NON-SURGICAL MANAGEMENT OF NEAR FULL-THICKNESS ACL TEAR WITH CROSS BRACING AND PLATELET RICH PLASMA: A CASE STUDY

Abstract

Background: Anterior cruciate ligament (ACL) ruptures in young athletes are commonly managed surgically due to concerns about instability and low return-to-sport rates with conservative care (1). However, surgery entails lengthy rehabilitation and risk of complications (donor site morbidity, osteoarthritis)(1), spurring interest in novel non-operative treatments. Recent evidence suggests some ACL tears can heal with appropriate bracing(2). Platelet-rich plasma (PRP) injections may biologically augment healing by delivering growth factors to injured tissue(1). We report a case of a near full-thickness ACL tear with meniscal injury in a competitive athlete, treated non-operatively with a structured bracing protocol and PRP injection.

Case Presentation: A 24-year-old male state-level badminton player sustained an  left knee ACL injury (near full-thickness tear of the anteromedial bundle) and a posterior horn of lateral meniscus tear during landing from a jump. He presented with acute knee pain and swelling, medial joint-line tenderness, and positive McMurray and Thessaly tests indicating lateral meniscal involvement. Lachman test demonstrated grade 2A anterior laxity (moderate translation with a firm endpoint), consistent with a substantial ACL tear. Despite the high-grade lesion, the patient was keen to avoid surgery and attempt accelerated conservative management.

Intervention: Within one week of injury, the patient received an intra-articular injection of 4 mL leukocyte-rich PRP under sterile conditions. One-week post-injury, he commenced a supervised 12-week Cross Bracing Protocol (CBP). This protocol entailed immediate knee immobilisation at 90° flexion for 4 weeks, followed by gradual brace unlocking over 5–8 weeks to increase range-of-motion, with full weight-bearing allowed as the range increased(2). The brace was removed at 12 weeks post-injury, coinciding with an MRI and clinical evaluation (per CBP guidelines)(2). During bracing, structured rehabilitation focused on quadriceps isometrics, hamstring co-contractions, and protected weight-bearing exercises; after brace removal, progressive strength training, neuromuscular control, balance, plyometrics, and sport-specific drills were introduced up to 16 weeks.

Outcomes: Pain, function, psychological readiness, and stability were assessed at baseline, 6 weeks, and 12 weeks. The Visual Analog Scale (VAS) for pain improved from 6/10 at baseline to 1/10 at 12 weeks. The ACL–Return to Sport after Injury (ACL-RSI) psychological readiness score improved from 42 to 79 (on 0–100 scale). Single leg hop distance (injured side) increased from 0 (unable to hop at baseline) to 140 cm at 12 weeks, reaching 90% of the contralateral leg distance. Thigh muscle girth deficit (injured vs. uninjured) reduced from 2.0 cm to 0.6 cm. Notably, clinical knee stability improved: Lachman test downgraded from grade 2A to grade 1 (near-normal endpoint) and pivot-based tests for meniscus became negative. The athlete resumed controlled sports training by 16 weeks and was preparing for return to competitive play. No adverse events (e.g. deep vein thrombosis or significant swelling) occurred.

Conclusion: In this case, a near full-thickness ACL tear with a posterior horn of lateral meniscus tear healed sufficiently to restore knee stability and function without surgery. A combination of early PRP injection and the Cross Bracing Protocol yielded rapid pain relief, ligament continuity (clinically), and a return towards high-level sport in 4 months. This case aligns with emerging evidence that certain ACL ruptures may heal with timely bracing and biological augmentation(1,3). While surgical reconstruction remains standard for young athletes, this report highlights a non-operative approach that avoided surgery and its sequelae. Further research (including randomized trials) is needed to identify ideal candidates and confirm long-term outcomes of ligament-healing treatments.