FEMUR NECK ROTATIONAL OSTEOTOMY FOR OSTEONECROSIS OF THE FEMORAL HEAD

Introduction Even in localized collapse due to osteonecrosis of the femoral head, a femoral head can be preserved by rotational osteotomy. In addition to anterior rotation, originally described by Sugioka, much more correction can be obtained by posterior rotation. But, transtrochanteric rotational osteotomy needs rather extensive soft tissue release, such as complete capsulotomy and resection of short external rotators and psoas tendons. Many patients tend to complain about the leg length discrepancy and limp due to varus change. We found soft tissue resection and limb shortening could be minimized by doing the osteotomy at the femur neck rather than the trochanteric area following the technique of surgical dislocation. It needs careful dissection of the posterior retinacular artery to preserve circulation to the femoral head. Methods We have performed 17 cases (14 cases were in men and 3 cases were in women), and average patient age was 45 years old. Osteotomy was applied to cases with collapse or large necrotic region that seemed to be fail by core decompression. All cases showed collapse except one (ARCO 2-B) and 6 cases were ARCO 3-A, 5 cases were ARCO 3-B, 4 cases were ARCO 3-C and one case was ARCO stage 4. Seven cases were rotated anteriorly, and ten cases were rotated posteriorly. Amount of rotation was 63 to 170 degrees in posterior rotation (mean 100.8 degrees) and mean 48 degrees in anterior rotation. The size of the necrotic area was 301 degrees according to the Koo method (combined necrotic angle in mid-coronal and mid-saggital MRI scan). Results Harris hip scores were improved from 62 to 88 points and VAS was from 8.4 to 2.6 in 13 cases. Conversion to THA was done in 4 cases (23.5%) as pain was persisting and there was one more failed case which was lost to follow-up. Another 2 cases showed insufficient circulation in bone SPECT, but no symptoms until recently. Problems with fixatives were in 4 cases and one case had heterotopic ossification without symptom. Conclusion In conclusion, the outcome of the operation could be identified much earlier than other procedures. 12 cases (58.8%) showed satisfactory results and 2 cases were in observation due to insufficient circulation, and 5 cases (29.4%) failed. The operative technique will be revised and we are expecting better results.