Conversion Total Knee Arthroplasty After Tibial Plateau Fixation Is Associated With Lower Reimbursement, Greater Complication Rates, and Similar Opioid Use

Objective

Total knee replacement after previous open reduction and internal fixation for tibial plateau fracture (conversion total knee) increases the complexity of the procedure and the complication rate. However, very little research exists to report on opioid use and cost associated with total knee arthroplasty (TKA) following tibial plateau fracture fixation as compared to primary TKA patients with no history of tibial plateau fracture. The aim of this study is to compare the differences in opioid use, reimbursements, and complication rates between patients with and without a history of tibial plateau fracture undergoing TKA.

Methods and materials

This is a retrospective large database review study. The study included patients across the country and in various clinical settings including, but not limited to, institutions, primary and tertiary care centers, and private practice. The PearlDiver database was reviewed for patients undergoing TKA between 2010 and 2019. Patients who underwent TKA following surgical repair of a tibial plateau fracture were identified using Common Procedural Terminology (CPT) codes and the appropriate International Classification of Diseases Ninth and Tenth Revision (ICD-9, ICD-10) codes. This group was then matched by age, gender, Charleston Comorbidity Index (CCI) score, Elixhauser Comorbidity Index (ECI) score, obesity, tobacco use, and diabetes to a group of similar patients who underwent TKA with no history of tibial plateau fracture. Opioid use over the episode of care, evaluated by morphine milligram equivalents (MME), and 30-day reimbursed cost were compared between groups using an unequal variance t-test. Complication rates at 30 days, 90 days, and one year postoperatively, and revision rates at one and two years postoperatively were compared using the odd’s ratio (OR) with 95% confidence intervals (95%CI).

Results

The episode of care cost for TKA was significantly lower for patients with a history of tibial plateau fracture ($11,615 ± $15,704) than it was for patients without a history of tibial plateau fracture ($16,088 ± $18,573) (p = 3.56E-14). At 30 days after knee arthroplasty, patients with a history of tibial plateau fracture had significantly more episodes of dehiscence (OR 2.665 [95% CI 1.327-5.351]; p = 0.006) and surgical site infection (SSI) (OR 1.698 [95% CI 1.058-2.724]; p = 0.028), which was significant at 90 days postop for both dehiscence (OR 1.358 [95% CI 0.723-2.551]; p = 0.001) and SSI (OR 1.634 [95% CI 1.100-1.802]; p = 0.015), as well as mechanical complications of the implant device (OR 2.420 [95% CI 1.154-5.076]; p = 0.019). There was no significant difference in the number of opioids prescribed postoperatively to patients with a history of tibial plateau fracture (2218 ± 3255 MME) compared to those without prior tibial plateau fracture (2400 ± 4843 MME) (p = 0.258). However, there was a small but statistically significant increase in the number of days postoperatively patients with a history of tibial plateau fracture were prescribed opioids (11.99 ± 7.73 days) compared to non-tibial plateau fracture patients (11.15 ± 7.18 days) (p = 0.004).

Conclusion

Patients with a history of tibial plateau fracture who then underwent conversion TKA have a lower reimbursed cost of TKA but a higher postoperative risk for dehiscence, mechanical complications, and surgical site infections. There is no significant difference in postoperative opioid use between the two groups.