Patellar dislocations are common injuries that are seen at Advanced Orthopaedic Specialists. A patellar dislocation is whenever the kneecap (patella) dislocates from the femur (trochlea). This is relatively common in teenage athletes. It most commonly occurs with a twisting mechanism with the foot planted in one direction and the body turned in the opposite direction. The athlete will feel their kneecap slide out of the joint. Most commonly, the kneecap will relocate on its own; however, sometimes, it requires a trainer or physician to relocate it.
The patellofemoral joint is a convex-concave articulation. Some patients have less of a concavity on the thigh, which predisposes them to a patellar dislocation. The good news is that the majority of patellar dislocations are treated non-operatively. If a patient is seen at Advanced Orthopaedic Specialists with a patellar dislocation, we initially treat them with a brace, aggressive physical therapy, and anti-inflammatories. Once the swelling and pain has subsided, we will release them to return to sports. This can take anywhere from one to four weeks. The majority of patients who experience patellar dislocation will have no further problems as long as they keep their quadriceps strong and their muscles stretched.
If a patient experiences recurrent dislocation, this prompts us to investigate this further with MRIs. The MRI can show an injury to the main stabilizer of the patellofemoral joint, which is the medial patellofemoral ligament. The more times the patellar dislocates, the more likely there is injury to the medial patellofemoral ligament. This is the main stabilizer of the patellofemoral joint and if the patella continues to dislocate, this would be an indication for surgery. In the past, patellofemoral reconstruction surgeries were very unsuccessful; however, with the advent of reconstruction of the medial patellofemoral ligament, there is approximately a 95% success rate of no further dislocations and return to full activity.
Sometimes, when the patella dislocates, it can injure the cartilage behind the patella or on the adjacent femur. This can sometimes lead to small cracks in the cartilage or even loose cartilage pieces that float within the knee. If this happens the patient would experience pain and swelling and would require an arthroscopy to smooth down the cracks or retrieve any loose pieces.
The good news with the patellar dislocations is that the majority (greater than 90%) are treated with aggressive therapy, anti-inflammatories, and bracing. However, if this fails, the patient can expect a full return with either an arthroscopy to retrieve the loose pieces or a formal reconstruction. If you had episodes of patellar dislocations, call Advanced Orthopaedic Specialists.
Written by Dr. Christopher Arnold, M.D.