10 YEARS RESULTS AFTER IMPLANTATION OF THE CEMENTLESS PRESSFIT CUP “ALLOFIT”

Abstract

Introduction: The Allofit cup is a hemispherical pressfit cup with a flattened pole for cementless implantation. Clinical use started in 1993 and we report our clinical and radiographic results of the first 100 cases. 75 hips of this group have been followed during the first 3 to 4 years using EBRA for migration analysis. These results also are presented.

Material: Out of 100 hips 81 have been followed mith a mean of 10,1 years (9,8–11). 6 patients died, 11 did not show for follow up an 1 patient had a revision for deep infection with two-stage exchange meanwhile.

The initial diagnosis was primary coxarthrosis in 63, rheumatoid arthritis in 10, congenital dislocation of the hip in 5 and necrosis of the femoral hed in 3.

In all cases the cementless Alloclassic stem was used, as bearing material metasul was implanted in 73 and ceramic-polyethylene in 8 cases.

Complications: For prolonged exsudation from the wound one soft tissue revision was necessary. 2 luxations were treated conservative. One early deep infection healed after synovectomy and irrigation, one late deep infection was cured by a two stage reimplantation.

Results: The EBRA migration analysis after 3,6 years (2,3–4,2) showed cranial migration of 0,35 mm (0,2–0,6 mm), medial migration of 0,25 mm (0,10–0,40 mm) and a calculated total migration as a combination of both of 0,45 mm (0,22–0,72). Therefore at this time there was no evidence of early loosening or migration indicating later loosening.

The preoperative Harris hip score was 53,13 pts (23–73), the postoperative score after 10 years 96,5 (78–100).

Radiographic evaluation after 10 years showed no lucencies in 78 of 81 jpints. 3 hips had a lucent line of 1mm in zone III. We detected no signs of osteolysis, loosening or migration.

No reoperations for any reason exept 2 septic cases have been performed yet.

Summary: After 10 years the clinical and radiological results of this implant are very satisfying. These results confirm the early observations of a migration analysis performed 6 to 8 years before.