An excessive Q-angle can cause problems with tracking of the patella (kneecap). The Q-angle is the angle formed by the patellar tendon as it attaches to the knee joint. There is a groove underneath the patella that helps it slide up and down correctly over the femur (thighbone).
Anything that disrupts the normal tracking can wear down the cartilage and bone. An excessive Q-angle can have this effect. Realignment procedures can be done on the knee. A wedge- or pie-shaped piece of bone can be removed to shift the relationship between the tendon and the bone. This is called an osteotomy. The results are not always an improvement.
For severe pathology, a patellofemoral arthroplasty (PFA) can be done. This replaces the kneecap and applies a metal cap over the end of the femur where the patella glides up and down. This implant may not be the best answer if there are issues with alignment.
The surgeon may try to rebalance the soft tissues around the knee for more symmetrical tracking. If left uncorrected, the implant may not be able to function properly. For patients with excessive Q-angles, geometry of the implant (size, shape, and function) is important.
The implant must be able to allow some freedom of tracking. If the trochlear (inner) part of the implant is too narrow, the patella may catch on the edge causing a tracking problem. Newer implant designs have actually reduced the maltracking problems that patients used to have routinely.
The best way to find out what can be done about your situation is to seek the opinion of an experienced orthopedic surgeon. A physical exam, patient history, and some simple tests may be all that are needed to answer your questions more specifically.