Medial Meniscus Syndrome

Medial Meniscus Syndrome

Of the menisci within the knee, it is the medial that is more easily injured. Differences in the anatomical attachments of the medial meniscus compared to the lateral, mean that the medial meniscus becomes distorted during combined flexion and rotation movements in a manner not experienced on the lateral side.

Mechanism of Injury




Locking: The inability to extend the affected knee to the same extent as the contra-lateral side. Crucially, this is due to a mechanical block and whilst pain may be a feature, it is not the sole reason the knee is unable to extend. This presentation is caused by a bucket handle tear (an unstable vertical longitudinal tear) prolapsing out of position creating the mechanical block to movement.

Pain: This is characteristically intermittent in nature and associated with activities such as stair climbing or running. Patients will often complain of an inability to squat fully. Patients will also exhibit tenderness along the joint line of the affected knee.

Swelling: In large peripheral tears, the injury may be associated with a post-traumatic effusion. More commonly, the irritation caused by the damaged meniscus causes recurrent effusions associated with exacerbation of the symptoms. Another form of swelling is the localized meniscal cyst caused by a complex meniscal tear acting as a flap valve to synovial fluid leading to the gradual formation of a parameniscal cyst that may be apparent clinically.



Very rarely indicated, except when confirming the presence of a meniscal cyst. MRI is the preferred investigation for this, as it will confirm the presence of a meniscal tear.


Not indicated for the assessment of knee pain.




In cases where a meniscal injury is associated with degenerative change within the knee, it may be difficult to ascertain which pathology is causing the majority of the symptoms. In such cases, an unwise intervention may lead to a perceived deterioration in knee function and the torn meniscus may be best left in situ.

Arthroscopic Excision

This is the most commonly performed treatment option and provides an excellent, long term symptom relief for the majority of patients. Although the majority of patients will experience improvement within a few weeks of surgery, some may require longer periods due to extensive quadriceps atrophy or other intra-articular pathology.

Arthroscopic Repair

In certain specific cases, the meniscus may be able to be repaired. This is usually restricted to those cases where a fresh, peripheral tear is identified at arthroscopy in a young patient. The limited application for meniscal repair is due to the poor blood supply found within the majority of the meniscus meaning only the outer 25% has viable healing potential. It is an important consideration for many patients that a meniscal repair will necessitate a much prolonged period of rehabilitation when compared to a simple excision.


The majority of the literature regarding prognosis following meniscal excision dates from the pre-arthroscopic era of total open meniscectomy. As such, there is a commonly held perception that excision results in arthritis. This is overly pessimistic. Having a meniscal tear is a significant injury to the knee. Ongoing mechanical symptoms indicate ongoing damage to the chondral surfaces of the joint. If an arthroscopic excision is performed before an extensive chondral injury has been sustained, many patients do not develop problematic osteoarthritis and will experience long term symptom relief.