Hamstring Graft Preparation Techniques for Anterior Cruciate Ligament Reconstruction

Anterior Cruciate Ligament Reconstruction Utilizing Double Adjustable-Loop Suspensory Fixation Devices Provides Good Clinical Outcomes in Patients under the Age of 40 Years at Two-Year Follow-Up

Background: Anterior cruciate ligament reconstruction (ACLR) using double adjustable fixation gained popularity in the last decade due to its minimally invasive technique. However, suspensory fixation devices could be related to recurrent instability, poor clinical outcomes, and patient dissatisfaction. The present study aims to evaluate the clinical outcomes following ACLR using double adjustable-loop suspensory fixation devices in the demanding population of young patients. Methods: Between 2019 and 2022, 95 patients with knee post-traumatic anterior cruciate ligament insufficiency were treated with primary ACLR using semitendinosus quadrupled graft and double adjustable-loop suspensory fixation devices and followed for at least two years. Concomitant lesions were also treated at the same surgical time. The knee examination form of the International Knee Documentation Committee (IKDC) was used to assess clinical evaluation, and the return to physical activities using the Tegner Activity Scale was recorded. Patient-reported objective measures (PROMs) were also evaluated, including the IKDC subjective and Lysholm scores. Results: Sixty-six males and twenty-nine females with a mean age of 23.8 (range 18-37) and a mean BMI of 24.9 (SD ± 2.42) kg/m2 were included in this study. All patients were evaluated clinically as normal or nearly normal at the final follow-up. PROMs also significantly improved postoperatively (p < 0.05) compared to the preoperative values. The Tegner Activity Scale increased from 2 to 7, the IKDC mean score improved from 43.9 (±8.9) to 93.3 (±12.3), and the modified Lysholm from 47.3 (±11.1) to 92.9 (±16.6). No complications or adverse events were recorded. Conclusions: Anterior cruciate ligament reconstruction utilizing double adjustable-loop suspensory fixation devices provides good clinical and functional outcomes in young patients at a two-year follow-up.

Postoperative Strength Differences at Short-Term Follow-Up Vary Based on Autograft Harvest Site After Adolescent Transphyseal Anterior Cruciate Ligament Reconstruction

PURPOSE

To compare the clinical and patient-reported outcomes of adolescent patients who underwent anterior cruciate ligament reconstruction (ACLR) with quadriceps tendon (QT) versus hamstring tendon (HT) autograft.

METHODS

This was a retrospective cohort study of adolescent patients aged 18 years or younger treated at a single tertiary care children's hospital who underwent primary transphyseal ACLR using QT or HT between January 2018 and December 2019. All patients had minimum 6-month follow-up. Outcomes included isokinetic strength testing, postoperative Patient-Reported Outcomes Measurement Information System and International Knee Documentation Committee scores, and complications; these were compared between the QT and HT cohorts.

RESULTS

A total of 84 patients (44 HT and 40 QT patients) were included. The QT cohort had a higher proportion of male patients (62.5% vs 34.1%, P = .01). At 3 months, HT patients had a lower hamstring-quadriceps (H/Q) strength ratio (60.7 ± 11.0 vs 79.5 ± 18.6, P < .01) and lower Limb Symmetry Index in flexion (85.6 ± 16.1 vs 95.5 ± 15.7, P = .01) whereas QT patients had a lower Limb Symmetry Index in extension (67.3 ± 9.5 vs 77.4 ± 10.7, P < .01). The H/Q ratio at 6 months was lower in HT patients (59.4 ± 11.5 vs 66.2 ± 7.5, P < .01). Patient-Reported Outcomes Measurement Information System and International Knee Documentation Committee scores were not different at 3 months or latest follow-up. QT patients had more wound issues (20.0% vs 2.3%, P = .01). Patients receiving HT autograft had more ipsilateral knee injuries (18.2% vs 2.5%, P = .03), but there was no difference in graft failure for ACLR using HT versus QT (9.1% vs 2.5%, P = .36).

CONCLUSIONS

There were no differences in patient-reported outcome measures between patients receiving QT autografts and those receiving HT autografts. Patients with QT grafts had more postoperative wound issues but a lower rate of ipsilateral knee complications (graft failure or meniscal tear). Differences in quadriceps and hamstring strength postoperatively compared with the contralateral limb were observed for adolescent ACLR patients receiving QT and HT autografts, respectively. This contributed to higher H/Q ratios seen at 3 and 6 months postoperatively for patients receiving QT autografts.

LEVEL OF EVIDENCE

Level III, retrospective comparative therapeutic study.

Comparison of Graft Type and Fixation Method in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis Based on Randomized Control Studies

BACKGROUND

The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee. ACL reconstruction (ACLR) proves the standard for treating this injury. However, graft choice and method of fixation remain a heavily debated topic. This study investigates the following: bone-patellar tendon-bone (BPTB) vs. hamstring tendon (HT) autograft, single-bundle vs. double-bundle hamstring graft, and metal vs. bioabsorbable screws in ACLR.

METHODS

A systematic review was performed on PubMed and Google Scholar according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were collected on patient demographics, complications, and functionality scores including International Knee Documentation Committee (IKDC) and Lysholm scores. A systematic review and meta-analysis were conducted with Review Manager. Outcome measurements were determined using forest plots with significant differences considered p < 0.05.

RESULTS

Twenty-five studies were included, accounting for 2,170 patients. No statistically significant difference was appreciated when comparing BPTB to hamstring autografts. Patients who received a double bundle HT autograft exhibited significantly superior outcomes in terms of revision (p = 0.05), failure (p = 0.002), normal pivot shift tests (p = 0.04), and normal IKDC (p = 0.008). When comparing screw types, bioabsorbable screws had a greater Lysholm score (p = 0.01) and lower failure rates for copolymer screws (p = 0.03).

CONCLUSION

Overall, the data collected suggested that BPTB and HT autografts display similar postoperative results. However, if an HT autograft is used, the data suggest a double-bundle graft improves both functionality and decreases the possible complications. Finally, bioabsorbable screws prove superior to metal screws when looking at both functionality and failure rates. Further research into the superior graft type is still needed.

LEVEL OF EVIDENCE

Level II. See Instructions for Authors for a complete description of levels of evidence.

Reconstruction of Coracoclavicular Ligaments with Semitendinosus Autograft and Temporary Kirschner Wires is a good option for Chronic Acromioclavicular Joint Instability

Introduction

This study reports the results of surgical anatomic reconstruction of torn coracoclavicular ligaments with an autogenous semitendinosus graft and temporary Kirschner wires (K-wires) in chronic acromioclavicular (AC) joint dislocations.

Materials and methods

Nineteen shoulders underwent surgical anatomic reconstruction of torn coracoclavicular (CC) ligaments with an autogenous semitendinosus tendon graft and temporary K-wires for Rockwood grade III, IV and V chronic AC joint dislocations. Pre-operative data included patients' demographic characteristics, injury characteristics and surgical histories. The primary outcome measures were the University of California Los Angeles (UCLA) shoulder rating scale and visual analogue pain scoring (VAS), and the complications were noted for each patient.

Results

Surgical anatomic reconstruction of torn CC ligaments was performed in 19 patients with a mean age of 41.6±16 years (range 21-72 years). All of the patients were satisfied and felt better after CC ligament reconstruction. The average UCLA shoulder rating scale score was good/excellent: 29.4 (range 23-34) out of 35 points. The average pre-operative VAS score was 7.7 points out of 10 and improved to 1.1 points post-operatively (p<0.05). None of the patients experienced failure during the follow-up. One patient had a mild subluxation, but the patient was satisfied with the result.

Conclusions

This technique is simple, reliable, and biologic without major complications. It is also a cost-effective procedure since it can be performed with Kirschner wires and autogenous grafts. It has a major advantage of leaving no implants inside the joint, which can lead to hardware complications, and it can be performed in basic operating room settings.

Modified Anatomical Anterior Cruciate Ligament Reconstruction with Flat Semitendinosus Graft and C-shaped Tibial Canal

Every year, approximately 400,000 patients undergo anterior cruciate ligament (ACL) reconstruction surgery in the United States, accounting for almost 50% of all knee surgeries in the country. Recent studies have demonstrated that the ACL is a ribbon-like structure with a C-shaped tibial insertion and a flat femoral origin. This article introduces a modification of an ACL reconstruction technique. The modification renders the procedure easily reproducible with standard surgical instruments. We will describe a surgical technique modification that goes beyond the standard round bone tunnels and adopts a more anatomical approach using a C-shaped tibial canal and a flat femoral canal using a flat semitendinosus (semi-T) graft. The use of a semi-T graft better reproduces the ribbon-like ACL anatomy. The semi-T graft, a flat femoral canal, and a C-shaped tibial canal provide increased bone-tendon contact surface area and decreased diffusion length, resulting in improved tendon-bone healing. The modification proposed by our team makes the anatomical ribbon-like ACL graft, C-shaped tibial canal, and the flat femoral canal technique feasible in every orthopaedic operating room and mitigates costly specialized instrument.

Earlier Return to Sports, Reduced Donor-Site Morbidity with Doubled Peroneus Longus Versus Quadrupled Hamstring Tendon Autograft in ACL Reconstruction

Background

Graft choice for anterior cruciate ligament reconstruction (ACLR) has been evolving. The peroneus longus tendon (PLT) has been seen as a suitable choice for ACLR, providing comparable results to those of hamstring tendon (HT) autograft, but its clinical relevance in terms of return to sports, to our knowledge, has not been studied.

Methods

Two hundred and thirty-two patients who sustained an isolated ACL injury were enrolled and underwent ACLR using doubled PLT autograft or quadrupled HT autograft; 158 were followed for 24 months. Functional scores (International Knee Documentation Committee [IKDC] and Tegner-Lysholm scores) were assessed preoperatively and at 3,6, 12, and 24 months postoperatively. Graft diameter and graft harvesting time were measured intraoperatively. Donor-site morbidity was evaluated using subjective evaluation. Time to return to sports in both groups was compared.

Results

The mean diameter of PLT autograft was significantly larger than that of HT autograft, and the mean graft-harvesting time was less (p < 0.001). Patients in the PLT group returned to sports a mean of 34 days earlier than those in the HT group (p < 0.001) and had a lower rate of donor-site morbidity and, at 6 months, better patient-reported outcomes at the knee (p < 0.001). There were no significant differences between the groups in the rate of graft rupture or in IKDC and Tegner-Lysholm scores at the 24-month follow-up.

Conclusions

PLT is a suitable autograft for ACLR in terms of graft diameter and graft-harvesting time and may offer athletes an earlier return to sports related to better outcomes at 6 months of follow-up. HT autograft was associated with increased thigh weakness. Both grafts, however, performed similarly at 24 months postoperatively.

Level of Evidence

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Free tendon grafts for surgical management of chronic tears of the main body of the Achilles tendon: a systematic review

PURPOSE

After four weeks from injury, tears of the Achilles tendon are considered chronic. Their management is challenging, and the use of a graft is suggested when the gap between proximal and distal stumps is greater than 6 cm. The present study systematically reviews the outcome of free tendon grafts in chronic ruptures of the Achilles tendon, evaluating clinical outcomes, complications and return to sport.

METHODS

The present study was conducted according to the PRISMA 2020 guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in February 2023. All the published clinical studies reporting clinical outcome, return to sport and complications of free tendon grafts used the treatment of chronic rupture of the midportion of the Achilles Tendon were accessed. The mean CMS (Coleman Methodology Score) of 65.7 suggested an overall good quality of the available published articles, attesting to the low risk of bias.

RESULTS

Data from 22 articles (368 patients with a mean age of 47 years) were retrieved. The average time from rupture to surgery was 25.1 week. At last follow-up, the AOFAS (American Orthopaedic Foot and Ankle Surgery) and ATRS (Achilles Tendon Total Rupture Score) scores improved of 33.8 (P = 0.0004), and 45.1 points (P = 0.0001) respectively. Return to activity was reported in 105 patients, and 82 (78.1%) had no activity limitations, while 19 (18.1%) had limited recreational but not daily activity limitations, and 4 (3.8%) reported limitations in daily activities. Return to sport data was reported in six studies, and 45 of 93 (48.4%) patients returned to sport at an average of 22.6 weeks.

CONCLUSION

In chronic tears of the Achilles tendon, with a gap of at least 6 cm, free tendon grafts allow predictable return to sport and acceptable recovery function.

LEVEL OF EVIDENCE

Level IV.

Arthroscopic Single-Bundle Anterior Cruciate Ligament Reconstruction Using the Quadrupled Hamstring Tendon Graft: A Single-Institution Experience From North-Eastern India

Background There is a lack of literature regarding the arthroscopic approach to a single-bundle anterior cruciate ligament (ACL) reconstruction using the quadrupled hamstring tendon graft in the north-eastern Indian population. Methodology A prospective, single-center study was planned for patients with ACL tears according to the eligibility criteria and with a defined surgical protocol. Patients were followed up from the preoperative period for at least one year, and knee function was evaluated using the International Knee Documentation Committee (IKDC) subjective knee score and the Lysholm knee score. Results A total of 29 patients were followed up for a mean of 14.6 months (12-22 months). The mean age of patients was 26.83 ± 7.50 years, with a male:female ratio of 4.8:1 and almost equal involvement of both knees. There was statistically significant improvement (p<0.001) in results in the Lachman test, anterior drawer test, pivot shift test, IKDC score, and Lysholm score. No intraoperative or postoperative complications were found in the present study. Discussion The study shows that arthroscopic anatomical single-bundle ACL reconstruction using quadrupled hamstring tendon grafts is a minimally invasive, safe, and effective procedure that provides anteroposterior and rotational stability and good to excellent functional outcomes.

The Lasso-Loop Technique: A Simple Way to Attach the Semitendinosus Tendon to an Endobutton Device

During reconstruction of the anterior cruciate ligament, graft preparation is an essential step. The semitendinosus tendon is most frequently used, usually with a 4-strand graft and endobutton fixation. Our lasso-loop technique for tendon fixation is rapid and without sutures, providing a graft with a regular diameter, with no weak points and satisfactory primary stability.

Hamstring autograft utilization in reconstructing anterior cruciate ligament: Review of harvesting techniques, graft preparation, and different fixation methods

Rupture of the anterior cruciate ligament (ACL) is a common orthopedic injury. Various graft options are available for the reconstruction of ruptured ACL. Using the hamstring muscle as an autograft was first described in 1934, and it remains a commonly harvested graft for ACL reconstruction. Hamstring autografts can be harvested using the traditional anteromedial approach or the newer posteromedial technique. An isolated semitendinosus tendon can be used or combined with the gracilis tendon. There are numerous methods for graft fixation, such as intra-tunnel or extra-tunnel fixation. This comprehensive review discusses the different hamstring muscle harvesting techniques and graft preparation options and fixation methods. It provides a comprehensive overview for choosing the optimal surgical technique when treating patients.

Arthroscopic Reconstruction of ACL and LCL Tear with Combined Asymmetric Hamstring Graft Using Single Femoral Tunnel - A Case Report

Introduction

Anterior cruciate ligament (ACL) injury is associated with various degrees of rotational deformity. About 15% have a positive pivot shift test after accurate ACL reconstruction. Unrepaired lateral collateral ligament (LCL) tear can lead to increase load on reconstructed ACL and lead to ligament failure.

Case Report

We present a case of combined ACL with LCL tear treated arthroscopically using a single femoral tunnel and asymmetric combined semitendinosus and gracilis (STG) graft. The patient had full range of motion at the knee joint and was able to squat and sit cross-legged and was able to carry out activities of daily living at 8 months of follow-up.

Conclusion

Our technique provides orthopedic surgeons with an alternative for combined ACL and LCL reconstruction with a single combined STG graft, thereby limiting additionally graft site morbidity and avoiding the need for allograft and preserving adequate femoral bone stock by preparing only a single femoral tunnel and thus limiting the cost to the patient using single implant for femur.

Hamstring, bone-patellar tendon-bone, quadriceps and peroneus longus tendon autografts for primary isolated posterior cruciate ligament reconstruction: a systematic review

INTRODUCTION

Several autografts are available to reconstruct the posterior cruciate ligament (PCL).

SOURCE OF DATA

Current scientific literature published in PubMed, Google scholar, Embase and Scopus.

AREAS OF AGREEMENT

Hamstring, bone-patellar tendon-bone (BPTB), quadriceps and peroneus longus (PLT) are the most common tendon autografts used for primary isolated PCL reconstruction.

AREAS OF CONTROVERSY

The optimal tendon source for PCL reconstruction remains nevertheless debated. Identifying the most suitable tendon autograft could assist the surgeon during primary PCL reconstruction.

GROWING POINTS

The present study compared the outcome of PCL reconstruction using hamstring, BPTB, quadriceps and PLT autografts. The focus was on patient-reported outcome measures (PROMs), joint laxity, range of motion and complications.

AREAS TIMELY FOR DEVELOPING RESEARCH

All autografts are viable options for PCL reconstruction, with BTB and hamstring autografts demonstrating superior PROMs. However, further clinical investigations are required to determine the ideal autograft construct.

Similar biomechanical properties of four tripled tendon graft models for ACL reconstruction

PURPOSE

The present study tested and compared the biomechanical properties of four different triplicate graft tendon techniques.

METHODS

32 tripled tendons from the common extensor muscle of bovine fingers were tested on a material testing machine, passing the end loop over a metal rod of a clevis connected to the load cell on the upper side, and fixing the lower end to a clamp. The samples were divided into four groups: (A) tripled with a free end sutured only to one of the two fixed bundles (B) tripled with a free end positioned between the two fixed strands and sutured to both (C) tripled with an S-shape and all the three strands sutured together at the upper and lower extremities of the graft (D) partially quadrupled with the free end sutured together with the other three bundles at the upper extremity. Each sample was pretensioned at 50 N for 10 min and then subjected to 1000 load control cycles between 50 and 250 N. Finally, each sample was subjected to a load to failure test. Authors also present some preliminary results on the feasibility of a non-contact and full-field Thermoelastic Stress Analysis technique, based on Infrared Thermography, to evaluate the level of stress on the whole graft, and hence on each strand, during fatigue loading.

RESULTS

Eighty five percent of the samples failed at the level of the clamp. The cyclical elongation progressively decreased in all the samples and there was a simultaneous increase in stiffness. An increased stiffness was noted between Group 2 vs Group 3 and Group 2 vs Group 4 at the 500th and 1000th cycle. The failure loads were as follows: (a) 569.10 N, (b) 632.28 N, (c) 571.68 N, (d) 616.95 N. None of the parameters showed a statistically significant difference between the four groups.

CONCLUSION

This study reported similar biomechanical behavior of four different models of tripled grafts suitable for ACL reconstruction. In addition, the biomechanics of overall tripled tendon grafts seems more affected by the viscoelastic property of the tendon itself rather than the preparation method.

An Efficient Needleless Grasping Suture Technique for Graft Preparation in Anterior Cruciate Ligament Reconstruction

Objective

Several needleless techniques have been developed to outcome the inherent disadvantages of the traditional needle stitching technique for graft preparation, such as tendon damage through the needle, time consumption, and the potential risk of needlestick injury. The purpose of the present study is to compare the graft preparation time and the biomechanical performance between an efficient needleless technique and the traditional needle stitching technique for graft preparation in anterior cruciate ligament reconstruction (ACLR).

Methods

The time required to perform a complete suture on 20 hamstring tendons during ACLRs was measured. The grafts from one side were prepared using the needle stitching technique. The grafts from the other side used the needleless grasping suture technique. For the second part of the study, 12 fresh-frozen porcine flexor tendons were divided into two groups using two techniques and were mounted in an electric tensile test system. Each group was pretensioned to 100 N to simulate the maximum initial graft tension. The suturing state of sutures and graft (intact and damaged) and the load-elongation curve were recorded for each group. A Student’s t-test was used to compare the means of the two groups.

Results

In operation, the needleless grasping suture technique group (19.8 ± 4.8, range: 13.5–32.9 s) was significantly faster (p &lt; 0.05) than the needle stitching technique group (52.7 ± 12.7, range: 36.0–87.5 s). The state of sutures in each group was intact. The mean elongation was 11.75 ± 1.38 (range: 9.47–12.99) mm and 10.59 ± 1.02 (range: 9.12–11.76) mm in the needleless stitching technique group and the needle grasping suture technique group, respectively. There was no statistically significant difference in the elongation between the two groups (p &gt; 0.05).

Conclusion

The needleless grasping suture technique was a convenient and efficient method for graft preparation in ACLR.

Comparative Analysis of Arthroscopic Tight Rope ACL Reconstruction Using four Strand Isolated Semitendinosus Graft and Quadrupled Combined Hamstring Graft

BACKGROUND

Arthroscopic ACL reconstruction using hamstring autograft is a quite a popular surgical procedure. But there is a conflict regarding the use of isolated semitendinosus graft or a combined hamstring graft. We did a comparative analysis of the functional outcome after ACL reconstruction performed with four strand semitendinosus graft and a combined hamstring graft over tightrope.

METHODS

Two groups of 30 patients each with similar demographic profiles, presenting with symptoms of instability after chronic ACL tear were included. A standard single bundle arthroscopic ACL reconstruction was performed by using four-strand semitendinosus graft in Group A and combined hamstring graft in Group B patients. Clinical and functional outcome analysis was done using quantitative anterior tibial translation measurement and Lysholm score.

RESULTS

The mean age of subjects in group A was 29 years and in Group B was 28 years. The semitendinosus graft length was insufficient in 13.33% cases in group A. The improvement in Lysholm score and the decrease in the tibial translation were comparable in both the groups at one year of follow-up. No added comorbidities were noted in additional removal of gracilis tendon in group B patients.

CONCLUSION

Isolated semitendinosus four-strand autograft can be used for arthroscopic single bundle ACL reconstruction when adequate graft length is obtained. However, one should not be hesitant in additional removal of gracilis tendon when needed. In terms of functional outcome and patient satisfaction, both the graft configurations stand the same.

Anterior Cruciate Ligament Length in Pediatric Populations: An MRI Study

Background:

As regards anterior cruciate ligament (ACL) reconstruction (ACLR), graft diameter has been identified as a major predictor of failure in skeletally mature patients; however, this topic has not been well-studied in the higher risk pediatric population. Hamstring tendon autograft configuration can be adjusted to increase graft diameter, but tendon length must be adequate for ACLR. Historical parameters of expected tendon length have been variable, and no study has quantified pediatric ACL morphology with other osseous parameters.

Purpose:

To develop magnetic resonance imaging (MRI)–derived predictors of native ACL graft length in pediatric patients so as to enhance preoperative planning for graft preparation in this skeletally immature patient population.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

MRI scans of 110 patients were included (64 girls, 46 boys; median age, 10 years; range, 1-13 years). Patients with musculoskeletal diseases or prior knee injuries were excluded. The following measurements were taken on MRI: ACL length; sagittal and coronal ACL inclination; intercondylar notch width and inclination; and femoral condyle depth and width. Associations between these measurements and patient sex and age were investigated. Univariate linear regression and multivariable regression models were created for each radiographic ACL measure to compare R².

Results:

Female ACL length was most strongly associated with the depth of the lateral femoral condyle as viewed in the sagittal plane (R² = 0.65; P < .001). Other statistically significant covariates of interest included distal femoral condylar width, age, and coronal notch width (P < .05). For males, the ACL length was most strongly associated with the distal femoral condyle width as viewed in the coronal plane (R² = 0.70; P < .001). Other statistically significant covariates of interest for male ACL lengths were lateral femoral condyle depth, age, and coronal notch width (P < .05).

Conclusion:

In pediatric populations, femoral condylar depth/width and patient age may be valuable in assessing ACL size and determining appropriate graft dimensions and configuration for ACLRs. The use of this information to optimize graft diameter may lower the rates of ACL graft failure in this high-risk group.

Hamstring graft diameter above 7 mm has a lower risk of failure following anterior cruciate ligament reconstruction

PURPOSE

Multi-stranded hamstring-tendon autografts have been widely used for anterior cruciate ligament reconstruction (ACLR) surgeries. Recently, smaller diameter hamstring autografts have been linked with the risk of failure or graft rupture. However, there is limited evidence concerning the optimal diameter of the hamstring autografts for ACLR. The current systematic review and meta-analysis analysed the association of ACLR failure with the diameter of hamstring autografts.

METHODS

A systematic search of three major scientific databases (Pubmed, EMBASE, and Cochrane library) was conducted to identify studies that presented ACLR failure-related outcomes with different diameters of hamstring autografts. The pooled data from the included studies were analysed to investigate the association between ACLR failure and the cut-off diameters of 6, 7, 8, and 9 mm. Subgroup analyses based on the level of evidence and follow-up duration were also performed at each cut-off diameter.

RESULTS

Of the 2282 studies screened, 16 reported failure rates with hamstring autografts of different diameters, 15 of which were included in the meta-analysis. A graft diameter ≥ 7 mm was associated with significantly lower ACLR failure rates than a graft diameter < 7 mm (p = 0.005), based on pooled data of 19,799 cases. Age < 20 years and higher physical activity were associated with significantly higher ACLR failure rates.

CONCLUSION

The current systematic review suggests that the hamstring graft diameter for ACLR should be more than 7 mm considering the significantly higher failure rates with graft diameters less than 7 mm.

LEVEL OF EVIDENCE

Level IV.

Local variations in mechanical properties of human hamstring tendon autografts for anterior cruciate ligament reconstruction do not translate to a mechanically inferior strand

A ruptured anterior cruciate ligament (ACL) is often reconstructed with a multiple-strand autograft of a semitendinosus tendon alone or combined with a gracilis tendon. Up to 10% of patients experience graft rupture. This potentially results from excessive local tissue strains under physiological loading which could either result in direct mechanical failure of the graft or induce mechanobiological weakening. Since the original location in the hamstring tendon cannot be traced back from an autograft rupture site, this study explored whether clinical outcome could be further improved by avoiding specific locations or regions of human semitendinosus and/or gracilis tendons in ACL grafts due to potential mechanical or biochemical inferiority. Additionally, it examined numerically which clinically relevant graft configurations experience the lowest strains - and therefore the lowest rupture risk - when loaded with equal force. Remnant full-length gracilis tendons from human ACL reconstructions and full-length semitendinosus- and ipsilateral gracilis tendons of human cadaveric specimens were subjected to a stress-relaxation test. Locations at high risk of mechanical failure were identified using particle tracking to calculate local axial strains. As biochemical properties, the water-, collagen-, glycosaminoglycan- and DNA content per tissue region (representing graft strands) were determined. A viscoelastic lumped parameter model per tendon region was calculated. These models were applied in clinically relevant virtual graft configurations, which were exposed to physiological loading. Configurations that provided lower stiffness - i.e., experiencing higher strains under equal force - were assumed to be at higher risk of failure. Suitability of the gracilis tendon proper to replace semitendinosus muscle-tendon junction strands was examined. Deviations in local axial strains from the globally applied strain were of similar magnitude as the applied strain. Locations of maximum strains were uniformly distributed over tendon lengths. Biochemical compositions varied between tissue regions, but no trends were detected. Viscoelastic parameters were not significantly different between regions within a tendon, although semitendinosus tendons were stiffer than gracilis tendons. Virtual grafts with a full-length semitendinosus tendon alone or combined with a gracilis tendon displayed the lowest strains, whereas strains increased when gracilis tendon strands were tested for their suitability to replace semitendinosus muscle-tendon junction strands. Locations experiencing high local axial strains - which could increase risk of rupture - were present, but no specific region within any of the investigated graft configurations was found to be mechanically or biochemically deviant. Consequently, no specific tendon region could be indicated to provide a higher risk of rupture for mechanical or biochemical reasons. The semitendinosus tendon provided superior stiffness to a graft compared to the gracilis tendon. Therefore, based on our results it would be recommended to use the semitendinosus tendon, and use the gracilis tendon in cases where further reinforcement of the graft is needed to attain the desired length and cross-sectional area. All these data support current clinical standards.

THE EFFECTS OF NEUROMUSCULAR ELECTRICAL STIMULATION IN ASSOCIATION WITH WHEY PROTEIN SUPPLEMENTATION AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

OBJECTIVE

To analyze the effects of neuromuscular electrical stimulation of the femoral quadriceps associated or not with whey protein supplementation on the electromyographic activity and body mass distribution in volunteers undergoing anterior cruciate ligament reconstruction.

METHODS

24 volunteers were randomly divided into three groups: basal control, whey protein in association with neuromuscular electrical stimulation, and neuromuscular electrical stimulation alone.

RESULTS

In the postoperative evaluation, during the mini squat, the basal group showed a decrease in the electromyographic activity of the vastus medialis (p = 0.005, eyes open; p = 0.003, eyes closed), vastus lateralis (p = 0.005, eyes open; p = 0.020; eyes closed) and rectus femoris (p = 0.075, eyes open; p = 0.074, eyes closed) and of body mass distribution in the injured limb (p < 0.001, eyes open; p < 0.001, eyes closed), and in the healthy limb (p < 0.001, eyes open; p < 0.001, eyes closed).

CONCLUSION

The early use of neuromuscular electrical stimulation of the quadriceps femoris maintained the electromyographic activity of the vastus medialis and vastus lateralis muscles and prevented asymmetries in body mass distribution 15 days after anterior cruciate ligament reconstruction. Level of Evidence I, High quality randomized trial.

Tendon grafts with preserved muscle demonstrate similar biomechanical properties to tendon grafts stripped of muscular attachments: a biomechanical evaluation in a porcine model

Purpose

(1) To evaluate the biomechanical properties of a porcine flexor digitorum superficialis tendon graft with preserved muscle fibers and (2) to compare these results with the biomechanical properties of a porcine tendon graft after removal of associated muscle.

Methods

Eighty-two porcine forelegs were dissected and the flexor digitorum superficialis muscle tendons were harvested. The study comprised of two groups: Group 1 (G1), harvested tendon with preserved muscle tissue; and Group 2 (G2), harvested contralateral tendon with removal of all muscle tissue. Tests in both groups were conducted using an electro-mechanical material testing machine (Instron, model 23-5S, Instron Corp., Canton, MA, USA) with a 500 N force transducer. Yield load, stiffness, and maximum load were evaluated and compared between groups.

Results

The behavior of the autografts during the tests followed the same stretching, deformation, and failure patterns as those observed in human autografts subjected to axial strain. There were no significant differences in the comparison between groups for ultimate load to failure (p = 0.105), stiffness (p = 0.097), and energy (p = 0.761).

Conclusion

In this porcine model biomechanical study, using autograft tendon with preserved muscle showed no statistically significant differences for yield load, stiffness, or maximum load compared to autograft tendon without preserved muscle. The preservation of muscle on the autograft tendon did not compromise the mechanical properties of the autograft.

Level of evidence

Level III Controlled laboratory study

Repair versus reconstruction for proximal anterior cruciate ligament tears: a study protocol for a prospective multicenter randomized controlled trial

Background

For active patients with a tear of the anterior cruciate ligament (ACL) who would like to return to active level of sports, the current surgical gold standard is reconstruction of the ACL. Recently, there has been renewed interest in repairing the ACL in selected patients with a proximally torn ligament. Repair of the ligament has (potential) advantages over reconstruction of the ligament such as decreased surgical morbidity, faster return of range of motion, and potentially decreased awareness of the knee. Studies comparing both treatments in a prospective randomized method are currently lacking.

Methods

This study is a multicenter prospective block randomized controlled trial. A total of 74 patients with acute proximal isolated ACL tears will be assigned in a 1:1 allocation ratio to either (I) ACL repair using cortical button fixation and additional suture augmentation or (II) ACL reconstruction using an all-inside autologous hamstring graft technique. The primary objective is to assess if ACL repair is non-inferior to ACL reconstruction regarding the subjective International Knee Documentation Committee (IKDC) score at two-years postoperatively. The secondary objectives are to assess if ACL repair is non-inferior with regards to (I) other patient-reported outcomes measures (i.e. Knee Injury and Osteoarthritis Outcome Score, Lysholm score, Forgotten Joint Score, patient satisfaction and pain), (II) objective outcome measures (i.e. failure of repair or graft defined as rerupture or symptomatic instability, reoperation, contralateral injury, and stability using the objective IKDC score and Rollimeter/KT-2000), (III) return to sports assessed by Tegner activity score and the ACL-Return to Sports Index at two-year follow-up, and (IV) long-term osteoarthritis at 10-year follow-up.

Discussion

Over the last decade there has been a resurgence of interest in repair of proximally torn ACLs. Several cohort studies have shown encouraging short-term and mid-term results using these techniques, but prospective randomized studies are lacking. Therefore, this randomized controlled trial has been designed to assess whether ACL repair is at least equivalent to the current gold standard of ACL reconstruction in both subjective and objective outcome scores.

Trial registration

Registered at Netherlands Trial Register (NL9072) on 25th of November 2020.

Evolution in ACL Autograft Harvesting Techniques: Transition to Minimally Invasive Autograft Harvesting

Surgical techniques for anterior cruciate ligament (ACL) reconstruction continue to evolve. Harvesting techniques for commonly used ACL autografts such as bone patellar tendon bone, hamstring, and quadriceps tendon have similarly continued to progress. Traditional larger incisions for graft harvesting that were described in the 1980s have given way to smaller or more minimally invasive techniques. Advantages of these techniques are primarily anatomy based and include the following: decreased nerve complaints such as hypoesthesia or dysesthesia, improved cosmesis, decreased surgical site pain or morbidity, and, in the case of hamstring harvesting, easier tendon identification. The current literature supports reproducible minimally invasive or modified graft harvesting techniques for bone patellar tendon bone, hamstring, and quadriceps tendon autografts. Specialized instrumentation is available to simplify the harvesting process. Each of these techniques is described in detail outlining surgical steps, technical considerations, and precautions. Knowledge and review of these techniques provides the surgeon with greater flexibility and options when choosing and harvesting autograft tissue for ACL reconstruction.

Posterior cruciate ligament reconstruction with peroneus longus tendon versus hamstring tendon: a comparison of functional outcome and donor site morbidity

PURPOSE

This study aimed to evaluate the differences in clinical outcome and donor site morbidity between the Peroneus Longus Tendon (PLT) and Hamstring Tendon (HT) in single-bundle Posterior Cruciate Ligament (PCL) reconstruction.

METHODS

Patients with an isolated PCL injury underwent single-bundle PCL reconstruction using consecutive sampling. Patients were allocated into two groups (PLT and HT) and prospectively observed. The tendon graft diameter was measured intraoperatively. Functional scores (IKDC, Lysholm, and modified Cincinnati scores) were recorded preoperatively and 2 years postoperatively. The thigh circumference and functional score according to the Foot and Ankle Disability Index (FADI) and American Orthopedic Foot and Ankle Society (AOFAS) were recorded to evaluate the morbidities in the ankle.

RESULTS

Fifty-five patients (hamstring n = 27, peroneus n = 28) met the inclusion criteria. The diameter of the PLT graft (8.2 ± 0.6 mm) was comparable to that of the HT graft (8.3 ± 0.5 mm). Both groups had excellent postoperative knee functional outcome scores. The mean AOFAS and FADI scores were excellent, with no difference in thigh circumference between the groups.

CONCLUSION

PLT is a good choice as a graft in PCL reconstruction at the 2-year follow-up, with minimal donor site morbidity.

LEVEL OF EVIDENCE

II.

Four-Strand Hamstring Diamond Braid Technique for Anterior Cruciate Ligament Reconstruction

Several factors affect the success of an anterior cruciate ligament reconstruction, including graft origin, type, and morphology. Hamstring and bone-patellar tendon-bone autografts are the most widely used, and there are many different techniques of graft preparation with each. In this Technical Note and accompanying video, a 4-strand hamstring autograft technique is described that uses a simple diamond-type braid to produce a more ovoid morphology with increased cross-sectional area. Increased graft diameters have been associated with higher success rates and more positive long-term outcomes. Therefore, this braiding construct may provide additional tensile strength with increased resistance to failure than grafts that are otherwise undersized using conventional techniques.

Viscoelastic and failure properties of two configurations of triple-folded hamstring tendons used for anterior cruciate ligament (ACL) reconstruction

BACKGROUND

Hamstring autografts are commonly used for anterior cruciate ligament (ACL) reconstruction. Different folding techniques exist in tripling the semitendinosus. Few anatomical studies exist in evaluating their viscoelastic properties. The purpose of this study was to characterize and compare the viscoelastic and failure properties of two hamstring graft configurations, the "Z" construct and "2" construct.

METHODS

Ten matched pairs of fresh-frozen cadaveric semitendinosus hamstring grafts were used to create the "2" configuration or "Z" configuration. The biomechanical testing consisted of four phases: preconditioning, where graft dimensions (mm) were measured; stress relaxation, where load, displacement and time data were collected and equilibrium relaxation (%) was calculated; dynamic creep, where the total construct elongation was calculated; and ramp-to-failure, where maximum failure load was recorded.

RESULTS

The "2" configuration demonstrated recorded forces (N) significantly greater at each time point when compared to the "Z" configuration during stress relaxation (p = 0.003). The "2" configuration exhibited significantly less construct elongation (mm) during dynamic creep at 10 cycles (p = 0.008) and 2000 cycles (p = 0.0001). The maximum measured load at failure was significantly greater in the "2" configuration constructs than "Z" configuration (p = 0.013). Moreover, the axial loads at 2, 3 and 4 mm of displacement were, on average, greater in the "2" configuration than "Z" configuration (p = 0.152; p = 0.080; p = 0.012), respectively.

CONCLUSION

The results of this study provide support for folding techniques for tripled grafts to provide higher viscoelastic and failure properties for techniques with less suture interfaces. Future studies can potentially evaluate the clinical significance of these findings.

Anterior Cruciate Ligament Reconstruction Using Combined Graft of Hamstring and Fascia Lata With Extra-articular Tenodesis. A Technique in Case of Insufficient Hamstrings

A technique for augmentation of the anterior cruciate ligament (ACL) with hamstring graft and lateral extra-articular tenodesis is presented. The patient is positioned supine with the knee flexed 90°. First, intra-articular injuries are addressed arthroscopically, and then autologous hamstring tendons are harvested and measured; the present technique is a resource for cases with a very small graft diameter (less than 8 mm), due to thin tendons or to tendon breakage, even after tripling the hamstring graft, which is prepared using a facia lata strip long enough to fit the lengths of the femoral tunnel, the anterior cruciate ligament graft, and the tibial tunnel. A single femoral tunnel is performed and only 2 interference screws are needed for fixation.

Quadrupled Semitendinosus ACL Reconstruction Combining Cortical Button in Femur and Interference Screw in Tibia

Anterior cruciate ligament (ACL) reconstruction with hamstring tendons has gained popularity in the past and is the most used type of graft in several national registries. It usually involves the harvest of both gracilis and semitendinosus tendons from the ipsilateral knee. More recently, the use of only 1 of the tendons (semitendinosus) in a tripled or quadrupled arrangement has been described, especially in an all-inside type of reconstruction. Having a thicker tendon with a quadrupled semitendinosus (ST), instead of double gracilis and ST enables to a have a graft with enough diameter to resemble more closely the native ACL and decreases the risk of graft rerupture. This Technical Note aims to present a way of reconstructing the ACL using a quadrupled ST graft, with suspensory cortical button in femur and interference screw in tibia, as an alternative to the all-inside technique.

Biomechanical Comparison of Quadriceps and 6-Strand Hamstring Tendon Grafts in Anterior Cruciate Ligament Reconstruction

Background:

The quadriceps tendon is becoming a popular graft option for anterior cruciate ligament (ACL) reconstruction. Few studies have examined the biomechanics of the quadriceps tendon compared with more commonly used graft choices. Due to the risk associated with small-diameter hamstring tendon grafts, various modifications of hamstring tendon preparation techniques have been described—specifically, a tripled, 6-strand hamstring tendon construct. This is the first study to directly compare the biomechanical properties of quadriceps tendon and hamstring tendon grafts.

Purpose/Hypothesis:

The purpose of this study was to quantify the biomechanical properties of the quadriceps tendon and 6-strand hamstring tendon grafts, specifically evaluating ultimate load to failure, load at 3 mm of displacement, and stiffness. These parameters characterize the time zero, in vitro, static tensile properties of these graft options. Our hypothesis was that for grafts of similar size, there would not be a significant difference in the biomechanical properties.

Study Design:

Controlled laboratory study.

Methods:

Quadriceps and hamstring tendon grafts were harvested from 6 human cadaveric knees (mean age, 61.17 ± 10.38 years). These matched grafts were prepared and biomechanically tested using an all-electric dynamic test load system. The mean diameter, stiffness, ultimate load to failure, and load to 3 mm of displacement were evaluated and analyzed.

Results:

The mean diameters of the 6-strand hamstring and quadriceps tendons were 11.33 and 10.16 mm, respectively (P = .03). Despite these significantly different diameters, no differences were found in graft ultimate load to failure or load at 3 mm of displacement. The 6-strand hamstring tendon graft was significantly stiffer compared with the quadriceps tendon (1147.65 vs 808.65 N/mm; P = .04).

Conclusion:

The 6-strand hamstring tendon and quadriceps tendon graft had similar biomechanical properties with respect to ultimate load to failure and load at 3 mm of displacement in 6 matched cadaveric specimens. Both grafts were significantly stiffer than the native ACL, and the hamstring tendon construct was significantly stiffer than the quadriceps tendon.

Clinical Relevance:

The quadriceps tendon graft is a reliable alternative to a 6-strand hamstring tendon graft for ACL reconstruction.

Hamstring Braid Graft Technique for Anterior Cruciate Ligament Reconstruction

Hamstring autograft is one of the most used grafts for anterior cruciate ligament (ACL) reconstruction, although there are several graft preparation techniques. It is extremely difficult to mimic the biomechanical properties of the native ACL; thus, it is important to achieve a proper graft configuration, diameter, and length. To avoid reruptures, an optimal and reproducible hamstring autograft is desired. Hamstring autograft has been traditionally devalued when compared with other options such as bone-patellar tendon-bone autograft. The purpose of this Technical Note is to describe in detail a hamstring braid graft configuration that could potentially overcome the past disadvantages of ACL reconstruction.

Biomechanical and geometric characterization of peroneus longus allografts with respect to age

BACKGROUND

Anterior cruciate ligament injuries are among the most common injuries in high impact sports, and reconstruction is the standard surgical procedure for these ruptures. Reconstructions are often performed using allografts rather than autografts on a case-by-case basis. Controversy exists as to whether or not age of donor tissue plays a factor in the mechanical properties of allografts.

METHODS

38 peroneus longus (PL) tendons were prepared using the two-strand graft technique and then subjected to a cyclic loading test regimen of 1000 cycles to determine material properties. Specimens were grouped based on age to ascertain whether donor age affects the material properties of PL tendons.

FINDINGS

Secant modulus of the first cycle was determined to be 150.43 (SD 40.24) MPa. The average magnitude of the dynamic modulus was determined to be 82.81 (SD 24.65) MPa. Specimens were grouped into three distinct groups for analysis (x < 40 yo, 40 yo ≤ x < 60 yo, 60 yo < x).

INTERPRETATION

The need for using intrinsic material properties is highlighted. There is no significant difference in any intrinsic material property with respect to age or the fatigue of the tendon as the cycle count increases. Conversely, the measured stiffness of a tendon decreased as function of age with a large effect size. Based on analysis of graft geometries, it was determined that PL tendons become significantly more slender with increased age which result in the observed decrease in stiffness.

Cells, soluble factors and matrix harmonically play the concert of allograft integration

Implantation of allograft tissues has massively grown over the last years, especially in the fields related to sports medicine. Beside the fact that often no autograft option exists, autograft related disadvantages as donor-site morbidity and prolonged operative time are drastically reduced with allograft tissues. Despite the well documented clinical success for bone allograft procedures, advances in tissue engineering raised the interest in meniscus, osteochondral and ligament/tendon allografts. Notably, their overall success rates are constantly higher than 80%, making them a valuable treatment option in orthopaedics, especially in knee surgery. Complications reported for allografting procedures are a small risk of disease transmission, immunologic rejection, and decreased biologic incorporation together with nonunion at the graft-host juncture and, rarely, massive allograft resorption. Although allografting is a successful procedure, improved techniques and biological knowledge to limit these pitfalls and maximize graft incorporation are needed. A basic understanding of the biologic processes that affect the donor-host interactions and eventual incorporation and remodelling of various allograft tissues is a fundamental prerequisite for their successful clinical use. Further, the importance of the interaction of immunologic factors with the biologic processes involved in allograft incorporation has yet to be fully dissected. Finally, new tissue engineering techniques and use of adjunctive growth factors, cell based and focused gene therapies may improve the quality and uniformity of clinical outcomes. The aim of this review is to shed light on the biology of meniscus, osteochondral and ligament/tendon allograft incorporation and how collection and storage techniques may affect graft stability and embodiment.Level of evidence V.

A Biomechanical Comparison of Alternative Graft Preparations for All-Inside Anterior Cruciate Ligament Reconstruction

PURPOSE

To biomechanically compare alternative graft constructs for all-inside anterior cruciate ligament (ACL) reconstruction in the event that the semitendinosus harvested is too narrow or too short to make a graft larger than 8 mm.

METHODS

Bovine extensor tendons were used to make 6 different 9-mm-diameter grafts: traditional 4-strand, anastomosis 4-strand, 6-strand, 3-strand, button-fixation 4-strand, and loop-and-tack 4-strand grafts. The grafts were then subjected to cyclic biomechanical testing followed by failure loading. Force at 3 and 5 mm of displacement and ultimate force were recorded for all grafts.

RESULTS

Compared with the traditional 4-strand graft, the only graft that showed significant biomechanical differences during the cyclic phase of testing was the button-fixation 4-strand graft, which was characterized by lower force at 3 mm of displacement (74 ± 34 N vs 122 ± 13 N, P = .004) and 5 mm of displacement (122 ± 35 N vs 172 ± 3 N, P = .006). During failure loading, ultimate force was significantly lower for both the 6-strand graft (491 ± 186 N, P = .041) and button-fixation 4-strand graft (326 ± 27 N, P < .001) than for the traditional 4-strand graft (778 ± 176 N). All other grafts were equivalent for the parameters tested.

CONCLUSIONS

The anastomosis 4-strand, 3-strand, and loop-and-tack 4-strand grafts do not biomechanically differ in cyclic loading and ultimate force from traditional 4-strand grafts. This study supports the use of anastomosis 4-strand, 3-strand, or loop-and-tack 4-strand grafts in the event that a traditional all-inside 4-strand graft cannot be prepared from a harvested semitendinosus tendon in ACL reconstruction.

CLINICAL RELEVANCE

This study tests and describes alternatives to the traditional 4-strand semitendinosus autograft for all-inside ACL reconstruction in the event that the harvested tendon is not adequate.

Mechanical assessment of tripled hamstring tendon graft when using suspensory fixation for cruciate ligament reconstruction

BACKGROUND

Tripling semitendinosus tendon for ACL graft preparation facilitates creation of longer and thicker grafts. Our objective was to evaluate the mechanical difference between tripled tendon grafts, prepared by three methods, by comparing with quadrupled tendon graft.

METHODS

Bovine hind-foot hoof extensors were allocated to four groups. Group I had quadrupled graft construct. Tripled graft constructs were prepared by passing the tendon to the Endobutton CL loop and stitching the third strand to (i) the loop (in Group II) or (ii) to one strand(in Group III) or (iii)to loop and both tendon strands (in Group IV). The constructs were preloaded from 10 to 50 N at 0.1 Hz for 10 cycles, followed by 1000 cycles of sinusoidal loading between 50 and 250 N at a frequency of 0.5 Hz. The specimens were then subjected to load to failure test at the rate of 50 mm/min. Displacement with cyclic loading, load at failure and the mode of failure were noted.

RESULTS

The load at failure was 957 ± 23.30 N (Mean ± Standard Deviation) in Group I, 590.8 ± 24.40 N in Group II, 682.6 ± 59.28 N in Group III and 963.4 ± 21.72 N in Group IV. The displacement with cyclic loading was 1.13 ± 0.11 mm in Group I, 4.908 ± 0.55 mm in Group II, 1.822 ± 0.55 mm in Group III and 1. 126 ± .018 mm in Group IV. There was no significant difference between the Groups I and IV with respect to the load at failure and displacement (p > 0.05). The values were significantly different in Group II and Group III (p < 0.01), when compared to groups I and IV.

CONCLUSIONS

Tripled grafts have mechanical properties equivalent to quadrupled grafts only when the three strands are sutured together. Caution may be warranted when using suspensory fixation device with tripled tendons and the third strand must be securely attached to the loop of fixation device and to the other two strands.

Editorial Commentary: How to Increase Hamstring Tendon Graft Size for Anterior Cruciate Ligament Reconstruction

The concept of a five-strand hamstring tendon autograft for anterior cruciate ligament reconstruction is not new. The concept of a five-strand hamstring tendon autograft was largely ignored until recent studies showed higher failure and revision rates for hamstring ACL reconstructions performed with graft diameters less than 8 mm. In the majority of patients in the United Arab Emirates, four-strand hamstring tendon autografts result in a graft diameter between 6.5-7.5 mm. As a result, since 2006, I have completely abandoned using four-strand hamstring tendon autografts in favor of five-and six-stranded hamstring tendon autografts for ACL reconstructions. The key to performing five-or six-strand hamstring tendon autografts lies in the ability to triple the semitendinosus tendon and in the case of six-strand hamstring tendon grafts, the gracilis tendon. Although, five-and six-strand hamstring tendon autografts can increase the diameter of hamstring tendon ACL grafts, the question of whether these grafts will reduce failure and revision rates remains unanswered.