Risk of Secondary ACL Injury in Adolescents Prescribed Functional Bracing After ACL Reconstruction

Abstract

Background: There is a high incidence of a secondary anterior cruciate ligament (ACL) injury in unbraced adolescent athletes. Little is known about the effect of functional bracing with regard to the risk of secondary ACL injuries among adolescents.

Hypothesis: Our primary hypothesis was that adolescents would have a high rate of secondary ACL injury even with brace use. A secondary hypothesis was that the reinjury rate with brace use would be lower than that of a historical control group of unbraced patients.

Study design: Case series; Level of evidence, 4.

Methods: A group of 219 patients (age <20 years at surgery) who underwent ACL reconstruction and were prescribed postoperative functional bracing during cutting and pivoting sports for 2 years after surgery completed a survey regarding reinjury to either knee. Rates of knee injuries following ACL reconstruction were calculated and compared with those reported in a similar unbraced cohort. The effect of demographic and anatomic factors on risk of secondary ACL injuries was also investigated.

Results: The overall follow-up rate was 65% (142/219) at a mean 5.6 years after surgery. In the braced cohort, the overall graft retear rate was 10%, with the highest retear rates observed in male patients 17 years of age and younger (18%). The overall contralateral ACL injury and combined (graft or contralateral ACL) secondary injury rates were 13% and 23%, respectively, with female patients younger than 18 years having the highest contralateral and combined injury rates (17% and 26%, respectively). Younger age (odds ratio [OR], 0.70; P = .021), family history of ACL injury (OR, 2.81; P = .015), and higher lateral tibial slope (OR, 1.25; P = .016) were associated with increased risk of secondary knee injury in the braced cohort. Compared with the unbraced cohort, the braced cohort had a lower overall graft retear rate (P = .028), a lower graft retear rate in patients younger than 18 years (P = .012), lower early graft retear rate (within the first year after surgery) (P = .011), and lower early graft retear rate in subjects younger than 18 years (P = .003).

Conclusion: Postoperative use of functional bracing can result in reduced risk of graft retear and no change in contralateral injury rates. Clinicians may want to consider the use of postoperative functional bracing in adolescent patients.

Keywords: ACL reconstruction; functional bracing; graft injury.

Conflict of interest statement

One or more of the authors has declared the following potential conflict of interest or source of funding: Funding for this study was provided from the Children’s Hospital Orthopaedic Surgery Foundation and the Children’s Hospital Sports Medicine Foundation. 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. 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 received royalties from Springer Publishing; research support from the National Institutes of Health, Department of Defense, and National Football League Players Association through the Harvard Football Players Health Study; and honoraria from the Musculoskeletal Transplant Foundation. A.M.K. receives research support from the National Institutes of Health and National Football League Players Association through the Harvard Football Players Health Study. 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.

© The Author(s) 2019.

Figures

Figure 1.

Frequency distribution of bracing years (n = 135).

Figure 2.

Percentage of patients who sustained a graft rupture, contralateral ACL injury, and overall secondary ACL injury (ipsilateral or contralateral) per age group: 12-14 years (n = 28), 15-17 years (n = 87), and 18-19 years (n = 20). ACL, anterior cruciate ligament.

Figure A1.

Measurement techniques used to quantify notch width (NW), coronal tibial slope (CTS), medial tibial slope (MTS), medial tibial depth (MTD), and lateral tibial slope (LTS).