Outcomes After Total Knee Arthroplasty in Patients With a History of Patella Fracture: A Propensity Score–Matched Analysis

Background: Posttraumatic osteoarthritis is a common indication for total knee arthroplasty (TKA). The purpose of this study was to evaluate the association between a history of patella fracture and postoperative complication rates after TKA. Methods: Patients diagnosed with a patella fracture before undergoing TKA were identified from a large national database and matched to a control cohort using propensity scoring. Rates of medical complications occurring within 90 days of TKA and surgery-related complications occurring within 1 year of TKA were compared using odds ratios. Healthcare utilization outcomes including 90-day emergency department (ED) presentation, hospital readmission, and total cost were also compared. Results: Compared with a propensity-matched control cohort, TKA patients with a history of patella fracture had a lower incidence of pulmonary embolism (OR 0.74, P = 0.0442) and higher incidences of periprosthetic joint infection (OR 1.68, P < 0.0001), revision surgery (OR 1.84, P < 0.0001), dislocation (OR 1.61, P = 0.026), lysis of adhesions (OR 2.21, P = 0.0082), and wound disruption (OR 1.52, P < 0.0001). A history of patella fracture was also associated with an increased rate of ED presentation (OR 1.08, P = 0.0454) and increased total cost ($14,359 vs. $12,786, P = 0.0003). Conclusion: A history of patella fracture is associated with early surgery-related complications after TKA including periprosthetic joint infection, revision surgery, dislocation, lysis of adhesions, and wound disruption. Healthcare utilization is increased among these patients with higher rates of ED presentation and increased total cost. These findings allow for more accurate risk stratification and counseling of patients. Level of evidence: III, Retrospective review.