How do different designs of femoral stem affect total hip arthroplasty applied to Crowe type III and type IV dysplastic hips

Purpose: A comparison was made of the clinical and radiological results of cylindrical fully porous-coated femoral stems (Group A) and Zweymuller-type femoral stems (Group B) used for the treatment of hip osteoathrosis, secondary to Crowe III and IV dysplasia, with total hip arthroplasty combined with femoral transverse shortening osteotomy. Method: This study is a retrospective evaluation of 86 hips in 50 patients. Group A comprised of 43 hips and Group B comprised of 43 hips. During final follow-up evaluation, patients were clinically assessed with Harris Hip Score (HHS), Merle d'Aubigne-Postel scale (MAP), and SF-36 scale. For radiological examination the Gulman THA score was used. Femoral osteotomy union, osteolysis around the components and component migration were also recorded and evaluated. Results: In Group B, nonunion of the osteotomy site was found in 18.6% and delayed union in 20.9% of the hips. In Group A, delayed union was found in 7% of the hips. Patients' mean daily walking distance was found to be lower in Group A when compared to Group B. When the postoperative clinical HSS, and MAP and the radiological Gulman scores were compared, no statistically significant differences (p = 0.275) were found. Conclusions: Patients with hip osteoarthritis secondary to Crowe III and IV dysplasia, who were treated with THA and transverse osteotomy showed a higher incidence of osteotomy complications when the Zweymuller femoral stem was used. However these complications did not affect clinical outcomes.