Correlation Between Patient-Reported "Happiness" With Knee Range of Motion and Objective Measurements in Primary Knee Arthroplasty.

Abstract

The purpose of this study was to evaluate the correlation between objective knee range of motion (ROM) and patient "happiness" with knee ROM after total knee arthroplasty. This was a retrospective review of all primary total knee arthroplasties from June through December 2019, yielding 902 patients (1,009 knees). Records were reviewed for knee ROM preoperatively and postoperatively at 6-week follow-up as well as whether patients self-reported being "Happy with their ROM" (HWROM). Clinical records were reviewed for documents ROM as well as manipulation under anesthesia (MUA). The mean preoperative ROM was 110 ± 16 degrees, and 40% of patients were happy with their ROM. Postoperatively, the mean ROM was 106 ± 13 degrees (P < .001), and 76% of patients were HWROM (P < .001). The mean change in knee ROM was (-) 5 ± 17 degrees. The mean postoperative ROM and change in ROM of patients who were HWROM after surgery were 109 ± 12 degrees and (-)2 ± 16 degrees. In patients not HWROM postoperatively, the mean ROM and change in ROM were 98 ± 14 degrees and (-)12 ± 18 degrees (P < .001). Patients with a lower preoperative ROM were statistically significantly more likely to have a positive change in their HWROM (f ratio = 41, P < .001). MUAs were performed in 7.2% of knees, and 28% of patients who underwent an MUA were HWROM before MUA. Early postoperative knee ROM was correlated with patient HWROM. However, further longer term follow-up and more detailed analysis of patient happiness with ROM are needed.