Anatomy, NOF, Ankle, DRadius, Septic Arthritis, Open # Flashcards
All of the following implants offer adequate fracture fixation of reverse obliquity proximal femoral fracture EXCEPT:
Trochanteric entry point cephalomedullary nail
Piriformis fossa entry point cephalomedullary nail
Dynamic hip screw
Fixed angle blade plate
95 degree dynamic condylar screw
Currently, cephalomedullary nails are used widely for reverse obliquity fractures because they limit medialization of the shaft fragment unlike sliding hip screws. Reverse obliquity - 56% failure when treated with sliding hip screw
The Haidukewych et al study quoted demonstrated the superiority of fixed angle devices such as blade-plates or dynamic condylar screws over the sliding (or dynamic) hip screws. Reverse obliquity intertrochanteric fractures of the femur are recognized as biomechanically different from standard intertrochanteric fractures. The rate of failure of internal fixation for this fracture pattern was higher than the rates in most reports of internal fixation of intertrochanteric fractures devices.
Extracapsular fractures of the proximal femur between the greater and lesser trochanters
Epidemiology
incidence : roughly the same as femoral neck fractures
demographics.
female:male ratio between 2:1 and 8:1
typically older age than patients with femoral neck fractures
risk factors
proximal humerus fractures increase risk of hip fracture for 1 year
Pathophysiology
elderly : low energy falls in osteoporotic patients
young : high energy trauma
Prognosis
nonunion and malunion rates are low
20-30% mortality risk in the first year following fracture
factors that increase mortality
male gender (25-30% mortality) vs female (20% mortality)
higher in intertrochanteric fracture (vs femoral neck fracture), operative delay of >2 days , age >85 years, 2 or more pre-existing medical conditions, ASA classification (ASA III and IV increases mortality)
Surgery within 48 hours decreases 1 year mortality
early medical optimization and co-management with medical hospitalists or geriatricians can improve outcomes
Anatomy
Osteology
Intertrochanteric area exists between greater and lesser trochanters made of dense trabecular bone
Calcar femorale: vertical wall of dense bone that extends from posteromedial aspect of femoral shaft to posterior portion of femoral neck - helps determine stable versus unstable fracture patterns
Classification
Stability of fracture pattern is arguably the most reliable method of classification
Stable : intact posteromedial cortex
clinical significance - will resist medial compressive loads once reduced
Unstable : comminution of the posteromedial cortex
thinner lateral wall thickness - measured from 3 cm distal from innominate tubercle at 135 degrees to the fracture site . <20.5 mm suggests risk of postoperative lateral wall fracture
Should be treated with intramedullary implant rather than sliding hip screw
Clinical significance : fracture will collapse into varus and retroversion when loaded
Examples
fractures with a large posteromedial fragment
i.e., lesser trochanter is displaced, subtrochanteric extension, reverse obliquity , oblique fracture line extending from medial cortex both laterally and distally
Presentation: painful, shortened, externally rotated lower extremity
Imaging
Radiographs : AP pelvis, AP of hip, cross table lateral
full length femur radiographs
CT or MRI
useful if radiographs are negative but physical exam consistent with fracture
MRI useful to evaluate intertrochanteric extension with isolated greater trochanteric fracture patterns
Treatment
Nonoperative
nonweightbearing with early out of bed to chair - nonambulatory patients & patients at high risk for perioperative mortality - high rates of pneumonia, urinary tract infections, decubiti, and DVT
Operative
Sliding hip compression screw
indications : stable intertrochanteric fractures
outcomes : equal outcomes when compared to intramedullary hip screws for stable fracture patterns
technique : must obtain correct neck-shaft relationship
lag screw with tip-apex distance >25 mm is associated with increased failure rates
4 hole plates show no benefit clinically or biomechanically over 2 hole plates
pros: allows dynamic interfragmentary compression, low cost, no violation of hip abductors
cons: open technique, increased blood loss, not advisable in unstable fracture patterns (may result in
collapse, limb shortening, medialization of shaft),
can cause anterior spike malreduction in left-sided (unstable fractures due to screw torque)
Intramedullary hip screw (cephalomedullary nail)
indications : stable fracture patterns, unstable fracture patterns, reverse obliquity fractures (56% failure when treated with sliding hip screw), subtrochanteric extension, lack of integrity of femoral wall
associated with increased displacement and collapse when treated with sliding hip screw & increased risk of lateral wall fracture with decreasing lateral wall thickness
outcomes : equivalent outcomes to sliding hip screw for stable fracture patterns
technique
short implants with optional distal locking : standard obliquity fractures
long implants : standard obliquity fractures, reverse obliquity fractures, subtrochanteric extension
pros : percutaneous approach, minimal blood loss, may be used in unstable fracture patterns
cons : periprosthetic fracture, higher cost than sliding hip screw , requires violation of hip abductors for insertion
Arthroplasty
indications: severely comminuted fractures, preexisting symptomatic degenerative arthritis, osteoporotic bone that is unlikely to hold internal fixation, salvage for failed internal fixation
technique : calcar-replacing prosthesis often needed
must attempt fixation of greater trochanter to shaft
pros : possible earlier return for full weight bearing
cons : increased blood loss, may require prosthesis that some surgeons are unfamiliar with
Complications
Implant failure and cutout - most common complication
usually occurs within first 3 months
cause : tip-apex distance >45 mm associated with 60% failure rate
treatment
young: corrective osteotomy and/or revision open reduction and internal fixation
elderly : total hip arthroplasty
Anterior perforation of the distal femur
incidence
can occur following intramedullary screw fixation
cause : mismatch of the radius of curvature of the femur (shorter) and implant (longer)
posterior starting point on the greater trochanter
Nonunion
incidence <2%
treatment : revision ORIF with bone grafting, proximal femoral replacement
Malunion
varus and rotational deformities are common
treatment : corrective osteotomies
Poor pre-injury cognitive function has been proven to increase mortality for which of the following injuries?
Proximal humerus fracture Distal radius fracture Pelvic ring fracture Hip fracture Distal femur fracture
Several studies have shown that only patient age and pre-injury functional independence measure scores were independent predictors of functional outcome after hip fracture.
Hip fractures are common injuries and typically sustained from a standing level fall in the elderly. These fragility fractures can be a clinical sign of overall decline of the patient, and when coupled with poor pre-injury cognitive function and decreased mobility, mortality rates are increased as compared to patients of the same age.
The Soderqvist et al study showed that a Short Portable Mental Status Questionnaire score of <3 and male gender were associated with an increased mortality rate during the first twelve months. Moreover, patients with a score of <3 had a significantly worse outcome with regard to the ability to walk and to perform the activities of daily living.
The referenced study by Holt et al is a prospective review of 1000 hip fractures and reported that pre-injury mobility to be the most significant determinant for post-operative survival.
The referenced study by Cornwall et al found that six-month mortality was lowest for patients with nondisplaced femoral neck fractures (5.7%) and highest for patients with displaced femoral neck fractures (15.8%), but multivariate analysis only identified preinjury function as an independent predictor of mortality.
Illustration A shows a displaced femoral neck fracture in an elderly patient.
Incorrect Answers:
1,2,3,5: These injuries can be associated with elderly patients and are common fragility fractures. However, no relationship between mortality and pre-injury cognitive function has been established at this point with any of these fractures.
A 25-year-old male sustains an ankle fracture dislocation and undergoes open reduction and internal fixation. He returns to clinic five months following surgery complaining of continued ankle pain and instability with weight bearing. His immediate post-operative AP radiograph is shows a syndesmotic screw, 2 medial malleolus screws, unreduced mid shaft fibula fracture. Which of the following could have prevented this patient from developing persistent pain?
Deep deltoid ligament repair
Quadricortical syndesmotic screw fixation
Restoration of fibular length and rotation
Lateral collateral ligament complex repair
Use of two syndesmotic screws
The patient presents with continued ankle pain and instability following open reduction and internal fixation. The radiograph in figure A demonstrates inadequate restoration of fibular length, likely leading to continued tibiotalar instability.
Illustration A demonstrates fibular malreduction with dislocation of the fibula anterior to the tibial incisura. Illustration B shows a comminuted fibula fracture along with a measurement of length from an intact fibula. The arc from the lateral process of the talus to the peroneal groove of the distal fibula is known as the “dime” sign and should remain unbroken if fibular length has been restored. Illustration C demonstrates the use of a push-pull screw and lamina spreader to regain length intraoperatively for a comminuted fibula fracture.
Chu and Weiner review management of malunions of the distal fibula. The authors state that restoration of fibular length, alignment and rotation leads to reduction of the talus, provides a buttress to talar motion in the setting of an incompetent deltoid, and allows the syndesmotic ligaments to heal at the appropriate tension.
Wikeroy et al conducted a study of patients from a prior prospective, randomized control trial comparing different methods of syndesmotic fixation. There was no significant difference in outcomes between tricortical or quadricortical 3.5mm screw fixation, however worse outcomes were seen with associated posterior malleolar fractures, obesity, a difference in sydesmotic width of 1.5mm or greater, and a CT confirmed tibio-fibular synostosis.
Sinha et al present a simple technique for fibular lengthening in the setting of distal fibula malunion. They found high union rates and improved AOFAS scores at short-term follow up with their technique.
Which muscles cause the fracture displacement of the proximal fragment shown in proximal femoral fractures - proximal fragment abducted, ?
gluteus maximus and adductors gluteus maximus and rectus femoris gluteus medius and hamstrings gluteus medius and iliopsoas rectus femoris and hamstrings
The gluteus medius attaches to the greater trochanter, leading to abduction, while the iliopsoas attaches to the lesser trochanter, leading to flexion. French et al evaluated forty-five Russell-Taylor Type 1B subtrochanteric femoral fractures which were stabilized using an interlocked cephalomedullary nail. The intraoperative complication rate was 13.5%; and the most frequent complication was a varus malreduction. The primary reason for this was failure to counteract the muscle forces acting on the proximal fragment combined with the adducted position of the distal femur during portal creation. This problem can be avoided if the position of the proximal fragment is evaluated carefully and reduced before guidewire insertion.
Which of the following is a recognized predictor of mortality after hip fracture?
American Society of Anesthesiologist (ASA) classification Post-operative weight bearing status Fracture Comminution Fixation device used Type of anesthetic used
American Society of Anesthesiologist (ASA) classification is predictive of post-surgical mortality in hip fracture patients.
The ASA classification (detailed in Illustration A) was initially developed in 1963 and has been shown to be predictive of post-surgical mortality in hip fracture patients. Basic categories are as follows: 1= normal, healthy; 2= mild systemic disease; 3= severe systemic disease, not incapacitating; 4= severe incapacitating systemic condition, constant threat to life; 5= moribund patient; 6 = brain dead, organs being donated.
Richmond et al. looked at 836 patients treated for a hip fracture and found that this injury is not associated with significant excess mortality among patients older than age 85. However, in younger patients, those with ASA classifications of 3 or 4 have significant excess mortality following hip fracture that persists up to 2 years after injury.
Holt et al. investigated the relationship between a number of patient and management variables and mortality after surgery for fracture of the hip. Data relating to 18,817 patients were obtained from the Scottish Hip Fracture Audit database. They found that type of anesthetic did not adversely affect the 30 or 120 day mortality rate.
A 36-year-old male sustains an open segmental tibia fracture associated with an overlying 8 cm soft tissue avulsion that requires skin grafting for soft tissue coverage. No vascular injury is identified. What is the most appropriate Gustilo-Anderson classification of this injury?
Type I Type II Type IIIA Type IIIB Type IIIC
An 8cm open segmental tibia fracture requiring skin grafting (but not a skin flap) qualifies as a Gustilo Type IIIA.
An open segmental tibia fracture meets criteria to be a type III injury, and subclassification as a IIIA is due to the lack of a need for free or regional tissue transfer for coverage. Classification as a type IIIB would require a free or regional soft tissue transfer (flap) for coverage. Also, remember that definitive classification is done intraoperatively, after full assessment of the fracture and wound are complete.
Gustilo et al. performed a retrospective review of 673 patients and a prospective review of 352 patients with open fractures. Infection rate of the type I and II in the retrospective series was 12%, and this decreased with use of a standardized modern treatment protocol to 2.5% in the prospective cohort. Type III deep infection rate was 44% in the retrospective study and 9% in the prospective study.
Incorrect Answers:
Answer 1: Involves a wound <1 cm with minimal soft tissue stripping; simple fracture pattern
Answer 2: Involves a wound 1-10cm with mild soft tissue stripping; simple fracture pattern or mild comminution
Answer 4: Involves extensive soft tissue damage with high-energy fracture pattern; soft tissue requires free tissue transfer for coverage
Answer 5: Involves a vascular injury requiring repair
A 50-year-old laborer presents with clumsiness of his hand. . On physical exam he is found to positive Froment sign, decreased cutaneous sensation over the ulnar border of his small finger and has a positive Tinel’s sign at the medial elbow. While undergoing elective surgery for this condition, the affected nerve is transected while attempting to excise the medial intermusular septum. Postoperatively, what limitation to his elbow function would you expect?
Decreased flexion Decreased extension No limitation Decreased supination Decreased pronation
This patient has clinical findings consistent with cubital tunnel syndrome. Laceration of the nerve above the level of the elbow will not affect his elbow function.
The ulnar nerve originates from the medial cord of the brachial plexus. It pierces the medial intermuscular septum as it courses from anteromedial to posteromedial in the upper half of the arm. As the nerve traverses distal to the cubital tunnel, it will give rise to motor branches that feed the FCU and the FDP to the small and ring fingers. The function of the elbow is predicated on the the motor innervations of the radial nerve, musculocutaneous and median nerves. While the ulnar nerve innervates some of the ulnar based flexors of the forearm, elbow function is not affected when it is transected.
Mazurek et al. review the anatomy of the median, radial and ulnar nerves, along with the clinical implications of compression neuropathies of each. Although the ulnar nerve has a significant course in the upper arm as it passes from the anterior to the posterior compartment, the first branches of the ulnar nerve are sensory branches to the elbow joint capsule. The remainder of the ulnar nerve branches are in the forearm and the hand. No distinct contribution to elbow function is noted.
Figure A demonstrates a patient with cubital tunnel syndrome; because the FDP to the small and ringer finger is affected as well, the degree of clawing is not as severe as in a patient with ulnar nerve compression at Guyon’s canal. There is atrophy of the 1st dorsal webspace consistent with the condition.
Incorrect Answers
Answer: 1, 2, 4, 5: Given the course of the ulnar nerve in the upper arm, an injury to the nerve above the elbow will not compromise elbow function.
The inferior and superior gluteal nerves are designated as such based on their relationship to what structure?
The gluteus maximus The gluteus minimus The piriformis muscle The sciatic nerve The sacrospinous ligament
The piriformis muscle
The superior gluteal nerve arises from the posterior roots of L4, L5, and S1 in the lumbosacral plexus. It exits the pelvis through the superior part of the greater sciatic notch, just superior to the piriformis tendon. It courses between the gluteus medius and minimus, supplying both muscles, as well as the tensor fascia lata. The inferior gluteal nerve arises from the posterior roots of L5, S1, and S2 in the lumbosacral plexus and exits the pelvis through the greater sciatic notch, under the piriformis. It courses on the deep surface of gluteus maximus and provides the sole motor innervation for this muscle.
Illustration A demonstrates the anatomic relationship between the superior and inferior gluteal nerves to the piriformis
Increasing the oxygen gradient for diffusion is the mechanism of action for which of the following methods of treatment of lower extremity trauma?
Open fasciotomy Percutaneous fasciotomy High-dose anti-inflammatories Hyperbaric oxygen therapy Negative pressure wound therapy
Hyperbaric oxygen therapy (HBO) allows patients to breathe 100% oxygen in a chamber under conditions of increased barometric pressure.
This tremendous partial pressure of oxygen supports gas diffusion for a much greater distance than under normal conditions, thus delivering oxygen to relatively ischemic and hypoxic tissues. Trauma-related indications for HBO therapy include carbon monoxide intoxication, gas gangrene, crush injury, compartment syndrome, necrotizing fasciitis, treatment of chronic osteomyelitis, support of grafts and flaps, and burns. Contraindications relate to issues of gas exchange, oxygen sensitivity, and technical safety.
The cited reference is a useful review article of hyperbaric oxygen therapy in extremity trauma.
A 76-year-old female with underlying osteoporosis presents with severe right leg pain after stepping off a curb. Current femur radiographs are shown in Figure A. Review of the patient’s medical records reveal that she had been evaluated 3 months prior for right hip pain, and work-up at that time was negative. Radiographs of the patient’s femur from that previous visit are shown in Figure B. What is the most likely cause of this patient’s femur fracture?
Figure A shows a transverse subtrochanteric femur fracture. Figure B shows diaphyseal cortical thickening and cortical beaking at the subtrochanteric area.
Fibrous cortical defect Metastatic lesion Acute trauma Bisphosphonate treatment Osteomyelitis
The patient’s injury is most consistent with a bisphosphonate induced atypical femur fracture.
Atypical subtrochanteric femoral fractures have been identified as a potential complication of long-term bisphosphonate therapy for the treatment of osteoporosis. Prodromal symptoms of thigh pain are common prior to fracture, and bony failure is usually associated with low energy mechanisms.
Puhaindran et al. performed a retrospective review of the imaging studies and case notes for patients with skeletal malignant involvement who received a minimum of twenty-four doses of intravenous bisphosphonates. Patients were classified as having an atypical subtrochanteric femoral fracture if they had a transverse subtrochanteric fracture following low-energy trauma or an impending fracture, together with radiographic findings. In the study cohort of 327 patients, four patients developed an atypical subtrochanteric femoral fracture. All four patients were female, three had breast cancer, and one had myeloma.
Feldman et al. reviewed the imaging presentations on routine radiographs, alternate imaging modalities, and associated pitfalls in nine atypical femur fractures in six patients. The author states that effects may differ with each bisphosphonate’s route of administration and prolongation of activity, despite discontinuation. The review also discusses the theoretical mechanisms of bisphosphonates as a class rather than with a specific alendronate association and provides a broader basis for evaluating the recently observed clinical and radiographic complications.
Figure A shows a transverse subtrochanteric femur fracture. Figure B shows diaphyseal cortical thickening and cortical beaking at the subtrochanteric area.
Incorrect Answers:
Answer 1: The radiographic findings are not consistent with a fibrous cortical defect.
Answer 2: The radiographic findings are not consistent with the presence of a metastatic lesion.
Answer 3: Subtrochanteric fractures are typically associated with high energy trauma, and this patients mechanism of injury is atypical.
Answer 5: There is no radiographic or clinical evidence supporting the presence of chronic osteomyelits.
A 54-year-old male falls from a ladder and sustains a distal radius fracture. Which of the following factors has been associated with redisplacement of the fracture after closed manipulation?
Triangular fibrocartilage complex tear Open injury Ipsilateral radial head fracture Time to reduction Severity of initial displacement
Several factors have been associated with re-displacement following closed manipulation of a distal radius fracture: the initial displacement of the fracture (the greater the degree of displacement, particularly radial shortening), the age of the patient (older patients with osteopenic bones displace late), and the extent of metaphyseal comminution.
Acceptable radiographic parameters for a healed radius in an active, healthy patient <65 years old include: radial length within 5mm of the contralateral wrist, dorsal tilt <10 degrees, intraarticular step-off of less than 2 mm, and less than 5 degree loss of radial inclination.
Figure A shows a lateral view of a distal radius fracture.
Ilyas and Jupiter review the classification, treatment, and operative indications for distal radius fractures in the referenced review article.
Anterior perforation of the distal femur from antegrade femoral nailing has been attributed to what factor?
Non-anatomic reduction Mismatch of the radius of curvature of implant and bone Usage of too large an implant Lateral patient positioning Lateral proximal starting point
Anterior perforation of the femur has been attributed to a simple mismatch in the radius of curvature of implants and the apex anterior bowed femur.
The radius of curvature is generally smaller (114-120 cm) than many earlier generation femoral nails (up to 300 cm), and the referenced article by Ostrum et al describes a case series of 3 such patients with subtrochanteric fractures. He noted that the difference in femoral anteroposterior bow between the bone and the implant is a contributing factor to distal femoral anterior cortex penetration in intramedullary nailing of subtrochanteric fractures.
A 45-year-old male with long-standing diabetes sustains a bimalleolar ankle fracture. He has a BMI of 38, established peripheral neuropathy, and his most recent HbA1c is 8.8. What is the most appropriate definitive management option?
Aircast boot Close contact cast Fibular plate and MM screw (Standard Tx) Augmented standard Tx (extra syndesmotic fixation, longer fibular plate) Ex-fix
Open reduction and internal fixation (ORIF) remains the mainstay of treatment for ankle fractures in patients with diabetes.
ORIF for ankle fractures in diabetics can be augmented with increased density of fixation to account for notable, pathologic bone. Specifically, multiple quadricortical syndesmotic screws, bicortical medial malleolar screws, and stiffer plates are all viable options. Furthermore, due to delayed healing properties, prolonged immobilization may also be required to avoid fixation failure.
Guo et al. performed a cohort controlled comparison between diabetics and non-diabetic patients with operative ankle fractures. Although they hypothesized that there would be more complications in the diabetic group, there was no statistical differences in fixation failure or complications when adhering to treatment principles for diabetics (including prolonged non-weight bearing for 10-12 weeks and increased density of fixation).
Chaudhary et al. review the notable complications following ankle fracture treatment in patients with diabetes. In reviewing the literature, the authors recommend ORIF with meticulous soft tissue handling, increased density of fixation, and prolonged immobilization as the mainstay of diabetic ankle fracture treatment. External fixation and frames, while treatment options, should be reserved for salvage or infectious clinical scenarios.
Incorrect Answers:
Answers 1,2: Non-operative treatment is not appropriate for this fracture pattern
Answer 3: Figure D, typically used for those without diabetes is less appropriate for this patient/clinical scenario.
Answer 5: While external fixation and a ring fixator may be utilized, ORIF should be attempted first, however, as it provides stiffer fixation.
A 72-year-old male sustains the injury shown standard obliquity proximal femoral fracture as a result of a fall from a ladder. Which of the following factors has been shown to be associated with increased collapse or sliding displacement?
Use of a long intramedullary device Use of a short intramedullary device Use of external fixation Postoperative weight bearing status Intraoperative fracture of the lateral femoral wall
Intertrochanteric hip fractures with lateral wall fractures should be treated with an intramedullary device as opposed to a sliding hip screw, as the intact lateral wall provides a buttress for the proximal fragment facilitating fracture impaction as well as rotational and varus stability.
Palm et al showed that 22% of patients with a fractured lateral femoral wall underwent reoperation for collapse of fracture compared to 3% with an intact lateral femoral wall. Interestingly, 74% of the lateral proximal femoral wall fractures were iatrogenic during the procedure itself.
Gotfried et al reported on 24 patients with postoperative intertrochanteric hip fracture collapse and noted that this complication followed fracture of the lateral wall in every instance and resulted in a protracted period of disability until fracture healing. They recommend care when drilling at the base of the lateral wall intraoperatively.
Lindskog et al review the diagnosis, treatment, as well as biomechanical reviews of treatment options for unstable intertrochanteric hip fractures.
Incorrect Answers:
Answer 1, 2, and 3: No difference in collapse has been shown between long or short intramedullary devices and an external fixator in stable intertrochanteric hip fractures.
Answer 4: Early postoperative weightbearing is the goal after repair, and no differences have been shown in collapse rates with different weight bearing protocols
Which of the following unipennate muscles takes its origin on the radial side of the profundus tendon, inserts on the radial lateral band at the middle phalanx, and creates a force vector that is palmar to the joint axis of the metacarpophalangeal joint?
1st lumbrical 1st dorsal interosseous 4th dorsal interosseous 4th lumbrical 4th palmar interosseous
The 1st and 2nd lumbricals are unipennate and originate on the flexor digitorum profundus (FDP) to these fingers. The 3rd and 4th lumbricals are bipennate and each have one head that originates from the FDP from the respective finger and a second head that originates from the FDP of the middle and ring finger, respectively (Illustration A).
Lumbrical insertion is classically thought to be on the radial lateral band of the extensor expansion, but Eladoumikdachi et al performed a cadaveric dissection on 14 hands and found that the insertions were variable and included proximal phalanx and volar plate. The lumbricals extend the PIP and DIP joints while also flexing the MCP joint.
Their mechanism is pathologically exemplified in the intrinsic-plus hand with associated intrinsic tightness, where the contracted intrinsic muscles (lumbricals and interosseous) as shown in (Illustration B) will prevent supple DIP/PIP flexion. The 1st and 4th dorsal interosseous muscles are bipennate muscles originating from the adjacent metacarpals of each web space and causes abduction of the fingers. The 3 palmar interosseous muscles are located on the ulnar side of the index metacarpal and on the radial aspect of the ring and small metacarpals. They insert on to the lateral bands of their respective digits and cause adduction of the fingers.
