Question 1

Patients sustaining a crushing injury to the foot with midfoot tenderness but without any radiographic signs of fracture or dislocation:

Explanation

Patients who sustain a foot injury and have clinical midfoot tenderness should be assumed to have a serious midfoot sprain until proven otherwise. These patients should be protected non-weight bearing until the tenderness is gone before weight-bearing and physical therapy begins.

Question 2

The calcaneal compartment of the foot contains all of the following structures except:

Explanation

The four interossei muscles are contained in their respective interosseous compartments. The calcaneal compartment may also variably contain the medial plantar nerve. The remaining compartments of the foot are the adductor, medial, lateral, and superficial.

Question 3

Time to radiographic fusion following arthroscopic ankle arthrodesis is:

Explanation

Time to radiographic fusion following arthroscopic ankle arthrodesis is shorter than following open ankle arthrodesis. Theoretically, the decreased dissection and soft-tissue stripping contributes to greater vascular inflow to heal the fusion site.

Question 4

Neighboring joint arthritis following ankle arthrodesis has not been found in the:

Explanation

Long-term follow-up of ankle fusions show that nearly all patients develop arthritis in the hindfoot, midfoot, and 1st metatarsophalangeal joint. There is no evidence to show that the hip or knee is at greater risk for developing arthritis following ankle fusion.

Question 5

Range of motion following total ankle replacement is closely correlated with:

Explanation

A radiographic study comparing preoperative to postoperative tibio-talar range of motion as measured by radiographs showed that the amount of motion that patients had following ankle replacement was most dependent upon the motion they had before surgery.

Question 6

Take-down of ankle arthrodesis and conversion to total ankle replacement:

Explanation

This article studied the success rates of revising previous ankle fusions to ankle replacement. The authors found that if the etiology of a patientâ s pain was unclear, the patients did poorly. Patients with prior fibula resection could still be revised to ankle replacement with allograft bone to support the lateral side of the implant. Range of motion following revision to arthroplasty was comparable to primary replacement.

Question 7

Development of hindfoot arthritis following total ankle replacement is seen in:

Explanation

Although it is felt that the retention of some degree of ankle motion with ankle replacement can help prevent the development of hindfoot arthritis, in a 9-year follow-up study nearly 25% of patients still had radiographic signs of arthritis.

Question 8

Clinical improvement following ankle distraction arthroplasty:

Explanation

Distraction arthroplasty with an Ilizarov external fixator is usually associated with half of the clinical improvement occurring within the first year, and the other half happening over the next 5 years.

Question 9

Isolated subtalar arthrodesis:

Explanation

Subtalar fusion decreased talonavicular motion more so than calcaneocuboid motion in this cadaver study. Isolated talonavicular fusion is the most influential of the hindfoot joints, locking hindfoot motion.

Question 10

Which injury is likely to have a worse clinical outcome:

Explanation

Question 11

C urrently recommended indications for surgical management of hallux rigidus with an arthrodesis include:

Explanation

Coughlin and colleagues recommend that when pain with axial grind testing of the metatarsophalangeal joint is present or >50% loss of articular cartilage occurs intraoperatively, then first metatarsophalangeal arthrodesis should be performed.

Question 12

The main blood supply to the talar body is from the:

Explanation

The main blood supply to the body of the talus is the artery of the tarsal canal, which is a branch off the posterior tibial artery. The dorsalis pedis and the artery of the sinus tarsi supply the talar head.

Question 13

How many weeks following open reduction and internal fixation of a right ankle fracture can patients resume driving with normal braking times:

Explanation

Total braking time following open reduction and internal fixation of right ankle fractures was tested at 6, 9, and 12 weeks postoperatively. These patients were managed with a functional brace, non-weight bearing, and early range of motion in the postoperative period. Braking time was significantly slower than normal at 6 weeks, but had returned to near normal by 9 weeks postoperatively.

Question 14

When using external fixation in the treatment of tibial pilon fractures, distal transfixation wires:

Explanation

In cadaver specimens, the anterolateral capsular reflection of the ankle joint extended proximally the highest with an average of 9.3 mm and a maximum of 12.2 mm. There was a 100% communication between the distal tibia- fibula joint and the ankle joint.

Question 15

Treatment of significant loss of height and posttraumatic arthritis following nonoperative treatment of calcaneus fractures should include:

Explanation

Management of late loss of height following calcaneus fracture is best addressed by a distraction arthrodesis of the subtalar joint using a wedge- shaped structural bone graft.

Question 16

Incisions made through blood-filled fracture blisters have:

Explanation

Biopsies of the edge of fracture blisters following ankle fracture show that blood-filled blisters represent a deeper injury than clear fluid-filled blisters. The dermis of clear blisters still showed some epithelial cells remaining, while the dermis of blood blisters showed no epithelial cells. Therefore, blood-filled blisters are more difficult to heal.

Question 17

Following triple arthrodesis, ankle range of motion is:

Explanation

This clinical study following triple arthrodesis patients for 10 years showed a 27% loss of ankle plantarflexion but no loss of dorsiflexion.

Question 18

A Moberg procedure for hallux rigidus is:

Explanation

The Moberg procedure involves a dorsal closing wedge osteotomy of the proximal phalanx. This sets the hallux higher off the floor, allowing for easier toe-off with less dorsal impingement during gait.

Question 19

The distinguishing factor in a Hawkins type 4 talar neck fracture is:

Explanation

Hawkins type 1 fractures are nondisplaced. Hawkins type 2 fractures have an incongruent subtalar joint. Hawkins type 3 fractures have an incongruent ankle and subtalar joint. Hawkins type 4 fractures have the above injuries and incongruent talo-navicular joint.

Question 20

First metatarsophalangeal prosthetic joint replacements:

Explanation

First metatarsophalangeal joint replacement in this prospective comparative study performed poorly compared to arthrodesis. Patients with arthroplasties had greater pain and little improvement in range of motion.

Question 21

The optimal position for ankle arthrodesis is:

Explanation

The optimal position for ankle arthrodesis is neutral flexion, 5° valgus, and 5Â° external rotation. Historically, surgeons thought that women should be fused in some amount of equinus to better allow them to wear heeled shoes. However, this can increase the development of neighboring joint arthritis and also create a knee recurvatum deformity when ambulating barefoot. Currently it is recommended that all patients are fused in neutral dorsi- /plantarflexion.

Question 22

Isolated talonavicular fusion:

Explanation

This cadaver study examined the motion that remained in the hindfoot joints following sequential immobilization of the talonavicular, subtalar, and calcaneo-cuboid joints. Fixing the talo-navicular joint virtually locked all subtalar motion.

Question 23

The distinction between a Lauge-Hansen supination-external rotation III injury and a Lauge-Hansen supination-external rotation IV injury is:

Explanation

The sequence of injury according to the Lauge-Hansen classification system in supination-external rotation injuries is AITFL disruption, spiral oblique fracture of the lateral malleolus, PITFL disruption or posterior malleolus fracture, and finally stage IV, which is a deltoid ligament disruption or medial malleolus fracture.

Question 24

Isolated subtalar fusion:

Explanation

In 48 subtalar fusions followed for 5 years, 36% of patients developed ankle arthritis and 41% of patients developed transverse tarsal joint arthritis.C orrect Answer: Is associated with the development of both ankle and transverse tarsal joint arthritis

Question 25

The optimal position for hallux interphalangeal joint arthrodesis is:

Explanation

The optimal position for hallux interphalangeal joint arthrodesis is 5° to 10° of plantarflexion, neutral varus-valgus, and neutral rotation. The plantarflexion helps the toe pad to contact the ground during gait.

Question 26

Following anatomic open reduction and internal fixation of a Lisfranc fracture-dislocation:

Explanation

In a series of patients who underwent open reduction internal fixation of Lisfranc fracture dislocations, 25% of patients developed midfoot arthritis at final follow-up, but only half of these patients required eventual midfoot arthrodesis.

Question 27

The maximal joint reactive force in the ankle is approximately:

Explanation

Stauffer and colleagues quantified ankle joint reactive force to be approximately 5 times body weight. This is a significant concern for prosthetic ankle arthroplasty because the implant surface area is relatively small over which these forces must be spread out.

Question 28

Hallux rigidus is associated with:

Explanation

In a large series of patients with hallux rigidus, risk factors were evaluated. The only factor that had a positive correlation with having hallux rigidus was the radiographic shape of the 1st metatarsal head. Metatarsus primus elevatus, first ray hypermobility, or long first metatarsal head were not significantly associated with hallux rigidus.

Question 29

Which nerve is NOT one of the terminal branches of Baxterâ s nerve, also known as the first branch of the lateral plantar nerve:

Explanation

The three terminal branches of Baxterâ s nerve are the nerve to the medial calcaneal periosteum, the nerve to the flexor digitorum brevis, and the nerve to the abductor digiti minimi. The lateral dorsal cutaneous nerve is a branch of the sural nerve.

Question 30

A regimen of ankle bracing and supervised physical therapy:

Explanation

In a study performed by Alvarez and colleagues, 47 patients with stage I or II posterior tibial tendon dysfunction were treated nonoperatively with either a hinged ankle-foot orthosis or foot orthosis and a supervised physical therapy program. After 10 therapy visits, 83% of patients had successful subjective and functional outcomes. Eighty-nine percent of patients were satisfied with the outcome of nonoperative treatment. This included significant improvement in visual analog scale scores and increased strength, concentrically and eccentrically. In this study, 11% of patients failed conservative treatment and required surgery.

Question 31

The use of hyperbaric oxygen (HBO) in the treatment of problematic diabetic foot wounds has been shown to do all of the following except:

Explanation

A meta-analysis of 12 studies showed that healing rates increased from 48% to 76%, and amputation rates decreased from 45% to 19% with the use of hyperbaric oxygen (HBO) and local wound care. In randomized controlled trials, wound area decreased significantly and days to healing decreased significantly in patients treated with HBO. The juxta-wound pO2 was also significantly increased in the HBO-treatment group.

Question 32

The greatest insult to the vascular supply of the first metatarsal head during chevron bunionectomy with lateral release according to intraoperative laser Doppler blood flow measurements was:

Explanation

Twenty patients were prospectively monitored with laser Doppler measurements of metatarsal head blood flow during chevron bunionectomy with lateral release. The greatest loss of blood flow occurred with the medial capsulotomy (45% decrease). The lateral release combined with the adductor tenotomy decreased the blood flow to the metatarsal head by 13%, and the metatarsal osteotomy decreased blood flow by an additional 13%. Total decrease in blood flow to the head was 71%. No patients developed avascular necrosis.

Question 33

In a randomized controlled trial comparing first metatarsophalangeal arthrodesis versus total joint replacement arthroplasty for end-stage hallux rigidus, all of the following statements are true except:

Explanation

In the study by Gibson and Thomson, 38 fusions and 39 arthroplasties were prospectively compared at 2-year follow-up. There was an 82% improvement in the arthrodesis group and only a 45% improvement in the arthroplasty group. Fusion also had lower complication rates and lower cost. There was not a significant increase in first metatarsophalangeal joint dorsiflexion between preoperative and postoperative levels following total joint replacement.

Question 34

The nonunion rate for the Lapidus procedure (first tarsometatarsal arthrodesis) for the treatment of moderate to severe hallux valgus is:

Explanation

In a prospective cohort study following 105 Lapidus bunionectomies for 3.7 years, the nonunion rate was found to be 6.7%. The American Orthopaedic Foot & Ankle Society scores improved significantly, and loss of correction over 3.7 years was less than 1° for intermetatarsal and hallux valgus angles.

Question 35

When using external fixation in the treatment of tibial pilon fractures, distal transfixation wires:

Explanation

In a cadaveric and in vivo study of the reflections of the ankle joint capsule, the distal tibia-fibula joint was found to communicate with the ankle joint capsule, thus representing a risk for ankle sepsis if it is penetrated by a transfixion wire. The anterolateral capsule displayed the most proximal reflection in all specimens.

Question 36

The clinical variable found to be associated with a higher risk of complications following open reduction and internal fixation of unstable ankle fractures in diabetic patients was:

Explanation

A retrospective Level IV study followed 84 patients with diabetes who underwent open reduction internal fixation of unstable ankle fractures. After analyzing multiple patient factors including sex, fracture pattern, open or closed injury, nephropathy, hypertension, vasculopathy, peripheral neuropathy, and diabetic control (insulin-dependent compared with non- insulindependent), the only factors that predicted a higher rate of complications were vasculopathy and peripheral neuropathy. There was a 12% rate of postoperative infection and an overall 14% rate of complications.

Question 37

Which modality for the treatment of chronic insertional Achilles tendinopathy was shown to have the best clinical outcome:

Explanation

A randomized controlled trial compared recalcitrant insertional Achilles tendinopathy treated with eccentric heel cord stretching versus low-energy shockwave therapy. At 4 months, 28% of the stretching group and 64% of the shockwave therapy group reported complete relief of symptoms or greatly improved symptoms. All outcome measures showed favorable results with shockwave therapy.

Question 38

Urgent closed reduction of ankle fracture-dislocations using intraarticular lidocaine injection:

Explanation

A prospective randomized study compared intraarticular lidocaine injection to conscious sedation for analgesia during reduction of ankle fracture- dislocations. There was no difference in the amount of analgesia provided by the two methods. Time for reduction and splinting was less in the local anesthetic group. Quality of reduction was similar in both groups.

Question 39

A tailorâ s bunion is an abnormal prominence of the lateral aspect of the 5th metatarsal head. Similar to hallux valgus deformities, tailorâ s bunions can be due to a widened intermetatarsal angle between the 4th and 5th metatarsal shafts. The normal 4-5 intermetatarsal angle is:

Explanation

4-5 intermetarsal angle in normal feet averages 6.2 degrees. Different authors believe an abnormally wide 4-5 intermetatarsal angle to be anything greater than 8°-9°.

Question 40

A 54-year-old woman with a 10-year history of type II diabetes mellitus develops a Wagner grade 2 ulceration under the first metatarsal head, which has not healed for 3 months. There is no gross cellulitis or drainage. A tagged white blood cell scan shows no signs of osteomyelitis, and noninvasive vascular studies reveal normal hemodynamics. She has failed wet-to-dry normal saline dressings and bacitracin ointment local wound care. The next step in treating this patientâ s chronic ulcer is:

Explanation

The description of the ulcer indicates that it is not grossly infected and that there is no underlying bony involvement. According to evidence based medicine, the only treatments that are likely to be effective in the healing of diabetic foot ulcerations are topical growth factors, total contact casting, and for severely infected ulcers hyperbaric oxygen.

Question 41

Which is the best match in surface topography when performing an osteochondral autograft transplantation procedure from the distal femur to the talar dome for an osteochondral lesion of the talus:

Explanation

In a magnetic resonance imaging topography study looking for the best corresponding shape of the articular surface between the non-weightbearing femoral condyle and the medial talar dome, plugs from the supero-lateral femoral condyle had the best fit with osteochondral lesions of the medial talus in the anterior, central, and posterior zones.

Question 42

The most frequent location for osteochondral lesions of the talar dome is:

Explanation

A survey of 428 osteochondral lesions of the talus was undertaken using a nine zone anatomical grid system to determine the most frequent location in which these lesions occur. Results showed that 62% of lesions occurred in the medial talar dome and 34% over the lateral talar dome. The most frequent location along the medial dome was the mid-body of the talus. Medial lesions were larger in surface area as well as deeper than lateral lesions.

Question 43

Which gait parameters are significantly improved following first metatarsophalangeal arthrodesis for symptomatic hallux rigidus:

Explanation

A prospective gait study was performed measuring various gait parameters 1 week prior to and 1 year following first metatarsophalangeal joint arthrodesis. The three significant changes in gait were increased maximal ankle push off power, increased single limb support time on the affected limb, and decreased step width. Stride length, walking velocity, and cadence were not significantly different after fusion.

Question 44

Which clinical or radiographic finding is not commonly associated with moderate or severe hallux valgus deformity in adults:

Explanation

A clinical series of 122 bunions was evaluated for demographic, etiologic, and radiographic findings associated with moderate to severe hallux valgus deformity. The following findings were reported: 83% of patients had a positive family history of bunions 84% of patients had bilateral bunion deformities 71% of patients had curved or oval-shaped metatarsophalangeal joints 71% of patients had a longer 1st metatarsal compared to the 2nd metatarsal by an average of 2.4 mm 11% of bunions were associated with an Achilles tendon contracture

Question 45

A 58-year-old runner has symptoms of chronic noninsertional Achilles tendinopathy for 8 months. Rest, ice, anti-inflammatory medications, and heel wedges have not helped. Which of the following treatments may help alleviate this patientâ s symptoms:

Explanation

Noninsertional Achilles tendinosis is a noninflammatory degenerative condition that is common in middle-aged athletes. In a 3- year follow-up study examining the use of topical glyceryl trinitrate for Achilles tendinosis, patients were noted to have significantly less tendon tenderness and improved clinical scores compared to the placebo group. At 3 years, 88% of treated patients were asymptomatic. Novel nonoperative measures include sclerosing injections into the Achilles tendon with polidocanol and shock- wave therapy to the Achilles tendon.

Question 46

When comparing complication rates following operative and nonoperative management of ankle fractures in the elderly (age 65- 99):

Explanation

A study using the National Medicare C laims History System was performed looking at outcomes following ankle fracture in 33,704 elderly patients, specifically looking at mortality, rehospitalization, and the need for additional surgery. Researchers found that conservatively managed patients had a higher mortality rate up to 2 years following injury compared to patients who underwent open reduction internal fixation. Operatively treated patients had a higher rate of rehospitalization following their injury. Less than 1% of patients required revision of internal fixation, arthroplasty, arthrodesis, or amputation.

Question 47

Exposure of tendons to ciprofloxacin in vitro causes all of the following except:

Explanation

Ciprofloxacin was shown to cause a decrease in fibroblast proliferation, proteoglycan synthesis, and collagen synthesis. Matrix degrading proteolytic activity was increased.

Question 48

The Brostrom lateral ligament reconstruction is a reliable technique for primary stabilization of ankle instability. The Gould modification of this technique uses which structure to reinforce the repair:

Explanation

The initial description of the Gould modification of the Brostrom procedure recommended â suturing what one finds (there is always some ligament present) and reinforcing the anterior talofibular ligament repair with overlap of the nearby lateral talocalcaneal ligament plus the marginal ankle retinaculumâ .

Question 49

Following ankle injury, which radiographic parameter is indicative of syndesmotic instability:

Explanation

The normal radiographic findings of the syndesmosis on plain radiographs of the ankle are: Medial clear space less than or equal to 4 mm Syndesmotic clear space less than 5 mm measured 1 cm above the ankle joint on the AP view of the ankle Syndesmotic overlap greater than 1 mm measured 1 cm above the ankle joint on the mortise view of the ankle

Question 50

In children between ages 7 and 11 with bilateral flexible flatfeet and without any pathologic findings, the use of custom-made orthotics or off-the-shelf orthotics demonstrate:

Explanation

In a randomized controlled trial comparing children with flatfeet treated with custom orthotics, off-the-shelf orthotics, and no treatment, there were no differences in the above parameters found. The study concluded that no significant difference was found with regard to motor proficiency, pain, exercise efficiency, or self-perception.

Question 51

In a vertical shear pelvic ring injury, which muscle group is primarily responsible for the cephalad migration of the unstable hemipelvis?

Explanation

The quadratus lumborum and the lateral abdominal wall musculature attach to the iliac crest. In a vertically unstable pelvic fracture, these muscles contract and draw the hemipelvis cranially.

Question 52

A 24-year-old athlete undergoes an open Latarjet procedure for recurrent anterior shoulder instability with significant glenoid bone loss. Which nerve is most at direct risk during the coracoid transfer and inferior subscapularis split?

Explanation

The musculocutaneous nerve enters the coracobrachialis 5 to 8 cm distal to the coracoid process. It is at significant risk during coracoid osteotomy, mobilization, and retraction during the Latarjet procedure.

Question 53

A 12-year-old boy presents with an acute on chronic slipped capital femoral epiphysis (SCFE) and is entirely unable to bear weight. Following in situ pinning, what is the most significant risk factor for the development of avascular necrosis (AVN) of the femoral head?

Explanation

An unstable SCFE is defined by the inability to bear weight even with crutches. Unstable slips have a significantly higher rate of avascular necrosis (up to 50%) compared to stable slips.

Question 54

Following a total hip arthroplasty utilizing a posterior approach, a patient is noted to have a sciatic nerve palsy. Which component of the sciatic nerve is most commonly injured, and what is the characteristic motor deficit?

Explanation

The peroneal division of the sciatic nerve is tethered at the fibular head and has less supportive connective tissue, making it more susceptible to stretch injuries during hip surgery. Injury results in foot drop (loss of dorsiflexion).

Question 55

A 28-year-old male sustains a proximal pole scaphoid fracture. The high risk of nonunion and avascular necrosis in this region is due to its retrograde blood supply primarily derived from which vessel?

Explanation

The primary blood supply to the scaphoid enters distally via the dorsal carpal branch of the radial artery. This retrograde flow makes proximal pole fractures highly susceptible to avascular necrosis.

Question 56

A 65-year-old patient with long-standing rheumatoid arthritis presents with progressive myelopathy. Flexion-extension radiographs reveal 9 mm of anterior atlantoaxial subluxation without cranial settling. What is the most appropriate surgical management?

Explanation

For anterior atlantoaxial subluxation with myelopathy but without cranial settling or subaxial involvement, a C1-C2 posterior fusion is indicated. Occipitocervical fusion is reserved for cases with cranial settling.

Question 57

During the remodeling phase of fracture healing, woven bone is replaced by lamellar bone. Which type of collagen is the predominant organic component of the extracellular matrix in mature lamellar bone?

Explanation

Type I collagen makes up roughly 90% of the organic matrix of mature bone. It provides tensile strength and serves as the primary scaffolding for mineralization.

Question 58

A 15-year-old girl undergoes neoadjuvant chemotherapy and subsequent wide resection for a conventional high-grade distal femur osteosarcoma. Which of the following is the most significant prognostic factor for her overall survival?

Explanation

The histologic response to neoadjuvant chemotherapy, specifically having greater than 90% tumor necrosis, is the single most important prognostic indicator for overall survival in conventional osteosarcoma.

Question 59

In a purely ligamentous Lisfranc injury, which anatomical structure is considered the primary stabilizer of the second tarsometatarsal joint?

Explanation

The Lisfranc ligament is an interosseous ligament connecting the medial cuneiform to the base of the second metatarsal. It is the strongest and most critical primary stabilizer of the tarsometatarsal complex.

Question 60

A 45-year-old sustains a high-energy Schatzker type IV (medial) tibial plateau fracture. Which surgical approach is most frequently indicated to directly buttress the primary fracture fragment?

Explanation

Schatzker IV fractures involve the medial plateau and often have a posteromedial shear component. A posteromedial approach allows for direct visualization and anti-glide buttress plating of the posteromedial fragment.

Question 61

A 6-month-old infant with developmental dysplasia of the hip (DDH) fails initial treatment with a Pavlik harness after 4 weeks. What is the next most appropriate step in management?

Explanation

If a Pavlik harness fails to achieve reduction after 3 to 4 weeks in an infant, it should be discontinued to prevent "Pavlik harness disease" (posterior acetabular wear). The next step is a closed reduction and spica casting under anesthesia.

Question 62

A 22-year-old soccer player undergoes anterior cruciate ligament (ACL) reconstruction utilizing a bone-patellar tendon-bone (BTB) autograft. What is the most commonly reported complication specifically associated with this graft choice compared to hamstring autograft?

Explanation

Anterior knee pain, including pain with kneeling, is the most frequently cited complication following BTB autograft. Patellar fracture is a known but rare complication.

Question 63

During a total knee arthroplasty, internally rotating the femoral component relative to the epicondylar axis will most likely result in which of the following mechanical issues?

Explanation

Internal rotation of the femoral component medializes the trochlear groove, effectively increasing the Q-angle dynamically. This leads to lateral patellar tracking, tilt, and potential lateral subluxation.

Question 64

Which of the following rehabilitation principles is most universally recommended over absolute immobilization following a Zone II flexor tendon repair to optimize outcomes and prevent adhesions?

Explanation

Early active or controlled passive motion (e.g., modified Duran or Kleinert protocols) enhances intrinsic tendon healing and prevents restrictive adhesion formation. Immobilization leads to poor functional results.

Question 65

A 40-year-old male presents with right leg pain radiating to the dorsum of the foot and weakness in great toe extension following a paracentral disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

Explanation

A paracentral disc herniation in the lumbar spine typically compresses the traversing nerve root. At the L4-L5 level, the L5 nerve root is compressed, leading to weakness in extensor hallucis longus (EHL) and altered sensation on the foot's dorsum.

Question 66

A 28-year-old male has an atrophic midshaft femoral nonunion 9 months after initial statically locked intramedullary nailing. Infection has been ruled out. What is the most appropriate surgical intervention?

Explanation

Exchange nailing with reaming to a larger diameter is the gold standard for aseptic diaphyseal nonunions. It provides both enhanced mechanical stability and a biologic stimulus (reaming debris) for healing.

Question 67

Tranexamic acid (TXA) is now routinely used to reduce blood loss in total joint arthroplasty. What is its primary biochemical mechanism of action?

Explanation

Tranexamic acid is a synthetic analog of the amino acid lysine. It competitively inhibits the activation of plasminogen to plasmin, thereby preventing the degradation of fibrin clots (antifibrinolytic effect).

Question 68

A 14-year-old boy presents with a destructive diaphyseal lesion in the femur with a permeative pattern and an "onion skin" periosteal reaction. Cytogenetic testing reveals a specific chromosomal translocation. Which translocation is most characteristic of this tumor?

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. Over 90% of Ewing sarcomas are characterized by the t(11;22)(q24;q12) translocation, resulting in the EWS-FLI1 fusion protein.

Question 69

Compared to operative management of acute Achilles tendon ruptures, recent level I evidence regarding non-operative management utilizing early functional rehabilitation demonstrates:

Explanation

Recent trials utilizing early functional rehabilitation show similar re-rupture rates and functional outcomes between operative and non-operative management. However, non-operative management avoids the wound healing complications and infection risks associated with surgery.

Question 70

A 24-year-old athlete sustains a plantar flexion injury to the midfoot. Weight-bearing radiographs show a 2mm diastasis between the base of the first and second metatarsals. What is the primary stabilizing ligament disrupted in this injury?

Explanation

The Lisfranc ligament is an interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the second metatarsal base. It is the primary stabilizer of the second tarsometatarsal joint.

Question 71

In the treatment of a displaced vertical femoral neck fracture (Pauwels type III) in a 30-year-old patient, which internal fixation construct provides the most biomechanical stability against shear forces?

Explanation

A sliding hip screw (DHS) with an anti-rotation screw provides superior biomechanical stability against the high shear forces seen in vertical (Pauwels III) femoral neck fractures compared to multiple parallel cancellous screws.

Question 72

A 45-year-old male presents with acute onset saddle anesthesia, bilateral sciatica, and bowel incontinence following a heavy lifting event. Which of the following is the most consistent early urodynamic finding in this condition?

Explanation

Cauda equina syndrome typically causes a lower motor neuron lesion of the bladder, leading to detrusor areflexia and urinary retention. This manifests clinically as overflow incontinence and an increased post-void residual volume.

Question 73

A 65-year-old female presents with persistent groin pain 1 year after an uncemented total hip arthroplasty. Radiographs reveal a radiolucent line involving all three DeLee and Charnley zones of the acetabulum with superior migration of the cup. What is the most appropriate management?

Explanation

Circumferential radiolucent lines in all three DeLee and Charnley zones coupled with component migration indicate definitive aseptic loosening of the acetabular cup. The standard treatment is revision arthroplasty of the failed component.

Question 74

During surgical repair of a Zone II flexor digitorum profundus (FDP) laceration, which of the following pulleys is most critical to preserve or reconstruct to prevent bowstringing of the tendon?

Explanation

The A2 and A4 pulleys arise from the proximal and middle phalanges, respectively, and are the most mechanically important pulleys. Preserving or reconstructing them is critical to prevent bowstringing and ensure proper flexor tendon kinematics.

Question 75

A 12-year-old obese male presents with left groin pain and an obligatory external rotation of the hip during passive flexion. Which of the following is an absolute indication for open reduction and internal fixation of this condition rather than in-situ pinning?

Explanation

In-situ pinning remains the gold standard for both stable and unstable Slipped Capital Femoral Epiphysis (SCFE) to minimize the risk of osteonecrosis. Open reduction (e.g., modified Dunn procedure) is controversial and not considered an absolute indication.

Question 76

Which of the following blood vessels provides the primary vascular supply to the watershed area of the Achilles tendon (2 to 6 cm proximal to its insertion)?

Explanation

The Achilles tendon receives its blood supply primarily from the posterior tibial and peroneal arteries. The peroneal artery provides the main vascularization to the critical watershed area 2-6 cm proximal to the calcaneal insertion.

Question 77

Which of the following prognostic factors is considered the most significant predictor of overall survival in a patient with localized osteosarcoma of the distal femur treated with neoadjuvant chemotherapy and wide resection?

Explanation

The degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for overall survival in patients with localized osteosarcoma. Greater than 90% necrosis indicates a favorable response.

Question 78

A 25-year-old athlete undergoes an anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft. Improper placement of the femoral tunnel too anteriorly will result in which of the following kinematic abnormalities?

Explanation

An anteriorly placed femoral tunnel causes the ACL graft to be loose in extension and excessively tight in flexion. This improper placement leads to a loss of full knee flexion and predisposes the graft to stretching or failure.

Question 79

In an anteroposterior compression type III (APC-III) pelvic ring injury, which of the following ligamentous structures is completely disrupted, distinguishing it from an APC-II injury?

Explanation

An APC-II injury involves disruption of the symphysis, anterior SI, sacrospinous, and sacrotuberous ligaments but leaves the posterior SI ligaments intact. An APC-III injury includes complete disruption of the posterior SI ligaments, causing complete global pelvic instability.

Question 80

Which type of collagen is predominantly synthesized by chondrocytes during the soft callus phase of secondary fracture healing?

Explanation

During the soft callus phase of secondary fracture healing, endochondral ossification occurs where chondrocytes primarily synthesize Type II collagen. As the callus calcifies, hypertrophic chondrocytes express Type X collagen before bone (Type I) is deposited.

Question 81

During a primary total knee arthroplasty, the surgeon notices that the knee is tight in flexion but stable and balanced in extension. Which of the following surgical adjustments should be made to correct this gap imbalance?

Explanation

A knee that is tight in flexion but balanced in extension indicates an isolated tight flexion gap. This is typically addressed by downsizing the femoral component, which decreases the anteroposterior dimension of the femur.

Question 82

A 60-year-old male presents with deteriorating fine motor skills in his hands, a broad-based gait, and hyperreflexia. Which radiographic measurement on a lateral cervical spine X-ray strongly correlates with an increased risk of cervical spondylotic myelopathy?

Explanation

The Torg-Pavlov ratio compares the AP diameter of the spinal canal to the AP diameter of the vertebral body. A ratio of less than 0.8 indicates congenital cervical stenosis and a substantially higher risk for developing cervical myelopathy.

Question 83

A 55-year-old female presents with a painful, flexible flatfoot deformity. She is unable to perform a single-leg heel rise. MRI confirms a complete rupture of the posterior tibial tendon. What is the most appropriate surgical intervention?

Explanation

For a Stage II (flexible) adult-acquired flatfoot deformity due to posterior tibial tendon insufficiency, joint-sparing surgery is indicated. FDL transfer combined with a medial displacement calcaneal osteotomy addresses both the tendon pathology and the mechanical malalignment.

Question 84

According to the Gustilo-Anderson classification, an open tibial shaft fracture with a 12 cm laceration, extensive soft tissue stripping, but adequate periosteal coverage of the bone fragment is classified as:

Explanation

A Type IIIA open fracture involves extensive soft tissue damage (usually a wound >10 cm) but maintains adequate soft tissue or periosteal coverage of the fractured bone, thereby not requiring a free tissue transfer or rotational flap.

Question 85

In the Ponseti method for the treatment of idiopathic clubfoot, what is the final component of the deformity to be corrected before proceeding with an Achilles tenotomy?

Explanation

The Ponseti method addresses deformities in a specific sequence: Cavus, Adductus, Varus, and finally Equinus (CAVE). A percutaneous Achilles tenotomy is frequently performed at the end to correct residual equinus contracture.

Question 86

Which zone of the meniscus has the highest healing potential following repair, and what is its primary blood supply?

Explanation

The peripheral third (red-red zone) of the meniscus is highly vascularized and has excellent healing potential. It receives its blood supply from a perimeniscal capillary plexus originating from the medial and lateral genicular arteries.

Question 87

Which of the following local anesthetics has the longest duration of action and blocks neural transmission by binding to the intracellular portion of voltage-gated sodium channels?

Explanation

Bupivacaine is an amide local anesthetic notable for its high protein binding, conferring a long duration of action. Like all local anesthetics, it crosses the neural membrane and blocks voltage-gated sodium channels from the inside.

Question 88

A patient with severe carpal tunnel syndrome exhibits profound thenar atrophy. Which specific muscle, innervated by the recurrent motor branch of the median nerve, is primarily responsible for the bulk of the thenar eminence affected in this condition?

Explanation

The thenar eminence bulk is primarily composed of the opponens pollicis and abductor pollicis brevis. Severe median nerve compression causes denervation via the recurrent motor branch, leading to visible atrophy of these muscles.

Question 89

When evaluating a patient for acute compartment syndrome of the lower leg, which measurement parameter is considered the most reliable threshold for indicating an emergent fasciotomy?

Explanation

The delta pressure, defined as the diastolic blood pressure minus the intracompartmental pressure, is the most accurate diagnostic parameter for compartment syndrome. A delta pressure of less than 30 mmHg strongly indicates the need for fasciotomy.

Question 90

A 24-year-old athlete sustains a hyperplantarflexion injury to the midfoot. Weight-bearing radiographs demonstrate a 2.5 mm diastasis between the base of the first and second metatarsals. What is the primary stabilizing structure of this articulation?

Explanation

The Lisfranc ligament is an interosseous plantar ligament connecting the lateral aspect of the medial cuneiform to the medial aspect of the second metatarsal base. It is the primary stabilizer of the second tarsometatarsal joint; there is no direct ligamentous connection between the first and second metatarsal bases.

Question 91

A 45-year-old male presents with a severely displaced intra-articular distal tibia (pilon) fracture with significant soft tissue swelling and fracture blisters. What is the most appropriate initial management to minimize soft tissue complications while awaiting definitive fixation?

Explanation

High-energy pilon fractures with severe soft tissue compromise are best managed initially with a spanning external fixator and elevation. Definitive open reduction and internal fixation is typically delayed until the wrinkle sign appears, indicating reduced soft tissue swelling.

Question 92

A 13-year-old obese boy undergoes in-situ percutaneous pinning for a stable slipped capital femoral epiphysis (SCFE). He presents 6 months later with worsening hip stiffness and pain. Radiographs demonstrate joint space narrowing and subchondral cyst formation but no avascular necrosis. What is the most likely diagnosis?

Explanation

Chondrolysis is a known complication of SCFE, characterized by progressive loss of articular cartilage and joint stiffness. It is associated with unrecognized intra-articular pin penetration, though it can occur idiopathically in the setting of the disease itself.

Question 93

A 32-year-old female sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) with severe angulation and >5 mm of translation (Levine-Edwards Type IIA). What is the mechanism of this specific fracture pattern and the appropriate initial management?

Explanation

A Type IIA Hangman's fracture occurs via a flexion-distraction mechanism, resulting in severe angulation with minimal initial translation that becomes highly unstable with traction. Skeletal traction is absolutely contraindicated as it exacerbates the deformity; management involves gentle reduction in slight extension and compression in a halo vest.

Question 94

A 65-year-old male presents with groin pain and an enlarging soft tissue mass 5 years after a primary total hip arthroplasty utilizing a metal-on-polyethylene bearing with a large diameter modular metal head. Aspiration yields sterile, cloudy fluid. MRI demonstrates an adverse local tissue reaction (ALTR). What is the most likely etiology?

Explanation

Trunnionosis, or mechanically assisted crevice corrosion at the head-neck junction, can lead to adverse local tissue reactions (ALTR) even with metal-on-polyethylene bearings. Risk factors include the use of large diameter modular metal heads, which increase the torque and micromotion at the trunnion.

Question 95

During a physical examination of a patient with a suspected multiligament knee injury, the dial test is performed. The test shows 15 degrees of increased external rotation at 30 degrees of knee flexion compared to the contralateral side, but symmetric external rotation at 90 degrees of flexion. Which structure is most likely injured?

Explanation

The dial test measures external rotation of the tibia. Increased external rotation at 30 degrees but not at 90 degrees indicates an isolated posterolateral corner (PLC) injury. If increased external rotation is present at both 30 and 90 degrees, a combined PLC and posterior cruciate ligament (PCL) injury is suspected.

Question 96

A 16-year-old male is diagnosed with osteosarcoma of the distal femur. Genetic analysis of the tumor reveals a mutation in a tumor suppressor gene heavily implicated in cell cycle regulation at the G1/S checkpoint. Patients with a germline mutation in this gene have a high incidence of bilateral retinoblastoma. Which gene is this?

Explanation

The RB1 gene is a tumor suppressor gene that regulates the cell cycle at the G1/S checkpoint. Germline mutations result in hereditary retinoblastoma and significantly increase the lifetime risk of developing secondary primary malignancies, most notably osteosarcoma.

Question 97

A 22-year-old male falls on an outstretched hand and sustains a proximal pole scaphoid fracture. Which of the following best describes the vascular supply to the proximal pole of the scaphoid and the implication for this fracture?

Explanation

The primary vascular supply to the scaphoid is retrograde via branches of the radial artery entering the dorsal ridge distally. This tenuous retrograde blood flow places proximal pole fractures at a significantly higher risk for avascular necrosis and nonunion.

Question 98

A 55-year-old female presents with progressive flattening of her left foot and medial arch pain. On examination, she has a flexible flatfoot deformity and cannot perform a single-limb heel rise. Radiographs show no degenerative changes in the subtalar or talonavicular joints. What is the correct stage of her posterior tibial tendon dysfunction (PTTD) and the most appropriate surgical management if conservative treatment fails?

Explanation

Stage II PTTD is characterized by a flexible planovalgus deformity, inability to perform a single heel rise, and absent degenerative joint changes. Surgical management typically involves joint-sparing procedures such as an FDL tendon transfer coupled with a medial displacement calcaneal osteotomy.

Question 99

A 40-year-old male sustains an Anteroposterior Compression (APC) Type III pelvic ring injury after a motorcycle crash. Anteroposterior pelvic radiographs reveal a pubic symphysis diastasis of 3.5 cm and widening of the sacroiliac joints bilaterally. Which of the following ligamentous structures is completely disrupted in this specific injury pattern?

Explanation

APC Type III injuries involve complete symphyseal diastasis with complete disruption of both the anterior and posterior sacroiliac ligaments, as well as the sacrotuberous and sacrospinous ligaments. This extensive ligamentous failure results in complete global instability of the hemipelvis.

Orthopedic Prometric Exam Preparation MCQs - Part 1

Orthopedic Prometric Exam Preparation MCQs - Part 7

Orthopedic Prometric Exam Preparation MCQs - Part 7

Chapter Index