Application of internal brace ligament augmentation technique in knee ligament injury: a systematic review

BACKGROUND: Anterior cruciate ligament (ACL) injuries are common and can lead to significant knee instability and an increased risk of long-term cartilage damage. Given the emerging role of internal brace ligament augmentation (IBLA) in treating these injuries, this systematic review aimed to evaluate the collective evidence on the safety and effectiveness of IBLA in patients with anterior cruciate ligament injury. METHODS: We systematically searched the PubMed, Embase, Cochrane Library, and Web of Science databases until July 2025. The literature was screened according to the inclusion and exclusion criteria, and data were extracted. The extracted key data included the International Knee Documentation Committee score (IKDC), Tegner score, Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Arthritis Index score (WOMAC), Marx Activity Scale, visual analogue scale (VAS), and the Veterans RAND 12-Item Health Survey (VR-12). The quality of nonrandomized trials was assessed using the Newcastle-Ottawa Scale (NOS). RESULTS: Systematic screening identified 11 studies (n = 676 patients) for analysis. Patient-reported outcomes demonstrated significant improvements post-intervention. Meta-analyses demonstrated statistically significant increases in KOOS (MD = 36.86, 95% CI: 32.51-41.20, p < 0.01), VR-12 (MD = 16.62, 95% CI:14.75-18.49, p < 0.01), and decreases in visual analog scale (VAS) (MD = -2.82, 95% CI: -3.40 to -2.25, p < 0.01). Lysholm (postoperative 89-94) and IKDC scores (postoperative 85-91) approached or exceeded pre-injury levels. Tegner scores remained stable near pre-injury levels (5.33-6.4). Marx activity scores showed a significant decrease (MD = -3.84, 95% CI: -6.19 to -1.49, p < 0.01), potentially indicating postoperative activity adaptation. Study heterogeneity was noted. All included studies demonstrated mild to high quality. CONCLUSIONS: IBLA appears to be a promising technique for improving functionality, stability, and pain management in anterior cruciate ligament injury. However, the current evidence is significantly constrained by small sample sizes, a predominance of low-quality studies, and a lack of long-term comparative data. Therefore, further rigorous, high-quality research is required to definitively establish the safety and long-term effectiveness of IBLA. LEVEL OF EVIDENCE: III.