Clinical Outcomes of Single Anteromedial Bundle Biologic Augmentation Technique for Anterior Cruciate Ligament Reconstruction With Consideration of Tibial Remnant Size

PURPOSE: The primary aim of this study was to evaluate the functional outcomes, knee stability, complications, and reoperations associated with anatomic anterior cruciate ligament (ACL) reconstruction using the single anteromedial bundle biological augmentation (SAMBBA) technique in a consecutive series of 128 patients with a minimum follow-up of 24 months. A secondary aim was to compare larger preserved ACL remnants with smaller preserved remnants.

METHODS: Patients who underwent primary anatomic ACL reconstruction using the SAMBBA technique from July 2013 to October 2014 were analyzed. Exclusion criteria were (1) age <16 years, (2) revision cases, (3) multiple ligament injuries, (4) chondral lesions greater than grade 2 according to the Outerbridge classification, (5) additional injuries to the collateral ligaments greater than grade 2, or (6) a history of a contralateral ACL injury. Clinical assessment including evaluation of side-to-side difference and functional outcome measures with the International Knee Documentation Committee (IKDC) subjective score and the Tegner Activity Scale were used to evaluate outcomes before surgery and at the last follow-up. Any subsequent surgical procedures were systematically recorded during the study period. The patients were also divided in 2 groups according to their ACL remnant size, ≥50% or <50%, and compared.

RESULTS: Of the 135 patients who underwent primary SAMBBA technique, 128 patients returned to final follow-up, with a mean follow-up of 31.7 months (range, 24-44.3). At last follow-up, the IKDC score significantly improved from 54.1 ± 15.1 to 92.5 ± 11.4 (P < .001); the Tegner activity score (6.4 ± 1.2) was similar (P = .3) to the preinjury score (6.5 ± 1.2). Side-to-side laxity significantly improved from 6.7 ± 1.2 mm to 0.7 ± 1 mm (P < .001). Twenty-four subsequent surgeries (18.7%) were performed including 10 meniscal procedures, 7 ACL revisions, 5 arthroscopies for cyclops lesions, one microfracture, and one manipulation under anaesthesia. The side-to-side laxity (P = .30) and rates of reoperation (P = .65), graft failure (P = .45), and cyclops lesions (P = .67) were not significantly different between ≥50% or <50% ACL remnant groups.

CONCLUSIONS: The results of this study demonstrate that primary anatomic ACL reconstruction using the SAMBBA technique significantly improved clinical and functional outcomes between baseline and follow-up at a minimum of 24 months. A low rate of complications was observed with this technique. No significant differences between large and moderate size ACL remnants were detected for all outcome measures.

LEVEL OF EVIDENCE: Level IV case series with subgroup analysis.