The Menisci are 2 semicircular cartilaginous structures (meniscus) in the knee that are commonly injured. There are numerous factors to take into account when considering meniscus repair, find out more about the process below.
Meniscus Functions
The meniscus has several functions including:
- Increasing congruity of the knee joint.
- Decreasing the force in the knee joint.
- Aiding in the circulation of nourishing synovial fluid.
- Augmenting stability of the knee with the ligaments.
The menisci are prone to damage with twisting and pivoting sports and are often associated with other injuries of the ligaments within the knee.
Meniscus Damage Symptoms
The patient will experience one or more of the following symptoms:
- Pain and swelling of the knee.
- Locking (inability to fully straighten the knee with mechanical block).
- Pseudo-Instability (the feeling that the knee is going to give way without it doing so).
- Clicking – painful or otherwise.
There are a number of different tear types. The tears are classified according to their morphology, and different tear types have a different propensity for healing thus making some tears more amenable to repair than others.
The removal of the meniscus has long been known to be associated with early-onset arthritis of the knee.
Meniscus Repair or Removal
Fairbank (a radiologist) in 1948, showed that removing the meniscus caused arthritis. It is only since the ubiquity of arthroscopic surgery (“keyhole” knee surgery) that routine meniscal repairs have been done.
There are a number of factors that determine whether a meniscal tear is repairable or not. These include:
- Position of the tear – peripheral tears in the Red/Red zone are more likely to heal due to better blood supply than tears in the White/White zone where blood supply is almost absent (Fig 3).
- The time between injury and diagnosis – longer is worse for success.
- Younger people tend to heal faster and thus age often determines success.
- Presence of arthritis greatly diminishes the chance of successful repair.
- Concurrent ligament repair improves the chance of successful repair.
Meniscus Repair, Knee Surgery
Repair of the meniscus is accomplished by many varied surgical techniques and tricks. In essence the torn fragments are reduced to their native position and sutured in place with an extremely durable suture. The hope is that the meniscus heals, and the suture becomes redundant.
Repair of the meniscus is always preferable to resection (removal of the torn parts of the meniscus leaving the rest intact). Due to the above factors, sometimes the risk of re-tear is substantial, and the resection is done at the beginning. If resection is necessary, the smallest volume of meniscal tissue possible is removed, preserving as much normal meniscus as possible.
Even in the best hands, the failure rate of meniscal repair is in the order of 15%. If failure does occur, a re-repair could be tried or the torn meniscus partially removed.
