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Severe Coronal Plane Deformity Correction in Total Knee Arthroplasty Is Associated With Increased Surgeon Physiologic
Derek J Matheson1, Robert A Burnett2, Claire R Kapron1
1Department of Orthopaedic Surgery, University of Utah Salt Lake City, Salt Lake City, Utah.
Background:
Coronal plane deformity in total knee arthroplasty (TKA) can introduce major variability in difficulty between cases based on the type and degree of deformity. The purpose of this study was to compare the energy expenditure of TKA in varus and valgus knees.
Methods:
There were 85 patients undergoing primary, elective cemented TKA who were prospectively enrolled, and various demographic and surgical variables were collected. Surgeon physiologic parameters were collected via a smart garment that recorded heart rate variability (beats per minute), minute ventilation (mL/minute), and energy expenditure (kcal). Patients who had coronal plane deformities of various degrees were stratified into different groups based on severity: mild varus (N = 31), moderate/severe varus (N = 28), mild valgus (N = 17), and moderate/severe valgus (N = nine). A coronal plane deformity of 10° was the threshold for moderate/severe deformity. Analysis of variance models were used to compare demographics and surgeon physiologic stress between groups. There were differences in age and sex between cohorts (P < 0.05), whereas other demographics were comparable (P > 0.05).
Results:
Energy expenditure was significantly different across deformities, with valgus knees and increased deformity having the highest expenditure (P < 0.001). Heart rate variability and minute ventilation did not differ across cohorts (P = 0.23). In the regression models, energy expenditure remained significantly higher with mild (P = 0.017) and moderate/severe valgus (P = 0.001) compared to mild varus. Heart rate variability was also significantly increased in these groups (P = 0.03).
Conclusions:
Surgeons expend varying degrees of energy during TKA depending on the type and degree of deformity. Total knee arthroplasty in the setting of severe valgus deformity is associated with the most physiologic demand for the surgeon. These data provide quantifiable measures for the degree of case difficulty, which is pertinent for proper compensation for appropriate work.
