Overview
- Main restraint to anterior tibial translation, also aids rotational stability
- Noncontact pivot, a pop, rapid haemarthrosis, then giving way
- Lachman most sensitive, pivot shift most specific
- MRI confirms the tear and meniscal and chondral injury
- Rehabilitation suits many, reconstruction for persisting instability
- Young pivoting athletes do better with autograft reconstruction
Western Health Orthopaedic Registrar presentation -ACL Management: Operative vs Non-operative by Dr Amy Gibbens
Anatomy
- Lateral intercondylar ridge marks the anterior femoral footprint limit
- Anteromedial bundle is tight in flexion and resists anterior tibial translation
- Posterolateral bundle, tight in extension, controls rotation
Clinical Features
- Non-contact pivot, a pop and rapid haemarthrosis
- Lachman is most sensitive, pivot shift most specific
- Instrumented side to side difference over 3 mm
- Bone bruising of the lateral femoral condyle and posterolateral tibial plateau
- Segond fracture is pathognomonic
- Lateral meniscal tears acutely, medial tears in chronic deficiency
- Ramp lesions of the medial meniscus posterior horn
Management
- KANON, rehabilitation with optional delayed surgery equalled early reconstruction
- COMPARE, a small advantage for early reconstruction below clinical relevance
- ACL SNNAP, reconstruction superior to rehabilitation in chronic deficiency
- Reconstruct for recurrent instability, pivoting sport, reparable meniscal tears and multiligament injury
- Patellar tendon graft gives bone healing but anterior knee pain and patellar fracture risk
- Hamstring graft under 8 mm fails more
- STABILITY, lateral extra-articular tenodesis with hamstring graft reduced failure in young high-risk patients
- Operate once swelling settles and full extension returns
Prognosis
- Return to sport after 9 months is associated with fewer reinjuries
- Criteria include quadriceps and hop symmetry above 90 percent and ACL-RSI readiness
- Young athletes have a high risk of graft and contralateral ACL rupture
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.