Patellar instability occurs when the patella does not remain in its groove, resulting in a partial or complete dislocation.
Pain from the patella and patellofemoral joint are often categorised as Anterior Knee Pain
Instability can occur after an accident or trauma to the knee and is a relatively common injury in contact sports. Injuries to the knee are often complex, involving several structures. It is important to have the knee fully assessed to ensure that any damage is identified. Imaging can include Xrays to assess the bones and ultrasound or MRI to view the soft tissues including tendons, ligaments, the joint capsule and the meniscii.
Following a dislocation of the patella which hasn’t involved any other structures, rest and physiotherapy can be sufficient to prevent further problems.
If other structures have been involved, dislocations keep occurring or if the knee remains painful, then surgery may be required. Detailed imaging of the knee can show injury to the tendons and/or other structures which may require surgical repair.
Congenital / development instability
The exact shape and size of the patella and the trochlea groove on the femur can effect patella stability. If the groove which the patella articulates with is shallow or does not match the shape of the patella, the patella can be prone to partial or full dislocations.
The patella can be pulled to the side, away from the correct location, either through tightness in the surrounding tissues or through the quadriceps tendon inserting too close to the side of the patella. These problems can also lead to instability.
Treatment for patellar instability
If the patella is being pulled to the side, physiotherapy can sometimes be enough to relieve the pressure on the tendon.
If a course of physiotherapy is not suitable, does not relieve pain or prevent further instability, surgery may be required. This can involve the release of tissues to relieve tension and allow the patella to move back to the correct position.
In severe cases involving the shape of the bones and recurrent dislocations, surgery to the patella or femur may be required. This can involve changing the shape and resurfacing the joint surfaces.
Your Consultant will discuss the most suitable treatment plan for your individual condition.