Isokinetic Force-Velocity Curves in Patients Following Implantation of an Individual Total Hip Prosthesis

Abstract

There are only a few studies which could support conclusions concerning the strength of the muscles surrounding the hip Joint and especially concerning the strength relationships following implantation of endo-prostheses. The aim of this study was to examine the postoperative course of strength deficits in this musculature compared to clinical parameters.

Fifty-eight patients between 30 and 67 years of age, in whom individual total hip prostheses were implanted, were clinically examined prior, 9 weeks and 6 months after surgery. Moreover, the maximum isometric strengths of abductors, flexors, and rotator muscles as well as maximum isokinetic strengths of the extensors and flexor musculature at 607s and 1207s were measured.

The flexor and extensor musculature already showed a clear increase in maximum strength after 9 weeks and 6 months. By contrast, the isometric strengths of the rotators increased only slightly, the abductor strength decreased after 9 weeks to below the preoperative baseline level and attained this level again only after 6 months. The clinical parameters Trendelenburg sign, limping, and Walking capacity were clearly improved after 6 months, but no correlation to the abductor strength could be demonstrated.

It is concluded that limp-free gait can be attained even without maximum strength increase in the abductors, which are important for fluid gait, at least for short distances. The importance of regular training of the rotator and abductor musculature in coxarthrosis is emphasized to delay limitation of movement and decreased strength in the sense of a capsule pattern.

Key words

Isometric - isokinetic - total hip prostheses - coxarthrosis - strength deficits - walking capacity