfer is the best option to restore hand and wrist function in complete brachial plexus palsy.

Answer 169

A

E) Stiffness of the interphalangeal joints

Of the options listed, the most likely option to result in poor outcome in the setting of delayed tendon repair is stiffness of the interphalangeal joints. Hand therapy directed at achieving passive range of motion of the finger before reconstruction may make repair possible and should be attempted before proceeding with surgery.

Although poorly controlled diabetes increases the risk of perioperative infection, it would not impact the ability to perform a reconstruction. Likewise, the amount of time that has passed since the initial injury places the patient outside the range typically accepted for delayed primary repair, but would not directly affect a reconstruction.

Digital nerve injury requiring repair/reconstruction has been considered a relative contraindication to repair. The increased two-point discrimination in this patient suggests a prior injury with recovery similar to what might be expected with primary nerve repair. In this setting, the need for concomitant digital nerve repair is unlikely.

Although thick, the cutaneous scar is mobile, suggesting that it is not contributing to the lack of motion at the interphalangeal joints. Immature scars or wounds requiring further reconstruction would also be contraindications to reconstruction.

Answer 170

A

E) No testing is necessary; physical findings are sufficient

The patient described has a significant wrist injury until proven otherwise. Physical examination will be the most helpful in making a determination regarding what should be done next. Electromyography/nerve conduction study typically does not give actionable information until 3 weeks or more after injury. Ultrasonography may be helpful but would not give more information than one could get from a thorough physical examination and would likely be painful as the probe is pressed on the wound. CT angiography can be critical preoperatively if there was a concern regarding inflow. Magnetic resonance angiography would be revealing but would be expensive and unnecessary in this setting.

The patient was taken to the operating room for exploration. Intraoperative and postoperative images are shown.

Answer 171

A

D) Juncturae tendinum

Juncturae tendinum are tendon-like bands that connect the long, ring, and little finger extensor digitorum communis tendons. If the long finger extensor tendon is lacerated proximal to the attachment of the juncturae tendinum between the long and ring fingers, the ring finger extensor digitorum communis tendon will apply extension force to the distal long finger extensor tendon via the juncturae tendinum and produce metacarpophalangeal (MCP) extension.

Interossesous and lumbrical muscles produce flexion of the MCP joint. The deep transverse metacarpal ligament stabilized the metacarpal heads relative to each other but does not produce motion at the MCP joint. In this patient, the tendon is visible and noted to be completely lacerated; therefore, the paratenon is not intact.

Answer 172

A

E) No intervention is indicated

No intervention is indicated for this patient. The principles of tendon repair and reconstruction have evolved since the first description of primary tendon repair in Zone II in 1967. Proper patient selection is essential before attempting any reconstruction to restore functional motion.

The indications for grafting or reconstructing through an intact flexor digitorum superficialis (FDS) are narrow, and sacrifice of an intact FDS is generally not recommended. Most of the functional arch of motion is maintained with the superficialis tendon, and many patients will function well with an FDS digit alone. Profundus reconstruction through an intact FDS is most often reserved for patients between 10 and 21 years old with high occupational demands for dexterity such as artists or musicians. This patient is beyond the recommended age range for an optimal outcome and is reporting no functional deficits as a result of her injury. In addition, delayed symptoms may give a clue to the patient’s ability to comply with rigorous postoperative therapy.

Delayed primary repair can be attempted up to several weeks after a flexor tendon injury, and up to 6 weeks in pediatric patients. However, 9 months is well beyond the time when a primary repair would be possible. The FDS from an adjacent finger can be used as the proximal motor in cases of tendon graft reconstruction or tendon repair rupture. This is a consideration if the native proximal stump of the profundus is significantly damaged or scarred and has poor excursion. In this patient, reconstruction is not indicated, and nothing is mentioned regarding the proximal tendon.

A distal interphalangeal (DIP) joint arthrodesis may be indicated if the DIP joint is unstable with a well-functioning proximal interphalangeal (PIP) joint. Tenodesis of the flexor digitorum profundus stump is another option for soft-tissue DIP stabilization.
Tendon reconstruction is indicated when a delay in treatment makes primary tendon repair impossible. A healed wound with full passive range of motion, absence of significant scarring, and an intact flexor retinacular pulley system are considered prerequisites for a single-stage reconstruction. In any other situation, a two-stage reconstruction with implantation of a temporary silicone rod is indicated. This would be the reconstructive strategy of choice for this patient if the FDS tendon were also involved in the original injury.

Answer 173

A

B) The same tension as it was in the leg

Functional muscle transfers are a way to restore motion that has been lost. The gracilis muscle is a common option for this kind of transfer. To optimize the outcome, the muscle should be inset at the same tension it was under in the leg.

The physiologic basis for this technique is that muscle fibers function best at a particular length/tension relationship. Muscles are typically under ideal tension in their donor position. When transferred, a muscle can be placed under too much or too little tension. If a muscle is overstretched, there is little overlap of the actin and myosin units, and the contractile force is weak. If the muscle is under too little tension, the actin and myosin units aren’t able to achieve maximal contraction. Insetting a muscle under no tension produces the same result as insetting it under less tension.

Answer 174

A

D) Repair the FDS and FDP tendons

Tendon rupture can occur early or late, up to 6 to 7 weeks, with days 7 to 10 being most common. Reoperation with repair of the previously repaired tendons will yield results similar to primary repair. Therefore, discontinuation of therapy and rod placement are incorrect. Repair should be undertaken before 2 weeks due to tendon shortening.

Repair of both tendons will retain independent finger motion with greater power and decreased chance of proximal interphalangeal joint hyperextension. There will also be a better bed for FDP gliding. Therefore, flexor digitorum superficialis transfer is incorrect. Arthrodesis is reserved for failed treatment.

Answer 175

A

C) Extensor carpi radialis brevis

The flexor digitorum superficialis and flexor carpi radialis musculotendinous units were lacerated in the original injury. They would not be appropriate donor motors due to this. Brachioradialis transfer to the flexor pollicis longus transfer has been reported for patients with cervical spine injuries, but it is not used for transfers to restore intrinsic muscle function. The abductor pollicis brevis cannot be used to correct a claw deformity due to its small size and position in the thenar eminence; in addition, for this patient, its innervation was injured in the original trauma.

Both the extensor carpi radialis longus and brevis have been described as a tendon transfer. Neither muscle has been affected by the initial injury. Whichever tendon is not harvested can power wrist extension along with the extensor carpi ulnaris. The tendon does need to be elongated with a graft.

Answer 176

A

E) Transfer of the EIP tendon to the extensor pollicis longus tendon

The scenario depicts a classic case of extensor pollicis longus (EPL) tendon rupture following distal radius fracture. The reported incidence of EPL tendon rupture ranges from 0.2 to 3%. Ruptures can occur after internal or external fixation due to impingement of hardware on the tendon or due to ischemic changes in the tendon due to swelling of the tendon and the third dorsal compartment.

Reconstruction of the EPL tendon can be accomplished either by tendon transplantation, typically the palmaris interposition between the proximal and distal healthy segments of the EPL tendon, or by transfer of the EIP to the distal segment of EPL tendon. When identified and treated before the EPL muscles retract and shorten, equivalent outcomes can be achieved. Later treatment necessitates tendon transfer.

Fusion of the thumb IP joint may be useful in flexor pollicis longus ruptures that cannot be repaired, but this would not restore thumb retropulsion.

Fusion of the CMC joint can alleviate pain from basal joint arthritis, but would result in further loss of motion of the thumb.

Transfer of the EIP to the abductor pollicis brevis and transfer of the anterior interosseous nerve to the recurrent branch of the median nerve are techniques for restoring thumb palmar abduction/opposition and would not restore retropulsion/extension.

Answer 177

A

E) Volar plate laxity of the proximal interphalangeal (PIP) joint

Swan-neck deformity can occur in the post-traumatic setting as well as in the rheumatoid arthritis population. The PIP joint hyperextends, and the DIP joint flexes. Unlike boutonnière deformity, which is always initiated by a rupture of the central slip of the extensor mechanism, the origin of a swan-neck deformity can be at the DIP, PIP, or MCP joint. Regardless of the initiating problem, a swan-neck deformity can only occur if there is laxity of the volar plate of the PIP joint to allow hyperextension.

Flexor digitorum profundus avulsion would lead to inability to flex the DIP joint and would not cause hyperextension of the PIP joint. The oblique retinacular ligament can be used to repair a swan-neck deformity but is not causative of the pathology. Palmar subluxation of the MCP joint can lead to a swan-neck deformity in rheumatoid arthritis patients, but the photograph and x-ray study show this is not present in this patient. Rupture of the central slip of the extensor mechanism would lead to a boutonnière deformity.

Answer 178

A

E) Swan-neck

Flexion deformity of the distal joint seen in mallet finger will lead to secondary hyperextension of the proximal joint. This occurs in a zigzag fashion because of the imbalance of forces. If the terminal tendon is displaced proximally, the conjoined tendons will slide proximally and become extensors to the proximal joint.

A boutonnière deformity is a flexion deformity of the proximal joint from disruption of the central slip. The lateral slips migrate volarly becoming an extensor to the distal joint which then hyperextends. Clinodactyly is a genetic condition in which there is a curvature of the fifth finger toward the fourth finger. A hook nail usually results from loss of nail bed support, usually after amputation. Camptodactyly is also a genetic condition in which there is a fixed flexion deformity of the proximal joint of the little finger.

Answer 179

A

E) Splinting of the PIP in extension and active DIP flexion

The patient has a boutonnière deformity that is passively correctable. In most instances, this can be successfully managed with splinting of the PIP joint in extension while allowing active DIP flexion. Splinting of the PIP in extension helps restore central slip continuity; active DIP flexion with the PIP joint extended draws the tight, volarly displaced lateral bands into a more dorsal position while reducing DIP joint hyperextension. Holding the PIP and DIP joints both in extension will not correct the deformity. Open central slip repair is indicated if there is an open wound, but that is not the case in this scenario. Resection of the distal lateral bands only is a reasonable treatment for chronic deformity by relaxing the lateral bands. There is no role for resection of both lateral bands and oblique retinacular ligament in the management of this condition.

Answer 180

A

C) Flexor carpi ulnaris

The most appropriate muscle to transfer for restoration of finger extension is the flexor carpi ulnaris.

The radial nerve can be injured as a result of humerus fracture and/or surgery as it crosses the spiral groove of the humerus. The resultant radial nerve palsy will cause inability to extend the wrist, fingers, and thumb.

Reinnervation of the muscle ideally should be completed within 12 to 18 months following injury to allow for recovery. In this patient who has radial nerve palsy after humerus fracture, the time following injury has been too long, so nerve repairs or nerve transfers are not a viable option, and tendon transfer is the procedure of choice.

Tendon transfer involves the use of a noncritical or expendable donor tendon to provide a missing function. The tendon to be transferred should have adequate strength and range of motion to provide the desired function. Ideally, the tendon used should have synergistic action and allow for tenodesis to facilitate reeducation.

Transfer of the flexor carpi ulnaris to the extensor digitorum communis will provide extensor function of the fingers, as it has adequate power and excursion and takes advantage of the linkage between wrist flexion and finger extension. Other typical tendon transfers for finger extension in radial nerve palsy include the flexor carpi radialis and the flexor digitorum superficialis.

The brachioradialis is a radial nerve innervated muscle and will not be functioning in this patient who has a high radial nerve palsy. In low radial nerve palsies, it can be used to restore thumb extension. The brachioradialis can also be used to restore finger or wrist extension, as well as finger or thumb flexion in the appropriate patient.

The extensor carpi radialis longus is not functional in this patient with radial nerve palsy. It can be used as a transfer for finger flexion in the appropriate patient.

The palmaris longus does not have sufficient power to provide finger extension. It can be used as a transfer for thumb extension.

The pronator teres has adequate power but less excursion. It is typically used to restore wrist extension rather than finger extension.

Answer 181

A

D) Two-stage tendon reconstruction

When patients present with zone II flexor injuries, it is optimal to repair both flexors within 10 days after the injury before the tendons retract excessively preventing primary approximation of the tendon ends. Late flexor injuries (after 2 weeks) in zones I, III, IV, and V can be managed with single-stage tendon grafting. However, when the injury is in zone II, the sheath has collapsed and tendon grafts cannot be easily pulled under intact pulleys, necessitating pulley reconstruction over a silicone rod in the first stage. Then, in a second stage, the tendon rod is replaced with the tendon graft pulled into the sheath in the proximal to distal direction after suturing the graft to the rod. The tendon is repaired first distally to bone, and then the appropriate tension is set on the proximal juncture repair of the graft to the motor tendon (usually the flexor digitorum superficialis to avoid quadriga and lumbrical plus posture). Two-stage tendon grafting in general is recommended for zone II flexor repairs that present late, require simultaneous critical pulley reconstruction (A2, A4), or if volar finger soft-tissue reconstruction is required. Tendon transfer options would not be long enough to span the defect out to the distal phalanx and the flexor digitorum profundus from other fingers should not be sacrificed. Further observation is certainly not warranted.

Answer 182

A

B) 10 cm

For both two-strand and four-strand locking core repair methods, the length of core suture purchase significantly influences both resistance to gapping and also ultimate strength to breaking. The optimal length of purchase is between 0.7 and 1.0 cm. Increased length of purchase from 0.7 to 1.2 cm does not increase the repair strength. Purchase length of 0.4 or less greatly reduces repair strength.

Answer 183

A

B) Continuous extension splinting of the distal phalanx

The most appropriate management is continuous extension splinting of the distal phalanx.

The patient has sustained a mallet injury to the left ring finger. There is tearing of the terminal extensor tendon from its insertion at the base of the distal phalanx, resulting in inability to extend the finger at the DIP joint. On occasion, these injuries may be associated with an avulsion fracture from the dorsal aspect of the distal phalanx.

The majority of closed mallet injuries (Type I) in Zone I of the extensor tendon can be treated by continuous extension splinting for 6 to 8 weeks. It is important that the finger not be allowed to flex at the DIP joint during this time period to avoid disruption of healing.

Arthrodesis of the DIP joint is reserved for cases of DIP joint arthritis and would not be necessary in this patient.

Exploration and suture of the tendon can be performed, but results are no better than closed treatment due to the difficulty of obtaining adequate repair of the thin tendinous substance at this level. Additionally, the patient will still require prolonged immobilization of the DIP joint after open repair. Exploration and suture of the tendon is used to treat Type II (open) mallet injuries.

Open repair with reinsertion of tendon into bone is performed in flexor digitorum profundus avulsion injuries.

Splinting of the PIP joint in extension with the DIP joint free is used to treat Zone III extensor tendon injuries (central slip avulsion injuries).

Answer 184

A

C ) Median nerve

The palmaris longus tendon is located in the middle of the volar wrist, and the median nerve is directly dorsal to this structure. In patients with palmaris longus lacerations at the level of the wrist, it is common to also find the median nerve to be injured.

The palmaris longus tendon is absent in 20% of patients. The superficial volar wrist tendons are the flexor carpi radialis, palmaris longus, and the flexor carpi ulnaris. The flexor superficialis tendons lie dorsal to the superficial flexors. However, the median nerve rests immediately dorsal to the palmaris longus at the level of the wrist. The flexor superficialis tendons are in a stacked position such that the long and ring finger flexor superficialis tendons rest volar to the index and little finger flexor digitorum superficialis tendons. The flexor digitorum profundus tendons are deep or dorsal to the flexor superficialis tendons and lie in a flat array corresponding to each finger the tendon is coursing to distally. The ulnar nerve and artery are found dorsal to the flexor carpi ulnaris. Accordingly, injuries involving the flexor carpi ulnaris tendon are frequently associated with ulnar nerve and artery injuries.

Answer 185

A

D ) Splinting of the DIP joint at 0 degrees

Avulsions of the terminal extensor tendon, as well as mallet fingers, are some of the most common hand injuries. Tendon avulsion from the distal phalanx may involve the tendon itself or a portion of its bony attachment. In the absence of large joint subluxation or fractures involving large fracture fragments, conservative nonoperative management with splinting is the recommended treatment.

Conservative treatment involves splinting in extension or slight hyperextension. This can involve prefabricated stack splints, malleable aluminum splints, or casting. Outcomes of each of these treatments are similar, but the type of splinting is generally more limited by skin irritation. Pin fixation for the DIP joint is recommended for patients who cannot tolerate splinting or those with special circumstances, such as a surgeon who requires unencumbered use of the hand. Pin fixation should cross the DIP joint only.

Answer 186

A

E ) Tendon transfer of EIP to index EPL tendon

EPL tendon rupture occurs in 1% of fractures of the distal radius after closed reduction. The incidence of tendon rupture after closed treatment of distal radius fracture is actually greater than that of open treatment and plate fixation. Tendon ruptures may occur early, due to bone spurs, but they also may occur late, years after the fracture. This is believed to be due to an inflammatory synovitis in the area of the third dorsal compartment and a relative ischemia of the EPL tendon in this area. Ultrasound can help establish the diagnosis; the optimal treatment is tendon transfer from the EIP tendon. Arthrodesis of the thumb IP joint can prevent the flexion deformity of a tendon rupture, but it is not a preferred reconstruction method for a young, active person. Unless there is significant pathology at the distal radius, no specific treatment is required for the bone. Delayed primary repair of the EPL tendon is rarely possible.

Answer 187

A

C ) Normal passive range of motion

The most important preoperative achievement is the restoration of good passive flexion of the involved digit. This will allow active range of motion in the postoperative period.

Preoperative examination clearly shows no function of the flexor digitorum superficialis tendon. Therefore, in the setting of the sharp injury, it would not be expected to be improvable.

The location of the proximal FDP stump is not appropriate because it is not a significant factor in timing secondary tendon reconstruction; it would not be reasonable to consider planning a delayed primary repair 3 months out. And with a Zone 2 laceration and no FDP function, the FDP stump will be in the palm, due to tethering by the lumbrical muscle.

Confirmation of the presence of a palmaris longus at either forearm is not appropriate because the palmaris is not the only donor tendon for secondary finger flexor reconstruction. The plantaris is a viable option as well, as are the long toe extensors.

Preoperative strengthening of grip is not appropriate because it would do nothing to prepare the little finger for reconstruction.

Answer 188

A

A ) Central slip

The Fowler central slip tenotomy is well known, but seldom used. The central slip or tendon inserts on the base of the middle phalanx and acts on the proximal interphalangeal (PIP) joint. A central slip tenotomy will rebalance the extensor mechanism such that the terminal tendon will be able to extend the distal interphalangeal (DIP) joint in patients with a chronic mallet finger. However, many clinical and anatomical studies have shown that the central slip tenotomy may not restore full extension in patients with a preexisting lag of approximately 36 degrees.

Tension on the lateral bands also extends the DIP.

Release of the oblique retinacular ligament (ORL) or the lateral bands would, therefore, not assist in extension of the DIP joint.

Releasing the terminal tendon will only worsen the mallet finger because this is the structure that is disrupted in an open or closed mallet injury. Release of the triangular ligament would likely create a boutonnière deformity. PIP extension (produced by other tissues in the extensor mechanism) elongates the ORL, creating passive tension that extends the DIP.

Answer 189

A

E ) Volar subluxation of the lateral bands

Disruption of the central slip of the extensor tendon at its insertion into the base of the middle phalanx results in extensor lag at the PIP joint of the finger. If this deformity is left untreated, then a boutonnière deformity may result. This deformity results from subsequent volar subluxation of the lateral bands.

Disruption of the terminal extensor tendon does not result in boutonnière deformity; in fact, the use of the extensor tenotomy distal to the triangular ligament may be used for correction of chronic boutonnière deformity. Intrinsic tightness of the lumbricals and sagittal band disruption do not initiate boutonnière deformity. Quadriga effect results from an imbalance of tendon forces between adjacent fingers and is also not responsible for progression to boutonnière deformity.

Many surgeons consider the results of surgical treatment for boutonnière deformity unpredictable, and so they try splint immobilization to first regain extension and then allow the central slip to heal, even in delayed presentations. Surgical options include reattachment of the central slip and various reconstructions of the lateral bands including tenotomy, tendon grafting, and tendon transfer. Management strategies vary depending on the time since injury and the degree and ability to correct a PIP joint flexion contracture.

Answer 190

A

B ) Forced distal interphalangeal (DIP) joint extension with simultaneous maximal flexion effort

Jersey injury occurs when a player grabs the opposing player’s jersey. The DIP joint is in a flexed position and when the tackle is broken, there is a forced extension. Flexor digitorum profundus (FDP) avulsion occurs 75% of the time in the ring finger. In Type I, the tendon only retracts into the palm and requires urgent repair and reinsertion within 7 to 10 days. In Type II, the tendon retracts to the PIP joint level being tethered by the long vinculum. Repair can be delayed 6 to 12 weeks. In Type III, a large bony fragment blocks the tendon from entering the A4 pulley and can be repaired at any time. The FDP insertion is avulsed from the distal phalanx with or without bone fragments. Force applied in any of the other vectors would not create FDP avulsion.

Answer 191

A

D ) Flexor pollicis longus

The flexor pollicis longus tendon courses through the vicinity of the scaphoid. Scaphoid fracture malunion or scaphoid arthritic spurs can result in ruptures to the flexor pollicis longus tendon. The other tendons described do not course in the area of the scaphoid and would not be injured with disease in the area of the scaphoid.

Answer 192

A

Length of moment arm Motion of PIPJ
C. Increase Decrease

The moment arm of the joint refers to a perpendicular line drawn from the mid axis of the joint to the tendon causing movement in the joint. The moment arm represents torque and can be thought of as power at an individual joint. The system can be broken down into simpler terms by thinking of wrenches of different lengths. The longer the wrench, the greater the amount of power can be placed in the turning of a nut onto a bolt. The same applies to the joints of the hand. As the tendon itself gets farther away from the center of rotation of the joint (increased moment arm), there is an increase in the torque on that joint, and, in turn, the power acting upon the rotation of the joint. As a flexor tendon gets farther away from the PIP joint (increase in moment arm), for the same strength of pull, there is an increase in force to that joint. However, there is also a loss of efficiency because the excursion of the tendon needs to increase more and more as the tendon itself gets farther away from the axis of rotation. A greater amount of excursion is required to flex the joint through to a given angle. Therefore, only an increase in moment arm, decrease in PIP joint motion, and increase in power is an appropriate response. This has clinical significance in situations such as those presented in the scenario described. Cutting the A2 pulley allows the tendon to migrate farther in a palmar direction, or “bowstring” away, from the axis of rotation. This yields an increase in the moment arm, a decrease in tendon excursion, and, ultimately, an increase in power, with the loss of efficiency. The range of motion is decreased as the flexor tendons can no longer flex the joint fully. This effect is strongest in the A2 and A4 pulleys, which prevent bowstringing of the tendons at the proximal and middle phalanges, respectively.

Answer 193

A

D ) Repair FDP tendon

Ruptures of repaired tendons usually occur postoperative days 7 through 10. The best way to diagnose the rupture is MRI when active flexion is relatively contraindicated. Early ruptures can be managed with urgent re-repair. Tendon transfers and grafting should be reserved as secondary reconstruction procedures and should not be needed when the native FDP is available and not shortened. Fusion should be reserved for salvage and in patients where shorter recovery times are beneficial, such as laborers. Doing nothing can lead to swan-neck deformities, adhesions, and stiffness.

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