Bone Tunnel Microarchitecture and Early Functional Recovery After Anterior Cruciate Ligament Reconstruction: A Prospective HR-pQCT Cohort Study

BACKGROUND: The biological healing of the bone tunnel is crucial for success in anterior cruciate ligament reconstruction (ACLR). Nonetheless, conventional imaging cannot assess the key microarchitectural properties of the healing bone, resulting in a gap in our understanding of early recovery. PURPOSE/HYPOTHESIS: This study aimed to identify the specific bone structure and density measurements most closely associated with successful recovery during the first 6 months. It was hypothesized that the microarchitectural properties of the bone tunnel, quantified by high-resolution peripheral quantitative computed tomography (HR-pQCT), would be directly correlated with functional and patient-reported outcomes in the early postoperative phase. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: In a prospective cohort study, 50 patients undergoing primary hamstring ACLR were assessed at 4 and 6 months postoperatively. HR-pQCT was used to quantify bone tunnel parameters-including bone volume/total volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and tunnel enlargement ratio. The isokinetic muscle strength test, single-leg hop test, ultrasound muscle thickness assessment, and patient-reported outcomes were assessed for clinical performance. The Spearman correlation was used to examine the relationship between knee joint clinical performance and bone tunnel conditions. Receiver operating characteristic (ROC) analysis was performed to identify predictive thresholds for good functional recovery. RESULTS: = .027), with an optimal cutoff value of 0.2607. CONCLUSION: The microarchitectural quality of the bone tunnel, as assessed by HR-pQCT, is modestly correlated with the early functional recovery after ACLR, particularly at the 4-month postoperative time period.