Knee Injury and Osteoarthritis Outcome Score (KOOS) is available in over 30 languages and a commonly used Patient-Reported Outcome (PRO) for assessment of treatment effects following knee surgery. The aim of the study was to report the linguistic translational process and evaluate the psychometric properties of the Polish version of the KOOS questionnaire. We translated and culturally adapted the KOOS according to current guidelines for use in Poland. Patients who had undergone anterior cruciate ligament reconstruction (ACLR) completed the KOOS and Short Form 36 Health Survey (SF-36). We evaluated floor/ceiling effects, reliability (using Cronbach’s alpha, intraclass correlation coefficients (ICC) and measurement error), convergent and divergent construct validity (using four a priori stated hypotheses) and responsiveness (using data obtained prior to and one year after ACLR and described by both effect size (ES) and standardized response mean (SRM)). The clinical study population consisted of 72 subjects (mean age 29.8, 28% women). We did not observe floor effects in any KOOS subscales neither pre- nor postoperatively. As expected, ceiling effects were found postoperatively for the subscales Pain and ADL in this cohort assessed on average 1.3 year after surgery as more than 15% reported no pain or limitations in daily activities. The Cronbach’s alpha was above 0.9 for all subscales indicating excellent internal consistency. The test-retest reliability of all KOOS subscales at one-year postoperatively was excellent with ICCs exceeding 0.86 for all subscales. The minimal detectable change on group level ranged from 1.3 to 2.4, and on an individual level from 10.9 to 20.2. Responsiveness was demonstrated since the expected pattern of effect sizes between subscales following ACLR was found. We found the Polish version of the KOOS to be a valid and reliable instrument for use in patient groups having ACLR. We caution against monitoring individual patients since the smallest change considered clinically relevant cannot reliably be detected.

Objective To test the clinimetric properties and to evaluate the internal consistency, validity and reliability of the Polish version of the Knee injury and Osteoarthritis Outcome Score (KOOS) in older patients with end-stage knee osteoarthritis undergoing total knee replacement (TKR). Design and setting A prospective cohort study performed at the university hospital and the outpatient clinic. Methods The patients were asked to complete the KOOS questionnaire and the Short Form 36 Health Survey. We evaluated floor/ceiling effects, reliability (using Cronbach's α, intraclass correlation coefficients (ICC) and measurement error), structural validity (performing exploratory principal factor analysis), construct validity (with the use of 3 a priori hypotheses) and responsiveness (using data obtained before and after the surgery, and described by Global Perceived Effect, effect size and standardised response mean). Results The study consisted of 68 participants (mean age 68.8, 82% women). The floor effects were found prior to surgery for the subscales Sports and Recreation Function, and Quality of Life. The Cronbach's α was from 0.90 to 0.92 for all subscales, indicating excellent internal consistency. The test–retest reliability at follow-up was excellent, with ICCs ranging from 0.81 to 0.86 for all KOOS subscales. The minimal detectable change ranged from 18.2 to 24.3 on an individual level and from 2.4 to 2.9 on a group level. All KOOS items were relevant, and all a priori established hypotheses were supported. Responsiveness was confirmed with a statistically significant correlation between all KOOS subscales and the Global Perceived Effect score (ranging from 0.56 to 0.70, p<0.001). Conclusions The Polish version of KOOS demonstrated good reliability, validity and responsiveness for use in patient groups that had undergone TKR. Since the smallest change considered clinically relevant cannot reliably be detected in individual cases, the Polish version of KOOS is advocated for assessment of groups of patients.

Background: The Hip disability and Osteoarthritis Outcome Score (HOOS) is a frequently used patient-reported outcome measure (PROM) for assessment of hip disorders and treatment effects following hip surgery. The objective of the study was to translate and adapt the Hip disability and Osteoarthritis Outcome Score (HOOS) into Polish and to investigate the psychometric properties of the HOOS in patients with osteoarthritis undergoing total hip replacement (THR). Materials and methods: The Polish version of the HOOS was developed according to current guidelines. Patients completed the HOOS, Short Form 36 Health Survey (SF-36), the visual analogue scale (VAS) for pain and the global perceived effect (GPE) scale. Psychometric properties including interpretability (floor/ceiling effects), internal consistency (Cronbach’s alpha), test-retest reliability (intra-class correlation coefficient, ICC), convergent construct validity (a priori hypothesized Spearman’s correlations between the HOOS subscales, the generic SF-36 measure and the VAS for pain) and responsiveness (effect size, association between the HOOS and GPE scores) were analyzed. Results: The study included 157 patients (mean age 66.8 years, 54% women). Floor effects were found prior to THR for the HOOS subscales Sports and Recreation and Quality of Life. The Cronbach’s alpha was over 0.7 for all subscales indicating satisfactory internal consistency. The test–retest reliability was good for the HOOS subscale Pain (0.82) and excellent for all other subscales with ICCs ranging from 0.91 to 0.96. The minimal detectable change ranged from 12.0 to 26.2 on an individual level and from 1.4 to 3.0 on a group level. Seven out of eight a priori hypotheses were confirmed indicating good construct validity. Responsiveness was high since the expected pattern of effect sizes in all subscales was found. Conclusions: The Polish version of the HOOS demonstrated good reliability, validity and responsiveness for use in patient groups having THR.

Our objective was report short-term results of total hip replacement (THR) and to identify patients with functional recovery and with treatment failure. We also aimed to investigate whether there are any potential predicting factors for functional recovery or treatment failure. Prospective cohort study. Clinical examination was performed and data were collected from patients before THR and at three follow-up assessments within subsequent year. The primary endpoint was the change between assessments in the average score on four subscales of the Hip disability and Osteoarthritis Outcome Score (HOOS₄) covering pain, symptoms, activity of daily living, and quality of life. Secondary endpoints included results on all five HOOS subscales, and the SF–36. Functional Recovery and Treatment Failure were defined basing on the published reference population values. We assessed 179 patients (98 women and 81 men, mean age at THR 67 years, range 31–90 years). The mean HOOS₄ scores continued to improve up to 12 months after THR. Functional Recovery was identified in 32% while Treatment Failure in 16% of the patients. We found an association between high (>30.3) preoperative SF–36 Physical Component Summary scores and Functional Recovery, as well as low preoperative SF–36 Physical (<30.3) and Mental (<35.9) Component Summary scores and Treatment Failure. Knowing that only one third of subjects undergoing THR achieved Functional Recovery and one sixths had Treatment Failure, gives us a better perspective to discuss feasibility of expectations and, consequently, to prevent patient dissatisfaction following THR.

The associations between individual components of metabolic syndrome (MetS) and bone health in children are complex, and data on this topic are sparse and inconsistent. We assessed the relationship between bone turnover markers and markers of the processes underlying MetS (insulin resistance and inflammation) in a group of presumably healthy children aged 9–11 years: 89 (51 girls, 38 boys) presenting without any features of MetS and 26 (10 girls, 16 boys) with central obesity and two features of MetS. Concentrations of glucose, triglycerides (TG), HDL cholesterol (HDL-C), C-reactive protein (CRP), HbA1c, total 25-hydroxyvitamin D (25(OH)D), intact-P1NP (N-terminal propeptide of type I procollagen), CTX-1 (C-terminal telopeptide of type I collagen) were assayed and insulin resistance was assessed (HOMA-IR). BMI centile, waist circumference (WC) and blood pressure were measured. The presence of MetS in girls resulted in significantly lower concentrations of CTX-1 and a trend to lower CTX-1 in boys. The concentrations of bone formation marker i-P1NP were not affected. Among the features associated with MetS, HOMA-IR appeared as the best positive predictor of MetS in girls, whereas CRP was the best positive predictor in boys. A significant influence of HOMA-IR on the decrease in CTX-1 in girls was independent of BMI centile and WC, and the OR of having CTX-1 below the median was 2.8-fold higher/1SD increased in HOMA-IR (p = 0.003). A weak relationship between CTX-1 and CRP was demonstrated in girls (r = −0.233; p = 0.070). Although TG, as a MetS component, was the best significant predictor of MetS in both sexes, there were no correlations between bone markers and TG. We suggest that dyslipidemia is not associated with the levels of bone markers in prepubertal children whereas CRP is weakly related to bone resorption in girls. In prepubertal girls, insulin resistance exerts a dominant negative impact on bone resorption, independent of BMI centile and waist circumference.