6.9 Regional Musculoskeletal Syndromes, Back Pain & Sports Injuries

1. Low Back Pain

The first task is triage into three categories: non-specific mechanical pain (about 85%), radiculopathy or spinal stenosis, and serious underlying pathology (well under 5%).

Red flags that change management

Without red flags, do not image. Early imaging does not improve outcomes, and degenerative findings are ubiquitous in asymptomatic adults — disc bulges and facet arthropathy are present in most people over 50. Imaging generates procedures rather than answers.

Management of non-specific pain: remain active (bed rest worsens outcomes), heat, NSAIDs or acetaminophen, and physical therapy for persistent symptoms. Opioids and systemic corticosteroids are not indicated for acute non-specific back pain.

Nerve root syndromes and spinal stenosis

These are enumerated in the blueprint under Neurology as nerve root syndromes and mechanical lesions of the spine.

Lumbar spinal stenosis produces neurogenic claudication: bilateral buttock and leg pain worsened by standing and walking, relieved by sitting or lumbar flexion. Patients report walking further when leaning on a shopping cart. The critical contrast is with vascular claudication, which is relieved by standing still, is not posture-dependent, and comes with diminished pulses and a reduced ankle-brachial index.

2. Shoulder

The single most useful discriminator is passive range of motion. Preserved passive range with painful active motion indicates a cuff or bursal problem; restricted passive range indicates capsular or glenohumeral disease.

3. Elbow, Wrist and Hand

• Lateral epicondylosis (tennis elbow): pain over the lateral epicondyle, worse with resisted wrist extension. Overwhelmingly the more common of the two.
• Medial epicondylosis (golfer elbow): pain with resisted wrist flexion and pronation.
• Olecranon bursitis: fluctuant posterior swelling. Aspirate if warm, red or febrile — septic bursitis is common here.
• De Quervain tenosynovitis: radial wrist pain; positive Finkelstein test; classic in new parents and in repetitive thumb use.
• Carpal tunnel syndrome: nocturnal paresthesia in the median distribution with thenar wasting in advanced disease. Associations include pregnancy, hypothyroidism, diabetes, obesity, acromegaly and amyloidosis. Nocturnal wrist splinting is first-line.
• Dupuytren contracture: painless palmar fascial cords with flexion contracture, most often of the fourth and fifth digits.
• Trigger finger: catching or locking with a palpable A1 pulley nodule.

4. Hip and Pelvis

Localizing the pain determines the differential, and this is the reasoning the exam rewards:

Lateral hip pain is rarely true bursitis. It is usually gluteal tendinopathy, and the term greater trochanteric pain syndrome reflects that. It responds to load management and eccentric strengthening rather than to repeated injection.

Meralgia paresthetica — burning numbness over the anterolateral thigh from lateral femoral cutaneous nerve compression — is purely sensory with no weakness and no reflex change. It is associated with obesity, tight belts and pregnancy, and it is enumerated in the blueprint under peripheral neuropathy.

5. Knee

Rapid effusion after injury: blood within two hours indicates anterior cruciate ligament tear, osteochondral fracture or patellar dislocation. Slower effusion over a day is more typical of meniscal injury.

The Ottawa knee rules identify who needs radiography after acute injury: age 55 or older, isolated patellar tenderness, fibular head tenderness, inability to flex to 90 degrees, or inability to bear weight for four steps both immediately and in the emergency department.

6. Foot and Ankle

• Plantar fasciitis: heel pain worst with the first steps in the morning and after rest; point tenderness at the medial calcaneal tubercle. Treated with stretching, supportive footwear and load reduction. Imaging is unnecessary, and heel spurs are incidental.
• Achilles tendinopathy: posterior heel pain; fluoroquinolone use is a recognized precipitant of tendinopathy and rupture.
• Achilles rupture: audible pop, palpable gap, positive Thompson test (no plantar flexion on calf squeeze).
• Morton neuroma: burning pain in the third web space with a palpable click on lateral compression.
• Tarsal tunnel syndrome: burning plantar pain from posterior tibial nerve compression.

The Ottawa ankle rules limit unnecessary radiography: image only with bone tenderness at the posterior edge or tip of either malleolus, tenderness at the navicular or base of the fifth metatarsal, or inability to bear weight for four steps.

7. Sports Injuries and Trauma

A separately enumerated blueprint subsection. The internist-facing points:

• Overuse injuries — stress fracture, tendinopathy, medial tibial stress syndrome — result from training errors, most commonly a rapid increase in volume or intensity. Stress fractures are frequently invisible on initial radiographs; MRI is the sensitive test, and a normal early film does not exclude one.
• The female athlete triad / relative energy deficiency in sport — low energy availability, menstrual dysfunction and low bone density — is a cause of stress fractures in young women and requires nutritional rather than orthopedic management.
• Concussion is a clinical diagnosis; imaging is normal. Return to play follows a graduated protocol, and an athlete should never return the same day.
• Exertional rhabdomyolysis presents with severe muscle pain, weakness and dark urine after unaccustomed exertion; treatment is aggressive intravenous fluid.
• Exercise-associated hyponatremia results from excessive hypotonic fluid intake during endurance events and is treated with hypertonic saline, not with more free water.