What is the treatment for an Anterior Cruciate Ligament (ACL) sprain?

Treatment of ACL Sprain

ACL sprains should be managed based on injury severity, patient activity level, and age, with surgical reconstruction strongly preferred within 3 months for complete tears to prevent additional meniscal and cartilage damage, while partial tears may be treated conservatively with structured rehabilitation. 1

Initial Assessment and Acute Management

• Aspirate painful, tense knee effusions for symptomatic relief in the acute setting 1
• Apply PRICE protocol (Protection, Rest, Ice, Compression, Elevation) immediately after injury 2
• Obtain radiographs to exclude fractures or bony avulsions if clinically indicated 2
• Measure baseline range of motion (ROM) and quadriceps strength, as preoperative extension deficits and quadriceps weakness >20% significantly worsen 2-year outcomes 1

Treatment Algorithm by Injury Severity

Partial ACL Tears (Grade I-II Sprains)

• Conservative management with structured rehabilitation is the initial approach for incomplete tears 3
• Refer to physical therapy for prehabilitation, which improves self-reported knee function up to 2 years post-injury 1
• Monitor for functional instability; proceed to reconstruction only if instability develops 3

Complete ACL Tears (Grade III)

Surgical reconstruction is strongly recommended for complete tears, particularly in younger and more active patients, to reduce risk of future meniscus pathology and improve long-term pain and function. 1

Surgical Timing

• Early reconstruction within 3 months is strongly preferred because risk of additional cartilage and meniscal injury increases after this timeframe 1
• This is a strong recommendation that should be followed unless compelling rationale exists for delay 1

Surgical Technique Decisions

Reconstruction vs. Repair:

• ACL reconstruction is strongly preferred over repair due to lower risk of revision surgery 1
• Repair techniques have historically shown poor outcomes 4, 5

Single-Bundle vs. Double-Bundle:

• Either single-bundle or double-bundle reconstruction can be used as outcomes are similar (strong recommendation) 1
• Both techniques adequately restore knee stability 6

Graft Selection:

• For skeletally mature patients, bone-patellar tendon-bone (BTB) autograft reduces graft failure and infection risk, while hamstring autograft reduces anterior knee pain and kneeling pain 1
• Consider anterolateral ligament (ALL) reconstruction or lateral extra-articular tenodesis (LET) when using hamstring autograft to reduce graft failure and improve short-term function 1

Concomitant MCL Injury

When ACL and MCL tears occur together, treat the MCL non-surgically while reconstructing the ACL surgically—this results in good patient outcomes. 1, 2

• MCL surgical treatment may be considered only in select cases with severe instability 1, 2
• This approach applies even to complete grade III MCL tears 2

Rehabilitation Protocol

Early Phase (0-4 Weeks Post-Surgery)

• Immediate weight-bearing is recommended if correct gait pattern is maintained without pain, effusion, or temperature increase 1
• Immediate weight-bearing decreases anterior knee pain without affecting knee laxity 1
• Begin isometric quadriceps exercises in week 1 when pain-free to reactivate muscles 1
• Consider electrostimulation combined with isometric exercises for improving quadriceps voluntary contraction in first 2 months 1
• Apply cryotherapy in the first postoperative week to reduce pain 1

Intermediate Phase (4-12 Weeks)

• Start closed kinetic chain (CKC) exercises from week 2 1
• For BTB grafts: Begin open kinetic chain (OKC) exercises at week 4 in restricted ROM (90-45°) with added resistance 1
• For hamstring grafts: Begin OKC exercises at week 4 in restricted ROM (90-45°) but without extra weight for first 12 weeks to prevent graft elongation 1
• Progressively increase ROM: 90-30° (week 5), 90-20° (week 6), 90-10° (week 7), full ROM (week 8) 1
• Add neuromuscular/motor control training to strength training to optimize outcomes and reduce reinjury risk 1

Advanced Phase (3-12 Months)

• Continue rehabilitation for 9-12 months depending on return-to-work or return-to-sport goals 1
• Achieve full ROM with no pain or swelling 1
• Target >90% limb symmetry index (LSI) for quadriceps and hamstring strength, countermovement jump, and drop jump 1
• For field sport athletes, achieve reactive strength index >1.3 for double leg and >0.5 for single leg 1
• Restore >90% symmetry of ground reaction forces and knee biomechanics during high-speed running 1

Return to Sport Criteria

Use functional evaluation (hop tests, strength testing) as one factor to determine return to sport rather than time-based protocols alone. 1

Minimum criteria for professional athletes:

• No pain or swelling with stable knee examination 1
• Full ROM restored 1
• Isokinetic quadriceps and hamstring peak torque at 60°/s displaying 100% symmetry for high-demand pivoting sports 1
• Normalized subjective knee function using patient-reported outcomes (IKDC, ACL-RSI, Tampa Scale) 1
• Complete sports-specific training program 1

What NOT to Do

• Do not use functional knee braces routinely after isolated primary ACL reconstruction—they provide no clinical benefit 1
• Do not use prophylactic knee braces to prevent ACL injury—they are not effective 1, 2
• Do not delay reconstruction beyond 3 months for complete tears without compelling reason, as meniscal and cartilage damage risk increases 1

Prevention for At-Risk Athletes

• Implement ACL injury prevention training programs for athletes in high-risk sports to reduce primary ACL injury risk 1
• These neuromuscular training programs have moderate evidence supporting their use 1