Does fat infiltration of the rotator cuff muscles contribute to 8increased hidden blood loss (HBL) and other risk factors during arthroscopic rotator cuff repair for rotator cuff injuries?

Abstract Objective To compare hidden blood loss (HBL) among patients with rotator cuff injuries undergoing arthroscopic rotator cuff repair who exhibit varying degrees of fatty infiltration in the rotator cuff muscles, and to investigate whether the extent of fatty infiltration in these muscles is associated with increased HBL and other risk factors. Methods A retrospective analysis was performed on data from 141 patients with rotator cuff injuries who underwent arthroscopic rotator cuff repair between January 2023 and March 2025. Patients were categorized into grades 0 to 4 according to the severity of fatty infiltration in the rotator cuff muscles. Demographic characteristics and blood-related parameters were collected for each group. Visible blood loss was quantified, and hidden blood loss (HBL) was calculated using preoperative hematocrit (Hctpre) and postoperative hematocrit (Hctpost) to assess total blood loss.Pearson or Spearman correlation analyses were conducted to evaluate the relationship between patient characteristics and HBL. Multivariate linear regression analysis was performed to determine the independent risk factors associated with HBL. Results Multivariate linear regression analysis revealed that postoperative hematocrit (Hctpost), intraoperative blood loss, classification of fatty infiltration in the rotator cuff muscles, and grading of rotator cuff tear size were independent risk factors for hidden blood loss (HBL) in patients. Conclusion Patients exhibiting higher degrees of fatty infiltration in the rotator cuff muscles, as well as those with more extensive rotator cuff tears, may be associated with increased levels of hidden blood loss (HBL) during arthroscopic rotator cuff repair. Factors such as postoperative hematocrit (Hctpost), intraoperative bleeding volume, severity of fatty infiltration, and tear size have been suggested as potential independent risk factors for HBL. Close perioperative monitoring of these parameters could contribute to improved patient safety during arthroscopic rotator cuff repair procedures.