Background – We are born with 3 layers of protective cartilage in our knees. Each bone is covered with a protective cartilage layer providing a friction-free surface for the joint to glide and also aiding in joint lubrication (layers 1 and 2). The third layer is the more mobile meniscus which acts as a shock absorber and helps to spread load over the knee joint. These layers have only a limited ability to heal themselves when damaged. Once gone, which may be due to injury, wear or surgical trimming (known as debridement or meniscectomy), then painful arthritis may result. For this reason it is important to try to save these layers and facilitate healing whenever possible. Advances in technology as well as improved techniques mean we now possess legitimate and evidence-based options to try to achieve our goal – saving our knees and delaying the need for more traditional treatments such as knee replacement surgery.
Meniscal Injury: The menisci are commonly damaged by a twisting injury under load or a sudden loading of the knee. This can occur at any age. Sometimes the attachment of the meniscus is completely torn away which can cause significant pain and discomfort for a number of weeks – these root tears are serious injuries that should be evaluated early.
As we get older the menisci weaken due to natural degeneration which can make them susceptible to tears from less traumatic incidents – known as degenerate meniscal tears.
Signs of Meniscal Injury:
Acute Traumatic tears – Sometimes you will feel a pop at the time of injury. It is common to be able to continue to walk afterwards. Swelling usually develops after a number of hours and often not until the next day. Larger tears can cause the knee to get stuck in a bent position (locking). Clicking and catching may cause the knee to give way.
Degenerative tears – Degenerative meniscal tears may cause very similar signs and symptoms but without the initial obvious moment of injury. Pain on one side of the knee joint may be the only real sign.
Diagnosis: A thorough clinical examination along with an Xray and MRI scan will show the extent of damage and the presence of other injuries which may also be present. This will allow proper planning and an informed discussion about the treatment options.
Treatment Options: This depends on many factors which include the type and location of tear, the degree of symptoms and certain important patient-related factors.
Non-operative management: Some tears, and particularly degenerative type tears, respond well to a period of recovery with dedicated physiotherapy to assist with improved strength and control around the knee. Pain will often settle completely. Should mechanical symptoms of clicking, catching or locking fail to improve then surgery may be indicated. For traumatic tears the tear pattern is important.
We know from numerous scientific papers that, whenever possible, a meniscus should be repaired and not trimmed or removed. It plays a vital role in spreading load and, therefore, protecting the joint surface cartilage that lines the femur and tibia. I will make every effort to repair a damaged meniscus.
An athroscopic photograph of a normal Meniscus
In this case a Meniscus tear is seen and examined with a probe
Unfortunately it is not always possible to repair a meniscus. A successful repair depends on multiple factors that include the type of tear, position of the tear, chronicity of the tear (how long it has been torn) and the quality of the meniscus tissue. Research has shown that tears in central regions of the meniscus, where the blood supply is poor, carry a low chance of a successful repair. Older meniscal tears become frayed with time and it is therefore vital to seek advice soon after a knee injury in order to pick these tears up before they become irreparable. In older patients the quality of meniscal tissue can also make a repair less successful – the meniscus has to be able to securely hold the stitches. Conversely many tear patterns are very amenable to repair and this should ideally be performed as soon as possible – expedited referral to a knee specialist who has a proven track record in meniscal repair is therefore paramount.