Increasing age and various comorbidities are known risk factors for complications after total knee arthroplasty (TKA), but data on the impact of total comorbidity burden is scarce. We investigated the effect of age and total comorbidity burden on outcomes after primary TKA in octogenarians (OGs).
A matched-pair comparison study was conducted using prospectively collected TKA registry data in a large tertiary institution. Between 2006 and 2011, consecutive OGs undergoing primary unilateral TKA, with minimum 2-year follow-up, were matched 1:1 with younger controls based on demographic and surgical variables. We compared the Charlson comorbidity index (CCI), complication rate, length of stay (LOS), 30-day readmission, and 2-year reoperation rate. Multivariate analysis was performed to determine the effects of age and CCI on each outcome.
There were 209 OGs and 209 controls. OGs were significantly older (mean age 82.1 vs 66.1 years, P < .001) and had higher CCI. OGs had longer mean LOS (6.3 vs 5.4 days, P = .001), and a trend for more complications and readmissions. The complication rate increased from 7.5% for CCI = 0, to 33.3% for CCI ≥3 (P = .005). The LOS increased from 5.4 days for CCI = 0, to 9.6 days for CCI ≥3 (P < .001). Multivariate analysis showed that higher CCI was an independent risk factor for complications and longer LOS, whereas age was not.
Comorbidity burden has a greater impact than age alone on TKA outcomes in OGs. Well-selected OGs remain good candidates for TKA.