Drivers of Day-of-Surgery Cost Variation in Augmented Rotator Cuff Repair: A Time-Driven Activity-Based Costing Analysis

Background Augmentation strategies are used in high-risk rotator cuff tears; however, intraoperative cost variation associated with augmentation remains poorly defined. Time-Driven Activity-Based Costing (TDABC) provides assessment of day of surgery (DOS) resource utilization and may clarify drivers of cost variation. The aim was to quantify DOS costs of augmented rotator cuff repair (RCR) using a TDABC framework and to identify independent drivers of cost variation. The secondary aim was to evaluate the association between biologic risk, as measured by the modified Rotator Cuff Healing Index (RoHI), and intraoperative resource utilization in a matched cohort with available preoperative MRI. Methods A retrospective study of patients who underwent RCR between 2017 and 2025 across two academic centers. 79 augmented RCR cases were stratified by fixation technique. DOS cost was calculated using TDABC framework. Cost outcomes were summarized as median (interquartile range); unadjusted between-group comparisons were performed using generalized linear models with a gamma distribution and log link. Multivariable analysis was performed using a generalized linear model with gamma distribution and log link. The model adjusted for fixation technique, operative time, institution, age, sex, ASA classification, and smoking status. RoHI score was included among patients with MRI data. A stratified anchor analysis compared cost and operative time by RoHI tier (<5 or ≥5). Results Among 79 augmented cases, 45 (57.0%) utilized collagen xenograft patch and 34 (43.0%) utilized dermal allograft. Collagen xenograft patch was associated with higher implant cost (estimated marginal mean $6,611 vs $4,681, p<0.001) and higher total DOS cost ($9,712 vs $7,297, p<0.001). In multivariable gamma regression analysis, fixation technique, operative duration, and institution were independently associated with total DOS cost. Additional operative minute was associated with a 0.2% increase in cost (β = 0.002, p=0.002). RoHI was evaluated in a subset analysis and was not independently associated with total DOS cost after adjustment. In anchor analysis (n = 105), RoHI ≥ 5 was associated with higher unadjusted implant cost, total DOS cost, and longer operative time (all p < 0.020). Conclusions In augmented RCR, fixation technique, operative duration, and institution were each independently associated with DOS cost variation; among these, implant selection is the most readily modifiable driver. Augmentation was more frequently utilized in higher-risk tears, although this difference did not reach statistical significance, and higher RoHI scores were associated with greater unadjusted intraoperative resource utilization. These findings provide a risk-adjusted framework for understanding intraoperative cost structure in augmented repair.