Introduction: Metal-on-metal (MOM) hip resurfacing is becoming a more accepted and available option to consider when treating increasingly younger and more active patients. Advantages include preservation of bone stock and a larger femoral head which increases range of motion without risk of dislocation. We report here the effects of gender on revision rates in patients receiving the Cormet 2000 MOM Hip Resurfacing System.

Methods: 1058 hips were implanted in a multicenter, prospective study. All patients received a cementless, press-fit Cobalt Chrome acetabular shell with plasma sprayed titanium and HA coating and cemented Cobalt Chrome femoral head. Patients were evaluated pre-operatively through 2 years using standardized questionnaires, physical examinations, and radiographic evaluations.

Results: There were 754 males (71%) and 304 (29%) females implanted with the device. Thirty-eight (3.6%) revisions were required; 19 females (6.3%) and 19 (2.5%) males. Males had risk factors significant for revision including increased age in 10-year increments and smaller implant size. Trending but not significant (p=0.08) was lower preoperative HHS.

Discussion and Conclusion: There was a difference in revision rates between males and females, likely due to a difference in bone mass and stability. Based on these findings, the optimal patient seemed to be a larger, younger, more active male. This population has previously been identified to be at most risk after THA and utilization of a resurfacing device may be a good alternative. In addition, future studies designed to optimally select females for MOM hip resurfacing may reduce the revision rate in that population.

Introduction: The results of total hip arthroplasty in patients with avascular necrosis of the hip have been variable. This study analyzed the clinical and radiographic outcome of young patients treated with Four different cementless systems, three with alumina-on-alumina bearings in comparison to a control metal-on-poly couple in young patients with avascular necrosis of the femoral head.

Materials and Methods: This was a US IDE multicenter prospective randomized clinical trial begun in 1996 to evaluate safety and effectiveness of alumina-alumina bearings in young patients. Four cementless systems were compared in 95 patients (105 hips), three alumina-on-alumina bearing systems: ABC System I, porous coated cup; ABC System II, hydroxyapatite coated cup; Trident system, hydroxyapatite coated cup with metal sleeve backing on ceramic cup liner. The control group was the ABC System III, porous coated cup with polyethylene and cobalt chromium bearing system. All patients received a cementless Omnifit HA femoral stem. Patients were randomized to receive ABC System I, II, or III. Trident patients (Study arm begun in 1999) were not randomized. Examinations were performed at 7 weeks, 6 months, 1 year, and yearly thereafter including x-rays, clinical exam and modified Harris Hip Scores (HHS).

Results: For the alumina-alumina hips patients had a mean age of 45 years (21–67) with 18 women (23%) and 61 men (77%) at a mean follow up of 4.2 years (range, 2–7). The mean HHS at latest evaluation was 96 points. There were three revisions: one revision of all components for hip pain (sepsis suspected but not confirmed); one stem and head for traumatic postoperative periprosthetic femoral fracture; and one insert and head for subluxation in a patient implanted with the Trident insert and head. For the metal-poly hips, there were similar demographics, follow-up, and clinical scores. There were two revisions; one stem and head for traumatic postoperative periprosthetic femoral fracture, and one insert only 2 days after index surgery for dislocation.

Discussion: Both bearing couples (alumina-alumina and metal-poly) did well in theses cementless hip arthroplasties performed in young patients with avascular necrosis of the femoral head. The low revision rate is encouraging for these previously difficult to treat patients.

Aim: To compare the outcome of open reduction and internal fixation with MUA and k-wire stabilisation of dorsally displaced distal radial fractures

Methods: A review of patients that had ORIF or MUA and k-wire stabilisation for dorsally displaced distal radial fractures was carried out and patients with a follow period of more than 6 months were selected for this study. The patient history and the management of the injury were obtained and the wrist examined. Each patient completed a patient-rated wrist evaluation form and the range of movement and strength of the wrist was determined by the senior occupational therapist. Standard radiographs were obtained and volar tilt, radial inclination and radial length were measured.

Results: This study provides results on 24 patients, which were grouped according to the two different surgical procedures; ORIF and MUA and k-wire stabilisation. The procedure undertaken depended on consultant preferences and in the majority of cases patients were treated with MUA and k-wire stabilisation. Patients of both groups were of similar age and all sustained either a low or medium energy injury. All patients from each group received physiotherapy post operatively.

There was no significant difference between both groups for range of movement and grip strength. There was also no difference between the patient’s perception of pain and function which was assessed using the patient rated wrist evaluation (PRWE). Radiologically, the k-wire stabilisation group averaged better volar tilt compared with the ORIF group. For radial height and inclination the outcome was similar.

Conclusion: MUA and k-wire stabilisation has been the most popular surgical management for unstable dorsally displaced fractures of the distal radius. More recently ORIF with the locking compression plate has been used with good results. This study showed that the outcome of ORIF and MUA and k-wire stabilisation were similar and therefore either surgical management can be used with good results.

Introduction: Wear simulator studies have predicted that highly cross-linked polyethylenes can reduce linear wear by 50–90% when compared to traditional polyethylene (gamma sterilized in air). Clinical experience with a highly cross-linked polyethylene which was irradiated to 10 megarads and cold anneled but not remelted (Crossfire) began in October 1998.

Methods: 72 Crossfire implants (69 patients) were implanted and have a minimum 3 year follow-up (mean 3.85 years). 31 of these implants (29 patients) have a minimum 4 year follow-up (mean 4.64 years). Linear wear utilizing a validated computerized technique was measured and compared to 38 hips (37 patients) implanted with a non-cross-linked polyethylene (gamma irradiated – N2 vac) with a mean follow-up of 4.96 years.

Results: The mean wear in millimeters per year for the highly cross-linked Crossfire polyethylene with minimum 3 year follow-up was 0.054 (sd=0.032). At minimum 4 year follow-up wear was 0.057 mm/yr (sd=0.036). The wear for the N2 vac non-cross-linked polyethylene was 0.138 mm/yr (sd=0.066). Using a standard t-test the difference in wear was highly significant at p=< 0.001.

Discussion & Conclusion: Cross-linking is the only material characteristic shown to improve wear performance of polyethylene. Our clinical experience demonstrates a 50% reduction in wear over N2 vac irradiated polyethylene during the first three years with no significant change out to a mean of 4.64 years. Cross-linked polyethylenes hold great hopes for significant reduction in wear and osteolysis and prolonged life of hip arthroplasty in patients of all ages.