Higher Physiologic Platelet Counts in Whole Blood Are Not Associated With Improved ACL Cross-sectional Area or Signal Intensity 6 Months After Bridge-Enhanced ACL Repair.

BACKGROUND

A bridge-enhanced anterior cruciate ligament (ACL) repair (BEAR) procedure places an extracellular matrix implant, combined with autologous whole blood, in the gap between the torn ends of the ligament at the time of suture repair to stimulate healing. Prior studies have suggested that white blood cell (WBC) and platelet concentrations significantly affect the healing of other musculoskeletal tissues.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine whether concentrations of various blood cell types placed into a bridging extracellular matrix implant at the time of ACL repair would have a significant effect on the healing ligament cross-sectional area or tissue organization (as measured by signal intensity). We hypothesized that patients with higher physiologic platelet and lower WBC counts would have improved healing of the ACL on magnetic resonance imaging (MRI) (higher cross-sectional area and/or lower signal intensity) 6 months after surgery.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 61 patients underwent MRI at 6 months after bridge-enhanced ACL repair as part of the BEAR II trial. The normalized signal intensity and average cross-sectional area of the healing ligament were measured from a magnetic resonance stack obtained using a gradient echo sequence. The results were stratified by sex, and univariate and multivariate regression analyses determined significant correlations between blood cell concentrations on these 2 magnetic resonance parameters.

RESULTS

In unadjusted analyses, older age and male sex were associated with greater healing ligament cross-sectional area (

CONCLUSION

Although older age, male sex, and monocyte concentration in female patients were associated with greater healing ligament cross-sectional area, signal intensity of the healing ligament was independent of these factors. Physiologic platelet concentration did not have any significant effect on cross-sectional area or signal intensity of the healing ACL at 6 months after bridge-enhanced ACL repair in this cohort. Given these findings, factors other than the physiologic platelet concentration and total WBC concentration may be more important in the rate and amount of ACL healing after bridge-enhanced ACL repair.

Informations de copyright

© The Author(s) 2020.

Déclaration de conflit d'intérêts

One or more of the authors has declared the following potential conflict of interest or source of funding: Funding was received from the Translational Research Program at Boston Children’s Hospital, the Children’s Hospital Orthopaedic Surgery Foundation, the Children’s Hospital Sports Medicine Foundation, and the National Institutes of Health and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (grants R01-AR065462 and R01-AR056834). This research was also conducted with support from the Football Players Health Study at Harvard University. The Football Players Health Study is funded by a grant from the National Football League Players Association. The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of Harvard Medical School, Harvard University or its affiliated academic health care centers, the National Football League Players Association, Boston Children’s Hospital, or the National Institutes of Health. M.M.M. and Boston Children’s Hospital have equity interests in MIACH Orthopaedics, a company that has licensed the BEAR scaffolding technology from Boston Children’s Hospital. M.M.M. has also received honoraria from the Musculoskeletal Transplant Foundation and royalties from Springer Publishing. B.C.F. has received educational support from Smith & Nephew, consulting fees from the New York R&D Center for Translational Medicine and Therapeutics, and royalties from Springer and is a paid associate editor for The American Journal of Sports Medicine. D.E.K. has received educational support from Kairos Surgical. B.L.P. has equity interests in and is a consultant for MIACH Orthopedics. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.