Orthopedic Board MCQs: Deformity, Elbow, Hip & Shoulder

Question 1

A 35-year-old male presents with recurrent clicking and apprehension when pushing up from a chair 6 months after an elbow dislocation. Which ligament is primarily deficient, and what is the typical path of subluxation?

Explanation

Posterolateral rotatory instability (PLRI) is caused by a deficiency of the lateral ulnar collateral ligament (LUCL). During provocative maneuvers (like pushing off a chair), the radius and ulna supinate and subluxate posterolaterally away from the humerus as a single unit.

Question 2

In a 4-year-old child with developmental dysplasia of the hip, an osteotomy is planned to improve anterolateral acetabular coverage. The osteotomy is described as an incomplete pericapsular cut that hinges on the triradiate cartilage without extending into the sciatic notch. Which osteotomy is being described?

Explanation

The Pemberton osteotomy is an incomplete pericapsular osteotomy that cuts through the ilium down to, and hinging on, the flexible triradiate cartilage. This allows the acetabular roof to be hinged downward to improve anterolateral coverage. A Salter osteotomy is a complete transiliac cut that hinges on the pubic symphysis.

Question 3

A 22-year-old rugby player presents with recurrent anterior shoulder instability. A 3D CT scan demonstrates 25% anterior glenoid bone loss and an engaging Hill-Sachs lesion. What is the most appropriate surgical management?

Explanation

For critical anterior glenoid bone loss (generally >20-25%) in a high-demand collision athlete, an arthroscopic or open Bankart repair has an unacceptably high failure rate. A coracoid transfer (Latarjet) is indicated to restore the glenoid arc and provide the dynamic 'sling' effect of the conjoint tendon.

Question 4

A 2.5-year-old obese girl presents with bilateral genu varum. Radiographs show a metaphyseal-diaphyseal angle (Drennan's angle) of 18 degrees and medial physeal beaking. What is the most appropriate initial management?

Explanation

The patient has infantile Blount's disease (Langenskiöld stage I/II), indicated by her age, obesity, metaphyseal-diaphyseal angle > 16 degrees, and physeal beaking. In a child under 3 years old, conservative management with daytime bracing (KAFO) is the standard initial treatment. Surgery is reserved for older children or failure of bracing.

Question 5

During surgical reconstruction of a 'terrible triad' injury of the elbow, what is the standard recommended sequence of repair to progressively restore stability?

Explanation

The standard sequence for terrible triad repair is deep to superficial, anterior to posterior. The coronoid is addressed first (via suture lasso, screw, or plate), followed by radial head fixation or arthroplasty, and finally LCL repair to the lateral epicondyle.

Question 6

A 13-year-old boy presents with severe left hip pain and inability to bear weight following a minor fall. Radiographs confirm a severe, unstable slipped capital femoral epiphysis (SCFE). A modified Dunn procedure is considered. What vascular structure is most at risk and must be meticulously protected during the surgical dislocation and callus debridement?

Explanation

The deep branch of the medial femoral circumflex artery (MFCA) is the primary blood supply to the femoral head. In the modified Dunn procedure (capital realignment via surgical hip dislocation) for severe unstable SCFE, the retinacular vessels branching from the MFCA must be meticulously preserved as they run along the posterosuperior femoral neck to prevent avascular necrosis (AVN).

Question 7

What is the primary biomechanical advantage of a reverse total shoulder arthroplasty (RTSA) in the setting of rotator cuff tear arthropathy?

Explanation

According to Grammont's principles, a reverse shoulder arthroplasty medializes and distalizes the center of rotation of the glenohumeral joint. This increases the moment arm of the deltoid, recruits more deltoid muscle fibers, and increases resting tension, allowing the deltoid to effectively elevate the arm in the absence of a functional rotator cuff.

Question 8

When performing distraction osteogenesis for a post-traumatic tibial bone defect using an Ilizarov frame, what are the classic optimal latency period and rate of distraction to promote high-quality regenerate bone?

Explanation

Ilizarov established the biologic principles for distraction osteogenesis. The optimal latency period is typically 5 to 7 days to allow the initial phase of fracture healing (callus formation) before distraction begins. The ideal rate is 1.0 mm per day (usually divided into 4 increments of 0.25 mm) to optimize regenerate bone formation without causing premature consolidation or nonunion.

Question 9

A 38-year-old female presents with chronic groin pain exacerbated by hip flexion and internal rotation. An AP pelvis radiograph reveals a 'crossover sign.' What underlying pathomorphology does this indicate, and what type of impingement is most likely?

Explanation

The 'crossover sign' is visible on an AP pelvis radiograph when the anterior wall of the acetabulum crosses lateral to the posterior wall. This indicates cranial acetabular retroversion, leading to anterior overcoverage of the femoral head. It is a classic radiographic hallmark of Pincer-type femoroacetabular impingement (FAI).

Question 10

A 42-year-old female sustains an elbow injury. Radiographs reveal a type IV Bryan and Morrey capitellum fracture. What is the defining characteristic of this fracture pattern?

Explanation

In the Bryan and Morrey classification of capitellar fractures: Type I (Hahn-Steinthal) is a large osseous segment. Type II (Kocher-Lorenz) is an articular cartilage shell. Type III is comminuted. Type IV (McKee modification) is a coronal shear fracture that involves both the capitellum and a significant portion of the trochlea.

Question 11

A 45-year-old laborer has an irreparable posterosuperior rotator cuff tear with an intact subscapularis, severe external rotation lag, and a positive hornblower's sign. There is no glenohumeral arthritis. Which tendon transfer is most biomechanically appropriate to restore external rotation?

Explanation

For an irreparable posterosuperior cuff tear with profound external rotation weakness (hornblower's sign indicates teres minor deficiency) and an intact subscapularis, restoring external rotation is paramount. The lower trapezius tendon transfer, often augmented with an Achilles tendon allograft, most closely replicates the force vector of the infraspinatus. Latissimus dorsi is also an option but historically has variable outcomes for pure ER restoration compared to lower trapezius.

Question 12

A 9-year-old boy presents with a cubitus varus deformity 3 years after a supracondylar humerus fracture. He is asymptomatic, but if left uncorrected, what is the most significant potential late functional complication of this deformity?

Explanation

While initially a cosmetic issue, the mechanical axis deviation in cubitus varus causes the triceps to pull in a medially displaced vector. Over years, this repetitive eccentric loading stretches the lateral ulnar collateral ligament (LUCL) complex, eventually predisposing the patient to tardy posterolateral rotatory instability (PLRI) and ulnar neuropathy. Tardy ulnar nerve palsy is classically associated with cubitus valgus.

Question 13

A 65-year-old male presents with groin pain and a palpable mass 5 years after receiving a metal-on-polyethylene total hip arthroplasty using a large-diameter cobalt-chromium femoral head. Serum metal ions show significantly elevated cobalt and normal chromium levels. What is the most likely diagnosis?

Explanation

Elevated cobalt out of proportion to chromium in a patient with a metal-on-polyethylene bearing indicates mechanically assisted crevice corrosion (trunnionosis) at the modular head-neck junction. Metal-on-metal bearing wear typically produces elevated levels of both cobalt and chromium. Large diameter metal heads increase the torsional forces at the trunnion, predisposing to this complication, known as adverse local tissue reaction (ALTR) or ALVAL.

Question 14

During anatomic reconstruction of a chronic type V acromioclavicular (AC) joint separation, the surgeon reconstructs the coracoclavicular (CC) ligaments. To accurately reproduce the biomechanics of the native joint, where should the conoid and trapezoid reconstruction tunnels be placed relative to the distal clavicle?

Explanation

The trapezoid ligament is positioned more anteriorly and laterally, inserting approximately 2.5 cm (25 mm) medial to the distal clavicle. The conoid ligament is positioned more posteromedially, inserting on the conoid tubercle approximately 4.5 cm (45 mm) medial to the distal clavicle.

Question 15

A 38-year-old bodybuilder undergoes distal biceps tendon repair using a single anterior incision technique. Postoperatively, he exhibits weakness in extending the wrist and fingers, though wrist drop is incomplete. The affected nerve most likely runs between which two muscle bellies near the level of the radial neck?

Explanation

The posterior interosseous nerve (PIN) is at risk during a single-incision distal biceps repair, particularly with aggressive lateral retraction. The PIN enters the arcade of Frohse and travels through the supinator muscle, specifically between its superficial and deep heads.

Question 16

A newborn is noted to have a fully segmented hemivertebra at T8, causing congenital scoliosis. Ultrasound of the renal system and an echocardiogram are both normal. What is the most critical next diagnostic screening study required for this patient prior to any surgical planning?

Explanation

Congenital scoliosis has a high association with VACTERL anomalies and intraspinal anomalies (such as tethered cord, diastematomyelia, syringomyelia). Approximately 20-40% of patients with congenital scoliosis have an associated intraspinal anomaly, mandating an MRI of the entire neuroaxis to rule out these conditions before any surgical intervention or bracing.

Question 17

A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic findings is recognized as one of Catterall's 'head-at-risk' signs, indicating a poorer prognosis?

Explanation

Catterall's 'head-at-risk' signs for poor prognosis in Perthes disease include: Gage's sign (a V-shaped radiolucency in the lateral portion of the epiphysis/metaphysis), lateral subluxation of the femoral head, calcification lateral to the epiphysis, diffuse metaphyseal reaction, and a horizontal growth plate.

Question 18

In evaluating a proximal humerus fracture for the risk of avascular necrosis (AVN), which of the following is considered the strongest predictor of ischemia to the articular segment according to Hertel's criteria?

Explanation

Hertel described radiographic predictors of ischemia in proximal humerus fractures. The strongest predictors include a short posteromedial metaphyseal head extension (<8 mm) attached to the articular segment, disruption of the medial hinge (>2 mm), and an anatomic neck fracture pattern. These indicate disruption of the arcuate artery, the terminal branch of the anterior humeral circumflex artery.

Question 19

In the pathogenesis of Charcot neuroarthropathy, the neurovascular theory suggests that autonomic neuropathy leads to which of the following physiologic changes?

Explanation

The neurovascular theory of Charcot arthropathy postulates that autonomic neuropathy results in a loss of sympathetic control, leading to localized hyperemia and arteriovenous shunting. This hyperemia causes increased osteoclastic activity, active bone resorption, and subsequent osteopenia, making the bones highly susceptible to fracture and collapse with normal weight-bearing.

Question 20

A 4-month-old infant with developmental dysplasia of the hip is being treated with a Pavlik harness. During a follow-up visit, the infant is noted to lack active knee extension on the treated side, though there is normal ankle movement. What is the most appropriate next step in management?

Explanation

A lack of active knee extension in an infant treated with a Pavlik harness indicates a femoral nerve palsy, a known complication caused by hyperflexion. The initial and most appropriate treatment is to completely remove the harness to allow the nerve to recover. Continuing the harness, even with adjustments, risks further permanent nerve damage or complete failure of the harness treatment (Pavlik disease).

Question 21

A 72-year-old female undergoes a reverse total shoulder arthroplasty (rTSA) for severe rotator cuff tear arthropathy. Which of the following best describes the fundamental biomechanical alteration achieved by the rTSA implant design compared to native anatomy?

Explanation

The reverse total shoulder arthroplasty (rTSA) inherently medializes and distalizes the center of rotation of the glenohumeral joint. Medialization increases the number of deltoid fibers recruited for elevation, while distalization tensions the deltoid, increasing its moment arm. This allows the deltoid to effectively compensate for the deficient rotator cuff.

Question 22

A 55-year-old male complains of a loud 'squeaking' noise coming from his hip 3 years after a ceramic-on-ceramic total hip arthroplasty. He is otherwise asymptomatic. Radiographs show a well-fixed implant. Which of the following is the most likely primary etiology of this phenomenon?

Explanation

Squeaking in ceramic-on-ceramic THA is heavily associated with edge loading, which typically occurs due to component malposition (e.g., increased acetabular anteversion/inclination or loss of femoral offset). Edge loading leads to stripe wear on the ceramic head, altering fluid film lubrication and generating the audible squeak. It is generally not caused by galvanic corrosion or cement debris.

Question 23

A 34-year-old male falls on an outstretched arm and sustains an elbow injury. Examination reveals varus posteromedial rotatory instability (VPMRI). Which of the following injury patterns is most classically associated with this specific physical examination finding?

Explanation

Varus posteromedial rotatory instability (VPMRI) is caused by an axial load combined with a varus force. It classically presents with a fracture of the anteromedial facet of the coronoid and an associated avulsion or tear of the lateral collateral ligament (LCL) complex. This contrasts with posterolateral rotatory instability (PLRI) which involves radial head/coronoid tip fractures (terrible triad).

Question 24

According to the principles of deformity correction formulated by Paley, what is the expected outcome if an osteotomy is performed at a level separate from the Center of Rotation of Angulation (CORA), but the correction axis (hinge) is placed exactly on the CORA?

Explanation

According to Paley's Rule 2: When the osteotomy is made at a level separate from the CORA, but the hinge (axis of correction) is placed on the CORA, the correction will result in both angulation and translation at the osteotomy site. However, the mechanical/anatomical axes of the proximal and distal segments will become collinear. Paley's Rule 1 states that if both the osteotomy and hinge are at the CORA, pure angulation occurs.

Question 25

A 22-year-old rugby player undergoes an open Latarjet procedure for recurrent anterior shoulder instability with 30% glenoid bone loss. Postoperatively, he exhibits profound weakness in elbow flexion and decreased sensation over the lateral forearm. Which of the following structures was most likely injured during the surgical approach?

Explanation

The musculocutaneous nerve is the most frequently injured nerve during the Latarjet procedure due to its proximity to the coracoid process and the conjoint tendon (which is mobilized and transferred). It pierces the coracobrachialis muscle on average 5-8 cm distal to the coracoid tip. Injury leads to biceps/brachialis weakness and numbness over the lateral cutaneous nerve of the forearm.

Question 26

In the pathophysiology of Cam-type femoroacetabular impingement (FAI), which of the following best describes the primary mechanism of chondral injury?

Explanation

Cam FAI is characterized by an aspherical femoral head (decreased head-neck offset) that forces its way into the acetabulum during flexion. This generates significant shear forces at the anterosuperior acetabulum, tearing the labrum from the transitional cartilage and causing an 'inside-out' delamination of the articular cartilage. Contrecoup lesions are typically seen in Pincer impingement.

Question 27

A 45-year-old mechanic presents with insidious onset of weakness in finger and thumb extension, without sensory deficits. Compression of the posterior interosseous nerve (PIN) is suspected. Which of the following represents the most common site of compression for this nerve?

Explanation

The Arcade of Frohse is a fibrous band at the proximal edge of the superficial head of the supinator muscle and is the most common site of compression for the posterior interosseous nerve (PIN). PIN compression presents with motor weakness of the wrist and finger extensors (often sparing the ECRL, leading to radial deviation on wrist extension) without sensory deficits.

Question 28

Which of the following radiographic parameters is considered the most reliable predictor of humeral head ischemia following a proximal humerus fracture, according to Hertel's criteria?

Explanation

Hertel et al. described the geometric predictors of humeral head ischemia. The combination of an intact medial hinge (>2 mm displacement indicates disruption) and a short metaphyseal head extension (calcar length <8 mm) attached to the articular segment are the most powerful predictors of ischemia, carrying a positive predictive value of 97% for AVN.

Question 29

A 60-year-old male with a metal-on-polyethylene total hip arthroplasty presents with new-onset groin pain and a pseudotumor on MRI. Infection workup is negative. Blood metal ion levels reveal elevated serum cobalt relative to chromium. This clinical picture is most likely driven by mechanically assisted crevice corrosion (MACC) at which interface?

Explanation

Adverse Local Tissue Reaction (ALTR) in the setting of a metal-on-polyethylene THA is typically caused by trunnionosis. This is mechanically assisted crevice corrosion (MACC) occurring at the modular junction between the metallic femoral head and the femoral neck trunnion. It typically causes higher serum cobalt levels compared to chromium.

Question 30

A 14-year-old elite gymnast presents with lateral elbow pain and catching. Radiographs reveal a radiolucent lesion in the capitellum. The pathogenesis of this condition is most directly related to which of the following?

Explanation

Osteochondritis dissecans (OCD) of the capitellum is predominantly seen in adolescent throwing athletes and gymnasts. It is caused by repetitive valgus compression and shear forces at the radiocapitellar joint. The capitellum is particularly vulnerable due to its tenuous, end-arterial blood supply.

Question 31

A newborn is diagnosed with Congenital Femoral Deficiency (CFD). During the comprehensive orthopedic evaluation, the surgeon must actively screen for commonly associated anomalies. Which of the following conditions is LEAST likely to be associated with CFD?

Explanation

Congenital Femoral Deficiency (CFD), formerly known as PFFD, belongs to the 'lateral ray' developmental field defect. It is highly associated with fibular hemimelia, ACL deficiency, coxa vara, and patellar instability. Tibial hemimelia is a 'medial ray' deficiency and is generally not associated with CFD.

Question 32

During a coracoclavicular (CC) ligament reconstruction for a high-grade acromioclavicular joint separation, the surgeon passes grafts to recreate the native ligaments. Which of the following accurately describes the anatomic relationship of the native CC ligaments?

Explanation

The coracoclavicular (CC) ligaments consist of the conoid and trapezoid. The conoid ligament is located medial and posterior (inserting on the conoid tubercle of the clavicle), and it acts as the primary restraint to superior/inferior translation. The trapezoid ligament is lateral and anterior (inserting on the trapezoid line), acting as the primary restraint to axial compression.

Question 33

A 75-year-old female who underwent revision total hip arthroplasty with a dual mobility construct presents with an acute dislocation. Radiographs reveal the 'bubble sign' with eccentric position of the femoral head within the acetabular shell. What is the precise mechanism of this specific type of intraprosthetic dislocation?

Explanation

Intraprosthetic dislocation (IPD) is a unique complication of dual mobility cups. It occurs when the polyethylene retentive rim wears out or fails, allowing the smaller, inner metallic/ceramic femoral head to 'escape' the large mobile polyethylene head. The small head then articulates directly with the metallic acetabular shell, creating the eccentric 'bubble sign' on radiographs.

Question 34

A 30-year-old female falls on an outstretched hand and sustains a capitellar fracture. On CT scan, the fracture fragment consists of a large, hemispherical piece of articular cartilage with minimal to no attached subchondral bone. This morphology is best classified as which type of capitellar fracture?

Explanation

Bryan and Morrey Classification of capitellar fractures: Type I (Hahn-Steinthal) involves a large osseous component. Type II (Kocher-Lorenz) is a shear fracture involving articular cartilage with minimal attached subchondral bone (the 'uncapped' appearance). Type III (Broberg-Morrey) is highly comminuted. Type IV (McKee) extends medially to include the lateral trochlear ridge.

Question 35

A 4-year-old boy with Proximal Focal Femoral Deficiency (PFFD) is evaluated for a Van Nes rotationplasty. For this procedure to be functionally successful, which of the following anatomic prerequisites is absolutely essential?

Explanation

In a Van Nes rotationplasty, the limb is rotated 180 degrees so that the ankle joint functions as the new knee joint for the prosthetic fitting. Therefore, a fully functional, mobile, and stable ankle joint with active motor control is a strict prerequisite for the procedure's functional success.

Question 36

A 28-year-old patient presents with symptomatic scapular winging following a posterior triangle lymph node biopsy. On examination, the scapula rests in a translated lateral and downwardly rotated position. The winging is accentuated when the patient abducts the arm against resistance. Which nerve is most likely injured?

Explanation

Spinal accessory nerve (CN XI) injury leads to trapezius palsy, causing 'lateral winging' (scapula is displaced laterally and downwardly rotated). This is often an iatrogenic complication of posterior cervical triangle biopsy. Lateral winging is accentuated by resisted shoulder abduction. In contrast, long thoracic nerve injury (serratus anterior palsy) causes 'medial winging' which is worsened by forward elevation/wall push-ups.

Question 37

In the management of Legg-Calve-Perthes disease, the Herring Lateral Pillar Classification is widely used due to its strong prognostic value. Which radiographic feature specifically defines a Herring Group B classification?

Explanation

The Herring Lateral Pillar classification evaluates the height of the lateral third of the femoral head on an AP pelvis radiograph during the fragmentation stage. Group A: No involvement of the lateral pillar. Group B: >50% of lateral pillar height is maintained. Group C: <50% of lateral pillar height is maintained. Group B/C border refers to exactly 50% height.

Question 38

A 65-year-old female with severe rheumatoid arthritis is considering a semiconstrained (linked) Total Elbow Arthroplasty (TEA). When discussing the long-term prognosis and risks, what should the surgeon quote as the most common long-term complication leading to revision?

Explanation

Aseptic loosening remains the most common long-term complication and the most frequent reason for revision of a total elbow arthroplasty, especially in linked (semiconstrained) designs, due to the high biomechanical stresses transferred to the bone-cement interface at the bushing hinges.

Question 39

A 2-year-old obese child presents with bilateral genu varum. You are distinguishing between physiologic bowing and infantile Blount disease. On standing AP radiographs, measurement of the metaphyseal-diaphyseal angle (MDA) of Drennan is performed. An angle greater than what threshold is highly predictive of progression to infantile Blount disease?

Explanation

Drennan's metaphyseal-diaphyseal angle (MDA) is used to differentiate physiologic bowing from infantile Blount disease. An angle > 16 degrees represents a high probability of progression to Blount disease. An angle < 10 degrees is typical of physiologic bowing, while 10-16 degrees is an indeterminate 'gray zone' requiring close observation.

Question 40

When using a hexapod external fixator (e.g., Taylor Spatial Frame) for complex lower extremity deformity correction, what represents its primary biomechanical and functional advantage over a traditional Ilizarov circular frame?

Explanation

The primary advantage of hexapod systems (utilizing the Stewart-Gough platform concept) is the ability to correct complex deformities in all six degrees of freedom simultaneously. It uses a computer-generated 'virtual hinge', allowing continuous multiplanar correction by simply adjusting strut lengths daily, whereas a traditional Ilizarov frame requires physical dismantling and remounting of hinges/constructs to correct multiple planes or sequential translation/angulation.

Question 41

A 45-year-old male sustains a terrible triad injury of the elbow following a fall. Intraoperatively, the surgeon decides on a single lateral approach. What is the recommended sequence of anatomical repair to systematically restore elbow stability?

Explanation

Standard management of terrible triad injuries proceeds from deep to superficial. The coronoid (and anterior capsule) is repaired first, followed by the radial head (repair or arthroplasty), and finally the lateral ulnar collateral ligament.

Question 42

A 28-year-old female presents with deep groin pain exacerbated by hip flexion and internal rotation. An AP pelvis radiograph demonstrates a 'cross-over sign'. What type of femoroacetabular impingement and anatomical abnormality does this represent?

Explanation

The 'cross-over sign' occurs when the anterior wall of the acetabulum projects lateral to the posterior wall on an AP radiograph. This indicates cranial or focal acetabular retroversion, which leads to pincer-type impingement.

Question 43

A 72-year-old female undergoes a reverse total shoulder arthroplasty for cuff tear arthropathy. How does the biomechanical design of the prosthesis primarily improve active elevation?

Explanation

A reverse total shoulder arthroplasty shifts the center of rotation medially and inferiorly. This change recruits more deltoid muscle fibers and significantly increases its moment arm, compensating for the absent rotator cuff.

Question 44

In deformity correction planning using the principles of Paley, a closing wedge osteotomy is performed on the tibia. If the osteotomy hinge is placed outside the center of rotation of angulation (CORA), what is the expected geometric consequence?

Explanation

According to the CORA principles, if an osteotomy hinge is placed at the CORA, pure angulation occurs. If the hinge is placed outside the CORA, correcting the angulation will obligatorily induce translation of the bone segments.

Question 45

A 30-year-old male sustains an Essex-Lopresti injury. During surgery, the highly comminuted radial head is excised and not replaced. What is the most likely biomechanical complication of this omission?

Explanation

An Essex-Lopresti injury involves a longitudinal radioulnar dissociation with interosseous membrane disruption. Excision of the radial head removes the primary proximal stabilizer, leading to severe proximal radial migration and ulnocarpal impaction syndrome.

Question 46

A 6-week-old infant is treated with a Pavlik harness for developmental dysplasia of the hip. At the first follow-up, the parents report the infant is no longer kicking the affected leg. Examination reveals decreased active knee extension but normal foot movements. What is the most appropriate next step?

Explanation

Decreased active knee extension indicates a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The anterior strap must be loosened to decrease hip flexion and relieve tension on the femoral nerve.

Question 47

A 25-year-old baseball pitcher complains of vague posterior shoulder pain and weakness in external rotation. Examination shows isolated atrophy of the infraspinatus with normal supraspinatus bulk. A paralabral cyst is suspected. Where is the cyst most likely located?

Explanation

Compression of the suprascapular nerve at the spinoglenoid notch affects only the motor branch to the infraspinatus. Compression at the suprascapular notch would affect both the supraspinatus and infraspinatus.

Question 48

In the Ponseti method for the treatment of idiopathic clubfoot, what is the correct sequence of deformity correction?

Explanation

The Ponseti method follows the CAVE mnemonic: Cavus (corrected by elevating the first ray), Adduction, Varus, and finally Equinus. Correcting the equinus last typically requires a percutaneous Achilles tenotomy.

Question 49

A 22-year-old collegiate baseball pitcher presents with posterior elbow pain during the deceleration phase of throwing. He lacks 15 degrees of full extension. Radiographs show posteromedial olecranon osteophytes. What is the primary underlying pathomechanical cause?

Explanation

Valgus extension overload syndrome is primarily caused by chronic insufficiency of the anterior band of the UCL. This permits excessive valgus opening during throwing, leading to reactive osteophyte formation and impingement in the posteromedial olecranon fossa.

Question 50

A 6-year-old boy is diagnosed with Legg-Calve-Perthes disease. Which of the following radiographic findings represents one of Catterall's 'head-at-risk' signs, indicating a poorer prognosis?

Explanation

Catterall's 'head-at-risk' signs include Gage sign (a V-shaped radiolucency in the lateral epiphysis/metaphysis), lateral calcification, lateral subluxation, a horizontal physis, and metaphyseal cysts.

Question 51

During an arthroscopic anterior Bankart repair on a right shoulder, the surgeon places a suture anchor at the 5:30 position on the glenoid rim. Which major anatomical structure is primarily tensioned by shifting the labrum superiorly at this position?

Explanation

The anterior band of the inferior glenohumeral ligament (IGHL) typically attaches to the glenoid at the 5 to 6 o'clock position (in a right shoulder). Tensioning this structure is critical to restoring anterior stability.

Question 52

Which of the following is the most common musculoskeletal manifestation requiring surgical intervention in adult patients with achondroplasia?

Explanation

Adults with achondroplasia frequently require surgery for symptomatic lumbar spinal stenosis. This is caused by congenitally short pedicles, thickened lamina, and a narrowing interpedicular distance in the lower lumbar spine.

Question 53

A 45-year-old male undergoes a single-incision anterior repair of a distal biceps tendon rupture. Postoperatively, he is unable to actively extend his fingers or thumb, but wrist extension is partially preserved with a radial deviation bias. Which nerve was injured during the approach?

Explanation

The posterior interosseous nerve (PIN) is at risk during single-incision anterior distal biceps repairs, especially with vigorous radial retraction. PIN injury causes finger/thumb extension loss, but radial wrist extension remains via the ECRL (innervated by the radial nerve proper).

Question 54

In reverse total shoulder arthroplasty (RTSA), inferior tilt and inferior overhang of the glenosphere are primarily designed to prevent which of the following complications?

Explanation

Scapular notching is a common complication of RTSA caused by mechanical impingement of the humeral component against the scapular neck. Inferior tilt and overhang of the glenosphere laterally clear the implant from the bone, significantly reducing this risk.

Question 55

A 12-year-old obese male undergoes in-situ pinning for a slipped capital femoral epiphysis (SCFE). Intraoperatively, the slip is noted to be unstable as the patient could not bear weight prior to surgery. Compared to a stable SCFE, this patient is at significantly higher risk for which complication?

Explanation

Unstable SCFE, defined by the inability to bear weight even with crutches, carries a markedly higher risk of avascular necrosis (AVN) compared to stable SCFE. This is due to disruption or kinking of the retinacular vessels.

Question 56

During surgical management of a terrible triad injury of the elbow, the radial head is fixed and the lateral ulnar collateral ligament (LUCL) is repaired. The coronoid fracture involves the anteromedial facet. What is the most appropriate management of this coronoid fracture?

Explanation

Anteromedial facet fractures of the coronoid provide critical varus and posteromedial rotatory stability to the elbow. They must be rigidly fixed (e.g., suture lasso, screws, or plate) to restore joint congruity and stability.

Question 57

In deformity correction principles, if an opening wedge osteotomy is performed at a level distant to the Center of Rotation of Angulation (CORA) but the mechanical axes are subsequently realigned, what is the expected geometric result at the osteotomy site?

Explanation

According to Paley's rules of deformity, performing an osteotomy at a level different from the CORA and realigning the mechanical axis will inherently result in translation of the bone segments.

Question 58

A 25-year-old male presents with a locked posterior shoulder dislocation. Which of the following mechanisms of injury is most classically associated with a traumatic posterior dislocation?

Explanation

Traumatic posterior shoulder dislocations classically occur from axial loading on an adducted, flexed, and internally rotated arm. Seizures and electrocution are other common causes due to powerful internal rotator muscle contraction.

Question 59

A 30-year-old male presents with activity-related groin pain. Pelvic radiographs reveal a crossover sign, a prominent ischial spine sign, and a posterior wall sign. Which anatomic abnormality is primarily responsible for his femoroacetabular impingement?

Explanation

The crossover sign, ischial spine sign, and posterior wall sign are classic radiographic hallmarks of acetabular retroversion, which leads to focal anterior pincer-type impingement.

Question 60

A 28-year-old weightlifter undergoes repair of an acute distal biceps rupture via a single-incision anterior approach. Postoperatively, he reports numbness over the radial aspect of his forearm. Which nerve is most likely injured?

Explanation

The LABC nerve is the most commonly injured nerve during a single-incision anterior distal biceps repair due to lateral retraction. The PIN is classically at risk during a two-incision approach if the forearm is not fully supinated during the deep dissection.

Question 61

A patient is undergoing deformity correction for a midshaft tibial malunion. According to Paley's rules of osteotomies, if the osteotomy is performed at a site separate from the Center of Rotation of Angulation (CORA) and the proximal and distal mechanical axes are aligned, what is the inevitable geometric result?

Explanation

According to Osteotomy Rule 2, when the osteotomy is performed outside the CORA and the axes are realigned, the bone ends will translate (displace) at the osteotomy site. This translation must be accommodated to restore the mechanical axis.

Question 62

A 40-year-old female presents with posterolateral rotatory instability (PLRI) of the elbow. During the lateral pivot-shift test of the elbow, at what degree of flexion does maximal subluxation of the radial head typically occur?

Explanation

In PLRI, the lateral ulnar collateral ligament (LUCL) is deficient. During the pivot-shift test, the radial head maximally subluxates posteriorly at approximately 40 to 50 degrees of flexion before reducing as flexion increases.

Question 63

A 24-year-old female with developmental dysplasia of the hip undergoes a Bernese periacetabular osteotomy (PAO). Through the standard Smith-Petersen approach, which osteotomy is typically performed first and requires fluoroscopy to ensure it is incomplete and does not enter the joint?

Explanation

The incomplete ischial osteotomy is typically the first bone cut in a Bernese PAO. It is performed just distal to the acetabulum, leaving the posterior column intact, and requires fluoroscopy to avoid intra-articular penetration.

Question 64

A 65-year-old male presents with an irreparable subscapularis tear and recurrent anterior shoulder instability. The posterosuperior rotator cuff is intact. Which tendon transfer is most biomechanically appropriate to restore anterior shoulder stability and internal rotation?

Explanation

The pectoralis major transfer (either split or entire tendon) is the preferred procedure for irreparable subscapularis tears. It best replicates the vector of the subscapularis to provide anterior stability and internal rotation.

Question 65

During an open release for severe post-traumatic elbow stiffness via a lateral column approach, the anterior capsule is excised, which improves flexion. However, extension remains severely limited. What is the most appropriate next step in the surgical sequence?

Explanation

When elbow extension remains limited after anterior capsular release, the next step is to address the posterior impingement. This involves excising the posterior capsule and frequently resecting the tip of the olecranon.

Question 66

In an 8-year-old boy undergoing guided growth for genu valgum with a tension band plate (8-plate) on the medial distal femur, how does this implant alter the physis compared to traditional rigid Blount staples?

Explanation

The tension band plate functions as a flexible hinge. The screws are not locked to the plate, allowing them to diverge as the bone grows, which reduces the risk of hardware failure and permanent physeal arrest seen with rigid staples.

Question 67

A 13-year-old obese boy requires in-situ pinning for a stable slipped capital femoral epiphysis (SCFE). To minimize the risk of joint penetration while maximizing mechanical stability, the single screw should be placed in which zone of the femoral head?

Explanation

In SCFE pinning, the goal is to place a single screw in the center of the epiphysis (central-central position) perpendicular to the physis. This provides optimal stability and minimizes the risk of unrecognized intra-articular screw penetration.

Question 68

A 30-year-old male is undergoing reconstruction of a Type V acromioclavicular (AC) joint separation using a free tendon graft. To accurately recreate the native anatomy of the coracoclavicular ligaments, where should the conoid and trapezoid insertions be targeted relative to the distal clavicle?

Explanation

The conoid ligament inserts more medially (approximately 45 mm from the distal clavicle), whereas the trapezoid inserts more laterally (approximately 25 mm from the distal clavicle). Restoring this footprint optimizes the biomechanics of the AC joint.

Question 69

During a two-incision distal biceps tendon repair, the surgeon develops the posterior plane between the supinator and the extensor carpi radialis brevis. Which nerve is at greatest risk of injury during this posterior exposure if the forearm is not fully pronated?

Explanation

The posterior interosseous nerve (PIN) lies within the supinator muscle. Maximally pronating the forearm moves the PIN anteriorly and medially, protecting it during the posterolateral approach of a two-incision distal biceps repair.

Question 70

When utilizing a Taylor Spatial Frame to correct a complex multiplanar deformity, the surgeon must input specific parameters into the software. The "mounting parameters" specifically refer to which of the following?

Explanation

Mounting parameters describe the exact position of the reference ring in relation to the origin (the reference point on the bone, usually the CORA). This includes AP, lateral, and axial translation and angulation offsets.

Question 71

A 6-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs reveal that exactly 60% of the lateral pillar height is maintained. According to the Herring lateral pillar classification, what is his group and the most appropriate standard initial management?

Explanation

Maintenance of >50% lateral pillar height defines Herring Group B. In a patient under the age of 8, Group B disease is typically treated non-operatively with observation, activity modification, and maintaining range of motion.

Question 72

A 72-year-old female receives a reverse total shoulder arthroplasty for a 4-part proximal humerus fracture. The surgeon performs a tuberosity repair. Healing of the greater tuberosity is considered most critical for restoring which specific shoulder function?

Explanation

The greater tuberosity serves as the attachment for the infraspinatus and teres minor. Healing of the greater tuberosity to the shaft in a reverse total shoulder arthroplasty is essential to restore active external rotation.

Question 73

In the surgical treatment of a terrible triad injury of the elbow, the coronoid is fixed, the radial head is replaced, and the lateral collateral ligament (LCL) is repaired. However, the elbow remains subluxated and unstable in extension. What is the most appropriate next step?

Explanation

The standard surgical algorithm for a terrible triad injury proceeds from deep to superficial and lateral to medial. If the elbow remains unstable after coronoid, radial head, and LCL repair, the next step is to repair the MCL.

Question 74

A 28-year-old male undergoes arthroscopic osteochondroplasty for femoroacetabular impingement (FAI) due to a large CAM lesion. Over-resection of the anterolateral femoral head-neck junction places the patient at greatest risk for which devastating complication?

Explanation

Resecting more than 30% of the anterolateral femoral neck diameter significantly alters the biomechanics and dramatically increases the risk of a postoperative iatrogenic femoral neck fracture.

Question 75

A 24-year-old elite baseball pitcher presents with posterior shoulder pain during the late cocking phase. MRI reveals a partial articular-sided supraspinatus tendon avulsion (PASTA) and a superior labrum anterior-posterior (SLAP) tear. This specific triad of "internal impingement" is most strongly associated with which clinical finding?

Explanation

Internal impingement in overhead throwing athletes (PASTA lesion, SLAP tear, posterior shoulder pain) is biomechanically driven by a tight posterior capsule, which clinically presents as Glenohumeral Internal Rotation Deficit (GIRD).

Question 76

A 3-year-old child presents with bilateral tibia vara. Standing AP radiographs reveal a metaphyseal-diaphyseal angle (Drennan angle) of 18 degrees on both sides. What is the most appropriate initial management for this patient?

Explanation

A Drennan angle >16 degrees indicates a high likelihood of true infantile Blount's disease rather than physiologic bowing. For a child under 4 years old, the initial standard of care is bracing with KAFOs.

Question 77

A 15-year-old female gymnast is diagnosed with a capitellar osteochondritis dissecans (OCD) lesion. MRI shows the articular cartilage is intact. Which radiographic view best profiles the capitellum to monitor lesion size and healing during non-operative management?

Explanation

The capitellum is situated anteriorly on the distal humerus. The AP axial view (taken with the elbow flexed 45 degrees) best profiles the articular surface of the capitellum, clearly demonstrating OCD lesions.

Question 78

During a revision total hip arthroplasty, the surgeon encounters a Paprosky Type IIIB acetabular defect. There is complete loss of the medial wall, superior migration of 3.5 cm, and severe ischial lysis. Which reconstructive option provides the most reliable mechanical fixation for this specific defect pattern?

Explanation

Paprosky Type IIIB defects involve severe pelvic discontinuity or highly compromised inferior bone (ischium) with >3 cm up-migration. Standard cups or jumbo cups have high failure rates here; cup-cage constructs or custom triflange implants are required to span the defect.

Orthopedic Surgery Board Review MCQs: Arthroplasty, Ligament & Spine | Part 149

Orthopedic Board Review MCQs: Deformity, Elbow, Hip & Shoulder | Part 143

Key Takeaway

Orthopedic Board Review MCQs: Deformity, Elbow, Hip & Shoulder | Part 143

Chapter Index