What is the treatment for an anterior cruciate ligament (ACL) sprain?

Treatment of ACL Sprain

For patients under 30 years old with high activity levels, early ACL reconstruction is the preferred treatment to provide knee stability and protect the menisci from subsequent injuries, while older, less active patients (particularly over 40) should be managed with supervised rehabilitation, activity modification, and self-directed exercise programs without reconstruction. 1, 2

Treatment Algorithm Based on Patient Characteristics

Young, Active Patients (<30 years, Tegner level 7-10)

Surgical reconstruction is strongly recommended as the first-line treatment for this population:

• Age under 25 years predicts 88.9% failure rate of nonoperative treatment, with these patients ultimately requiring surgery anyway 3
• High activity levels (Tegner 7-10) result in 82.8% failure of conservative management 3
• Delaying surgery increases risk: patients who fail nonoperative treatment wait an average of 6.2 months versus 2.2 months for direct reconstruction, and develop new meniscal injuries 5.6 times more frequently (17.4% vs 3.1%) 3
• Early reconstruction (within 3 months) prevents additional cartilage and meniscus damage that begins accumulating after this timeframe 2

Graft Selection for Young Patients

• Patellar tendon (BTB) autograft is favored to reduce graft failure and infection risk 2
• Hamstring tendon autograft is an alternative if anterior knee pain or kneeling pain is a concern 2
• Avoid allograft in patients under 40 years due to inferior outcomes 4

Older, Lower Activity Patients (>40 years, Tegner level 3-6)

Nonoperative management is appropriate and should include:

• Supervised rehabilitation program focusing on quadriceps and hamstring strengthening using both open and closed kinetic chain exercises 1, 2
• Self-directed exercise program for long-term maintenance 1
• Activity modification to avoid pivoting, cutting, and jumping activities 1
• Functional knee bracing may be considered though evidence for routine use is limited 2

Success rates for this approach: 67.1% of patients over 40 years and 58.1% of patients with Tegner levels 3-6 avoid surgery with conservative management 3

Middle-Age Patients (25-40 years, Moderate Activity)

Treatment decision requires careful assessment:

• 44% of patients in this age group succeed with nonoperative treatment 3
• Consider reconstruction if: functional instability develops, patient desires return to cutting/pivoting sports, or physically demanding occupation 4
• Trial of supervised rehabilitation for 2-4 months is reasonable, with surgery if instability persists 5

Concomitant Injuries Influence Treatment

Meniscal Tears

• Meniscal repair should be prioritized over meniscectomy whenever technically possible, as meniscectomy dramatically increases osteoarthritis risk (OR=1.87 for partial, OR=3.14 for total medial meniscectomy) 2
• Presence of repairable meniscal tears favors early reconstruction to enable concurrent repair 2

Chondral Lesions

• Chondral damage increases osteoarthritis risk (OR=2.31) but does not change treatment algorithm 2
• Minor osteoarthritic changes do not influence treatment decisions 1, 2

MCL Sprains

• Low-grade MCL injuries heal well with conservative management and do not require surgical intervention 1

Rehabilitation Protocol (Both Operative and Nonoperative)

Immediate mobilization and weight-bearing are standard:

• Range of motion exercises begin immediately 6
• Weight-bearing encouraged within first week 6
• Quadriceps strengthening is critical using both open and closed kinetic chain exercises 2
• Criteria-based progression rather than time-based alone: assess objective strength, stability, and functional parameters 2

Return to Sport Timeline (Post-Reconstruction)

• Light running at 2-3 months 6
• Contact sports with cutting/jumping at minimum 6 months, but only after meeting objective criteria 6
• Do not rely solely on time: require functional stability, adequate muscle strength, and sport-specific performance testing 6, 5

Common Pitfalls to Avoid

• Delaying reconstruction in young, active patients leads to secondary meniscal injuries and longer time to surgery 3
• Performing unnecessary surgery in older, sedentary patients who would succeed with rehabilitation 1
• Allowing time-based rather than criteria-based return to sport, which increases reinjury risk 2
• Performing meniscectomy when repair is feasible, dramatically increasing osteoarthritis risk 2
• Ignoring patient activity level and age when making treatment decisions 3