Describe Knee Ligament & Meniscal Injuries in detail.

Definition & Anatomy

The knee is stabilised by four main ligaments — the anterior and posterior cruciate ligaments (ACL, PCL) and the medial and lateral collateral ligaments (MCL, LCL) — and cushioned by the medial and lateral menisci. Sports and twisting injuries commonly damage these structures, causing pain, instability and, in the long term, osteoarthritis.

Anterior Cruciate Ligament (acl) Injury

The ACL prevents anterior translation and rotation of the tibia. It is typically torn by a non-contact twisting/pivoting injury (deceleration with the foot planted), often in sport. The patient may feel or hear a ‘pop’, develops a rapid haemarthrosis (swelling within hours), and complains of the knee giving way on pivoting. Diagnosis is clinical (Lachman’s test — the most sensitive — and the anterior drawer and pivot-shift tests) confirmed by MRI.

Meniscal Injuries

The menisci are torn by a twisting force on a flexed, weight-bearing knee (younger patients) or by degeneration (older patients). Features include joint-line pain and tenderness, swelling that develops over a day, and mechanical symptoms — clicking, catching or ‘locking’ (a displaced bucket-handle fragment blocking full extension). McMurray’s test reproduces pain/click; MRI confirms.

Management

Acl:

• not all tears need surgery.
• Physiotherapy (quadriceps/hamstring rehabilitation) suits lower-demand patients and copers
• arthroscopic ACL reconstruction (with a tendon graft) is offered to young, active patients or those with instability, followed by prolonged rehabilitation.
• Meniscus: a small stable or degenerate tear is treated conservatively
• a repairable peripheral (vascular ‘red zone’) tear is repaired to preserve the meniscus, while an irreparable symptomatic tear is treated by limited arthroscopic meniscectomy (preserving as much meniscus as possible).
• Collateral ligament injuries usually heal with bracing.

Long-term Consequences & the ‘unhappy Triad’

A severe valgus-and-rotation injury of the knee can damage three structures together — the ACL, the medial collateral ligament and the medial (or lateral) meniscus — the combination classically termed O’Donoghue’s ‘unhappy triad’. Whatever the pattern, the long-term importance of these injuries lies in the risk of secondary osteoarthritis: an ACL-deficient, unstable knee and, especially, a meniscus-deficient knee wear out prematurely, which is the rationale for restoring stability and for preserving as much meniscus as possible rather than excising it wholesale.

Immediate haemarthrosis suggests ACL tear.

• ACL/PCL + MCL/LCL stabilise the knee; menisci share load & absorb shock.
• ACL tear: twisting/pivot injury, ‘pop’, rapid haemarthrosis, giving way; Lachman’s most sensitive.
• Meniscal tear: joint-line pain, delayed swelling, clicking/locking; McMurray’s test.
• ACL: physio for copers, reconstruction for active/unstable knees.
• Meniscus: repair peripheral (red-zone) tears, preserve meniscus; a locked knee needs prompt arthroscopy.