We evaluated intermediate-term results of primary cementless Omniflex prostheses.

Forty-nine patients (57 hips) with a mean age of 44 years were observed for an average of 8.6 years.

These results were inferior to those using other recent cementless total hip systems. The increasing prevalence of loosening and osteolysis with time are problems related to this Omniflex femoral component. Although the implant design is unique, the authors no longer use this system.

Introduction: This study evaluated the sphericity of bearing surfaces in total hip arthroplasty.

Methods: All the prosthetic metal femoral heads and the UHMWPE liners evaluated in this study were obtained straight from manufacturers (DePuy Johnson and Johnson, Howmedica Osteonics, Kyocera, Smith and Nephew, Zimmer). Out-of-roundness was assessed as an indicator representing sphericity. A total of 50 femoral heads and 22 UHMWPE liners were evaluated in 1995. Out-of-roundness of ball bearings were measured for the control study. A total of 43 femoral heads and 40 UHMWPE liners were evaluated in 1999 and 2000.

Results: The out-of-roundness of the femoral heads and the UHMWPE liners were significantly inferior to those of ball bearings. The out-of-roundness of the UHMWPE liners was significantly inferior to that of the femoral heads. The out-of-roundness of the femoral head on the sagittal plane was significantly inferior to that on the transverse plane. Several significant differences were found among different manufacturers. Overall, the out-of-roundness of the femoral head on the sagittal plane and UHMWPE liners had improved significantly in 1999/2000 compared to that in 1995.

Discussion: We previously reported that UHMWPE wear in poor out-of-roundness coupling (femoral head: 9.5 μm, socket: 36 μm) was 148% greater compared to those in good out-of-roundness coupling (femoral head: 0.5 μm, socket: 0.6 μm) at 1 million cycle experiments (J Arthroplasty 15:332, 2000). Some prosthetic femoral heads indicated more than 9.5 μm out-of-roundness in the present study, and these femoral heads with poor sphericity might be unfavorable to wear if implanted. We consider that sphericity of UHMWPE liners should be also improved to reduce initial UHMWPE wear. The sphericity of bearing surfaces can be improved by appropriate changes in manufacturing technique. Further improvement is desirable, since this is expected to prolong the functional performance of the prosthesis after total hip arthroplasty.

Total knee arthroplasty (TKA) after proximal tibial valgus osteotomy is thought to be technical demanded and its outcome is not as sufficient as primary TKA. Purpose of this study is to identify particular surgical procedures and outcome of TKA after proximal tibial valgus osteotomy in the different type of osteotomies. Fourteen TKA after proximal tibial valgus osteotomies were underwent for 13 patients with osteoarthritis. Average age at surgery was 72 years old. The mean duration from proximal tibial valgus ostetomy to TKA was 9 years and 10 months and the mean follow up period after TKA was three years and nine months. Four closed wedged osteotomies, five modified Levy’s reversed V shaped osteotomies and five domed osteotomies were underwent before TKA. The V-Y lengthening of quadriceps tendon or osteotomy of the tibial tubercle was necessary for each one knee. Both knee had patella infera due to previous osteotomies of tibial tubercle for patello- femoral osteoarthritis. 11 lateral releases including release of lateral collateral ligament and two lengthening of iliotbial tract were needed to achieve sufficient ligament balance. The stems of tibial components could be placed almost centrally especially in knees, which had reversed V shaped oseteotomies and laterally in knees, which had domed or closed wedged osteotomies. Clinical results evaluated by Japan Orthopedic Association score had improved from 53 points before TKA to 84 points after TKA. This study suggests that 1) approach is difficult in the knee, which had previous osteotomy of tibial tubercle, 2) lateral release including lateral collateral ligament and iliotibial tract is necessary to achieve sufficient ligament balance, 3) the stem of tibial component might be placed laterally in knees, which had previous domed oseteotomy or closed wedged osteotomy, 4) outcome of TKA after proximal valgus osteotomy is as good as primary TKA.

The aim of the study was to compare clinical results after cruciate-retaining total knee arthroplasty (TKA) between the ceramic and the Co-Cr alloy condylar prostheses.

In a prospective semi-randomised study, 218 patients underwent cruciate-retaining TKA with the Co-Cr alloy prosthesis (Kinemax®, Howmedica) or the LFA-I® prosthesis (Kyocera) composed of an alumina ceramic femoral component and a titaniumalloy tibial component with a UHMWPE insert. In each surgery, both components were fixed with PMMA cement. All the patients underwent the same postoperative management. Finally, 110 knees with the ceramic prosthesis and 84 knees with the Co-Cr prosthesis were followed up for 24 to 124 months (the average of 56 months).

Two revisions were performed in each group (tibial tray breakage and infection in the ceramic group, and loosening and infection in the Co-Cr group). In the remaining patients, there were no significant differences in the HSS knee score (85 and 86 points, respectively) and the ROM (112 and 113 degrees) between the two groups. In radiological evaluation, a radiolucent line was more frequently observed with the significance (p< 0.05) in the Co-Cr alloy group (9.5 %) than in the ceramic group (2.7 %).

In the mid-term follow-up evaluations, the clinical results of the ceramic TKA are equivalent to those of the Co-Cr alloy TKA. In addition, the ceramic prosthesis showed some statistical tendency of superiority to the Co-Cr prosthesis concerning the radiolucent line. These results encouraged us to conduct a long-term follow-up study on the ceramic total knee prosthesis.

From 1996, we were added fenestration between coronoid fossa, and olecranon fossa at the time of debridement arthroplasty termed extensive debridement arthroplasty with medial and lateral approach.The purpose of this study is to investigate clinical results of extensive debridement arthroplasty.

17 cases could be followed more than two years. Their averaged age was 57.3 years old. Two elbows had a previous history of debridement arthroplasty. In preoperative averaged flexion angle was 105 and averaged extension was 28C Clinical evaluation was performed with the elbow score of Japanese Orthopedic Association Preoperative averaged JOA score was 54.6 points In ray study we investigated whether the fenestration was open or closed.

In all cases, their symptoms improved D All patients returned to their former occupations satisfied with the clinical results Infection postoperative fracture and ectopic ossification were not observed.The averaged JOA score was 91 points Postoperative averaged flexion was 127 averaged extention was 12_Improvement of extension was 16 and that of flexion was 22 Closure of the fenestration was observed in five elbows Osteophyte formations of the coronoid process and olecranon was seen in 4 elbows

The JOA score of pain and ROM of these results were superior compared with any reports of debridement arthroplasty.The JOA score and results of ROM were superior when the fenestration was open.To maintain the fenestration hole open some modification will be necessary

Short term results of extensive debridement arthroplasty showed satisfactory results in terms of pain relief and Improvement of ROM, especially in extension.