ObjectiveThere is an association between osteoarthritis-related pain severity and function, yet clear evidence about the sole influence of neuropathic-like symptoms on joint function and health-related quality of life (HRQoL) is lacking. Previous studies among knee OA patients show an association between neuropathic-like symptoms, lower functional status and lower quality of life, however analyses were unadjusted or had limited adjustment for influential covariates like pain intensity. The aim of this study was therefore to determine the influence of neuropathic-like symptoms—adjusted for multiple influential covariates—on joint-specific function and HRQoL in hip and knee OA patients.MethodsIn this observational study 255 patients (117 with hip OA and 138 with knee OA) completed the modified painDETECT questionnaire (mPDQ) to identify subjects with neuropathic-like symptoms (mPDQ score>12, possible neuropathic pain [NP] phenotype). The WOMAC and the RAND-36 were used to asses respectively function and HRQoL. Results were adjusted stepwise for age, sex and BMI (Model 1); back disorder, painful body regions, comorbidities and previous surgery (Model 2); and pain intensity and analgesic usage (Model 3).ResultsA possible NP phenotype was experienced by 37% of hip and 46% of knee OA patients. Final model 3 analysis revealed that hip OA patients with neuropathic-like symptoms scored significantly lower on pain-related aspects of HRQoL (ΔRAND-36 bodily pain: 6.8 points, p = 0.047) compared to patients with the unlikely NP phenotype. In knee OA patients, a possible NP phenotype was associated with diminished joint function (ΔWOMAC domains ranging 7.1 to 10.5 points, p<0.05) and more deficits on the physical functional aspect of HRQoL (ΔRAND-36 physical functioning: 6.8 points, p = 0.016).ConclusionNeuropathic-like symptoms deteriorate the subjective rating of pain-related quality of life in hip OA patients and significantly influence function in knee OA patients.

ObjectivesA key predictor for developing chronic residual pain after total knee or hip arthroplasty (TKA/THA) is sensitisation. Sensitisation can be defined as an ‘increased responsiveness of nociceptive neurons in the nervous system’. Aim of this study is to investigate the effects of preoperative treatment with duloxetine in sensitised knee and hip osteoarthritis (OA) patients on postoperative chronic residual pain up to 1 year after arthroplasty.SettingA multicentre, pragmatic, prospective, randomised clinical trial was conducted in three secondary care hospitals in the Netherlands.ParticipantsPatients with primary knee/hip OA who were planned for TKA/THA were screened using the modified painDETECT Questionnaire. Patients whose painDETECT score indicated that sensitisation may be present were eligible for participation. 111 participants were included and randomly assigned 1:1 to an intervention or control group. The intervention group received additional duloxetine treatment, the control group did not receive any additional treatment but was allowed to continue with any pain medication they were already taking.InterventionsPreoperative oral treatment for 7 weeks with 60 mg/day of duloxetine was compared with usual care.Primary and secondary outcome measuresPrimary outcome measure was pain at 6 months after arthroplasty, assessed with the Pain Subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) or the Hip disability and Osteoarthritis Outcome Score (HOOS) with a 0–100 scale. Secondary outcome measures were Visual Analogue Scale (VAS), and neuropathic-like pain measured using the modified PainDETECT Questionnaire. Longitudinal data collection included time points directly after duloxetine treatment, 1-day preoperatively, and 6 weeks, 6 months and 12 months postoperatively.ResultsMean improvement in the KOOS/HOOS pain subscale at 6 months postoperatively was 37 (SD 28.1) in the intervention group and 43 (SD 26.5) in the control group. No statistically significant difference was found in change score 6 months postoperatively between the two groups (p=0.280). 12 patients from the intervention group (21%) discontinued duloxetine due to adverse effects.ConclusionsPreoperative targeted treatment with duloxetine in end-stage knee and hip OA patients with sensitisation does not influence postoperative chronic residual pain after TKA/THA.Trial registration numberNTR4744.

T T RESULTS:Fair to good correlation coefficients were found for test-retest reliability of the total and activity scores (r = 0.49-0.81, intraclass correlation coefficient = 0.27-0.71). Standard error of measurement and minimal detectable change were large. For concurrent validity, weak to moderate correlation coefficients were found for total and activity scores (r = -0.07 to 0.54). Systematic bias was found between the IPAQ and accelerometer data, with higher scores on the IPAQ. T T CONCLUSION:Overall, the IPAQ showed fair reliability and weak concurrent validity. These results are in line with previous studies of the reliability and validity of the IPAQ. Due to systematic bias and large standard error of measurement and minimal detectable change, the IPAQ may only be suitable for intergroup comparisons.