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Special Hip Socket Implant Helps Prevent Hip Dislocation

Nobody likes to think a new hip joint replacement can dislocate, but it can. Most of the time, surgery is not needed to fix the problem. The hip can be put back in place, and a brace or cast can hold it there. The patient is advised to avoid certain motions and positions for up to six weeks.

However, surgery is sometimes needed. This is the case when the hip dislocates more than once. Doctors don't like to do another operation. Up to 50 percent of these surgeries fail, and the hip continues to dislocate.

This study looked at the use of one particular replacement part called a constrained acetabulum. This is the lining that goes inside the hip socket. Researchers used five different methods to put the liners in place. They report the results for each method.

The constrained acetabulum holds the ball-shaped top of the thighbone (the femoral head) in the socket. The design of the constrained acetabulum helps to keep the femoral head from dislocating. This implant also improves the results of a second operation in the event of another dislocation.

Certain steps taken during surgery help keep this type of implant from dislocating. Pressurized cement fixes the implant in place. Doctors may add stitches to the back part of the hip joint to block the femoral head from slipping out the back of the joint.

Patients are advised to take precautions in order to prevent another hip dislocation. When the surgery is done from the back of the hip, the hip mustn't be bent past 90 degrees (as when bending forward at the waist). Patients must not turn or roll the hip inward, and they must avoid crossing the legs, even at the ankle.

References: Gary S. Shapiro, MD, et al. The Use of a Constrained Acetabular Component for Recurrent Dislocation. In The Journal of Arthroplasty. April 2003. Vol. 18. No. 3. Pp. 250-258.

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