Oxford Knee / Hip Score

Each Oxford score presents patients with 12 questions covering pain severity and functional activities relevant to the affected joint—such as walking distance, ability to perform personal hygiene tasks, and difficulty with transportation. Each item is rated on a five-point scale scored 0–4 (best to worst outcome per item under the current recommended system), yielding a total range of 0–48. A score of 0–19 indicates severe arthritis or post-operative problems, 20–29 moderate-to-severe, 30–39 mild-to-moderate, and 40–48 satisfactory joint function. The original 1996 publication by Dawson et al. used a 1–5 reverse scoring convention (total 12–60, higher = worse); Oxford University Innovation later standardized the 0–4 per-item convention to eliminate confusion arising from clinicians who had been inverting or adapting the legacy scale.

Both instruments were developed and are copyright-managed by Oxford University Innovation Limited. Any clinical or commercial deployment—including electronic or digital administration—requires a licence. Publicly funded healthcare organizations and non-commercially funded academic users may obtain that licence free of fee. CMS has incorporated the OHS and OKS into its quality reporting framework for total joint arthroplasty, and participating providers must administer them in a manner consistent with the validated paper-and-pen version to preserve measurement equivalence.

A key psychometric caveat: co-morbidities affecting adjacent joints (e.g., lumbar spine pathology influencing knee or hip perception) can inflate scores and reduce joint specificity. Minimally important change (MIC) thresholds—typically cited around 5 points for both instruments—vary meaningfully by baseline score category, a finding confirmed in large NHS datasets exceeding 387,000 records. Clinicians and coders should therefore treat MIC benchmarks as baseline-dependent estimates rather than fixed cut-points when assessing whether a patient has achieved a clinically meaningful response.

CMS quality programs tie reimbursement and public performance reporting to PROM collection for elective total hip and knee arthroplasty (e.g., the Elective Outpatient Procedure measure set). Failure to collect, score, or submit OHS/OKS data in the required format can result in measure non-compliance, downward payment adjustments, or exclusion from value-based care programs. On the clinical side, an incorrect scoring convention—such as applying the legacy 12–60 scale when a registry or EHR expects 0–48—produces systematically reversed or out-of-range data that renders the outcome meaningless for audit, revision-risk stratification, or shared decision-making. Documentation that captures a specific pre-operative and post-operative score, rather than a narrative impression, is what permits the delta calculation on which MIC determinations depend.