Purpose of the study: Progressive excentration of the femoral head is fequent in the paralytic hip. The result can be dislocation with considerable functional impact even if the subject cannot walk. Once the dislocation becomes permanent,, treatment is difficult. Soft tissue surgery is insufficient. We present our experience with Chiari osteotomy in a series of 28 paralytic hips.

Material and methods: This retrospective analysis included 28 paralytic hips which were operated on from 1974 to 2003. Fourteen patients had cerebral palsy and 14 a cord lesion. Mean age was 18.5 years (range 9–48) at the time of hip surgery. Mean postoperative follow-up was ten years. Prior hip surgery was noted in eleven cases and association with other bone and joint deformities was frequent: scoliosis, oblique pelvis. The Buly classification was noted for patient independence and was ≤ 2 preoperatively for seven patients. Flexion was greater than 80°. Preopeartive excentration was scored according to Reimers: luxation for ten hips and subluxation for 18. Acetabular dysplasia was present in all patients and 19 presented coxa valga. The femoral head was deformed in 14. The objective of the operation was to relieve hip pain and improve hip motion with a good acetabular cover. A chisel was used in all cases for the osteotomy: average 12° ascending cut medially. Associated procedures were: release (n=7), posterior block (n=2), femoral varus osteotomy (n=6), derotation osteotomy (n=6).

Results and discussion: The effect was clearly beneficial in terms of pain relief. There were no stiff hips. No functional degradation was noted and there were no major complications. The Median Reimers index improved from 66% to 19%. Centering was perfect for nine patients and presented residual excentration > 30% for six. There were two cases of femoral head necrosis (on dislocated hips). Seven hips progressed to osteoarthritic degradation and one patient underwent a revision procedure at 14 years for a total hip arthroplasty.

Conclusion: Chiari osteotomy enabled pain relief and improved function in most patients. It stabilized the hip even after dislocation if appropriate procedures are associated. At present however, for dislocated hips, total hip arthroplasty is often proposed. An associated oblique pelvis and scoliosis should be corrected for before surgical treatment of the hip.