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

The human cystein-rich protein 61 (hCYR61) belongs to an emerging family of genes which modulate growth and differentiation. Previously, hCYR61 was identified by us as a fast and transiently 1,25(OH)2-vitamin D3 responsive gene product in human osteoblasts by differential display PCR. Here, we further studied the role of the protein in human osteoblasts.

Using the human hFOB cell line hCYR61 mRNA was analysed by northern hybridisation. Protein levels were detected using western blotting. Intracellular localisation of the hCYR61 protein was determined using the expression as a fusion protein with green fluorescent protein. Immunohistology was performed in hFOB cells as well as primary human osteoblasts and human bone samples.

From northern analyses the hCYR61 mRNA was regulated by 1,25(OH)2-vitamin D3 as well as the growth factors TNFa, EGF, bFGF and IL1b 5-10-fold within 1 hour in the hFOB cell line. Here we show that the same factors markedly upregulated the hCYR61 protein within 24 to 48 hours in hFOB cells as has been analysed by western blotting. From cellular supernatants a highly upregulation of the hCYR61 protein by the growth factors was observed. A full length hCYR61 protein fused to the green fluorescent protein localised to the Golgi-apparatus. From immunohistology proliferating hFOB cells and primary osteoblasts express significant hCYR61 protein, whereas differentiated osteoblasts display a marked downregulation of hCYR61. In human bone high levels of hCYR61 were observed at the human growth plate as well as on surfaces of mineralised structures.

In summary, hCYR61 in human bone represents an immediate early regulated gene. The secreted protein plays a role as an extracellular matrix signaling protein which could play an important role in cell-cell communication within the bone microenvironment. The high expression level and regulation patterns observed in our studies suggest an important role in situations of bone repair and remodeling.

We have carried out a prospective, randomised study of prophylaxis for heterotopic ossification (HO) comparing indomethacin for 7 and 14 days, acetylsalicylic acid, and fractional (4 × 3 Gy) or single exposure of 5 or 7 Gy irradiation after operation.

We initially had 723 patients (733 hip replacements), but after withdrawals there were 685 hips of which 18.4% developed HO; 14% were grade I, 2.9% grade II and 1.5% grade III of the Brooker classification.

We compared the results between these groups with those of a matched control series and found that indomethacin, 2 × 50 mg for 7 and 14 days, and postoperative irradiation of 4 × 3 Gy or 1 × 7 Gy, significantly reduced the development of HO compared with the control group. Patients in the acetylsalicylic acid group and those with a single irradiation of 5 Gy after operation developed significantly more ossification than those in the indomethacin and other irradiation groups.

We suggest the use of 2 × 50 mg of indomethacin with mucoprotection for seven days as prophylaxis against HO after total hip replacement for all patients. A single irradiation of 7 Gy is recommended for patients who have developed HO after previous operations or to whom administration of indomethacin is contraindicated.