Long-term survivorship of hip shelf arthroplasty and Chiari osteotomy in adults.

The current authors retrospectively assessed 56 hip shelf arthroplasties (48 patients) with a mean followup of 17 years (range, 15-30 years) and 89 Chiari osteotomies (82 patients) with a mean followup of 13 years (range, 6-25 years) done in adults with painful hip dysplasia. Preoperative joint space narrowing was observed in 32 of 56 shelf arthroplasties and in 67 of 89 Chiari osteotomies. Survival rates, using hip replacement as the end point, were 37% (20% to 54%) at 20 years for shelf arthroplasty and 68% (54% to 81%) at 18 years for Chiari osteotomy. The severity of preoperative arthrosis was the main factor that impaired the survivorship of shelf arthroplasty and Chiari osteotomy. With arthritic changes without joint space narrowing, the 18-year survival rates were 83% (69% to 97%) for shelf arthroplasty and 94% (89% to 99%) for Chiari osteotomy. Shelf arthroplasty is best indicated for moderate dysplasia (center edge angle >0 degrees) without severe arthrosis. Chiari osteotomy is best suited for severe dysplasia (center edge angle <0 degrees) especially without or with slight arthrosis. Chiari osteotomy also can be a salvage procedure when marked joint space narrowing is present but only if it is related to severe dysplasia (center edge angle <0 degrees).