Biological repair of acetabular bone defects after impaction bone grafting (IBG) in total hip arthroplasty could facilitate future re-revisions in case of failure of the reconstruction again using the same technique. Few studies have analysed the outcome of these acetabular re-revisions. We analysed 34 consecutive acetabular re-revisions that repeated IBG and a cemented cup in a cohort of 330 acetabular IBG revisions. Fresh-frozen femoral head allografts were morselized manually. All data were prospectively collected. Kaplan-Meier survivorship analysis was performed. The mean follow-up after re-revision was 7.2 years (2–17). Intraoperative bone defect had lessened after the first failed revision. At the first revision there were 14 hips with Paprosky 3A and 20 with Paprosky type 3B. At the re-revision there were 5 hips with Paproky 2B, 21 with Paprosky type 3A and 8 with type 3B. Lateral mesh was used in 19 hips.Introduction
Patients and Methods
Impaction bone grafting (IBG) is a reliable technique for acetabular revision surgery with large segmental defects. However, bone graft resorption and cup migration are some of the limitations of this tecnique. We assess frequency and outcome of these complications in a large acetabular IBG series. We analysed 330 consecutive hips that received acetabular IBG and a cemented cup in revision surgery with large bone defects (Paprosky types 3A and 3B). Fresh-frozen femoral head allograft was morselized manually. The mean follow-up was 17 years (3–26). All data were prospectively collected. Kaplan-Meier survivorship analysis was performed. Changes in different paremeters regarding cup position were assessed pre- and postoperatively and at the follow- up controls. Only variations greater than 5º and 3 mm were considered.Introduction
Patients and Methods
As there are many reports describing avascular reactions to metal debris (ARMD) after Metal-on-Metal Hip Arthroplasty (MoMHA), the use of MoMHA, especially hip resurfacing, is decreasing worldwide. In cases of ARMD or a rise of metal ion blood levels, revision is commended even in pain free patients with a well integrated implant. The revision of a well integrated implant will cause bone loss. As most of the patients with a hip resurfacing are young and a good bone stock is desirable for further revision surgeries, the purpose of this study was to evaluate the stability of a cemented polyethylene cup in a metal hip resurfacing cup. Two different hip resurfacing systems were investigated in this study (ASR™, DePuy Orthopaedics, Leatherhead, UK; Cormet™, Corin Group, Cirencester, UK). Six different groups were formed according to the treatment and preparation of the cement-cup-interface (table 1). Before instilling cement in groups 1, 3, 5 the surface, which was contaminated with blood, was cleaned just using a gauze bandage. In groups 2, 4, 6 saline, polyhexanid and a gauze were used to clean the surface prior to the cement application. In group one and two the polyethylene cup (PE) was cemented either into Cormet™ or ASR™, just the ASR™ was further investigated in group three to six. A monoaxial load was applied while the cup was fixed with 45 degrees inclination (group 1–4) and 90 degrees inclination (group 5, 6: rotatory stability) and the failure torque was measured. In contrast to group 1 and 2, the cement penetrated the peripheral groove of the ASR™ in groups 3–6. The mean failure torque of five tests for each group was compared between the groups and the implants. The ASR™ showed mean failure torque of 0.1 Nm in group one, of 0.14 Nm in group two, of 56.9 Nm in group three, of 61.5 Nm in group four, of 2.96 Nm in group five and of 3.04 Nm in group six. The mean failure torque of the Cormet™ was 0.14 Nm both in groups one and two (table 2). In groups 1–6 there were no significant differences between the different preparations of the interface. Furthermore, in groups 1 and 2 there were no significant differences between the Cormet™ and the ASR™. The mean failure torque of group 4 was significant increased compared to group 3 (p=0.008). We saw an early failure of the cement fixation due to the smooth surface of the Cormet™ and the ASR™ components in groups 1, 2, 5, 6. In contrast to other hip resurfacing cups the ASR™ has a peripheral groove, which was not cemented except in groups 3 and 4 and therefore the lever-out failure torque was significant increased in these groups. Nevertheless, the groove did not provide stability of the cement-PE compound in case of rotatory movements. In conclusion we do not recommend the use of these methods in clinical routine. The complete removal of hip resurfacing components seems to be the most reasonable procedure.
We have prospectively followed up 191 consecutive primary total hip replacements utilising a collarless polished tapered (CPT) femoral stem, implanted in 175 patients between November 1992 and November 1995. At a mean follow-up of 15.9 years (range 14 – 17.5) 86 patients (95 hips) were still alive (25 men and 61 women) and available for routine follow up. Clinical outcome was determined from a combination of the Harris (HHS) and Oxford (OHS) hip scores. Radiological assessment was with antero-posterior radiographs of both hips and a lateral radiograph of the operated hip. The radiographs were evaluated using well-recognised assessment techniques. There was no loss to follow up, with clinical data available on all 95 hips. Five patients were too frail to undergo radiographic assessment, therefore radiological assessment was performed on 90 hips (95%). At the latest follow-up, the mean HHS was 78 (range 28 – 100) and the mean OHS was 36 (range 15 – 48). Stems subsided within the cement mantle, with a mean total subsidence of 2.1mm (range 0.4 – 24). Higher grades of heterotopic bone formation were significantly associated with males (p<0.001) and hypertrophic osteoarthritis (p<0.001). Acetabular wear was associated with increased weight (p<0.001) and male sex (p=0.005). Amongst the cohort, only 1 stem (1.1%) has been revised due to aseptic loosening. This patient required reaming of their canal prior to implantation, as a result of a previous femoral osteotomy. The rate of stem revision for any cause was 7.4% (7 stems), of which 4.2% (4 stems) resulted from infection following revision of the acetabular component. Twenty patients (21.1%) required some sort of revision procedure; all except 3 of these resulted from failure of the acetabular component.
