Wrist 01-22 Flashcards
Following a fall 2 hours ago, a 23-year-old man reports increasing tingling and pain in the left thumb and index finger. X-ray studies of the left wrist are shown. Attempts at reduction fail. Which of the following is the most appropriate next step in management for this patient?
A) Closed reduction and percutaneous pinning
B) Exploration and wrist arthrodesis
C) External distractor placement
D) Open reduction and internal fixation
E) Proximal row carpectomy
The correct response is Option D.
This patient has sustained a Mayfield III greater arc perilunate injury. The x-ray studies show a scaphoid waist fracture along with a disruption of Gilula’s lines. The lateral view shows the lunate in its fossa with the remaining carpus displaced dorsally. In a closed injury, attempted reduction in the emergency department, often accompanied by sedation, is an appropriate first step. If reduction is successfully performed and the patient has minimal median nerve symptoms, they can be safely discharged home with plans to return within the week for repair. If reduction is not possible, as in this case, then the patient should be admitted to the hospital for open reduction and internal fixation in the form of screw fixation of the scaphoid fracture and scapholunate ligament tear versus K-wire fixation.
In this case, given the patient’s worsening median nerve compression symptoms, acute carpal tunnel syndrome should be considered, and a carpal tunnel release should be performed concurrently with the open reduction and internal fixation. If the resources are not available to perform definitive repair of the bone and joint injury, acute carpal tunnel release is still needed to preserve viability of the median nerve. If the nerve and bony procedures can be done concurrently, by using the volar approach, the carpal tunnel can be easily accessed and released during the approach to reach the displaced lunate. Following this, often a dorsal approach is used to address concurrent scaphoid injuries.
Proximal row carpectomy is reserved for those missed injuries with chronic pain and instability. This patient presents with an acute injury so this would not be recommended. Similarly, wrist arthrodesis is also reserved for chronic injuries in those who have painful and unstable joints, but this would also be a poor choice in this patient.
While some authors use staged reconstruction with a distractor to address soft tissue shortening in late presentations, the two-stage approach would not be necessary in an acute injury like this.
Closed reduction and percutaneous pinning would be difficult since reduction attempts in the emergency department have been unsuccessful, and it would not address the carpal tunnel.
A 65-year-old male laborer presents with worsening pain in the left thumb. An x-ray study is shown. Which of the following is the most important ligament to prevent radial subluxation of the first metacarpal at the carpometacarpal joint?
A) Anterior oblique
B) Dorsal central
C) Posterior cruciate
D) Transverse metacarpal
E) Ulnar collateral
The correct response is Option A.
This patient presents with severe osteoarthritis of the carpometacarpal (CMC) joint of the thumb. The thumb metacarpal is in adduction, and the proximal phalanx is in hyperextension. The complex range of motion of the thumb basal joint is achieved through stability from 16 ligaments. Of the choices given, only the anterior oblique ligament is in the thumb at the basal joint. It has been found to be the most important preventative measure against radial subluxation in cases of CMC arthritis in biomechanical studies. It originates on the volar tubercle of the trapezium and inserts on the thumb metacarpal volarly. In cases of severe thumb CMC arthritis, the progressive ligamentous incompetence of the anterior oblique ligament and dorsal radial ligament allow the thumb metacarpal to migrate dorsally and proximally. The dorsal radial ligament is also important for basal joint stabilization, while the other ligaments of the thumb basal joint are not as important.
The ulnar collateral ligament is located at the metacarpophalangeal (MCP) joint of the thumb, and rupture leads to instability of that joint as seen with gamekeeper’s thumb. The dorsal central ligament is not involved in CMC joint subluxation. The deep transverse metacarpal ligaments are located in the hand between the metacarpal heads and assist in supporting the metacarpal arch. The posterior cruciate ligament helps stabilize the knee by preventing the tibia from slipping posteriorly when flexed.
A 55-year-old laborer presents with radial-sided wrist pain and swelling with activities. A 6-month course of splinting, activity modification, and nonsteroidal anti-inflammatory drugs failed to relieve his symptoms. A wrist x-ray study is shown. Which of the following is the most appropriate surgical option for durable reconstruction in this patient?
A) Scaphocapitate arthrodesis
B) Scaphoidectomy with four-corner arthrodesis
C) Scaphoid open reduction and internal fixation
D) Scapholunate ligament reconstruction
E) Scaphotrapeziotrapezoid arthrodesis
The correct response is Option B.
This patient presents with a scaphoid nonunion advanced collapse arthritis pattern (SNAC). The arthritic pattern follows a pattern very similar to scapholunate advanced collapse (SLAC). Watson and Ballet (JHS, 1984) recognized that chronic scapholunate ligament incompetence led to a predictable sequence of arthritic wear at the radioscaphoid junction (scapholunate advanced collapse [SLAC] stages I and II), later progressing to involve the midcarpal joint (SLAC stage III), usually sparing the spherical radiolunate articulation. Four-corner arthrodesis (capitate-lunate-triquetrum-hamate) with scaphoid silicone prosthetic replacement (silicone replacement later omitted) was Watson and Ballet’s recommended surgical treatment and preferred over proximal row carpectomy.
The SLAC pattern of arthrosis is thought to be due to traumatic injury to the scapholunate ligament. Calcium pyrophosphate dehydrate crystal deposition disease (CPPD, or pseudogout) has been reported to be a frequent cause of SLAC-type x-ray changes as well. Scaphoid fracture nonunion can lead to a similar degenerative arthritic pattern of the wrist, called scaphoid nonunion advanced collapse (SNAC).
Symptomatic treatment with splints, modalities, and injection may suffice in many patients. There are no studies on the long-term success of nonsurgical treatment for SLAC or SNAC wrist, nor are there any long-term natural history studies. Surgical treatment options for either SLAC or SNAC wrist include partial or complete wrist arthrodesis, proximal row carpectomy (PRC), denervation, or radial styloidectomy. SNAC wrist has the additional potential treatment option of excision of the distal ununited scaphoid fragment. Most studies concerning treatment of SLAC/SNAC wrist have focused on the results of four-corner arthrodesis with scaphoid excision or PRC. Controversy exists concerning whether PRC, or a modification thereof, may be performed when the capitate has arthritic changes.
Scaphocapitate arthrodesis, with resection of the lunate, is a treatment option for late-stage Keinböck disease. Scaphocapitate arthrodesis leaves the radioscaphoid joint in place, making it inappropriate for the patient in this case who has radioscaphoid arthritis. Open reduction and internal fixation of the scaphoid is not indicated here, since the arthritic change noted on x-ray study is the sequela of an old scaphoid fracture nonunion, which has now gone on to advanced collapse arthritis. There does not appear to be too much arthrosis in the scaphotrapeziotrapezoid (STT) joint, with the more likely source of the patient’s pain related to the radiocarpal joint, so an STT fusion would not be indicated here. This arthrosis is the result of a chronic scaphoid nonunion with subsequent carpal collapse, so repair of the SL ligament would not be indicated.
A 40-year-old man fell on his outstretched right wrist while snowboarding 12 months ago. His injury is displayed in the posteroanterior view of the right wrist on the x-ray study shown. Assuming a pattern of dorsal intercalated segment instability, a lateral view of the wrist is most likely to show the lunate bone in which of the following positions relative to the adjacent carpal bones?
A) Lunate anatomic, scaphoid extended
B) Lunate extended, scaphoid flexed
C) Lunate flexed, scaphoid extended
D) Lunate flexed, triquetrum anatomic
E) Lunate flexed, triquetrum extended
The correct response is Option B.
The posteroanterior x-ray study of the right wrist demonstrates static scapholunate (SL) dissociation with more than 3 mm of widening between the scaphoid and lunate bones. In a normal wrist, with radial to ulnar deviation of the wrist, the proximal carpal bones go into flexion then extension. With ulnar deviation, the hamate bone pushes the triquetrum into relative extension, while the scaphotrapezium-trapezoid (STT) ligament pulls the scaphoid into extension. The lunate follows the direction of its counterparts. With radial deviation, loading across the STT joint pulls the scaphoid into flexion; the lunate and triquetrum follow while translating dorsally and pronating.
When there is complete dissociation between the scaphoid and lunate, the dorsal SL ligament and secondary stabilizers (such as the dorsal intercarpal ligament) have failed. Dorsal intercalated segment instability (DISI) describes the abnormal position of the lunate relative to the long axis of the radius. Secondary to the loss of the SL and associated stabilizers, the scaphoid falls into a position of flexion and pronation, while the triquetrum pulls the lunate into the triquetrum’s preferred position of extension given the intact lunotriquetral ligament. Additionally, the lunate’s configuration with a narrower dorsum and volarly inclined radial joint surface plays a role. Volar intercalated segment instability (VISI) describes the pattern of lunate flexion with disruption of the lunotriquetral ligament; the lunate is pulled into flexion with the scaphoid while the triquetrum falls into its normal tendency to extend. The dorsal radiocarpal ligament has been implicated as well in VISI pattern deformity.
A 28-year-old man presents to the emergency department with acute pain in the left wrist after a motorcycle collision. X-ray studies of the left wrist are shown. Which of the following ligaments maintains its attachment to the lunate?
A) Dorsal intercarpal
B) Lunotriquetral
C) Radioscaphocapitate
D) Scapholunate
E) Short radiolunate
The correct response is Option E.
This patient has type IV perilunate dislocation, or lunate dislocation. This represents a complete disruption of the ligamentous stabilizers about the lunate except for the maintained short radiolunate ligament that the lunate rotates on. These injuries are high energy and can be ligamentous only (lesser arc injuries) or include fractures (greater arc injuries), and they are then termed perilunate fracture dislocations. The mechanism of injury involves wrist extension, ulnar deviation, and intercarpal supination. Mayfield described the stages of injury progressing from radial to ulnar in type IV dislocation, including disruption of the scapholunate ligament and radioscaphocapitate ligament, disruption of the lunocapitate joint, disruption of the lunotriquetral ligament, dislocation of the lunate from its fossa at the radiocarpal joint volarly into the carpal tunnel, and disruption of the dorsal radiocarpal ligament. The volar location of the lunate implies a rupture of any dorsal attachments. On the posteroanterior view of the x-ray study of the wrist, there will be disruption of Gilula lines. On a lateral x-ray study, a “spilled teacup” sign is seen
A 21-year-old man is evaluated after he fell onto his outstretched hand while snowboarding, resulting in edema and pain of the wrist. On the basis of examination, the plastic surgeon suspects a scapholunate ligament injury. Which of the following is the most appropriate x-ray study for evaluation of the suspected injury, and what finding would be considered abnormal?
The correct response is Option B.
Scapholunate injuries frequently occur following falls onto an outstretched hand or other wrist trauma. Patients may develop pain and edema about the wrist, and physical examination should include a scaphoid shift test. In the setting of a scapholunate injury, lateral views of plain x-ray studies often demonstrate a scapholunate angle greater than 60 degrees (normal range, 30 to 60 degrees), and clenched fist views frequently demonstrate a scapholunate diastasis greater than 2 cm. A scapholunate interval of 1.5 cm is normal, and the scaphocapitate interval is not used for determination of a scapholunate ligament injury. Additional imaging modalities include MRI and diagnostic arthroscopy.
A 27-year-old man is evaluated because of chronic right wrist pain after a motor vehicle collision. X-ray studies show no fractures and normal carpal bone alignment. Watson’s scaphoid shift test is positive. Which of the following modalities offers the highest sensitivity and specificity for the diagnosis of this injury?
A) Anteroposterior x-ray study B) Arthroscopy C) Clenched fist x-ray study D) CT scan E) MR arthrogram
The correct response is Option B.
The correct answer is wrist arthroscopy. Arthroscopy is considered the gold standard for the diagnosis of scapholunate and other intercarpal ligament injuries as the injury is directly visualized. The scapholunate ligament is generally best visualized through the 3,4 portal, and midcarpal joint arthroscopy is also recommended to make the diagnosis. Arthroscopy is the standard that all other modalities are compared against.
Standard x-ray studies should be performed for any patient with suspected wrist pathology. In addition to posteroanterior, lateral, and oblique films, both scaphoid and clenched fist views should be obtained. Dynamic scapholunate instability will have normal x-ray studies, and it can take 3 months or longer to see any evidence of scapholunate instability, such as scapholunate diastasis greater than 3 mm or an increased scapholunate angle greater than 70 degrees.
Noncontrast MRI is a common method of evaluation for intercarpal ligament tears. The accuracy of MRI is improved with a 1.5-T or greater magnet, thin slices, use of a wrist coil, and reading by a fellowship-trained musculoskeletal radiologist. Studies show that MRI is only about 70% sensitive but highly specific (close to 100%) for scapholunate ligament tears.
Arthrography, both conventional CT and MR, can improve the accuracy of imaging. Contrast extravasation to the midcarpal joint is diagnostic of a complete tear but does not examine the extent of the lesion. Arthrography sensitivity and specificity is approximately 95% and 85%, respectively.
A 50-year-old woman with type 2 diabetes mellitus is scheduled to undergo ligament reconstruction tendon interposition (LRTI) surgery for trapeziometacarpal joint arthritis. The procedure is expected to last 90 minutes. Which of the following is the most appropriate antibiotic prophylaxis for this patient?
A) Oral antibiotics for 3 days following surgery
B) Single dose intravenous antibiotic within 1 hour of surgery
C) Single dose intravenous antibiotic within 1 hour of surgery and oral antibiotics for 24 hours following surgery
D) Single dose intravenous antibiotic within 1 hour of surgery and oral antibiotics for 3 days following surgery
E) No antibiotic prophylaxis is indicated
The correct response is Option E.
Multidrug resistant bacterial infections continue to rise and antimicrobial overuse is the leading cause for antibiotic resistance. There is growing evidence that prophylactic antibiotic use is not necessary for clean plastic surgery cases, aside from breast surgery cases. Despite consensus guidelines, the use of prophylactic antibiotics for elective Hand Surgery cases continues to increase. Level I evidence exists that demonstrates prophylactic antibiotics are not necessary for clean Hand Surgery cases lasting less than 2 hours. Although there has been concern regarding diabetes and surgical infection risk, this has not been demonstrated in larger studies with multivariate analyses.
A 29-year-old man undergoes evaluation for nonunion of a scaphoid fracture. Reconstruction with a vascularized osseous flap is planned, and a medial femoral condyle flap is chosen. During harvest, the vascular pedicle for this flap runs between which of the following structures?
A) Anterior to the tensor fascia lata and posterior to the vastus lateralis
B) Anterior to the vastus medialis and anterior to the adductor tendon
C) Anterior to the vastus medialis and posterior to the rectus femoris
D) Posterior to the rectus femoris and anterior to the vastus lateralis
E) Posterior to the vastus medialis and anterior to the adductor tendon
The correct response is Option E.
The medial femoral condyle osseous free flap has become a useful option for reconstruction of bony defects in the extremities, particularly of the scaphoid waist and proximal pole. The vascular supply to this flap is from the descending geniculate artery in the distal medial aspect of the thigh. To explore and identify the pedicle for this flap, the vastus medialis is reflected anteriorly, and the adductor tendon is found posterior to the vessels. The rectus femoris is located anterior to the dissection for this flap.
A 30-year-old man presents to the emergency department with acute left wrist pain after falling 10 feet from a ladder. X-ray studies of the left wrist are shown. After failed closed reduction, the patient reports tingling that progresses to worsening and constant numbness of the left index and long fingers over the course of 6 hours. Which of the following urgent interventions is most appropriate?
A) Aspiration of the wrist
B) Carpal tunnel release
C) MRI of the wrist
D) Open reduction of the scaphoid
E) Repeat closed reduction
The correct response is Option B.
This patient has a type IV perilunate dislocation, or a true lunate dislocation. This represents a complete disruption of the ligamentous stabilizers about the lunate. These injuries are high energy and can be ligamentous only (lesser arc injuries) or include fractures (greater arc) and are then termed perilunate fracture dislocations. Mayfield et al described the stages of injury progressing from radial to ulnar in a type IV dislocation, including injury of the scapholunate ligament, disruption of the lunocapitate joint, injury of the lunotriquetral ligament, and dislocation of the lunate from its fossa at the radiocarpal joint volarly into the carpal tunnel.
On posteroanterior x-ray study of the wrist, there will be disruption of Gilula’s lines. On lateral x-ray study, a “spilled teacup” sign is seen.
Closed reduction with relaxation and traction is important, as the lunate needs to be relocated to its fossa to restore relative alignment of the wrist and to decompress the median nerve in the carpal tunnel. Surgical intervention can then be performed for open reduction of the joints and ligament repair after swelling has improved. However, progression in median nerve symptoms in the setting of successful or failed closed reduction is indicative of acute carpal tunnel syndrome and necessitates urgent surgical intervention.
Advanced imaging such as MRI is not required but may be helpful. Repeat closed reduction is likely to fail at this time, may worsen the swelling, and is unlikely to resolve the carpal tunnel symptoms. Open reduction of the scaphoid is not emergent, and the patient does not have a scaphoid fracture. Aspiration of the wrist will not resolve the inciting etiology of the patient’s carpal tunnel symptoms.
A 28-year-old man sustains acute wrist extension during a fall on an outstretched arm. Examination shows snuffbox tenderness. A scaphoid fracture is suspected. Which of the following imaging studies should be performed first to identify this patient’s injury?
A) Bone scan
B) CT scan
C) MRI
D) Plain x-ray studies
E) Ultrasonography
The correct response is Option D.
The correct answer is plain x-rays. Negative x-rays in scaphoid fractures are up to 30%. Cost effectiveness of obtaining x-rays first is shown by the positive finding in 70%. The predictive value of clinical examination is 13-69% with an average of 21%. Depending on clinical suspicion and whether the patient needs to avoid immobilization if the absence of fracture can be confirmed, additional imaging studies may be obtained.
For MRI, the estimated sensitivity is 97.7% and the specificity is 99.8% with 96% accuracy. For a CT scan, estimated sensitivity is 85.2 to 94% and the specificity is 96 to 99.5% with 98% accuracy. Bone scintigraphy is 96 to 97.8% and 89 to 93.5%, respectively, with 93% accuracy. For follow-up x-ray studies, 91.1 and 99.8%, respectively. MRI is therefore the best test for ruling in scaphoid fractures where the other tests are better at ruling out scaphoid fractures. Cost effectiveness of MRI for patients with suspicion for scaphoid fracture with negative x-rays is shown by getting patients out of unnecessary splints sooner.
A 71-year-old woman elects to undergo surgery for basal thumb osteoarthritis. In addition to carpal tunnel syndrome and presence of pathology at the scaphotrapeziotrapezoid (STT) joint, assessment for which of the following additional concomitant conditions is most appropriate during the operative planning for this patient?
A) Lunotriquetral dissociation
B) Radioscaphoid arthritis
C) Scapholunate dissociation
D) Thumb interphalangeal arthritis
E) Thumb metacarpophalangeal hyperextension
The correct response is Option E.
Operative planning for surgical treatment of basal thumb osteoarthritis requires not only careful history, physical examination, and radiographic examination of the basal thumb joint, but also the scaphotrapeziotrapezoid (STT) joint, the carpal tunnel, and the thumb metacarpophalangeal (MP) joint. Persistent arthritic symptoms following treatment of the basal thumb joint are often due to unrecognized STT arthritis, and many patients will have carpal tunnel syndrome concomitant with basal thumb arthritis; thus, it is important to evaluate for these pathologies to avoid persistent symptoms following surgery. The MP joint must be evaluated for collapse, or hyperextension, particularly with pinch prior to operative treatment. Failure to correct MP hyperextension, particularly that beyond 30 degrees, may lead to persistent pain and progressive collapse of the thumb.
The scapholunate, lunotriquetral, thumb interphalangeal, and radioscaphoid joints are not associated with basal thumb arthritis or its treatment.
A 47-year-old woman comes to the office after sustaining an injury to the left wrist after falling on her outstretched hand. Examination shows pain of the radial aspect of the left wrist and anatomical snuffbox. Scaphoid fracture is suspected. When obtaining posterior-anterior x-ray studies, which of the following is the optimal positioning of the wrist for evaluation of the entire scaphoid?
A) Wrist in 20 degrees of radial deviation, 20 degrees of wrist extension
B) Wrist in 20 degrees of radial deviation, 20 degrees of wrist flexion
C) Wrist in 20 degrees of ulnar deviation, 20 degrees of wrist extension
D) Wrist in 20 degrees of ulnar deviation, 20 degrees of wrist flexion
E) Wrist in neutral radial/ulnar position, neutral flexion/extension
The correct response is Option C.
Scaphoid fractures are the most common carpal fracture and frequently occur after a fall onto an extended and radially deviated wrist. Initial workup often involves plain x-ray studies, which have a sensitivity of approximately 85%. The optimal position of the wrist when imaging scaphoid fractures includes ulnar deviation and wrist extension, which allows for evaluation of the long axis of the scaphoid. CT scan or MRI may be used as additional imaging if plain x-ray studies do not demonstrate a fracture, yet there is high clinical suspicion.
A 24-year-old man is scheduled to undergo reconstruction for avascular necrosis of the proximal pole of the scaphoid with a free osteochondral bone flap. Which of the following arteries is the most commonly encountered vascular pedicle for the medial femoral condyle free bone flap?
A) Anterior tibial recurrent
B) Descending genicular
C) Popliteal
D) Saphenous
E) Superficial femoral
The correct response is Option B.
The medial femoral condyle free bone (corticocancellous) flap has been shown to be an excellent option for treatment of complicated degenerative bone pathology in the wrist, particularly scaphoid avascular necrosis. The Mayo group has also shown improved outcomes for scaphoid nonunion with humpback deformity compared with pedicled flaps from the distal radius. The same group has shown more consistent presence of supply from the medial superior genicular artery, which can be used in cases where the descending genicular artery is insufficient, although the pedicle length of the medial superior genicular artery is generally shorter. More recent anatomic analysis has shown this vessel can supply flaps up to 11 cm in length.
The (superficial) femoral and popliteal arteries are larger, regional vessels, with the superficial femoral artery being the immediate source vessel for the descending genicular artery. The popliteal artery is the source vessel for the medial superior genicular artery. The anterior tibial recurrent artery is distal and lateral, lying over the lateral aspect of the tibial plateau, and does not supply the medial femoral condyle. The saphenous artery has been described as a branch of the superficial femoral supplying the skin paddle overlying the medial femoral condyle but does not supply the bone.
A 32-year-old man presents following a motor vehicle collision in which he sustained a dorsal perilunate dislocation of the nondominant left hand. He was treated with open reduction and internal fixation including ligament repair with suture anchors and Kirschner-wires two days after the injury. Which of the following is the expected long-term outcome for this patient?
A) Chronic pain and grip strength less than 50% of the normal side
B) Evidence of moderate post-traumatic arthritis and 80% of grip strength compared to the opposite side
C) Normal x-ray appearance with greater than 80% of motion compared with the opposite side
D) Normal x-ray appearance with poor wrist motion and poor grip strength
E) Severe post-traumatic arthritis requiring total wrist fusion
The correct response is Option B.
Peri-lunate dislocations (PLD) and peri-lunate fracture dislocations (PLFD) are considered complex, high-energy injuries with potentially difficult recovery for many patients. In terms of outcomes research, long-term data are considered to be follow-up greater than 10 years. The long-term data are retrospective but consistent across many studies.
The treatment of choice for PLD and PLFD is open reduction and internal fixation. Studies looking at closed reduction and casting or percutaneous pin fixation have shown inferior outcomes, and open treatment is recommend by most authors.
All studies agree that there will be the presence of moderate or even severe post-traumatic arthritic changes on x-ray in most patients (50 to 100%), which can be various degrees of SLAC, SNAC, or avascular necrosis. However, the data also show that the presence of radiographic arthritis does not necessarily correlate with functional outcomes. On average, patients will achieve 65 to 70% of wrist flexion-extension arc and 80% grip strength compared with the unaffected side.
Although some patients may develop severe complications of a PLD or PLFD such as advanced SLAC or SNAC or ulnar translation of the carpus, it is a rare finding. Most studies show outcomes in the good and fair range according to the Mayo wrist score and other outcome measures. Patients with the most severe arthritis usually do correspond to the worst symptoms and may require salvage procedures such as proximal row carpectomy or limited wrist fusion.
Persistent, chronic pain is a rare finding with long-term outcomes of perilunate injuries. Pain with heavy activity only is the most commonly reported outcome, although many patients are largely pain free.
Patients can have near normal looking x-rays after PLD or PLFD; however, this is rare. One would not expect >80% of wrist motion after an injury of this magnitude even with normal x-rays. Also, patients with minimal arthritic changes tend to show better functional outcomes.
A 23-year-old man who works in an office undergoes evaluation of the left nondominant wrist after sustaining an injury from a fall 2 days ago. CT scan shows a nondisplaced distal scaphoid tubercle fracture. Examination reveals no other abnormalities. Which of the following is the most appropriate next step in management?
A) Autologous bone grafting and internal fixation plus immobilization for 3 to 6 months
B) Cast immobilization for 6 to 8 weeks
C) Compression screw fixation plus immobilization for 6 to 12 weeks
D) Physical therapy for 6 weeks
E) Observation until the wrist is nontender
The correct response is Option B.
Nondisplaced scaphoid fractures may not be apparent on plain radiographs and are better visualized on CT scan. Although the treatment options for nondisplaced scaphoid wrist fractures may include immobilization alone or surgical fixation, nondisplaced distal pole and tubercle fractures are felt to be more stable and can be treated with immobilization alone for 6 to 12 weeks. In addition, these fractures often have small fragments that are not as amenable to compression screw fixation.
Observation and physical therapy allow mobilization of the wrist and are not recommended because of the potential for delayed healing or nonunion.
Compression screw fixation is not generally necessary and is sometimes not possible for tubercle fractures, but it is a common treatment for scaphoid wrist fractures.
Autologous bone grafting and internal fixation is generally reserved for scaphoid nonunions.
When considering dislocations of the thumb carpometacarpal (CMC) joint, which of the following is most correct regarding which vector of dislocation would occur with injury to the stabilizing ligament?
Injured Ligament Vector of Dislocation
A)Dorsal intercarpal radial
B)Dorsoradial dorsal
C)Intermetacarpal ulnar
D)Radiocarpal dorsal
The correct response is Option B.
The CMCJ is very important for hand function and plays a key role in pinch and grasp. The increased range of motion inherent to the thumb CMCJ is attributed to the anatomy of the joint. The biconcave saddle shaped articular surface of the CMCJ also provides some inherent stability. Motion allowed by the joint includes flexion, extension, adduction, abduction, circumduction. Stabilizing ligaments and joint capsule further reinforce the joint, thus thumb CMCJ dislocations are rare injuries. These injuries account for less than 1% of hand injuries.
There are five major stabilizing ligaments to the CMCJ: anterior (volar) oblique, ulnar collateral, intermetacarpal, dorsoradial, and dorsal (posterior) oblique. These ligaments are critical stabilizers during motion. The volar oblique ligament and dorsoradial ligaments are considered to be the most important resistive forces in dislocation in cadaver studies. Reports of traumatic thumb CMCJ dislocation have been in a dorsal vector. The volar oblique ligament was originally thought to be the critical resistive ligament; however, recent literature has supported the dorsal complex (includes the dorsoradial and posterior oblique ligaments) are the most critical for restraint of the joint, thus are injured in dorsal dislocations. Timely recognition is important for these injuries as immediate reduction and casting or splinting for 4 to 6 weeks may be adequate to prevent recurrence. However, these injuries are often missed on radiologic examination or may be persistently unstable. Closed reduction and Kirschner wire fixation may be adequate for treatment in persistently unstable injuries. Some authors advocate for open reduction and ligament reconstruction. Delayed treatment especially beyond three weeks will likely require open reduction and ligament reconstruction. These injuries are often missed on x-ray examination as they can be subtle especially in the setting of more obvious trauma. Inadequate treatment puts these patients at increased risk for subsequent posttraumatic osteoarthritis given the joint malalignment.
The radiocarpal and dorsal intercarpal ligaments are wrist stabilizer not thumb CMCJ stabilizers.
A 36-year-old man comes to the office because of a 2-week history of pain of the right wrist after a fall on his outstretched hand. X-ray studies are shown. If this injury is left untreated, which of the following joint surfaces is most likely to develop arthritis first?
A) Capitolunate
B) Lunotriquetral
C) Radiolunate
D) Radioscaphoid
E) Scaphocapitate
The correct response is Option D.
The most likely joint surface to develop arthritis is the radioscaphoid joint. This patient shows evidence of scapholunate ligament tear. There is evidence of widening of the scapholunate interval and increase in the scapholunate angle.
The scapholunate angle is calculated by measuring the angle between a line drawn perpendicular to the distal surface of the lunate and along the axis of the scaphoid on the lateral view. The normal scapholunate angle varies from 30 to 60 degrees. A tear in the scapholunate ligament results in volar flexion of the scaphoid bone and dorsiflexion of the lunate, with a resultant increase in the angle.
If a scapholunate ligament tear is left untreated, a degenerative pattern of changes result. This is known as scapholunate advanced collapse (SLAC) wrist. Over time there is separation of the scaphoid and lunate bones and descent of the capitate into the intervening space.
With scapholunate ligament tears, arthritis occurs in a predictable sequence. This initially begins in the radioscaphoid joint, followed by the scaphocapitate joint and the capitolunate joint. The radiolunate joint is typically spared until advanced stages. The lunotriquetral ligament is intact and arthritis does not occur in this area with SLAC wrist.
In patients with basilar joint arthritis of the thumb, treatment with trapeziectomy alone compared with trapeziectomy with ligament reconstruction and tendon interposition is most likely to result in which of the following?
A) Decreased complication rate
B) Increased risk for recurrent pain
C) Longer recovery time
D) Worse functional outcomes
The correct response is Option A.
Simple trapeziectomy was first described in 1947 and though it is only utilized by a small minority of hand surgeons in the United States as solitary treatment for basilar thumb arthritis, its efficacy has not been demonstrated to be inferior to the more commonly employed trapeziectomy with ligament reconstruction and tendon interposition. Meta-analysis has demonstrated that simple trapeziectomy is equally beneficial in terms of pain relief and function as trapeziectomy with ligament reconstruction and tendon interposition, but results in fewer complications.
A variety of reconstructive techniques have been employed in management of basilar thumb arthritis. Most commonly employed in the United States is the trapeziectomy with ligament reconstruction and tendon interposition utilizing the flexor carpi radialis tendon. Other described techniques include CMC joint implant arthroplasty, partial trapeziectomy with interposition arthroplasty, and thumb metacarpal extension osteotomy for early-stage arthritis. None of these techniques have demonstrated superiority over simple trapeziectomy, and synthetic implants have been associated with significant complications.
A 53-year-old man comes to the office because of a 2-year history of increasing pain of the radial aspect of the right wrist. X-ray studies show scapholunate disruption and arthritis. Which of the following joints is most likely to be affected first by the arthritic degeneration in this patient?
A) Capitolunate
B) Radiolunate
C) Radioscaphoid
D) Radioulnar
E) Scaphotrapezio
The correct response is Option C.
This patient has early-stage scapholunate advanced collapse (SLAC) wrist. SLAC wrist is generally categorized by the Watson classification, which is a descriptive classification but also helps determine management options.
The Watson classification is as follows:
Stage I: Arthritis between scaphoid and radial styloid
Stage II: Arthritis between scaphoid and entire scaphoid facet of the radius
Stage III: Arthritis between capitate and lunate
While original Watson classification describes preservation of radiolunate joint in all stages of SLAC wrist, subsequent description by other surgeons of pancarpal arthritis (stage IV) observed rare cases in which the radiolunate joint is affected. The radioulnar joint is not affected by SLAC wrist.
A 20-year-old woman comes to the office for evaluation of chronic pain of the right wrist, which is alleviated by nonsteroidal anti-inflammatory drugs (NSAIDs). Osteoid osteoma is suspected on x-ray. Which of the following imaging studies is most likely to confirm the suspected diagnosis?
A) Bone scan
B) CT scan
C) Laser fluorescence angiography
D) Magnetic resonance arthrography
E) Ultrasonography
The correct response is Option B.
Osteoid osteoma is a benign bone tumor that arises from osteoblasts; the principal symptom is focal pain at the site of the lesion.
Multiple studies suggest that CT is the best imaging technique for detection of this tumor. Specifically, CT is best at depicting the nidus, the radiolucent area typical of this tumor type. Within the radiolucent nidus, a central area of high attenuation is often seen, representing mineralized osteoid.
As ultrasound waves do not adequately penetrate bone, this intracortical lesion would not easily be detected by this technique.
Although magnetic resonance (MR) has been used to detect these lesions, it is not as sensitive at detecting the nidus as CT scanning. This is because the nidus, especially if it is small, will have signal similar to cortical bone on MR. Although an arthrogram may detect an intra-articular osteoid osteoma, this is a more unusual entity.
A bone scan may show the lesion, but it is nonspecific and will not confirm the diagnosis.
Laser fluorescence angiography has gained popularity for assessing the perfusion of soft tissues (skin, flaps, etc.), but this technique will not help assess bone or tissues of significant depth, nor can it reliably distinguish tumor from other tissue.
A 19-year-old man comes to the office because of persistent left wrist pain after an ATV accident 4 months ago. Medical history includes cast treatment of a wrist fracture. X-ray study shows a proximal pole scaphoid fracture without arthritic changes or collapse. Which of the following is the most appropriate imaging for assessing the vascularity of the bone fragment in this patient?
A) Angiography
B) CT scan
C) MRI
D) Triple phase bone scan
E) Ultrasonography
The correct response is Option C.
The most appropriate imaging modality is MRI.
This patient has presented with a delayed proximal pole scaphoid fracture/nonunion, which was previously untreated. The primary blood supply to the scaphoid enters distally and travels proximally. As a result, perfusion to the proximal portion of the scaphoid occurs in a retrograde fashion. Fractures of the proximal pole of the scaphoid are located at the furthest distance from the blood supply, and these fragments are at risk for nonunion and avascular necrosis.
MRI (particularly with gadolinium enhancement) would be the best imaging study for evaluating the blood supply to the scaphoid fragment and looking for the presence of avascular necrosis. MRI can also provide anatomical information regarding the fracture. Direct intraoperative visualization of bleeding of the fragment has also been advocated in assessing vascularity.
Angiography can show blood flow patterns, but would not provide anatomic information.
CT scan is useful for detailed anatomic analysis of fractures and assessment of healing, but would be less helpful than MRI in determining avascular necrosis.
Bone scan shows the presence of inflammatory activity and can be used in identifying the presence of occult fractures (high sensitivity, albeit with low specificity), but has low resolution and would not be helpful in determining avascular necrosis.
Ultrasonography has been used in the diagnosis of acute fractures, but would not determine vascularity.
A 40-year-old man comes to the office for evaluation of a nonhealing scaphoid fracture. History includes bone grafting for avascular necrosis of the proximal pole, but there is evidence of nonunion. Carpal collapse and humpback deformity are also noted. Reconstruction with a vascularized medial femoral condyle flap is scheduled. Which of the following arteries provides the blood supply to this flap?
A) Descending genicular artery
B) Lateral circumflex femoral artery
C) Medial circumflex femoral artery
D) Peroneal artery
E) Profunda femoris artery
The correct response is Option A.
The descending genicular artery supplies the medial femoral condyle flap. The descending genicular artery is a branch of the superficial femoral artery. This corticoperiosteal flap has been used with increasing frequency for small bony defects and the treatment of nonunion. A cutaneous component can also be harvested based on a saphenous artery branch.
The anterolateral thigh flap is based off the lateral femoral circumflex artery perforators. The gracilis muscle flap is based off vessels from the medial circumflex femoral artery; perforator flaps can also be designed based off this vascular system. The profunda femoris supplies the posterior thigh flap. The peroneal artery provides the vascular supply to the fibula flap.
A 30-year-old woman comes to the office because of a mass of the dorsum of the wrist for the past 5 months. She reports that the mass occasionally gets larger and then gets smaller. Physical examination shows the mass is mildly tender and transilluminates. From which of the following articulations is this lesion most likely to arise?
A) Pisotriquetral
B) Radioscaphoid
C) Scapholunate
D) Scaphotrapezial
E) Thumb carpometacarpal (CMC)
The correct response is Option C.
The mass in question is most likely a dorsal ganglion cyst of the wrist. Sixty to 70% of ganglion cysts are found in the dorsal aspect of the wrist. Dorsal wrist ganglion cysts usually communicate with the joint by a stalk. This stalk usually originates at the scapholunate interval, but it can also rarely arise from other aspects of the dorsal wrist joint.
Thirteen to 20% of ganglia are found on the volar aspect of the wrist, and they usually arise from the radioscaphoid, scapholunate, scaphotrapezial, or metacarpotrapezial joint, in decreasing order of frequency.
Ganglia arising from the flexor tendon sheath of the hand account for approximately 10%.
A 36-year-old man undergoes rehabilitation following scapholunate ligament repair. Initial range of motion in therapy is planned to allow wrist movement while minimizing the movement between the scaphoid and lunate bones. Which of the following wrist movements is most likely to achieve this goal?
A) Neutral wrist extension to neutral wrist flexion
B) Radial deviation in extension to radial deviation in flexion
C) Radial deviation in extension to ulnar deviation in flexion
D) Ulnar deviation in extension to radial deviation in flexion
E) Ulnar deviation in extension to ulnar deviation in flexion
The correct response is Option C.
The most appropriate motion is from radial deviation in extension to ulnar deviation in flexion.
The dart-thrower’s motion, moving from radial deviation in extension to ulnar deviation in flexion, minimizes the movement between the scaphoid and lunate.
Studies have shown that during movement in this axis, from radial deviation and extension to ulnar deviation and flexion, the bones of the proximal carpal row (scaphoid, lunate, triquetrum), remain practically stationary, and motion occurs primarily through the midcarpal joint. As a result, this is felt to be the primary mechanical axis of movement in the wrist. Rehabilitation with movement in the dart-thrower’s axis will limit movement between the bones of the proximal carpal row and allow wrist range of motion while minimizing stress on a scapholunate repair.
Simulation of radioscapholunate fusion results in preservation of the dart-thrower’s motion, confirming this concept.
The remaining motions listed result in greater intercarpal movement of the proximal row.
A 65-year-old woman comes to the office because of pain at the base of the right thumb. Which of the following is the most appropriate plain x-ray study view for visualizing thumb basal joint subluxation?
A) Bett view
B) Brewerton view
C) Eaton stress view
D) Roberts view
E) Standard lateral view of the thumb
The correct response is Option C.
The Eaton stress view is done with the radial borders of the thumb distal phalanges pressed together. It is a posteroanterior view and assesses laxity of the basal joint as demonstrated by subluxation of the thumb metacarpal on the trapezium.
The Brewerton view is taken with the fingers flat on the x-ray plate with the metacarpophalangeal joints flexed 65 degrees beam angled from a point 15 degrees to the ulnar side of the hand. It shows the metacarpal head and is useful for demonstrating degenerative disease or occult fractures.
Bett (or Gedda) view is characterized as a true lateral view of the trapeziometacarpal joint, perpendicular to the plane of the hand. It is performed as a posteroanterior view, with the hand pronated 30 degrees and the axis of the imaging tube angled 25 degrees distally. The view isolates the trapeziometacarpal joint and is useful for evaluating metacarpal base fractures (Bennett’s fracture).
Roberts view is done with the wrist hyper-pronated and the dorsum of the thumb flat on the plate with an AP view. It is used to evaluate degeneration of the trapeziometacarpal joint but does not show subluxation as the stress view does.
A 23-year-old man comes for evaluation because of pain and swelling of the left wrist 6 hours after he fell onto his outstretched left hand. On physical examination, he has tenderness to palpation in the anatomical snuffbox. An occult fracture is suspected. In addition to standard x-ray study views of the wrist, which of the following x-ray views is the most appropriate to confirm the diagnosis?
A) Anteroposterior view with neutral alignment and the beam angled at neutral
B) Clenched fist view with the wrist at neutral and the beam angled at 30 degrees distal to proximal
C) Lateral view with the wrist flexed 30 degrees and the beam angled 45 degrees distal to proximal
D) Oblique view with radial deviation and the beam angled at neutral
E) Posteroanterior view with ulnar deviation and the beam angled 20 degrees distal to proximal
The correct response is Option E.
The scaphoid oblique view is a posteroanterior (PA) view with the wrist in ulnar deviation and the beam angled 20 degrees distal to proximal. This view often will show scaphoid fractures not seen on standard PA, oblique, or lateral views. The other views would not extend the scaphoid and the scaphoid would not be seen as clearly.
A 59-year-old woman comes for evaluation because of a 7-month history of pain over the radial aspect of the right wrist that is aggravated with forceful gripping. She denies any history of trauma to the hand or wrist. On physical examination, there is tenderness to palpation over the right anatomic snuffbox and thenar eminence. Axial load and shifting of the basal joint does not result in crepitance or pain. Resisted thumb extension at the metacarpophalangeal joint level is not painful. An x-ray study of the wrist is shown. Which of the following is the most appropriate operative management?
A) Arthrodesis of the scaphotrapeziotrapezoid joint
B) Arthrodesis of the trapeziometacarpal joint
C) Hemi-resection of the distal trapezium and tendon interposition
D) Release of the first dorsal compartment
E) Release of the second dorsal compartment
The correct response is Option A.
Scaphotrapeziotrapezoid (STT) arthritis can often be misdiagnosed on initial presentation as basal joint arthritis. The keys to differentiating the two sites of pain include physical examination, which shows tenderness more proximal than the basal joint and absence of pain with a grind maneuver, coupled with imaging showing osteoarthritic degeneration at the STT rather than the trapeziometacarpal level. Treatment for the arthritic pain can consist of resection arthroplasty or arthrodesis. Both techniques can provide good relief of symptoms. Resection arthroplasty often is used when the scapho-trapezoid articulation is relatively preserved. Regardless of technique chosen, the surgeon should address both the scapho-trapezial and the scapho-trapezoid joints during the procedure.
Release of the first dorsal compartment would address de Quervain tenosynovitis, which could present with pain over the anatomic snuffbox. On examination, however, the patient would typically demonstrate pain with the “resisted Hitchhiker” maneuver (resisted extensor pollicis brevis function at the metacarpophalangeal level). Given the negative findings on examination and the STT arthritis noted on imaging, this patient would not likely respond to treatment directed at the first dorsal compartment.
Second dorsal compartment tenosynovitis can present with distal forearm and wrist pain. The location of the pain is typically more proximal in the forearm and localized to the intersection between the muscle bellies of the first compartment tendons and the radial wrist extensors. This patient’s pain is localized to the STT region rather than the second dorsal compartment.
Hemiresection of the distal trapezium and tendon interposition has been used successfully in the management of trapezio-metacarpal arthritis (basal joint arthritis). In this patient, the location of the pain, absence of pain with a “grinding” type maneuver, and the imaging showing preservation of the basal joint argue against directing treatment at the basal joint itself.
For the same reasons that hemiresection of the distal trapezium is a poor choice for this patient, arthrodesis of the basal joint addresses the wrong site of arthritis. X-ray study and physical examination both indicate STT arthritis as the etiology of the patient’s pain.
A 20-year-old man is evaluated after falling on his outstretched hand. Physical examination shows tenderness of the snuffbox. X-ray studies of the wrist show no fracture. Which of the following is the most appropriate initial step in management?
A) Application of a sugar-tong splint
B) Application of a thumb spica splint
C) Application of a volar wrist splint
D) Application of an ulnar gutter splint
E) No treatment is necessary
The correct response is Option B.
The patient described may have a scaphoid fracture that is not apparent on initial x-ray studies. Prudent management involves placement of a thumb spica splint until definitive diagnosis can be made. Repeating x-ray studies in 2 weeks or obtaining further radiologic studies, such as CT scans, can make the definitive diagnosis. Casting would be suboptimal in an acute injury such as this because soft-tissue swelling can cause constriction. Surgical exploration is not warranted at this time. A wrist-control, sugar-tong, or ulnar gutter splint would not adequately immobilize the scaphoid, and therefore, would not be adequate management.
Acute scaphoid fractures can often be missed on initial x-ray studies, with reported sensitivities ranging from 84 to 98%. When clinical suspicion of a scaphoid fracture is high and plain films are negative, the traditional recommendation is for these patients to be immobilized in a thumb spica splint or cast with repeat x-ray studies after about 2 weeks.
Even on the repeated x-ray study after 10 to 14 days propagated by many clinicians in cases of occult fracture, a scaphoid fracture is often missed since the additional sensitivity is low, although in a case of sclerosis, an x-ray study could confirm the suspected diagnosis. Further studies that may confirm the diagnosis include CT scan, MRI, and bone scan.
A 24-year-old man comes to the office because of a scaphoid wrist nonunion with apex dorsal angulation and proximal pole avascular necrosis. A free tissue transfer from the lower extremity is planned. A branch of which of the following arteries supplies the most appropriate flap for this patient?
A) Dorsalis pedis
B) Genicular
C) Lateral femoral circumflex
D) Medial sural
E) Peroneal
The correct response is Option B.
The descending genicular artery is the arterial pedicle for the medial femoral condyle free vascularized osseous corticoperiosteal free flap, or free vascularized bone graft. Scaphoid nonunions with a humpback deformity, carpal collapse, and proximal pole osteonecrosis are difficult to treat. Vascularized bone grafts have been shown to have nearly 2× the union rate of traditional nonvascularized bone grafts. Vascularized corticocancellous bone has the potential to revascularize necrotic bone and can provide structural support for fractures with loss of height of the scaphoid. Studies have shown superior union rates for the medial femoral condyle vascularized bone graft versus pedicled grafts from the distal radius. Anatomical studies show no clinical loss of stability of the femur after flap harvest.
The peroneal artery is the blood supply of the fibular osseous or osteocutaneous free flap. It is generally reserved for head and neck reconstruction and larger defects of the extremities.
The descending branch of the lateral femoral circumflex artery supplies the anterolateral thigh free flap. The dorsalis pedis artery supplies the dorsalis pedis fasciocutaneous flap. The medial sural artery and its perforators supply the medial gastrocnemius muscle, and musculocutaneous and fasciocutaneous flaps. All of these flaps are used for soft-tissue defects alone and are not appropriate for reconstruction of bony defects.
A 39-year-old man comes to the office 3 months after falling 10 feet from a ladder because of persistent radial-sided wrist pain, swelling, decreased grip strength, and a painful clicking in the wrist with moderate activity. Physical examination shows diffuse tenderness of the radial wrist and a painful “clunk” when palpating the scaphoid during radial deviation of the wrist. Initial x-ray studies showed no fracture or dislocation. Recent standard x-ray studies of the wrist show no fracture and normal carpal bone alignment. Which of the following is the most likely diagnosis?
A) de Quervain tenosynovitis
B) Dynamic scapholunate instability
C) Flexor carpi radialis tendinitis
D) Kienböck disease
E) Occult scaphoid fracture
The correct response is Option B.
This patient has dynamic scapholunate instability. These injuries can be difficult to diagnose and require a high index of suspicion. A normal x-ray study at 12 weeks in the setting of these clinical findings suggests there is a disruption of the scapholunate interosseous ligament (SLIL) that is symptomatic only with mechanical loading.
The SLIL is the primary stabilizer of the scapholunate joint, but it is surrounded by multiple secondary stabilizers consisting of the extrinsic wrist ligaments. Normal kinematic motion of the proximal carpal row is controlled by the tough interosseous ligaments. The dorsal component of the SLIL is the primary restraint to distraction, torsion, and translational forces. Disruption of the dorsal SLIL alone will result in changes in wrist mechanics, but the presence of the intact secondary stabilizing ligaments will prevent changes seen on a normal static x-ray study, such as scapholunate dissociation or an increased scapholunate angle.
Stress view x-ray studies, such as the clenched-pencil view, should be obtained when dynamic instability is suspected in the setting of a normal static x-ray study series. These results can be compared with the contralateral normal side. Non-contrast MRI is an advanced imaging modality averaging 71% sensitivity, 88% specificity, and 84% accuracy for SLIL tears. There is improved accuracy with 3.0T MRI machines. Wrist arthroscopy is the gold standard for diagnosis and can be combined with therapeutic procedures such as debridement or thermal shrinkage.
An occult scaphoid fracture should be visible at 12 weeks following the injury. Bone resorption at the fracture site makes the fracture line generally visible within 14 days. If suspicion remains for an occult scaphoid fracture at 2 weeks, additional imaging such as MRI or CT scan is indicated. At 3 months following the injury, any fracture present should be visible and treated as a non-union of the scaphoid.
De Quervain tenosynovitis is defined as tendinitis of the first dorsal extensor compartment. This condition generally presents with pain and tenderness over the radial styloid with a positive Finkelstein test. Tenderness of the carpal bones and carpal bone instability such as a painful “clunk” would not be present. The condition is most associated with repetitive use and not acute trauma.
Kienböck disease involves collapse of the lunate due to vascular insufficiency and avascular necrosis. Etiology is unknown but may involve a combination of anatomic factors and trauma. Early symptoms are similar to a wrist sprain but involve more global wrist pain, loss of dorsiflexion, and tenderness of the dorsal wrist over the lunate. Early stage I disease can have normal x-ray studies but will often show signs of a lunate fracture. Later stage disease shows sclerosis and ultimately fracture or collapse of the lunate.
Flexor carpi radialis (FCR) tendinitis is not a common diagnosis. It presents with wrist pain, crepitus, and point tenderness over the FCR at the wrist flexion crease with flexion and radial deviation. Although it is a cause of radial-sided wrist pain, findings of carpal bone instability on examination are not present.
A 38-year-old man comes to the office because of central wrist pain 7 months after falling on his outstretched right hand. He did not seek treatment at the time of his original injury. An anteroposterior x-ray study is shown. In a lateral x-ray study view, the scapholunate angle is most likely to be which of the following?
A) Less than 20 degrees
B) 20 to 40 degrees
C) 41 to 60 degrees
D) Greater than 60 degrees
The correct response is Option D.
The patient described has scapholunate separation that results not only in widening of the gap between the scaphoid and the lunate, as depicted in the x-ray study shown (Terry-Thomas sign), but also in flexion of the scaphoid. This is seen on the anteroposterior x-ray study as a ?ring sign? as a result of the distal pole of the scaphoid moving relatively closer to the proximal scaphoid cortex and being viewed end-on.
Carpal bone malalignment is also determined by angles on lateral x-ray studies. As the scaphoid flexes progressively, the lunate (still tethered to the triquetrum) goes into an extension dorsal intercalated segment instability deformity.
In a patient with rotary subluxation at the scaphoid, the scapholunate angle is expected to be increased on lateral x-ray study. Normal values range from 30 to 60 degrees. Angles greater than 80 degrees are considered a definite indication of scapholunate dissociation.
A 37-year-old man who works as a carpenter is brought to the emergency department after falling 10 ft from a scaffold. He says he has pain in the left wrist and numbness of the thumb, index, and long fingers of the left hand. Trauma screening shows no other injury, and x-ray studies of the left wrist are obtained (shown). Which of the following is the most appropriate treatment?
A ) Application of finger traps and placement in traction
B ) Closed reduction and carpal tunnel release
C ) Open reduction and internal fixation
D ) Splinting of the wrist in 30 degrees of extension
E ) Total wrist fusion
The correct response is Option C.
Perilunate dislocations are relatively uncommon injuries that typically follow high-energy impact to the wrist. The pattern of injury traverses both the greater and lesser carpal arcs, disrupting the lunotriquetral ligament and either the scapholunate ligament or the body of the scaphoid (trans-scaphoid, perilunate dislocation). Although controversy surrounding the need for operative intervention existed in the past, poor long-term outcomes from closed reduction alone have showed the importance of early restoration of carpal alignment with repair of the injured ligaments. In the setting of trans-scaphoid, perilunate dislocation, this would include rigid internal fixation of the scaphoid.
Application of finger traps and placement in traction may assist in reduction of the dislocated lunate but will not, by itself, reduce the lunate and remove the need for internal fixation and repair of the injured ligaments.
Proximal row carpectomy and wrist function play a role in long-term salvage of the painful wrist following perilunate dislocations. Only in rare circumstances, such as nonreconstructible fractures of the proximal row bones, should acute proximal row carpectomy be considered.
Splinting of the wrist in extension often provides relief in the setting of idiopathic carpal tunnel syndrome; however, in the setting of lunate dislocation, the presence of the lunate in the carpal tunnel necessitates reduction of the lunate for relief of symptoms.
A 28-year-old man who is an amateur motorcycle stunt driver comes to the emergency department because he has progressively worsening pain and numbness in the left hand three hours after injuring the left wrist in a motorcycle misadventure. Radiographs of the wrist are shown. He has previously fractured both scaphoids in similar accidents. The scaphoid fractures are not united. An operating room is not available for at least six hours. Which of the following is the most appropriate next step in management?
(A) Closed reduction
(B) Contrast arthrogram
(C) Contrast MRI
(D) Injection of corticosteroid into the left wrist
(E) Plaster splinting
The correct response is Option A.
The patient described has a closed right dorsal perilunate, transscaphoid, transulnar styloid fracture-dislocation. In the scenario described, with no immediate operating room availability and with worsening pain and numbness, the most appropriate treatment is closed reduction followed by splinting, which can be performed in the emergency department under conscious sedation. When an operating room becomes available, the injuries to ligament and bone can be open repaired or reconstructed.
The critical element is reduction to alleviate the numbness and pain. Splinting follows successful reduction. None of the other options listed addresses correction of the dislocation. The injection of corticosteroid, arthrogram, and MRI are not required for operative management.
Postoperative radiographs are shown.
An 18-year €‘old man is brought to the emergency department after being involved in a motor vehicle collision in which a car rolled onto his dominant right forearm. Physical examination shows a crush injury to the right forearm. Radiographs show no fractures. Urgent decompression of the hand and forearm and debridement of soft tissue are performed because of rapidly progressive compartment syndrome. A photograph of the patient €™s forearm 10 days after the procedure is shown. Which of the following is the most appropriate next step in management?
(A) Coverage with a random abdominal flap
(B) Coverage with a scapular free flap
(C) Full-thickness skin grafting
(D) Intraoperative skin expansion and closure with a local flap
(E) Split-thickness skin grafting
The correct response is Option E.
Split-thickness skin grafts allow for large defects to be covered with skin that will contract with time. In fasciotomy defects following crush injuries, the extremity remains swollen for an extended time. As the swelling subsides, the split graft will contract. A full-thickness graft would not contract as well and would require a large donor site defect for this sizable area.
Burying the forearm in an abdominal flap would yield a very bulky forearm and prevent physical therapy to the extremity while it is attached to the abdomen.
A free flap is unnecessary, as there are no exposed structures (nerve, tendon, or bone) that require vascularized coverage. Under different circumstances, the scapular free flap provides a fairly large surface area of thin skin.
The defect in the patient described is too large for intraoperative skin expansion and would put the underlying structures under pressure.
A 45-year-old man is brought to the emergency department two hours after sustaining an avulsion injury to the thumb of the dominant right hand while roping a horse. The amputated part (shown) is too badly damaged for replantation. Two hours later, the patient says he has increasing pain in the forearm. On physical examination, firmness of the forearm is noted. Active extension of the fingers is limited to 120 degrees, 60 degrees less than on initial evaluation. Loss of sensation to pinprick over the entire hand is noted. Which of the following is the most appropriate next step in management?
(A) Administration of corticosteroids
(B) Application of cold compresses
(C) Carpal tunnel release
(D) Elevation of the arm
(E) Forearm fasciotomy
The correct response is Option E.
The patient described has a case of impending compartment syndrome. The cardinal signs of evolving compartment syndrome are
$ pain disproportionate to the injury
$ palpably swollen compartments
$ pain on passive stretching of the involved muscles
$ diminished perception of simple touch
$ decreased strength of the involved muscles
$ hypesthesia or anesthesia
A significant amount of forearm hemorrhaging can occur after avulsion injuries such as the one shown in the photograph. The surgeon must suspect compartment syndrome and proceed to surgery. None of the other treatment modality options listed are adequate in light of the severity of symptoms.
A 62 year-old man who is a practicing orthodontist comes to the office because he has had pain in the thumb of the dominant left hand at the level of the trapeziometacarpal (TM) joint for the past year. He has no symptoms in the right hand. On physical examination, grind test of the left thumb is positive. Radiographs of both thumbs are shown. Which of the following interventions involving the left thumb is most appropriate at this time?
(A) Injection of a corticosteroid followed by splinting of the TM joint
(B) Metacarpal extension osteotomy of the TM joint
(C) Partial excision of the trapezium and tissue interposition arthroplasty
(D) Resection of the trapezium followed by silicone implant arthroplasty
(E) Splinting of the TM joint and application of a bone stimulator
The correct response is Option A.
The trapeziometacarpal (TM) joint is frequently affected with osteoarthritis. Arthritis of the trapezium can affect five articulations: TM, trapezium €‘second metacarpal, trapezium €‘trapezoid, scaphotrapezial, and scaphotrapezoidal. When all of these surfaces are involved, the condition is called pantrapezial arthritis. This complex of trapezial articulations is referred to as the basal joint of the thumb.
The key to the scenario described is twofold. The first important fact is that radiographic staging may not relate to symptoms. The second important tenet is that conservative nonoperative therapy such as splinting and injection of corticosteroids should be tried first. If conservative therapy is unsuccessful, then arthroplasty is indicated. The patient described has pantrapezial arthritis in the right basilar joint, but he has no symptoms. Therefore, no intervention is needed. The left basilar joint (the patient €™s dominant hand) is symptomatic, and an initial trial of conservative therapy is indicated. One study found that 70% of patients undergoing conservative therapy were able to avoid surgery in the long term.
The grind test is performed by holding the thumb metacarpal and applying axial compression while rotating the metacarpal in a circular motion. Pain and crepitance indicate a positive result.
Early stages of basal arthritis can be treated with ligament reconstruction. The goal of this operation is reconstruction of the volar beak ligament of the thumb metacarpal and reinforcement of the dorsal ligaments. Metacarpal extension osteotomy is an alternative operation for early basal arthritis. The goal of this operation is to unload the palmar joint surfaces. More advanced stages of basal arthritis require either partial or complete resection of the trapezium. Silicone implant arthroplasty has fallen out of favor because of long-term complications such as implant wear, implant fracture, and subluxation. The most common treatment for advanced pantrapezial arthritis is excision of the trapezium with ligament reconstruction and metacarpal suspension. Hematoma and distraction arthroplasty is excision of the trapezium without tendon interposition. In this technique, Kirschner wires are placed for six weeks to maintain the trapezial space. Bone stimulation does not play a role in the treatment of basilar joint arthritis.
An otherwise healthy 55-year-old woman who works as a secretary comes to the office because she has had increasing pain in the left wrist as well as loss of mobility and impaired function for the past year. Physical examination shows tenderness over the dorsoradial wrist, anatomic snuff box, and scaphoid tuberosity. A radiograph is shown. Which of the following is the most appropriate management?
(A) Dexamethasone injection into the radiocarpal joint and splint
(B) Radioscaphoid arthrodesis
(C) Scapho-trapezio €‘trapezoid arthrodesis
(D) Scaphoidectomy and four €‘corner fusion
(E) Total wrist arthrodesis
The correct response is Option D.
The patient described has scapholunate advanced collapse (SLAC wrist). Components of a SLAC wrist include radioscaphoid, capitolunate, and scaphocapitate arthritis. The capitate wedges itself between the scaphoid and lunate as it slides off the ulnar articular surface of the scaphoid. Typically, the articulation of the lunate with the distal radius is preserved, although there are advanced degenerative changes elsewhere in the wrist.
In the radiograph shown, the radiolunate and the scapho-trapezio €‘trapezoid (STT) joints appear preserved. The STT joint is unlikely to be the source of pain considering the clinical history and the radiographic appearance. Therefore, STT arthrodesis is incorrect. Radioscaphoid arthrodesis is unlikely to relieve all symptoms in this patient because of the presence of multiple other arthritic joints. Injection of dexamethasone into the wrist may provide some relief; however, this is not a long €‘term solution. Total wrist arthrodesis is excellent for control of pain caused by advanced osteoarthritis; however, this pain control comes at the expense of loss of mobility. Because of the preservation of the radiolunate joint, a limited wrist arthrodesis (scaphoidectomy and four €‘corner fusion) is a superior alternative. This is because the arthritic joints can be fused or eliminated while preserving wrist motion. Therefore, total wrist arthrodesis is not the best option.
A 30-year-old man who works as a brick mason comes to the emergency department one hour after he sustained an injury to the right wrist when he fell backward off a 10-foot-high wall. He has severe pain in the wrist as well as numbness in the fingers and thumb. Which of the following is the most appropriate management?
(A) Elevation of the hand and monitoring of compartment pressures with a wick catheter
(B) Carpal tunnel release only
(C) Carpal tunnel release and proximal row carpectomy
(D) Carpal tunnel release and scapholunate arthrodesis
(E) Carpal tunnel release, relocation of the lunate, and repair of the volar radiocarpal ligaments
The correct response is Option E.
This patient has sustained a trans-scaphoid, dorsal perilunate, volar lunate fracture dislocation. In addition to pain in the wrist, this injury often presents with acute carpal tunnel syndrome, which must be recognized promptly and treated emergently. The lunate must be relocated from the carpal canal to the carpus, and the associated hematoma must be evacuated. After the lunate has been relocated, the volar radiocarpal ligaments must be repaired. Correct carpal alignment usually requires dorsal and volar approaches using a Kirschner wire in the lunate to function as a joystick. Reduction and fixation of the scaphoid are also required.
Acute carpal tunnel syndrome indicates ongoing compression and ischemia of the median nerve. Conservative measures such as elevation of the hand and serial measurement of compartment pressures are contraindicated. Proximal row carpectomy and scapholunate arthrodesis are options for treatment of degenerative arthritis of the wrist but should not be used as primary treatment of a fracture dislocation.
A 36-year-old man comes to the office because he has had chronic aching pain in the right wrist for the past four months. Physical examination shows tenderness just distal to Lister €™s tubercle and positive Watson sign. Radiographs are shown. This patient has most likely sustained an injury to which of the following structures?
(A) Dorsal wrist capsule
(B) Ligament of Testut
(C) Lunotriquetral interosseous ligament
(D) Scapholunate interosseous ligament
(E) Triangular fibrocartilage complex
The correct response is Option D.
This patient’s radiocarpal angles suggest scapholunate instability and secondary dorsal intercalated segment instability. Scapholunate instability is a result of an injury to the scapholunate interosseous ligament and is the most common form of wrist instability. The scapholunate interosseous ligament is the primary stabilizer of scaphoid motion in linked carpal motion. A normal scapholunate angle is approximately 46 degrees with a range of 30 to 60 degrees. Scapholunate angles greater than 60 degrees tend to imply a scapholunate interosseous ligament injury, whereas angles less than 30 degrees tend to imply a lunotriquetral interosseous ligament injury.
The radiolunate angle is normally 0 to 11 degrees. The lunate can be thought of as a balanced cup on the lateral radiograph, and its articular surface should point straight vertical. The scaphoid acting through the scapholunate interosseous ligament tends to pull the lunate forward, whereas the lunotriquetral interosseous ligament tends to pull the lunate dorsally. Therefore, an injury to the scapholunate ligament allows the triquetrum to exert an extension force on the lunate, pulling it into a dorsally tipped position, which is referred to as a dorsal intercalated segment instability (DISI) deformity. The scapholunate gap is normally 2 mm; a gap greater than or equal to 3 mm is believed to be abnormal and may or may not be present in cases of scapholunate instability.
The dorsal capsule is believed to be one of several secondary stabilizers of the scaphoid and may or may not be injured in this scenario. The ligament of Testut, also know as the radioscapholunate ligament, and the triangular fibrocartilage complex are not believed to contribute to carpal stability.
A 60-year-old man who is retired comes to the office because he has had pain and stiffness of the left wrist for six months after he sustained a traumatic injury when he fell from a ladder. Radiographs of the wrist are shown. Which of the following is the most appropriate management?
(A) Arthrodesis of the wrist
(B) Dorsal capsulodesis
(C) Open reduction and internal fixation of the scaphoid
(D) Proximal row carpectomy
(E) Surgical repair of the scapholunate
The correct response is Option D.
This patient has sustained an injury to the scapholunate ligament. His injury is not recent, as evidenced by the arthritis that is involving the radiocarpal joint and radial styloid. The radiograph suggests a scapholunate injury because of the widened gap between the scaphoid and lunate bones and the widened scapholunate angle (greater than 60 degrees on lateral view). When patients present early, for example within three months of injury, the scapholunate ligament can be repaired and a dorsal capsulodesis procedure can be performed to strengthen the repair. However, when they present later, especially after developing arthritis, the edges of the scapholunate ligament usually cannot be reapproximated and the pain elicited by the arthritis will not be relieved. A wrist arthrodesis may be an option if the lunate fossa of the radius or capitate head are involved with arthritis. However, in this patient, proximal row carpectomy would be the most appropriate management. Patients who undergo proximal row carpectomy usually recover 70% to 80% grip strength and 50% to 60% range of motion. Most patients who undergo proximal row carpectomy have resolution of pain. The scapholunate ligament can be reconstructed with the flexor carpi radialis tendon, AlloDerm, or bone ligament bone construct, but this is not an alternative in an individual who already has arthritis. The scaphoid has not been fractured; therefore, open reduction and internal fixation is not needed.
Postoperative radiographs are shown.
A 35-year-old man who works as an air traffic controller comes to the office because he has had numbness in the dominant right wrist that has been worsening over the past year. Twenty years ago, the patient sustained an injury to the wrist while playing football. He received no treatment for this injury. A radiograph is shown. Which of the following is the most likely diagnosis?
(A) Kienbock €™s disease
(B) Scaphoid nonunion
(C) Scaphoid nonunion advanced collapse (SNAC wrist)
(D) Scapholunate advanced collapse (SLAC wrist)
(E) Scapho-trapezio-trapezoid (STT) arthritis
The correct response is option B.
Proximal pole scaphoid fractures are at increased risk for devascularization. This is visible radiographically with an un-united fracture line and, potentially, sclerosis or whitening of the proximal pole fragment. Left untreated, there is a near 100% incidence of degenerative joint disease, i.e., scaphoid nonunion advanced collapse (SNAC wrist). However, in this case, the articulations between the radius and scaphoid, scaphoid and capitate, and capitate and lunate are preserved. Therefore, scapholunate advanced collapse (SLAC wrist) and SNAC wrist are incorrect.
SLAC wrist is commonly associated with scapholunate ligament injuries and a dorsal intercalated segmental instability pattern (DISI deformity). In this pattern, the lunate assumes an extended position while the scaphoid flexes. In both SNAC wrist and SLAC wrist, the initial degeneration occurs both in the distal scaphoid and the radial styloid.
Scapho-trapezio-trapezoid (STT) arthritis is incorrect because there are no degenerative joint changes in the STT joint on the radiograph. Kienbock=s disease is avascular necrosis of the lunate which is present on the radiograph.
Treatment of un-united proximal pole function of the scaphoid is difficult. Options include simple compression, fixation with a bone graft or bone flap, and excision with or without tendon in position arthroplasty.
A 54-year-old carpenter comes to the office because he has had worsening pain and increasingly limited range of motion of the dominant right wrist over the past five years. Physical examination shows wrist flexion to 40 degrees and wrist extension to 35 degrees. Radiographs are shown above. Which of the following is the most appropriate management?
(A) Revascularization of the lunate
(B) Proximal row carpectomy
(C) Scaphoid excision with four-corner arthrodesis
(D) Scaphoid-trapezium-trapezoid arthrodesis (triscaphe fusion)
(E) Radioscapholunate arthrodesis
The correct response is Option C.
This patient has a scapholunate advanced collapse (SLAC) pattern of degenerative wrist arthritis. To achieve the goals of pain relief and maintenance (or improvement) of wrist motion, scaphoid excision with arthrodesis of the capitate-lunate-hamate-triquetrum is the treatment of choice. If this patient were not concerned about wrist motion, total wrist arthodesis could be performed.
Revascularization of the lunate is more appropriate for the treatment of Kienbock disease, which is believed to result from microfractures of the lunate that lead to ischemic changes and vascular necrosis.
Proximal row carpectomy will result in the diseased capitate being inserted into the lunate fossa. Resurfacing of the capitate would be required for this to be a viable option.
Neither scaphoid excision alone nor scaphoid-trapezium-trapezoid arthrodesis will treat the diseased capitolunate joint.
Radioscapholunate arthrodesis will also fail to treat the diseased capitolunate joint. This would be a reasonable treatment for joint changes confined to the radiocarpal joint, where the midcarpal joint is normal. If this is done, resection of the distal third of the scaphoid may help minimize impingement and loss of motion in radial deviation and flexion.
40-year-old woman comes to the office because she has pain in the wrist that has been worsening over the past two years. A radiograph of the wrist is shown above. Which of the following tests is most likely to confirm the suspected diagnosis in this patient?
(A) Distal radioulnar shuck
(B) Finkelstein
(C) Phalen
(D) Scaphoid shift
(E) Thumb carpometacarpal grind
The correct response is Option E.
The radiograph shows radial subluxation of the metacarpal of the thumb on the trapezium, osteophytic spurring, sclerosis, and articular irregularities of the joint surfaces. The carpometacarpal grind test differentiates radial subluxation from other common sources of wrist pain. For this maneuver, the thumb ray is loaded axially and rotated, stressing the carpometacarpal (basal) joint. If the joint is significantly diseased, pain that mimics the pain resulting from normal hand movement will be reproduced.
The Finkelstein test is used to identify de Quervain’s tenosynovitis. With this maneuver, the thumb is grasped by the fingers in the palm of the hand, and the wrist is ulnarly deviated. This movement accentuates pain over the first dorsal compartment and indicates the presence of tenosynovitis in this region.
The Phalen test is a common maneuver used to diagnose carpal tunnel syndrome. Numbness, tingling, or pain in the distribution of the median nerve is produced with wrist flexion.
The scaphoid shift test is performed by palpating the area over the scaphoid tuberosity and moving the wrist from an ulnar to a radial direction. The scapholunate ligament becomes stressed as the scaphoid assumes a more vertically oriented position with radial deviation. Pain with this maneuver indicates a scapholunate ligament injury.
The distal radioulnar shuck test is performed by stressing the distal radioulnar joint dorsally and palmarly by moving the radius dorsally and the ulna palmarly, or vice versa. Reproduction of pain by this maneuver indicates possible disease of the triangular fibrocartilage complex or distal radioulnar joint.
A 66-year-old woman with advanced rheumatoid arthritis has 20-degree arc of supination and pronation of the hand. Radiograph is shown above. Which of the following interventions is the most effective method of increasing supination and pronation of this patient’s hand?
(A) Arthrodesis of the scaphotrapeziotrapezoid joint
(B) Darrach resection
(C) Proximal row carpectomy
(D) Repair of the triangular fibrocartilage complex
(E) Scaphoidectomy
The correct response is Option B.
This patient has severe rheumatoid arthritis of the distal radioulnar joint. Disease of this joint gradually inhibits rotation around the axis of the forearm. If the radiohumeral articulation at the elbow is functional, resection of the distal ulna can produce significant improvement in supination and pronation of the forearm and hand.
Darrach resection is a simple surgical procedure that is often combined with other reconstructive surgical procedures in the comprehensive treatment of severe rheumatoid arthritis. Therapy is started almost immediately after surgery. This patient had dramatic improvement in supination and pronation of the forearm amounting to 160 degrees after undergoing Darrach resection. She also underwent metacarpophalangeal joint arthroplasty of the index, long, and ring fingers, centralization of the extensor tendons, transposition of the extensor retinaculum, carpal tunnel release with synovectomy, and arthrodesis of the interphalangeal joint of the thumb.
Arthrodesis of the scaphotrapeziotrapezoid joint, proximal row carpectomy, repair of the triangular fibrocartilage complex, and scaphoidectomy will not improve this patient=s forearm supination and pronation.
Arthrodesis of the scaphotrapeziotrapezoid joint is effective for management of trapezial arthritis. Proximal row carpectomy is most commonly used to alleviate pain and limited motion in patients with scapholunate advanced collapse of the wrist. Repair or debridement of the triangular fibrocartilage complex is often appropriate for patients with pain at the ulnar aspect of the wrist who have documented tears. Scaphoidectomy is often combined with four-corner arthrodesis of the capitate, hamate, triquetrum, and lunate to manage scapholunate advanced collapse of the wrist.
The radiographs shown on page 140 are from a 45-year-old dock worker who has had worsening pain and loss of motion and strength in the dominant right wrist over the past two years. Which of the following is the most appropriate operative procedure?
(A) Scapholunate ligament repair
(B) Radial styloidectomy
(C) Radial corrective osteotomy
(D) Ulnar shortening osteotomy
(E) Four-corner arthrodesis
The correct response is Option E.
This patient has scapholunate advanced collapse of the wrist, also known as SLAC wrist, with radioscaphoid arthrosis and a dorsiflexed intercalated segment instability deformity. This condition is caused by incompetency of the scapholunate ligament, which leads to rotatory subluxation of the scaphoid.
SLAC is the most common cause of degenerative arthritis of the wrist. This condition can be classified according to four stages, as shown in the table below.
Stage I Radioscaphoid
Stage II Radial midcarpal
Stage III Ulnar midcarpal
Stage IV Pancarpal
Surgical management is aimed at decreasing pain and optimizing wrist function, using two unaffected articular surfaces if possible. In this patient, goals of surgery include eliminating the radioscaphoid articulation and stabilizing carpal kinematics. Therefore, the most appropriate procedure is scaphoid excision and four-corner arthrodesis between the lunate, capitate, hamate, and triquetrum. None of the other procedures addresses all of the problems that are present in this patient’s wrist.
A 45-year-old roofer has pain and swelling of the right wrist after falling off a roof and landing on his outstretched right hand. Radiographs are shown above. This patient most likely has which of the following types of fracture-dislocation?
(A) Carpometacarpal joint-hamate
(B) Radial styloid
(C) Scaphocapitate
(D) Scaphoid-perilunate
(E) Scaphotrapeziotrapezoid
The correct response is Option D.
This patient has a scaphoid-perilunate fracture-dislocation, also known as a scaphoid-dorsal perilunate fracture-dislocation. Wrist dislocations can range from simple injuries to extended fractures associated with dislocation of one or more carpal bones. This patient has sustained one of the most severe forms of wrist dislocation, as shown in the radiographs.
Fracture-dislocations of the wrist are identified according to the carpal bone(s) involved and the type of lunate dislocation (ie, incomplete or complete). Lunate dislocations are subdivided into midcarpal lunocapitate, complete lunate, and perilunate injuries. A complete lunate injury can be differentiated from a perilunate injury by the presence of a concomitant dislocation of the radiolunate joint. Greater arc injuries are typically caused by high-energy trauma. The radial styloid, scaphoid, capitate, hamate, triquetrum, and/or ulnar styloid may be fractured. Lesser arc dislocations involve injury to the scapholunate, lunocapitate, and/or lunotriquetral intervals; these injuries are rated as type I to type IV according to Mayfield’s classification.
The radiographs do not depict a carpometacarpal joint-hamate fracture-dislocation. A fracture-dislocation of the radial styloid would occur more proximally. The scaphocapitate and scaphotrapeziotrapezoid lie distal to the level of injury.
Which of the following scaphoid fracture patterns illustrated above has the highest incidence of avascular necrosis?
(A) A
(B) B
(C) C
(D) D
(E) E
The correct response is Option A.
Fractures of the scaphoid comprise as many as 60% of all carpal bone fractures; most of these fractures are caused by a fall onto a dorsally flexed wrist. Scaphoid fractures can be displaced or nondisplaced. In patients with nondisplaced fractures, application of a cast followed by mobilization results in a rate of union as high as 95%. A long arm thumb spica cast is typically applied first, then replaced with a short arm thumb spica cast.
In contrast, displaced fractures are often associated with an unacceptably high rate of nonunion if treated conservatively and a high incidence of avascular necrosis. This complication has been reported to occur in 13% to 40% of patients with scaphoid fractures; its incidence is dependent on the presence or absence of displacement and the anatomic location of the fracture. Because perforators to the scaphoid enter distally and proceed proximally, fractures that occur more proximally are more likely to interrupt the blood supply to the scaphoid.
The distal pole of the scaphoid has a good, protective blood supply; as a result, the risk for avascular necrosis is low. In contrast, fractures of the scaphoid waist are associated with an incidence of avascular necrosis of approximately 30%, and fractures of the proximal pole of the scaphoid have a rate of avascular necrosis that may be as high as 100%. Therefore, internal fixation is generally advocated for treatment of fractures of the proximal pole of the scaphoid. With rigid fixation of the bone, revascularization of the scaphoid occurs almost uniformly.
A 40-year-old man sustains the fracture shown in the radiograph, when he falls on his outstretched hand. Which of the following is the most appropriate management?
(A) Immobilization in a thumb spica cast for six weeks
(B) Immobilization in a long arm cast for six weeks
(C) Open reduction and compression screw fixation
(D) Open reduction and Kirschner wire fixation
(E) Scaphoidectomy
The correct response is Option C.
In this patient who has a displaced fracture of the scaphoid waist, the most appropriate management is open reduction and compression screw fixation. This can be accomplished using a Herbert, Herbert-Whipple, or Accutrak screw; the Herbert-Whipple and Accutrak screws are cannulated to allow for guided pin placement. Compression screw fixation allows reduction of the fracture and compression across the fracture site, decreasing the risk for nonunion and the time required for immobilization. Although some surgeons suggest that adequate screw fixation allows early protected range of motion and eliminates the need for cast application, most physicians still recommend postoperative cast immobilization for three to six weeks. This shortened period of immobilization decreases the potential for muscle atrophy and joint stiffness and allows the patient to return to work sooner.
Previously recommended techniques for management of displaced fractures of the scaphoid waist, including prolonged immobilization in a long arm cast for three months or longer, have been associated with nonunion or malunion rates ranging from 30% to 40%.
Kirschner wire fixation is considered an acceptable fixation method, but is associated with higher rates of nonunion than compression screw fixation. In addition, Kirschner wires are typically buried for an extended fixation time to allow bony union and require an additional operative procedure for removal.
Scaphoidectomy is appropriate for management of patients with malunion or nonunion who develop scaphoid nonunion advanced collapse (SNAC wrist), which is a progressive, patterned arthritis of the wrist that may develop in a patient with nonunion. This procedure can be performed adjuvantly with proximal row carpectomy or four-corner arthrodesis, depending on the pattern of arthritis seen in the patient. It is not appropriate in patients with acute injuries.
A 15-year-old boy sustains the fracture shown in the radiograph above when he falls on his outstretched hand during a football game. The most appropriate management is immobilization in a thumb spica cast for how many weeks?
(A) 2 to 4
(B) 5 to 6
(C) 7 to 8
(D) 10 to 14
(E) 16 to 20
The correct response is Option D.
In this patient who has a nondisplaced transverse fracture of the scaphoid waist, the wrist should be immobilized in a thumb spica cast for 10 to 14 weeks. Most surgeons agree that acute nondisplaced scaphoid fractures will generally heal if the wrist is immobilized adequately for two to three months. Some surgeons recommend immobilization in a long arm cast for the first several weeks and replacement with a short arm cast for the duration of the healing period.
Open reduction and internal fixation are indicated in patients who have scaphoid fractures with displacement of more than 1 mm because the blood supply to the bone is likely to be disrupted. Because this blood supply enters the scaphoid distally and proceeds proximally, fractures of the tubercle and distal third of the scaphoid exhibit a more rapid
healing process. Therefore, casting for no more than four to six weeks is recommended in patients with fractures of the distal third of the scaphoid if there is no displacement. In contrast, the proximal pole of the scaphoid receives the poorest blood supply, and nondisplaced fractures of the proximal pole of the scaphoid would typically be immobilized for four to six months to allow for bony union. Instead, open reduction and internal fixation can be performed even if the fracture is nondisplaced. Electrical stimulation or ultrasound can be used adjunctively to treat delayed bony union.
Because fracture healing is variable, frequent follow-up examination and radiographs are indicated. CT scans show fracture callus and bridging trabeculae in healing scaphoid fractures.
The above radiograph is from a 58-year-old mechanic who has had progressively worsening pain in the dominant right wrist for the past eight months. He reports dull pain and mild swelling over the dorsal and volar midportion of the wrist that progressively worsens during the work day. On physical examination, there is mild tenderness over the capitate and lunate.
These findings are most consistent with
(A) pantrapezial arthritis
(B) radiocarpal arthritis
(C) scapholunate advanced collapse (SLAC) wrist
(D) scaphotrapeziotrapezoidal arthritis
(E) triangular fibrocartilage complex tear
This patient has findings consistent with scapholunate advanced collapse (SLAC wrist), a common pattern of degenerative arthritis of the wrist. This patient’s condition developed following an undiagnosed scapholunate injury; other common causes include rotary subluxation or nonunion of the scaphoid, Preiser’s disease, and Kienbšck’s disease. The radiograph shows a 2.5-mm diastasis of the scapholunate joint, as well as proximal migration of the capitate between the scaphoid and lunate and loss of capitolunate joint space. The capitate will ultimately become wedged between the scaphoid and lunate.
Pantrapezial arthritis is an advanced type of basal joint arthritis of the thumb that involves the carpometacarpal and scaphotrapeziotrapezoid joints. A grind test will be positive. In radiocarpal arthritis, loss of joint space between the scaphoid and its fossa will be visible on radiographs, and the patient will have pain in the region of the anatomic snuff box. In contrast, patients with scaphotrapeziotrapezoidal (STT) arthritis will have loss of the STT joint space and positive findings on grind testing. Ulnar-sided wrist pain is typically the initial symptom of a tear of the triangular fibrocartilage complex; arthrography or arthroscopy should be used to confirm the diagnosis.
