# Clinical Cases: Musculoskeletal Conditions in Primary Care ## Case 1: Knee Osteoarthritis ### Patient Demographics - **Age:** 62 years old - **Sex:** Female - **Occupation:** Retired postal worker ### Chief Complaint "My right knee has been hurting for months, and it's getting harder to walk." ### History of Present Illness Mrs. Patricia Williams is a 62-year-old woman presenting with progressive right knee pain over 6 months. The pain is described as a deep ache, worse with weight-bearing activities like walking and climbing stairs. She reports morning stiffness lasting about 20 minutes that improves with movement. The knee occasionally "gives way" when walking, and she has noticed mild swelling at the end of the day. She has been taking ibuprofen 400 mg twice daily with partial relief. No history of knee trauma, locking, or significant swelling. She notes increasing difficulty with her daily walks and has stopped attending her water aerobics class due to pain getting to the pool. ### Past Medical History - Hypertension - Obesity - Gastroesophageal reflux disease - Bilateral hip replacement 8 years ago (for osteoarthritis) ### Family History - Mother: Osteoarthritis, knee replacement - Father: Hypertension ### Social History - Never smoker - Occasional alcohol - Widowed, lives alone in two-story home - Previously active, now limited by knee pain ### Physical Examination - **Vital Signs:** BP 134/82 mmHg, HR 72, BMI 33 - **General:** Well-appearing, antalgic gait favoring right leg - **Right Knee:** - Mild warmth, small effusion - Bony enlargement along medial joint line - Crepitus with range of motion - Tenderness along medial joint line - Range of motion: 5-120 degrees (slight flexion contracture) - Ligaments stable, negative McMurray test - No popliteal fullness (Baker's cyst) - **Left Knee:** Minimal crepitus, no effusion, full ROM ### Clinical Image ![Knee osteoarthritis X-ray](case_01_image.jpg) *Image: Anteroposterior radiograph of a knee with osteoarthritis demonstrating medial joint space narrowing, osteophyte formation, and subchondral sclerosis, characteristic findings of degenerative joint disease.* **Image Source:** Wikimedia Commons **Attribution:** James Heilman, MD, CC BY-SA 3.0 **URL:** https://commons.wikimedia.org/wiki/File:Osteoarthritis_of_the_left_knee.jpg ### Outpatient Workup - Right knee X-ray (weight-bearing AP, lateral, sunrise views): - Medial compartment joint space narrowing - Osteophyte formation medially - Subchondral sclerosis - Kellgren-Lawrence Grade 3 - Labs (if inflammatory arthritis suspected): Not indicated given classic OA presentation ### Assessment and Diagnosis 1. **Right knee osteoarthritis, moderate-severe** - Kellgren-Lawrence Grade 3, significant functional impairment 2. **Obesity** - Contributing to joint stress 3. **GERD** - Limits NSAID use 4. **Chronic NSAID use concern** - Risk of GI and renal complications ### Management Plan **Non-Pharmacologic:** - Weight loss counseling: Every pound lost = 4 pounds less force on knee - Physical therapy referral: Quadriceps strengthening, ROM exercises - Low-impact exercise: Swimming, water aerobics, stationary cycling - Assistive devices: Cane for opposite hand, consider knee brace - Heat/ice therapy for symptom relief **Pharmacologic:** - Discontinue scheduled ibuprofen (GERD, chronic use risks) - Topical diclofenac gel 1% applied 4 times daily to knee (first-line, lower systemic risk) - Acetaminophen 1000 mg every 8 hours as needed (max 3 g/day) - If topical inadequate: Duloxetine 30-60 mg daily (SNRI approved for chronic musculoskeletal pain, also helps mood) **Injection Therapy:** - Intra-articular corticosteroid injection: Triamcinolone 40 mg - Can provide 4-12 weeks of relief - Limit to 3-4 injections per year per joint - Discuss that injections are temporizing, not disease-modifying **Referral Considerations:** - Orthopedic surgery referral for joint replacement evaluation if: - Failed conservative management - Significant functional limitation - Continued pain affecting quality of life - Discuss patient's goals and expectations ### Follow-Up - Return in 6-8 weeks to assess response to conservative measures - Repeat injection in 3-4 months if initial response but recurrence - Consider orthopedic referral if not responding ### Teaching Points 1. **Clinical diagnosis of knee OA:** Based on age >50, morning stiffness <30 minutes, crepitus, bony tenderness, bony enlargement, and no palpable warmth. X-ray confirms but is not always necessary for diagnosis. 2. **Weight management:** Most important modifiable risk factor. Each kilogram of weight loss results in 4-fold reduction in load on knee with each step. 3. **Stepped approach to OA management:** - First-line: Education, exercise, weight loss, topical NSAIDs - Second-line: Oral NSAIDs (short-term), duloxetine, intra-articular steroids - Third-line: Surgical referral (arthroplasty) 4. **NSAID cautions:** In this patient with GERD and chronic use, prefer topical NSAIDs or alternatives. If oral NSAIDs needed, use lowest effective dose for shortest duration with PPI. --- ## Case 2: Acute Low Back Pain ### Patient Demographics - **Age:** 38 years old - **Sex:** Male - **Occupation:** Warehouse supervisor ### Chief Complaint "I threw out my back 3 days ago lifting boxes, and I can barely move." ### History of Present Illness Mr. Michael Johnson is a 38-year-old man presenting with acute low back pain that began 3 days ago while lifting heavy boxes at work. He felt sudden pain in his lower back with radiation to his right buttock. The pain is described as sharp and aching, rated 8/10, worse with bending, sitting, and transitioning from sitting to standing. He has been lying flat most of the time for relief. He denies leg weakness, numbness, bowel or bladder changes, or saddle anesthesia. He has taken ibuprofen and used a heating pad with minimal relief. No fever or weight loss. No history of trauma beyond the lifting incident. He had a similar episode 2 years ago that resolved with rest over 2 weeks. ### Past Medical History - Prior low back strain (2 years ago) - No surgeries - No chronic medical conditions ### Family History - Father: Chronic low back pain - Mother: Healthy ### Social History - Non-smoker - Social alcohol on weekends - Works as warehouse supervisor (heavy lifting, standing) - Married, two young children - No regular exercise program ### Physical Examination - **Vital Signs:** BP 128/78 mmHg, HR 80, Afebrile, BMI 28 - **General:** Appears uncomfortable, guarded movements, holds lower back - **Gait:** Slow, antalgic, avoids lumbar flexion - **Spine:** - Paravertebral muscle spasm bilateral lower lumbar region - Tenderness L4-S1 paravertebral muscles - Decreased lumbar flexion (50% of normal) due to pain - Extension mildly limited - No midline spinous process tenderness - No step-off deformity - **Neurologic:** - Straight leg raise: Negative bilaterally (no radicular pain) - Motor: 5/5 hip flexors, knee extensors, ankle dorsiflexors, great toe extensors bilaterally - Sensation: Intact light touch bilateral lower extremities - Reflexes: 2+ patellar, 2+ Achilles bilaterally - No saddle anesthesia - Rectal tone normal (assessed given importance of red flag screening) ### Assessment and Diagnosis 1. **Acute mechanical low back pain** - Strain/sprain, no red flags identified 2. **No neurologic deficits** - Normal neurologic examination 3. **Favorable prognosis** - Most acute low back pain resolves within 4-6 weeks ### Management Plan **Patient Education (Critical Component):** - Reassurance: Most low back pain improves significantly within 4-6 weeks - Avoid bed rest: Stay active as tolerated, bed rest does not help and may prolong recovery - Continue normal activities within pain tolerance - Explain lack of red flags and why imaging is not needed **Pharmacologic:** - NSAIDs: Ibuprofen 600 mg every 8 hours with food x 1-2 weeks (more effective than acetaminophen for acute LBP) - Muscle relaxant (short-term): Cyclobenzaprine 10 mg at bedtime x 5-7 days for spasm - Avoid opioids for routine acute LBP **Non-Pharmacologic:** - Ice or heat based on preference (both acceptable) - Gentle stretching when acute pain subsides - Physical therapy referral if not improving in 2-4 weeks **Work Considerations:** - Work note for light duty x 1 week (no lifting >10 lbs) - Gradual return to full duty - Discuss proper lifting mechanics **Red Flags to Return Immediately:** - New leg weakness or numbness - Bowel or bladder dysfunction (incontinence or retention) - Saddle anesthesia - Fever - Worsening pain despite treatment ### Follow-Up - Return in 2 weeks if not significantly improved - Earlier if any red flag symptoms develop - Consider imaging and physical therapy if pain persists beyond 4-6 weeks ### Teaching Points 1. **Red flags in low back pain (requiring urgent evaluation):** - Cauda equina syndrome: Saddle anesthesia, bladder dysfunction, bilateral leg weakness - Cancer: History of cancer, unexplained weight loss, age >50 or <18, pain at rest - Infection: Fever, IV drug use, immunosuppression, recent infection - Fracture: Significant trauma, osteoporosis, steroid use - Severe/progressive neurologic deficit 2. **Imaging not indicated in acute LBP:** Without red flags, imaging (X-ray, MRI) in the first 4-6 weeks does not improve outcomes and may lead to unnecessary intervention. Incidental findings are common and may cause patient anxiety. 3. **Stay active:** Bed rest is not recommended and may prolong recovery. Patients should maintain normal activities as tolerated. 4. **Natural history:** 90% of acute low back pain resolves within 6 weeks regardless of treatment. The goal is symptom management and functional restoration. 5. **NSAIDs vs. opioids:** NSAIDs are first-line and more effective than acetaminophen for acute LBP. Opioids not recommended for routine acute LBP due to lack of superior efficacy and risk of dependence.