Joint resurfacing procedures are typically done in the hip for early stage osteonecrosis. In this procedure, the surgeon removes a small amount of bone from the femoral head (ball) and acetabulum (socket). The surgeon will then place a new surface "cap" on the remaining femoral head and acetabulum. The Birmingham Hip^TM (Smith and Nephew, Inc., Memphis, TN) is the recognized implant approved by the FDA for use in this surgery. It is different from a Total Hip Replacement because it allows for most of the femoral head and all of the femoral neck to be preserved, making this a "bone sparing" surgical technique.

Birmingham femoral resurfacing implant.	Illustration of bone cuts for preparation of femoral resurfacing.
Illustration of implant in place.	Postoperative xray of Birmingham hip replacement.