Increasing comorbidity postoperatively is associated with worsening physical function and pain after total knee arthroplasty (TKA), a recent study found. Researchers performed a retrospective chart review of veterans who had completed Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form-36 (SF36) surveys at regular intervals after primary TKA. Comorbidity was assessed using a variety of scales. The study cohort consisted of 124 patients with a mean age of 71.7 (SD 6.9) years, followed for a mean of 4.9 years post-operatively (SD 2.8). They found:

• Post-operative worsening of the Charlson Index score was significantly associated with worsening SF36 Physical Function (PF), and WOMAC PF subscale scores, in the subsequent periods.
• Worsening novel medical index subscale scores were significantly associated with worsening SF36 PF scores, SF36 BP, and showed a non-significant trend for worse WOMAC PF scores subsequently.
• TKA complications, as assessed by TKA-related index subscale, were not significantly associated with SF36 or WOMAC domain scores.