[Radiologic changes following cement-free implantation of hip prostheses. 5-year follow-up and clinical experience with the cement-free hip prosthesis Autophor-900-S].

Purpose: To evaluate early reliable radiographic signs of loosening in cementless total hip arthroplasty compared to clinical follow-up.

Methods: Within a time interval of 5 years 89 patients with 101 hips underwent total hip arthroplasty using the Autophor 900 S-prosthesis. Clinical and radiographic follow-up were first performed retrospectively followed by a prospective investigation.

Results: Radiographic evaluation showed prosthesis fixation in 93%. Loosening of the prosthesis was identified in 4 cases of the acetabular component and in 4 cases of the femoral stem. Pain was associated with radiographically detectable loosening of the cementless arthroplastic components in only two cases.

Conclusion: Within a follow-up period of up to five years, loosening of cementless total hip arthroplasty occurs in about 7%. The most reliable radiographic signs of loosening are complete radiolucent zones wider than 2 mm at the bone-component interface, progressive subsidence, migration, or tilt of the component. Pain and movement disorders are not specific symptoms and do not necessarily indicate a loosening of the prosthesis.