Thresholds for Oxford Knee Score after total knee replacement surgery: a novel approach to post-operative evaluation

Christian Lund Petersen,Nicolai Kjærgaard,Jonas Bruun Kjærsgaard,Michael Ulrich Jensen,Mogens Berg Laursen

doi:10.1186/s13018-017-0592-1

Christian Lund Petersen, Nicolai Kjærgaard + Show 3 more

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https://doi.org/10.1186/s13018-017-0592-1

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Abstract

BackgroundIn a prospective cohort study, we wanted to detect thresholds distinguishing between patients with a satisfactory and an unsatisfactory outcome after total knee replacement (TKR) based on Patient-Reported Outcome Measures (PROMs), namely the Oxford Knee Score (OKS), using patient satisfaction and patient-perceived function as global transition items.MethodsSeventy-three TKR patients completed the OKS questionnaire before surgery and were invited to complete the same questionnaire again 6 (4 to 9) months after surgery. Correlations between outcome measures and anchors were calculated using Pearson’s correlation coefficient. Thresholds were established by receiver operating characteristics (ROC) analysis, using multiple anchor-based approaches.ResultsPatients showed a mean increase of 16.5 (SD 9.5) in OKS following TKR. Significant positive correlations were found between outcome measures and anchors. Six different thresholds were determined for outcome measures coupled with satisfaction, patient-perceived function and a combination thereof using a cut-off of 50 and 70.ConclusionsThis study has established a set of clinically meaningful thresholds for Oxford Knee scores that may help to detect TKR patients who might be in need of post-operative evaluation.

Highlights

In a prospective cohort study, we wanted to detect thresholds distinguishing between patients with a satisfactory and an unsatisfactory outcome after total knee replacement (TKR) based on Patient-Reported Outcome Measures (PROMs), namely the Oxford Knee Score (OKS), using patient satisfaction and patient-perceived function as global transition items
Post-operative improvements The present study found TKR patients to undergo a mean improvement in OKS of 16.5, which is consistent with findings in other studies
In line with the objectives of this paper, we have established a set of thresholds for the Oxford Knee Score that can be used to identify patients in need of post-operative evaluation

Summary

Introduction

In a prospective cohort study, we wanted to detect thresholds distinguishing between patients with a satisfactory and an unsatisfactory outcome after total knee replacement (TKR) based on Patient-Reported Outcome Measures (PROMs), namely the Oxford Knee Score (OKS), using patient satisfaction and patient-perceived function as global transition items. Joint-specific PROMs allow the assessment of the outcome from the perspective of the patient, including the level of pain and function of the specific joint. One approach is called the minimal clinically important difference (MCID), which is defined as “the smallest change that is important to patients” [8]. Another approach is calculating a threshold of the postoperative OKS value, providing another perspective of patient-perceived outcome

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