Femoral revision surgery using a fully hydroxyapatite-coated stem: a cohort study of twenty two to twenty seven years.

PURPOSE: Femoral component revision with either cemented or proximally coated stems has been disappointing, but revision with extensively coated stems has been promising. Our purpose was to evaluate the long-term outcome using an extensively hydroxyapatite (HA)-coated stem in femoral revisions surgery.

METHODS: During 1988-1993 we performed 66 femoral revisions in 65 patients (49 women), mean age 58 (range, 28-86) years. We used a grit-blasted straight stem made of TiAl6 V4 designed for press-fit insertion (Landos Corail; Landanger, Chaumont, France). In 48 hips we used primary stems of size 10 in two cases, size 11 in two, size 12 in seven, size 13 in four, size 14 in 12, size 15 in eight, size 16 in 12 and size 18 in one. In 18 cases, we used revision stems of size 12 in four cases, size 14 in seven, size 16 in five and size 18 in two.

RESULTS: During follow-up, 21 patients have died. One patient had a traumatic fracture around the stem after six years, and another patient with osteoporosis developed fatigue fracture of the femoral bone after 22 years. In one patient the cup loosened after 23 years. The cup was revised, but deep infection occurred, and the patient underwent a two-stage revision of both components. Then, 12 of the revised stems were followed for more than ten years and 24 for more than 20 years. During this time only one stem was revised due to mechanical failure. This patient had a femoral defect classified to Type IV, and a proximal fracture occurred when the prosthesis was inserted. The fracture was stabilised by wires, but primary stability of the stem could not be obtained. At control examinations no patients suffered from significant thigh pain, and we noticed a low degree of proximal bone loss and a low incidence of distal bone hypertrophy.

CONCLUSIONS: Our study suggests that a fully HA-coated stem in femoral revision surgery can provide reliable results for up to 27 years. The bone changes confirmed a well-fixed femoral component with a rather physiological transfer of stress from proximal to distal regions with no significant thigh pain.