Bosworth hip shelf arthroplasty in adult dysplastic hips: ten to twenty three year results

Hip shelf arthroplasty is currently considered to be a salvage procedure. The aim of the study is to present outcomes of Bosworth hip shelf arthroplasty in adolescent dysplastic hips with a minimum ten-year follow-up.

The basic group comprised 25 hips in 18 patients with the mean age of 31 years (range, 16–52) at the time of operation. Subgroup A included 20 hips that were evaluated prior to operation as spherical, centric hips without osteoarthritic changes (acetabular dysplasia). The heterogeneous subgroup B comprised five hips. Of these, three hips were evaluated as aspheric, without osteoarthritic changes, and two hips as aspheric, with osteoarthritic changes of grade 2 according to Tönnis. In addition, two hips in subgroup B were evaluated as decentred (subluxated), one hip without and one hip with osteoarthritic changes. The mean follow-up was 15 years (range, ten–23).

In subgroup A, the positive effect of operation had lasted at the time of the final follow-up for ten to 22 years postoperatively (average follow-up 14 years) in 19 hips. Only one female patient, 46 years old at the time of operation, developed hip osteoarthritis within ten years, that was treated by THA. In subgroup B, a lasting positive effect of operation was recorded in two cases at the time of the final follow-up (12 and 15 years). The third female patient with an aspheric and decentred hip developed severe hip osteoarthritis 21 years after shelf procedure that was treated by THA. In two patients who had hip osteoarthritis already before the operation, the positive effect of the shelf procedure survived over 13 and 20 years. Although hip osteoarthritis progressed, THA was performed as late as 15 and 23 years after the shelf procedure. The mean Harris hip score in 21 hips with a still functional hip shelf was 68 (range, 56–82) before and 90 (range, 76–100) after the surgery.

The best outcomes of Bosworth hip shelf arthroplasty may be expected in a dysplastic spherical centred hip without osteoarthritic changes. In the presence of asphericity, decentration and osteoarthritic changes, neither the effect of the surgery nor its survival can be clearly predicted.