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 Zweymüller-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 Zweymüller femoral stem was used. However, these complications did not affect clinical outcomes.