[Chiari's osteotomy. Principles, results and indications. Apropos of 31 cases].

The authors present their experience of 31 cases of Chiari's pelvic osteotomy. The authors recall the principles and the biomechanical objectives of this operation and then they describe the operative technique, which is difficult to master. This osteotomy was performed in patients aged between 15 and 57, gave very good results in 13 cases, good results in 8 cases and mediocre results in 7 cases, of the 28 cases which have been followed up for more then a year. This procedure seems to have a very effective analgesic action, without a marked loss of joint amplitude, but sometimes at the price of a residual limp. This type of osteotomy finds its best indications in arthroses of the hip secondary to marked exposure of the femoral head.