Effect of Hyperbaric Oxygen Therapy on Early MRI-Based Graft Healing Following ACL Reconstruction With Hamstring Autografts

Background: Anterior cruciate ligament reconstruction (ACLR) requires optimal graft healing for successful outcomes. Magnetic resonance imaging (MRI) is widely used to monitor graft maturation, with lower graft signal intensity suggesting better tissue organization and advanced healing. Hyperbaric oxygen therapy (HBOT) has shown promise in enhancing healing, but its effect on anterior cruciate ligament graft maturation in humans remains unclear. Purpose: To evaluate the impact of adjuvant HBOT on graft maturation and integration in patients undergoing ACLR, using 4-month postoperative MRI. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent primary anatomic ACLR with hamstring autografts and adjuvant HBOT were identified and matched 1:1 by sex and age (55 years) with controls who did not receive HBOT. MRI was performed at 4 months postoperatively. Graft signal-to-noise quotient (SNQ) was measured to quantify graft maturation and analyzed using the Mann-Whitney U test; bone marrow edema at the graft-bone tunnel interface (graded as absent, mild, or accentuated) was used to infer graft integration and analyzed using the Fisher exact test. Results: In total, 52 patients (26 HBOT, 26 controls; mean age 37.0 ± 13.5 years; 61.5% male) were included. Patients receiving HBOT exhibited significantly lower graft SNQ compared to controls (median difference, 83.9; P = .031), indicating improved graft maturation. Bone marrow edema at the graft-bone tunnel interface was also lower in the HBOT group ( P = .029), suggesting enhanced graft integration. Conclusion: In this pilot study, adjuvant HBOT following ACLR was associated with significantly improved signs of graft maturation and integration, as evidenced by lower graft signal intensity and interface signal on MRI at 4 months, suggesting accelerated early healing. These findings may help refine strategies to enhance early graft incorporation and support the development of rehabilitation protocols that optimize postoperative outcomes for patients undergoing ACLR.