Arab Orthopaedic Board MCQs - Part 30

A 5-year-old girl with an untreated late developmental dysplasia of the hip (DDH) undergoes an open reduction. During the procedure, the surgeon performs a femoral shortening osteotomy. What is the primary biomechanical and clinical rationale for incorporating this femoral shortening?

A 45-year-old male sustains a Schatzker IV tibial plateau fracture with a large, displaced posteromedial shear fragment. Which surgical approach provides the most optimal access for direct reduction and anti-glide plating of this specific fragment?

A 25-year-old female presents with a painless, slow-growing mass on the posterior aspect of her distal femur. Radiographs show a dense, ossified mass attached to the cortex by a broad base, with a thin radiolucent cleft between the tumor and the underlying bone (string sign). Histopathology reveals low-grade spindle cells with woven bone. What is the most characteristic genetic alteration associated with this tumor?

A 25-year-old man presents with chronic wrist pain and is diagnosed with a proximal pole scaphoid nonunion. MRI confirms avascular necrosis (AVN) of the proximal pole. Radiographs show no evidence of radiocarpal or midcarpal arthritis (SNAC 0). Which of the following is the most appropriate surgical treatment?

During a reconstruction of the medial patellofemoral ligament (MPFL), the surgeon identifies Schöttle's point using intraoperative fluoroscopy to determine the anatomic femoral footprint. Anatomically, this femoral attachment is located in a saddle-shaped sulcus situated between which two bony landmarks?

A 55-year-old female with a Metal-on-Metal (MoM) total hip arthroplasty presents with new-onset groin pain. Blood tests show elevated cobalt and chromium ions. Which imaging modality is considered the gold standard for diagnosing and assessing the extent of an adverse local tissue reaction (ALTR) or pseudotumor?

A 62-year-old male is evaluated for cervical spondylotic myelopathy. An MRI of the cervical spine is obtained. Which of the following MRI signal characteristics within the spinal cord is most highly predictive of myelomalacia and correlates with poor neurological recovery following decompressive surgery?

A 30-year-old athlete sustains a severe, primarily ligamentous Lisfranc injury. The surgeon plans a classic primary arthrodesis. To optimize functional outcome and gait biomechanics, which tarsometatarsal (TMT) joints should be included in the formal fusion while deliberately sparing the others?

Lubricin (PRG4) is a critical glycoprotein responsible for boundary lubrication in human articular joints. Which cells are the primary producers of lubricin within the joint environment?

During the anterior approach to the pelvis for acetabular fracture fixation, significant hemorrhage can occur due to an anastomotic vessel known as the 'corona mortis'. This structure typically represents a vascular communication between which two systems?

A rugby player sustains a flexor digitorum profundus (FDP) avulsion of the ring finger (Jersey finger). Intraoperatively, the surgeon finds the tendon stump blocked at the level of the A4 pulley due to a large bony avulsion fragment. How is this injury classified according to the Leddy-Packer classification?

Prophylactic in situ pinning of the contralateral, asymptomatic hip in Slipped Capital Femoral Epiphysis (SCFE) is a topic of debate. However, it is almost universally recommended by pediatric orthopedic surgeons in which of the following patient populations?

During a primary cruciate-retaining (CR) total knee arthroplasty, the surgeon evaluates the gaps with trial components. The extension gap is symmetric and perfectly balanced, but the flexion gap is excessively tight. Which of the following is the most appropriate next surgical step to address this imbalance?

A 35-year-old man falls from a height and sustains a T12 burst fracture. He is neurologically intact. MRI demonstrates complete disruption of the posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the recommended management?

A 40-year-old overhead athlete undergoes shoulder arthroscopy. A Partial Articular Supraspinatus Tendon Avulsion (PASTA lesion) is identified. According to established biomechanical and clinical guidelines, surgical repair (either completion and repair or transtendon repair) is generally indicated when the tear involves greater than what percentage of the tendon footprint thickness?

A 65-year-old female with multiple myeloma is evaluated for prophylactic fixation of an impending pathologic fracture. According to Mirels' criteria, which of the following combinations of clinical and radiographic findings yields the highest score, heavily indicating the need for prophylactic internal fixation?

A 55-year-old diabetic patient presents with a profoundly swollen, warm, and erythematous left foot, mimicking cellulitis. Radiographs reveal marked osteopenia, subchondral fragmentation, and periarticular bone debris without overt signs of consolidation. According to the Eichenholtz classification for Charcot neuroarthropathy, what stage does this represent?

A patient suffers a Holstein-Lewis fracture, an oblique/spiral fracture of the distal third of the humerus. In this specific injury pattern, the radial nerve is particularly vulnerable to entrapment or laceration because it is securely tethered as it passes through which anatomic structure?

In orthopedic biomaterials, galvanic corrosion occurs when two electrochemically dissimilar metals are placed in physical contact within a conductive fluid environment (e.g., serum). Which of the following combinations of metals carries the highest risk of severe galvanic corrosion and is therefore contraindicated?

A 2-year-old child is evaluated for multiple fractures with minimal trauma, blue sclerae, and early-onset hearing loss. A diagnosis of Osteogenesis Imperfecta (OI) is suspected. The vast majority of classical OI cases are caused by autosomal dominant mutations affecting type I collagen synthesis. Which genes are most commonly mutated in this condition?