Knee osteoarthritis is a primary driver of chronic musculoskeletal pain and global disability. When conservative treatments run their course, total knee arthroplasty (TKA) stands as the definitive surgical intervention [1, 2]. Historically, orthopaedic surgeons have relied on implant survivorship, radiographic alignment, and joint mechanics as the ultimate indicators of a successful procedure. However, a notable 10–25% of patients with technically flawless knee replacements still report chronic dissatisfaction. This discrepancy highlights a critical blind spot: the gap between structural success and the patient’s actual lived experience [3–5].

Patient-reported outcome measures (PROMs) were designed to bridge this divide. Standardized questionnaires like the Visual Analogue Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Knee Score (OKS), and the Short Form-36 (SF-36) empower patients to independently grade their pain, joint function, and quality of life [6–9]. Today, large-scale national joint registries across the UK, Australia, and Europe mandate PROM collection, fundamentally shifting how the medical community defines arthroplasty success [10, 11].

Despite this global shift, localized data from India—particularly Eastern India—is surprisingly limited. Most regional studies still focus heavily on implant longevity or physician-graded scores. This overlooks vital cultural nuances, such as the need for floor-sitting, squatting, and barefoot walking, which heavily influence a patient's perception of recovery but are often missed by Western assessment tools [12, 13]. To address this evidence gap, our study prospectively charts PROM trajectories, measures clinical relevance through minimal clinically important difference (MCID) thresholds, and identifies demographic variables influencing recovery among primary TKA patients at a government tertiary-care center in Eastern India.

Study Design and Setting We conducted a prospective longitudinal observational cohort study at the Department of Orthopaedics, SCB Medical College and Hospital in Cuttack, Odisha. The study spanned two years (February 2024–January 2026). Prior to enrollment, we secured approval from the Institutional Ethics Committee, and every participant provided written informed consent. Participants We consecutively enrolled 73 eligible patients undergoing primary unilateral TKA for primary knee osteoarthritis. Inclusion criteria required patients to be under 80 years old, present with radiographic Kellgren–Lawrence grade III or IV disease, be capable of completing PROM questionnaires, and commit to a minimum six-month follow-up. We excluded individuals undergoing revision surgery, those with secondary osteoarthritis (inflammatory or post-traumatic), previous index knee surgeries, or systemic/neurological conditions impeding gait. Clinical and Surgical Protocol Baseline demographic data—including age, biological sex, symptom duration, body mass index (BMI), comorbidities, and deformity patterns—were recorded systematically. Pre-operative workups included weight-bearing radiographs and lower-limb scanograms. All surgeries utilized a medial parapatellar approach to implant a cemented posterior-stabilized prosthesis. Post-operatively, all patients adhered to a uniform institutional rehabilitation program. Outcome Measures and Statistical Analysis Patients self-administered the VAS, WOMAC, OKS, and SF-36 questionnaires pre-operatively, and at 1, 3, 6, and 12 months post-surgery. Assistance was provided when necessary. Data analysis was performed using SPSS. Given that longitudinal PROM data lacked normal distribution, we utilized the Friedman test to evaluate overall trends across follow-up intervals, followed by Wilcoxon signed-rank tests for pairwise comparisons against baseline scores. We applied Mann–Whitney U tests and Spearman/Pearson correlations for subgroup and inter-instrument analyses. Binary logistic regression identified independent predictors of a poor 12-month outcome. Statistical significance was set at p < 0.05. We determined clinically meaningful improvements based on established MCID thresholds (VAS ≥ 2 points; WOMAC ≥ 12 points; OKS ≥ 5 points; SF-36 ≥ 10 points).

Baseline Characteristics

The cohort’s average age was 62.8 ± 4.3 years, with a strong female majority (67.1%). The mean BMI was 27.7 kg/m², categorizing 76.7% of the cohort as overweight or obese. Patients endured knee symptoms for an average of 6.5 years prior to surgery. Varus deformities were significantly more common than valgus deformities (Table 1).

Table 1. Baseline Demographic and Clinical Characteristics (n = 73)

Surgical Outcomes and Complications

Surgeries averaged 96.7 minutes with a tourniquet time of 66.3 minutes. Over 90% of patients experienced no immediate post-operative complications. Minor issues included superficial infections (4.1%), delayed wound healing (2.7%), and stiffness (2.7%), all of which resolved with conservative management. Notably, the occurrence of early complications did not significantly hinder long-term PROM recovery (Table 2).

Table 2. Correlation Between Immediate Post-Operative Complications and 12-Month PROM Change

Trajectory of PROM Scores

Patient recovery followed a distinct curve: rapid, transformative improvement within the first 90 days, transitioning into gradual, sustained refinement up to the 12-month mark. All metrics showed statistically significant overall improvement (Table 3). By the end of the year, VAS scores plummeted by 86.5%, and condition-specific functional scores (WOMAC and OKS) improved by 65.5% and 79.3%, respectively.

Table 3. Mean PROM Scores and Changes Over 12 Months

*Derived via Friedman test confirming significant change across all post-operative intervals compared to baseline.

Clinical Significance: MCID Achievement

Statistical gains translated directly into tangible, real-world relief. An overwhelming majority of the cohort achieved the Minimal Clinically Important Difference across all tools. Every single patient reported clinically meaningful pain reduction on the VAS (Table 4).

Table 4. Achievement of the Minimal Clinically Important Difference (MCID) at 12 Months

Predictors of Outcome and Instrument Relationships

Binary logistic regression explored potential risk factors for fair-to-poor 12-month outcomes (experienced by 17.8% of the cohort). Advanced age, prolonged preoperative symptoms, and early complications trended toward negative impacts but failed to reach independent statistical significance. BMI had virtually no effect on the outcome (Table 5). Similarly, pre-operative Kellgren-Lawrence radiological severity showed no significant correlation with the degree of PROM improvement.

Table 5. Binary Logistic Regression for Predictors of Poor 12-Month Outcome

At the 12-month mark, the instruments showed robust internal consistency. Reductions in pain (VAS) tracked closely with functional improvements in WOMAC (r = 0.855, p < 0.001). Additionally, the joint-specific Oxford Knee Score strongly correlated with the broader quality-of-life metric SF-36 (r = 0.910, p < 0.001).

This prospective study offers much-needed, region-specific evidence for Eastern India, confirming that TKA delivers profound, quantifiable relief that extends far beyond a well-aligned post-operative X-ray. Measured across four validated scoring systems, patient gains were both statistically robust and clinically transformative, reflecting the success rates observed in massive Western and Australasian joint registries [3, 10, 11]. Our cohort’s demographic profile—predominantly female, in their early sixties, with a high incidence of elevated BMI—aligns neatly with broader Indian and global TKA populations [12, 14, 15]. Interestingly, the average pre-operative symptom duration of 6.5 years is noticeably longer than the 3-to-5-year delays typical of Western cohorts. This likely points to systemic delays in surgical presentation and a heavier reliance on conservative management within resource-constrained government healthcare settings [13]. The recovery timeline observed—a steep upward trajectory of improvement in the first 90 days followed by gradual consolidation up to a year—reassures patients that healing is an ongoing process. It is particularly encouraging that neither elevated BMI nor severe pre-operative angular deformities barred patients from achieving a clinically meaningful recovery. This supports the clinical consensus that well-selected patients benefit equitably from TKA regardless of body habitus or baseline mechanical alignment. Furthermore, the lack of correlation between baseline Kellgren-Lawrence grade and ultimate PROM improvement is a stark reminder: treating the X-ray instead of the patient is a flawed strategy. Radiographic severity is simply not a reliable proxy for the subjective relief a patient will experience post-surgery. While older age, longer symptom duration, and early complications hinted at slightly poorer outcomes, they did not reach statistical significance in our regression model. This is likely an artifact of our modest sample size rather than a true absence of correlation, as larger national databases have flagged these as modest but consistent risk factors. Limitations The primary limitations of this study include its single-center framework, a moderate sample size, and the lack of a control or comparator group (such as alternative implant designs or non-operative management). Furthermore, our follow-up capped at 12 months, leaving the long-term durability of these patient-reported gains unmeasured. Crucially, while we used globally validated PROMs, these Western-centric tools lack modules dedicated to culturally vital Indian activities like floor-sitting and squatting, highlighting an urgent need for localized PROM development.

For patients in Eastern India, total knee arthroplasty yields dramatic, clinically significant enhancements in pain reduction, joint function, and overall quality of life. The vast majority of patients achieve meaningful recovery thresholds by 12 months, irrespective of their baseline BMI, deformity pattern, or radiological severity. Our data advocate strongly for moving beyond the X-ray. Routine integration of PROMs alongside standard surgeon assessments is essential to accurately gauge surgical success. Moving forward, larger multi-center studies utilizing culturally tailored outcome metrics will be vital for refining patient-centered arthroplasty care across India.

Declarations

Ethical Approval: Approved by the Institutional Ethics Committee, SCB Medical College and Hospital, Cuttack, prior to study commencement. Written informed consent was obtained from all participants.

Funding: No funding was received for this study.

Conflict of Interest: The authors declare no conflict of interest.

Data Availability: Data are available from the corresponding author on reasonable request.