INTRODUCTION: Custom-made prosthesis in primary hip arthroplasty based on the concept of a better press-fitting to reach superior clinical results in comparison to conventional implants. Mid-term results provide a more complete picture with respect to gait and electromyographic analyses. MATERIALS AND METHODS: The custom-made femoral component (Adaptiva) was implanted in 24 hips and compared to 23 hips with a conventional implant (Alloclassic-SL). The mean retrospective follow-up times were 3.9 (3-4.9) years and 4.8 (3.1-5.1) years. Clinically, the Harris Hip Score (HHS) and the SF 36 were recorded. Motion analysis data (body kinematics, kinetics and muscle activities) were recorded with 3D gait analysis. RESULTS: Neither the HHS nor the SF-36 revealed any statistical differences between the two groups (P > 0.05). The radiographic parameters did not show the intended physiologic load transfer. Periprosthetic changes indicated a more distal load transfer of the customized stem. Gait analysis revealed in comparison to the controls (45.03 degrees ), a reduced mean hip range of motion in the sagittal plane by 11.4% (39.9 degrees ) in the customized stem group versus 17.4% (37.2 degrees ) in the conventional stem group. In keeping with the limited range of hip motion kinematic impairments of the ipsilateral knee and ankle joints were detected. The electromyographic amplitudes of the tensor fasciae latae and gluteus medius muscles both for stabilizing the hip joint in the stance phase were significantly higher in both groups. CONCLUSION: Compared to a conventional cementless hip prosthesis the custom-made device did not improve the mid-term clinical and radiographic outcome. Despite the individualized reconstruction of the biomechanical hip geometry objective gait analysis failed to show a benefit.
INTRODUCTION: Custom-made prosthesis in primary hip arthroplasty based on the concept of a better press-fitting to reach superior clinical results in comparison to conventional implants. Mid-term results provide a more complete picture with respect to gait and electromyographic analyses. MATERIALS AND METHODS: The custom-made femoral component (Adaptiva) was implanted in 24 hips and compared to 23 hips with a conventional implant (Alloclassic-SL). The mean retrospective follow-up times were 3.9 (3-4.9) years and 4.8 (3.1-5.1) years. Clinically, the Harris Hip Score (HHS) and the SF 36 were recorded. Motion analysis data (body kinematics, kinetics and muscle activities) were recorded with 3D gait analysis. RESULTS: Neither the HHS nor the SF-36 revealed any statistical differences between the two groups (P > 0.05). The radiographic parameters did not show the intended physiologic load transfer. Periprosthetic changes indicated a more distal load transfer of the customized stem. Gait analysis revealed in comparison to the controls (45.03 degrees ), a reduced mean hip range of motion in the sagittal plane by 11.4% (39.9 degrees ) in the customized stem group versus 17.4% (37.2 degrees ) in the conventional stem group. In keeping with the limited range of hip motion kinematic impairments of the ipsilateral knee and ankle joints were detected. The electromyographic amplitudes of the tensor fasciae latae and gluteus medius muscles both for stabilizing the hip joint in the stance phase were significantly higher in both groups. CONCLUSION: Compared to a conventional cementless hip prosthesis the custom-made device did not improve the mid-term clinical and radiographic outcome. Despite the individualized reconstruction of the biomechanical hip geometry objective gait analysis failed to show a benefit.