Metric Selection, Metric Targets, and Risk Adjustment Should be Considered in the Design of Gainsharing Models for Bundled Payment Programs in Total Joint Arthroplasty.

BACKGROUND: Under bundled payment models, gainsharing presents an important mechanism to ensure engagement and reward innovation. We hypothesized that metric selection, metric targets, and risk adjustment would impact surgeons' performance in gainsharing models. METHODS: Patients undergoing total joint arthroplasty at an urban health system from 2017 to September 2018 were included. Gainsharing metrics included the following: length of stay, % discharge-to-home, 90-day readmission rate, % of patients with episode spend under target price, and % of patients with patient-reported outcomes (PROs) collected. Four scenarios were created to evaluate how metric selection/adjustment impacted surgeons' performance designation: scenario 1 used "aspirational targets" (>60th percentile), scenario 2 used "acceptable targets" (>50th percentile), scenario 3 risk-adjusted surgeon performance prior to comparing aspirational targets, and scenario 4 included a PRO collection metric. Number of metrics achieved determined performance tier, with higher tiers getting a greater share of the gainsharing pool. RESULTS: In total, 2776 patients treated by 12 surgeons met inclusion criteria (mean length of stay 3.0 days, readmission rate 4.0%, discharge-to-home 74%, episode spend under target price 85%, PRO collection 56%). Lowering of metric targets (scenario 1 vs. 2) resulted in a 75% increase in the number of high performers and 98% of the gainsharing pool being eligible for distribution. Risk adjustment (scenario 3) caused 50% of providers to move to higher performance tiers and potential payments to increase by 28%. Adding the PRO metric did not change performance. CONCLUSION: Quality metric/target selection and risk adjustment profoundly impact surgeons' performance in gainsharing contracts. This impacts how successful these contracts can be in driving innovation and dis-incentivizing the "cherry picking" of patients. LEVEL OF EVIDENCE: Level III.

Does Productivity-Based Physician Compensation Affect Surgical Rates for Elective Arthroplasty Surgery?

BACKGROUND: Surgeon compensation models could potentially influence the utilization of elective procedures. We assessed whether transitioning from salaried to a relative value unit (RVU) productivity-based physician compensation model changed the surgical rate and patient selection in elective total hip and knee arthroplasty (THA and TKA) procedures. METHODS: Our institution transitioned from salaried to RVU productivity-based reimbursement in July 2016. We performed a retrospective analysis on patients undergoing primary THA and TKA from July 2014 to July 2018 before and after the transition (salary period n = 820; RVU period n = 1188). Beta regression was used to determine the reimbursement structure as a predictor of surgery. The surgical rate was defined as the number of primary THA and TKA procedures per reimbursement period divided by all arthroplasty and osteoarthritis outpatient clinic encounters. RESULTS: There was a surgical rate of 15.8% (95% confidence interval [CI] 13.8%-17.8%) THA and 16.7% (95% CI 15.1%-18.1%) TKA procedures during RVU reimbursement compared to 11.1% (95% CI 9.8%-12.8%) THA and 11.7% (95% CI 10.5%-12.8%) TKA procedures during the salaried period (P < .001). The adjusted odds of undergoing a THA or TKA procedure increased in the RVU compared to the salaried model (THA odds ratio 1.48, 95% CI 1.43-1.53; TKA odds ratio 1.50, 95% CI 1.46-1.55; P < .001). There were no significant differences in patient age, gender, race, body mass index, or Charlson Comorbidity Index in salaried vs RVU productivity periods (P > .05 for all covariates). CONCLUSIONS: Productivity-based physician compensation may encourage higher rates of elective arthroplasty procedures without broadening patient selection.

Biomimetic hydrogels with immobilized ephrinA1 for therapeutic angiogenesis.

The formation of a microvasculature is regulated in large part by cell-cell interactions. Ephrins and their Eph receptors mediate cell adhesion, repulsion, and migration, all critical processes in angiogenesis. (1) Here we use a covalently immobilized ephrinA1, conjugated to poly(ethylene glycol), to induce vessel formation both in vitro and in vivo in poly(ethylene glycol) diacrylate (PEGDA) hydrogels. Human umbilical vein endothelial cell (HUVEC) tubulogenesis in matrix metalloproteinase-sensitive hydrogels was visualized from 6 h to 7 days in response to three different concentrations of PEG-ephrinA1. The deposition of extracellular matrix proteins collagen IV and laminin that stabilize tubule formation were imaged, quantified, and found to be dependent on PEG-ephrinA1 concentration. To confirm the importance of the EphA2-ephrinA1 interaction in tubule formation, soluble EphA2 was used to disrupt the EphA2-ephrinA1 interaction between a coculture of HUVEC and human brain vascular pericyte cells. HUVECs seeded onto PEGDA hydrogels displayed a dose-dependent reduction in tubule formation in response to the soluble EphA2. Finally, hydrogels with releasable platelet-derived growth factor (PDGF), immobilized RGDS, and covalently immobilized PEG-ephrinA1 were implanted into the mouse cornea micropocket. These hydrogels induced a more robust vascular response with an increase in vessel density as compared with hydrogels with releasable PDGF alone. As such, PEG-ephrinA1 may represent a promising molecule to regulate cell adhesion and migration for formation of a microvasculature in tissue-engineered constructs.