Methodology for restoring functional leg length in revision total hip arthroplasty.

Functional leg length was measured in 30 patients before and after revision total hip arthroplasty. The authors emphasize the importance of preoperative planning, and determination of adjustment of the leg length should be aimed at a balanced attitude of the entire pelvis and lower back. In order to correct the length inequality, the leg was lengthened in the revision in 25 cases, left unchanged in 2 cases, and shortened in 3 cases. The mean functional leg-length inequality was 13 mm before operation and 4 mm after operation. The mean radiographic inequality between the upper surfaces of the iliac crest was 13 mm before operation and 9 mm after operation. The side operated was more often functionally shorter than the other side before operation, and longer than the other side after operation. The authors emphasize the importance of functional leg length in revision hip arthroplasty. The functional length discrepancy can be corrected in revision, but there appears to be a risk of overlengthening.