Meniscal Tear

Background

The meniscus provides important functions for the knee, including sharing load transmission across the joint, shock absorption, and joint nutrition (Heckmann JOSPT 36:795 2006). Loss of the meniscus, such as in meniscectomized knees, causes predictable changes to the joint. In 1948, Fairbank described three radiological changes, now know as Fairbank's changes. These include: 1. formation of a ride on the femoral condyle; 2. flattening of the femoral condyle and; 3. Joint space narrowing. Observation of these degenerative changes led surgeons to preserve as much meniscal tissue as possible after injury.


Causes


Diagnosis


Treatment

Injuries to the meniscus are treated either conservatively, with a full or partial meniscectomy, debridement, repair, or allograft transplantation. Tears located along the periphery, or red zone, may respond to non-operative management due presence of sufficient vascularity for healing (201). Non-operative rehabilitation is focused on contolling swelling, maintaining or improving range of motion and strength. The patient should avoid any unnecesary squatting, pivoting, running, or jumping. Indications for surgery include the knee giving way or locking, persistant swelling or inability to regain ROM or strength. If surgery is performed, efforts are made to preserve as much meniscal tissue as possible in order to preserve the joint. A tear that exists in the middle two thirds of the meniscus in generally excised. There are no post-operative precautions following a partial meniscectomy. Typical recovery time is 2-6 weeks.
Tears located in the periphery of the meniscus are usually repaired. Limiting shear forces is very important after a repair and therefore weight bearing will be limited to allow sufficient healing. Given a satisfactory repair, the physician may allow the patient to weight bear with the brace locked in full extension. Closed chain squats will be limited in the first 4-8 weeks to prevent loading combined with shearing forces.
A meniscal allograft transplant is an option to preserve normal shock absorption in those who have an irrepairable meniscus, osteoarthritis, or have had a previous total meniscectomy.

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