Psychosocial Determinants of Total Knee Arthroplasty Outcomes Two Years After Surgery.

OBJECTIVE: To evaluate the association of preoperative psychosocial and demographic factors with total knee arthroplasty (TKA) outcomes and satisfaction in patients with osteoarthritis (OA) of the knee at 24 months after surgery. METHODS: A prospective cohort study of patients undergoing TKA was conducted. Outcome measures included: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form 36 (SF-36) scores at baseline and 24 months after surgery, and patient satisfaction with TKA at 24 months. Linear regression models were performed to evaluate the association of preoperative psychosocial determinants (ie, Medical Outcome Study Social Support Scale; Depression, Anxiety, and Stress Scale; Brief COPE inventory, The Life Orientation Test-Revised; Multidimensional Health Locus of Control; and Arthritis Self-Efficacy Scale) on outcomes. RESULTS: We included 178 patients. Increasing WOMAC pain scores at 24 months were associated with increasing age and body mass index (BMI); low tangible social support and low optimism were associated with higher levels of pain (R2 = 0.15). A decrease in WOMAC function scores was also associated with older age and higher BMI; low tangible support, increased stress, and low optimism were also associated with worse function (R2 = 0.22). When evaluating quality of life, lower SF-36 physical functioning scores at 24 months were associated with age, high BMI, and comorbidity (R2 = 0.34). Lower SF-36 mental functioning scores were associated with depression and low optimism (R2 = 0.38). Having a dysfunctional style of coping was associated with lower satisfaction with surgery after 24 months (adjusted R2 = 0.12). CONCLUSION: Psychosocial factors, such as tangible support, depression, dysfunctional coping, and optimism, were associated with pain, function, and satisfaction 2 years after TKA. Perioperative programs identifying and addressing psychosocial problems may result in improvements in pain and function after TKA.

Effect of Body Mass Index and Psychosocial Traits on Total Knee Replacement Costs in Patients with Osteoarthritis.

OBJECTIVE: Clinical and psychosocial attributes are associated with clinical outcomes after total knee replacement (TKR) surgery in patients with osteoarthritis (OA), but their relationship with TKR-related costs is less clear. Our objective was to evaluate the effect of clinical and psychosocial attributes on TKR costs. METHODS: We conducted a 6-month prospective cohort study of patients with knee OA who underwent TKR. We examined baseline demographic, clinical [body mass index (BMI) and comorbidities], and psychosocial attributes (social support, locus of control, coping, depression, anxiety, stress, and self-efficacy); baseline and 6-month OA clinical outcomes [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function]; and 6-month direct and indirect TKR-related costs. Multiple regression was performed to identify determinants of TKR-related costs. RESULTS: We included 212 patients; 66% were women, 71% were white, and the mean age was 65.2 years. The mean baseline WOMAC pain score was 55 (SD 19) and WOMAC function score was 54 (SD 20). Mean total TKR-related costs were US$30,831 (SD $9893). Multivariate regression analyses showed that increasing BMI and anxiety levels and decreasing levels of positive social interactions were associated with increased costs. A lower cost scenario with a lower range of normal BMI (19.5), highest positive social interaction, and no anxiety predicted TKR costs to be $22,247. Predicted costs in obese patients (BMI 36) with lowest positive social interaction and highest anxiety were $58,447. CONCLUSION: Increased baseline BMI, anxiety, and poor social support lead to higher TKR-related costs in patients with knee OA. Preoperative interventions targeting these factors may reduce TKR-related costs, and therefore be cost-effective.

Reliability and clinically important improvement thresholds for osteoarthritis pain and function scales: a multicenter study.

OBJECTIVE: To assess the reliability and clinically meaningful thresholds of intermittent and constant osteoarthritis pain (ICOAP) score, the Knee injury and Osteoarthritis Outcome Score Physical function Short-form (KOOS-PS), the Hip disability and Osteoarthritis Outcome Score Physical function Short-form (HOOS-PS), and the Quality of life subscales of HOOS/KOOS (HOOS-QOL/KOOS-QOL) in patients with knee or hip arthritis. METHODS: One hundred and ninety-five patients (141 knee, 54 hip) seen at 2 orthopedic outpatient clinics with a diagnosis of knee or hip OA completed patient-reported questionnaires (ICOAP pain scale, KOOS-PS, HOOS-PS, KOOS-QOL, HOOS-QOL) at baseline and 2-week followup. Reliability was assessed using intraclass correlation coefficients (ICC). We calculated minimum clinically important difference (MCID) and moderate improvement in the subgroup that reported change in the status of their affected joint. RESULTS: The reliability as assessed by ICC was as follows: ICOAP pain scale, 0.63 (0.48, 0.74) in patients with knee arthritis, and 0.86 (0.73, 0.93) for hip arthritis; KOOS-PS, 0.66 (0.52, 0.77); HOOS-PS, 0.82 (0.66, 0.91); KOOS-QOL, 0.79 (0.69, 0.86); and HOOS-QOL, 0.67 (0.42, 0.83). MCID and moderate improvement estimates in patients with knee arthritis were ICOAP pain scale, 18.5 and 26.7; KOOS-PS, 2.2 and 15.0; and KOOS-QOL, 8.0 and 15.6. A smaller sample in patients with hip arthritis precluded MCID and moderate improvement estimates. CONCLUSION: We found that ICOAP pain and KOOS-PS/HOOS-PS scales were reasonably reliable in patients with hip OA. Reliability of these scales was much lower in patients with knee arthritis. Thresholds for clinically meaningful change in pain or function on these scales were estimated for patients with knee arthritis.

Cost-effectiveness of total knee replacement: a prospective cohort study.

OBJECTIVE: Total knee replacement (TKR) rates have significantly increased in the past decade. While the procedure itself might be costly, the cost-effectiveness and potential offset costs from patient and societal benefits have not been clearly established. The objective of this study was to perform an economic evaluation of TKR in patients with knee osteoarthritis (OA). METHODS: We conducted a 6-month prospective cohort study of 212 patients with knee OA who underwent TKR at a single hospital in Houston, Texas. We included patient-level data from hospital billing databases and the patients' self-reported direct and indirect costs. The clinical outcome measure was pain and function measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire; we used the minimum clinically important difference (MCID; ≥20-point change) and the WOMAC 20% (WOMAC20), 50% (WOMAC50), and 70% (WOMAC70) relative improvement criteria. Incremental cost-effectiveness ratios were estimated using direct and indirect costs and WOMAC improvement. A societal perspective was used and multiple sensitivity analyses were performed to assess the robustness of the principal analysis. RESULTS: The total incremental cost per TKR was $20,133. The incremental cost-effectiveness ratios (ICERs) for improvement at 6 months were $33,345, $25,255, $35,274, and $56,908 for the MCID, WOMAC20, WOMAC50, and WOMAC70, respectively. Best- and worst-case scenario sensitivity analyses did not have a significant impact on the ICERs. Patient time lost was the most influential variable in the multiway sensitivity analysis. CONCLUSION: TKR is an effective intervention in reducing pain and improving functional status among patients with knee OA and is cost effective at both low and high levels of improvement.

Psychosocial determinants of outcomes in knee replacement.

OBJECTIVE: To identify potential psychosocial and educational barriers to clinical success following knee replacement. PATIENTS AND METHODS: The authors evaluated 241 patients undergoing total knee replacement, preoperatively and 6 months after surgery. Outcomes included the Western Ontario McMaster (WOMAC) scale and the Knee Society rating system (KSRS). Independent variables included: the medical outcome study-social support scale; depression, anxiety and stress scale; brief COPE inventory; health locus of control; arthritis self-efficacy scale and the life orientation test-revised. Multiple regression models evaluated associations of baseline demographic and psychosocial variables with outcomes at 6 months, controlling for body mass index, comorbidities and baseline outcome scores. RESULTS: Patients' mean age was 65 ± 9 years; 65% were women. Most patients improved outcomes after surgery. Several psychosocial variables were associated with outcomes. Regression analyses indicated lower education, less tangible support, depression, less problem-solving coping, more dysfunctional coping, lower internal locus of control were associated with worse WOMAC scores (R(2) contribution of psychosocial variables for pain 0.07; for function, 0.14). Older age, lower education, depression and less problem-solving coping were associated with poorer total KSRS scores (R(2) contribution of psychosocial variables to total KSRS model 0.09). Psychosocial variables as a set contributed from 25% to 74% of total explained variance across the models tested. CONCLUSION: Patients' level of education, tangible support, depression, problem-solving coping, dysfunctional coping and internal locus of control were associated with pain and functional outcomes after knee replacement. The findings suggest that, in addition to medical management, perioperative psychosocial evaluation and intervention are crucial in enhancing knee replacement outcomes.

In vivo efficacy of antimicrobial-coated devices.

BACKGROUND: Since device colonization is a prelude to infection, an antimicrobial-coated device that reduces bacterial colonization can potentially protect against infection. The objective of this animal study was to assess the efficacy of a coating with minocycline and rifampin to prevent colonization of a grit-blasted titanium implant and subsequent osteomyelitis. METHODS: Twenty-five rabbits underwent implantation of a titanium-alloy pin, either coated with minocycline and rifampin (thirteen rabbits) or uncoated (twelve rabbits), into the right femoral medullary canal. The implanted devices were inoculated with 500 CFU (colony-forming units) of Staphylococcus aureus prior to wound closure. The rabbits were killed one week later, and the removed device, femoral bone, a specimen obtained by swabbing the track surrounding the device, and blood were cultured. The rates of device colonization, osteomyelitis, and device-related osteomyelitis were compared between the two groups of rabbits. RESULTS: The antimicrobial-coated devices had a significantly lower rate of colonization than the uncoated devices (five of thirteen compared with twelve of twelve, p = 0.0016) and were associated with significantly lower rates of osteomyelitis (six of thirteen compared with twelve of twelve, p = 0.005) and device-related osteomyelitis (five of thirteen compared with twelve of twelve, p = 0.0016). Bacteremia did not develop in any rabbit. CONCLUSIONS: Orthopaedic devices coated with minocycline and rifampin significantly protected against device colonization and infection due to Staphylococcus aureus in this in vivo rabbit model. CLINICAL RELEVANCE: It is possible that orthopaedic devices coated with this unique combination of antimicrobial agents may protect against the development of clinical infection in humans.