ACL reconstruction using 5- or 6-strand hamstring autograft provides graft’s diameter bigger than 8 mm

Background: Anterior cruciate ligament reconstruction (ACLR) with hamstring autograft has gained popularity. However, an unpredictably small graft diameter has been a drawback of this technique. Smaller graft diameter has been associated with increased risk of revision, and increasing the number of strands has been reported as a successful technique to increase the graft diameter. Purpose: To compare failure rates of 5-strand (5HS) and 6-strand (6HS) hamstring autograft compared with conventional 4-strand (4HS) hamstring autograft. We describe the technique in detail, supplemented by photographs and illustrations, to provide a reproducible technique to avoid the variable and often insufficient 4HS graft diameter reported in the literature. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively reviewed prospectively collected data of all primary hamstring autograft ACLRs performed at our institution with a minimum 2-year follow-up and 8.0-mm graft diameter. A total of 413 consecutive knees met the study inclusion and exclusion criteria. The study population was divided into 5HS and 6HS groups as well as a 4HS control group. The primary outcome was failure of ACLR, defined as persistent or recurrent instability and/or revision ACLR. Results: The analysis included 224, 156, and 33 knees in the 5HS, 6HS, and 4HS groups, respectively. The overall ACLR failure rate in this study was 11 cases (8%): 5 cases for 5HS, 3 cases for 6HS, and 3 cases for 4HS. No statistically significant differences were found among groups ( P = .06). The mean graft diameter was 9 mm, and the mean follow-up was 44.27 months. Conclusion: The 5HS and 6HS constructs have similar failure rates to the conventional 4HS construct of 8.0-mm diameter and are therefore safe and reliable to increase the diameter of relatively smaller hamstring autografts. We strongly recommend using this technique when the length of the tendons permits to avoid failures reportedly associated with inadequate graft size.

Section: Discussionsupporting

confidence: 91%

“…11,22 A 6-strand configuration (6HS) has also been described. In a series published by Tutkus et al, 25 the 5- and 6-strand configurations had a probability of almost 100% of producing grafts of more than 8.0 mm in diameter.…”

mentioning

confidence: 95%

Failure Rates of 5-Strand and 6-Strand vs Quadrupled Hamstring Autograft ACL Reconstruction: A Comparative Study of 413 Patients With a Minimum 2-Year Follow-up

Attia

Nasef

ElSweify

et al. 2020

“…The remaining 1.6% of 5HS grafts less than 8 mm in diameter all occurred within female cases. 32 However, results of the current systematic review indicate no significant differences in clinical outcomes between 5HS autografts and 4HS autografts that are already greater than 8 mm in diameter. Calvo et al 6 reported that there was no statistically significant difference in rerupture rates between 4HS grafts greater than 8 mm in diameter and 5HS grafts.…”

Section: Discussionmentioning

confidence: 57%

“…6,18,19 It has been noted that the 5HS graft technique does increase the graft diameter and therefore has the potential to increase the overall success in grafts that would otherwise be less than 8 mm in diameter. Tutkus et al 32 suggested that 5HS grafts have a diameter that is significantly larger than 8 mm in 98.4% of cases. The remaining 1.6% of 5HS grafts less than 8 mm in diameter all occurred within female cases.…”

Section: Discussionmentioning

confidence: 99%

Five-Strand Hamstring Autografts for Anterior Cruciate Ligament Reconstruction: A Systematic Review

Smith

Houck

Hart

et al. 2019

Background: Recent studies have described surgical techniques to increase the hamstring graft diameter for anterior cruciate ligament reconstruction (ACLR), particularly for 5-strand hamstring (5HS) autografts. Purpose: To review the literature examining the biomechanical and clinical outcomes of 5HS autografts for ACLR. Study Design: Systematic review; Level of evidence, 3. Methods: A systematic review using PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines was performed by searching PubMed, Embase, and the Cochrane Library for studies reporting the biomechanical and clinical outcomes of 5HS autografts. All English-language literature published from 2012 to 2018 that reported the biomechanical properties of 5HS grafts and/or clinical outcomes after ACLR with 5HS autografts with a minimum 1-year follow-up was reviewed by 2 independent reviewers. Graft diameter, stiffness, displacement, strength, failure rates, anteroposterior knee laxity, and patient-reported outcome scores were collected. The study methodology was evaluated using the modified Coleman Methodology Score. Results: Two biomechanical and 3 clinical studies (1 with level 2 evidence, 2 with level 3 evidence) were included. The biomechanical studies compared the results of fourteen 4-strand hamstring (4HS) and fourteen 5HS graft specimens for ACLR (ovine grafts, n = 12; cadaveric grafts, n = 16) and found no significant differences in ultimate load, stiffness, displacement, and stress relaxation ( P > .05), likely attributed to insufficient incorporation of the fifth strand. The mean 5HS cadaveric graft diameter (8.2 mm) was significantly greater than that of 4HS grafts (6.8 mm) ( P = .002), whereas the mean ovine graft diameters were not significantly different (4HS, 5.2 mm; 5HS, 5.3 mm) ( P > .05). Two clinical studies compared the outcomes after ACLR of 53 patients with a 4HS autograft versus 62 patients with a 5HS autograft, while 1 clinical study reported the outcomes of 25 patients after ACLR with a 5HS autograft (mean age, 28.7 years; mean follow-up, 24.8 months). The overall mean diameter for 4HS and 5HS autografts was 8.4 and 9.1 mm, respectively. There was no significant difference in failure rates between 4HS and 5HS autografts ( P = .82). None of the comparative studies reported significant differences in any clinical outcomes ( P > .05 for all). Conclusion: The available literature on traditional 4HS and 5HS autografts for ACLR is limited. Of the available data, clinical and biomechanical studies suggest no difference in outcomes after ACLR with either graft construct. Additional research is needed to determine whether creating a 5HS graft is beneficial.

“…11,19 Grafts with smaller diameters are more susceptible to rerupture. 3,5,27 However, grafts should also be evaluated from a biological perspective. Several techniques for the preservation of the tibial stump of the anterior cruciate ligament (ACL) or an ACL repair are biological strategies to be considered for the religamentization process.…”

mentioning

confidence: 99%

Remnant Muscle Preservation on Hamstring Tendon Autograft During ACL Reconstruction Promotes Volumetric Increase With Biological and Regenerative Potential

Funchal¹,

Ortiz²,

Jimenez

et al. 2021

Background: The removal of all adherent muscle tissue from the hamstring graft during anterior cruciate ligament reconstruction (ACLR) is common practice. However, there is a paucity of research to justify this removal or evaluate its biological implications. Purpose/Hypothesis: The purpose of this study was to (1) evaluate the histological characteristics of the myotendinous muscle tissue harvested from hamstring tendons, (2) compare the final diameter of the prepared graft before and after the removal of the remnant musculature, and (3) evaluate patients who were treated with and without preservation of the graft-adhered muscle. The hypothesis was that the adherent musculature of the graft would have cells that could contribute to graft incorporation and revascularization, assist in the proprioceptive capacity of the neoligament, and increase the graft’s diameter. Study Design: Cohort study; Level of evidence, 3. Methods: We divided 84 patients into 2 groups: group 1 underwent ACLR using hamstring tendon autograft with adherent musculature, and group 2 underwent ACLR using hamstring tendon autograft stripped of its remnant muscle. All patients had minimum 2-year follow-up. The muscle harvested from the graft in group 2 was submitted for histological examination, and the graft diameter before and after muscle removal was compared. The Tegner activity scale and Lysholm scores were determined preoperatively and at 12 and 24 months postoperatively. Results: There was a significant difference in graft diameter between groups. The evaluation of the graft diameter in group 2 showed a decrease of 11.52% after removal of muscle tissue from the tendon graft. Patients from group 1 had better Tegner and Lysholm scores (mean ± SD) after 12 months (Tegner, 8.03 vs 7 [ P = .004]; Lysholm, 95.48 ± 1.2 vs 87.54 ± 3.21 [ P = .002]) and better Lysholm scores after 24 months (95.76 ± 2.1 vs 89.32 ± 2.47; P = .002). The muscle tissue of the analyzed fragments presented a pattern with fibrous tissue beams, invaginating regularly and sequentially from the myotendinous junction into the muscles. Conclusion: Preserving the muscle tissue on tendon grafts promoted a volumetric increase in the final autograft diameter and demonstrated biological and regenerative potential. Patients who underwent ACLR using the tendon with the muscle attached had better functional scores at 2-year follow-up as compared with patients treated using the tendon with the muscle removed.