Result of Multiple Frilling for the Early Stage Nontraumatic Osetonecrosis of the Femoral Head

Kim, Young Min; Lee, Duk Yong; Chung, Moon Sang; Kang, Seung Baik; Kim, Byung Sung; Kim, Hee Joong

Abstract

Sixty-six cases of nontraumatic osteonecrosis of the femoral head were treated with multiple drilling using 9/64 inch Steinmann pin from May, 1992 to March, 1996. In this study, the results of the cases that were followed more than 2 years were analyzed. Thirty-three hips of 32 patients were included in this study. One case was lost to follow after the last follow-up at postop 19 months. Diagnosis was made by simple x-ray and MRI in all cases. The stage was classified according to the modified Fic.t classification. The extent of lesion was evaluated on coronal and sagittal images of MRI. Multiple drilling was performed with the patients on fracture table under C-arm control using 9/64 Steinmann pin held on a low speed power drill. Depending on the size of lesions, 4 to 13 holes were drilled into head from the lateral cortex of proximal femur. The average duration of follow-up was 30 months (range, 8-48 months). When a head collapsed or was converted to THRA for any reason, the case was determined to be a failure. There were 14 Ficat stage I, 16 stage IIA, I stage IIB and 2 stage III hips. The extent of lesion was ranging from 10 to 88% with an average of 49%. There were 7 cases of failure (overall success rate, 78%). In 4 cases, collapse of head was detected at postop 12, 14, 14 and 19 months and 3 of them were converted to THRA. Three cases were converted to THRA at postop 8, 21 and 41 months because of recurred pain without collapse on x-ray. Ectopic ossification around drill entry site was the only complication and was detected in 9 cases. Even though the follow-up period is short, multiple drilling of small diameter is very simple procedure and the short-term results were encouraging in early stage osteonectosis.