Introduction

The purpose of this prospective randomized study was to compare the 2-year follow-up penetration of Oxinium versus Metal on polyethylene in a consecutive series of low friction total hip arthroplasty.

Purpose of the study: The purpose of this prospective study was to evaluated the risk of fracture of 22.2 mm Delta ceramic heads.

Material and methods: A preclinical study was performed on twenty 22.2 mm Delta ceramic femoral heads with a medium neck with 20 22.2 mm Delta ceramic femoral heads with a short neck. A V40TM cone was used in all cases with a 5 40 angle. In vitro tests consisted in the assessment of the fracture force under static pressure before and after stress tests, and with a static force shock test (Charpy model) simulating a microseparation during subluxation phenomena. Between April 2007 and April 200, a consecutive series of 55 composite Delta heads were used in 55 patients undergoing cemented total hip arthroplasty (THA). A polyethylene cup was sterilised under vacuum at 3 Mrads with a post-radiation temper (Duration^®), and a stainless steel femoral piece with a highly polished surface and a V40TM Morse cone (Legend^®). This series issued from a randomised prospective study designed to compare wear with 22.2mm Delta ceramic heads with stainless steel heads with the same diameter. Inclusion criteria were age < 75 years, degenerative disease on naive hip and patient residing in France. Mean patient age was 59.2±6.9 years (range 44–70).

Results: The resistance of the 22.2 mm heads was significantly less during the static tests before and after the stress tests. Nevertheless, the mean resistance was higher than the FDA recommendations of 46K. The tests simulating a microseparation showed a significantly superior resistance for the 22.2 mm heads. All patients had from 1 to 2 years follow-up (usual delay for 80% of in vivo ceramic fractures). There were no cases of femoral head fracture in this series. There were no cases of early wear at this same follow-up and no case of femoral or acetabular osteolysis.

Discussion and Conclusion: The results of this study indicate that the resistance of the 22.2mm ceramic Delta heads is very much superior to the recommendations for in vitro tests. In this series, the risk of fracture in vivo remained nil to two years follow-up. The pertinence of this ceramic implant for decreasing polyethylene wear in vivo is under evaluation.

Purpose of the study: The purpose of this prospective randomised study was to evaluate the wear of cemented polyethylene cups as a function of the material of the femoral head: oxinium versus metal.

Material and methods: This series included 50 primary arthroplasties implanted from January 2006 to May 2006 in 50 patients (27 women and 23 men), mean age 60.6±11.4 years (21–75). The same femoral piece made of highly polished M30NW stainless steel with a quadrangular section was used for all implants. Similarly, all patients had a polyethylene cup sterilised with ethylene oxide (CMK21, Smith and Nephew). The femoral head was made of stainless steel for 25 hips and oxinium for 25 hips. The major outcome was penetration of femoral head into the cup (associated with true wear and creep) measured at minimum two years follow-up using the Martell method modified according to the recommendations of the author for an all-polyethylene cup. Patient-related and technique-related factors were studied. Non-parametric tests were used for the statistical analysis.

Results: There was no significant difference between the two groups regarding preoperative data. Two patients died, one was lost to follow-up; for three patients, the radiographs were excluded by the software. The analysis thus included 44 hips with a median follow-up of 2.01 years (1.9–2.3), 22 in the Oxinium™ group and 22 in the metal group. The median penetration rate was 0.16 mm/year in the Oxinium^® group versus 0.19 mm/year in the metal group (Mann-Whitney, p=0.46). Annual volumetric penetration in the Oxinium™ group was comparable with that of the metal group (Mann-Whitney, p=0.76). conversely, using the radiograph taken at one year as the reference value (true wear), wear was 0.066 mm/y in the Oxinium™ group versus 0.19mm/y in the metal group (Mann-Whitney, p=0.38).

Discussion and Conclusion: The results of this series indicate that using an oxinium femoral head reduces polyethylene wear. Mid-term results appear to be necessary to confirm these findings.

Purpose: The cause of Paget’s disease, osteitis deformans, defined by increased bone resorption followed by excessive attempts at repair, remains unclear. The current hypothesis is that bone is slowly infected by paramyxovirus in genetically predisposed patients. We report the case of a patient with monostotic Paget’s disease of the pelvis which was transferred to the homolateral distal femur after total hip arthroplasty.

Case report: A 66-year-old man with Paget’s disease of the hemi-pelvis developed pagetic hip deformation requiring a total hip arthroplasty performed in 1993. A Charnley-Kerboull cemented prosthesis was implanted. The medullary canal was plugged with fragments of cancellous bone harvested from the acetabulum (drill holes required to achieve rotatory stability of the acetabulum). One year later, an asymptomatic osteolytic lesion of the distal femur was identified at the level of the medullary plug. Hip function remained excellent despite extension to the distal and proximal femur. All inflammatory parameters were normal and the femoral component was not loosened. 99m-technetium scintigraphy revealed strong uptake in the pelvis but also in the distal femur under the femoral stem. Isolated femoral stem revision was performed in 1996 as a preventive measure against stress fracture. Pathology analysis of surgical specimens identified Paget’s disease (osteoclast hyperactivity, mosaic aspect of the osteoblasts. After femoral revision with a long stem and medical treatment with biphosphonates, the osteolytic lesion disappeared progressively, taking on the classical sclerous sequelar aspect of osteitis deformans. The disease remained quiescent six years after revision. Hip function remained excellent at last follow-up.

Discussion and conclusion: This is the first report of this type of complication after total hip arthroplasty. This observation that Paget’s disease can be transferred via a autologous cancellous bone graft is in favour of the viral hypothesis, suggesting osteoclastic infection by contiguity. This complication has never been observed with frozen or radiated allograft material although such material may have been harvested from pathological bone, notably with Paget’s disease

Purpose: Revision total knee arthroplasty (RTKA) is particularly difficult and results more variable than primary total knee arthroplasty due to the added problem of bone loss. Massive bone allografts have been proposed to restore bone stock and mechanical conditions as close to the physiological situation as possible. The purpose of this retrospective analysis was to assess clinical and radiological results after knee reconstruction with massive allografts in patients undergoing revision total knee arthroplasty.

Materials and method: This series included 14 patients who underwent a revision procedure between February 1990 and August 1998 for RTKA with segmentary bone loss and bone defects. This group included seven patients with mechanical failure and seven others with septic loosening. Reconstruction was achieved with a massive allograft sealed around a long stem cemented implant. The composite assembly was impacted into the patient’s bony segment. The allografts were used to reconstruct the distal femur in nine cases, the proximal tibia in one, and both in the others. The IKS score and radiographic homogenisation of the host-graft junction were assessment criteria.

Results: Mean follow-up was 50 months (24–110). Mean IKS score was significantly improved from 43 (11–70) pre-operatively to 75 (40–100) at last follow-up (Wilcoxon test, p = 0.002). At last follow-up, the flexion-extension amplitude was 91±10°. Radiographic integration of the allografts was achieved in 14 out of 18 grafts. Three allografts were resorbed leading to fracture with subsequent implant failure and a new revision in two. There were no infections.

Discussion and conclusion: Bone grafts may be a solution to the difficult problem of bone loss during RTKA. Massive grafts combined with long stem implants have given encouraging early and mid-term results. The duration of these results is under evaluation.