Orthopedic Board Review MCQs: Fracture, Knee & Trauma

Question 1

A 28-year-old male is brought to the emergency department after a high-speed motorcycle collision. He is diagnosed with a KD III multi-ligament knee injury. His foot is warm and pink, with palpable but diminished dorsalis pedis and posterior tibial pulses. The Ankle-Brachial Index (ABI) of the injured extremity is measured at 0.82, while the contralateral side is 1.0. What is the most appropriate next step in management?

Explanation

Current guidelines for the management of suspected vascular injury following knee dislocation recommend measuring the Ankle-Brachial Index (ABI). An ABI of less than 0.90 is highly sensitive and specific for an arterial injury requiring intervention, and warrants an immediate CT angiogram (CTA). Immediate surgical exploration is indicated for 'hard signs' of vascular injury, such as absent pulses, active hemorrhage, expanding hematoma, or distal ischemia. Serial ABIs are appropriate only if the initial ABI is > 0.90.

Question 2

A 45-year-old man undergoes open reduction and internal fixation of a Schatzker VI tibial plateau fracture. In the recovery room, he complains of severe, unrelenting pain out of proportion to the injury, significantly worsened by passive stretch of the hallux. His blood pressure is 110/70 mmHg. Intracompartmental pressure monitoring of the anterior compartment reveals a pressure of 45 mmHg. What is the most appropriate management?

Explanation

The patient is exhibiting clinical signs of acute compartment syndrome. The diagnosis is confirmed by calculating the delta pressure (Diastolic Blood Pressure minus Intracompartmental Pressure). His diastolic BP is 70 mmHg and his compartment pressure is 45 mmHg, yielding a delta pressure of 25 mmHg. A delta pressure less than 30 mmHg is an absolute indication for emergent four-compartment fasciotomy. Elevation of the limb decreases arterial perfusion and is contraindicated. Releasing dressings is a necessary initial step, but given the critical delta pressure and clinical signs, definitive surgical decompression cannot be delayed.

Question 3

An 82-year-old female sustains a highly comminuted extra-articular distal femur fracture (OTA/AO 33-A3). She is treated with a lateral locking plate using a bridge plating technique. Which of the following technical factors most significantly increases the risk of hypertrophic nonunion due to an overly stiff construct?

Explanation

In bridge plating of comminuted fractures, relative stability is desired to promote secondary bone healing (callus formation). The construct must allow for micro-motion at the fracture site to generate the optimal strain for callus formation (between 2% and 10%). Placing locking screws immediately adjacent to the fracture site significantly decreases the 'working length' of the plate, creating an overly stiff construct. This extreme rigidity decreases interfragmentary strain below the threshold required for callus formation, increasing the risk of delayed union, nonunion, or eventual hardware failure.

Question 4

A 35-year-old male sustains an Anterior-Posterior Compression type II (APC-II) pelvic ring injury following a crush injury at a construction site. On arrival, he is hemodynamically unstable despite initial fluid resuscitation. What is the most common anatomic source of major hemorrhage in this type of injury?

Explanation

While arterial bleeding (such as from the superior gluteal or internal pudendal arteries) can cause rapid, life-threatening exsanguination and is the target for pelvic angioembolization, the most common overall source of hemorrhage in pelvic ring fractures is venous bleeding from the presacral venous plexus and the exposed cancellous bone surfaces. This low-pressure bleeding is typically managed initially by reducing pelvic volume (e.g., pelvic binder) to promote tamponade.

Question 5

A 40-year-old male sustains a high-energy Gustilo-Anderson IIIB open fracture of the distal third of the tibia. After aggressive surgical debridement and application of an external fixator, a 5 cm x 8 cm soft tissue defect with exposed denuded bone remains. Which of the following soft tissue coverage options provides the most reliable and robust vascularized coverage for this specific anatomical region?

Explanation

Soft tissue coverage for the tibia is classically divided into thirds. The proximal third is typically covered by a medial or lateral gastrocnemius rotational flap. The middle third is covered by a soleus rotational flap. The distal third, due to limited local muscle bulk, generally requires a free tissue transfer (such as a latissimus dorsi, rectus abdominis, or gracilis muscle free flap) for reliable coverage, especially in high-energy Gustilo IIIB injuries. While the reverse sural flap is an option for smaller defects, a free vascularized muscle flap is the most reliable choice for a defect of this size with exposed bone.

Question 6

A 26-year-old female sustains a vertical, transcervical femoral neck fracture (Pauwels Type III) following a fall from a horse. Which of the following internal fixation constructs provides the greatest biomechanical resistance to vertical shear forces for this fracture pattern?

Explanation

Pauwels Type III femoral neck fractures have a vertical orientation (>50 degrees), which subjects the fracture site to exceptionally high shear forces rather than compressive forces. Biomechanical studies demonstrate that a fixed-angle construct, such as a sliding hip screw (dynamic hip screw, DHS), provides superior resistance to vertical shear forces compared to multiple parallel cancellous screws. An anti-rotation screw is often added to prevent rotation of the femoral head during insertion and subsequent loading. Parallel cancellous screws are primarily indicated for more horizontal fractures (Pauwels I or II) where compressive forces predominate.

Question 7

When counseling a 20-year-old athlete regarding anterior cruciate ligament (ACL) reconstruction, you discuss the biomechanical properties of different autografts. Which of the following statements accurately compares the biomechanical characteristics of a quadrupled (4-strand) hamstring autograft to the native ACL?

Explanation

Biomechanical studies have shown that a quadrupled (4-strand) hamstring tendon graft has an ultimate load to failure of approximately 4090 N and a stiffness of 776 N/mm. In contrast, the native ACL has an ultimate load to failure of roughly 2160 N and a stiffness of 242 N/mm. A 10-mm bone-patellar tendon-bone (BPTB) graft has an ultimate load of ~2977 N and a stiffness of ~620 N/mm. Therefore, the 4-strand hamstring autograft has both a significantly higher ultimate load to failure and higher stiffness compared to the native ACL.

Question 8

A 28-year-old male presents with chronic knee instability following a football injury 9 months ago. Physical examination reveals a positive Lachman test, a positive pivot shift, and significant laxity to varus stress at 30 degrees of flexion. His dial test is asymmetric at 30 and 90 degrees. Standing full-length radiographs demonstrate a mechanical axis passing through the medial compartment (varus morphotype). What is the most appropriate initial surgical management?

Explanation

In the setting of chronic combined ACL and posterolateral corner (PLC) deficiency coupled with varus mechanical alignment, performing ligamentous reconstruction alone without addressing the bony malalignment results in exceptionally high failure rates due to excessive tensile forces on the grafts. The standard of care is a staged approach: an initial High Tibial Osteotomy (HTO) to correct the varus alignment (shifting the mechanical axis laterally), followed by delayed ACL/PLC reconstruction. Often, the bony correction provides sufficient stability that the patient may not require the second-stage ligament reconstruction.

Question 9

A polytrauma patient with a femur fracture, blunt chest trauma, and a closed head injury has been resuscitated over the past 24 hours. The trauma team is evaluating whether the patient is physiologically ready for transitioning from "Damage Control Orthopedics" (DCO) to definitive fracture fixation ("Early Total Care"). Normalization of which of the following physiological parameters is the most reliable indicator of adequate resuscitation?

Explanation

The decision to convert from damage control orthopedics to definitive fracture care relies heavily on the normalization of systemic perfusion and the clearance of shock markers. A normalized serum lactate (< 2.0 mmol/L) and a base excess resolving to within normal limits (-2 to +2 mEq/L) are the most widely accepted and reliable biochemical markers indicating adequate resuscitation and restoration of tissue perfusion, thereby minimizing the 'second hit' phenomenon associated with definitive surgical intervention.

Question 10

A 65-year-old osteoporotic female undergoes open reduction and internal fixation of a 3-part proximal humerus fracture using a fixed-angle locking plate. To minimize the risk of post-operative varus collapse and subsequent intra-articular screw penetration, which specific technical maneuver is most critical during fixation?

Explanation

In the operative management of proximal humerus fractures with locking plates, the loss of medial support (the medial hinge) is a primary risk factor for failure via varus collapse and screw cut-out. Placement of a well-positioned inferomedial locking screw (the 'calcar screw') into the inferomedial quadrant of the humeral head mechanically supports the medial cortex and significantly increases the biomechanical resistance to varus loads, thereby preventing construct failure.

Question 11

A 10-year-old boy falls while skiing and sustains a Type III tibial eminence fracture. He undergoes successful arthroscopic reduction and internal fixation. During his postoperative course, which of the following is the most common complication associated with this injury and its surgical treatment?

Explanation

Arthrofibrosis (post-operative stiffness) is the most frequent complication following both non-operative and operative management of tibial eminence fractures in pediatric patients. While minor residual laxity may be detectable on objective testing (such as KT-1000 measurements), clinical instability is rare. Early physical therapy emphasizing range of motion is crucial to prevent stiffness. Physeal arrest is a rare complication if proper surgical technique (avoiding fixation across the physis) is utilized.

Question 12

A 4-year-old boy presents with an isolated spiral midshaft femur fracture after falling from a playground slide. Radiographs reveal 1.5 cm of shortening and 10 degrees of varus angulation. There is no evidence of non-accidental trauma. What is the most appropriate definitive management for this patient?

Explanation

For pediatric diaphyseal femur fractures, treatment algorithms are heavily based on age. Children aged 6 months to 5 years with an isolated femur fracture and < 2 cm of shortening are definitively treated with early closed reduction and hip spica casting. Pavlik harnesses are typically reserved for infants < 6 months of age. Flexible intramedullary nails (Elastic Stable Intramedullary Nailing, ESIN) are the treatment of choice for children aged 5 to 11 years. Rigid intramedullary nailing is contraindicated in young children due to the risk of avascular necrosis of the femoral head and greater trochanteric apophyseal arrest.

Question 13

A 32-year-old male sustains a high-energy axial load injury to his foot resulting in a Hawkins Type III fracture of the talar neck. Based on the Hawkins classification system, which specific joints are disrupted in this injury pattern?

Explanation

The Hawkins classification of talar neck fractures predicts the risk of avascular necrosis based on the degree of dislocation. Type I is a nondisplaced fracture. Type II is a displaced fracture with subluxation or dislocation of the subtalar joint (the tibiotalar and talonavicular joints remain congruent). Type III is a displaced fracture with dislocation of both the subtalar and tibiotalar joints (the talar body extrudes, often posteriorly). Type IV (added by Canale and Kelly) involves dislocation of the subtalar, tibiotalar, and talonavicular joints.

Question 14

A 25-year-old male undergoes a primary anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft. Seven months postoperatively, he complains of localized anterior knee pain, an audible 'clunk,' and a mechanical block to terminal extension (lacks 15 degrees). MRI demonstrates a nodular, heterogeneous mass anterior to the tibial tunnel in the intercondylar notch. What technical error during the initial surgery most directly caused this complication?

Explanation

The patient has developed a 'cyclops lesion,' which is a localized form of anterior arthrofibrosis consisting of a fibrovascular nodule that forms anterior to the ACL graft. Clinically, it presents with a loss of terminal knee extension and sometimes an audible clunk. The primary technical error associated with the formation of a cyclops lesion is placing the tibial tunnel too far anteriorly. This anterior placement causes the graft to impinge against the roof of the intercondylar notch (Blumensaat's line) during terminal extension, leading to repetitive microtrauma, fraying of the graft, and subsequent reactive fibrous tissue proliferation.

Question 15

A 52-year-old male presents with a severely displaced, intra-articular calcaneus fracture (Sanders Type III) after falling from a ladder. His past medical history is significant for poorly controlled Type 2 Diabetes Mellitus (HbA1c 9.5%), peripheral neuropathy, and smoking 2 packs of cigarettes per day. His soft tissues are significantly swollen with fracture blisters over the lateral hindfoot. What is the most appropriate management strategy for this patient?

Explanation

This patient possesses multiple severe risk factors for devastating soft tissue complications following an extensile lateral approach to the calcaneus, specifically heavy smoking and uncontrolled diabetes with neuropathy. In such high-risk patients, the incidence of wound necrosis, deep infection, and subsequent amputation following operative fixation is unacceptably high. Therefore, conservative management is indicated. The preferred non-operative protocol involves early, aggressive range of motion exercises without casting (to maximize subtalar mobility) and strict non-weight-bearing until clinical and radiographic healing occurs.

Question 16

A 48-year-old female sustains a closed, high-energy tibial pilon fracture (OTA/AO 43-C3) in a motor vehicle collision. On arrival, her distal lower extremity is grossly deformed, excessively swollen, and taut, with early hemorrhagic fracture blisters forming. She is hemodynamically stable. What is the most appropriate initial orthopedic intervention?

Explanation

High-energy tibial pilon fractures are associated with profound soft tissue injury. Immediate definitive fixation (ORIF) in the presence of severe swelling and fracture blisters is associated with extremely high rates of wound dehiscence and deep infection. The standard of care is a staged protocol ('span, scan, and plan'): immediate application of a spanning external fixator across the ankle joint to restore length, alignment, and provide stability, allowing the soft tissues to declare themselves and swellings to subside over 10-21 days before definitive internal fixation is attempted.

Question 17

During the pathophysiological development of acute compartment syndrome following a severe closed tibial shaft fracture, what is the initial microvascular event that initiates the cascade leading to muscle and nerve ischemia?

Explanation

Acute compartment syndrome develops when the pressure within a closed fascial space increases. The initial microvascular event is the compression of thin-walled post-capillary venules, causing venous outflow obstruction. This lack of venous egress leads to engorgement of the capillary bed, further increasing intracompartmental pressure. Once the tissue pressure exceeds the capillary perfusion pressure (which is closely tied to diastolic blood pressure), capillary flow ceases, resulting in cellular hypoxia and ischemia. Major arterial flow is typically maintained until very late in the process, which is why distal pulses are notoriously unreliable for ruling out compartment syndrome.

Question 18

A 19-year-old female dancer presents with recurrent lateral patellar instability. An MRI of her knee reveals a Tibial Tubercle to Trochlear Groove (TT-TG) distance of 23 mm, a Caton-Deschamps index of 1.0, and a Dejour Type A trochlear dysplasia. She has failed conservative management. Which of the following surgical procedures is most appropriate to minimize her risk of recurrence?

Explanation

The patient has recurrent patellar instability with an abnormally high TT-TG distance. A normal TT-TG distance is generally < 15 mm. A distance of > 20 mm is considered pathologic and is an absolute indication for a medializing tibial tubercle osteotomy (TTO) to centralize the extensor mechanism. Performing an isolated MPFL reconstruction in the setting of a TT-TG > 20 mm subjects the graft to excessive lateralizing forces, resulting in an unacceptably high rate of graft failure. Because her Caton-Deschamps index is 1.0 (normal patellar height), a distalizing TTO is not indicated.

Question 19

A 55-year-old female feels a sudden 'pop' in the posterior aspect of her knee while descending stairs. She complains of intense posteromedial knee pain. An MRI reveals >3 mm of medial meniscal extrusion on the coronal sequence and a 'ghost sign' on the sagittal sequence. This specific meniscal injury pattern is most strongly associated with the subsequent development of which of the following conditions if left untreated?

Explanation

The clinical presentation and MRI findings (extrusion > 3 mm, 'ghost sign') are pathognomonic for a medial meniscus posterior root tear. The posterior root anchor is essential for converting axial loads into hoop stresses. Disruption of the root biomechanically mimics a total meniscectomy, leading to drastically increased focal contact pressures in the medial compartment. If left untreated, this rapid loss of load distribution is highly associated with the development of a subchondral insufficiency fracture of the knee (SIFK), classically referred to as spontaneous osteonecrosis of the knee (SONK), and rapid progression of osteoarthritis.

Question 20

A 22-year-old farm worker sustains a severely contaminated open tibia fracture (Gustilo-Anderson IIIA) after his leg becomes trapped in a soil-tilling machine. He has no known drug allergies. According to current evidence-based guidelines and classical orthopaedic teaching, which of the following is the most appropriate prophylactic intravenous antibiotic regimen to administer upon emergency department presentation?

Explanation

For severe open fractures (Gustilo Type III), standard prophylaxis includes gram-positive coverage (first-generation cephalosporin, like cefazolin) and expanded gram-negative coverage (an aminoglycoside, like gentamicin, or alternatively a third-generation cephalosporin like ceftriaxone). However, in the setting of farm-related injuries, gross soil contamination, or potential ischemic tissue (such as high-energy crush injuries), there is a significant risk for anaerobic infection, specifically Clostridium perfringens (which causes gas gangrene). Therefore, the classic and standard board-tested recommendation is to add high-dose penicillin to the regimen to provide robust anaerobic coverage.

Question 21

A 42-year-old male sustains a severe Schatzker VI tibial plateau fracture in a high-speed motor vehicle collision. He is intubated in the intensive care unit. Which of the following continuous compartment pressure readings definitively indicates the need for a four-compartment fasciotomy?

Explanation

The most reliable threshold for diagnosing acute compartment syndrome in a polytrauma or obtunded patient is a Delta P (Diastolic Blood Pressure minus Compartment Pressure) of less than 30 mmHg. Relying on absolute pressure alone (e.g., > 30 mmHg) can lead to unnecessary fasciotomies, especially in hypertensive patients, or missed diagnoses in hypotensive patients.

Question 22

When using an intramedullary nail for a proximal third extra-articular tibia fracture, the fracture classically displaces into an apex anterior (procurvatum) and valgus deformity. To prevent this deformity using blocking screws (Poller screws) in the proximal segment, where should the screws be placed relative to the intended path of the intramedullary nail?

Explanation

Blocking screws narrow the medullary canal and guide the path of the intramedullary nail. They should be placed on the concave side of the expected deformity. To prevent an apex anterior (procurvatum) deformity, the screw is placed posterior to the nail in the proximal fragment. To prevent a valgus (apex medial) deformity, the screw is placed lateral to the nail. Therefore, the correct placement is posterior and lateral.

Question 23

A 28-year-old male presents with a grossly deformed knee following a motorcycle crash. Plain radiographs reveal an anterior knee dislocation (KD-III). Following closed reduction, his dorsalis pedis and posterior tibial pulses are palpable and symmetric to the contralateral side. An Ankle-Brachial Index (ABI) is measured at 0.82. What is the most appropriate next step in management?

Explanation

In the setting of a knee dislocation, vascular assessment is critical. While palpable pulses are reassuring, an ABI < 0.9 is highly sensitive for an occult arterial injury and mandates further advanced vascular imaging, most commonly a CT angiogram (CTA). Immediate surgical exploration is reserved for hard signs of vascular injury (e.g., absent pulses after reduction, expanding hematoma, pulsatile bleeding).

Question 24

A 45-year-old female sustains a bicondylar tibial plateau fracture with a significant, displaced posteromedial shear fragment. A posteromedial surgical approach is planned to buttress this fragment. Which intermuscular interval is utilized for the standard posteromedial approach to the tibial plateau?

Explanation

The standard posteromedial approach to the knee for tibial plateau fractures utilizes the interval between the medial head of the gastrocnemius and the semimembranosus. Retracting the medial gastrocnemius laterally protects the neurovascular bundle in the popliteal fossa.

Question 25

A 32-year-old male undergoes open reduction and internal fixation of a transverse patella fracture utilizing a standard anterior tension band wiring construct. Biomechanically, this construct achieves stability and promotes healing by converting which of the following forces into articular compression?

Explanation

The tension band principle relies on placing a tension band on the convex (tension) side of a bone. For the patella, during knee flexion, the anterior cortex experiences tensile forces while the articular (posterior) surface experiences compressive forces. An anteriorly placed tension band wire resists these tensile forces and converts them into compressive forces across the articular surface, enhancing stability and healing.

Question 26

A 55-year-old male with end-stage renal disease presents with acute anterior knee pain and an inability to perform a straight leg raise after a slip and fall. Lateral radiographs of the knee demonstrate a patella baja (low-riding patella) with an Insall-Salvati ratio of 0.6. Which of the following is the most likely diagnosis?

Explanation

An inability to perform a straight leg raise indicates disruption of the extensor mechanism. A low-riding patella (patella baja), evidenced by an Insall-Salvati ratio < 0.8, points to a quadriceps tendon rupture, as the intact patellar tendon tethers the patella distally. A patellar tendon rupture would result in a high-riding patella (patella alta).

Question 27

A 25-year-old male polytrauma patient is diagnosed with a Type IIa Fraser floating knee (transverse diaphyseal femur fracture and intra-articular proximal tibia fracture). Both injuries require operative fixation. What is the generally recommended sequence of fixation to optimize alignment and knee biomechanics?

Explanation

In a Type IIa floating knee (femoral shaft + tibial plateau), the recommended sequence is typically to fix the femoral shaft first. This provides a stable reference limb to appropriately judge alignment and length when reconstructing the articular surface of the tibial plateau, and prevents displacing a newly fixed plateau while manipulating the femur. (Note: If both were intra-articular [Type IIc], the articular surfaces must be reconstructed prior to diaphyseal components).

Question 28

A 78-year-old female presents with a displaced, closed supracondylar femur fracture just above a well-fixed posterior-stabilized total knee arthroplasty (TKA). Operative reports confirm the implant is a 'closed box' design. Which of the following is the most appropriate initial fixation strategy?

Explanation

A posterior-stabilized (PS) total knee arthroplasty with a 'closed box' design prevents the passage of a retrograde intramedullary nail through the intercondylar notch. Given the implant is well-fixed, lateral locked plating is the most appropriate fixation strategy for this periprosthetic supracondylar femur fracture.

Question 29

A 33-year-old male sustains an isolated coronal shear fracture of the lateral femoral condyle (Hoffa fracture). Open reduction and internal fixation is planned. Regarding interfragmentary lag screw fixation, which configuration offers the greatest biomechanical stiffness and resistance to pullout for this specific fracture pattern?

Explanation

Biomechanical studies (e.g., Jarit et al.) have demonstrated that posterior-to-anterior (PA) lag screws provide significantly greater construct stiffness, higher load to failure, and better resistance to pullout compared to anterior-to-posterior (AP) screws for Hoffa fractures, primarily because the posterior bone is denser and offers better thread purchase.

Question 30

A 14-year-old boy presents with a displaced tibial tubercle avulsion fracture (Ogden Type III) sustained while jumping during a basketball game. Over the next 4 hours, he complains of escalating, severe pain in his anterior leg, with pain elicited on passive plantarflexion of the toes. Which vascular structure is most commonly injured in this scenario, contributing to this sight-threatening complication?

Explanation

Tibial tubercle avulsion fractures, especially when displaced, carry a high risk of acute anterior compartment syndrome. This is frequently caused by disruption and bleeding from the anterior tibial recurrent artery, which is intimately associated with the proximal tibia and extensor mechanism near the tubercle.

Question 31

A 30-year-old male is evaluated for knee instability following a wrestling injury. A Dial test is performed in the prone position. There is 20 degrees of increased external rotation at 30 degrees of knee flexion compared to the contralateral side. At 90 degrees of knee flexion, the external rotation is symmetric bilaterally. Which structure(s) are primarily injured?

Explanation

The Dial test evaluates posterolateral rotatory instability. Increased external rotation (>10 degrees compared to the normal knee) at 30 degrees of flexion, but normal at 90 degrees, indicates an isolated injury to the posterolateral corner (PLC). If increased external rotation is present at both 30 and 90 degrees, it indicates a combined injury to the PLC and the posterior cruciate ligament (PCL).

Question 32

A 12-year-old female sustains a completely displaced tibial eminence fracture (Meyers and McKeever Type III) after a skiing accident. Closed reduction under general anesthesia is attempted but is unsuccessful due to an intra-articular block to reduction. What is the most common anatomic structure blocking the reduction of this fracture?

Explanation

In completely displaced tibial eminence (tibial spine) fractures (Meyers and McKeever Type III), the anterior horn of the medial meniscus frequently becomes entrapped beneath the avulsed bony fragment, preventing anatomic reduction and necessitating arthroscopic or open reduction.

Question 33

A 35-year-old male sustains a Gustilo-Anderson Type IIIB open fracture of the proximal third of the tibia with significant anterior soft tissue loss. Following aggressive serial debridements and skeletal stabilization, soft tissue coverage is required. Which of the following is the most appropriate reliable local muscle flap option for this defect?

Explanation

For soft tissue coverage of the lower extremity, local rotational flaps are often selected based on the zone of injury. Defects of the proximal third of the tibia are classically covered with a medial (or lateral) gastrocnemius rotational flap. The middle third typically utilizes a soleus flap, while the distal third generally requires a free tissue transfer.

Question 34

A 28-year-old male requires open reduction and internal fixation of a large, displaced tibial-sided avulsion fracture of the posterior cruciate ligament (PCL). A traditional posteromedial approach to the knee is planned. The deep surgical dissection passes between the medial head of the gastrocnemius and which other muscle to expose the posterior capsule?

Explanation

The posteromedial approach to the knee (often attributed to Burks and Schaffer) relies on the internervous/intermuscular plane between the medial head of the gastrocnemius (tibial nerve) and the semimembranosus (sciatic nerve). Retracting the gastrocnemius laterally protects the midline neurovascular structures.

Question 35

Nine months after lateral locked plating of a comminuted distal femur fracture (AO/OTA 33-A3), a 65-year-old patient presents with new-onset thigh pain. Radiographs reveal a broken lateral plate at the fracture site, varus collapse, and a persistent medial cortical void. What biomechanical principle of locked plating was most likely violated, contributing to this fatigue failure?

Explanation

A common cause of locked plate failure in comminuted fractures with a medial void is a working length that is too short. A short working length increases the stiffness of the construct, which concentrates stress onto a short segment of the plate over the nonunion site, ultimately leading to cyclic fatigue failure and plate breakage. A longer working length allows the construct to distribute strain over a larger area.

Question 36

Following a high-energy closed proximal tibia fracture, a patient develops acute compartment syndrome. Which of the following compartments is most frequently affected, and what physical examination finding is widely considered its most sensitive early clinical indicator?

Explanation

The anterior compartment of the leg is the most commonly affected compartment in acute compartment syndrome following tibia fractures. The most sensitive and reliable early clinical indicator is pain out of proportion to the apparent injury, classically exacerbated by passive stretch of the muscles in that compartment (e.g., passive plantarflexion of the toes stretching the anterior compartment muscles). Pulselessness and paralysis (e.g., foot drop) are very late and often irreversible signs.

Question 37

A 40-year-old male sustains an acute, traumatic knee dislocation (KD-IV) complicated by an incomplete common peroneal nerve palsy at presentation. Pulses are symmetric and ABI is 1.0. What is the expected prognosis of this specific nerve injury, and what is the most appropriate initial management?

Explanation

Common peroneal nerve palsy following knee dislocation is typically a high-grade traction injury. While incomplete lesions have a better prognosis than complete lesions, overall functional recovery remains variable and frequently poor (about 20-40% full recovery). Initial management consists of observation, physical therapy to prevent contractures, and an AFO. Tendon transfers or nerve grafting are generally reserved for persistent deficits at 6 to 12 months.

Question 38

A 60-year-old male with a history of recurrent periprosthetic joint infections following a total knee arthroplasty ultimately requires a definitive knee arthrodesis. To optimize the patient's postoperative gait kinematics, energy expenditure, and clearance during the swing phase, what is the generally accepted ideal position for the knee fusion?

Explanation

The optimal position for a knee arthrodesis balances limb length, foot clearance, and energy efficiency during gait. The recommended position is 10 to 15 degrees of flexion (facilitates swing phase clearance and sitting), 5 to 7 degrees of physiologic valgus, and 0 to 10 degrees of external rotation to match the normal mechanical axis of the limb.

Question 39

A 50-year-old male presents with a Schatzker Type IV (medial) tibial plateau fracture. Compared to a low-energy Schatzker Type II (lateral split-depression) fracture, this fracture pattern has a significantly higher association with which of the following concomitant injuries?

Explanation

A Schatzker Type IV fracture involves the medial plateau and is typically a high-energy, varus-directed injury. Because the medial plateau is structurally denser than the lateral side, it requires substantial force to fracture. Consequently, Schatzker IV fractures are often considered 'knee dislocation equivalents' and carry a significantly higher risk of popliteal artery injury and disruption of the lateral soft tissue structures (LCL, posterolateral corner) compared to Schatzker II fractures.

Question 40

A 24-year-old male presents with bilateral closed femoral shaft fractures and a pulmonary contusion following a high-speed motorcycle crash. His initial blood pressure is 90/60 mmHg, heart rate is 120 bpm, and base deficit is -8. Resuscitation improves his vitals marginally, but base deficit remains -6. According to the principles of Damage Control Orthopedics (DCO), which of the following is the most appropriate initial management for his femur fractures?

Explanation

This patient is hemodynamically 'borderline' or 'unstable' (persistent high base deficit, bilateral femur fractures, chest trauma). According to Damage Control Orthopedics (DCO) principles, early definitive care (Early Total Care - ETC) with intramedullary nailing poses an unacceptable risk of a 'second hit' (e.g., ARDS, fat embolism, multi-organ failure). Rapid temporary stabilization with external fixation limits ongoing hemorrhage and systemic inflammatory response, with planned conversion to definitive IM nailing once physiology normalizes.

Question 41

A 32-year-old male undergoes intramedullary nailing of a proximal-third tibial shaft fracture using a standard infrapatellar approach. Which of the following malalignments is most commonly associated with this specific technique for this fracture pattern?

Explanation

Proximal third tibial fractures treated with infrapatellar intramedullary nailing commonly fall into an apex anterior (procurvatum) and valgus deformity. This is due to the pull of the patellar tendon and the medial starting point of the nail.

Question 42

A 25-year-old male presents with an obvious knee deformity following a high-energy rugby tackle. Physical examination reveals a transverse skin furrow (dimple sign) over the medial joint line. Closed reduction is attempted but is unsuccessful. What is the most likely anatomic block to reduction?

Explanation

The "dimple sign" is pathognomonic for an irreducible posterolateral knee dislocation. It is caused by the medial femoral condyle buttonholing through the anteromedial joint capsule, necessitating an open reduction.

Question 43

A 40-year-old female sustains a bicondylar tibial plateau fracture (Schatzker VI). CT imaging demonstrates a large, displaced posteromedial coronal split fragment. When planning surgical fixation, what is the most appropriate approach and fixation strategy for this specific fragment?

Explanation

Displaced posteromedial coronal fragments in tibial plateau fractures are best treated with a posteromedial approach and an under-contoured antiglide plate. Laterally applied locking plates often fail to adequately capture or buttress this fragment.

Question 44

A 35-year-old male sustains a distal femur fracture. CT imaging reveals a coronal plane fracture of the lateral femoral condyle. Which of the following describes the optimal biomechanical fixation construct for this specific fracture pattern?

Explanation

A Hoffa fracture (coronal split of the femoral condyle) is optimally fixed with posterior-to-anterior lag screws, which provide superior biomechanical pull-out strength compared to anterior-to-posterior screws. This is typically supplemented with a lateral neutralization plate.

Question 45

A 22-year-old male presents with bilateral femoral shaft fractures and a severe closed head injury (GCS 6) following a motor vehicle collision. His initial lactate is 4.5 mmol/L and base deficit is -8. What is the most appropriate initial management of his bilateral femur fractures?

Explanation

This patient is metabolically unstable and has a severe head injury. Under Damage Control Orthopedics (DCO) principles, temporizing external fixation prevents a "second hit" phenomenon and avoids further systemic physiologic burden.

Question 46

A 45-year-old female sustains a highly comminuted fracture of the inferior pole of the patella. The fragments are too small for screw fixation. What is the preferred surgical management to restore the extensor mechanism?

Explanation

For comminuted inferior pole patella fractures unamenable to internal fixation, partial patellectomy with direct reattachment of the patellar tendon via transosseous tunnels or suture anchors is the gold standard.

Question 47

A 30-year-old male with a comminuted tibial shaft fracture complains of increasing pain despite narcotic administration. His blood pressure is 110/65 mmHg. Which of the following intracompartmental pressure measurements is an absolute indication for emergency four-compartment fasciotomy?

Explanation

Acute compartment syndrome is reliably diagnosed when the Delta P (diastolic blood pressure minus the absolute compartment pressure) is less than 30 mmHg. A Delta P of 20 mmHg necessitates an emergent fasciotomy.

Question 48

A 24-year-old athlete sustains a twisting injury to his knee. On physical examination, he demonstrates 15 degrees of increased external tibial rotation compared to the contralateral side at 30 degrees of flexion, but symmetric external rotation at 90 degrees of flexion. What is the most likely injured structure?

Explanation

The Dial test assesses external tibial rotation. Increased rotation at 30 degrees but not at 90 degrees indicates an isolated posterolateral corner (PLC) injury. Combined PCL and PLC injuries show increased rotation at both 30 and 90 degrees.

Question 49

An 80-year-old female with a well-fixed posterior-stabilized total knee arthroplasty sustains a displaced, comminuted distal femur fracture. The femoral component remains stable. What is the most appropriate surgical treatment?

Explanation

For a displaced periprosthetic distal femur fracture with a stable implant, ORIF with a lateral locking plate is the standard of care. A posterior-stabilized box often precludes the use of a retrograde intramedullary nail.

Question 50

A 14-year-old male sustains a type III tibial tubercle avulsion fracture. Several hours after closed reduction, he develops severe pain and paresthesias in the first web space of his foot. Injury to which of the following vessels is most commonly responsible for this specific complication?

Explanation

Tibial tubercle avulsion fractures carry a high risk of anterior compartment syndrome due to laceration or avulsion of the anterior tibial recurrent artery, which traverses directly adjacent to the tubercle.

Question 51

A 28-year-old male sustains a low-velocity gunshot wound to the right knee. Radiographs reveal a retained bullet fragment within the intra-articular space but no fractures. What is the most appropriate management?

Explanation

Retained intra-articular bullets must be surgically removed (arthroscopically or open) due to the severe mechanical third-body wear they cause, as well as the risk of systemic lead toxicity and lead arthropathy.

Question 52

When managing an extra-articular distal femur fracture with a lateral locking plate using bridge plating principles, which of the following mechanical factors most significantly contributes to the risk of hypertrophic nonunion?

Explanation

Hypertrophic nonunion in bridge plating occurs when the construct is overly rigid. Placing screws too close to the fracture site decreases the "working length" and construct compliance, preventing the necessary micromotion for secondary bone healing.

Question 53

A 36-year-old male presents 3 weeks after a motorcycle crash with a large, fluctuant swelling over his greater trochanter. MRI confirms a fluid collection between the subcutaneous fat and the fascia lata. Which of the following is the most appropriate definitive management for this chronic Morel-Lavallée lesion?

Explanation

Chronic Morel-Lavallée lesions develop a fibrous pseudocapsule that prevents fluid resorption. Definitive treatment requires excision of this capsule via open debridement, frequently combined with sclerodesis.

Question 54

A 42-year-old male sustains a Gustilo-Anderson type IIIB open tibial shaft fracture. Following initial aggressive surgical debridement and external fixation, what is the optimal timeframe for definitive soft-tissue flap coverage to maximize limb salvage?

Explanation

The trauma literature demonstrates that definitive soft-tissue flap coverage for Gustilo type IIIB open tibial fractures is optimally performed within 3 to 7 days post-injury to minimize infection and optimize outcomes.

Question 55

A 35-year-old male sustains a bicondylar tibial plateau fracture with a large posteromedial shear fragment. A posteromedial approach is planned for isolated fixation of this fragment. Which of the following defines the correct surgical interval for this approach?

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the pes anserinus tendons anteriorly and the medial head of the gastrocnemius posteriorly. Retracting the gastrocnemius laterally protects the neurovascular bundle.

Question 56

A 25-year-old man presents with a high-energy anterior knee dislocation. He has an absent dorsalis pedis pulse, a pale foot, and a cool extremity. Ischemia time is currently estimated at 6.5 hours. Orthopedic and vascular surgery are both present in the operating room. What is the most appropriate sequence of management?

Explanation

In cases of knee dislocation with prolonged warm ischemia time (greater than 4-6 hours), a temporary vascular shunt should be placed first to restore perfusion. This is followed by rapid skeletal stabilization (external fixation) and then definitive vascular repair and fasciotomies.

Question 57

A 30-year-old female sustains a proximal third tibial shaft fracture and undergoes intramedullary nailing via a standard infrapatellar approach. Postoperatively, she is noted to have a significant apex anterior (procurvatum) deformity. Which of the following technical maneuvers is most effective at preventing this specific deformity during nailing?

Explanation

Proximal tibia fractures are highly prone to procurvatum and valgus deformities when nailed via an infrapatellar approach. Utilizing a semi-extended suprapatellar approach relaxes the extensor mechanism, significantly reducing the risk of apex anterior angulation.

Question 58

A 45-year-old male is undergoing locked plate fixation for a comminuted distal femur fracture (OTA 33-C2). To optimize the biomechanical environment for secondary bone healing, the surgeon wishes to decrease the stiffness of the construct. Which of the following modifications will best achieve this goal?

Explanation

Increasing the working length of the plate by omitting screws in the holes immediately adjacent to the fracture site decreases construct stiffness. This allows for increased micromotion, which promotes secondary bone healing via callus formation.

Question 59

A 22-year-old athlete sustains a displaced coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Open reduction and internal fixation is planned. Which of the following screw configurations provides the most biomechanically stable fixation for this specific fracture pattern?

Explanation

Hoffa fractures (OTA 33-B3) are coronal shear fractures. Biomechanical studies demonstrate that screws placed directed posterior-to-anterior provide superior pullout strength and stability compared to anterior-to-posterior screws.

Question 60

A 14-year-old boy presents with severe anterior knee pain after a jumping injury. Radiographs reveal a displaced avulsion fracture of the tibial tubercle with a fracture line extending into the proximal tibial physis (Ogden Type III). He is admitted for observation after cast immobilization. Which of the following complications is he at highest risk for, and what is the underlying pathoanatomy?

Explanation

Adolescents with Ogden Type III tibial tubercle avulsion fractures are at high risk for acute anterior compartment syndrome. This is due to bleeding from the anterior tibial recurrent artery, which is frequently torn during the avulsion.

Question 61

A 50-year-old polytrauma patient with bilateral femur fractures, multiple rib fractures, and pulmonary contusions arrives in the emergency department. His initial lactate is 4.5 mmol/L, pH is 7.21, and base excess is -8. According to the principles of Damage Control Orthopedics (DCO), what is the most appropriate initial management for his femur fractures?

Explanation

This patient exhibits borderline/unstable physiology (elevated lactate, acidosis, significant base deficit). DCO dictates rapid, minimally invasive stabilization with external fixation to minimize the secondary inflammatory hit, followed by definitive fixation once stabilized.

Question 62

A 29-year-old female presents to the ER with a suspected traumatic knee arthrotomy following a deep laceration just medial to the patella. Radiographs show no fractures. A saline load test is planned. Which of the following statements regarding the saline load test is most accurate?

Explanation

Studies have shown that to achieve a 95% sensitivity in detecting traumatic knee arthrotomies using the saline load test, an average injection volume of 155 mL is required. CT scans are actually more sensitive for detecting intra-articular air than the saline load test.

Question 63

A 38-year-old male sustains a severe closed crush injury to his right thigh. He reports increasing pain out of proportion to the injury. Which of the following parameters is considered the most reliable threshold for diagnosing acute compartment syndrome and indicating the need for immediate fasciotomy?

Explanation

The Delta P value (Diastolic BP - Compartment Pressure) is the most reliable threshold for diagnosing acute compartment syndrome. A Delta P of less than 30 mmHg indicates inadequate capillary perfusion and necessitates emergency fasciotomy.

Question 64

A 65-year-old woman with a history of osteoporosis on long-term alendronate therapy complains of a 3-month history of prodromal lateral left thigh pain. Radiographs reveal localized lateral cortical thickening of the subtrochanteric femur with a transverse radiolucent line, but no complete fracture. What is the most appropriate management?

Explanation

This patient has an incomplete atypical femur fracture (AFF) associated with long-term bisphosphonate use, symptomatic with a radiolucent line. Standard of care includes stopping the bisphosphonate and performing prophylactic intramedullary nailing to prevent complete completion.

Question 65

A 32-year-old man sustains an isolated, closed, transverse midshaft femur fracture. He is hemodynamically stable. The decision is made to perform reamed intramedullary nailing. Which of the following factors has been most strongly associated with the development of Acute Respiratory Distress Syndrome (ARDS) following this procedure?

Explanation

In patients undergoing intramedullary nailing for femur fractures, the strongest predictor for the development of ARDS is the presence of severe concomitant chest trauma (pulmonary contusions). Reaming itself has not been shown to increase ARDS rates compared to unreamed nailing in stable patients.

Question 66

A 24-year-old male sustains a high-energy posterior knee dislocation (KD III). Following successful closed reduction, his foot is warm and pink, and ABIs are >0.9 bilaterally. He undergoes multi-ligament knee reconstruction 3 weeks later. During surgery on the posterolateral corner, the common peroneal nerve is visualized and protected. However, postoperatively he has a new-onset foot drop. What is the most likely cause of this isolated nerve palsy?

Explanation

The common peroneal nerve is tightly tethered at the fibular neck. Indirect traction injuries during posterolateral corner reconstruction or positioning are the most common cause of iatrogenic palsy in this setting, even when the nerve is directly visualized and protected.

Question 67

A 40-year-old male with a BMI of 38 presents with a complete, mid-substance patellar tendon rupture sustained 6 months ago. He has a high-riding patella and a severe extensor lag. Primary end-to-end repair is impossible due to massive retraction. Which of the following is the most appropriate surgical reconstruction option?

Explanation

Chronic patellar tendon ruptures with severe retraction cannot be repaired primarily. Reconstruction using an Achilles tendon allograft with a calcaneal bone block press-fit into the tibial tubercle provides excellent biological fixation and restores extensor mechanism length.

Question 68

A 55-year-old woman undergoes open reduction and internal fixation of a displaced transverse patella fracture using a standard anterior tension band wiring technique. What is the primary biomechanical principle by which this construct provides stable fixation?

Explanation

The anterior tension band wiring principle relies on placing the implant on the tension side (anterior cortex). As the knee flexes, the extensor mechanism exerts a distractive force anteriorly, which the tension band resists and converts into compressive forces at the articular surface.

Question 69

A 26-year-old male sustained a Gustilo IIIB open tibia fracture following a motorcycle accident. He underwent initial thorough debridement and external fixation. According to Godina's classic principles, to minimize the risk of deep infection and flap failure, soft tissue coverage should ideally be performed within what time frame from the initial injury?

Explanation

Godina's landmark study demonstrated that early soft tissue coverage (traditionally within 72 hours) of severe open tibia fractures significantly decreases the rates of deep infection, flap failure, and nonunion compared to delayed coverage.

Question 70

A 21-year-old male sustains a gunshot wound to the anterior knee. Radiographs reveal a retained bullet fragment completely within the intra-articular space of the knee joint. There are no associated fractures, and the neurovascular exam is normal. What is the most appropriate definitive management for the retained bullet?

Explanation

Retained intra-articular bullets exposed to synovial fluid can dissolve and lead to systemic lead toxicity (plumbism) and localized lead arthropathy. They should be surgically removed, typically via arthroscopy if accessible, to prevent these complications.

Question 71

A 33-year-old male is struck by a car and sustains a closed degloving injury over his lateral thigh and greater trochanter, clinically recognized as a Morel-Lavallée lesion. Which of the following best describes the specific pathophysiology of this lesion?

Explanation

A Morel-Lavallée lesion is a closed degloving injury caused by severe shearing forces that separate the skin and subcutaneous tissue from the underlying deep fascia. This tears the trans-fascial perforating vessels, leading to a hemolymphatic fluid collection.

Question 72

A 75-year-old female with an indwelling total knee arthroplasty (TKA) sustains a periprosthetic supracondylar femur fracture (Lewis-Rorabeck Type II). The femoral component remains well-fixed. She is treated with a lateral locking plate. Which of the following technical factors most significantly increases the risk of implant failure and nonunion?

Explanation

In bridge plating of periprosthetic distal femur fractures, leaving an inadequate working length (screws placed too close to the fracture line) makes the construct overly stiff. This concentrates strain at the fracture site, leading to delayed union, nonunion, and ultimate plate breakage.

Question 73

A 28-year-old male sustains an ipsilateral midshaft femur fracture and middle-third tibia fracture (Floating Knee, Fraser Type IIa). He is hemodynamically stable. What is the generally accepted optimal sequence and method of fixation to minimize complications?

Explanation

In a stable patient with a floating knee, definitive fixation is preferred. The standard sequence is intramedullary nailing of the femur first, which stabilizes the limb and facilitates positioning and reduction for subsequent intramedullary nailing of the tibia.

Question 74

A 42-year-old man sustains a highly comminuted Schatzker VI tibial plateau fracture. During surgical approach and reduction, excessive traction is placed on the lateral tissues. Postoperatively, the patient has an inability to extend his great toe and loss of sensation over the first web space. Which specific nerve branch is most likely injured?

Explanation

The deep peroneal nerve innervates the extensor hallucis longus (great toe extension) and provides sensation to the first dorsal web space. It is vulnerable to traction injury or compression during lateral approaches to the proximal tibia.

Question 75

A 35-year-old male sustains a high-energy trauma resulting in an isolated coronal shear fracture of the lateral femoral condyle (Hoffa fracture). Which of the following internal fixation constructs provides the most biomechanically stable fixation?

Explanation

Biomechanical studies have demonstrated that posterior-to-anterior (PA) lag screws provide superior stability and higher load to failure compared to AP screws for Hoffa fractures. This is due to the screw trajectory being more perpendicular to the primary fracture plane.

Question 76

A 45-year-old female undergoes tension band wiring for a transverse patella fracture. According to the principles of tension band fixation, dynamic loading of the knee will convert tensile forces into compressive forces at which of the following locations?

Explanation

The tension band is applied to the anterior surface of the patella to counteract tensile forces. During knee flexion, dynamic loading converts these tensile forces into compressive forces across the posterior articular surface, enhancing fracture stability.

Question 77

A 40-year-old man presents with a Schatzker IV tibial plateau fracture featuring a displaced posteromedial fragment. The surgeon plans an open reduction and internal fixation via a posteromedial approach. Which anatomic interval is classically utilized for this approach?

Explanation

The posteromedial approach to the tibial plateau typically exploits the interval between the medial head of the gastrocnemius (retracted laterally/posteriorly) and the pes anserinus (retracted medially/anteriorly). This allows direct access to buttress posteromedial shear fragments.

Question 78

A 25-year-old male undergoes intramedullary nailing of a closed tibial shaft fracture. Postoperatively, he develops severe leg pain. His blood pressure is 110/70 mmHg. Intracompartmental pressure in the anterior compartment is measured at 45 mmHg. What is the calculated delta pressure and the most appropriate next step?

Explanation

Delta pressure is calculated as Diastolic Blood Pressure minus Intracompartmental Pressure (70 - 45 = 25 mmHg). A delta pressure of 30 mmHg or less is strongly indicative of acute compartment syndrome, necessitating emergent four-compartment fasciotomy.

Question 79

A 60-year-old female is treated with a lateral locking plate for a highly comminuted extra-articular distal femur fracture. To optimize secondary bone healing via callus formation, the surgeon aims to decrease the construct stiffness. Which of the following technical modifications will best achieve this?

Explanation

Increasing the working length (the distance between the two closest screws on either side of the fracture) decreases construct stiffness, allowing appropriate micromotion for secondary bone healing. Filling holes near the fracture makes the construct too stiff, risking hypertrophic nonunion.

OITE & ABOS Orthopedic Exam MCQs: Trauma, Foot & Knee Board Review Part 132

Orthopedic Board Review MCQs: Fracture, Knee & Trauma | Part 77

Key Takeaway

Orthopedic Board Review MCQs: Fracture, Knee & Trauma | Part 77

Chapter Index