PANCE Musculoskeletal 4 — Questions and Answers
Question 1: A 16-year-old obese male presents with left hip and knee pain and a limp. The hip is held in external rotation. What is the most likely diagnosis?
- Legg-Calvé-Perthes disease
- Septic arthritis
- Slipped capital femoral epiphysis (Correct answer)
- Transient synovitis
Correct answer: Slipped capital femoral epiphysis
Slipped capital femoral epiphysis (SCFE) occurs in obese adolescent males, presenting with hip/knee pain and obligate external rotation of the hip; urgent surgical pinning is required.
Question 2: A 55-year-old man presents with low back pain radiating down the posterior leg to the foot, worsened by sitting and relieved by standing. Straight leg raise is positive at 40°. What is the most likely diagnosis?
- Lumbar spinal stenosis
- Piriformis syndrome
- L4-L5 disc herniation (Correct answer)
- Cauda equina syndrome
Correct answer: L4-L5 disc herniation
A positive straight leg raise test at less than 45° is highly sensitive for lumbar disc herniation causing nerve root compression and radiculopathy.
Question 3: A 70-year-old male presents with bilateral leg cramping when walking that is relieved by leaning forward or sitting. MRI shows narrowing of the lumbar spinal canal. What is the diagnosis?
- Peripheral arterial disease
- Lumbar spinal stenosis (Correct answer)
- L4 disc herniation
- Deep vein thrombosis
Correct answer: Lumbar spinal stenosis
Lumbar spinal stenosis causes neurogenic claudication with pain relieved by flexion (leaning forward), distinguishing it from vascular claudication which improves with rest alone.
Question 4: A patient with a distal radius fracture develops loss of thumb opposition and thenar atrophy 3 months after casting. Which nerve is involved?
- Radial nerve
- Ulnar nerve
- Median nerve (Correct answer)
- Anterior interosseous nerve
Correct answer: Median nerve
The median nerve innervates the thenar muscles and provides thumb opposition; it can be compressed in carpal tunnel syndrome, which is a known complication of distal radius fractures.
Question 5: A 25-year-old basketball player twists his knee and feels a pop. He develops a knee effusion within 2 hours and has a positive Lachman test. What structure is most likely injured?
- Posterior cruciate ligament
- Medial collateral ligament
- Anterior cruciate ligament (Correct answer)
- Lateral meniscus
Correct answer: Anterior cruciate ligament
ACL tears present with a pop, rapid hemarthrosis, and positive Lachman test; they are common in pivoting sports like basketball.
Question 6: A 48-year-old woman with a history of breast cancer presents with severe back pain and new bilateral leg weakness with bowel/bladder incontinence. What is the most urgent next step?
- Lumbar X-ray
- Outpatient MRI in 2 weeks
- Emergency MRI of the spine and neurosurgical consult (Correct answer)
- Empiric corticosteroids and discharge
Correct answer: Emergency MRI of the spine and neurosurgical consult
Malignant spinal cord compression is a surgical emergency requiring immediate MRI and neurosurgical evaluation to prevent permanent neurological deficits.
Question 7: A 22-year-old female with hypermobile joints presents with recurrent shoulder dislocations. Anterior apprehension test is positive. What is the most common direction of glenohumeral instability?
- Posterior
- Inferior
- Anterior (Correct answer)
- Multidirectional
Correct answer: Anterior
Anterior shoulder instability is the most common type, often due to labral tears (Bankart lesion) following trauma or repetitive stress in hypermobile individuals.
PANCE Musculoskeletal 4
A 16-year-old obese male presents with left hip and knee pain and a limp.
The hip is held in external rotation.
What is the most likely diagnosis?