Osteoarthritis is a chronic whole-joint disorder characterized by progressive structural alteration of articular cartilage, subchondral bone, synovium, ligaments, capsule, and periarticular muscles. Knee osteoarthritis is particularly important because the knee is a major weight-bearing joint and even moderate structural disease can produce pain, stiffness, impaired gait, difficulty in stair climbing, and loss of independence. Global burden studies have consistently identified hip and knee osteoarthritis as major contributors to disability, with higher burden among older adults and women [1]. Contemporary reviews also emphasize that osteoarthritis is not merely a cartilage disease, but a complex interaction of mechanical loading, metabolic factors, inflammation, pain processing, and functional adaptation [2].

The clinical expression of knee osteoarthritis varies widely. Some patients with radiological changes have minimal symptoms, while others experience severe pain and activity restriction. Ageing, female sex, increased body mass index, previous knee injury, occupational loading, quadriceps weakness, and sedentary behaviour have been reported as important correlates of knee osteoarthritis and its progression [3,4]. Pain remains the dominant symptom and is often the main reason for health-care consultation. Persistent knee pain alters mobility, reduces physical activity, promotes muscle weakness, and increases the risk of disability, particularly in patients with bilateral involvement [4].

In the Indian setting, knee osteoarthritis has considerable public health relevance because of population ageing, high prevalence of overweight and obesity, squatting and floor-sitting practices, and delayed presentation to orthopaedic services. Indian population-based studies using clinical and radiological assessment have reported substantial knee osteoarthritis prevalence and have identified age, female sex, obesity, and sedentary lifestyle as important associated factors [9,10]. These findings support the need for hospital-based studies that document not only disease presence but also the functional burden among patients seeking care.

Functional disability is commonly assessed using patient-reported outcome measures. The Western Ontario and McMaster Universities Osteoarthritis Index is a validated instrument for assessing pain, stiffness, and physical function in patients with hip or knee osteoarthritis [6]. 

Study design and setting: This hospital-based observational cross-sectional study was conducted in the Department of Orthopaedics, Konaseema Institute of Medical Sciences & Research Foundation, Amalapuram, Andhra Pradesh, India. The study was carried out over a six-month period from May 2021 to October 2021. The hospital caters to patients from Amalapuram and nearby rural and semi-urban areas, providing outpatient, inpatient, radiology, physiotherapy, and operative orthopaedic services. Study population: The study population consisted of adult patients attending the orthopaedic outpatient department with clinical features suggestive of knee osteoarthritis. Patients were evaluated by history, physical examination, and radiological assessment. Knee osteoarthritis was diagnosed using clinical and radiological criteria consistent with accepted classification approaches for idiopathic knee osteoarthritis [5]. Sample size and sampling method: A total of 100 eligible patients were included during the study period. Consecutive sampling was used, wherein all patients fulfilling the eligibility criteria and providing consent were enrolled until the required sample size was completed. The sample size was considered adequate for estimating the demographic and clinical pattern of knee osteoarthritis in a descriptive hospital-based study. Inclusion and exclusion criteria: Patients aged 40 years and above with knee pain, clinical features of osteoarthritis, and radiological evidence of knee osteoarthritis were included. Patients with inflammatory arthritis, rheumatoid arthritis, gout, septic arthritis, acute traumatic knee injury, previous knee arthroplasty, congenital deformity, neurological disease affecting gait, or incomplete clinical records were excluded to avoid confounding of functional disability assessment. Data collection procedure: Demographic information including age, sex, residence, occupation, and body mass index was recorded using a predesigned data collection form. Clinical details included duration of symptoms, side of knee involvement, pain severity, morning stiffness, crepitus, difficulty in squatting, difficulty in stair climbing, and use of walking support. Pain intensity was assessed using the visual analogue scale. Radiological and functional assessment: Standard knee radiographs were reviewed and graded using the Kellgren-Lawrence grading system, which classifies osteoarthritis severity based on osteophytes, joint-space narrowing, sclerosis, and bony deformity [7,8]. Functional disability was assessed using the WOMAC index, a validated patient-reported instrument covering pain, stiffness, and physical function domains [6]. Higher WOMAC scores indicated greater disability. Total WOMAC scores were categorized into mild, moderate, and severe functional disability for analysis. Statistical analysis: Data were entered into a spreadsheet and analyzed using descriptive statistics. Continuous variables were expressed as mean ± standard deviation. Categorical variables were presented as frequency and percentage. Associations between selected clinical variables and severe functional disability were tested using the Chi-square test. A p-value less than 0.05 was considered statistically significant. Ethical considerations: Written informed consent was obtained from all participants before enrolment. Confidentiality of patient information was maintained throughout the study, and anonymized data were used for analysis. The study was conducted in accordance with ethical principles for biomedical research involving human participants.

Table 1. Baseline demographic profile of the study population [n=100]

The clinical profile and radiological severity are presented in Table 2. Symptom duration of 1-3 years was observed in 44.0% of patients, while 34.0% had symptoms for more than 3 years. Bilateral knee involvement was the most common pattern, seen in 56.0%. Moderate pain was reported by 52.0%, and severe pain by 30.0%. The mean visual analogue scale score was 6.4 ± 1.7. Difficulty in stair climbing was the most frequent functional complaint, followed by difficulty in squatting and crepitus. Radiological assessment showed that Kellgren-Lawrence Grade III was the most common grade, observed in 38.0% of patients, followed by Grade II in 34.0%.

Table 3. WOMAC functional disability assessment among patients with knee osteoarthritis [n=100]

The association between selected variables and severe functional disability is shown in Table 4. Severe functional disability was significantly associated with age ≥60 years, female sex, overweight or obesity, symptom duration of more than 3 years, bilateral knee involvement, and Kellgren-Lawrence Grade III/IV disease. Overweight or obesity showed the strongest association among the analyzed variables. Patients with bilateral disease and advanced radiological grade had a higher proportion of severe disability compared with their respective comparison groups.

Functional disability assessed using WOMAC is summarized in Table 3. The mean WOMAC pain score was 11.8 ± 3.6, the stiffness score was 4.9 ± 1.8, and the physical function score was 38.6 ± 10.4. The mean total WOMAC score was 55.3 ± 13.8, indicating a moderate functional disability burden in the overall study population. Moderate disability was observed in 48.0% of patients, severe disability in 34.0%, and mild disability in 18.0%.

Table 2. Clinical profile and radiological severity of knee osteoarthritis [n=100]

Table 4. Association between selected variables and severe functional disability [n=100]

Values in Table 4 indicate the number of patients with the specified characteristic in each disability group. The Chi-square test compared presence versus absence of each variable across disability categories.

The present observational study evaluated the clinical profile and functional disability among 100 patients with knee osteoarthritis attending a tertiary care hospital. The mean age of 58.6 years indicates that most patients were in the late middle-aged and elderly age groups, which is consistent with the age-related increase in knee osteoarthritis described in epidemiological studies [3]. Female predominance was also observed. This finding agrees with global and Indian data showing higher symptomatic and radiographic knee osteoarthritis burden among women, particularly after middle age [1,9,10]. Hormonal changes, differences in body composition, occupational exposure, and health-seeking patterns are possible contributors to this distribution.

Excess body weight was frequent in this cohort, with 82.0% of patients being overweight or obese. Obesity increases mechanical load across the tibiofemoral joint and also contributes through metabolic and inflammatory pathways [2,11]. In the present study, overweight or obesity was significantly associated with severe functional disability. This supports the clinical relevance of weight assessment in every patient with knee osteoarthritis. Weight reduction counselling, low-impact exercise, strengthening of periarticular muscles, and patient education need to be integrated early rather than reserved for advanced disease.

Bilateral knee involvement was present in more than half of the patients. Bilateral disease is clinically important because it reduces compensatory capacity during walking, squatting, stair climbing, and rising from sitting. Difficulty in stair climbing was the most common functional complaint in the present study, followed by difficulty in squatting. These activities are particularly relevant in the Indian context, where household, occupational, and cultural practices often require repeated knee flexion. The mean WOMAC score reflected moderate disability overall, while one-third of patients had severe disability. Similar studies have shown that WOMAC physical function is strongly related to perceived disability and disease burden in knee osteoarthritis [12,14].

Radiological grading showed that Grade III disease was the most common finding, and advanced radiological grade was significantly associated with severe functional disability. This direction of association is expected, although previous studies have shown that the relationship between radiographic severity and pain or disability is not always linear [12,13]. Pain processing, muscle strength, psychosocial factors, body weight, occupational demands, and duration of disease influence the final functional status. Therefore, radiographs alone should not determine clinical decisions. A combined assessment that includes pain severity, WOMAC domains, bilateral involvement, and mobility limitation provides a more useful representation of patient burden.

The findings highlight the need for early recognition and structured assessment of knee osteoarthritis in outpatient practice. Patients with older age, female sex, excess body weight, longer symptom duration, bilateral disease, and Grade III/IV radiological changes deserve closer functional evaluation. WOMAC scoring offers a practical method for documenting baseline disability, monitoring progression, and assessing response to conservative treatment, physiotherapy, lifestyle intervention, and surgical referral when appropriate [6].

Limitations

This study was conducted at a single tertiary care hospital with a sample size of 100 patients; therefore, the findings are not fully generalizable to the wider community. The cross-sectional design limits temporal interpretation between risk factors and disability. Functional disability was assessed using self-reported WOMAC responses, which can be influenced by pain perception, literacy, occupation, and daily activity pattern.

Knee osteoarthritis in this tertiary care cohort was commonly observed among older adults, females, and patients with excess body weight. Bilateral knee involvement, moderate-to-severe pain, stair-climbing difficulty, squatting difficulty, and advanced Kellgren-Lawrence grades were frequent clinical features. WOMAC assessment demonstrated a considerable functional burden, with nearly one-third of patients having severe disability. Severe disability was significantly associated with age ≥60 years, female sex, overweight or obesity, longer symptom duration, bilateral disease, and Grade III/IV radiological severity. Routine functional assessment, weight management, pain control, physiotherapy, and timely follow-up should be emphasized to reduce disability and improve quality of life in patients with knee osteoarthritis.

1. Cross M, Smith E, Hoy D, Nolte S, Ackerman I, Fransen M, et al. The global burden of hip and knee osteoarthritis: estimates from the global burden of disease 2010 study. Ann Rheum Dis. 2014;73(7):1323-30. doi:10.1136/annrheumdis-2013-204763. PMID:24553908.
2. Hunter DJ, Bierma-Zeinstra S. Osteoarthritis. Lancet. 2019;393(10182):1745-59. doi:10.1016/S0140-6736(19)30417-9. PMID:31034380.
3. Zhang Y, Jordan JM. Epidemiology of osteoarthritis. Clin Geriatr Med. 2010;26(3):355-69. doi:10.1016/j.cger.2010.03.001. PMID:20699159.
4. Neogi T. The epidemiology and impact of pain in osteoarthritis. Osteoarthritis Cartilage. 2013;21(9):1145-53. doi:10.1016/j.joca.2013.03.018. PMID:23973124.
5. Altman R, Asch E, Bloch D, Bole G, Borenstein D, Brandt K, et al. Development of criteria for the classification and reporting of osteoarthritis: classification of osteoarthritis of the knee. Arthritis Rheum. 1986;29(8):1039-49. doi:10.1002/art.1780290816. PMID:3741515.
6. Bellamy N, Buchanan WW, Goldsmith CH, Campbell J, Stitt LW. Validation study of WOMAC: a health status instrument for measuring clinically important patient-relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. J Rheumatol. 1988;15(12):1833-40. PMID:3068365.
7. Kellgren JH, Lawrence JS. Radiological assessment of osteo-arthrosis. Ann Rheum Dis. 1957;16(4):494-502. doi:10.1136/ard.16.4.494. PMID:13498604.
8. Kohn MD, Sassoon AA, Fernando ND. Classifications in brief: Kellgren-Lawrence classification of osteoarthritis. Clin Orthop Relat Res. 2016;474(8):1886-93. doi:10.1007/s11999-016-4732-4. PMID:26872913.
9. Pal CP, Singh P, Chaturvedi S, Pruthi KK, Vij A. Epidemiology of knee osteoarthritis in India and related factors. Indian J Orthop. 2016;50(5):518-22. doi:10.4103/0019-5413.189608. PMID:27746495.
10. Kumar H, Pal CP, Sharma YK, Kumar S, Uppal A. Epidemiology of knee osteoarthritis using Kellgren and Lawrence scale in Indian population. J Clin Orthop Trauma. 2020;11(Suppl 1):S125-9. PMID:31992932.
11. Coggon D, Reading I, Croft P, McLaren M, Barrett D, Cooper C. Knee osteoarthritis and obesity. Int J Obes Relat Metab Disord. 2001;25(5):622-7. doi:10.1038/sj.ijo.0801585. PMID:11360143.
12. Cubukcu D, Sarsan A, Alkan H. Relationships between pain, function and radiographic findings in osteoarthritis of the knee: a cross-sectional study. Arthritis. 2012;2012:984060. doi:10.1155/2012/984060. PMID:23209900.
13. Sanghi D, Avasthi S, Mishra A, Singh A, Agarwal S, Srivastava RN. Is radiology a determinant of pain, stiffness, and functional disability in knee osteoarthritis? A cross-sectional study. J Orthop Sci. 2011;16(6):719-25. doi:10.1007/s00776-011-0147-y. PMID:21874334.
14. Georgiev T, Angelov AK, Stoilov R, Ivanova M, Manolova I, Kabakchieva P, et al. Clinical characteristics and disability in patients with knee osteoarthritis: real world experience from Bulgaria. Reumatologia. 2019;57(2):78-84. doi:10.5114/reum.2019.84813. PMID:31130745.