ADVANTAGES OF THE BI-MODULAR NECK FOR THE THR:RESULTS OF THE FIRST 100 HELIANTHE® FEMORAL STEMSTO AT LEAST FIVE-YEAR FOLLOW-UP

Abstract

Introduction: Mid-term results with a bi-modular stem (neck and head) are reported: 76 implants were reviewed at a mean follow-up of 6.7 years (ranging from 5 to 11 years).

Materials and Methods: The Hélianthe^® femoral stem is manufactured from titanium alloy. It comes in seven sizes and is available with or without cement (HA-coated). A bimodular neck couples with the stem and the prosthetic head trough Morse cones. This unicentric retrospective study includes one hundred three stems in ninety-five patients. All surgeries were performed between 1991 and 1997 following an osteoarthritis requiring total hip arthroplasty in the majority of cases. Twenty-seven patients could not be reviewed (21 died and 6 were lost to follow-up). Therefore out of a group of 68 patients (mean age 77.4 years) 76 hip operations have been reviewed with a mean follow-up of 6.7 years (5–11). Eight patients have been considered as failures, with the implant being recognized as the cause in only five cases. Therefore, 68 hip operations were reviewed among 60 patients (8 bilateral cases) with a mean follow-up of 7.32 years (5–11); these can be divided into 48 cemented stems and 20 stems HA-coated stems. All patients have been evaluated clinically according to Harris and PMA scores. Radiographic evaluation included assessment of the center of motion of the hip, lateralization, and other aspects relating to implant osteointegration.

Results: Results are overall satisfactory with Harris hip score of 91.3 (50–100) and PMA score of 16.4 (12–18). Radiographic evidence shows restoration of the center of motion in most cases with a satisfactory implant fixation in both cemented and cementless stems. Survival rate at more than eight years for 103 stems is 90%.

Discussion: The characteristics of this implant are in accordance with the most recent studies on biocompatibility and morphology requirements of implants indispensable to improve the life-span of hip prostheses. However, the limited follow-up of this study does not provide completely reliable evidence for the choice of this modular stem. All patients need to be followed up for a longer period to validate the good tendency resulting after height years.