Evaluation of the results from proximal fixation of uncemented conical femoral components in Dorr type C femurs

Abstract

ObjectiveTo evaluate the results from proximal fixation of uncemented conical femoral components in patients with a type C proximal femur and compare them with the results obtained from type A and B femurs.MethodsThis was a retrospective study on 87 patients with 90 uncemented total hip arthroplasty procedures. Three patients (three hips) were excluded because their follow-up lasted for less than two years. The follow-up ranged from 2 to 4.3 years and the mean was 2.8 years. The Bicontact femoral implant model was used. The preoperative radiographs were evaluated, the femurs were classified as Dorr types A, B or C and the cortical indices were measured. The patients were evaluated clinically by means of the Harris Hip Score (HHS), before the surgery and at the last follow-up. The sequences of postoperative radiographs were compared regarding stability, complications and any signs of osseointegration of the femoral prosthesis.ResultsAmong the 87 hips with follow-up greater than two years, 32 femurs were type A (37%), 37 type B (42%) and 18 type C (21%). Before the operation, the mean HHS was 39.4 for types A and B and 38.8 for type C. At the last follow-up, the mean HHS was 89.8 for types A and B and 86 for type C. None of the 87 femoral components had been revised by the time of the last follow-up; all of them were considered stable. In 86 cases, the radiographs showed signs of osseointegration.ConclusionThere were no significant differences in the clinical results or in the fixation (and osseointegration) of conical uncemented femoral prostheses with proximal porosity, among femurs with different types of femoral morphology according to the Dorr classification. This conclusion may vary if another implant model were to be used.

Three-Dimensional Analysis of the Contact Pattern between the Cortical Bone and Femoral Prosthesis after Cementless Total Hip Arthroplasty

“…Pellegrini et al [ 14 ] reported that radiolucent lines were seen around 30% of porous-coated stems, most commonly in zones 1, 4, and 7, and that these lines were not progressive. Ahmad Hatem et al [ 15 ] followed up 138 patients using the Taperloc stem for a mean of 10 years and described that reactive lines were seen in the region of the stem in 75 hips (69%), most commonly in zone 4. Oh et al [ 13 ] reported good clinical outcomes for a DCPD-coated stem, with reactive lines around the tip of the stem found in 35% of hips.…”

“…Reactive lines were observed in 57 hips (66%) in the distal part after a mean follow-up of 2.8 years [ 16 ] and in 9 hips (8.7%) after a mean follow-up of 22.8 years [ 17 ]. Reactive lines in noncoated distal stem parts cannot be regarded as a sign of radiological loosening [ 15 – 17 ]. Like the Excia stem, the Bicontact stem has anteroposterior support flanges together with a lateral derotational wing, and the distal tapered part of the stem is smooth and uncoated.…”