Different influence of Ti, PMMA, UHMWPE, and Co-Cr particles on peripheral blood monocytes during periprosthetic inflammation.

This study investigated cellular trafficking and inflammatory markers in orthopedic biomaterial particle-challenged human peripheral blood monocytes (PBMCs) using a murine immunodeficiency (SCID) model. Periprosthetic tissues from aseptic loosening patients were transplanted into muscles of SCID mice. PBMCs from the same patients were stimulated in vitro with Ti-6Al-4V, PMMA, UHMWPE, or Co-Cr particles for 3 days before administered intraperitoneally to the periprosthetic tissue-implanted mice. The xenografts were harvested 2 weeks later for histological and molecular analyses. Significant cell infiltration was obvious in the transplanted tissues from mice transfused with Ti-alloy, PMMA and UHMWPE-provoked PBMCs compared to controls, and UHMWPE-provoked PBMCs group accumulated significantly more cells among all groups. There were ubiquitous TRAP+ stained cells in all xenografts from particle-stimulated PBMCs mice. Immunohistochemical staining indicated that significantly more IL-1ß and TNF positive cells occurred in Ti and PMMA groups; while the UHMWPE group resulted in stronger positive MCP-1 and IL-6 stains. Polymerase chain reaction (PCR) confirmed overexpression of both IL-1ß and TNF in Ti and PMMA-stimulated groups; and more MIP-1α gene expression developed in the UHMWPE group. Overall, different type of orthopedic materials influenced the trafficking ability of particle-activated PBMCs which may depend on upregulation of various proinflammatory cytokines and chemokines.

Revision total hip arthroplasty using a modular femoral implant in Paprosky type III and IV femoral bone loss.

The purpose of this study was to compare results of patients with Paprosky type I and II femoral defects vs type IIIA, IIIB, and IV defects in patients undergoing revision hip arthroplasty. There were 64 patients in the group with type I and II defects with an average age of 68 years. There were 52 patients with Paprosky type IIIA, IIIB, and IV defects with an average age of 67 years. There were 8 intraoperative fractures in the type III and IV group, whereas there were 9 in the type I and II group. There were no differences between the 2 groups with respect to subsidence, loosening, dislocation, infection, and medical complications. Survivorship for the whole group was 96.9% at 5 years. Modular femoral implants provide several intraoperative options to restore leg length, offset, and stability despite femoral defects. We did not realize a higher failure rate in patients with type III or IV defects.

Quadriceps muscle function in primary total knee arthroplasty.

Patient expectations after primary total knee arthroplasty (TKA) continue to increase as the arthroplasty population becomes younger. Patients desire more than just pain relief, function, and the ability to return to higher level activities after TKA. Quadriceps muscle function and strength are critical determinants of this outcome. Many factors, including patient specific issues, surgical technique, and implant design, affect this function after TKA. This article will review our current understanding of quadriceps muscle function after TKA and the factors under the surgeon's control to achieve the best outcome.

The effect of obesity on quality-of-life improvement after total knee arthroplasty.

Obesity has been consistently implicated as a major risk factor in the development and progression of osteoarthritis (OA), and total joint arthroplasty (TJA) has emerged as one of the most efficacious and cost-effective OA treatments. The effectiveness of this treatment manifests itself in both clinical and quality of life (QOL) measures. Given the interrelatedness of obesity and OA, and given the success of TJA in improving QOL, we conducted a study to determine whether obesity would adversely affect QOL improvement in 50 patients who underwent primary total knee arthroplasty for primary knee OA. Our results show that, 6 months after surgery, QOL measures improved more for obese patients than for overweight patients and patients with ideal body weight.

Capturing the full measure of patient outcome improvement using a self-assessed health adjustment.

RATIONALE: Self-assessed health (SAH) status is a very simple four-, or five-category self-reported measure of health status that has been shown to be a powerful predictor of mortality, service use and total cost of medical care treatment. It is therefore reasonable to suggest that pre-intervention SAH may influence the extent to which patient outcomes improve following surgery. METHODS: Using the four-category measure of SAH of Excellent; Good; Fair; Poor, we developed an adjustment factor based on the mean improvement of the SAH category relative to the mean improvement of the overall sample. RESULTS: The results clearly indicate that the higher patients rated their pre-operative health, the greater their pre-post-operative improvement. Adjusting the outcome improvement by this SAH factor provides for the adjustment of the overall sample results by extent to which each category of SAH contributes to the overall mean. CONCLUSION: The results indicate that by adjusting patient outcome improvement measures by a factor based on pre-intervention SAH, overall sample patient outcome improvement increased 5.8%. The results also indicate that failure to adjust for pre-intervention SAH will result in an understatement of patient outcome improvement following surgery.

Using self-assessed health to predict patient outcomes after total knee replacement.

Self-assessed health status has been shown to be a powerful predictor of mortality, service use, and total cost of medical care treatment. We investigated the potential for self-assessed health to further serve as a predictor of improvement in health status after a clinical intervention. Using the five-category measure of self-assessed health (excellent, very good, good, fair, or poor), we examined patients' improvements in health status after total knee arthroplasty in each of the WOMAC-defined categories for health status in patients. The results indicate that the greater patients rated their preoperative health, the greater their postoperative improvement. The results suggest that a simple process of asking patients to rate their own health in a presurgery clinic could be a powerful tool in predicting patient outcome. This also suggests that by stratifying preoperative self-assessed health, potential improvements in health status will be more fully captured.

Selecting a subjective health status measure for optimum utility in everyday orthopaedic practice.

BACKGROUND: The time required to complete patient outcome questionnaires such as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Short Form General Health Survey (SF-36) and the Musculoskeletal Function Assessment (MFA) can sometimes threaten elderly, compromised patients sufficiently to compromise compliance with follow-up clinics. Incomplete questionnaires can also present problems of data bias. A little used (in the USA), patient-friendly questionnaire, the Nottingham Health Profile (NHP) has the potential to reduce the statistical and practical problems associated with the more generally used instruments. We hypothesized that NHP will produce similar results to WOMAC and SF-36 and is more sensitive to small changes in patient outcomes than SF-36 and MFA. METHOD: Twenty-three patients blindly completed WOMAC, SF-36 and NHP questionnaires. Spearman's Rank Order Correlation was used to compare the component scores of each instrument. Simulation of the before and after results of 10 fictitious patient comparing MFA and NHP was conducted using the related sample t-test. RESULTS: Seven of nine correlation coefficients were statistically significant and ranged from 0.711 to 0.901. The significance of the before and after difference on the five-point scale response was P = 0.05 when the NHP was used and P = 0.07 when MFA was used. The before and after difference on 'yes-no' response questions was P < 0.001 when NHP was used but showed no difference when the MFA was used. CONCLUSIONS: Our hypothesis was supported and we suggest that NHP can be used with confidence as an alternative to other patient outcome instruments.