Acute Primary Anterior Cruciate Ligament Repair for Sherman Type I and II Tears Shows Significantly Improved Clinical Outcome and Ligamentous Maturation by Serial Magnetic Resonance Imaging Analysis.

Purpose: To analyze the clinical and radiographic outcomes of patients who underwent anterior cruciate ligament (ACL) primary repair within 15 days of the index injury.

Methods: All patients undergoing acute (within 15 days of the injury) ACL primary repair between January 2019 and June 2020 were eligible. Inclusion criteria were ACL injuries classified as Sherman I and II (proximal tears) and as Marshall grades A and B (good and moderate tissue quality). Patients underwent sequential magnetic resonance imaging (MRI) scanning at 1, 3, 6, and 12 months postoperatively. Patients had to have had at least 2 of the 4 scheduled MRIs to be included. The ligamentization process was evaluated using signal-to-noise quotient (SNQ) and Howell scale. SNQ was analyzed via repeated-measures analysis of variance with Bonferroni corrections for multiple comparisons, whereas the Howell scale progression was analyzed with a Friedman test and post hoc Wilcoxon tests. Clinical outcomes were recorded at the final follow-up, 24 months after surgery, using the following patient-reported outcome measures: Lysholm Knee Scoring Scale (LKSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Anterior Cruciate Ligament Return to Sport after Injury, the Forgotten Joint Score-12, Manual Maximum KT-1000, the International Knee Documentation Committee, and the Tegner Score.

Results: The study included 50 patients (mean age, 31.7 ± 12.7 years), 21 male (42%) and 29 female (58%). The mean time from injury to surgery was 9.2 ± 2.9 days. A total of 47 patients had MRI at 1 month after surgery (mean 30 days, range 28-32 days); 47 patients had MRI at 3 months after surgery (mean 91 days, range 88-95 days); 45 patients had MRI at 6 months after surgery (mean 181 days, range 178-184 days); and 49 patients had MRI at 12 months after surgery (mean 361 days, range 356-365 days). Mean SNQ and Howell scale scores showed a consistent decrease-representing an improved ligament maturation-over the 4 time points. Significant reductions of SNQ values occurred between 1 and 6 months (P < .001), 1 and 12 months (P < .001), 3 to 6 months (P < .001), and 3 to 12 months (P < .001). No significant difference was found between 1 and 3 months (P = .075) or 6 and 12 months (P = .436). The Howell scale scores showed a significant overall reduction over time (χ² [3] = 28.253; P < .001), with significant improvements occurring between 1 and 6 months (P < .001), 1 and 12 months (P < .001), 3 to 6 months (P = .005), and 3 to 12 months (P = .008). No significant difference was found between 1 and 3 months (P = .05) 6 and 12 months (P = .303). Clinical outcomes were recorded at 24 months after surgery (mean 1095 days, range 745-1486 days). The average Lysholm score was 84.73 ± 14.47 and the average KOOS score was 85.29 ± 13.97; 86.3% of patients achieved Patient Acceptable Symptom State for the KOOS subscales. A significant correlation between Howell grade and SNQ (r = 0.483, P < .001) was found, but not between Howell grade or SNQ and other functional outcome measures.

Conclusions: Patients who underwent acute primary ACL repair had good clinical outcomes on both patient-reported outcomes and Manual Maximum KT-1000 at a minimum 24 months of follow-up. A correlation was found between the signal on MRI and the healing phase. Continuous healing was observed during the first postoperative year, with consistent decreases in SNQ and Howell scale scores. In addition, patients had good clinical outcomes, as evidenced by high mean scores and percentage of patient-acceptable symptom state achievement on PROMs.

Level of evidence: Level IV, case series.