Five-Year Risk of Conversion to Total Knee Arthroplasty After Operatively Treated Periarticular Knee Fractures in Patients Over 40 Years of Age

Background: Periarticular knee fractures present a significant challenge to minimize post-traumatic osteoarthritis. The purpose of this study is to compare the rates of conversion to total knee arthroplasty (TKA) for different periarticular knee fractures, investigate the rate of knee injections as a more rapid assessment of knee symptoms, and identify risk factors that lead to conversion to TKA following periarticular fractures.

Methods: A comprehensive retrospective review of the Humana administrative claims database was performed. A total of 2813 patients greater than 40 years of age with diagnosis code for tibial plateau fracture or distal femur fracture linked to a Current Procedural Terminology code of open reduction internal fixation between 2007 and 2011 were evaluated. The rates of TKA and knee injections within 5 years were compared. Cox proportional hazards model was used to evaluate risk factors for conversion.

Results: Of 2813 periarticular fractures, the 5-year rate of conversion to TKA was 3.3%. The rate of conversion for tibial plateau fractures was significantly higher at 4.5% compared to 2.3% for distal femur fractures (P = .001). Tibial plateau fracture, obesity, and female gender were risk factors found to portend an increased risk of conversion to TKA with hazard ratios of 1.77, 1.69, and 1.88, respectively. The overall rate of knee injections was 12.8% with an average time to injection of 18.2 months after open reduction internal fixation.

Conclusion: The rate of conversion to TKA for periarticular knee fractures overall was 3.3%, while the rate of knee injections within 5 years of surgery was 12.8%, suggesting a not insignificant minority of patients require treatment for symptomatic knee pain.

Level of evidence: Therapeutic Level III.