Oxford Arthroplasty Early Recovery Score (OARS)

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The Oxford Arthroplasty Early Recovery Score (OARS) is a 14-item Patient Reported Outcome measure for use in assessing recovery pathways and interventions in arthroplasty.

The Oxford Arthroplasty Early Recovery Score (OARS) is a 14-item Patient Reported Outcome measure developed by researchers at the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences and Nuffield Department of Population Health at the University of Oxford. It was designed and developed in accordance with FDA guidelines (2009) and sector best practices. It is validated for use in the first six weeks following Unicompartmental knee arthroplasty (UKA), Total knee arthroplasty (TKA) and Total hip arthroplasty (THA).

The good measurement properties of the OARS, its relevance to patients, clinicians, and other stakeholders, make it the ideal measurement tool for use in randomised controlled trials that assess the efficiency of different interventions in this patient population.


As surgeons, once our patients are discharged from our care following surgery, they enter a black hole where we lose sight of how they are progressing with their new hip or knee. The OARs and OACs are the assessment tools by which we can now monitor those patients that were previously invisible to us in the days and weeks immediately following hip or knee replacement surgery.

– Professor Oliver Pearce, FRCS, Consultant Trauma and Orthopaedics


Lower limb arthroplasty is a commonly performed procedure for symptomatic end-stage arthritis which has not responded to conservative medical treatment. Each patient’s perspective of the surgical process and early recovery period impacts on their quality of life. The OARS is a brief, easy-to-use measurement tool for use in assessing recovery pathways and interventions in arthroplasty. It taps into patients feeling around four domain: Pain, Sleep, Nausea and feeling unwell, Mobility. It was devised to gain deeper understanding of the patient perspective on their treatment in the perioperative period and can be used to assess change during the first six weeks following surgery.

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Design and development

A five-phased, best practice, iterative approach was used in strict accordance with the Food and Drug Administration (FDA) guidelines: Literature review was followed by Analysis of patient interviews (Phase one), candidate items from Phase One interviews were generated and pilot questionnaire developed and tested in Phase two. Factor analysis with item reduction and final testing of the questionnaire was performed in phase three. Phase Four involved validation testing. The measure was administered to consecutive patients in an independent cohort in combination with a generic heath measure (SF36 v2 Acute).

Prior to testing, a translatability assessment (TA) was performed on the new measure. TA has been recognised as an important part of the questionnaire development process. It provides insight into what extent the items in the questionnaires can be translated into other languages and cultures. This is of particular importance for use in cross cultural trials.

In addition, a concept elaboration document (CED) was created to fully define and clarify question items and the meanings attributed to them. This was developed in combination with the developers and specialist translators, to provide specific detail regarding the explicit line-by-line meaning of items and concepts, providing clarification of each item of the questionnaire.

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Scoring system

A scoring guide is available specifically for the OARS and details how to score the change measure across a range of 100, with 0 being poor recovery, to 100 being positive and indicative of a good recovery. The guide also addresses scoring the separate domains (Pain and Nausea and feeling unwell; Fatigue and Sleep and Increasing function and mobility. It also recommends how to treat missing responses.

The scoring system for the sister measure OACS is different and should only be applied to OACS questionnaire.

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Complementary Measures

The OARS can be used with an early change assessment tool, the Oxford Arthroplasty Early Change Score (OACS), a Patient Reported Assessment Measure also developed under the same FDA guidelines and applicable to the same patient population. ‘The two measures give a snapshot of both patient perceived outcomes at the time taken and also improvement, or change, since the surgery.

The OARS can also be used as an ‘acute’ perioperative measure of recovery in combination with the Oxford Hip and Knee Scores, with their longer-term recall periods.

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The development of the OARS was funded in part by Sigma Theta Tau International Honor Society of Nursing.

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Administration Methods

The OARS is to date validated for pen and paper completion. Careful migration to a digital delivery format (for example screen based device) can be authorised. Please contact us for advice.

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