The topic of this study was to research the survival rate of ATLAS hip prosthesis (acetabular cup) performed by one operating surgeon only and with a minimum of 10 years follow up.

Material and method: The ATLAS cup was hemispheric, in titanium alloy TA6V4, with a thin layer (2.5mm). It had a large central orifice as well as a radial slot allowing a certain elasticity enabling a pressfit impaction. Between January 1989 and December 1995, 297 ATLAS were implanted in the Clinique Saint André of Reims, 171 ATLAS II non hydroxyapatite coated and 126 ATLAS III hydroxyapatite coated. There were 176 women (59,2%) and 121 men (40,8%). The average age was 66 (20 to 94).

Each patient was contacted by phone to find out if the prosthesis was still in place or whether a new operation had been performed. For the deceased patients, the family or the usual doctor were contacted by phone to answer the question with a maximum of details.

The non-parametric survival rates were performed using the actuarial method according to Kaplan-Meier. The results were given with a reliability rate of 95%. The PRISM program was used.

RESULTS: On the 1st of January 2006, out of the 297 patients present at the start, 38 patients (12,8%) could not be contacted, 70 patients (23,5%) had died, 35 were reviewed and 120 answered the phone inquiry.

32 patients had undergone a revision: 23 due to the cup: there were 15 cases of wear of the polyethylene, 4 osteolysis, 3 cases of recurring dislocation and a secondary tilt of the cup, 5 cases of acetabular and femoral revision for 4 femoral loosening (change of cup by principal) and 4 cases of revision of the femoral components only.

The survival rate of the global series of 297 ATLAS (coated and non coated with hydroxyapatite) taking into consideration only the revisions due to the acetabular cup (wear of polyethylene, wrong position) was evaluated at 90% after 10 years and 85,5% after 15 years.

The results were better for the ATLAS III coated in hydroxyapatite: 92,3% after 10 years and 88,4% after 14 years, which confirms the advantages of this surface treatment. In this series, the revision rate for wear of the polyethylene was less important (3%)

With a maximum of 17 years follow up no mobilisation of the insert in the cup had been observed and no metallosis.

Conclusion: The survival rate of the global series of 297 ATLAS (coated and non coated with hydroxyapatite), taking into consideration only the revisions due to the cup (wear of the polyethylene, wrong position) was of 90% after 10 years and 85,5% after 15 years.

The rate was higher for the ATLAS III coated with hydroxyapatite: 92,3% after 10 years and 88,4 % after 14 years, which confirmed the advantages of this surface treatment.

Purpose: The purpose of this work was to study the radiological outcome more than seven years after implantation of 89 anatomic non-cemented femoral stems with hydroxyapatite coating around the metaphyseal circumference.

Material: These 81 patients underwent primary arthroplasty (89 hips) between 1991 and 1994 for joint degeneration or necrosis: 48 men and 33 women, mean age 59 years (range 41–78). The inclusion criteria for this study were physical examination and complete radiographic work-up in the second half of 2001. Mean follow-up was nine years (range 7–10).

Methods: All x-rays were analysed by four independent surgeons who used the Engh and Massin criteria. The evaluators, who had not participated in patient care, made their assessment on the basis of the last follow-up clinical report and x-rays. They search for radiographic evidence of stem stability and bony integration as well as signs of osteolysis using the Gruen criteria.

Results: At last follow-up only one femoral stem was painful, but stable. This stem was revised at seven years. Six cups had been changed due to polyethylene wear with iliac osteolysis but without femoral participation. There were no other reoperations. Polyethylene wear was observed in about one-half the hips (44 hips) and was considered severe (1–2 mm) in nine cases. There were no lucent lines nor reactive lines in the metaphyseal area (zones 1 and 7) but 16% of the hips presented reactive lines along the lower, smooth, part of the stem. Endosteal ossification was observed in zones 2 and 6 in 72% of the hips, and less often (13%) in zones 9 and 13. Five hips (5.6%) exhibited bony growth at the tip of the stem producing a thickening in zone 5; these were the only cases with cortical thickening excepting the revised stem (thickening in zones 2 and 6). There was no case of cortical narrowing. Calcar atrophy was observed in 42 hips (47%) with five showing a “drop” aspect. Four hips exhibited osteolysis of the proximal femur in zone 1A, but there were no images of distal osteolysis of the femur.

Discussion: This independent analysis of 89 x-ray files demonstrated that endosteal growth is frequent in the isthmic region. The radiological tolerance was good for this stem (no cortical changes) but there were modifications of the calcar which were difficult; it could be speculated that certain of these modifications might correspond to localised osteolysis at the lowest part of the joint, migration point of polyethyene debris. The role of hydroxyapatite in the observed absence of distal osteolysis is noteworthy.

Conclusion: At nine years follow-up, the absence of osteolysis of the distal femur despite usual polyethylene wear allows the conclusion that hydoxyapatite coating of the metaphyseal circumference creates an effective barrier against wear debris.