Synovialization on second-look arthroscopy after anterior cruciate ligament reconstruction using Achilles allograft in active young men

Purpose: This study is to assess the relationship between clinical outcomes and the extent of synovialization through second-look arthroscopy for anterior cruciate ligament (ACL) reconstruction using Achilles allograft in active young men. Methods: Ninety-five subjects were diagnosed with ACL rupture and underwent reconstruction with Achilles allograft. Median age was 22 years old (range, 17-40). Mean period from injury to operation was 15.1 ± 18.2 weeks. Lysholm score, IKDC classification, range of motion (ROM) of knee, and side-to-side difference (SSD) in anterior instability were evaluated preoperatively and at the last follow-up. Tegner activity scale was evaluated before injury and at the final follow-up. The extent of synovialization of the graft was evaluated under second-look arthroscopy at least 1 year after surgery. Formation of the synovial membrane was divided into four groups-group 1 for 25% or less, group 2 for 25-50%, group 3 for 50-75%, and group 4 for more than 75%. Outcomes were compared between each group. Results: Lysholm score and IKDC classification were improved after surgery (P < 0. 05). Most subjects had full ROM at the final follow-up except three subjects that showed flexion deficit of 5 degrees or less. Mean SSD in anterior instability was 9.0 ± 2.1 mm preoperatively and 1.6 ± 2.0 mm at the final follow-up (P < 0.001). Median Tegner activity scale was 7 before injury and 7 at the final follow-up (P < 0.001). Twelve subjects were in group 1, 10 in group 2, 14 in group 3, and 59 in group 4. Clinical outcomes depending on the extent of synovialization of the grafts were different between each group (P < 0.05). The average period from injury to reconstruction in each group was significantly different (P < 0.001). Correlation coefficient between the period from injury to reconstruction and the extent of synovialization was -0. 411 (P < 0.001). Conclusion: The extent of the synovialization is positively correlated with clinical outcomes and is negatively correlated with the period from injury to reconstruction. Level of evidence: Therapeutic study-investigating the results of treatment, Level III.