Objective: we present the long-term behavior of polyethylene’s insert in acetabular implants ARC2F.

Materials and Methods: from 1989 to 1995, 668 THA’s were implanted. Mean patients age was 54 years (28–75). The preoperative diagnosis included: primary OA 501 cases, post-traumatic arthritis 24, hip dysplasia 112, AVN 31. In all cases Omnifit femoral stem with proximal HA coating and ARC2F acetabular component were used. 165 patients (182 arthroplasties) were lost to follow-up. The average time of observation was 15 years (13–18.5).

Results: all THA’s performed well without signs of wear at 10 years. No implant was revised during the first decade because of mechanical loosening. Since then, during the 13th – 14th year, a significant number of patients appeared with symptoms of polyethylene’s massive destruction and significant osteolysis at the femoral and acetabular side of the arthroplasty. We recalled all patients that could be found. Totally, 178 from 486 THA’s had similar radiographic signs of wear. Only 33 of all these had initial wrong orientation of the cup.

Conclusion: despite the excellent early and middle-term results, ARC2F shows rapid and massive wear of the insert after 12 years, probably because of degeneration and loss of polyethylene’s structural integrity due to the method of sterilization. We suggest to recall and inspect all the patients which have this kind of implant more than 12 years.

Objective: The presentation of mid-term results of porous tantalum TMT cup in congenital high hip dislocation.

Materials and Methods: Between November 1997 and December 2000, we performed 27 total hip replacements in 22 women patiens suffering from high congenital hip dislocation according Xartofilakidis classification. The acetabular component was implanted at the true acetabular bed with restoration of the centre of hip rotation. Clinical and radiological observation took place in regular intervals for an average time of 10.2 years (8.5–12 years).

Results: The average Harris Hip Score improved from 48.3 preoperatively (range 15–65) to 89.5 at the latest follow-up (56–100). Oxford hip score declined from 49.5 preoperatively to 21.2 at the first year and to 15.2 at five years examination. The absolute acetabular component’s migration was evaluated by EBRA method in the first 2 years and was at average 0.85 mm at the first year and 1.05 mm at the second year. An incident of gross initial migration was observed. No acetabular revision was performed and there was no case of mechanical loosening.

Conclusion: The acetabular TMT component is highly adhesive and porous with a modulus of elasticity close to subchondral bone. It promotes initial stability, induces bone penetration and integration and offers a more “physiologig” load transfer. It also offers adequate polyethylene thickness, even in the smallest sizes, due to its manufacturing. The recent results from its use in high hip dislocation are excellent and justify the further study of longevity and probably the superiority of this material.