PATIENT REPORTED OUTCOME DIFFERS TO ASSESSMENT OF PHYSICAL FUNCTION FOLLOWING TOTAL KNEE ARTHROPLASTY

DF. Hamilton[1], AHRW. Simpson[1,2], P. Gaston[2]

[1] Edinburgh Orthopaedic Engineering Collaboration, University of Edinburgh, UK [2] Royal Infirmary of Edinburgh, UK

Purpose To examine the relationship between physical outcome and patient report of outcome following total knee arthroplasty (TKA). Relevance Increasingly Patient Reported Outcome Measures (PROMS) are used to assess function following TKA. It is assumed that these measures accurately reflect the patient’s pain and physical function, however, evidence is emerging that this may incorrect1,2. Methods Approval was granted by the Local Research Ethics Committee, and 26 consecutive patients listed for TKA were assessed pre TKA, and at 8 and 26 weeks post-operation. The Oxford Knee Score (OKS) and the physical function score (PCS) of the Short Form-36 were utilised as self report outcomes. Direct measurement of leg strength was assessed (Leg extensor Power Rig TM). Timed assessment of functional tasks was performed (Automated Locomotor Function, ALF). Pain scores were recorded by numerical rating scale. Results All the individual measures showed statistically significant improvement between each of the assessment periods (paired sample t-test, p = <0.05). The PROMS however were found to correlate poorly to the physical assessments. The OKS correlated poorly with the ALF, (r = < 0.5) and with leg strength (r = < 0.3).The PCS correlated poorly with ALF (r = < 0.2) and with leg strength (r = 0.34). Conclusions These results suggest that PROMS do not fully represent actual physical function following TKA. With the advancement of PROMS in the literature, it is important to recognise that the assessment they provide may be incomplete. A larger study would be beneficial to assess this issue fully.

Support

This work forms part of a PhD award with is jointly funded by the Medical Research Council and Stryker UK

References

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