Resurfacing Group Research Articles

Metal-on-Metal Hip Resurfacing Compares Favorably with THA at 2 Years Followup

Metal-on-metal total hip resurfacing is a bone-conserving reconstructive option for patients with advanced articular damage. While intended to address several problems with conventional THA, the safety and efficacy is not well established. We therefore retrospectively compared the outcomes of 52 patients (57 hips) with resurfacing arthroplasty to 84 patients (93 hips) with cementless primary THAs. The patients had a minimum 2-year followup (mean 3 years). The patients with resurfacing arthroplasty had a mean age of 47 years (range, 22-64) while those with cementless primary THA had a mean age of 57 years (range, 17-92). After controlling for age, gender, and preoperative differences, the total Harris Hip Scores (HHS), function scores, and pain scores were similar between the two groups. However, the resurfacing group had higher activity scores (14 versus 13, p < 0.001) and range of motion (ROM) scores (5.0 versus 4.8, p < 0.001). The complication rates (5.3% for resurfacing versus 14.0% for THA) and reoperation rates (3.5% for resurfacing versus 4.3% for THA) were similar. The total hip arthroplasty and metal-on-metal resurfacing groups both showed improvement in HHS, pain, activity, and ROM and had similar early complication and reoperation rates.

Treatment of the young active patient with osteoarthritis of the hip

We compared the five- to seven-year clinical and radiological results of the metal-on-metal Birmingham hip resurfacing with a hybrid total hip arthroplasty in two groups of 54 hips, matched for gender, age, body mass index and activity level. Function was excellent in both groups, as measured by the Oxford hip score, but the Birmingham hip resurfacings had higher University of California at Los Angeles activity scores and better EuroQol quality of life scores. The total hip arthroplasties had a revision or intention-to-revise rate of 8%, and the Birmingham hip resurfacings of 6%. Both groups demonstrated impending failure on surrogate end-points. Of the total hip arthroplasties, 12% had polyethylene wear and osteolysis under observation, and 8% of Birmingham hip resurfacings showed migration of the femoral component. Polyethylene wear was present in 48% of the hybrid hips without osteolysis. Of the femoral components in the Birmingham hip resurfacing group which had not migrated, 66% had radiological changes of unknown significance.

The association between metal ions from hip resurfacing and reduced T-cell counts

We have studied the relationship between metal ion levels and lymphocyte counts in patients with metal-on-metal hip resurfacings. Peripheral blood samples were analysed for lymphocyte subtypes and whole blood cobalt and chromium ion levels in 68 patients (34 with metal-on-metal hip resurfacings and 34 with standard metal-on-polyethylene total hip replacements). All hip components were radiologically well-fixed and the patients were asymptomatic. Cobalt and chromium levels were significantly elevated in the patients with metal-on-metal hip resurfacings, compared with the patients with standard metal-on-polyethylene designs (p < 0.0001). There was a statistically significant decrease in the level of CD8(+) cells (T-cytotoxic/suppressor) (p = 0.005) in the metal-on-metal hip resurfacing group. A threshold level of blood cobalt and chromium ions was associated with reduced CD8(+) T-cell counts. We have no evidence that our patients suffered as a result of this reduced level of CD8(+) T-cells.

Clinical and biomechanical assessment of patella resurfacing in total knee arthroplasty

Currently there is a limited understanding of the factors influencing range of motion by comparing patellar resurfacing vs non-resurfacing in total knee arthroplasty during activities of daily living. A recent meta-analysis of patellar replacement confirms better outcome with patella resurfacing; however, the result can be influenced by many other factors, such as: component design, surgeon experience, and technical aspects of the surgery. This study compares the biomechanics of the knee in patients after total knee arthroplasty with and without patellar resurfacing during stair climbing. Forty-seven patients with total knee arthroplasty were assessed at the mean follow-up of 24 months. In all of them a posterior stabilised fixed bearing prosthesis (Optetrak PS, Exactech) was implanted. Twenty-six patients were treated without patellar resurfacing and 21 with patellar resurfacing. Clinical evaluations were performed using the International Knee Society and the Hospital for Special Surgery scores. Ten patients with patellar resurfacing and 10 patients without patellar resurfacing were also studied with motion analysis during stair climbing; 10 healthy subjects were studied for statistical comparison. Clinical passive knee flexion, International Knee Society Function and Hospital for Special Surgery scores were significantly higher in the patellar resurfacing group. During stair climbing, active knee joint range of motion during the stance phase was greater in patients with patellar resurfacing. The maximum adduction moment was significantly higher in the group without patellar resurfacing. Patients with patellar resurfacing demonstrated better clinical scores, and kinematic and kinetic data while ascending stairs.

Comparative Analysis between Patellar Resurfacing and Retention in Total Knee Arthroplasty: 5-year Follow-up Result

Purpose: To compare the clinical and radiological results between patellar resurfacing, group and patellar retention group in total knee arthroplasty. Materials and Methods: Of the 74 patients who underwent total knee arthroplasty on due to knee osteoarthritis since March 1996, and followed-up for at least for 5 years, there were 42 and 32 cases in the patellar retention and patellar resurfacing groups respectively. These subjects were evaluated preoperatively and at 1 and 5 years postoperatively using the pain score, Hospital for Special Surgery (HSS) knee score, walking and stair-climbing in knee function score and radiological analysis. The radiological evaluation was achieved by measuring the patellar tilt angle and displacement with a merchant view. The results were analyzed using the student,s t-test. Results: There were no significantly differences between the patellar resurfacing and patellar retention groups in the pain score, HSS knee score, walking in knee function score and radiological analysis (p>0.05), but the patellar retention group achieved superior results in stair-climbing (p

Patellar Resurfacing in Total Knee Arthroplasty

Background: Anterior knee pain following total knee arthroplasty is a common complaint and typically is attributed to the patellofemoral joint. The purpose of the present study was to compare the outcome of resurfacing and nonresurfacing of the patella, particularly with regard to anterior knee pain, and to clarify the indications for patellar resurfacing at the time of total knee arthroplasty. Methods: We performed a prospective, randomized study of 514 consecutive primary press-fit condylar total knee replacements. The patients were randomized to either resurfacing or retention of the patella. They were also randomized to either a cruciate-substituting or a cruciate-retaining prosthesis as part of a separate trial. The mean duration of follow-up was 5.3 years (range, two to 8.5 years), and the patients were assessed with use of the Knee Society rating, a clinical anterior knee pain score, and the British Orthopaedic Association patient-satisfaction score. The assessment was performed without the examiner knowing whether the patella had been resurfaced. At the time of follow-up, there were 474 knees. Thirty-five patients who had a bilateral knee replacement underwent resurfacing on one side only. Results: The overall prevalence of anterior knee pain was 25.1% (fifty-eight of 231 knees) in the nonresurfacing group, compared with 5.3% (thirteen of 243 knees) in the resurfacing group (p < 0.0001). There was one case of component loosening. Ten of eleven patients who underwent secondary resurfacing had complete relief of anterior knee pain. The overall postoperative knee scores were lower in the nonresurfacing group, and the difference was significant among patients with osteoarthritis (p < 0.01). There was no significant difference between the resurfacing and nonresurfacing groups with regard to the postoperative function score. Patients who had a bilateral knee replacement were more likely to prefer the resurfaced side. Conclusions: As the present study showed a significantly higher rate of anterior knee pain following arthroplasty without patellar resurfacing, we recommend patellar resurfacing at the time of total knee replacement when technically possible. Level of Evidence: Therapeutic study, Level I-1a (Randomized controlled trial [significant difference]). See Instructions to Authors for a complete description of levels of evidence.

セメントレスＴＫＡにおける膝蓋骨置換，非置換の検討

Thirty six knees in 30 patients treated by TKA with patellar resurfacing and 24 knees in 21 patients with patellar retention were clinically reviewed. 25 knees in 22 patients were rheumatoid arthritis, and 35 knees in 29 patients were osteoarthritis. The follow up period averaged 3 years. All patients were evaluated using the JOA score and Patellar score (Feller, 1996). In patients with osteoarthritis, there was no difference between the patellar resurfacing and retention group in clinical outcome. In patients with reumatoid arthritis, patellar resurfacing group had slightly better results than the retention group, but there was no difference between the two groups in activities of daily living. Radiographs showed no differences in prosthetic alignment and FTA. We did not find any significant benefit from resurfacing the patella during TKA in the medium term.

PATELLAR RESURFACING VERSUS RETENTION IN TOTAL KNEE ARTHROPLASTY

We studied 40 patients in whom the patella was not severely deformed and who were undergoing primary total knee arthroplasty (TKA) for osteoarthritis by one surgeon using one type of prosthesis. They were randomly allocated either to have the patella retained or resurfaced with a cemented, all-polyethylene component regardless of the state of the patellar articular cartilage. Apart from removal of osteophytes, no surgery was undertaken on the retained patellae. All 38 surviving patients were evaluated at three years using the HSS knee score and a new, specifically designed Patellar score (maximum score of 30). No TKA was revised, but two patients in the resurfacing group had a further unrelated procedure. The mean HSS and Patellar scores at follow-up were 89 and 28 in the patellar retention group and 83 and 26 in the patellar resurfacing group. Statistically significant lower scores for both were recorded in women and in heavier patients. Stair-climbing ability was significantly better in the retention group. Although there were no complications related to patellar resurfacing, in the medium term we did not find any significant benefit from resurfacing the patella during TKA for osteoarthritis if it was not severely deformed.