Musculoskeletal Board Prep

MSK accounts for 8 to 10 percent of the ABFM. Master joint exam, imaging decisions, and conservative management for the most common primary care complaints.

Musculoskeletal medicine is one of the larger content areas on the ABFM Family Medicine boards, contributing 8 to 10 percent of total questions. That share reflects how much MSK shows up in everyday practice — back pain alone accounts for an enormous share of primary care visits, and joint complaints (knee, shoulder, hip) follow closely. The exam favors clinical reasoning over imaging interpretation: you will be asked when to image, not what the MRI shows.

Low back pain is the highest-yield single topic in MSK. The American College of Physicians and American Academy of Family Physicians both recommend conservative management as first-line for non-specific acute low back pain: reassurance, education on natural history (most cases resolve in 4 to 6 weeks), heat, exercise, and NSAIDs or acetaminophen. Imaging is reserved for red flags: trauma, age over 70 with first episode, fever, weight loss, neurological deficit, history of cancer, IV drug use, or immunocompromise. Cauda equina syndrome (saddle anesthesia, urinary retention, bilateral leg weakness) requires emergent MRI and neurosurgical consultation. The ABFM tests this conservative-first paradigm and the red flag list directly.

Knee complaints are the second-most tested MSK area. Common scenarios include osteoarthritis (chronic, weight-bearing, morning stiffness under 30 minutes), meniscal tears (acute twisting injury, joint line tenderness, locking or catching), ACL tears (sudden pop, swelling, instability), and patellofemoral pain (anterior knee pain with stairs, prolonged sitting). The Ottawa knee rules guide imaging in acute injury: X-ray indicated for age over 55, isolated patellar tenderness, fibular head tenderness, inability to flex past 90 degrees, or inability to bear weight for four steps both immediately and in the ER.

Shoulder pain centers on rotator cuff disorders (impingement, tendinopathy, partial tears), adhesive capsulitis (frozen shoulder, especially in diabetics), and acromioclavicular separations. Conservative management — physical therapy, NSAIDs, activity modification — is first-line for nearly all atraumatic chronic shoulder pain. Surgical referral is for full-thickness rotator cuff tears in active patients, instability, or failed conservative management at 6 to 12 weeks.

Inflammatory arthropathies (gout, pseudogout, rheumatoid arthritis, polymyalgia rheumatica) round out the high-yield list. Acute gout is treated with NSAIDs, colchicine, or oral steroids; do not change urate-lowering therapy during an attack. Chronic urate-lowering therapy (allopurinol, febuxostat) is indicated for two or more attacks per year, tophi, or chronic kidney disease. The 2020 ACR gout guidelines support a treat-to-target approach with serum uric acid under 6 mg/dL. Rheumatoid arthritis suspicion (symmetric small-joint inflammation, morning stiffness over 1 hour, positive RF or anti-CCP) warrants urgent rheumatology referral for early DMARD initiation.

High-yield musculoskeletal topics

• Low back pain red flags and imaging. Image with MRI for: cauda equina syndrome, suspected infection or malignancy, progressive neurological deficit, trauma in osteoporotic patient. Plain films first for: trauma, suspected fracture, age over 70 with first episode. No imaging for non-specific acute low back pain in the absence of red flags.
• Acute gout management and chronic urate-lowering therapy. Acute attack: NSAIDs, colchicine (1.2 mg then 0.6 mg one hour later), or oral prednisone. Do not start or stop urate-lowering therapy during an attack. Indications for chronic ULT: two or more attacks per year, tophi, CKD stage 2 or higher, urolithiasis. Allopurinol first-line, target serum uric acid under 6.
• Knee osteoarthritis management. First-line: weight loss, exercise (quadriceps strengthening, low-impact aerobic), topical NSAIDs (especially in older adults). Oral NSAIDs second-line. Intra-articular corticosteroid injection for moderate symptoms. Refer for total knee arthroplasty when pain limits activities of daily living despite optimal conservative management.
• Rotator cuff disease evaluation. Painful arc 60 to 120 degrees suggests impingement. Drop-arm test, empty can test, lift-off test localize specific tendons. MRI or ultrasound for suspected full-thickness tear in active patient who would consider surgery. Conservative management (PT, NSAIDs, subacromial steroid injection) for 6 to 12 weeks before imaging in chronic atraumatic cases.
• Plantar fasciitis. Heel pain worst with first steps in morning, improves with activity. Diagnosis is clinical. First-line: stretching (Achilles and plantar fascia), supportive footwear, orthotics, weight loss. NSAIDs for symptom relief. Corticosteroid injection for refractory cases (caution: rupture risk). Most resolve within 12 months.
• Polymyalgia rheumatica vs giant cell arteritis. PMR: bilateral shoulder and hip girdle pain and stiffness, age over 50, ESR over 40, dramatic response to low-dose prednisone (15 to 20 mg). GCA: temporal headache, jaw claudication, vision changes, scalp tenderness; emergent treatment with high-dose prednisone (60 mg) and temporal artery biopsy. Up to 20 percent of PMR patients have or develop GCA.
• Carpal tunnel syndrome. Median nerve symptoms (thumb, index, middle, radial half of ring finger), worse at night, awakens patient. Provocative tests: Phalen, Tinel. First-line: night splints, activity modification, NSAIDs. Steroid injection for moderate symptoms. Surgical release for severe symptoms, thenar atrophy, or failed conservative management.
• Sprains and Ottawa rules. Ottawa ankle rules: X-ray for bone tenderness at posterior edge of medial or lateral malleolus, navicular, or base of fifth metatarsal, OR inability to bear weight four steps. Ottawa knee rules: similar logic for knee. PRICE (protection, rest, ice, compression, elevation) plus early mobilization. Most ankle sprains heal in 2 to 6 weeks.

ABFM exam tips

For low back pain, the default answer is "no imaging." Unless red flags are present, conservative management without imaging is the standard of care. The exam tests this aggressively because over-imaging is one of the most common errors in primary care MSK.

Memorize the Ottawa rules cold. Ankle, knee, and foot rules each have specific criteria. The exam will give you a vignette with subtle physical exam findings and ask whether to X-ray. Knowing the rules prevents both over- and under-imaging.

Recognize cauda equina syndrome instantly. Saddle anesthesia, urinary retention or incontinence, fecal incontinence, bilateral lower extremity weakness — emergent MRI and neurosurgical consult. This is one of the few MSK emergencies and is tested for both recognition and management.

For gout, do not change ULT during an attack. Acute treatment is NSAIDs, colchicine, or steroids. If the patient is already on allopurinol, continue it. If they are not, do not start it during the acute attack — wait until inflammation resolves, then start at low dose and titrate. The exam tests this sequencing directly.

Differentiate inflammatory from non-inflammatory joint pain. Inflammatory features: morning stiffness over 1 hour, improves with activity, warmth, swelling, elevated CRP/ESR. Non-inflammatory (osteoarthritis): morning stiffness under 30 minutes, worsens with activity, no systemic features. This differentiation drives workup choice.

Know when to refer for total joint replacement. Severe symptoms limiting ADLs despite optimal conservative therapy (weight loss, PT, NSAIDs, injections) is the threshold. The exam loves to ask "what is the next step" for a patient who has tried everything — the answer is orthopedic referral, not another injection.

Common pitfalls

Do not order MRI for non-specific acute low back pain. Imaging in the absence of red flags is not just unnecessary — it leads to incidental findings that drive unnecessary surgery and worse outcomes. The Choosing Wisely campaign and ACP guidelines both highlight this. The exam tests it.

Do not start allopurinol during an acute gout flare. Initiating urate-lowering therapy during an attack can prolong it. Wait until the inflammation resolves, then start low (100 mg daily) and titrate to target. If the patient is already on allopurinol when they flare, continue it without dose change.

Do not give oral steroids long-term for chronic shoulder or knee pain. Systemic corticosteroids for chronic MSK pain accelerate joint damage and have unacceptable side effects. Local injections are appropriate; chronic oral therapy is not.

Do not miss giant cell arteritis in older patients with new headache. New temporal headache, jaw claudication, vision changes, or polymyalgia rheumatica symptoms in a patient over 50 require immediate high-dose prednisone (60 mg) and temporal artery biopsy. Delaying treatment risks permanent vision loss.

Do not over-rely on imaging for rotator cuff disease. MRI is sensitive for partial tears, but partial-thickness tears in older adults are extremely common and often asymptomatic. Image only when imaging will change management — typically when surgery is being considered.

Do not use opioids as first-line for chronic non-cancer MSK pain. Per CDC 2022 guidelines, opioids are not first-line for chronic pain. Maximize non-opioid approaches (PT, exercise, NSAIDs, acetaminophen, topical agents, injections, behavioral interventions) before considering opioids, and avoid them entirely if possible. The exam tests this.

Do not treat asymptomatic hyperuricemia. Elevated uric acid alone, without gout attacks or tophi, does not warrant urate-lowering therapy. Treat the disease, not the lab.

Frequently asked questions

How much MSK is on the ABFM exam?

Musculoskeletal content typically makes up 8 to 10 percent of the ABFM exam, or roughly 25 to 30 questions per full exam. Low back pain, knee complaints, shoulder pain, and inflammatory arthropathies (gout, RA, polymyalgia rheumatica) account for the majority.

What are the red flags for low back pain?

Trauma, age over 70 with first episode, history of cancer, fever, weight loss, IV drug use, immunocompromise, progressive neurological deficit, saddle anesthesia, urinary retention or incontinence (cauda equina), and prior spinal surgery. Any of these warrants imaging and possibly urgent referral. Without red flags, conservative management without imaging is appropriate.

Should I memorize the Ottawa ankle and knee rules?

Yes. Ottawa ankle rules: X-ray for bone tenderness at posterior edge of medial or lateral malleolus, navicular, or base of fifth metatarsal, or inability to bear weight four steps. Ottawa knee rules: age over 55, isolated patellar tenderness, fibular head tenderness, inability to flex past 90 degrees, or inability to bear weight for four steps. These appear directly on board questions.

How is acute gout treated on the boards?

NSAIDs (indomethacin, naproxen), colchicine (1.2 mg then 0.6 mg one hour later), or oral prednisone (40 mg daily for 5 days), all roughly equivalent in efficacy. Choose based on comorbidities. Do not start or stop urate-lowering therapy during an attack. Begin chronic ULT after the flare resolves if indicated.

When should I order an MRI for shoulder pain?

For traumatic injuries with suspected full-thickness rotator cuff tear in patients who would consider surgery, for failed conservative management at 6 to 12 weeks, for suspected labral pathology with mechanical symptoms, or for atypical features. Routine MRI for chronic atraumatic shoulder pain in older adults is not warranted because incidental findings are common and rarely change management.

How do I distinguish inflammatory from non-inflammatory arthritis?

Inflammatory: morning stiffness over 60 minutes, improves with activity, warmth, swelling, elevated CRP or ESR, possible systemic symptoms (fatigue, weight loss). Non-inflammatory (osteoarthritis): morning stiffness under 30 minutes, worsens with activity, less swelling, normal inflammatory markers. This distinction drives whether to pursue rheumatology referral and DMARDs.

When is rheumatology referral indicated for joint pain?

Suspected rheumatoid arthritis (symmetric small joint inflammation, morning stiffness over 1 hour, positive RF or anti-CCP), suspected spondyloarthropathy (inflammatory back pain in young adult), refractory gout or other crystal arthropathy, suspected connective tissue disease, or any unexplained inflammatory arthritis. Early DMARD initiation in RA prevents joint damage, so referral should be prompt.