Trajectories of body mass index from early adulthood to late midlife and incidence of total knee arthroplasty for osteoarthritis: findings from a prospective cohort study.

OBJECTIVE: To examine the association between body mass index (BMI) trajectories from early adulthood to late midlife and risk of total knee arthroplasty (TKA) for osteoarthritis. METHODS: 24,368 participants from the Melbourne Collaborative Cohort Study with weight collected during 1990-1994, 1995-1998, and 2003-2007, recalled weight at age 18-21 years, and height measured during 1990-1994 were included. Incident TKA from 2003 to 2007 to December 2018 was determined by linking cohort records to the National Joint Replacement Registry. RESULTS: Using group-based trajectory modelling, six distinct trajectories (TR) of BMI from early adulthood (age 18-21 years) to late midlife (approximately 62 years) were identified: lower normal to normal BMI (TR1; 19.7% population), normal BMI to borderline overweight (TR2; 36.7%), normal BMI to overweight (TR3; 26.8%), overweight to borderline obese (TR4; 3.5%), normal BMI to class 1 obesity (TR5; 10.1%), overweight to class 2 obesity (TR6; 3.2%). Over 12.4 years, 1,328 (5.4%) had TKA. The hazard ratios for TKA increased in all TR compared to TR1 [from TR2: 2.03 (95% CI 1.64-2.52) to TR6: 8.59 (6.44-11.46)]. 28.4% of TKA could be prevented if individuals followed the trajectory one lower, an average weight reduction of 8-12 kg from early adulthood to late midlife, saving $AUS 373 million/year. Most reduction would occur in TR2 (population attributable fraction 37.9%, 95% CI 26.7-47.3%) and TR3 (26.8%, 20.0-31.2%). CONCLUSIONS: Prevention of weight gain from young adulthood to late midlife in order to reduce overweight/obesity has the potential to significantly reduce the cost and burden of TKA.

Crosswalks between the Oxford hip and knee scores and the HOOS-12 and KOOS-12 instruments.

OBJECTIVE: To develop and validate bi-directional crosswalks between the Oxford Hip Score (OHS) and HOOS-12 summary impact score, and between the Oxford Knee Score (OKS) and KOOS-12 summary impact score. METHODS: Data were sourced from the Australian Orthopaedic Association National Joint Replacement Registry Patient-Reported Outcome Measures Program. Patients undergoing primary joint replacement for osteoarthritis who completed the OHS and HOOS-12 or OKS and KOOS-12 instruments were included in the analysis. An equipercentile method was used to create four crosswalks, with the distribution of scores smoothed using log-linear models prior to equating. Crosswalk validity was assessed through comparison of actual vs derived scores, Pearson correlation coefficients, root mean square errors (RMSE) and Bland-Altman plots. RESULTS: Paired OHS/HOOS-12 data and paired OKS/KOOS-12 data were available for 4,513 patients undergoing total hip replacement and 5,942 patients undergoing total knee replacement, respectively. Minimal differences were observed between actual and crosswalk-derived mean scores (actual OHS 27.55 vs derived OHS 27.56; actual HOOS-12 53.28 vs derived HOOS-12 53.31; actual OKS 27.34 vs derived OKS 27.34; actual KOOS-12 50.51 vs derived KOOS-12 50.58). High correlation was observed between actual and derived scores (Pearson's r for hip-specific instruments: 0.943-0.946; Pearson's r for knee-specific instruments: 0.925-0.931). Plotted actual vs mean derived scores also indicated robust concordance across the breadth of the instrument scales. CONCLUSION: These crosswalks provide close approximations of actual OHS, OKS, HOOS-12 and KOOS-12 scores, as indicated by multiple validation metrics. They offer a resource for clinicians, researchers and arthroplasty registries to support PROMs score conversion and data harmonisation efforts.

Performance of the HOOS-12 and KOOS-12 instruments for evaluating outcomes from joint replacement surgery.

OBJECTIVE: To evaluate the psychometric properties of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and Knee injury and Osteoarthritis Outcome Score (KOOS-12) for use in evaluating outcomes after joint replacement for osteoarthritis. DESIGN: Patient-reported outcomes data collected by the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. HOOS-12 and KOOS-12 domain (pain, function, quality of life) and summary impact data were available. The Oxford Hip Score (OHS), Oxford Knee Score (OKS) and EQ-5D-5L were used as comparators. Instruments were administered pre-operatively and at 6 months post-operatively. Internal consistency reliability, floor and ceiling effects, convergent validity, known groups validity, and responsiveness were evaluated using standard psychometric techniques. RESULTS: Baseline HOOS-12 and KOOS-12 data were available for 3,023 patients undergoing primary total hip replacement and 4,010 patients undergoing primary total knee replacement. At baseline, high internal consistency was demonstrated for all domains and summary scores (Cronbach's alpha: HOOS-12 = 0.81-0.93; KOOS-12 = 0.82-0.92). Post-operative ceiling effects (>15% of patients scoring the best possible score) were identified for the HOOS-12 pain (46%), function (39%) and quality of life domains (26%) and summary score (17%), and for the KOOS-12 pain (21%) and function domains (18%). The HOOS-12 and KOOS-12 could differentiate between two known groups (lowest/highest OHS or OKS quartiles post-operatively; p < 0.001) and were highly responsive to change (effect sizes for HOOS-12: 2.20-2.83; KOOS-12: 1.82-2.35). CONCLUSION: The HOOS-12 and KOOS-12 have good psychometric properties for capturing joint replacement outcomes including excellent responsiveness, although ceiling effects may limit monitoring of post-operative improvement.

Implications for research and clinical use from a Rasch analysis of the HOOS-12 and KOOS-12 instruments.

OBJECTIVE: To evaluate the structural validity of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and 12-item Knee injury and Osteoarthritis Outcome Score (KOOS-12) using Rasch analysis and consider psychometric implications for research and clinical use. METHOD: Individual-level HOOS-12 and KOOS-12 data from the Australian Orthopaedic Association National Joint Replacement Registry, collected before and after primary total hip and knee replacement, were used for this analysis. Using the Rasch analytic approach, overall model fit and item fit were examined, together with potential reasons for misfit including response threshold ordering, differential item functioning, internal consistency, unidimensionality and item targeting. RESULTS: Overall misfit to the Rasch model was evident for both instruments. A degree of item misfit was also observed, although most items demonstrated logical sequencing of response options. Only two items (hip/knee pain frequency and awareness of hip/knee problems) displayed disordered response thresholds. The pain, function, and quality of life domains of the HOOS-12 and KOOS-12 demonstrated excellent internal consistency reliability (person separation index: 0.80-0.93) and unidimensionality. A mismatch between item difficulty and person ability scores at the highest end of the HOOS-12 and KOOS-12 scales contributed to post-operative ceiling effects (mean logit for HOOS-12: 3.57; KOOS-12: 2.58; ≈0 indicates well-targeted scale). CONCLUSION: We found evidence to support the structural validity of the three HOOS-12 and KOOS-12 domains for evaluating joint replacement outcomes. However, there may be missing content in both instruments particularly for high-functioning patients. Minor refinement of some response options may be warranted to improve item performance.

Forecasting the future burden of opioids for osteoarthritis.

OBJECTIVE: To quantify the current national burden of opioids for osteoarthritis (OA) pain in Australia in terms of number of dispensed opioid prescriptions and associated costs, and to forecast the likely burden to the year 2030/31. DESIGN: Epidemiological modelling. METHODS: Published data were obtained on rates of opioid prescribing for people with OA and national OA prevalence projections. Trends in opioid dispensing from 2006 to 2016, and average costs for common opioid subtypes were obtained from the Pharmaceutical Benefits Scheme and Medicare Australia Statistics. Using these inputs, a model was developed to estimate the likely number of dispensed opioid prescriptions and costs to the public healthcare system by 2030/31. RESULTS: In 2015/16, an estimated 1.1 million opioid prescriptions were dispensed in Australia for 403,954 people with OA (of a total 2.2 million Australians with OA). Based on recent dispensing trends and OA prevalence projections, the number of dispensed opioid prescriptions is expected to nearly triple to 3,032,332 by 2030/31, for an estimated 562,610 people with OA. The estimated cost to the Australian healthcare system was $AUD25.2 million in 2015/16, rising to $AUD72.4 million by 2030/31. CONCLUSION: OA-related opioid dispensing and associated costs are set to increase substantially in Australia from 2015/16 to 2030/31. Use of opioids for OA pain is concerning given joint disease chronicity and the risk of adverse events, particularly among older people. These projections represent a conservative estimate of the full financial burden given additional costs associated with opioid-related harms and out-of-pocket costs borne by patients.

Prevalence of arthritis according to age, sex and socioeconomic status in six low and middle income countries: analysis of data from the World Health Organization study on global AGEing and adult health (SAGE) Wave 1.

BACKGROUND: In higher income countries, social disadvantage is associated with higher arthritis prevalence; however, less is known about arthritis prevalence or determinants in low to middle income countries (LMICs). We assessed arthritis prevalence by age and sex, and marital status and occupation, as two key parameters of socioeconomic position (SEP), using data from the World Health Organization Study on global AGEing and adult health (SAGE). METHODS: SAGE Wave 1 (2007-10) includes nationally-representative samples of older adults (≥50 yrs), plus smaller samples of adults aged 18-49 yrs., from China, Ghana, India, Mexico, Russia and South Africa (n = 44,747). Arthritis was defined by self-reported healthcare professional diagnosis, and a symptom-based algorithm. Marital status and education were self-reported. Arthritis prevalence data were extracted for each country by 10-year age strata, sex and SEP. Country-specific survey weightings were applied and weighted prevalences calculated. RESULTS: Self-reported (lifetime) diagnosed arthritis was reported by 5003 women and 2664 men (19.9% and 14.1%, respectively), whilst 1220 women and 594 men had current symptom-based arthritis (4.8% and 3.1%, respectively). For men, standardised arthritis rates were approximately two- to three-fold greater than for women. The highest rates were observed in Russia: 38% (95% CI 36%-39%) for men, and 17% (95% CI 14%-20%) for women. For both sexes and in all LMICs, arthritis was more prevalent among those with least education, and in separated/divorced/widowed women. CONCLUSIONS: High arthritis prevalence in LMICs is concerning and may worsen poverty by impacting the ability to work and fulfil community roles. These findings have implications for national efforts to prioritise arthritis prevention and management, and improve healthcare access in LMICs.

Return to sport matters-longer-term quality of life after ACL reconstruction in people with knee difficulties.

Many individuals experience long-term quality of life (QOL) impairment following anterior cruciate ligament reconstruction (ACLR). Factors contributing to poor QOL and psychological health >5 years after ACLR remain unclear. This study aimed to describe QOL and psychological health outcomes in people with knee difficulties (pain, symptoms, or functional limitations) 5-20 years following ACLR and identify factors explaining variability in these outcomes. Participants with knee difficulties 5-20 years following ACLR completed a battery of validated patient-reported outcomes [including the Knee injury and Osteoarthritis Outcome Score (KOOS), ACL-QOL, and the Assessment of QOL (AQoL-8D) instrument]. Multivariable linear regression was used to identify factors explaining variability in outcomes. One hundred sixty-two participants aged 38 ± 9 (mean ± SD) years completed questionnaires 9 ± 4 (range 5-20) years following ACLR. Thirty-nine percent of participants returned to competitive sport, 28% returned to a lower level, and 32% did not return to sport after ACLR. Not returning to sport after ACLR was associated with worse KOOS-QOL (ß = 0.29, P = 0.001 [mean ± SD (55 ± 20)], ACL-QOL [ß = 0.48, P < 0.001; (57 ± 21)], and AQoL-8D [ß = 0.22, P = 0.02 (0.80 ± 0.14)]) scores. Increased body mass index (56% were overweight/obese) was related to worse QOL and more depressive symptoms. Subsequent knee surgery and contralateral ACLR were also associated with poorer QOL outcomes in these individuals.

Substantial rise in the lifetime risk of primary total knee replacement surgery for osteoarthritis from 2003 to 2013: an international, population-level analysis.

OBJECTIVE: To estimate and compare the lifetime risk of total knee replacement surgery (TKR) for osteoarthritis (OA) between countries, and over time. METHOD: Data on primary TKR procedures performed for OA in 2003 and 2013 were extracted from national arthroplasty registries in Australia, Denmark, Finland, Norway and Sweden. Life tables and population data were also obtained for each country. Lifetime risk of TKR was calculated for 2003 and 2013 using registry, life table and population data. RESULTS: Marked international variation in lifetime risk of TKR was evident, with females consistently demonstrating the greatest risk. In 2013, Finland had the highest lifetime risk for females (22.8%, 95%CI 22.5-23.1%) and Australia had the highest risk for males (15.4%, 95%CI 15.1-15.6%). Norway had the lowest lifetime risk for females (9.7%, 95%CI 9.5-9.9%) and males (5.8%, 95%CI 5.6-5.9%) in 2013. All countries showed a significant rise in lifetime risk of TKR for both sexes over the 10-year study period, with the largest increases observed in Australia (females: from 13.6% to 21.1%; males: from 9.8% to 15.4%). CONCLUSIONS: Using population-based data, this study identified significant increases in the lifetime risk of TKR in all five countries from 2003 to 2013. Lifetime risk of TKR was as high as 1 in 5 women in Finland, and 1 in 7 males in Australia. These risk estimates quantify the healthcare resource burden of knee OA at the population level, providing an important resource for public health policy development and healthcare planning.

Quality of life in anterior cruciate ligament-deficient individuals: a systematic review and meta-analysis.

BACKGROUND: Physical and psychological impairments impacting quality of life (QOL) are common following ACL reconstruction. Rehabilitation alone is an effective alternative to reconstruction for some patients, warranting the investigation of QOL in ACL-deficient individuals. PURPOSE: To report and compare QOL in ACL-deficient individuals with population norms and ACL-reconstructed groups, and investigate relationships between participant characteristics and QOL. STUDY DESIGN: Systematic review and meta-analysis. METHODS: We systematically identified and methodologically appraised all studies reporting QOL in ACL-deficient individuals ≥5 years following ACL rupture. Knee-related and health-related QOL scores in ACL-deficient cohorts were compared to ACL-reconstructed groups using a random-effects meta-analysis. Descriptive comparisons were made with population norms. RESULTS: Eleven studies reported QOL in 473 ACL-deficient individuals, a mean of 10 (range 5-23) years following ACL rupture. Eight studies reported knee-related QOL using the Knee injury and Osteoarthritis Outcome Score QOL subscale (KOOS-QOL); scores (mean±SD) ranging from 54±17 to 77±22 were impaired compared to population norms. Health-related QOL, measured with the SF-36 domain scores in five studies, was similar to population norms, but impaired compared to physically active populations. Meta-analysis revealed no significant differences in KOOS-QOL (mean difference (95% CI) 2.9 (-3.3 to 9.1)) and SF-36 scores (for all SF-36 domains except Vitality) between ACL-deficient and ACL-reconstructed groups. CONCLUSIONS: This systematic review found impaired knee-related QOL in ACL-deficient individuals ≥5 years after ACL rupture, compared to population norms. Meta-analysis revealed similar knee-related QOL in ACL-deficient and ACL-reconstructed groups, and no difference in health-related QOL scores for seven of the eight SF-36 domains.

The substantial personal burden experienced by younger people with hip or knee osteoarthritis.

OBJECTIVE: To compare Health-Related Quality of Life (HRQoL) and psychological distress in younger people with hip or knee osteoarthritis (OA) to age- and sex-matched population norms, and evaluate work limitations in this group. METHOD: People aged 20-55 years with hip or knee OA were recruited from major hospitals (n = 126) and community advertisements (n = 21). HRQoL was assessed using the Assessment of Quality of Life (AQoL) instrument (minimal important difference 0.06 AQoL units) and compared to population norms. Psychological distress was assessed using the Kessler Psychological Distress Scale (K10) and the prevalence of high/very high distress (K10 score ≥22) was compared to Australian population data. Work limitations were evaluated using the Workplace Activity Limitations Scale (WALS). RESULTS: Considering most participants had a relatively recent OA diagnosis (<5 years), the extent of HRQoL impairment was unexpected. A very large reduction in HRQoL was evident for the overall sample, compared with population norms (mean difference -0.35 AQoL units, 95% CI -0.40 to -0.31). Females, people aged 40-49 years, and those with hip OA reported average HRQoL impairment of almost 40% (mean reductions -0.38 to -0.39 AQoL units). The overall prevalence of high/very high distress was 4 times higher than for the population (relative risk 4.19, 95% CI 3.53-4.98) and 67% reported moderate to considerable OA-related work disability, according to WALS scores. CONCLUSIONS: These results clearly demonstrate the substantial personal burden experienced by younger people with hip or knee OA, and support the provision of targeted services to improve HRQoL and maximise work participation in this group.