ABOS Part I & AAOS OITE Orthopedic Surgery Review: Pilon & Humeral Fractures | Part 21582

This module offers a comprehensive review of Pilon and Humeral fractures for ABOS Part I and AAOS OITE exams. It features 20 advanced multiple-choice questions derived from high-yield clinical cases, covering Gusillo–Anderson classification, surgical management, complications like nonunion and infection, and post-operative rehabilitation strategies for these critical orthopedic injuries.

ABOS Part I & AAOS OITE: Pilon & Humeral Fractures

Question 1

A 38-year-old male presents to the emergency department after a high-energy motor vehicle collision, sustaining a severe injury to his right ankle. Initial radiographs show a comminuted intra-articular fracture of the distal tibia with significant displacement and impaction of the plafond. The fibula is also fractured. Clinically, there is marked swelling, tense skin, and multiple large blisters over the anteromedial aspect of the ankle. There is no open wound. A CT scan confirms extensive articular fragmentation involving multiple irreducible fragments and substantial subchondral bone loss, along with severe metaphyseal comminution and segmental defects. Based on the Gusillo–Anderson (G-A) Classification System, what is the most appropriate classification for this injury?

Explanation

Correct Answer: C

The patient's presentation aligns with a G-A Type C, Subtype 3, Grade S3 classification. Let's break down the components:

Articular Involvement (G-A Type): The description of 'extensive articular fragmentation involving multiple irreducible fragments and substantial subchondral bone loss' directly corresponds to Type C, which signifies severe articular comminution.
Metaphyseal Comminution (G-A Subtype): 'Severe metaphyseal comminution and segmental defects' matches Subtype 3, characterized by extensive bone loss and challenging anatomical reduction.
Soft Tissue Envelope (G-A Grade): 'Marked swelling, tense skin, and multiple large blisters' indicates a severe soft tissue injury. While not an open fracture, the presence of significant edema and blistering, especially with tense skin, points towards Grade S3, which includes severe crush injury or impending skin necrosis, necessitating a prolonged staged approach. Grade S2 typically involves significant edema and blistering but might not have the 'tense skin' or 'impending necrosis' implication of S3. Given the high-energy mechanism and severe osseous injury, the soft tissue compromise is likely severe enough to warrant S3.

Therefore, the most appropriate classification is Type C, Subtype 3, Grade S3.

Question 2

A 55-year-old construction worker sustains a G-A Type B, Subtype 2, Grade S2 pilon fracture after falling from a height. He presents with significant ankle swelling and tense skin, but no open wounds. Initial management involves closed reduction and application of a spanning external fixator. Two weeks later, the swelling has significantly decreased, and the 'wrinkle sign' is positive. The patient is medically optimized. What is the most appropriate next step in management?

Explanation

Correct Answer: B

The case describes a G-A Grade S2 injury, which mandates a staged approach with initial external fixation. The key indicator for proceeding to definitive open reduction internal fixation (ORIF) is the resolution of soft tissue edema, clinically assessed by the 'wrinkle sign.' The case explicitly states that the 'wrinkle sign' is positive and the patient is medically optimized, indicating that the soft tissue envelope has recovered sufficiently for definitive surgery. The literature consistently supports this staged approach to minimize wound complications.

A. Initiate immediate full weight-bearing in a CAM walker: This is incorrect. The fracture is a G-A Type B, Subtype 2, requiring anatomical reduction and stable fixation. Immediate full weight-bearing without definitive fixation would lead to collapse and malunion.
C. Continue external fixation for another 4 weeks to ensure complete soft tissue healing: This is incorrect. While soft tissue healing is paramount, the 'wrinkle sign' indicates readiness for definitive fixation. Prolonged external fixation beyond this point unnecessarily delays anatomical reduction and increases the risk of pin tract infection and joint stiffness.
D. Perform an ankle arthrodesis due to the severity of the injury: This is incorrect. Ankle arthrodesis is a salvage procedure for severe post-traumatic arthritis or failed reconstruction, not a primary treatment for an acute pilon fracture, especially when anatomical reduction is achievable.
E. Discharge the patient with a cast and instruct on non-weight-bearing: This is incorrect. A G-A Type B, Subtype 2 fracture is a displaced intra-articular injury requiring operative management to restore articular congruity and prevent post-traumatic arthritis. Non-operative management is reserved for non-displaced, stable Type A fractures.

Question 3

A 42-year-old male presents with a G-A Type C, Subtype 3, Grade S2 pilon fracture following a fall from a ladder. After initial external fixation, a definitive surgical plan is being formulated. Which of the following imaging modalities is considered mandatory and most crucial for detailed pre-operative planning, especially for the articular component of this fracture?

Explanation

Correct Answer: C

The case explicitly states that for all G-A Type B and C fractures, a Computed Tomography (CT) scan is mandatory. Fine-cut (1-2mm) CT scans with 3D reconstructions are indispensable for defining articular comminution, fragment size, location, and depression. This allows for precise surgical planning, including approach selection, identification of key fragments for reduction, and assessment of bone loss. Given the G-A Type C classification, which denotes severe articular comminution, the CT scan is the most crucial imaging modality.

A. Plain radiographs (AP, lateral, mortise views): While essential initial assessments, plain radiographs provide limited information regarding the extent of articular comminution, impaction, and fragment orientation in complex intra-articular fractures like pilon fractures.
B. Magnetic Resonance Imaging (MRI): Rarely indicated unless there is suspicion of significant ligamentous injury beyond the syndesmosis, or for assessing occult soft tissue lesions (e.g., tendon rupture). It is not the primary modality for detailed osseous fracture planning.
D. Bone scintigraphy: This is a nuclear medicine study used to detect bone pathology, such as stress fractures, infections, or tumors. It has no role in acute fracture planning for pilon fractures.
E. Arteriogram: An arteriogram is used to visualize blood vessels and is indicated if there is suspicion of vascular injury, typically in cases of severe open fractures or signs of ischemia. It is not a routine pre-operative planning tool for the fracture morphology itself.

Question 4

A surgeon is planning definitive ORIF for a G-A Type B, Subtype 2 pilon fracture with significant anterolateral articular involvement. The chosen approach is the anterolateral approach. Which of the following describes the correct internervous plane and key neurovascular structures to protect during this approach?

Explanation

Correct Answer: B

The case details the surgical anatomy and approaches. For the anterolateral approach:

Internervous Plane: It utilizes the interval between the tibialis anterior muscle (innervated by the deep peroneal nerve) and the extensor digitorum longus muscle (also deep peroneal nerve). While technically not a true internervous plane as both muscles are supplied by the deep peroneal nerve, it is a functional interval.
Neurovascular Structures: Access is achieved by retracting the extensor tendons and the neurovascular bundle (anterior tibial artery and deep peroneal nerve) medially. Therefore, protecting the anterior tibial artery and deep peroneal nerve is crucial.

Let's evaluate the other options:

A. Between the flexor hallucis longus and the peroneus longus/brevis, protecting the posterior tibial artery and nerve: This describes the posterolateral approach, which accesses the posterior malleolus and posterolateral plafond, and protects the posterior neurovascular bundle.
C. Between the flexor digitorum longus and the tibialis posterior, protecting the saphenous nerve and vein: This describes the posteromedial approach, which accesses the posteromedial aspect of the tibia. The saphenous nerve and vein are typically protected in the anteromedial approach.
D. Directly over the medial malleolus, protecting the superficial peroneal nerve: This describes the anteromedial approach. The superficial peroneal nerve is anterolateral and would be at risk with an anterolateral incision, but this option incorrectly places it with the anteromedial approach.
E. Between the gastrocnemius and soleus, protecting the sural nerve: This describes a posterior approach to the tibia, typically for proximal or mid-shaft fractures, not specifically for the distal pilon, and the sural nerve is typically protected in posterolateral approaches.

Question 5

During definitive ORIF of a G-A Type C pilon fracture, the surgeon has successfully reduced and fixed the associated fibula fracture. The next critical step, as emphasized by the literature and surgical technique, is to address the articular surface. Which of the following best describes the primary goal and technique for articular reconstruction in this scenario?

Explanation

Correct Answer: C

The case and key literature emphasize that anatomical reduction of the articular surface is the primary determinant of long-term outcome, especially for G-A Type B and C fractures. For a G-A Type C fracture, which involves severe articular comminution and often substantial subchondral bone loss, direct visualization and meticulous reconstruction are paramount. This involves elevating depressed fragments and filling subchondral bone voids with autogenous or allograft bone to support the articular surface.

A. Achieve indirect reduction of the articular fragments using ligamentotaxis and bridge plating: While indirect reduction and bridge plating are valuable for metaphyseal comminution (G-A Subtype 2 & 3) to preserve vascularity, they are generally insufficient for achieving anatomical articular reduction in complex intra-articular fractures. Direct visualization is usually required for the articular surface.
B. Prioritize metaphyseal reduction and fixation, then address articular fragments if easily accessible: This is incorrect. The case explicitly states that articular reconstruction is the primary determinant of long-term outcome and should be addressed first, often after fibular fixation, to provide a stable base for metaphyseal reconstruction.
D. Perform a limited arthrotomy and stabilize the largest articular fragment with a single lag screw: While a limited arthrotomy may be used, stabilizing only the largest fragment with a single screw is unlikely to achieve anatomical reduction and stable fixation of a severely comminuted G-A Type C articular surface. Multiple fragments often need to be reduced and fixed.
E. Bypass the articular comminution entirely with an external ring fixator: While external ring fixators are an option for definitive fixation in highly comminuted open fractures or severe soft tissue injuries, the primary goal for articular fractures is still anatomical reduction. Ring fixators can achieve this, but the option implies bypassing reduction, which is not the goal.

Question 6

A 28-year-old male presents with a G-A Type B, Subtype 2, Grade S1 pilon fracture with an associated displaced fibula fracture. During definitive ORIF, after exposing the fracture, the surgeon's initial step is to address the fibula. What is the primary biomechanical reason for prioritizing the restoration of fibular length and rotation in the management of pilon fractures?

Explanation

Correct Answer: C

The case highlights the importance of fibular integrity: 'The fibula plays a critical role in maintaining the length and rotation of the distal tibia and serves as a buttress against talar displacement.' The surgical technique section further states: 'If the fibula is fractured and displaced, restore its length, rotation, and alignment first. This provides an anatomical template for tibial reconstruction.' Therefore, the primary biomechanical reason is that the fibula acts as a stable external frame and template for restoring the more complex tibial length and rotation.

A. To prevent compartment syndrome in the lateral compartment: While compartment syndrome is a risk, fixing the fibula primarily addresses stability and alignment, not directly preventing compartment syndrome, which is managed by fasciotomy.
B. The fibula is a non-weight-bearing bone, so its early fixation simplifies later steps: While the fibula bears less weight than the tibia, its role in maintaining ankle mortise stability and acting as a template is crucial, not just a simplification.
D. To facilitate the placement of syndesmotic screws later in the procedure: While fibular fixation is a prerequisite for assessing and potentially fixing the syndesmosis, its primary role is as a template for the tibia, not just to facilitate screw placement.
E. To reduce the risk of superficial peroneal nerve injury during subsequent tibial plating: While nerve protection is always important, fixing the fibula first does not directly reduce the risk of superficial peroneal nerve injury during tibial plating. This nerve is at risk during anterolateral approaches to the tibia regardless of fibular fixation timing.

Question 7

A 68-year-old female with severe osteoporosis sustains a G-A Type C, Subtype 3, Grade S2 pilon fracture. After initial external fixation and soft tissue recovery, definitive ORIF is planned. Given the severe metaphyseal comminution and osteoporosis, which surgical principle is most appropriate for managing the metaphyseal component of this fracture?

Explanation

Correct Answer: C

For G-A Subtype 3 fractures with significant metaphyseal comminution, especially in the context of osteoporosis, the case and literature emphasize the use of indirect reduction maneuvers and Minimally Invasive Plate Osteosynthesis (MIPO) techniques. These approaches aim to preserve the blood supply to comminuted fragments, minimizing soft tissue stripping. Locking plates are ideally suited for bridging comminuted zones and providing stable fixation in osteoporotic bone without requiring direct bone-plate contact.

A. Extensive soft tissue stripping to achieve direct visualization and anatomical reduction of every comminuted fragment: This is a 'mistake to avoid' as per the literature. Extensive stripping increases devascularization and the risk of nonunion and infection, particularly in G-A S3 injuries or comminuted fractures.
B. Primary use of a non-locking buttress plate with multiple lag screws for interfragmentary compression: While buttress plates are used, non-locking plates rely on compression to the bone, which is less effective in severely comminuted or osteoporotic bone. Locking plates provide angular stability independent of bone quality and are preferred for bridging comminution. Lag screws are for articular fragments, not typically for bridging comminuted metaphysis.
D. Immediate full weight-bearing post-operatively to promote bone healing: This is incorrect and highly risky. Severe comminution and osteoporosis necessitate a conservative, delayed weight-bearing protocol to allow for adequate bone healing and prevent hardware failure or collapse.
E. Exclusive use of external fixation as the definitive treatment without internal fixation: While external fixators can be definitive in some severe cases (e.g., open fractures, infection), for a G-A Type C, Subtype 3 fracture, the goal is usually to achieve internal fixation after soft tissue recovery to allow for better articular reduction and earlier functional recovery, unless internal fixation is absolutely contraindicated.

Question 8

A 35-year-old male undergoes definitive ORIF for a G-A Type C, Subtype 2, Grade S2 pilon fracture. Post-operatively, at 3 weeks, he develops increasing pain, redness, swelling, and purulent discharge from one of the surgical incisions. Radiographs show no loss of reduction. What is the most likely complication and the appropriate initial salvage strategy?

Explanation

Correct Answer: C

The patient's symptoms of increasing pain, redness, swelling, and purulent discharge from a surgical incision, 3 weeks post-operatively, are classic signs of a deep surgical site infection. The case lists deep infection as a common complication with an incidence of 5-15%, especially in G-A S2/S3 injuries. The appropriate initial salvage strategy for a deep infection is urgent surgical debridement, irrigation, obtaining cultures, and initiating IV antibiotics tailored to sensitivities. Retention of hardware may be possible if stable and reduction is maintained, but debridement is paramount.

A. Post-traumatic arthritis; initiate aggressive physical therapy: Post-traumatic arthritis is a long-term complication, typically developing months to years after the injury, not 3 weeks post-op. Aggressive physical therapy would be inappropriate in the presence of an active infection.
B. Nonunion; revise ORIF with bone grafting: Nonunion is a failure of fracture healing, which takes months to diagnose. While infection can contribute to nonunion, the immediate problem is the acute infection.
D. Hardware irritation; schedule hardware removal at 6 months: Hardware irritation typically presents as localized pain or prominence after fracture union (12-18 months), not with signs of acute infection and purulent discharge at 3 weeks.
E. Complex Regional Pain Syndrome (CRPS); start sympathetic blocks: CRPS presents with disproportionate pain, swelling, skin changes, and autonomic dysfunction, but typically without purulent discharge. While CRPS can occur, the purulent discharge points directly to infection.

Question 9

A 48-year-old female undergoes ORIF for a G-A Type B, Subtype 1, Grade S1 pilon fracture. The fixation is deemed stable intraoperatively. According to the general principles of post-operative rehabilitation, when would the surgeon most likely consider initiating gradual partial weight-bearing (PWB) for this patient?

Explanation

Correct Answer: C

The rehabilitation protocol outlines a phased approach. Phase 1 (Weeks 0-6) is strictly Non-Weight-Bearing (NWB). Phase 2 (Weeks 6-12) involves 'Progressive Weight-Bearing & Strengthening.' The case states: 'The transition to PWB is guided by clinical and radiographic evidence of healing (callus formation, absence of hardware loosening). For G-A Type C/Subtype 3 fractures, this may be delayed until 8-10 weeks or longer.' For a G-A Type B, Subtype 1 fracture with stable fixation, initiating gradual PWB typically falls within the 6-12 week window, once initial healing is evident.

A. Immediately post-operatively (Week 0-1): This is incorrect. The initial phase (Weeks 0-6) is strictly NWB to protect the surgical repair.
B. At 2-3 weeks post-operatively, once sutures are removed: This is incorrect. While early gentle range of motion may begin, weight-bearing is still NWB during this period.
D. Only after 6 months, once full union is confirmed radiographically: This is too conservative for a G-A Type B, Subtype 1 fracture with stable fixation. While full union takes longer, progressive weight-bearing starts much earlier.
E. Never, as pilon fractures always require strict non-weight-bearing indefinitely: This is incorrect. The goal of surgery and rehabilitation is to restore weight-bearing capacity.

Question 10

A 50-year-old male, 2 years after sustaining a G-A Type C, Subtype 3 pilon fracture and undergoing ORIF, presents with persistent, debilitating ankle pain, stiffness, and radiographic evidence of severe post-traumatic osteoarthritis. He has failed conservative management including NSAIDs and injections. What is the most appropriate long-term salvage option for this patient?

Explanation

Correct Answer: B

The case's 'Complications & Management' and 'Summary of Key Literature' sections discuss post-traumatic arthritis as a common long-term complication, especially for G-A Type C fractures. When conservative management fails for severe pain and deformity due to post-traumatic arthritis, the advanced options are ankle arthrodesis (fusion) or total ankle arthroplasty (joint replacement). The choice between these depends on patient factors, deformity, and remaining bone stock.

A. Repeat ORIF with revision plating: This is incorrect. Revision ORIF is for nonunion or malunion, not for established severe post-traumatic arthritis where the joint surface is already destroyed.
C. Aggressive physical therapy and manipulation under anesthesia: While physical therapy is part of initial management for stiffness, it is unlikely to resolve debilitating pain from severe, established post-traumatic osteoarthritis. Manipulation under anesthesia is for stiffness, not joint destruction.
D. Hardware removal alone: Hardware removal is indicated for symptomatic hardware irritation after fracture union, but it will not address the underlying severe post-traumatic arthritis and joint destruction.
E. Long-term opioid therapy for pain management: While pain management is necessary, long-term opioid therapy is generally not considered a definitive 'salvage option' for a structural problem like severe osteoarthritis due to its significant risks and side effects. Surgical intervention is typically preferred for functional restoration.

Question 11

A 68-year-old female presents with a closed, comminuted mid-shaft humeral fracture after a fall. She has a history of severe osteoporosis and is on anticoagulation for atrial fibrillation. She is otherwise healthy and lives independently. Given her comorbidities and fracture pattern, which treatment strategy offers the best balance of stability and minimal surgical risk?

Explanation

Correct Answer: C

For a comminuted humeral shaft fracture in an elderly patient with severe osteoporosis, achieving stable fixation is paramount. Functional bracing (Option A) is less reliable for comminuted fractures, especially in osteoporotic bone, due to the difficulty in maintaining alignment and higher risk of nonunion or malunion. A hanging cast (Option D) provides even less control over rotation and angulation than a functional brace and is generally not preferred for comminuted patterns. External fixation (Option E) is typically reserved for open fractures with significant soft tissue injury or as a temporary measure, not usually for definitive management of a closed comminuted fracture in this demographic.

Between ORIF with a locked compression plate (Option B) and antegrade intramedullary nailing (Option C), intramedullary nailing is often favored in this specific scenario. IMNs are load-sharing devices, which is advantageous in osteoporotic bone as it reduces stress shielding and the risk of implant failure compared to load-bearing plates. They provide good biomechanical stability for comminuted fractures, allow for earlier mobilization, and involve less soft tissue stripping than traditional plating, which can be beneficial in patients on anticoagulation by potentially reducing hematoma formation. While plating with a locking plate can provide angular stability in osteoporotic bone, the load-sharing nature of IMN often makes it a more robust choice for comminuted fractures in poor bone quality.

Question 12

A 35-year-old male sustains a closed, spiral mid-shaft humeral fracture. On initial presentation, he has a complete radial nerve palsy (wrist drop, inability to extend MCPs of fingers/thumb, sensory loss in radial distribution). He is initially managed with a coaptation splint. Two days later, after a gentle closed reduction attempt, his radial nerve palsy remains complete, and he develops new, severe pain with passive stretch of his fingers. What is the most appropriate next step in management?

Explanation

Correct Answer: B

This patient presents with a complex scenario involving a primary radial nerve palsy and new symptoms suggestive of a potential compartment syndrome or worsening nerve compression after a reduction attempt. While a primary radial nerve palsy associated with a closed humeral shaft fracture typically warrants observation for 3-6 months (Option A), the development of new, severe pain with passive stretch of the fingers is a hallmark symptom of impending or established forearm compartment syndrome. This, combined with the persistent complete radial nerve palsy after a reduction attempt, raises concern for nerve entrapment or further injury. An iatrogenic or worsening nerve palsy, especially after manipulation, is an absolute indication for immediate surgical exploration.

Therefore, the most appropriate next step is immediate surgical exploration of the radial nerve and ORIF of the fracture (Option B). This allows for direct visualization of the nerve to identify and address any entrapment, transection, or compression, and simultaneously provides stable fixation of the fracture. Delaying exploration (Option A, E) in this context risks irreversible nerve damage. While compartment syndrome is a concern, an MRI (Option C) is too slow for an acute emergency; clinical signs and compartment pressure measurements are more critical. Corticosteroids (Option D) are not indicated for traumatic nerve injury or compartment syndrome.

Question 13

A 50-year-old male sustains a highly comminuted mid-shaft humeral fracture with significant bone loss after a high-energy trauma. He is a heavy smoker and has poorly controlled diabetes. The surgical team decides on operative management. Which biomechanical principle is most advantageous for the chosen fixation method in this patient, aiming for reliable union despite his comorbidities?

Explanation

Correct Answer: D

For a highly comminuted humeral shaft fracture with bone loss, especially in a patient with comorbidities like smoking and diabetes that impair healing, the goal is to provide stable fixation that promotes biological healing. Intramedullary nailing (IMN) is often preferred in such cases due to its load-sharing properties (Option D). Load-sharing means the implant shares axial load with the bone, allowing for some stress at the fracture site. This intermittent stress is crucial for stimulating callus formation and secondary bone healing, which is the desired mode of healing for comminuted fractures. This is particularly important in patients with compromised healing potential.

Absolute stability for primary bone healing (Option A) is typically achieved with rigid compression plating for simple fracture patterns, but it can lead to stress shielding and delayed healing in comminuted fractures. The tension band effect (Option B) is a principle used for specific fracture types (e.g., olecranon, patella) and is not the primary biomechanical advantage for comminuted humeral shaft fractures. Load-bearing fixation (Option C) is characteristic of plates, where the plate bears most of the load, potentially leading to stress shielding and delayed union in comminuted fractures. External fixation (Option E) is primarily for open fractures or temporary stabilization, and while it allows for wound care, its biomechanical advantage for definitive healing of a closed comminuted fracture is not superior to internal fixation.

Question 14

A 42-year-old male undergoes open reduction and internal fixation of a mid-shaft humeral fracture using a posterior approach (triceps-sparing). During the procedure, the surgeon is particularly cautious when dissecting in the spiral groove. Which of the following structures is most at risk of iatrogenic injury in this specific anatomical region during this approach?

Explanation

Correct Answer: D

The radial nerve (Option D) is the structure most at risk during a posterior approach to the mid-shaft humerus, particularly when dissecting in the spiral groove. The radial nerve courses obliquely across the posterior aspect of the humerus within the spiral groove, approximately 10-14 cm proximal to the lateral epicondyle. It is intimately associated with the bone in this region, making it highly vulnerable to direct injury, traction, or compression during surgical exposure, reduction, and plate application. The triceps-sparing posterior approach aims to minimize muscle damage but still requires careful identification and protection of the radial nerve.

The Axillary nerve (Option A) is more proximal, associated with the surgical neck of the humerus. The Median nerve (Option B) and Ulnar nerve (Option C) are located more medially and anteriorly in the arm, and distally, respectively, and are not typically at direct risk with a posterior mid-shaft approach. The Musculocutaneous nerve (Option E) is located more anteriorly, between the biceps and brachialis muscles, and is at risk with anterolateral approaches, not a posterior approach to the mid-shaft.

Question 15

A 60-year-old active female develops a symptomatic hypertrophic nonunion of a mid-shaft humeral fracture 8 months after treatment with a functional brace. Radiographs show abundant callus formation but a persistent fracture line and no bridging. She reports pain with activity and limited function. What is the most appropriate surgical management?

Explanation

Correct Answer: B

A hypertrophic nonunion is characterized by abundant callus formation, indicating that the fracture site has biological healing potential but lacks sufficient mechanical stability to bridge the fracture gap. In this scenario, the primary problem is mechanical, not biological. Therefore, the most appropriate surgical management is to provide rigid mechanical stability. Intramedullary nailing (Option B) is an excellent choice for hypertrophic nonunions of the humeral shaft. It provides a load-sharing, stable construct with minimal soft tissue disruption, which is ideal for stimulating the existing biological activity to bridge the gap. Since there is already abundant callus, bone grafting (which addresses biological deficiencies) is typically not required for hypertrophic nonunions.

Re-application of a functional brace (Option A) is unlikely to be effective for an established nonunion. Open reduction and internal fixation with a plate, decortication, and autogenous bone grafting (Option C) is the gold standard for atrophic nonunions, where there is a biological deficiency and lack of callus. External fixation (Option D) is generally reserved for open fractures, infected nonunions, or as a temporary measure, not typically for definitive treatment of a closed hypertrophic nonunion. Percutaneous injection of corticosteroids (Option E) would inhibit bone healing and is contraindicated.

Question 16

A 45-year-old male undergoes antegrade intramedullary nailing for a mid-shaft humeral fracture. Six months post-operatively, he complains of persistent shoulder pain, especially with overhead activities, and limited range of motion. Radiographs confirm union of the fracture. What is the most likely cause of his ongoing shoulder symptoms?

Explanation

Correct Answer: C

A well-recognized and common complication of antegrade intramedullary nailing for humeral shaft fractures is postoperative shoulder pain, stiffness, and rotator cuff impingement (Option C). The antegrade entry point for the nail typically involves breaching the rotator cuff (supraspinatus tendon) and potentially damaging the deltoid muscle. Hardware prominence at the entry site, or direct injury to the rotator cuff during insertion, can lead to chronic pain, impingement symptoms, and restricted shoulder motion, particularly with overhead activities, even after the fracture has healed. This is a significant disadvantage of antegrade nailing.

Radial nerve irritation (Option A) is less common with IMN than with plating and would typically manifest as neurological symptoms in the forearm/hand, not shoulder pain. Nonunion (Option B) is ruled out by the question stating the fracture has united. Infection (Option D) would typically present with signs of inflammation, fever, and persistent pain, but not specifically shoulder impingement. Distal locking screw loosening (Option E) would cause pain at the fracture site or distal humerus, not typically shoulder pain or impingement.

Question 17

A 28-year-old female sustains a closed, transverse mid-shaft humeral fracture. She is treated non-operatively with a functional brace. At 6 weeks follow-up, radiographs show the fracture has healed with 18 degrees of varus angulation and 2.5 cm of shortening. She has no pain and full functional use of her arm. Which of the following statements best describes this outcome?

Explanation

Correct Answer: B

For closed humeral shaft fractures treated non-operatively, generally accepted radiographic outcomes include up to 20 degrees of angulation in any plane (varus/valgus, anterior/posterior) and up to 3 cm of shortening. In this patient, the fracture has healed with 18 degrees of varus angulation and 2.5 cm of shortening. Both of these measurements fall within the acceptable limits for non-operative management. Furthermore, the patient is asymptomatic with full functional use of her arm. Therefore, this is an acceptable outcome for non-operative management (Option B).

Options A, C, and D are incorrect because the angulation and shortening are within the accepted parameters and the patient is asymptomatic. Malunion (Option A) would imply healing in an unacceptable position, which is not the case here. Excessive shortening (Option C) or severe angulation (Option D) would be true if the measurements exceeded the 3 cm or 20-degree thresholds, respectively. Delayed union (Option E) refers to a fracture that has not healed within the expected timeframe but still shows signs of healing, which is not applicable here as the fracture has united.

Question 18

A 25-year-old male sustains a closed, transverse mid-shaft humeral fracture in a motor vehicle accident. He also has a severe traumatic brain injury (TBI) and is currently intubated and sedated in the ICU. He is expected to be non-ambulatory for an extended period. What is the optimal treatment for the humeral fracture in this polytrauma setting?

Explanation

Correct Answer: D

In a polytrauma patient, especially one with a severe traumatic brain injury (TBI) who is intubated and non-ambulatory, early and stable fixation of long bone fractures is crucial. This strategy, often referred to as 'damage control orthopedics,' aims to minimize pain, facilitate nursing care (e.g., turning, hygiene), allow for easier transfers, reduce the risk of complications like pneumonia or pressure ulcers, and potentially mitigate the systemic inflammatory response, which can positively impact TBI recovery. Non-operative methods like functional bracing (Option A) or a hanging cast (Option B) are generally unsuitable for uncooperative, sedated, or non-ambulatory TBI patients, as maintaining reduction and alignment would be extremely challenging and lead to poor outcomes.

Both open reduction and internal fixation (ORIF) with a plate (Option C) and intramedullary nailing (Option D) are viable surgical options. However, intramedullary nailing is often preferred in this setting. IMNs are load-sharing devices, which can allow for earlier protected weight-bearing and mobilization. They also involve less soft tissue dissection compared to plating, potentially reducing surgical morbidity in an already compromised patient. While plating can provide rigid fixation, IMN's load-sharing and less invasive nature often make it the optimal choice for early, stable fixation in polytrauma patients with TBI, facilitating their overall recovery and rehabilitation.

Question 19

What is the primary biomechanical advantage of a Sarmiento-type functional brace over a hanging cast for the non-operative management of a humeral shaft fracture?

Explanation

Correct Answer: B

The primary biomechanical advantage of a Sarmiento-type functional brace over a hanging cast is its ability to provide circumferential compression to the fracture site (Option B). The functional brace acts as an external pneumatic splint, using the hydraulic pressure of the surrounding soft tissues to compress the fracture fragments. This constant compression helps to maintain reduction, prevent shortening, and stimulate callus formation, thereby promoting union. Functional braces also offer better control over rotational alignment compared to hanging casts.

Hanging casts, in contrast, rely on gravity for traction and alignment. However, they provide poor rotational control and can exacerbate apex anterior angulation (sagging) if the cast is too heavy or the elbow is held in excessive flexion. While comfort (Option D) can be a factor, it's not the primary biomechanical advantage. Neither method inherently increases the risk of radial nerve palsy (Option C). While nonunion rates can be higher with improperly used hanging casts or for inappropriate fracture patterns, the core biomechanical difference lies in compression versus traction. Skin irritation (Option A) can occur with both if not properly fitted or managed.

Question 20

A 30-year-old male presents with a closed, highly displaced distal third humeral shaft fracture after a fall. Clinical examination reveals diminished radial pulse and pallor in the hand. What is the most appropriate immediate next step in management?

Explanation

Correct Answer: B

A highly displaced distal third humeral shaft fracture with signs of vascular compromise (diminished radial pulse, pallor) is a surgical emergency. The brachial artery is particularly vulnerable in the distal arm due to its close proximity to the humerus. The immediate priority is to restore blood flow to the limb. The most appropriate first step is to attempt a gentle closed reduction of the fracture (Option B). Often, the vascular compromise is due to kinking or compression of the brachial artery by the displaced fracture fragments. Reducing the fracture can decompress the artery and restore perfusion. After reduction, the vascular status must be immediately reassessed.

If the pulse returns and perfusion improves, the limb can be temporarily splinted, and definitive fixation can be planned. If the pulse does not return or perfusion remains compromised after reduction, then immediate surgical exploration of the brachial artery (Option D) is indicated to repair the vessel. An urgent CT scan (Option A) is too time-consuming for an acute vascular emergency. Antibiotics (Option C) are not the primary treatment for vascular compromise. Applying a functional brace (Option E) is inappropriate and dangerous in the setting of acute vascular compromise, as it delays critical intervention.

Question 21

A 45-year-old male presents with a pilon fracture featuring a large, displaced anterolateral (Chaput) fragment and central articular impaction. Which surgical approach provides the most direct visualization and access for reducing this specific fracture pattern?

Explanation

The anterolateral approach allows direct visualization of the Tillaux-Chaput fragment and central articular impaction. It utilizes the internervous plane between the superficial peroneal nerve and deep peroneal nerve.

Question 22

A 28-year-old male sustains a distal-third spiral humeral shaft fracture. Upon presentation, he has a dense radial nerve palsy. Closed reduction is performed, but post-reduction radiographs show an entrapped fracture fragment, and his nerve palsy persists. What is the most appropriate next step in management?

Explanation

A Holstein-Lewis fracture pattern with an entrapped fragment or a secondary radial nerve palsy developing after an attempted closed reduction are absolute indications for immediate surgical exploration. Observation is strictly reserved for primary palsies that do not worsen or present with radiographic entrapment.

Question 23

Which of the following radiographic findings is the strongest predictor of avascular necrosis (AVN) following a multi-part proximal humerus fracture?

Explanation

A medial metaphyseal hinge length of less than 8 mm, disruption of the medial periosteal hinge, and an anatomic neck fracture pattern are the most reliable predictors of ischemia and subsequent AVN. A hinge < 2 mm signifies severe disruption of the posterior humeral circumflex artery blood supply.

Question 24

When staging a high-energy pilon fracture with a spanning external fixator, a transcalcaneal pin is often utilized. To minimize the risk of injury to the posterior tibial neurovascular bundle, how should this pin be inserted?

Explanation

Transcalcaneal pins should be placed from medial to lateral to push the posterior tibial neurovascular bundle away from the advancing pin tip. The safe zone is typically 2-3 cm posterior and inferior to the medial malleolus to avoid the bundle.

Question 25

A 78-year-old female with severe rheumatoid arthritis sustains a highly comminuted, osteoporotic distal humerus fracture (AO/OTA 13-C3). She is offered a primary Total Elbow Arthroplasty (TEA). Which of the following is an expected lifelong postoperative limitation that must be counseled?

Explanation

Patients undergoing Total Elbow Arthroplasty (TEA) must be counseled to observe a lifetime lifting restriction (typically 5-10 lbs for a single event, 1-2 lbs repetitively). This is necessary to prevent accelerated polyethylene wear and catastrophic aseptic loosening of the implant.

Question 26

In the surgical management of a pilon fracture, initial internal fixation of the associated fibula fracture is commonly performed to restore limb length. In which of the following scenarios is 'fibula-first' fixation relatively contraindicated?

Explanation

If both the tibia and fibula are highly comminuted, fixing the fibula first can malreduce the fracture into valgus or incorrect length. It is safer to reconstruct the tibial articular surface first to establish the correct spatial orientation before addressing the fibula.

Question 27

During a deltopectoral approach for open reduction internal fixation of a proximal humerus fracture, excessive distal retraction of the deltoid risks injury to the axillary nerve. On average, how far distal to the lateral edge of the acromion does the axillary nerve travel?

Explanation

The axillary nerve runs transversely across the deep surface of the deltoid muscle, typically averaging 5 to 7 cm distal to the lateral edge of the acromion. Care must be taken not to split the deltoid distally beyond this point during anterolateral or deltopectoral extensions.

Question 28

A 35-year-old male sustains an intra-articular distal humerus fracture. Preoperative CT planning reveals extensive coronal shear comminution of the trochlea. Which surgical approach provides the most extensile visualization of the distal humeral articular surface?

Explanation

An olecranon osteotomy provides the highest percentage of articular visualization (up to 57%) for complex intra-articular distal humerus fractures compared to triceps-sparing or reflecting approaches. It is preferred for extensive articular comminution requiring precise anatomic reduction.

Question 29

A 40-year-old male is managed with a functional Sarmiento brace for a closed, midshaft transverse humeral fracture. At his 8-week follow-up, radiographs show a 4 mm fracture gap, 10 degrees of varus, and 15 degrees of anterior angulation. Clinically, he has gross motion at the fracture site. What is the most significant risk factor for nonunion in this patient?

Explanation

Transverse fracture patterns are at a higher risk of nonunion with functional bracing because they lack the large surface area of spiral fractures and can easily be distracted by gravity or soft tissue interposition. Angulation parameters (<20 degrees anterior, <30 degrees varus) are within acceptable limits.

Question 30

A classical four-part pilon fracture involves the medial malleolus, the anterolateral fragment, the posterolateral fragment, and the die-punch fragment. Which major ligamentous structure remains attached to the posterolateral (Volkmann's) fragment?

Explanation

The posterior inferior tibiofibular ligament (PITFL) remains solidly attached to the posterolateral (Volkmann's) fragment. In contrast, the AITFL attaches to the anterolateral (Chaput) fragment.

Question 31

Which of the following is considered an absolute indication for Reverse Total Shoulder Arthroplasty (RTSA) over Open Reduction Internal Fixation (ORIF) in the management of an acute proximal humerus fracture?

Explanation

RTSA relies on a functional deltoid rather than an intact rotator cuff to power shoulder elevation. In an elderly patient with a proximal humerus fracture and a pre-existing massive rotator cuff tear (cuff tear arthropathy), ORIF or hemiarthroplasty will fail, making RTSA the absolute treatment of choice.

Question 32

What is the most frequent late complication associated with the operative management of severe (AO/OTA 43-C3) pilon fractures despite achieving anatomic articular reduction?

Explanation

Despite anatomic reduction of the articular surface, post-traumatic osteoarthritis is the most common late complication of severe pilon fractures. This often occurs secondary to the initial irreversible chondral damage sustained at impact, and arthrodesis is frequently required in symptomatic cases.

Question 33

During the anterolateral approach to the humeral shaft, the brachialis muscle is split. To minimize the risk of denervating portions of the brachialis, how should the muscle be split?

Explanation

The brachialis muscle receives dual innervation: the medial aspect is innervated by the musculocutaneous nerve, and the lateral aspect by the radial nerve. Splitting the muscle longitudinally along its midline safely utilizes this dual innervation, preserving function on both halves.

Question 34

A 45-year-old male sustains a severe high-energy pilon fracture. He undergoes placement of an ankle-spanning external fixator on the day of injury. When assessing the patient for definitive open reduction and internal fixation (ORIF), which of the following is the most reliable clinical indicator that the soft tissues are ready?

Explanation

A positive wrinkle sign indicates resolution of significant interstitial edema and is the most reliable clinical sign that the soft tissue envelope can tolerate surgical incisions for definitive ORIF. Delaying surgery until this sign appears minimizes the risk of severe wound complications.

Question 35

During the anterolateral approach for ORIF of a pilon fracture, which neurovascular structure is at the greatest risk of iatrogenic injury during superficial dissection?

Explanation

The superficial peroneal nerve crosses the surgical field in the anterolateral approach to the distal tibia and must be carefully identified and protected. The deep peroneal nerve and anterior tibial artery lie deeper and more medial, between the tibialis anterior and extensor hallucis longus.

Question 36

A 28-year-old male sustains a closed midshaft humerus fracture and presents with an inability to extend his wrist and fingers. Sensation is decreased over the dorsal first web space. The fracture is acceptably aligned in a coaptation splint. What is the most appropriate initial management for his neurologic deficit?

Explanation

Primary radial nerve palsy in the setting of a closed humeral shaft fracture has a high rate of spontaneous recovery (up to 90%). Expectant management with observation is the standard of care, with clinical and EMG re-evaluation at 3-4 months if no recovery occurs.

Question 37

When treating a humeral shaft fracture with functional bracing (Sarmiento brace), what are the maximum acceptable radiographic parameters for angular deformity to ensure a satisfactory functional outcome?

Explanation

Acceptable alignment for humeral shaft fractures treated non-operatively includes up to 20 degrees of anterior/posterior angulation, 30 degrees of varus/valgus angulation, and up to 3 cm of shortening. The extensive range of motion of the shoulder and elbow joints compensates well for these deformities.

Question 38

In evaluating a proximal humerus fracture for the risk of avascular necrosis (AVN), which of the following radiographic findings described by Hertel et al. is the best predictor of ischemia to the humeral head?

Explanation

Hertel identified a metaphyseal head extension (calcar length) of less than 8 mm, disruption of the medial hinge, and a basicervical fracture pattern as the strongest independent predictors for humeral head ischemia and subsequent AVN.

Question 39

A 35-year-old female requires ORIF for a highly comminuted OTA/AO Type 13C3 distal humerus fracture. To maximize articular visualization, an olecranon osteotomy is planned. Which osteotomy configuration is biomechanically superior and minimizes the risk of nonunion?

Explanation

An apex-distal chevron osteotomy provides excellent articular visualization and creates a stable construct with a large surface area for healing. It is biomechanically superior to transverse osteotomies and is typically directed into the bare area of the sigmoid notch.

Question 40

In the context of a pilon fracture, the anterolateral fracture fragment of the distal tibia is commonly referred to as the Chaput fragment. Which major ligamentous structure attaches to this specific fragment?

Explanation

The Chaput fragment (anterolateral distal tibia) serves as the tibial attachment site for the Anterior Inferior Tibiofibular Ligament (AITFL). The corresponding fibular attachment of the AITFL is on the Wagstaffe fragment.

Question 41

A 40-year-old male presents with a distal third spiral humerus fracture (Holstein-Lewis type). He has an intact radial nerve exam upon presentation. Following closed reduction and splinting in the emergency department, he completely loses active wrist and finger extension. What is the most appropriate next step in management?

Explanation

A secondary radial nerve palsy that develops strictly after closed reduction of a Holstein-Lewis fracture strongly suggests iatrogenic nerve entrapment within the fracture site or lateral intermuscular septum. Immediate surgical exploration and internal fixation are indicated.

Question 42

A 75-year-old female with severe osteoporosis sustains a comminuted 4-part proximal humerus fracture with widely displaced tuberosities. Which surgical option is associated with the most predictable restoration of forward elevation and the lowest rate of functional failure in this specific demographic?

Explanation

In elderly patients with 4-part proximal humerus fractures and poor bone quality, RTSA provides more predictable forward elevation and better functional outcomes compared to hemiarthroplasty or ORIF. This is largely because RTSA relies on the deltoid rather than anatomic tuberosity healing, which is often unreliable in this cohort.

Question 43

Despite an anatomic articular reduction and successful soft tissue management, what is the most common long-term complication following operative fixation of an OTA/AO type 43C pilon fracture?

Explanation

Post-traumatic ankle osteoarthritis is the most common long-term complication after severe pilon fractures, occurring in up to 50% of cases. It develops secondary to the initial irreversible cartilage impact injury, even when anatomic articular reduction is achieved.

Question 44

A 25-year-old female sustains a coronal shear fracture of the distal humerus involving the capitellum and the lateral half of the trochlea (McKee modification of Bryan-Morrey Type IV). Which surgical approach is most appropriate for direct visualization and headless compression screw fixation?

Explanation

Coronal shear fractures involving the capitellum and lateral trochlea are best approached via an extended lateral approach (utilizing the Kocher or Kaplan interval). This allows direct anterior articular visualization for anterior-to-posterior placement of headless compression screws.

Question 45

During the staged management of a pilon fracture with an associated fibula fracture, the surgeon decides NOT to fix the fibula during the definitive tibial ORIF. Which specific fracture pattern most strongly justifies leaving the fibula unfixed to prevent secondary tibial deformity?

Explanation

In varus-impacted pilon fractures, plating the fibula out to length first can tension the lateral collateral structures and inadvertently pull the tibial block into valgus, complicating the tibial reduction. Many surgeons prefer to leave the fibula unfixed, or fix it last, in varus patterns.

Question 46

During a deltopectoral approach for a proximal humerus fracture, the cephalic vein is identified. What is the most appropriate management of the cephalic vein to protect its primary drainage while exposing the fracture?

Explanation

The cephalic vein is typically retracted laterally with the deltoid muscle during a deltopectoral approach. This protects its primary tributary branches, which predominantly arise from the deltoid, thereby minimizing the risk of avulsion and excessive bleeding.

Question 47

A 45-year-old man sustains a severe pilon fracture following a fall from height. Preoperative CT imaging demonstrates a dominant anterolateral articular fragment. Which surgical approach provides the most direct access and optimal trajectory for fixation of this specific fragment?

Explanation

The anterolateral approach utilizes the interval between the fibula and the extensor digitorum longus. It provides the most direct and optimal access to the Chaput (anterolateral) fragment of the distal tibia.

Question 48

A 28-year-old patient sustains a closed mid-shaft humeral fracture. Following application of a coaptation splint in the emergency department, the patient develops a complete wrist drop that was not present on the initial examination. What is the most appropriate next step in management?

Explanation

Radial nerve palsy after closed reduction of a humerus fracture is generally observed, as the majority are neurapraxias that resolve spontaneously. Immediate exploration is typically reserved for open fractures, associated vascular injuries, or penetrating trauma.

Question 49

When evaluating a proximal humerus fracture for the risk of avascular necrosis (AVN), which of the following Hertel criteria is the most reliable predictor of subsequent humeral head ischemia?

Explanation

Hertel's criteria for humeral head ischemia include a short metaphyseal head extension (calcar length < 8 mm), a disrupted medial hinge, and an anatomic neck fracture pattern. A disrupted medial hinge heavily compromises the medial blood supply.

Question 50

A 55-year-old female presents with a highly comminuted, closed distal humerus bicolumnar fracture (AO Type 13-C3). Which surgical approach provides the greatest exposure of the articular surface for complex open reduction and internal fixation?

Explanation

A chevron transolecranon osteotomy provides the widest and most complete visualization of the distal humeral articular surface. It is considered the gold standard for highly comminuted intra-articular fractures (Type C3).

Question 51

In the staged treatment of high-energy pilon fractures, initial spanning external fixation is followed by definitive ORIF. What is the most reliable clinical indicator that the soft tissues are ready for the definitive surgical approach?

Explanation

The appearance of the "wrinkle sign" reliably indicates that soft tissue swelling has sufficiently subsided. Proceeding with definitive surgery once this sign is present minimizes the risk of wound dehiscence and deep infection.

Question 52

A 34-year-old man falls onto an outstretched hand, sustaining a coronal shear fracture of the distal humerus involving the capitellum and extending into the trochlea (McKee modification Type IV). What is the preferred method of internal fixation?

Explanation

Headless compression screws or countersunk lag screws placed from anterior to posterior are the standard treatment for coronal shear fractures. This technique achieves rigid interfragmentary compression while burying the hardware beneath the articular cartilage.

Question 53

When performing an anterolateral approach to the distal tibia for a pilon fracture, which nervous structure crosses the surgical field and must be carefully identified and protected during the superficial dissection?

Explanation

The superficial peroneal nerve consistently crosses the anterolateral surgical field of the distal leg and ankle. It must be identified and protected to prevent painful neuromas and dorsal foot numbness.

Question 54

A 75-year-old female with osteoporosis sustains a severe 4-part proximal humerus fracture. A reverse total shoulder arthroplasty (RTSA) is chosen over a hemiarthroplasty. What is the primary functional advantage of RTSA in this specific clinical scenario?

Explanation

RTSA provides a stable, fixed fulcrum for the deltoid muscle, allowing active forward elevation even if the tuberosities (and attached rotator cuff) fail to heal or resorb. This overcomes a major cause of poor outcomes seen in hemiarthroplasty for 4-part fractures.

Question 55

In a complex pilon fracture, the posterolateral approach is often utilized to fix the posterior malleolar fragment and the fibula. What is the correct intermuscular interval utilized for this approach?

Explanation

The posterolateral approach to the distal tibia safely exploits the interval between the peroneal tendons (supplied by the superficial peroneal nerve) and the flexor hallucis longus (supplied by the tibial nerve).

Question 56

What is the maximum acceptable coronal and sagittal plane angulation for the non-operative management of a middle-third humeral shaft fracture using a Sarmiento functional brace?

Explanation

Humeral shaft fractures managed with functional bracing can tolerate up to 20 degrees of anterior/posterior angulation and 30 degrees of varus/valgus angulation. Additionally, up to 3 cm of shortening is acceptable without significant functional deficit.

Question 57

A 40-year-old male undergoes definitive ORIF of a type C pilon fracture. Three weeks postoperatively, he develops a deep wound infection over the anteromedial tibia with exposed hardware. The fracture remains unstable. What is the most appropriate next step in management?

Explanation

In the setting of an acute deep infection with exposed hardware, stable internal fixation should be retained to allow fracture healing. Aggressive serial debridements followed by early soft tissue coverage (often a free flap for the distal third of the tibia) are standard of care.

Question 58

An 82-year-old female presents with a severely comminuted intra-articular distal humerus fracture. She has multiple comorbidities, severe osteoporosis, and requires a walker for ambulation. Which of the following is the most appropriate surgical treatment?

Explanation

Total elbow arthroplasty (TEA) is highly effective for severely comminuted, osteoporotic distal humerus fractures in elderly, low-demand patients. It allows for immediate postoperative range of motion and weight-bearing through the joint.

Question 59

When repairing a proximal humerus fracture via a standard deltopectoral approach, which structure serves as the primary anatomic landmark to identify the interval between the greater and lesser tuberosities?

Explanation

The long head of the biceps tendon lies within the bicipital groove and acts as the key anatomic landmark. It separates the greater tuberosity (with its supraspinatus/infraspinatus attachments) from the lesser tuberosity (with its subscapularis attachment).

Question 60

A 25-year-old male suffers a high-energy distal tibia fracture extending into the diaphysis. Intramedullary nailing is planned. Which intraoperative technique is most critical to prevent the common complication of primary malalignment during nail passage?

Explanation

Distal tibia fractures are notoriously prone to valgus and procurvatum deformities during nailing. Poller (blocking) screws placed adjacent to the intended track of the nail help centralize the implant and maintain anatomic alignment.

Question 61

A 30-year-old presents with a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis pattern). He has an intact radial nerve pulse and normal motor function. What anatomical characteristic makes this fracture pattern prone to radial nerve injury during closed reduction?

Explanation

In a Holstein-Lewis fracture, the radial nerve is at a high risk of entrapment or laceration because it is tethered as it passes from the posterior to the anterior compartment through the lateral intermuscular septum.

Question 62

Regarding the vascular supply of the humeral head, recent quantitative cadaveric injection studies have challenged classic teaching by demonstrating that the principal blood supply to the majority of the humeral head is derived from which vessel?

Explanation

While classic teaching (Gerber et al.) emphasized the anterior circumflex humeral artery, more recent robust studies (Hettrich et al.) demonstrate that the posterior circumflex humeral artery provides the predominant blood supply (up to 64%) to the humeral head.

Question 63

During the operative fixation of a complex pilon fracture, the surgeon identifies a large "Volkmann fragment." Based on standard anatomic nomenclature, where is this fragment located?

Explanation

The Volkmann fragment refers to the posterolateral articular fragment of the distal tibia. It is the site of attachment for the posterior inferior tibiofibular ligament (PITFL).

Question 64

During a lateral approach to the distal humerus (Kocher approach) for a capitellar fracture, the surgeon must extend the dissection distally. Which nerve is at greatest risk during the distal extension of the interval between the extensor carpi ulnaris (ECU) and the anconeus?

Explanation

The posterior interosseous nerve (PIN) wraps around the radial neck within the supinator muscle. It is at significant risk of iatrogenic injury with excessive distal extension of lateral elbow approaches.

Question 65

A 45-year-old male presents with a painful atrophic nonunion of a humeral shaft fracture initially treated with a functional brace 8 months ago. What is the gold standard surgical management for this condition?

Explanation

The gold standard treatment for an atrophic humeral shaft nonunion is rigid internal fixation (typically using compression plating) combined with autologous bone grafting. This addresses both the mechanical instability and the biological deficit.

Question 66

In the definitive surgical management of severe pilon fractures, when utilizing a standard anteromedial incision for the tibia and a posterolateral incision for the fibula, what is a primary concern regarding surgical site planning?

Explanation

When performing dual incisions for pilon and fibula fractures, maintaining a sufficient skin bridge (historically recommended to be at least 7 cm) is critical to preserve angiosome perfusion. This minimizes the significant risk of wound necrosis and soft tissue breakdown.

Question 67

A 45-year-old male sustains a high-energy closed pilon fracture. Initial management consists of a spanning external fixator. Which of the following clinical signs is the most reliable indicator that the soft tissue envelope is ready for definitive open reduction and internal fixation (ORIF)?

Explanation

The return of skin wrinkling and the epithelialization of fracture blisters indicate that soft tissue swelling has subsided sufficiently to safely allow surgical incisions. Operating through swollen, tense tissue significantly increases the risk of wound dehiscence and deep infection.

Question 68

Based on the Hertel criteria, which of the following radiographic findings is the strongest predictor of humeral head ischemia in a proximal humerus fracture?

Explanation

Hertel identified a metaphyseal head extension (calcar length) of < 8 mm, disruption of the medial hinge (> 2 mm), and an anatomic neck fracture as the most reliable predictors of humeral head ischemia. A short calcar length indicates severe disruption of the critical medial blood supply.

Question 69

A 32-year-old male presents with a closed, distal third spiral fracture of the humeral shaft (Holstein-Lewis fracture). Upon initial examination in the emergency department, he is unable to extend his wrist or fingers. What is the most appropriate initial management?

Explanation

A primary radial nerve palsy in the setting of a closed humeral shaft fracture is managed nonoperatively with a coaptation splint and observation. Over 85% of primary radial nerve palsies recover spontaneously, and immediate exploration is generally reserved for open fractures or penetrating injuries.

Question 70

A 78-year-old female with osteoporosis presents with a highly comminuted, 4-part proximal humerus fracture. There is significant disruption of the medial hinge and tuberosity osteopenia. Which surgical intervention offers the most reliable functional outcome for this patient?

Explanation

In elderly patients with complex 4-part fractures and poor bone quality, rTSA provides more reliable pain relief and functional restoration compared to ORIF or hemiarthroplasty. It relies on the deltoid for motion, bypassing the frequently compromised rotator cuff and tuberosity healing issues.

Question 71

During the pre-operative CT evaluation of a complex pilon fracture, a large anterolateral articular fragment is identified. This specific fragment (Chaput fragment) is primarily stabilized by its attachment to which of the following structures?

Explanation

The anterolateral (Chaput) fragment of a pilon or ankle fracture serves as the tibial attachment site for the Anterior Inferior Tibiofibular Ligament (AITFL). Understanding these ligamentous attachments is critical for indirect reduction techniques.

Question 72

Recent quantitative anatomical studies evaluating the vascular supply to the proximal humerus have demonstrated that the predominant blood supply to the humeral head is provided by which of the following?

Explanation

While older literature emphasized the anterior circumflex humeral artery (via the arcuate artery), recent quantitative studies show that the posterior circumflex humeral artery supplies approximately 64% of the blood to the humeral head. This highlights its critical role in head viability following fracture.

Question 73

When performing an anterolateral approach to the distal tibia for the definitive fixation of a pilon fracture, which nerve is at the highest risk of iatrogenic injury during the superficial dissection?

Explanation

The superficial peroneal nerve courses through the anterolateral aspect of the distal leg and crosses the ankle joint. It is at significant risk during the superficial surgical dissection of the anterolateral approach to the distal tibia.

Question 74

A 25-year-old male sustains a closed, transverse midshaft humerus fracture. Nonoperative management with a functional fracture brace (Sarmiento) is planned. According to established criteria, what is the maximum acceptable coronal plane deformity (varus/valgus) to proceed with bracing?

Explanation

The acceptable parameters for functional bracing of a humeral shaft fracture are less than 20 degrees of anterior bowing, less than 30 degrees of varus/valgus angulation, and less than 3 cm of shortening. Deformities within these limits are generally well-tolerated functionally and cosmetically.

Question 75

Following open reduction and internal fixation of a distal humerus intra-articular fracture utilizing a Chevron olecranon osteotomy, the patient develops a complication related specifically to the osteotomy site. Which complication is most common?

Explanation

While olecranon nonunion can occur, the most common complication specifically associated with an olecranon osteotomy is symptomatic hardware (e.g., K-wires or tension band wiring) that often necessitates secondary surgery for hardware removal.

Question 76

A 55-year-old diabetic male undergoes definitive fixation of a severe open pilon fracture. Two weeks postoperatively, he presents with a 6 cm by 6 cm soft tissue defect over the anteromedial distal third of the tibia with exposed bone and hardware. What is the most reliable method for soft tissue coverage in this region?

Explanation

The distal third of the tibia lacks adequate local muscle bulk for rotational flaps. Significant soft tissue defects with exposed bone or hardware in this area typically require free tissue transfer for durable and reliable coverage.

Question 77

In the surgical treatment of proximal humerus fractures using proximal humeral locking plates, what is the most frequently reported hardware-related complication?

Explanation

Intra-articular screw penetration, often due to varus collapse of the humeral head or avascular necrosis post-fixation, is the most common hardware-related complication of locked plating in the proximal humerus.

Question 78

A 40-year-old female undergoes open reduction and internal fixation of a Type IV (Dubberley) capitellum fracture via an extensile lateral approach. Which associated soft tissue injury is frequently encountered and must be addressed to restore elbow stability?

Explanation

Complex capitellum and trochlea shear fractures are frequently associated with injury to the lateral collateral ligament complex, specifically the lateral ulnar collateral ligament (LUCL). Repairing the LUCL is crucial to prevent posterolateral rotatory instability.

Question 79

A meta-analysis comparing intramedullary nailing (IMN) versus dynamic compression plating (DCP) for humeral shaft fractures shows similar rates of union. However, intramedullary nailing is associated with a significantly higher incidence of which complication?

Explanation

Intramedullary nailing of the humerus, particularly with antegrade insertion, is associated with a significantly higher rate of shoulder morbidity, including pain, stiffness, and rotator cuff pathology, compared to plate fixation.

Question 80

During the posterolateral approach to the distal tibia for a posterior pilon fracture, the deep dissection is carried out through an internervous/intermuscular plane. Which two structures define this deep interval?

Explanation

The posterolateral approach to the ankle utilizes the interval between the flexor hallucis longus (FHL) medially and the peroneal tendons laterally. Retracting the FHL medially protects the posteromedial neurovascular bundle.

Question 81

Which of the following scenarios represents an absolute indication for operative internal fixation of an acute humeral shaft fracture?

Explanation

Absolute indications for operative stabilization of a humeral shaft fracture include an associated vascular injury requiring repair, open fractures, floating elbow, and compartment syndrome. Primary radial nerve palsy alone is a relative, not absolute, indication.

Question 82

A 28-year-old male undergoes successful ORIF of a severe pilon fracture with anatomic restoration of the joint surface. Five years later, he develops symptomatic ankle osteoarthritis. What is the primary etiologic factor for the development of post-traumatic arthritis in this patient?

Explanation

Even with perfect anatomic reduction, pilon fractures have a high rate of post-traumatic arthritis. This is primarily due to the irreversible damage sustained by the articular cartilage chondrocytes at the moment of the high-energy axial impact.

Question 83

A 19-year-old male sustains a 'floating elbow' injury consisting of a displaced midshaft humerus fracture and ipsilateral displaced both-bone forearm fractures. What is the standard of care for the humeral component of this injury?

Explanation

A 'floating elbow' (ipsilateral humerus and forearm fractures) is an absolute indication for operative fixation of both the humerus and forearm. Stabilization is required to allow early mobilization and prevent severe joint stiffness.

Question 84

According to the principles of parallel plating for distal humerus fractures outlined by O'Driscoll, how should the screws traversing the distal articular fragments be oriented to maximize biomechanical stability?

Explanation

O'Driscoll's principles of parallel plating emphasize that the distal screws should interlock or interdigitate, capturing the articular fragments from both the medial and lateral columns to create a robust, stable structural arch.

Question 85

When performing ORIF for a complex distal humerus fracture, the management of the ulnar nerve is debated. According to recent randomized controlled trials, how does routine anterior transposition of the ulnar nerve compare to in situ decompression?

Explanation

Recent studies suggest that routine anterior transposition of the ulnar nerve during distal humerus ORIF increases the incidence of postoperative ulnar neuritis. Therefore, leaving the nerve in situ after releasing compression points is often preferred unless hardware placement demands transposition.

Question 86

In the context of a pilon fracture, the 'Volkmann fragment' refers to the posterior malleolar component. This fragment is rigidly attached to the fibula via which ligamentous structure?

Explanation

The Volkmann fragment is the posterolateral articular fragment of the tibial plafond. It is strongly attached to the distal fibula by the Posterior Inferior Tibiofibular Ligament (PITFL), often moving in concert with the fibula during reduction.

ABOS Part I Orthopedic Surgery Review: Trauma, Foot & Ankle, & Oncology MCQs | Part 22213

ABOS Part I & AAOS OITE Orthopedic Surgery Review: Pilon & Humeral Fractures | Part 21582

Key Takeaway

ABOS Part I & AAOS OITE Orthopedic Surgery Review: Pilon & Humeral Fractures | Part 21582

Chapter Index