Management of Anterior Cruciate Ligament (ACL) Sprain

1. Patient Age and Activity Level

Patients < 30 years with high activity (Tegner 7‑10) should receive early ACL reconstruction to ensure knee stability and protect the menisci; this is a strong recommendation from the American Academy of Orthopaedic Surgeons. 1
Patients > 40 years with low‑to‑moderate activity (Tegner 3‑6) are best managed non‑operatively with supervised rehabilitation, activity modification, and self‑directed exercise programs; reconstruction is not routinely indicated. 1

Early reconstruction performed within 3 months of injury reduces subsequent cartilage and meniscal damage, which begins to accumulate after this window. 2

Patellar‑tendon (bone‑patellar‑bone) autograft is preferred to lower graft‑failure and infection rates. 2
Hamstring‑tendon autograft is an acceptable alternative when anterior knee or kneeling pain is a concern. 2

A supervised rehabilitation program emphasizing quadriceps and hamstring strengthening with both open‑ and closed‑kinetic‑chain exercises is recommended. 1
A self‑directed exercise regimen should be provided for long‑term maintenance of knee function. 1
Patients should modify activities to avoid pivoting, cutting, and jumping motions. 1
Functional knee bracing may be considered, although evidence supporting routine use is limited. 2

When technically feasible, meniscal repair is preferred over meniscectomy because meniscectomy markedly increases the risk of osteoarthritis (partial meniscectomy OR ≈ 1.9; total medial meniscectomy OR ≈ 3.1). 2
The presence of a repairable meniscal tear supports early ACL reconstruction to allow simultaneous meniscal repair. 2

Chondral damage raises the odds of developing osteoarthritis (OR ≈ 2.3) but does not alter the overall treatment algorithm for ACL sprain. 2
Minor osteoarthritic changes do not influence the decision between operative and non‑operative management. 1

Low‑grade MCL injuries heal adequately with conservative care and do not require surgical intervention. 1

Quadriceps strengthening using both open‑ and closed‑kinetic‑chain exercises is a core component of rehabilitation. 2
Progression should be criteria‑based rather than solely time‑based, with objective assessments of strength, stability, and functional performance guiding advancement. 2

Delaying reconstruction in young, active patients increases the likelihood of secondary meniscal injury and prolongs time to definitive surgery. 1
Performing unnecessary ACL reconstruction in older, sedentary patients who could succeed with rehabilitation should be avoided. 1
Relying on time alone for return‑to‑sport decisions (instead of functional criteria) raises the risk of reinjury. 2
Choosing meniscectomy when meniscal repair is feasible significantly elevates the risk of subsequent osteoarthritis. 2