While serum interleukin-6 (IL-6) clearly has been established as a marker of physiologic stress, the validity of IL-6 as a reliable measure of the degree of trauma or stress suffered by an individual with total knee replacement (TKA) remains in question. We hypothesized that if serum IL-6 is a marker of surgical stress, then we would observe marked increases in IL-6 levels in sequential bilateral TKA as compared with unilateral TKA.
The study design was a single-surgeon prospective case-control pilot study of sequential bilateral TKA cases and unilateral TKA controls to assess changes in serum IL-6 levels preoperatively, during, at wound closure, and up to 48 hours postoperatively. IL-6 levels were analyzed using a one-way mixed models analysis of variance.
Eleven patients with unilateral and 12 with bilateral TKA comprised the study sample. IL-6 levels at peak (24 hours postoperatively) for the unilateral control group was 12 times higher compared with baseline (4.6 pg/mL compared with 55.0 pg/mL), while the bilateral TKA group saw a 116-fold increase in IL-6 from baseline to peak at 12 hours postoperatively (2.9 pg/mL compared with 335.0 pg/mL). At “peak,” IL-6 was 6.1 times higher for the bilateral group compared with the unilateral group.
This pilot study supports the notion that sequential bilateral TKA produces a far greater surgical stress, as measured by IL-6. Careful patient selection, counseling, and consideration of staging procedures are advised.
aHamilton Arthroplasty Group, Hamilton Health Sciences Juravinski Hospital, Hamilton, Ontario, Canada
bMcMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada
cThrombosis and Atherosclerosis Research Institute, David Braley Cardiac Vascular and Stroke Research Institute, Hamilton Health Sciences General Hospital, Hamilton, Ontario, Canada
dDepartment of Orthopaedic Surgery, Halton Healthcare Services Oakville-Trafalgar Memorial Hospital, Oakville, Ontario, Canada
Financial Disclosure: The authors report no financial conflicts of interest.
Correspondence to Danielle Petruccelli, MLIS, Hamilton Arthroplasty Group, Hamilton Health Sciences Juravinski Hospital, Hamilton, Ontario, Canada L8V 1C3 Tel: +905 527 4322 ext 42296; fax: +905 389 5617; e-mail: firstname.lastname@example.org