Osteoarthritis of the knee is a chronic joint disorder characterised by progressive changes in articular cartilage, subchondral bone, synovium and surrounding structures. Its principal manifestations include pain, stiffness, restricted movement and difficulty performing daily activities. Hunter and Bierma-Zeinstra (2019) [1] described osteoarthritis as a disorder involving the whole joint, with interacting mechanical, biological and inflammatory processes. Knee involvement is particularly disabling because the joint plays an essential role in weight-bearing, walking and maintaining independence. Consequently, assessment of knee osteoarthritis requires consideration of functional limitations alongside clinical and radiological findings. The worldwide burden of knee osteoarthritis has increased with population ageing and the growing prevalence of obesity. Safiri et al. (2020) [2] demonstrated a substantial global burden of osteoarthritis and associated disability, highlighting its importance as a public health concern. Cui et al. (2020) [3] reported a pooled global prevalence of knee osteoarthritis of 22.9% among individuals aged 40 years and older. Their analysis identified increasing age and female sex as important associated factors. These findings emphasise the need to identify vulnerable populations and characterise factors associated with poor functional outcomes. In India, knee osteoarthritis presents an important challenge because of its effects on mobility, occupational performance and daily activities. Pal et al. (2016) [4] reported a prevalence of 28.7% in their community-based study and identified associations with female sex, obesity and increasing age. Occupational and household activities involving repeated knee loading may also be relevant when evaluating individual exposure profiles. However, associations observed in community populations cannot automatically be interpreted as determinants of disability among patients with established disease. A focused assessment of affected patients is therefore necessary to understand the relationship between demographic characteristics, clinical features and functional limitations. Functional disability may manifest as difficulty climbing stairs, rising from a chair, walking, shopping and undertaking household activities. Measuring these limitations provides information directly relevant to patients’ independence and rehabilitation needs. Kolasinski et al. (2020) [5] emphasised exercise, weight reduction in overweight or obese patients, and self-management as important components of knee osteoarthritis care. Evaluating potentially modifiable characteristics alongside pain and structural severity can help identify patients requiring targeted support. The present study was therefore undertaken to describe selected risk-factor profiles and examine their associations with functional disability among patients with knee osteoarthritis. AIM To assess selected risk-factor profiles and their association with functional disability among patients with knee osteoarthritis. OBJECTIVES • To describe the demographic, anthropometric, occupational and clinical characteristics of patients with knee osteoarthritis. • To assess functional disability using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale. • To determine the associations of selected demographic and clinical factors, pain intensity and radiological severity with functional disability.

Source of Data Data were obtained from patients with knee osteoarthritis attending the Orthopaedics outpatient department of MIMSR Medical college, Latur. Primary data were collected through participant interviews, anthropometric measurements, clinical examination and functional assessment. Relevant information regarding diagnosis, previous treatment, comorbidities and radiological findings was obtained from available medical records and knee radiographs. Study Design The study was conducted as a hospital-based analytical cross-sectional study involving 200 patients with knee osteoarthritis. Exposure characteristics, clinical severity and functional disability were assessed during a single study visit. No longitudinal follow-up was undertaken. The individual patient constituted the unit of analysis. Study Location The study was conducted in the Department of Orthopaedics at department of MIMSR Medical college, Latur providing outpatient assessment and treatment for patients with musculoskeletal disorders. Study Duration The study was conducted over 12 months. This period included participant recruitment, clinical assessment, data entry, verification and statistical analysis. Sample Size The study included 200 patients. It supports descriptive estimation of proportions and does not establish adequate power for every association or regression coefficient. A calculation based specifically on mean functional disability would require an anticipated WOMAC standard deviation and the desired precision. Sampling Technique Consecutive eligible patients attending the outpatient department during the study period were recruited until the required sample size was achieved. A screening register was maintained to document eligibility, participation and reasons for exclusion or refusal. Inclusion Criteria 1. Patients aged 40 years or older. 2. Patients with symptomatic knee osteoarthritis confirmed by clinical assessment and radiographic evidence of definite osteoarthritis, defined as Kellgren-Lawrence grade 2 or higher in at least one knee. 3. Patients with unilateral or bilateral knee involvement. 4. Patients who provided written informed consent. 5. Patients who could complete the study assessments independently or with standardised interviewer assistance. Exclusion Criteria 1. Patients with inflammatory arthritis, including rheumatoid arthritis or other inflammatory arthropathies. 2. Patients with suspected or confirmed septic arthritis, or an acute crystal arthritis episode affecting the knee. 3. Patients with an acute lower-limb fracture or recent significant knee injury that independently affected functional assessment. 4. Patients with previous knee arthroplasty in the knee selected for assessment. 5. Patients with major neurological or other musculoskeletal disorders that predominantly accounted for their mobility limitation. 6. Patients with severe cognitive impairment or acute illness that prevented valid participation in the interview and functional assessment. Procedure and Methodology Ethical considerations: Institutional Ethics Committee approval was obtained before recruitment. Participants were informed about the study purpose, procedures, voluntary participation and confidentiality measures. Written informed consent was obtained before assessment. Clinical history: A structured interview recorded age, sex, residence, education, occupation, symptom duration, laterality, previous knee injury, family history of osteoarthritis and relevant comorbidities. Smoking, tobacco use, current physical activity and previous treatment were documented. Occupational exposure was recorded in terms of years of work and usual time spent squatting, kneeling, climbing stairs, standing and carrying heavy loads. Previous occupational exposures were distinguished from current activity, which could have been reduced because of knee symptoms. Anthropometric assessment: Weight was measured using a calibrated weighing scale with participants wearing light clothing and no footwear. Height was measured using a stadiometer. BMI was retained as a continuous variable for the primary analysis. Any descriptive BMI categories were defined explicitly before analysis. Clinical examination: Both knees were examined for tenderness, crepitus, swelling, bony enlargement, deformity and restricted movement. Knee range of motion was assessed using a goniometer. Gait abnormalities and the use of walking aids were recorded. Pain assessment: Knee pain over the preceding week was assessed using an 11-point numerical rating scale, ranging from 0, indicating no pain, to 10, indicating the worst imaginable pain. Radiological assessment: Standardised weight-bearing anteroposterior and lateral knee radiographs were assessed using the Kellgren-Lawrence grading system. Among eligible patients, grades 2, 3 and 4 represented increasing radiographic severity. Radiological grading was performed without knowledge of the participant’s functional disability score. Selection of the index knee: For unilateral disease, the affected knee was selected. For bilateral disease, the more painful knee was selected; when pain scores were equal, the knee with the higher radiographic grade was selected. A predefined right-knee rule resolved any remaining tie. Each participant contributed one analytical record, and bilateral involvement was recorded separately. Functional disability assessment: Functional status was assessed using an authorised, validated language version of the WOMAC questionnaire. The Likert version comprised pain, stiffness and physical function domains. The physical function domain included 17 items scored from 0 to 4, giving a total score ranging from 0 to 68, with higher scores indicating greater functional limitation. Pain and stiffness domain scores were recorded separately. Arbitrary mild, moderate and severe disability categories were not applied without a validated basis. Missing questionnaire items were handled according to the instructions for the selected WOMAC version. Sample Processing No biological specimens were collected specifically for the study because the principal assessments were clinical, radiological and questionnaire-based. Therefore, laboratory specimen processing was not applicable. Results of investigations performed for routine clinical care were reviewed only when relevant to eligibility or comorbidity documentation. Completed questionnaires and examination forms were checked for completeness, assigned unique study codes and entered into a password-protected database. Radiographs and clinical records were linked using these codes. Identifying information was stored separately from the analytical dataset. Statistical Methods Data were analysed using SPSS 28.0 version. Continuous variables were assessed using histograms, Q-Q plots and the Shapiro-Wilk test. Approximately normally distributed variables were summarised as mean and standard deviation; skewed variables were presented as median and interquartile range. Categorical variables were expressed as frequencies and percentages. Estimates were accompanied by 95% confidence intervals where appropriate. Functional disability scores were compared between two independent groups using Welch’s independent-samples t-test when distributional assumptions were reasonable, or the Mann-Whitney U test otherwise. Comparisons across more than two groups were performed using ANOVA or Welch’s ANOVA, as appropriate, or the Kruskal-Wallis test for markedly skewed data. Post hoc comparisons, when undertaken, included adjustment for multiple testing. Pearson’s correlation was used for approximately linear relationships between suitable continuous variables. Spearman’s rank correlation was used for ordinal variables, including radiographic grade, or when the assumptions for Pearson’s correlation were unsuitable. Associations between categorical variables were assessed using the chi-square test or Fisher’s exact test when expected cell frequencies were small. Multivariable linear regression was used to examine factors independently associated with the WOMAC physical function score. A limited, clinically prespecified set of variables was considered, including age, sex, BMI, symptom duration, occupational knee-loading exposure, previous injury, bilateral involvement and radiographic severity. Pain intensity was examined in an additional model because adjustment for pain could alter the interpretation of associations between structural disease and disability. Regression assumptions were assessed through residual diagnostics, and multicollinearity was evaluated using variance inflation factors. Adjusted regression coefficients, 95% confidence intervals and p values were reported. Robust standard errors were used when heteroscedasticity was identified. Missing observations and the number of participants included in each analysis were documented. All tests were two-sided, and p < 0.05 was considered statistically significant. Findings were interpreted as cross-sectional associations rather than causal effects. Data Collection Data were collected using a standardised case record form containing demographic information, exposure history, anthropometric measurements, clinical findings, radiographic grades, pain ratings and WOMAC scores. Trained study personnel followed uniform instructions for interviews and measurements. Questionnaire assistance was provided without suggesting responses. Forms were reviewed after each assessment to resolve omissions where possible. Electronic entries were checked against source records, and range and consistency checks were performed before analysis. Access to identifiable information was restricted to authorised study personnel.

Table 1. Selected risk-factor profiles and their unadjusted associations with functional disability among patients with knee osteoarthritis (N=200) Characteristic: comparison First group, n (%) Second group, n (%) First group WOMAC function, Mean (SD) Second group WOMAC function, Mean (SD) Mean difference (95% CI) Welch’s t p value Age: ≥60 versus <60 years 104 (52.0) 96 (48.0) 26.03 (7.91) 25.44 (8.09) 0.59 (-1.64 to 2.82) 0.522 0.602 Sex: female versus male 123 (61.5) 77 (38.5) 26.73 (7.38) 24.17 (8.67) 2.56 (0.21 to 4.92) 2.151 0.033 BMI: ≥30 versus <30 kg/m² 40 (20.0) 160 (80.0) 28.68 (8.45) 25.01 (7.71) 3.66 (0.72 to 6.60) 2.494 0.016 Occupational knee-loading exposure: present versus absent 113 (56.5) 87 (43.5) 26.03 (8.16) 25.38 (7.77) 0.65 (-1.59 to 2.88) 0.571 0.568 Previous knee injury: present versus absent 37 (18.5) 163 (81.5) 25.78 (6.41) 25.74 (8.31) 0.05 (-2.42 to 2.52) 0.038 0.969 Knee involvement: bilateral versus unilateral 129 (64.5) 71 (35.5) 26.84 (7.70) 23.75 (8.14) 3.10 (0.76 to 5.43) 2.625 0.010 Among 200 patients, women had significantly higher mean WOMAC physical function scores than men (26.73 ± 7.38 versus 24.17 ± 8.67), indicating greater functional disability, with a mean difference of 2.56 points (95% CI: 0.21-4.92; t=2.151; p=0.033). Patients with BMI ≥30 kg/m² also had higher scores than those with BMI <30 kg/m² (28.68 ± 8.45 versus 25.01 ± 7.71), with a mean difference of 3.66 points (95% CI: 0.72-6.60; t=2.494; p=0.016). Similarly, bilateral involvement was associated with greater disability than unilateral involvement (26.84 ± 7.70 versus 23.75 ± 8.14), with a mean difference of 3.10 points (95% CI: 0.76-5.43; t=2.625; p=0.010). Differences according to age group (p=0.602), occupational knee-loading exposure (p=0.568) and previous knee injury (p=0.969) were not statistically significant in the unadjusted analyses. Table 2. Demographic, anthropometric, occupational and clinical characteristics of patients with knee osteoarthritis (N=200) Characteristic n (%) or Mean (SD) 95% CI for percentage or mean Demographic characteristics Age, years 59.73 (9.08) 58.46-60.99 Age <60 years 96 (48.0) 41.2-54.9 Age ≥60 years 104 (52.0) 45.1-58.8 Male 77 (38.5) 32.0-45.4 Female 123 (61.5) 54.6-68.0 Anthropometric characteristics BMI, kg/m² 26.95 (3.57) 26.45-27.45 BMI <30 kg/m² 160 (80.0) 73.9-85.0 BMI ≥30 kg/m² 40 (20.0) 15.0-26.1 Occupational characteristics Occupational knee-loading exposure present 113 (56.5) 49.6-63.2 Occupational knee-loading exposure absent 87 (43.5) 36.8-50.4 Clinical characteristics Duration of symptoms, years 4.72 (3.34) 4.26-5.19 Previous knee injury 37 (18.5) 13.7-24.5 Unilateral involvement 71 (35.5) 29.2-42.3 Bilateral involvement 129 (64.5) 57.7-70.8 Pain intensity, numerical rating scale (0-10) 4.97 (1.37) 4.78-5.16 Radiological severity Kellgren-Lawrence grade 2 73 (36.5) 30.1-43.4 Kellgren-Lawrence grade 3 86 (43.0) 36.3-49.9 Kellgren-Lawrence grade 4 41 (20.5) 15.5-26.6 The mean age of the patients was 59.73 ± 9.08 years (95% CI: 58.46-60.99), and 104 (52.0%) were aged ≥60 years. Women constituted 123 (61.5%) participants, while 77 (38.5%) were men. The mean BMI was 26.95 ± 3.57 kg/m² (95% CI: 26.45-27.45), with 40 patients (20.0%) having BMI ≥30 kg/m². Occupational knee-loading exposure was reported by 113 patients (56.5%), and previous knee injury by 37 (18.5%). The mean symptom duration was 4.72 ± 3.34 years, while the mean pain intensity score was 4.97 ± 1.37. Bilateral knee involvement was present in 129 patients (64.5%), compared with unilateral involvement in 71 (35.5%). Kellgren-Lawrence grade 3 was the most frequent radiological category, observed in 86 patients (43.0%), followed by grade 2 in 73 (36.5%) and grade 4 in 41 (20.5%). Table 3. WOMAC physical function scores overall and according to radiological severity (N=200) Assessment/group n (%) WOMAC physical function, Mean (SD) 95% CI for mean Test statistic p value Overall physical function score, 0-68 200 (100.0) 25.74 (7.98) 24.63-26.86 Normalised physical function score, 0-100 200 (100.0) 37.86 (11.74) 36.22-39.50 Physical function score (0-68) by radiological grade Kellgren-Lawrence grade 2 73 (36.5) 22.81 (7.69) 21.01-24.60 Kellgren-Lawrence grade 3 86 (43.0) 26.00 (7.74) 24.34-27.66 Kellgren-Lawrence grade 4 41 (20.5) 30.44 (6.67) 28.33-32.55 Overall comparison across grades 2-4 200 (100.0) F(2,197)=13.612 <0.001 The overall mean WOMAC physical function score was 25.74 ± 7.98 on the 0-68 scale (95% CI: 24.63-26.86), corresponding to a normalised score of 37.86 ± 11.74 on the 0-100 scale (95% CI: 36.22-39.50). Mean disability scores increased across radiological severity categories, from 22.81 ± 7.69 in patients with Kellgren-Lawrence grade 2 to 26.00 ± 7.74 in grade 3 and 30.44 ± 6.67 in grade 4. The overall difference between the three groups was statistically significant (F[2,197]=13.612; p<0.001). These findings indicated greater average functional disability with higher radiological grades; however, the overall ANOVA did not establish the significance of individual pairwise differences. Table 4. Multivariable associations of demographic and clinical factors, pain intensity and radiological severity with WOMAC physical function scores (N=200) Independent variable Distribution, n (%) or Mean (SD) Adjusted coefficient, B 95% CI for B Robust t statistic p value Age, per additional year 59.73 (9.08) 0.223 0.122 to 0.324 4.368 <0.001 Female sex, versus male 123 (61.5) 2.848 0.936 to 4.760 2.938 0.004 BMI, per additional kg/m² 26.95 (3.57) 0.626 0.370 to 0.881 4.832 <0.001 Symptom duration, per additional year 4.72 (3.34) 0.352 0.073 to 0.632 2.489 0.014 Occupational knee-loading exposure, present versus absent 113 (56.5) 2.585 0.776 to 4.394 2.819 0.005 Previous knee injury, present versus absent 37 (18.5) 0.857 -1.450 to 3.165 0.733 0.465 Bilateral involvement, versus unilateral 129 (64.5) 2.851 1.029 to 4.673 3.087 0.002 Pain intensity, per additional numerical rating scale point 4.97 (1.37) 1.836 1.141 to 2.532 5.208 <0.001 Kellgren-Lawrence grade 3, versus grade 2 86 (43.0) 3.079 1.040 to 5.118 2.979 0.003 Kellgren-Lawrence grade 4, versus grade 2 41 (20.5) 6.529 4.202 to 8.856 5.534 <0.001 Multivariable analysis showed that increasing age (B=0.223; 95% CI: 0.122-0.324; p<0.001), female sex (B=2.848; 95% CI: 0.936-4.760; p=0.004), higher BMI (B=0.626; 95% CI: 0.370-0.881; p<0.001) and longer symptom duration (B=0.352; 95% CI: 0.073-0.632; p=0.014) were independently associated with higher WOMAC physical function scores. Occupational knee-loading exposure (B=2.585; 95% CI: 0.776-4.394; p=0.005) and bilateral involvement (B=2.851; 95% CI: 1.029-4.673; p=0.002) were also associated with greater disability after adjustment. Each additional pain intensity point was associated with a 1.836-point higher disability score (95% CI: 1.141-2.532; p<0.001). Compared with grade 2, Kellgren-Lawrence grades 3 and 4 were associated with scores higher by 3.079 points (95% CI: 1.040-5.118; p=0.003) and 6.529 points (95% CI: 4.202-8.856; p<0.001), respectively. Previous knee injury was not significantly associated with disability after adjustment (B=0.857; 95% CI: -1.450 to 3.165; p=0.465).

1. Overall findings and relevance The supplied analysis of 200 patients illustrated associations between functional disability and several demographic, anthropometric and clinical characteristics. Female sex, obesity and bilateral knee involvement were associated with higher WOMAC physical function scores in unadjusted comparisons, while the multivariable analysis additionally identified associations with age, symptom duration, occupational knee-loading exposure, pain intensity and radiological severity. Hunter and Bierma-Zeinstra (2019) [1] described osteoarthritis as a whole-joint disorder involving interacting mechanical and biological processes, providing a conceptual basis for evaluating multiple characteristics rather than radiological changes alone. Safiri et al. (2020) [2] documented the substantial global burden of osteoarthritis-related disability, while Cui et al. (2020) [3] reported a pooled knee osteoarthritis prevalence of 22.9% among adults aged ≥40 years. These publications establish the importance of functional assessment, although population prevalence estimates cannot be directly compared with findings from a sample consisting entirely of patients with osteoarthritis. 2. Demographic and anthropometric characteristics In Table 2, the mean age was 59.73 ± 9.08 years, 52.0% of patients were aged ≥60 years, and 61.5% were women. This demographic pattern broadly resembled the age and sex distribution described by Pal et al. (2016) [4], who reported a community prevalence of knee osteoarthritis of 28.7% in India and associations with increasing age, female sex and obesity. However, the proportion of women in the supplied hospital sample represented its composition rather than a sex-specific prevalence estimate. The mean BMI of 26.95 ± 3.57 kg/m² and the presence of BMI ≥30 kg/m² in 20.0% of patients also highlighted the relevance of assessing body weight. Kolasinski et al. (2020) [5] recommended weight reduction for overweight or obese patients with knee osteoarthritis alongside exercise and self-management; these recommendations provide clinical context but do not demonstrate treatment effects in this cross-sectional dataset. Women had higher disability scores than men in Table 1, with a mean difference of 2.56 points (95% CI: 0.21-4.92; p=0.033). Female sex remained associated with higher scores after adjustment (B=2.848; p=0.004). Silverwood et al. (2015) [6] identified female sex, excess body weight and previous knee injury as factors associated with the development of knee osteoarthritis. Their findings support the relevance of these characteristics in osteoarthritis research, but they address disease onset rather than the severity of disability among already affected patients. Thus, the agreement is contextual rather than a direct replication of their findings. 3. Obesity and functional disability Patients with BMI ≥30 kg/m² had higher mean WOMAC function scores than those with BMI <30 kg/m², with a difference of 3.66 points (95% CI: 0.72-6.60; p=0.016). In the adjusted model, each additional BMI unit was associated with a 0.626-point higher disability score (95% CI: 0.370-0.881; p<0.001). Zheng and Chen (2015) [7] reported that each 5 kg/m² increase in BMI was associated with a 35% increase in the risk of knee osteoarthritis. Although their outcome differed from functional disability, their results supported the broader importance of excess body weight in knee osteoarthritis. More directly relevant to function, Hall et al. (2019) [8] found that dietary weight loss, alone or combined with exercise, improved physical function in overweight or obese patients with knee osteoarthritis. These intervention findings support weight management as a potential clinical strategy; however, the supplied BMI coefficient cannot be interpreted as the improvement expected from reducing BMI. 4. Age, symptom duration and bilateral involvement Age showed no statistically significant association with disability when categorised as ≥60 versus <60 years in Table 1 (p=0.602), but continuous age was significant in the adjusted model (B=0.223; 95% CI: 0.122-0.324; p<0.001). These analyses estimated different relationships: dichotomisation reduced the information available, while multivariable adjustment accounted for other measured characteristics. Bastick et al. (2015) [9] found evidence linking age, BMI, comorbidity and baseline disease severity with clinical progression of knee osteoarthritis. Their longitudinal evidence was broadly compatible with the adjusted age association, although a cross-sectional analysis could not establish progression. Longer symptom duration was also associated with greater disability in Table 4 (B=0.352; p=0.014), but this did not demonstrate that disability increased by that amount within individuals over time. Bilateral involvement occurred in 64.5% of patients and was associated with higher disability scores in both unadjusted and adjusted analyses. The adjusted difference was 2.851 points compared with unilateral disease (95% CI: 1.029-4.673; p=0.002). One plausible explanation is that involvement of both knees limits the ability to compensate using a less affected limb during walking, transfers and stair climbing. Nevertheless, this mechanism was not measured in the supplied tables, and bilateral involvement could also reflect differences in overall disease burden. 5. Occupational exposure and previous knee injury Occupational knee-loading exposure was present in 56.5% of patients. Its unadjusted association with disability was not significant (p=0.568), whereas the adjusted association was significant (B=2.585; 95% CI: 0.776-4.394; p=0.005). Wang et al. (2020) [10] reported associations between occupational exposures and knee osteoarthritis in their systematic review and meta-analysis. Their findings support careful assessment of physically demanding work, but primarily concern osteoarthritis occurrence rather than disability among affected patients. The change between the supplied unadjusted and adjusted results could reflect the distribution of other covariates; it does not by itself establish confounding or a causal occupational effect. Interpretation would also require a clear definition of exposure duration and intensity. Previous knee injury was not significantly associated with disability in either analysis, including the adjusted model (B=0.857; 95% CI: -1.450 to 3.165; p=0.465). Poulsen et al. (2019) [11] found substantially increased odds of developing osteoarthritis after anterior cruciate ligament, meniscal or combined injuries. The supplied nonsignificant finding does not contradict this evidence because the outcome here was current disability among patients who already had osteoarthritis. Furthermore, only 37 patients reported previous injury, and the confidence interval remained compatible with both lower and higher disability scores. Injury type, severity and time since injury would be important additional variables. 6. WOMAC functional assessment and radiological severity The overall WOMAC physical function score was 25.74 ± 7.98, equivalent to 37.86 ± 11.74 on a normalised 0-100 scale. White and Master (2016) [12] reviewed the measurement properties of WOMAC and other patient-reported functional instruments, supporting their role in assessing limitations relevant to patients. Direct numerical comparison with other studies requires the same WOMAC version, scoring direction, domain and scale. The supplied normalised score should therefore not be interpreted as a percentage of patients with disability or assigned a severity category without validated thresholds. Mean function scores increased from 22.81 in Kellgren-Lawrence grade 2 to 26.00 in grade 3 and 30.44 in grade 4, with a significant overall difference (F=13.612; p<0.001). Wilson et al. (2018) [13], using Osteoarthritis Initiative data, similarly reported progressively poorer physical dimensions of health with increasing radiographic severity. However, Özden et al. (2020) [14] found that radiographic findings were associated with activity-related pain and performance-based function, but not with patient-reported outcomes. This contrasting evidence demonstrates that structural severity and perceived disability are related imperfectly. Differences in outcome instruments, recruitment and disease severity may contribute to variation between studies. The supplied ANOVA established an overall group difference but did not establish that every pair of grades differed significantly. 7. Pain intensity and adjusted associations Pain intensity was associated with greater functional disability after adjustment, with a 1.836-point increase in WOMAC function score per additional pain-rating point (95% CI: 1.141-2.532; p<0.001). Sandhar et al. (2020) [15], in a systematic review involving 82 studies and 41,810 participants, examined the diverse factors associated with pain and functional impairment in knee and hip osteoarthritis. Their work supports assessing symptoms and function within a broader clinical framework. In the supplied analysis, pain and disability were measured concurrently, so the coefficient could not establish temporal direction. Additionally, adjustment for pain may remove part of the pathway through which structural disease affects function; consequently, the adjusted radiological coefficients should not be interpreted as total causal effects. 8. Clinical implications and interpretation The illustrative pattern suggests the value of assessing body weight, pain, occupational demands, bilateral involvement and radiological severity alongside functional limitations. Fransen et al. (2015) [16] found that land-based therapeutic exercise improved pain and physical function in knee osteoarthritis, supporting rehabilitation as an important component of care. Together with the recommendations of Kolasinski et al. (2020) [5], this evidence supports individualised exercise, appropriate weight management and symptom assessment. Nevertheless, the supplied tables cannot demonstrate treatment effectiveness, causal relationships or predictors of future deterioration. Their unadjusted comparisons were exploratory, and statistically significant differences should not automatically be considered clinically important without an appropriate interpretive threshold.

Functional disability among patients with knee osteoarthritis was associated with multiple demographic and clinical characteristics. Increasing age, female sex, higher BMI, longer symptom duration, occupational knee-loading exposure, bilateral involvement, greater pain intensity and higher radiological grades were independently associated with higher WOMAC physical function scores. Previous knee injury showed no statistically significant adjusted association. These findings highlighted the importance of assessing functional limitations alongside pain, anthropometric characteristics and radiological severity. However, the cross-sectional associations did not establish causation or demonstrate that modifying these factors would improve disability. LIMITATIONS OF THE STUDY The cross-sectional design prevented determination of temporal relationships and causal effects between the assessed factors and functional disability. The proposed single-centre, hospital-based recruitment using consecutive sampling could introduce selection bias and limit generalisability to community populations. Since all participants had knee osteoarthritis, the analysis could not identify risk factors for developing the disease. Occupational exposure, previous injury and symptom duration relied on participant recall and were susceptible to misclassification. WOMAC measured self-reported limitations, which could be influenced by pain perception and psychological factors; objective performance-based assessments were not included in the reported tables. Potential confounders, including muscle strength, depression, comorbidity burden, physical activity and treatment use, were not incorporated into the regression model. Furthermore, the sample-size calculation addressed descriptive precision rather than power for individual associations, and unadjusted comparisons were exploratory without correction for multiple testing. Statistical significance did not necessarily indicate clinically important differences, and the absence of follow-up prevented evaluation of functional progression.

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