# Observed Differences in Patient Comorbidities and Complications Undergoing Primary Total Joint Arthroplasty Between Non-orthopaedic and Orthopaedic Referral Patients

## TL;DR

This study found that patients referred by orthopaedic surgeons for joint replacement surgery had more health issues and complications compared to those referred by non-orthopaedic doctors.

## Contribution

The study reveals how referral type affects patient health profiles and complications in joint replacement surgery under value-based reimbursement.

## Key findings

- Orthopaedic referrals had higher rates of obesity and severe comorbidities compared to non-orthopaedic referrals.
- Patients from orthopaedic referrals experienced more wound complications and multiple complications post-surgery.
- The findings suggest potential monetary incentives may influence surgeon referral patterns.

## Abstract

Background: Value-based total joint arthroplasty (TJA) has resulted in decreasing surgeon reimbursement which has created concern that surgeons are being incentivized to avoid medically complex patients. The purpose of this study was to determine if patients who underwent primary total knee (TKA) and total hip arthroplasty (THA) had different comorbidities and complication rates based on referral type: 1) non-orthopaedic referral (NOR), 2) outside orthopaedic referral (OOR) or 3) self-referral (SR).

Methods: At a single tertiary care centre, patients undergoing primary TJA between July 2019 and January 2020 were identified using current procedural codes. Data were abstracted from the Institutional National Surgical Quality Improvement Program (NSQIP) along with electronic medical records which included referral type, primary insurance, demographics, comorbidities, and comorbidity scores, including an American Society of Anesthesiology (ASA) score. Complications and outcomes were tracked for 90 days post-operatively. Referral groups were compared using Chi-square exact tests for categorical variables and t-tests or Wilcoxon Rank Sum tests for continuous variables, as appropriate.

Results: Of the 393 patients included in this study, there were 249 (63%) NOR, 104 (26%) OOR, and 40 (10%) SR. The OOR versus NOR group had a significantly greater proportion of patients with obesity (79 vs 64%, p=0.047) and an ASA score ≥3 (59 vs 43%, p=0.007). There was a significantly greater proportion of patients with wound complications (10 vs 4%, p=0.023) and ≥2 complications (14 vs 3%, p<0.001) in OOR versus NOR, respectively.

Conclusion: Patients who underwent primary TJA and were referred by an orthopaedic surgeon tended to have more comorbid conditions and higher rates of severe complications. The observed difference in referrals may be explained by monetary incentivization in the context of current reimbursement trends. Organizations utilizing bundled payment programs to reimburse surgeons should use a risk-stratification model to mitigate incentivizing surgeons to avoid medically complex patients.