I thought I was going to be spared having a total hip replacement by going for joint resurfacing. But I ended up with a hip fracture and a second surgery to replace the hip anyway. No one seems to know what caused the problem. What are some possible reasons for this happening to me?

Hip joint resurfacing instead of a total hip joint replacement is fairly new. Resurfacing replaces the arthritic surface of the joint but removes far less bone than the traditional total hip replacement. It saves bone in the femoral neck but can put strain on the femoral neck leading to fractures.

There are two main groups of risk factors for fracture after joint resurfacing. The first has to do with the patient. Bone quality is important. Decreased bone-mineral density and cystic bone changes can contribute to weakened bone. The bone has a decreased ability to withstand forces leading to fracture.

Any changes in natural alignment of the hip can result in mechanical abnormalities. The most common of these malalignments are coxa varus (angled inward) and coxa breva (short femoral neck).

The second group of risk factors is related to the surgical procedure. Placement of the component is important. If the implant is tilted or angled too far in any direction, loading patterns change. The risk of fracture increases. The surgeon also uses a special technique called notching as part of the procedure. Studies show that notching reduces the bone's resistance to fracture.

Sometimes it isn't clear what went wrong. Efforts are being made to identify patients who are good candidates for joint resurfacing. Bone quality, general health, and past medical history are important features to consider. At the same time, surgeons are looking for ways to improve the implant and surgical techniques used.