Radiological and Survival Comparison of Four Methods of Fixation of a Proximal Femoral Stem

Abstract

We compared the radiological appearances and survival of four methods of fixation of a femoral stem in 538 hips after follow-up for five or ten years. The fixation groups were: 1) press-fit shot-blasted smooth Ti-A1-V stem; 2) press-fit shot-blasted proximally ridged stem; 3) proximal hydroxyapatite (HA) coating; and 4) cementing. Survival analysis at five to ten years showed better results in the HA-coated (100% at five to six years) and cemented stems (100% at 5 to 6 years) than in the two press-fit groups. There was a higher mean rate of migration in the smooth and ridged Ti-A1-V shot-blasted press-fit groups (0.8 mm/year and 0.6 mm/year, respectively) when compared with the HA-coated and cemented prostheses (both 0.3 mm/year). More radiolucent lines and osteolytic lesions were seen in the press-fit groups than in either the HA-coated or cemented implants, with a trend for a lower incidence of both in the HA compared with the cemented group. Proximal osteopenia increased in the press-fit and cemented prostheses with time, but did not do so in the HA group. There was a higher incidence of resorption of the femoral neck with time in the cemented group than in the other three. We conclude that the HA and the cemented interfaces both provide secure fixation with a trend in favour of HA. The cemented prosthesis meets the suggested National Institutes of Health definition of 'efficacious' at ten years.

High Incidence of Migration with Poor Initial Fixation of the Accolade® Stem

“…Other groups have used EBRA-FCA to study femoral component migration (Table 5), with our overall rate of migration observed with the Accolade 1 stem higher than other stem designs [6,15,29]. In particular, both Radl et al [38] and Kroell et al [29] showed early migration assessed with EBRA-FCA predicted poor long-term clinical performance when greater than 1.5 mm, mirroring the earlier work of Kobayashi et al [26] and Donnelly et al [10]. However, we must be careful in the interpretation of any migration study in regard to what represents the true threshold of migration leading to revision.…”

“…Initial implant fixation is one of the key elements for a successful THA [21,35]. Consequently, migration analysis presents an early objective assessment of the predicted medium-to long-term performance and minimizes the risk of unexpectedly higher rates of later failure with early identification of at-risk components [10,13,25,28,29]. Having observed some early revisions for aseptic loosening of the Accolade 1 stem at our center, we set out to investigate the potential causes by evaluating initial implant stability using migration analysis.…”

Proximal cement fixation in total hip arthroplasty—first results with a new stem design

“…In hip arthroplasty, the transmission of forces acting on the femoral head to the shaft take place through the trabecular system of the proximal femur [4,9,11]. After stem implantation, there is a redistribution of forces, with relief of the bone in the region of the stem.…”

“…After stem implantation, there is a redistribution of forces, with relief of the bone in the region of the stem. This relief leads to bone remodelling or bone loss [9,15,16,17,21]. Atrophy, which often takes place in the proximal part of the femur when prosthetic stems are anchored distally, is an expression of this unphysiological transmission of forces and bone adaptation.…”

“…With cemented stems, the load is transmitted over the entire length of the stem. With a new developed partially cemented prosthetic stem (Option 3000, Mathys Orthopaedics, Bettlach, Switzerland), it has been possible, for the first time, to combine the proximal transmission of force with cement fixation [9]. The stem, which can be anchored in the proximal femur using the press-fit technique, is partially cemented in this region only after the definitive implantation of the stem, and the uncemented polished distal end of the stem is very slender.…”