The ceiling effects of patient reported outcome measures for total knee arthroplasty - 31/12/20

Doi : 10.1016/j.otsr.2020.102758

Lukas Eckhard ^a,^b,⁎ , Selin Munir ^b, David Wood ^c, Simon Talbot ^d, Roger Brighton ^e, Bill Walter ^f, Jonathan Baré ^g
^a Department of Orthopaedics and Traumatology, University Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany
^b Australian Institute of Musculoskeletal Research, Sydney, Suite 1.08 Mater Clinic Building, 3-9 Gillies Street, Wollstonecraft NSW 2065, Australia
^c North Sydney Orthopedics and Sport Medicine Centre, Sydney, Suite 2 Mater Clinic Building, 3-9 Gillies Street, Wollstonecraft NSW 2065, Australia
^d Orthopaedic Department, Western Health, Melbourne, Suite 1, 210 Burgundy Street, Heidelberg VIC 3084, Australia
^e Westmead Private Hospital Sydney, Suite 12, 16-18 Mons Rd, Westmead NSW 2153, Australia
^f Royal North Shore Hospital Sydney, Ground Floor, Kolling Building 10 Westbourne St, St Leonards NSW 2065, Australia
^g Melbourne Orthopaedic Group Melbourne, 33 The Avenue, Windsor 3181 Victoria, Australia

^⁎Corresponding author. Department of Orthopaedics and Traumatology, University Medical Center of the Johannes-Gutenberg University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.Department of Orthopaedics and Traumatology, University Medical Center of the Johannes-Gutenberg University MainzLangenbeckstrasse 1Mainz55131Germany

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Abstract

Background

Patient reported outcome measurements (PROMs) that exhibit a substantial ceiling effect show clustering of participant's scores towards the upper limit of a scale and consequently have low discriminatory power among high end scores. This study aimed to compare ceiling effects at 1 and 2 years postoperatively across commonly usedPROMs for TKA.

Hypothesis

We hypothesized, that the analyzed PROMs differ substantially in regards to their ceiling effect.

Patients and methods

Patients that underwent a primary unilateral TKA and completed pre-operative and post-operative questionnaires were included in the analysis. Participants completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC and OKS preoperatively, and completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC,OKS and FJS postoperatively at 1 and 2 years.

Results

1-year and 2-year follow-up data was available for 380 and 193 patients, respectively. The preoperative mean age was 68.0 (8.5) and mean BMI was 31.4kg/m² (6.6), with a male to female ratio of 49.6% to 50.4%. At 1 year postoperatively, a ceiling effect was seen for the Pain and ADL subscales of the KOOS and the KOOS JR. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a ceiling effect at 2 years postoperatively. We found 9.0% and 14.8% of patients achieving a maximum score in the FJS at 1 and 2 years, respectively, indicating the absence of a substantial ceiling effect.

Conclusion

The PROMs studied differ substantially with regards to their ceiling effect and consequently their ability to detect differences between well performing groups. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a substantial ceiling effect at 2 years postoperatively. We recommend using PROMs like the FJS and KOOS-12 with a more evenly distribution of scores across the scale when studying well performing cohorts.