The Effect of Comorbidities on Outcomes following Total Knee Arthroplasty

To enhance the success of total knee arthroplasty (TKA), clinicians must identify factors that may impede functional recovery. Multiple comorbidities may affect outcomes, and our purpose was to identify the role of overall disease burden, as well as individual comorbidities, on post-TKA outcomes. We prospectively reviewed 283 TKA patients (172 women, 111 men). Preexisting comorbidities were weighted using the Charlson comorbidity index (CCI). Patients were divided into four groups: CCI score of 0 to 1, 2, 3, or 4 or more and followed up at 6 weeks, 3 months, 1year, and annually until 5 years. The most prevalent comorbidities were also individually assessed at these follow-ups. The effect of these on outcomes was evaluated using the Knee Society Score (KSS), Short Form 36 (SF-36), and lower extremity activity scale (LEAS). Patients who had lower CCI scores had significant improvements in KSS at 2- and 5-year follow-up (+34 and +38 points, respectively; p<0.01). CCI scores of 0 to l demonstrated significantly greater improvement in the SF-36 physical component score (PCS) at final follow-up (+16 points; p<0.05) and higher LEAS scores at 2 years postoperatively (p=0.001), compared with the remaining cohorts. Endocrine disease and hypertension yielded significantly lower KSS at follow-up (-5 and -5 points, respectively; p<0.05). Patients who had hypertension or gastrointestinal disease had significantly lower SF-36 PCS at final follow-up compared with those who did not (45 vs. 48 points and 47 vs. 49 points; p<0.035 and 0.041, respectively), as well as lower activity scores (11 vs. 12 points for both comorbidities; p<0.05). Patients who had cardiovascular disease had significantly lower SF-36 MCS (53 vs. 56 points, respectively; p=0.03) at 4 years postoperatively than those without, as well as lower activity scores (11 vs. 12 points, respectively; p=0.024). Patients who have lower CCIs may have improved activity and functional levels following TKA. Hypertension, cardiovascular disease, endocrine disease, and gastrointestinal disease may correlate with poorer functional and activity outcomes postoperatively.