The anterior cruciate ligament (ACL) stabilises the knee during twisting movements. Tears typically happen during sport (such as football, badminton, basketball, or a slip on a wet floor), with a popping sensation, immediate swelling and a feeling that the knee 'gave way'.
The first step after any suspected ACL injury is a clinical examination, usually followed by an MRI to confirm the tear and check the meniscus and other ligaments. Early physiotherapy focuses on reducing swelling and restoring motion.
Not every ACL tear needs surgery. Lower-demand, older patients can function well with a strong physiotherapy programme. Younger or active patients whose knees keep giving way usually benefit from arthroscopic reconstruction, where a tendon graft rebuilds the ligament.
Recovery after reconstruction is staged: walking within days, strengthening over weeks, and a return to sport typically after 9–12 months of guided rehabilitation. Skipping the rehab stages is the most common cause of poor outcomes.
Medical Disclaimer: This article provides general orthopaedic education and is not a substitute for clinical diagnosis. If your symptoms match anything described here, a thorough examination is the safest next step.