Underlying diagnosis predicts patient-reported outcomes after revision total knee arthroplasty.

OBJECTIVE: To assess the association of underlying diagnosis with outcomes after revision total knee arthroplasty (TKA).

METHODS: For this cohort study we used prospectively collected data from the Mayo Clinic Total Joint Registry on all revision TKA patients from 1993 to 2005 with 2- or 5-year response to a validated knee questionnaire that assesses pain and function. We used logistic regression to assess the odds of moderate-severe activities of daily living (ADL) limitations and moderate-severe index knee pain 2 and 5 years after revision TKA. Odds ratios (ORs) and 95% CIs are presented.

RESULTS: The underlying diagnosis for the 2- and 5-year cohorts was loosening, wear or osteolysis in 73% and 75%; dislocation, bone or prosthesis fracture, instability or non-union in 17% and 15%; and failed prior arthroplasty with components removed or infection in 11% and 11%, respectively. In multivariable adjusted analyses that included preoperative status, compared with patients with loosening/wear/osteolysis, patients with dislocation/fracture/instability/non-union had an OR of 2.1 for moderate-severe ADL limitation (95% CI 1.3, 3.1, P < 0.001) and those with failed prior arthroplasty/infection had an OR of 1.1 (95% CI 0.6, 1.8, P = 0.4). At 5 years, differences were no longer significant. In multivariable adjusted analyses, compared with patients with loosening/wear/osteolysis, patients with dislocation/fracture/instability/non-union had an OR of 2.0 for moderate-severe pain (95% CI 1.3, 3.1, P < 0.01) at 2 years and an OR of 2.1 (95% CI 1.3, 3.8, P = 0.01) at 5 years. Failed prior arthroplasty/infection was not significantly different than the reference category.

CONCLUSION: Underlying diagnosis is independently associated with ADL limitations and pain after revision TKA. This information can help patients have realistic expectations of outcomes.