[Augmentation of the Anterior Cruciate Ligament in Patients with Symptomatic Isolated Tear of Anteromedial or Posterolateral Bundle: Evaluation of Two-Year Clinical Results].

PURPOSE OF THE STUDY: We present the results of a prospective study of patients with symptomatic partial ACL tears comparing the pre-operative findings with the clinical results at two years after anterior cruciate ligament (ACL) augmentation.

MATERIAL AND METHODS: A total of 29 patients (7 women, 22 men; average age, 27.8 years) who were diagnosed with an isolated tear of the posterolateral (PL) bundle (18 patients) or the anteromedial (AM) bundle (11 patients) at 9 to 24 weeks after injury, and underwent ACL augmentation by isolated PL or AM bundle replacement, were evaluated. The characteristics assessed before surgery and at two years after it included the Lysholm and subjective IKDC scores and knee laxity measurement with a GNRB arthrometer (at 134 N and 250 N) and its assessment by the Lachman, anterior drawer and pivot shift tests. In addition, the presence of cyclop syndrome, graft failure and post-operative complications were evaluated.

RESULTS: The patients with isolated reconstruction of the PL bundle showed post-operatively statistically significant improvement in the degree of rotational knee laxity (p < 0.05) and the ventral knee laxity assessed by the Lachman test (p < 0.05). Postoperative improvement in the anterior drawer test results was not statistically significant (p = 0.07). The median value of side-to-side difference in knee laxity measured with the GNRB arthrometer decreased at 134 N from 1.7 mm pre-operatively to 0.8 mm at two years post-operatively (p < 0.05) and, at 250 N, from 2.8 mm to 1.5 mm (p < 0.05). The median Lysholm score increased from 74 to 91 points at two post-operative years and the median IKDC score improved from 76 to 92 points (p < 0.05). Graft failure was reported in one patient (5.6%) and 14 subjects (77.8%) reported return to pre-injury sports activities. The patients undergoing isolated reconstruction of the AM bundle achieved, at two years after surgery, a statistically significant decrease in positivity of the Lachman and anterior drawer tests (p < 0.05), while the results of the pivot shift test did not improve significantly (p = 0.09). The decrease in median values of side-to-side difference in knee laxity measured with the GNRB arthrometer was from pre-operative 3.1 mm to 1.2 mm at 134 N (p < 0.05) and from 6.2 mm to 1.9 mm at 250N (p < 0.05). The median Lysholm and IKDC scores increased from 68 to 92 points and from 70 to 94 points, respectively (p < 0.05). Nine patients (81.9%) reported return to pre-injury participation in sports. Apart from early wound bleeding in one patient, no complications were recorded.

DISCUSSION: By permitting maintenance of a healthy bundle and replacement of only a torn one, ACL augmentation provides several benefits. It allows for accelerated revascularization and re-innervation of the graft through mechanoreceptors of the healthy portion; it enables the surgeon to get a good anatomical orientation and achieve precise tunnel reaming; in addition the healthy bundle provides protection for the graft in the early post-operative period. Thus rehabilitation can be faster and also return to sports activities.

CONCLUSIONS: Our results show that ACL augmentation using isolated replacement of either the AM or the PL bundle brings about statistically significant improvement of all subjective and most of the objective criteria by two years after surgery.