Total Joint Arthroplasty Volume in the Military Health System

Introduction: The relationship between volume and outcome of total knee arthroplasties is a concern in both the civilian and military patient populations. We sought to compare surgeons and hospital procedure volumes performed on military service members and define factors leading to increased civilian referrals.

Materials and methods: The Military Health System Data Repository (MDR) contains patient information on all healthcare beneficiary encounters, including care provided both in Military Health System (MHS) facilities and in civilian network facilities. The Military Analysis and Reporting Tool (M2) queried the MDR for all patients between 2011 and 2015 with a CPT code for hip or knee arthroplasty associated with a provider HIPAA taxonomy code for orthopedic surgery. M2 enrollee encounters were used to calculate the total number of arthroplasty procedures performed by both military and civilian orthopedic surgeons on MHS enrollees as well as the incidence rate of arthroplasty procedures. Logistic regression was used to predict which cases were more likely to have been treated at military treatment facilities using patient gender, sponsor service branch, age, and beneficiary category.

Results: During the study period, a total of 12,627 military facility arthroplasty cases and a total of 142,637 civilian facility arthroplasty cases were performed on TRICARE enrolled patients. The total number of military surgeons performing arthroplasty on TRICARE enrolled patients was 323, while the total number of civilian surgeons performing arthroplasty was 10,245 during the same time period; the number of military surgeons performing arthroplasty on active duty patients was 176, and the total number of civilian surgeons performing arthroplasty on military patients was 1045. Overall, including retirees and activity duty service members, more procedures are performed by civilian network surgeons than military surgeons in all states. In an adjusted model, male patients were slightly more likely to receive care at an military treatment facilitie than female patients (OR = 1.47, 95% CI: 1.41-1.53). Furthermore, with respect to service, patients with Air Force (OR: 1.08, 95% CI: 1.02-1.15) and Navy sponsors (OR: 1.61, 95% CI: 1.51-1.71) were more likely to receive military care than patients with Army sponsors.

Conclusions: Based on our findings, we recommend the MHS focus attention to recapturing the Army active duty male patients who are more likely to receive care outside of the military healthcare network. Further analysis of the many factors including, but not limited to, referral process for total joint arthroplasty, time to procedure, and facility resources is required, in addition to assessing patient outcomes following the procedures.