Background: Anterior cruciate ligament (ACL) injuries in skeletally immature athletes are increasing. Purpose: To evaluate the 2-year clinical outcomes of all-inside, all-epiphyseal ACL reconstruction in skeletally immature athletes with 3 to 6 years of remaining growth, with a focus on return to sport and the incidence of second surgery. Study Design: Case series; Level of evidence, 4. Methods: Twenty-three skeletally immature athletes were prospectively evaluated after all-epiphyseal ACL reconstruction utilizing a hamstring autograft. The athletes' age, sex, sport, mechanism of injury, radiographs, and magnetic resonance imaging (MRI) findings were noted. The evaluation included a physical examination, KT-1000 arthrometer measurements, isokinetic testing, and validated outcome scores. Standing radiographs and spoiled gradient recalled echo MRI scans were obtained at 6, 12, and 24 months postoperatively. A quality of movement assessment and return-to-sport performance analysis were also performed. Results: Of the 23 athletes, 6 were female (mean age, 11.3 years), and 17 were male (mean age, 12.6 years). At a minimum follow-up of 2 years (range, 24-45 months), the mean International Knee Documentation Committee score was 94.6 4.9, the mean Lysholm score was 97.9 +/- 4.0, the mean Marx activity rating scale score was 13.4 +/- 3.6, and the mean Hospital for Special Surgery Pediatric Functional Activity Brief Scale score was 23.9 +/- 7.0. Lachman and pivot-shift test results were negative in all patients. The mean side-to-side difference on the KT-1000 arthrometer was 0.9 +/- 0.5 mm and less tight on the operated side. No significant growth disturbances were noted; however, 6 athletes had a leg-length discrepancy of more than 5 mm (range, 6-18 mm). Two patients had overgrowth in the femur of more than 15 mm (16 mm and 18 mm). Two athletes (8.7%) required second surgery. The mean time to return to unrestricted activity was 13.5 months (range, 8-22 months). Conclusion: The all-inside, all-epiphyseal ACL reconstruction technique using a hamstring autograft demonstrates excellent subjective and objective clinical outcomes in skeletally immature athletes without physeal arrest.
