Aims: Prospective multi-center study to evaluate the mid-term results of 280 uncemented femoral stem revisions using the modular MRP-Titan system. Methods: 273 patients with 280 MRP-Titan systems, follow-up for a mean time of 3 years (1 to 8 years). Harris hip score for clinical evaluation, bony defect classification according to Paprosky [163 cases (58%) with type 2B, 2C and 3]. Results: Three aseptic loosenings (1%), three septic loosenings (1%), one additional re-revision because of periprosthetic fracture. Postoperative dislocations occurred in 23 cases (8%), 17 of these (6%) were managed by closed or open reposition without changing the implant. In 6 cases (2%) the antetorsion angle of the modular prosthesis neck was altered. Harris hip score: 38 points preoperatively, 85 points at the last follow-up postoperatively. In 18 cases (6.4%) radiolucient lines were seen, but with no progression and no migration of the stems. The overall survival-rate after 8 years of follow-up was 92%. Conclusions: The modular MRP-Titan system has proven to be valuable in quite problematic cases of hip revision arthroplasty with extensive femoral defects. The system allows intraoperative adaptation of implant length and antetorsion angle to the actual situation, a feature not provided by non-modular femoral revision implants.

Aims: The purpose of the study was to obtain long-term results after total hip arthroplasty (THA) with cemented titanium stems typ Mueller-Geradschaft. Methods: 91 patients with a total of 110 THA were clinically and radiologically examined after an average follow-up of 9,5 years (9 to 11). The recruitment was 84%. The Harris score was determined clinically. Radiologically the directly postoperative radiographs were compared to the control radiographs according to the recommendations of Gruen et al. and Johnston et al. Results: In 1 cases (1%) a septical complication appeared after two years which was treated in two-stage surgery. Revisions after aseptic loosening have been carried out in 4 cases (4%). No other cases showed evident signs of loosening and applied revision surgery. Clinically, in all of those 4 cases of aseptic loosening the Harris score remained above 75 points. Altogether in 36 cases more than one RLL was ascertained which were only be observed in zones 1, 7, 8, 14. The body weight was significantly higher (82 kg; d=2.4) in the 4 revisions than in cases without RLL, especially the ratio body weight to surface of the stem was clearly different (1.5 kg/cm2 versus 1 kg/cm2; p< 0.005) in the two patients groups. This did not apply to sex, activity, size or kind of stem, Harris-score, ectopic ossification or body-weight index. Conclusions: Cemented titanium stem protheses showed good long-term results. The biggest possible stem should be implanted. Periodically, radiological controls of THA are necessary because the subjective findings of patients does not correlate to the state of prosthesis loosening