Prior Nonarthroplasty Surgery Increases Risk of Complication in Primary Total Knee Arthroplasty.

Background: Prior ipsilateral knee surgery may increase the risk for complications after total knee arthroplasty (TKA). It remains unclear if the extent of previous surgery affects those risks disparately. The purpose of this study is to evaluate prior nonarthroplasty bony procedure (BP) and soft tissue only procedure (STP) as a potential risk factor for complications after TKA and determine the association with charges or reimbursement of the primary TKA.

Methods: Patients who underwent primary TKA with previous knee surgery were identified using a national Medicare database and matched 1:5 to controls without prior knee surgery. Rates of postoperative medical and surgical complications were calculated in addition to hospital-associated charges and reimbursements. Logistic regression analysis was used to control for confounding factors.

Results: Patients who underwent BP (n = 835) had increased risk of readmission (58.6% vs 45.3%, odds ratio (OR) 1.72, 95% confidence interval (CI) 1.59-1.85, P < .001) and emergency room visits (14.5% vs 10.4%, OR 1.44, 95% CI 1.29-1.61, P = .001). Patients who underwent STP (n = 6766) had increased risk of readmission (58.1% vs 45.2%, OR 1.69, 95% CI 1.64-1.73, P < .001), emergency room visits (12.6% vs 0.7%, OR 1.33, 1.28-1.39, P < .001), revision (1.8% vs 1.4%, OR 1.33, 95% CI 1.21-1.47, P = .006), cerebrovascular accident (2.3% vs 1.7%, OR 1.33, 95% CI 1.22-1.46, P = .002), and venous thromboembolism (3.8% vs 3.2%, OR 1.21, 95% CI 1.13-1.29, P = .009). Prior surgery was associated with increased charges and reimbursements.

Conclusion: Prior ipsilateral knee surgery is associated with significantly increased risks of postoperative complications after primary TKA. Interestingly, previous STP but not BP increased the risk of short-term revision and venous thromboembolism.