Meniscus Tears
The knee meniscus is a small but important fibrocartilage that sits on top of the tibia and mostly acts to absorb the everyday force that goes through the knee for example with walking and running. In fact there are two menisci per knee – one on the medial (inner) side and one of the lateral (outer side). Their other very important roles include to contribute to the stability of the knee as well as to distribute synovial fluid (the natural lubricant within joints).
As the menisci are subject to significant forces they can develop tears within them either suddenly with an acute knee injury or slowly over time. Acute meniscus injuries can occur insolation or they can be associated with other ligament injuries eg ACL, PCL, collateral ligaments or any combination of these. Non acute meniscal tears are often called degenerative as they are usually seen when there has been “wear and tear” within the knee joint and the meniscus tear is a part of that. The different type of meniscus tears can occur with different configurations. Horizontal meniscus tears are often seen with the degenerate type, while vertical and radial tears are usually present in the acute injury type. Tears involving the root (attachment of the meniscus to the tibia) of the meniscus can be either degenerative or acute. Both are important as they have been associated with progression to arthritis within the affected knee if left untreated.
Treatment depends on many factors including if the tear is acute or chronic, horizontal or vertical (or radial), associated with ligament injury and whether they are displaced (moved out of their usual position) or not. The majority of meniscus tears are the degenerative horizontal type which should be managed non-operatively where possible. Treatments include oral analgesia/anti-inflammatories, corticosteroid injection (to help reduce inflammation), physiotherapy/hydrotherapy, knee braces and heat or cold packs. If the meniscus tear is associated with knee arthritis, then optimisation of knee joint health should be employed.
When non operative treatment methods have been exhausted then surgical management with arthroscopic surgery (key hole) may be beneficial. Often this involves trimming the affected meniscus back to a smooth and stable base. When there has been an acute meniscus injury with displacement, repair of the meniscus should be undertaken as soon as possible.
The operation is performed arthroscopically and the procedure involves reducing the displaced meniscus back to its original position and suturing it in place with special meniscus stitches. The outcome of meniscal repair is enhanced when there is optimal blood supply to the meniscus being fixed. This occurs when the patient is younger, the time to surgery is reduced and where the injury location is around the very periphery of the meniscus in a vertical orientation or at the root of the meniscus. Due to the function of the meniscus it is important repair the meniscus as much as possible. Occasionally when the meniscus is too badly torn or where healing is thought to be unlikely to occur, the meniscus will need to be trimmed back to a stable base conserving as much of the meniscus as possible. Meniscus repair also relies on a stable knee joint, and as such if there has been any associated knee ligament injury, the aim is to treat these ligament injuries at the same time to stabilise the knee.