What is the appropriate treatment for a 16-year-old basketball player with pain on the upper right lateral portion of the knee and swelling in the back of the knee after a defensive slide and fall?

Acute Lateral Knee Injury in Adolescent Athlete

Immediate Management

This 16-year-old basketball player most likely has a lateral collateral ligament (LCL) injury with associated popliteal effusion and should be treated with the PRICE protocol (Protection, Rest, Ice, Compression, Elevation) immediately, followed by urgent orthopedic evaluation within 24-48 hours to rule out multi-ligament injury or neurovascular compromise. 1

The mechanism (defensive slide with fall) combined with lateral upper knee pain and posterior swelling suggests a lateral-sided ligament injury, potentially with associated posterolateral corner involvement. The posterior swelling (popliteal fossa) is concerning for either a significant effusion tracking posteriorly or a Baker's cyst, though the latter is less likely in acute trauma. 2

Initial Assessment Priorities

Red Flags Requiring Urgent Referral

• Severe pain with inability to bear weight - requires immediate orthopedic evaluation 3
• Neurovascular compromise - check for intact pulses, sensation, and motor function in the affected limb 4
• Joint instability - test for excessive lateral laxity suggesting complete ligament disruption 1
• Tense, painful effusion - may require aspiration for symptomatic relief and to rule out hemarthrosis 1, 2

Key Physical Examination Findings to Document

• Lateral joint line tenderness - localizes injury to lateral structures 3
• Varus stress testing - assesses LCL integrity at 0° and 30° of flexion 1
• Posterolateral drawer test - evaluates posterolateral corner involvement 1
• Range of motion limitations - documents functional impairment 3
• Popliteal fossa examination - characterizes posterior swelling 2

Acute Treatment Protocol (First 48-72 Hours)

PRICE Protocol Implementation

• Protection: Use crutches if unable to bear weight comfortably; avoid activities that reproduce pain 1, 5
• Rest: Relative rest, not complete immobilization (immobilization causes atrophy and delays recovery) 1, 6
• Ice: Apply through a wet towel for 10-minute periods every 2-3 hours while awake 6, 7
• Compression: Apply elastic wrap from toes to mid-thigh to control swelling 4
• Elevation: Keep leg elevated above heart level when resting 5

Pain and Inflammation Management

• NSAIDs are recommended to improve healing, speed recovery, and provide pain relief 1, 6
• Topical NSAIDs eliminate gastrointestinal hemorrhage risk if oral NSAIDs are contraindicated 6
• Cryotherapy provides effective acute pain relief based on available evidence 7

Diagnostic Imaging Strategy

When to Order Radiographs

• Immediate plain radiographs if unable to bear weight or significant bony tenderness (to rule out fracture or avulsion injury) 1, 3
• Standard knee series: AP, lateral, and merchant views 3

Advanced Imaging Considerations

• MRI is indicated if there is concern for multi-ligament injury, meniscal tear, or if symptoms persist beyond 6 weeks despite conservative treatment 3
• MRI should be obtained before considering surgical intervention 1
• Ultrasound can evaluate effusions and superficial structures if available 3

Definitive Treatment Based on Injury Severity

Grade I-II Lateral Ligament Injuries (Partial Tears)

• Conservative management is preferred with functional rehabilitation over immobilization 1
• Begin range of motion exercises as soon as tolerated (typically within 3-5 days) 1
• Progress to strengthening exercises focusing on quadriceps and hamstrings 1
• Functional knee braces are not recommended for routine use as they provide no clinical benefit 1

Grade III Injuries (Complete Tears) or Multi-Ligament Injuries

• Urgent orthopedic referral required for surgical evaluation 1
• Combined ligament injuries may require surgical reconstruction 1
• Delaying treatment beyond 3 months increases risk of additional cartilage and meniscal damage 1

Rehabilitation Protocol

Early Phase (Week 1-2)

• Manual joint mobilization combined with exercise therapy provides better outcomes than exercise alone 1
• Focus on restoring range of motion and reducing swelling 1
• Gentle isometric quadriceps and hamstring exercises 1

Progressive Phase (Week 3-6)

• Functional rehabilitation with motion restoration and strengthening exercises is preferred over immobilization 1
• Progress weight-bearing as tolerated 1
• Advance to closed-chain exercises (leg press, squats) 1

Return to Sport Criteria

• Functional hop testing should be used as one factor to determine readiness for return to basketball 1, 6
• Do not rely solely on time from injury; use objective functional measures 1
• Typical return to sport timeline: 6-12 weeks for isolated lateral ligament injuries 6

Critical Pitfalls to Avoid

• Do not delay orthopedic evaluation if there is concern for multi-ligament injury or neurovascular compromise 1
• Do not completely immobilize the knee, as this causes muscle atrophy and delays recovery 1, 6
• Do not clear for return to sport based solely on time elapsed; require functional testing 1
• Do not miss associated injuries such as meniscal tears, which are common with ligament injuries 1
• Do not ignore persistent swelling beyond 1-2 weeks, as this may indicate more significant structural damage requiring MRI 3