Orthopedic Review | Dr Hutaif General Orthopedics Revie -...

A 4-month-old infant presents with recurrent fractures, cranial nerve palsies, and diffuse skeletal sclerosis on radiographs. Genetic testing reveals a mutation in the TCIRG1 gene. Which of the following is the primary pathophysiologic mechanism responsible for this condition?

A 25-year-old male presents following a high-speed MVC with a closed midshaft femur fracture, bilateral pulmonary contusions, and a GCS of 7. His arterial blood gas reveals a pH of 7.21, lactate of 4.5 mmol/L, and PaO2/FiO2 ratio of 180. Which of the following is the most appropriate initial management of his femur fracture?

A 65-year-old male presents with groin pain 5 years after undergoing an uncomplicated primary total hip arthroplasty utilizing a large diameter CoCr head on a titanium stem. Radiographs show a well-fixed stem and cup with no osteolysis. Laboratory tests show elevated serum cobalt levels, normal ESR, and normal CRP. Joint aspiration yields opaque fluid with negative cultures. What is the most likely diagnosis?

A 13-year-old obese boy presents with 3 weeks of insidious onset left groin and thigh pain. He walks with a limp and exhibits an externally rotated foot progression angle. On examination, as the left hip is flexed, it obligately externally rotates. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). Which of the following represents the primary mechanism of displacement?

During an electrodiagnostic study, a patient's median nerve is stimulated at the elbow and wrist, recording over the abductor pollicis brevis, showing normal amplitude. However, when recording over the first dorsal interosseous (FDI), stimulating the median nerve at the elbow produces a compound muscle action potential (CMAP), but stimulating it at the wrist does not. Which anatomical variant explains this finding?

A 15-year-old male presents with persistent distal thigh pain. Radiographs reveal a poorly defined, mixed lytic and sclerotic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms high-grade intramedullary osteosarcoma. Which of the following genetic alterations is most frequently associated with the pathogenesis of this tumor?

A 28-year-old male sustains a dashboard injury in a motor vehicle collision. Examination reveals a positive posterior drawer test. The dial test shows a 15-degree increase in external rotation at both 30 degrees and 90 degrees of flexion compared to the contralateral normal knee. Which of the following structures are most likely injured?

A 55-year-old poorly controlled diabetic male presents with a swollen, warm, and erythematous right foot. He denies any systemic symptoms. Radiographs show fragmentation of the navicular and cuneiforms with early subluxation at the midtarsal joints. Which of the following is the most appropriate initial management?

A 68-year-old male with pre-existing cervical spondylosis presents after a hyperextension injury to his neck from a fall. He has 2/5 motor strength in his upper extremities and 4/5 motor strength in his lower extremities. He has patchy sensory loss and urinary retention. Which of the following is the most likely diagnosis?

In total joint arthroplasty, which of the following modifications to ultra-high molecular weight polyethylene (UHMWPE) most effectively increases its resistance to adhesive and abrasive wear?

A 6-year-old girl sustains a displaced extension-type supracondylar humerus fracture. On presentation, her hand is pale with an absent radial pulse. After rapid closed reduction and percutaneous pinning, her hand becomes pink and capillary refill is less than 2 seconds, but the radial pulse remains unpalpable. What is the most appropriate next step in management?

A 32-year-old male sustains a closed tibia fracture and undergoes intramedullary nailing. Postoperatively, he complains of severe pain out of proportion to the injury, not relieved by opioids. Which of the following clinical signs is considered the most sensitive early indicator of acute compartment syndrome?

A 24-year-old elite baseball pitcher complains of vague, deep shoulder pain and decreased throwing velocity. He has a positive active compression test (O'Brien's). MR arthrogram reveals a Type II SLAP tear. What is the defining anatomical feature of a Type II SLAP tear?

A 21-year-old male falls onto an outstretched hand and presents with anatomic snuffbox tenderness. Initial radiographs are negative, but repeat imaging 2 weeks later shows a non-displaced fracture of the proximal pole of the scaphoid. What is the primary reason this fracture pattern is at a high risk for avascular necrosis?

When designing a posterior-stabilized (PS) total knee arthroplasty implant, the interaction between the femoral cam and the tibial post is engineered to replicate the function of which native structure?

A 65-year-old female presents with persistent, dull, aching back pain. Radiographs show a compressive fracture of L4 and multiple 'punched-out' lytic lesions in her skull. Serum protein electrophoresis reveals a monoclonal spike. Which of the following factors is primarily responsible for the osteolytic bone destruction seen in this disease process?

A 12-year-old premenarchal female presents with a right thoracic scoliosis curve of 35 degrees. Her Risser stage is 0. Which combination of factors indicates the highest risk for curve progression in adolescent idiopathic scoliosis?

An infant born with idiopathic congenital talipes equinovarus (clubfoot) is undergoing serial casting using the Ponseti method. Which of the following represents the correct sequence of deformity correction?

A 35-year-old female presents with knee pain. Radiographs reveal an eccentrically located, lytic epiphyseal lesion extending to the subchondral bone in the proximal tibia. Biopsy shows multinucleated giant cells interspersed with mononuclear stromal cells. Treatment with Denosumab is considered. Denosumab targets which of the following to arrest tumor progression?

A 40-year-old male sustains an anteroposterior compression (APC-III) pelvic ring injury and an associated perineal laceration with gross fecal contamination after a crushing industrial accident. Following application of a pelvic external fixator, his hemodynamics stabilize. What is the next most critical step in his management to reduce mortality?

Which of the following metal combinations represents the highest risk for galvanic corrosion when used together in an orthopaedic implant construct?

Which of the following vessels provides the predominant blood supply to the body of the talus?

In the biomechanical evaluation of viscoelastic materials such as ligaments and tendons, which of the following best defines the phenomenon of 'creep'?

Which zone of articular cartilage is characterized by the highest concentration of water, the lowest concentration of proteoglycans, and collagen fibers aligned parallel to the joint surface?

What is the most important independent prognostic factor for long-term survival in a patient with localized, high-grade intramedullary osteosarcoma?

A 24-year-old overhead athlete undergoes shoulder arthroscopy. The surgeon identifies a bucket-handle tear of the superior labrum that extends into the long head of the biceps tendon. According to the Snyder classification, what type of SLAP lesion is this?

A patient presents with an inability to form an 'OK' sign with their thumb and index finger. Examination reveals weakness in flexing the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which of the following muscles is additionally denervated in this syndrome?

During the ilioinguinal approach to the pelvis, the surgeon must carefully identify and ligate the 'corona mortis' to prevent catastrophic hemorrhage. This structure typically represents an anastomosis between which two vascular systems?

Which of the following is a recognized unique complication specific to ceramic-on-ceramic total hip arthroplasty bearing surfaces compared to other bearing options?

Which of the following pressure measurements is generally accepted as an absolute indication for emergent fasciotomy in a patient with a suspected acute compartment syndrome of the leg?

Tranexamic acid (TXA) is widely used in orthopedic surgery to reduce perioperative blood loss. Which of the following best describes its mechanism of action?

A 7-year-old boy from an endemic area presents with an acute, massive effusion of his right knee. He is afebrile and tolerating weight-bearing. Joint aspiration yields 45,000 WBCs/mm3 with 80% neutrophils. Serology for Borrelia burgdorferi is positive. What is the most appropriate initial treatment?

A 28-year-old male presents with a slow-growing, painful mass near his knee. Biopsy demonstrates a biphasic tumor with both epithelial and spindle cell components. Which of the following chromosomal translocations is pathognomonic for this soft tissue sarcoma?

A 35-year-old male is involved in a high-speed motor vehicle collision and sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). What is the classic mechanism of injury for this specific fracture pattern?

According to the Hueter-Volkmann law, which of the following biomechanical principles explains the progressive genu varum deformity seen in infantile Blount's disease?

A 55-year-old diabetic patient presents with a red, hot, swollen right foot and ankle. Radiographs show periarticular debris, fragmentation of the navicular, and subluxation of the midtarsal joints. According to the Eichenholtz classification, what is the most appropriate management at this stage?

In a 12-year-old male presenting with a unilateral slipped capital femoral epiphysis (SCFE), which of the following is an established indication for prophylactic in situ pinning of the asymptomatic contralateral hip?

In a patient with an L4-L5 degenerative spondylolisthesis and associated lumbar spinal stenosis, which nerve root is most commonly compressed, and where does the compression typically occur?

Which of the following conditions is an absolute requirement for primary (direct) bone healing to occur without the formation of a cartilaginous callus?

A 14-year-old boy presents with fever, weight loss, and a painful diaphyseal lesion of the femur. Radiographs reveal a permeative destructive lesion with an 'onion-skin' periosteal reaction. Histopathology shows small round blue cells. Which cell surface marker is characteristically highly expressed in this tumor?

A 24-year-old athlete undergoes an osteochondral autograft transfer for a femoral condyle defect. Which zone of articular cartilage is primarily responsible for resisting sheer stress and contains the highest concentration of collagen?

In modern total hip arthroplasty, highly cross-linked polyethylene (HXLPE) is commonly used to reduce wear rates. Which of the following manufacturing processes is utilized to eliminate free radicals generated during the cross-linking process and prevent subsequent in vivo oxidation?

A 38-year-old male is brought to the trauma bay after a motorcycle collision. He has a heart rate of 130 bpm and blood pressure of 75/40 mmHg. Pelvic radiographs show an anteroposterior compression type III (APC III) injury. After initiating massive transfusion protocols, what is the most appropriate initial mechanical intervention?

A 32-year-old female presents with knee pain and swelling. Radiographs show an eccentric, lytic epiphyseal lesion in the distal femur without a sclerotic rim. Biopsy confirms a giant cell tumor of bone. If medical therapy is considered, which of the following describes the mechanism of the most appropriate targeted agent?

A 3-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents note that the infant has stopped kicking her left leg. Examination reveals active hip flexion is absent, but hip adduction and ankle movements are intact. Which of the following is the most likely cause of this complication?

A 45-year-old male undergoes a spinal fusion using a structural cortical freeze-dried allograft. Which of the following best describes the predominant mechanism of initial graft incorporation?

A 14-year-old boy presents with a permeative lytic lesion in the femoral diaphysis with a periosteal "onion skin" reaction. Biopsy reveals small blue round cells. Which of the following translocations is most characteristic of this tumor?

During the Ponseti method of serial casting for idiopathic clubfoot, what is the correct biomechanical sequence of deformity correction?

A 68-year-old female presents with a painful total knee arthroplasty 2 years postoperatively. Aspiration reveals a synovial fluid WBC count of 35,000 cells/mcL with 92% PMNs. Components are well-fixed on radiographs. Which of the following is the most appropriate definitive management?

A 72-year-old man presents with bilateral leg pain and heaviness that worsens with walking and is relieved by leaning over a shopping cart. MRI shows severe L4-L5 central canal stenosis. Which ligament hypertrophies and primarily contributes to this stenosis?

During an open carpal tunnel release, the surgeon must be careful to avoid injuring the recurrent motor branch of the median nerve. Through which of the following muscles does the transmuscular variant of this nerve pass?

A 35-year-old male is brought to the ED after a motorcycle crash. Pelvic radiographs show an APC-III pelvic ring injury. He remains hemodynamically unstable despite a pelvic binder and massive transfusion protocols. What is the most appropriate next step in surgical management?

A 24-year-old football player sustains a hyperplantarflexion injury to his foot. Radiographs show a "fleck sign" at the base of the second metatarsal. The primary stabilizing ligament of this joint connects which two structural bones?

A 12-year-old obese male presents with left knee pain and an antalgic gait. Exam reveals obligatory external rotation of the hip upon passive flexion. Following in situ pinning of a severe slipped capital femoral epiphysis, the patient develops a rapid loss of joint space and progressive stiffness. What is the most likely diagnosis?

Bone morphogenetic proteins (BMPs) are osteoinductive growth factors belonging to the TGF-beta superfamily. Which of the following BMPs is an FDA-approved biologically active protein used as an adjunct in acute open tibia fractures?

A 55-year-old laborer undergoes an arthroscopic massive rotator cuff repair. Six months postoperatively, MRI reveals a retear. Which of the following preoperative MRI findings is most strongly associated with structural failure of rotator cuff healing?

A 30-year-old man sustains a closed high-energy tibial shaft fracture. Eight hours later, he develops excruciating pain out of proportion to the injury. Which of the following is the most sensitive and earliest clinical finding for acute compartment syndrome?

In total hip arthroplasty, the use of highly cross-linked polyethylene (HXLPE) has significantly reduced wear rates. Which of the following mechanical trade-offs is a direct consequence of increasing the radiation dose to maximize cross-linking?

A 45-year-old male sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following an MVC. Radiographs show a 4mm displacement and 12 degrees of angulation. According to the Levine and Edwards classification, which of the following is the mechanism of this Type II injury?

A 16-year-old boy is diagnosed with a high-grade intramedullary osteosarcoma of the distal femur. He undergoes neoadjuvant chemotherapy followed by wide surgical resection. Pathological analysis of the resected specimen shows 95% tumor necrosis. What does this percentage primarily indicate?

A 28-year-old female falls from a height and sustains a Hawkins Type III fracture of the talar neck. Which of the following best describes the articulations dislocated in this injury pattern?

Regarding the ultrastructure of hyaline articular cartilage, which zone contains the highest concentration of proteoglycans, the lowest concentration of water, and chondrocytes arranged in columns?

An 8-month-old female with neglected developmental dysplasia of the hip (DDH) undergoes closed reduction and spica casting. Postoperatively, what is the most significant risk associated with casting the hip in excessive abduction (greater than 60 degrees)?

A 30-year-old carpenter sustains a volar laceration over the proximal phalanx of his index finger, transecting both the FDS and FDP tendons. According to the Verdan classification, which zone of flexor tendon injury does this represent?

Which cytokine is secreted by osteoblasts to directly stimulate osteoclast differentiation by binding to its specific receptor on the surface of osteoclast precursors?

Which zone of articular cartilage is characterized by the highest concentration of water and collagen fibers that are oriented parallel to the articular surface?

A 68-year-old male presents with a painful total knee arthroplasty 3 years post-operatively. Which biomarker, measured in synovial fluid, directly binds to and neutralizes microbial cell membranes and is highly specific for periprosthetic joint infection?

A 32-year-old male sustains a closed tibia fracture and develops worsening leg pain. Compartment pressures are measured. What pressure threshold is most universally accepted as an absolute indication for emergency fasciotomy?

A 13-year-old obese male presents with an obligatory external rotation of the hip during active flexion. Radiographs confirm a slipped capital femoral epiphysis (SCFE). This physical exam finding is due to the displacement of the femoral neck in which direction relative to the epiphysis?

A 55-year-old female with short bowel syndrome presents with diffuse bone pain and symmetric Looser zones on radiographs. What is the expected laboratory profile for her condition?

A 24-year-old male sustains a displaced proximal pole scaphoid fracture. The primary blood supply at highest risk of disruption enters the scaphoid at which anatomic location?

According to Perren's strain theory, providing absolute fracture stability with less than 2% interfragmentary strain will promote which specific type of bone healing?

During a primary posterior-stabilized total knee arthroplasty, the surgeon uses spacer blocks and notes that the knee is tight in flexion but balanced and stable in extension. Which of the following is the most appropriate next step to balance the knee?

A 15-year-old male presents with a distal femur destructive lesion with a Codman triangle. Biopsy reveals malignant spindle cells producing osteoid. What is the most significant prognostic factor for overall survival in this condition?

A 6-week-old female treated with a Pavlik harness for developmental dysplasia of the hip lacks active knee extension on the affected side at a 2-week follow-up. This complication is most likely caused by which positioning error?

A 40-year-old hypotensive male presents with an anteroposterior compression type III (APC-III) pelvic ring injury. To be most effective in reducing pelvic volume and venous bleeding, a pelvic binder must be centered directly over which anatomic landmarks?

A 45-year-old male presents with acute urinary retention, saddle anesthesia, and bilateral leg weakness secondary to a massive L4-L5 disc herniation. Current literature indicates that to maximize the chance of urologic recovery, surgical decompression should ideally be performed within what time frame from symptom onset?

The introduction of highly cross-linked polyethylene (HXLPE) in total hip arthroplasty has drastically reduced the incidence of osteolysis primarily by decreasing which specific mechanism of wear?

During an in-situ decompression of the ulnar nerve for cubital tunnel syndrome, the surgeon releases the fascial band spanning the two heads of the flexor carpi ulnaris muscle. What is the eponym for this anatomic structure?

Following anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft, the graft undergoes ligamentization. During which phase is the graft structurally and mechanically at its weakest?

A 28-year-old male sustains a Gustilo-Anderson type IIIB open tibia fracture in a motorcycle collision. According to established trauma guidelines, what is the single most critical modifiable factor in reducing the risk of deep infection?

In a 7-year-old boy diagnosed with Legg-Calve-Perthes disease, which of the following classification systems is considered the most reliable radiographic prognostic indicator when assessed at the time of maximal epiphyseal fragmentation?

Bone morphogenetic proteins (BMPs) initiate intracellular signaling by binding to specific membrane-bound serine/threonine kinase receptors. This directly leads to the phosphorylation and nuclear translocation of which intracellular transcription factors?