Some patients have an inherently unstable kneecap either because of generally flexible joints, the shape of the kneecap and the groove it sits in or a combination of the two. Other patients sustain an injury causing their kneecap to become unstable. The condition is more common in females and repeated episodes can cause the kneecap or the thighbone to become damaged leading to premature wear of the joint.
Symptoms of Patella Instability
Often the problem first starts as a teenager. The kneecap dislocates, usually during sports or whilst dancing and the leg gives way. The episode is usually painful and the knee may become swollen. Often the kneecap spontaneously slips back into place as the knee straightens out but sometimes a trip to hospital is required to have it put back under sedation.
Treatment of Patella Instability
The first line treatment for almost all cases is physiotherapy. The aim is to strengthen the muscles around the knee, particularly those on the inner side of the knee (the VMO muscles) to protect the kneecap. Taping or bracing the kneecap can be used to partially stabilise the knee until the muscles strengthen but shouldn’t be relied on as a long-term treatment.
If instability episodes recur despite physiotherapy treatment then surgery can be considered. There are three types of surgery aimed at either tightening up the soft tissues around the knee, altering the line of pull of the muscles or altering the shape of the bones. All aim to improve the stability and which is chosen depends very much on the cause of the original instability. The operation is done under a general anaesthetic and a single night in hospital is usually required. Following surgery, a brace is worn on the knee for six weeks and several months of physiotherapy are required before hopefully returning to all activities. If the kneecap or thighbone have been damaged due to recurrent dislocations some on-going pain may be experienced even if the kneecap remains stable.