What is the initial management for an 18-year-old with a left knee injury?

Initial Management of Left Knee Injury in an 18-Year-Old

For an 18-year-old with an acute left knee injury, begin with clinical assessment using the Ottawa Knee Rule to determine if radiographs are needed, followed by functional support (bracing), early mobilization, and structured exercise therapy rather than immobilization. 1

Initial Clinical Assessment and Imaging Decision

Apply the Ottawa Knee Rule to determine imaging necessity. 1 Obtain knee radiographs (minimum anteroposterior and lateral views) if the patient meets ANY of the following criteria:

• Age 55 years or older (not applicable here) 1
• Palpable tenderness over the head of the fibula 1
• Isolated patellar tenderness 1
• Cannot flex the knee to 90° 1
• Cannot bear weight immediately following injury 1
• Cannot walk in the emergency room (after taking 4 steps) 1

Do NOT apply clinical decision rules and obtain radiographs regardless if there is: gross deformity, palpable mass, penetrating injury, prosthetic hardware, unreliable history due to multiple injuries, altered mental status (head injury, drug/alcohol use), or neuropathy. 1

The Ottawa Knee Rule has demonstrated 100% sensitivity for detecting knee fractures while reducing unnecessary radiographs by 35%. 1

Acute Phase Management (First 2-3 Weeks)

Functional Support Over Immobilization

Use functional support (ankle brace adapted for knee or knee brace) for 4-6 weeks rather than rigid immobilization. 1 While the evidence cited is from ankle injuries, the principle of functional support applies to knee ligament injuries as well. 2, 3

• If immobilization is needed for severe pain or swelling control, limit it to a maximum of 10 days, then transition to functional treatment. 1
• For patellar dislocation specifically, use a short period of knee bracing in extension with progression to weight-bearing as tolerated. 2
• Most grade I and II ligament sprains (partial tears) and isolated grade III posterior cruciate ligament tears can be treated non-operatively. 3

Pain Management

Start with acetaminophen up to 4,000 mg/day as first-line analgesic. 1 Acetaminophen is equally effective as NSAIDs for pain control (MD 1.80,95% CI −1.42 to 5.02) with fewer side effects. 1

If acetaminophen is insufficient, use NSAIDs judiciously for SHORT-TERM use only (a few days). 4

• NSAIDs may delay natural healing by suppressing inflammation necessary for tissue recovery. 1
• NSAIDs are NOT recommended for completed fractures, stress fractures at risk of nonunion, or chronic muscle injury. 4
• NSAIDs may be more appropriate for acute ligament sprains, muscle strains, and tendinitis, but keep duration as short as possible. 4

Avoid opioid analgesics as they provide equal pain relief to other options but cause significantly more side effects. 1

Rehabilitation Phase (After Initial 2-3 Weeks)

Early Exercise Therapy

Initiate exercise therapy early (within 2-3 weeks) to reduce risk of recurrent injuries and functional instability. 1 Exercise programs should include:

• Neuromuscular and proprioceptive exercises 1
• Hamstring and quadriceps strengthening (isometric, isotonic, isokinetic, and eccentric exercises) 3
• Gradual progression from 40-45 degrees flexion mobilization to full range of motion 3

Early exercise therapy reduces the prevalence of recurrent injuries (10 RCTs, n=1284) and functional instability (3 RCTs, n=174), and is associated with quicker recovery. 1

Manual Therapy Adjunct

Consider manual joint mobilization to increase dorsiflexion ROM and decrease pain (12 RCTs, n=427). 1 Manual therapy should be combined with exercise therapy for optimal outcomes. 1

Return to Activity Timeline

• Weight-bearing: Progress to tolerance after initial pain control 2, 3
• Jogging: Typically allowed 3-6 months post-injury 3
• Full competitive sports: Generally 6-12 months post-injury 3
• Functional knee brace: May be used during return-to-sport phase for extra protection 3

Critical Pitfalls to Avoid

Do NOT use prolonged immobilization (>10 days) as it leads to cartilage, bone, muscle, tendon, and ligament deterioration without improving outcomes. 1, 3

Do NOT delay exercise therapy as early mobilization with controlled stress enhances collagen fiber orientation along stress lines of healing ligaments. 3

Motivation is crucial for successful rehabilitation and is often more important than the specific methodology used. 3 Encourage and support the patient throughout the 6-12 month recovery process. 3

When to Consider Surgical Referral

Refer for orthopedic evaluation if: grade III ACL tear in a young athlete planning to return to pivoting sports, certain meniscal tears requiring repair, extensor mechanism disruptions, or combined ligamentous injuries. 2, 5 Most isolated medial collateral ligament, lateral collateral ligament, and posterior cruciate ligament injuries can be managed non-operatively. 2, 5