Performance of 5-Strand Hamstring Autograft Anterior Cruciate Ligament Reconstruction in the STABILITY Study: A Subgroup Analysis

Abstract

Background: Anterior cruciate ligament (ACL) reconstructions (ACLRs) with graft diameters <8mm have been shown to have higher revision rates. The 5-strand (5S) hamstring autograft configuration is a proposed option to increase graft diameter. Purpose: To investigate the differences in clinical outcomes between 4-strand (4S) and 5S hamstring autografts for ACLR in patients who underwent ACLR alone or concomitantly with a lateral extra-articular tenodesis (LET) procedure. Study Design: Cohort study; Level of evidence, 2. Methods: Data from the STABILITY study were analyzed to compare a subgroup of patients undergoing ACLR alone or with a concomitant LET procedure (ACLR + LET) with a minimum graft diameter of 8mm that had either a 4S or 5S hamstring autograft configuration. The primary outcome was clinical failure, a composite of rotatory laxity and/or graft failure. The secondary outcome measures consisted of 2 patient-reported outcome scores (PROs)—namely, the ACL Quality of Life Questionnaire (ACL-QoL) and the International Knee Documentation Committee (IKDC) score at 24 months postoperatively. Results: Of the 618 patients randomized in the STABILITY study, 399 (228 male; 57%) fit the inclusion criteria for this study. Of these, 191 and 208 patients underwent 4S and 5S configurations of hamstring ACLR, respectively, with a minimum graft diameter of 8mm. Both groups had similar characteristics other than differences in anthropometric factors—namely, sex, height, and weight, and Beighton scores. The primary outcomes revealed no difference between the 2 groups in rotatory stability (odds ratio [OR], 1.19; 95% CI, 0.77-1.84; P = .42) or graft failure (OR, 1.13; 95% CI, 0.51-2.50; P = .76). There was no significant difference between the groups in Lachman ( P = .46) and pivot-shift ( P = .53) test results at 24 months postoperatively. The secondary outcomes revealed no differences in the ACL-QoL ( P = .67) and IKDC ( P = .83) scores between the 2 subgroups. Conclusion: At the 24-month follow-up, there were no significant differences in clinical failure rates and PROs in an analysis of patients with 4S and 5S hamstring autografts of ≥8mm diameter for ACLR or ACLR + LET. The 5S hamstring graft configuration is a viable option to produce larger-diameter ACL grafts.

Though five‐strand hamstring autografts demonstrate greater graft diameter, postoperative outcomes are equivocal to four‐strand hamstring autograft preparations: a systematic review and meta‐analysis of level I and II studies

“…Two studies comprising 236 and 229 patients in the iveand four-strand groups, respectively, reported on postoperative IKDC scores [19,23] (Table 3). The follow-up time in both groups was 24 months.…”

“…One study rated a positive Lachman test according to the IKDC form as 1 (< 5 mm anterior translation of the tibia), 2 (5-10 mm), and 3 (> 10 mm) [19]. Another study rated a positive Lachman test as class B-D with unspeciied translation values [23]. Positive pivot shift was rated as mild asymmetric or glide (grade 1), moderate or clunk (grade 2), and severe or gross (grade 3) [19,23].…”

“…Another study rated a positive Lachman test as class B-D with unspeciied translation values [23]. Positive pivot shift was rated as mild asymmetric or glide (grade 1), moderate or clunk (grade 2), and severe or gross (grade 3) [19,23]. The average follow-up…”

“…Two studies comprising 236 and 229 patients in the ive-and four-strand groups, respectively, reported on positive Lachman and pivot shift tests postoperatively [19,23] (Table 4). One study rated a positive Lachman test according to the IKDC form as 1 (< 5 mm anterior translation of the tibia), 2 (5-10 mm), and 3 (> 10 mm) [19].…”

“…Allograft augmentation has been investigated; however, allografts have been shown to be associated with worse subjective knee outcomes, increased instability, and greater cost [6,26]. Recent literature has investigated using a ive-strand hamstring autograft in the skeletally mature population by using three semitendinosus loops as opposed to the standard two semitendinosus loops found in traditional four-strand autografts for patients with graft diameters below 8 mm [16,19,20,23,35]. While it is important to consider that success post-ACLR is dependent on a variety of factors, ive-strand grafts potentially could provide surgeons with a convenient option for this patient population if graft diameters are consistently above 8 mm with improved clinical outcomes.…”