The relationship between the clinical results and the remnant type following anterior cruciate ligament reconstruction using a hamstring tendon

Purpose: The aim of the present study was to investigate the correlations among the preoperative and postoperative knee laxity, the clinical results, and the type of remnant tissue following the anterior cruciate ligament (ACL) reconstruction. Methods: One hundred ninety-two patients (male, n = 101; female, n = 91; mean age, 27.1 years) with ACL-deficient knees who had undergone double-bundle reconstruction were included. The time between injury and surgery (TBIS) was 34.7 weeks (range, 1–504 weeks). The subjects were divided into four groups according to the Crain’s classifications and factors such as the age at surgery, gender, TBIS, side-to-side difference (SSD), Tegner activity score (TAS), and Lysholm score were compared. Results: The percentage of patients with ACL remnant pattern types 1, 2, 3, 4 was 19% (37 knees), 52% (101 knees), 9% (19 knees), and 18% (35 knees), respectively. The TBIS of the patients with Crain type 4 was significantly longer in comparison to the other groups (p < 0.01). A significant difference was observed in the preoperative SSD of the Crain type 3 and Crain type 4 (6.2 ± 3.4 mm, 9.3 ± 3.6, respectively) groups. The TBIS in patients with Crain type 4 was significantly longer in comparison to the other groups (p < 0.01). There were no significant differences between the groups in terms of the postoperative SSD, TAS, or Lysholm score. Conclusion: This study suggests that a Crain type 3 remnant was associated with a significantly lower preoperative SSD. In addition, the TBIS in patients with Crain type 4 was found to be significantly longer in comparison to the other groups. Level of Evidence: Level III, case–control study.