[Cement-free ACA hip total endoprosthesis--5 years results]

Since 1994 the cementlesss AlloClasssicAdditional (ACA) total hip replacement system is used in the 1st Orthopedic Department of the Hesssing-Stiftung, Augsburg/Germany. Oblique steps on the medial and lateral side of the stem turn negative retrotorsional forces into axial forces and increase rotational stability. The new shape of the self-cutting metric thread of the dual-radius designed acetabular component provides excellent primary fixation without secondary takeover of the force transmission. We checked the medium-term results.

The titanium prosthesis (distributed by Sulzer Orthopedics/Switzerland) was used for primary total hip replacement as a complete system in 1320 cases, as a hybrid system in 96 patients. In revision arthroplasty 156 components have been implanted up to now. All patients are included in a prospective study with radiological and clinical examinations. 176 of 242 primary implanted total hip systems with a minimum follow-up of 5 years had been reviewed.

For the minimum 5 years implanted complete systems, the Harris Hip Score rose from 42 to 91 points. 94% of the patients were mostly or completely satisfied. Thigh pain was reported in 4%. Two aseptic loosenings of the acetabular component and one aseptic loosening of the stem occurred.

A high degree of osseo-integration and complications below 2% proves encouraging outcomes but final acceptance must await long-term follow-up.