Five-Strand Hamstring Autograft Versus Quadruple Hamstring Autograft With Graft Diameters 8.0 Millimeters or More in Anterior Cruciate Ligament Reconstruction: Clinical Outcomes With a Minimum 2-Year Follow-Up

The effectiveness of quadrupled semitendinosus graft technique in anterior cruciate ligament reconstruction: A network meta-analysis assessing various graft preparation techniques

PURPOSE

This study aims to perform a network meta-analysis of hamstring graft preparation techniques to enhance anterior cruciate ligament (ACL) reconstruction guidelines and inform clinical decision-making in patients with primary ACL rupture.

METHODS

A review of the literature, from 1 January 1990, to 31 August 2023, was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, focusing on the clinical outcomes of various hamstring graft preparation techniques. Forty-six studies (over 4800 knees) were analysed. Eight graft compositions: doubled hamstring (ST/G)-1978 grafts, doubled hamstring with augmentation (ST/G+A)-586 grafts, tripled semitendinosus (3ST)-124 grafts, quadrupled semitendinosus (4ST)-1273 grafts, five-strand tripled semitendinosus + doubled gracilis (3ST/2GR-839 grafts, six-strand tripled semitendinosus + tripled gracilis (3ST/3GR)-335 grafts, seven-strand quadrupled semitendinosus + tripled gracilis (4ST/3GR)-11 grafts and ≥eight strands-24 grafts were compared, considering graft sizes, laxity, muscle strength, range-of-motion, patient-reported outcome measures (PROMs), return to sport (RTS) and adverse events.

RESULTS

The 4ST grafts fared better than the ST/G grafts in the International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS) Sport, KOOS Q and RTS (mean difference [MD], -1.69; p = 0.0159; MD, -1.55; p = 0.0325; MD, -1.93; p = 0.001; odds ratio: 3.13; p < 0.0001). The IKDC differed significantly between the 4ST and ST/G+A groups (MD, 1.88; p = 0.046). The ST/G+A resulted in the lowest knee laxity, surpassing the ST/G, 3ST and 4ST. The ST/G had the smallest diameter (ST/G vs. ST/G+A: MD, 1.26; 95% confidence interval [CI]: 0.67-1.86, p < 0.0001). Reduced failure rates were noted with the 3ST/2GR (3ST/2GR vs. ST/G: MD, 6.93; p = 0.009) and 3ST/3GR (3ST/3GR vs. ST/G: MD, 53.64; p = 0.006).

CONCLUSION

The ideal hamstring graft for ACLR should be individualized. A 4ST graft is likely to yield good PROMs. For high stability and rapid RTS, adding augmentation to the graft is advisable. The ST/G is the thinnest graft possible.

LEVEL OF EVIDENCE

Network meta-analysis of level I-III studies.

The Influence of Different Hamstrings Assemblies on the Final Graft Diameter in Anterior Cruciate Ligament Reconstruction

Objective  This study aimed to compare gracilis and semitendinosus tendon graft diameters in anterior cruciate ligament (ACL) reconstruction using quadruple, quintuple, and sextuple assemblies. Another objective was to evaluate the percentage of patients in which each assembly type is possible, depending on the length of each free tendon. Methods  Seventy-one patients underwent ACL reconstruction using hamstring tendons. We measured the diameters of the quadruple, quintuple, and sextuple assemblies in all patients. We recorded tendon length and graft diameter from three assembly types. Results  Assembly comparison showed a statistically significant difference ( p  < 0.001). In each assembly, graft diameter increased by 1 mm, a statistically significant value ( p  < 0.001). In 2.8% of patients, the only potential assembly was the quadruple assembly because the free lengths of the 2 tendons removed were lower than 24 cm. The quintuple assembly was possible in 23.9% of subjects, as only the semitendinosus had a minimum length of 24 cm. The sextuple assembly was possible in 73.2% of patients because both tendons were at least 24 cm in length. Conclusion  A quintuple or sextuple assembly is possible in 97.2% of cases since the final graft length of at least 8 cm is statistically significant between comparisons.

Contralateral hamstring autografts do not provide benefit compared to ipsilateral hamstring autografts in primary or revision anterior cruciate ligament reconstruction: a systematic review

PURPOSE

To evaluate the clinical outcomes of primary or revision ACL reconstruction (ACLR) after contralateral hamstring autografts versus ipsilateral hamstring autograft harvest.

METHODS

Three databases (MEDLINE, PubMed and EMBASE) were searched from inception to April 27th, 2023 for studies investigating contralateral hamstring autografts in primary or revision ACLR. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, strength measures, patient-reported outcome measures (PROMs), and rates of positive Lachman test, positive pivot-shift test and graft rupture were extracted. PROMs included Lysholm, International Knee Documentation Committee (IKDC) and Tegner scores.

RESULTS

Nine studies comprising 371 patients were included in this review. In primary ACLR, there were no significant differences between contralateral and ipsilateral groups in isokinetic hamstring torque in the non-ACLR limb or isokinetic quadriceps torque in both limbs when tested at 60, 90, 120 or 180 degrees/second. Isokinetic hamstring torque in the non-ACLR limb was significantly weaker in the contralateral group at six months for primary ACLR; however, these deficits did not persist. There were no significant differences in postoperative median Tegner scores and Lysholm scores between contralateral and ipsilateral groups in primary ACLR. There were no significant differences in postoperative median Tegner, mean Lysholm and IKDC scores between groups in revision ACLR. There were no significant differences in positive Lachman, positive pivot-shift and rupture rates in primary ACLR between groups. Rates of positive Lachman and pivot-shift were slightly higher in the contralateral than ipsilateral group for revision ACLR.

CONCLUSION

Contralateral hamstring autografts results in comparable muscle strength to ipsilateral hamstring autografts, with the exception of weaker hamstring strengths in the early postoperative period. Patient-reported outcome measures were similar between the two groups across both primary and revision ACLR, with rates of instability and failure being similar between groups for primary ACLR. Contralateral hamstring grafts do not provide additional benefit when compared to ipsilateral options for either primary or revision ACLR, and should be used only in select circumstances including insufficient ipsilateral hamstring grafts or situations where quadriceps or patella autografts are not optimal.

LEVEL OF EVIDENCE

Level IV.

Estimated diameter increase from a 4S to a 6S hamstring graft configuration - A cadaveric study

PURPOSE

Graft diameter in anterior cruciate ligament reconstructions has been shown to influence the risk of failure. It is therefore important to be able to adjust the graft configuration to modify the diameter. To measure the impact of a 6-strand (6S) hamstring autograft configuration on graft diameter compared to the standard 4-strand (4S) configuration.

METHODS

Cadaveric study on 33 knees, using the usual hamstring graft harvesting technique. Semitendinosus and gracilis tendons were harvested and their length, width, and diameter were measured in 4S and 6S configurations separately by three evaluators.

RESULTS

6S configuration leads to a median increase of 1.5 (range: 0.0-2.0) mm in diameter compared to 4S (p < 0.001). A graft diameter of more than 8 mm is attained in less than a third of 4S grafts within this population in comparison to 84% when the 6S configuration is used.

DISCUSSION

The 6S hamstring graft configuration increases the graft diameter by a median of 1.5 millimeters compared to the traditional 4S configuration. It can reliably be used to obtain an 8.5 mm graft diameter or more in cases where the semitendinosus measures at least 270.5 mm and the 4S configuration has a diameter of 7.5 mm or 8 mm. This information helps to better delineate the impact of a 6S configuration in a pre-operative or intra-operative setting to optimize the decisional process and surgical flow and to easily adapt the graft diameter.

LEVEL OF EVIDENCE

V (cadaveric study).

No Deficits in Functional Outcomes of the Contralateral Limb Are Seen When the Hamstring Is Harvested for Augmentation of Small Diameter Ipsilateral Hamstring Autograft

Purpose

To evaluate clinical outcomes of the contralateral, nonoperative limb in patients undergoing contralateral hamstring (HS) autograft harvest compared with patients undergoing ipsilateral HS autograft harvest alone.

Methods

This study included 96 patients who underwent isolated anterior cruciate ligament reconstruction (ACLR) using 4-stranded HS autograft (n = 85) or 4-stranded HS autograft augmented with contralateral HS (n = 13) due to inclusion of ipsilateral graft diameter <8 mm. Isokinetic flexion and extension strength and dynamic performance of the ipsilateral and contralateral limbs and limb symmetry index (LSI) were evaluated at 6 months' postoperatively. Rates of contralateral native ACL tear at minimum 2 years also were compared. For all comparisons, P < .05 was considered statistically significant.

Results

Normalized isokinetic knee flexion and extension strength of the contralateral limb did not differ between cohorts (P = .34; P = .21, respectively). LSI for knee extension peak torque and knee flexion peak torque did not differ between cohorts (P = .44; P = .67, respectively). No difference in LSI was seen for any dynamic performance testing (single leg hop, P = .97; triple leg hop, P = .14; 6-m timed hop, P = .99). No difference was observed in International Knee Documentation Committee (P = .99) or Knee Injury and Osteoarthritis Outcome Score subscale measures (P = .39-.86). No difference in rates of contralateral knee native ACL tears were seen between cohorts (HS autograft + contralateral HS augmentation, n = 2, 15.4%; HS autograft, n = 7, 8.4%; P = .26).

Conclusions

In this study, at the time of return to sport, we found no differences in contralateral limb functional performance or limb symmetry measurements between patients undergoing contralateral HS autograft harvest for augmentation of smaller (<8 mm) diameter HS autografts harvested from the injured extremity.

Level of Evidence

Level III, retrospective cohort study.

Mid-Term Outcomes of the All-Soft Quadriceps Tendon Autograft Are Noninferior to Hamstring Autograft in Primary Anterior Cruciate Ligament Reconstruction: Comparison With Minimum 5-Year Follow-Up

PURPOSE

To compare the 5-year clinical and functional outcomes of the soft-tissue quadriceps tendon (QT) with those of the hamstring tendon (HT) autograft.

METHODS

A retrospective review of patients undergoing anterior cruciate ligament reconstruction using either soft-tissue QT or double-tendon HT autograft with at least 5 years of follow-up was conducted. Surgical technique included anteromedial portal creation for the femoral tunnel and transtibial technique for the tibia. Graft fixation was achieved with interference composite screws for the QT and combination of interference composite screw and suture button for the HT cohort. The 2 groups were compared for differences in outcomes, including International Knee Documentation Committee (IKDC) score, Lysholm score, return to sport, and complications.

RESULTS

A total of 37 patients with QT autograft and 46 HT autografts were included in the study, with a mean follow up of 69.9 months and 70.9 months, respectively. The QT group demonstrated a larger graft size on average (9.64 mm vs 7.90 mm, P < .001). The IKDC and Lysholm scores were similar between the 2 groups at 2-years' postoperatively. At 5 years' postoperatively, the QT group demonstrated significantly greater IKDC (P = .018) and Lysholm (P = .007) scores. The cohorts demonstrated similar rates of achieving minimal clinically important difference thresholds at both 2 and 5 years' postoperatively. The 2 groups also demonstrated comparable rates of return to sport, time to return, and postoperative complications.

CONCLUSIONS

Although the QT autograft demonstrated increased patient-reported outcome scores when compared with the HT at 5 years' postoperatively, there was no clinically significant difference between the cohorts at 2 or 5 years' postoperatively. The QT autograft is an effective alternative to HT autograft with noninferior results to the HT autograft at mid-term follow-up.

LEVEL OF EVIDENCE

III, retrospective comparison study.

No Difference Could Be Detected in Clinical Outcomes of 5-Strand and Quadruple Hamstring Autografts of Similar Diameter in Anterior Cruciate Ligament Reconstruction: A Retrospective Cohort Study

Background: There are few studies examining the clinical outcomes of 5-strand autografts in anterior cruciate ligament reconstruction (ACL-R). Purpose: We aimed to compare the clinical outcomes of ACL-R using 5-strand (5HS) and 4-strand (4HS) hamstring autografts of similar graft diameter to study the potential effects of autograft strand number on clinical outcomes. Methods: Patients who underwent ACL-R from 2013 to 2018 at a single academic institution and received a 4HS or 5HS autograft were included. Exclusion criteria were less than 2-year follow-up and any additional ligamentous reconstruction. Revision ACL-R and cyclops lesions were assessed at a minimum 2 years of postoperative follow-up. Objective measures of ability to return to sport were assessed at 6 months. Results: The mean graft diameters for 4HS (n = 51) and 5HS (n = 23) autografts were 8.3 ± 0.7 mm and 8.4 ± 0.7 mm, respectively. The mean follow-up for the 4HS and 5HS cohorts was 3.0 ± 1.5 years and 3.3 ± 1.3 years, respectively. The 4HS and 5HS cohorts had revision ACL-R rates of 15.7% (8/51) and 8.7% (2/23), respectively. Cyclops lesions occurred in 5.9% of 4HS patients and 13.0% of 5HS patients. We found no statistically significant differences between groups on objective measures of ability to return to sport. Conclusion: This retrospective cohort study detected no difference in revision ACL-R rates, frequency of cyclops lesions, or objective measures of ability to return to sport in patients who received 4HS or 5HS autografts of similar diameter for ACL-R. Further comparative study with larger sample sizes is warranted.

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

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.

Five-Strand Hamstring Grafts are Biomechanically Comparable to Four-Strand Grafts and Offer Greater Diameter for Anterior Cruciate Ligament Reconstruction

Purpose

The purpose of this study was to compare the biomechanics of 4-strand and 5-strand hamstring constructs for anterior cruciate ligament grafts.

Methods

Thirty-six human cadaveric hamstring grafts were tested in 3 different conditions: (1) graft femoral fixation complex, (2) graft femoral and tibial fixation (GFTF) complex using a human model, and (3) GFTF complex using a porcine model. Grafts were tested on a tensile testing machine. Four-stranded grafts served as the control group, and 5-stranded grafts served as the experimental group. Cyclic elongation, ultimate load to failure, stiffness, and diameter of the grafts were analyzed.

Results

Average 4-strand graft diameter was 7.96 mm compared to 9.32 mm for the 5-strand graft (P = .00017). Average stiffness of grafts ≥8 mm was 105.04 N/mm compared to 85.05 N/mm for grafts <8 mm (P = .04988). There was a positive correlation between graft diameter and stiffness (13.4 N/mm per every 1 mm increase in diameter, r² value of 13.1%, and F-significance of 0.02778). There were no significant differences in terms of ultimate load to failure, cyclic elongation, or stiffness between the experimental groups.

Conclusion

Five-strand hamstring grafts offer greater diameter and are biomechanically comparable to 4-strand equivalents at time 0. Grafts >8 mm offer significantly greater stiffness compared to grafts sized <8 mm. There is a weak positive correlation between graft diameter and stiffness.

Clinical Relevance

A potential drawback to hamstring grafts is their variability in size. Five-strand hamstring grafts provide increased diameter in comparison to 4-strand equivalents and might be used when quadrupled graft diameter is <8 mm.

Anterior Cruciate Ligament Sizing Tools Can Be Interchanged Without Affecting Graft Diameter Measurement

Purpose

Methods

Results

Conclusions

Clinical Relevance

Management of Intraoperative Graft-related Challenges in Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament reconstruction (ACLR) is one of the most frequently performed procedures in orthopaedic sports medicine. Intraoperative challenges related to graft procurement, graft preparation, and graft placement are common. Frequently encountered difficulties include insufficient graft diameter and graft-tunnel length mismatches, whereas less frequent challenges may be encountered during graft harvest and handling. This article discusses these possible complications and the strategies for their prevention and management. For successful ACLR, clinicians must be prepared to address each of these potential sources of difficulty.

Editorial Commentary: Addition of the Sartorius Tendon to Small-Diameter Hamstring Anterior Cruciate Ligament Autografts May Improve Outcomes in Pediatric and Revision Cases

Graft selection in anterior cruciate ligament reconstruction can have a pivotal role in a successful outcome. One of the major concerns with hamstring autograft is the variability of the diameter of each tendon, and grafts with a diameter of less than 8 mm may result in an increased failure rate. The addition of the sartorius tendon as a fifth strand in small-diameter hamstring autografts increases graft strength and diameter. This may improve outcomes in pediatric and revision cases.

Vancomycin Presoaking of Hamstring Autografts in Anterior Cruciate Ligament Reconstruction Is Associated With Higher Magnetic Resonance Imaging Graft Signal Without Influencing Clinical Outcome

PURPOSE

To present the clinical and imaging results of a series of patients undergoing anterior cruciate ligament reconstruction with vancomycin presoaking of the hamstring autograft compared with patients in the immediate period prior, when no vancomycin was used.

METHODS

This was a retrospective sequential series of patients with anterior cruciate ligament reconstruction using either a graft protocol with no vancomycin presoaking (group 1, January 2013 to October 2015) or a graft protocol with vancomycin presoaking (group 2, November 2015 to December 2018). Lysholm and International Knee Documentation Committee scores were obtained at a minimum 24-month follow-up. Graft ruptures were recorded. Between 6 and 12 months' follow-up, magnetic resonance imaging (MRI) was obtained to evaluate graft healing and integration.

RESULTS

There were 102 patients (72% male patients), with 40 in group 1 (mean age, 32.2 years) and 62 in group 2 (mean age, 32.3 years). A graft rupture occurred in 5 patients (13%) in group 1 and 6 patients (10%) in group 2 (P = .65). The median Lysholm score was 95 points (interquartile range [IQR], 86-100 points) in group 1 and 95 points (IQR, 90-100 points) in group 2 (P = .37). The median International Knee Documentation Committee score was 93 points (IQR, 82-99 points) in group 1 and 94 points (IQR, 86-99 points) in group 2 (P = .22). MRI evaluation of integration showed that 87 patients (90%) had no synovial fluid at the tunnel-graft interface, without a difference between groups (P = .24). On the basis of graft signal appearance, hyperintense grafts were found in 45 patients (46%); isointense, 45 (46%); and hypointense, 7 (7%). Group 1 had a higher prevalence of hypointense grafts, whereas group 2 had a higher prevalence of hyperintense and isointense grafts (P = .003).

CONCLUSIONS

Vancomycin presoaking of hamstring grafts increased the number of hyperintense and isointense grafts on MRI. Additionally, more hypointense grafts were noted when vancomycin was not used, suggesting the presence of more mature grafts in the non-vancomycin group.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The gracilis and semitendinosus muscles: a morphometric study on 18 specimens with clinical implications

INTRODUCTION

The pes anserinus consists of the sartorius, semitendinosus, and gracilis muscles. They coalesce together with the leg fascia to form the anserine plate. The semitendinosus and gracilis both form the deep layer of this plate and are clinically relevant for ligament reconstruction. The aim of the study is to report a detailed morphometric evaluation of the semitendinosus and gracilis muscles and assess their clinical implications.

METHODS

Using a rigorous dissection process on 18 cadaveric hips, measurements of both the semitendinosus and gracilis muscles with bone parameters were conducted. We measured the following: (a) total femur, femoral shaft, and neck lengths, (b) total muscle lengths, and (c) intra-muscular and extra-muscular (free) tendon lengths. Correlation values between bone variables, muscle variables, and in-between muscle variables were computed.

RESULTS

The total muscle and the distal intra-muscular tendon length of the St and Gr are correlated with the total femur length. When compared to gracilis, the total muscle and distal intra-muscular tendon lengths of the ST are much better correlated with the total femur length. The free distal tendon length for both muscles did not show a significant correlation with any of the femoral bone lengths.

CONCLUSION

The variability of tendon length of the ST/Gr poses a significant challenge to surgeons. This study reports a detailed morphometric evaluation of the ST/Gr hamstring muscle and tendons. It revealed a positive correlation between the femoral length and the ST/Gr graft lengths. This could help orthopedic surgeons in predicting the graft lengths pre-operatively and develop better planning for reconstructive surgeries.

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.

Anterior Cruciate Ligament Reconstruction Graft Technique Reliably Yields Grafts With 8.0-mm Diameter or Larger

The significance of graft diameter in anterior cruciate ligament reconstruction (ACLR) with soft tissue grafts is well established, with a minimum graft diameter of 8.0 mm associated with lower rates of revision surgery. Consistently achieving grafts that meet or exceed the ideal diameter of 8.0 mm is still a concern with traditional tibial screw fixation, even with quadrupled hamstring autografts. The authors hypothesized that following a simple intraoperative algorithm selectively incorporating the gracilis tendon in an 8-stranded construct for all-inside ACLR with suspensory fixation on both ends of the graft would consistently achieve graft diameters of 8.0 mm or larger by allowing more of the graft material to contribute to increased diameter instead of increased length for screw fixation, with no allograft tissue required. A total of 113 eligible cases were identified, including 70 male patients and 43 female patients (mean±SD age, 25.92±6.47 years; range, 14-49 years). All 113 grafts (100%) were at least 8.0 mm in diameter. There were 8 grafts that were 8.0 mm. Overall mean±SD graft diameter was 9.32±0.71 mm (median, 9.5 mm; range, 8.0-11.0 mm). There were no cases in which allograft tissue was needed to increase graft size. An analysis of 113 cases of all-inside hamstring autograft ACLR with dual suspensory fixation showed that a graft diameter of at least 8.0 mm was achieved in every case, without the use of allograft tissue. These results suggest that this technique for ACLR is reliable in producing grafts that meet or exceed the recommended minimum diameter of 8.0 mm. [Orthopedics. 2021;44(4):e539-e545.].

Reduction in Diameter of Hamstring Autograft With Additional Circumferential Preconditioning During ACL Reconstruction in a Pediatric Population

Background

Over 130,000 anterior cruciate ligament (ACL) reconstructions (ACLRs) are performed annually in the United States. Previous studies have shown that circumferential preconditioning reduces the diameter of fresh-frozen allografts, but no studies have described the effect in ACL autografts used during ACLR.

Purpose

To characterize the changes in the hamstring autograft diameter as a result of preparatory circumferential preconditioning.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 135 patients with ACLR, with a median age of 15 years (interquartile range, 14-16 years; 50.4% boys), were identified in 2 pediatric hospitals. Three orthopaedic surgeons recorded hamstring autograft diameters at 2 time points during graft preparation. Hamstring tendons were prepared using a standardized procedure, tensioned to 15 to 20 lbs, and measured using cylindrical sizing guides. The graft was left with passive compression in the smallest initial rigid sizing guide for 10 minutes on both the tibial and femoral sides and then measured again immediately before implantation. Tunnels were drilled based on the second measurement of graft size. Comparisons were made between the graft diameter before and after circumferential preconditioning. A random-effects regression model and a linear regression model were performed to capture any unexplained variance on the linear predictor scale and determine correlations between demographics and graft characteristics.

Results

The median initial diameter for both femoral and tibial sides was 9.5 mm. After longitudinal tension and circumferential preconditioning, the median autograft diameter of both sides decreased by 1 mm (P < .001) to 8.5 mm. In the random-effects model, decreased patient height was a significant predictor of greater reduction in graft diameter. Increased height was a significant predictor for greater initial graft diameter (average beta coefficient = 3.08; P < .01). No intraoperative complications were noted with implantation of the preconditioned grafts in smaller diameter tunnels.

Conclusion

The median diameter of hamstring ACL autografts decreases by 1 mm after circumferential preconditioning within standard cylindrical sizing guides. This allowed for drilling of tunnels that were an average of 1 mm smaller without any noted intraoperative complications with graft insertion.

Intraoperative Conversion to Five-Strand Hamstring Autograft Configuration Significantly Increases Anterior Cruciate Ligament Graft Diameter Independent of Patient Characteristics

Intraoperative conversion of a four-strand hamstring autograft to a five-strand configuration during an anterior cruciate ligament (ACL) reconstruction has been reported. However, the expected change in graft size and the dependence on patient characteristics are currently not well described. The purpose of this study was to determine the effective change in hamstring graft diameter and reliance on patient characteristics when intraoperatively converting a four-strand hamstring autograft into a five-strand configuration during an ACL reconstruction. A prospective, paired cohort study design was used to measure individual hamstring autograft diameter intraoperatively using traditional four-strand configuration followed by a five-strand configuration. All hamstring tendons included were long enough to consider a five-strand configuration. Five-strand hamstring autograft increased graft diameter in all patients. Hamstring tendon graft diameter increased by an average of 0.99 mm (95% confidence interval [CI]: 0.84-1.11) in the five-strand configuration compared with the traditional four-strand configuration (mean: 7.8 mm). There was no significant difference in the average increase in graft diameter between males (1.04 mm) and females (0.92 mm) (p = 0.323). Eighty-three percent (95% CI: 57.8-95.6) of average graft diameters ≤ 8 mm in the four-strand configuration achieved an average graft diameter of >8 mm in the five-strand configuration, and 70% (95% CI: 35.4- 91.9) of four-strand configuration average diameters < 8 mm achieved an average graft diameter > 8.0 mm in the five-strand configuration. Five-strand hamstring autograft reliably increased intraoperative hamstring tendon autograft diameter, with an average of 1 mm, compared with traditional four-strand configuration. This increase in diameter is independent of sex and remained significant when controlling for age, laterality, body mass index, and semitendinosus length.

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

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.

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.

Editorial Commentary: Multiple-Strand Hamstring Autografts for Anterior Cruciate Ligament Reconstruction: If Graft Diameter Is at Least 8 Millimeters, Bigger May Not Be Better

Anterior cruciate ligament graft diameter is of concern to every orthopaedic surgeon who's ever performed an anterior cruciate ligament reconstruction. The current standard is to obtain a graft of at least 8 mm in diameter. The 5-bundle construct is an option to increase the graft diameter in the situation in which a smaller diameter 4-strand hamstring autograft is encountered. The question is whether bigger is better once one obtains an 8-mm diameter graft.

An Autograft for Anterior Cruciate Ligament Reconstruction Results in Better Biomechanical Performance and Tendon-Bone Incorporation Than Does a Hybrid Graft in a Rat Model

BACKGROUND

The biomechanical and tendon-bone incorporation properties of allograft-augmented hybrid grafts for anterior cruciate ligament (ACL) reconstruction compared with traditional autografts are unknown.

HYPOTHESIS

Using an autograft for ACL reconstruction yields better results on biomechanical testing, radiographic analysis, and histological evaluation versus using a hybrid graft.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 66 adult male Sprague Dawley rats underwent unilateral ACL reconstruction with an autograft (AT group; n = 33) or a hybrid graft (HB group; n = 33). The grafts used in both groups were harvested from the peroneus longus tendon and were fixed by suturing to the surrounding periosteum. Samples were harvested for biomechanical testing, micro-computed tomography (CT), and histological evaluation at 4, 8, and 12 weeks postoperatively. Bone tunnels on the femoral and tibial sides were divided into 3 subregions: intra-articular (IA), midtunnel (MT), and extra-articular (EA). A cylinder-like volume of interest in the bone tunnel and a tubular-like volume of interest around the bone tunnel were used to evaluate new bone formation and bone remodeling, respectively, via micro-CT.

RESULTS

In the AT group, there were significantly higher failure loads and stiffness at 8 weeks (failure load: 3.04 ± 0.40 vs 2.09 ± 0.54 N, respectively; P = .006) (stiffness: 3.43 ± 0.56 vs 1.75 ± 0.52 N/mm, respectively; P < .001) and 12 weeks (failure load: 9.10 ± 1.13 vs 7.14 ± 0.94 N, respectively; P = .008) (stiffness: 4.45 ± 0.75 vs 3.36 ± 0.29 N/mm, respectively; P = .008) than in the HB group. With regard to new bone formation in the bone tunnel, in the AT group, the bone volume/total volume (BV/TV) was significantly higher than in the HB group on the tibial side at 8 weeks (IA: 22.21 ± 4.98 vs 5.16 ± 3.98, respectively; P < .001) (EA: 19.66 ± 7.19 vs 10.85 ± 2.16, respectively; P = .030) and 12 weeks (IA: 30.50 ± 5.04 vs 17.11 ± 7.31, respectively; P = .010) (MT: 21.15 ± 2.58 vs 15.55 ± 4.48, respectively; P = .041) (EA: 20.75 ± 3.87 vs 10.64 ± 3.94, respectively; P = .003). With regard to bone remodeling around the tunnel, the BV/TV was also significantly higher on the tibial side at 8 weeks (MT: 33.17 ± 8.05 vs 15.21 ± 7.60, respectively; P = .007) (EA: 25.19 ± 6.38 vs 13.94 ± 7.10, respectively; P = .030) and 12 weeks (IA: 69.46 ± 4.45 vs 47.80 ± 6.16, respectively; P < .001) (MT: 33.15 ± 3.88 vs 13.76 ± 4.07, respectively; P < .001) in the AT group than in the HB group. Sharpey-like fibers had formed at 8 weeks in the AT group. A large number of fibroblasts withdrew at 12 weeks. In the AT group, the width of the interface was significantly narrower at 4 weeks (85.86 ± 17.49 vs 182.97 ± 14.35 μm, respectively; P < .001), 8 weeks (58.86 ± 10.99 vs 90.15 ± 11.53 μm, respectively; P = .002), and 12 weeks (42.70 ± 7.96 vs 67.29 ± 6.55 μm, respectively; P = .001) than in the HB group.

CONCLUSION

Using an autograft for ACL reconstruction may result in improved biomechanical properties and tendon-bone incorporation compared with a hybrid graft.

CLINICAL RELEVANCE

Augmenting small autografts with allograft tissue may result in decreased biomechanical performance and worse tendon-bone incorporation, increasing the risk of graft failure.

Hamstring Autograft Versus Hybrid Graft for Anterior Cruciate Ligament Reconstruction: A Systematic Review

BACKGROUND

Hamstring tendon autografts are commonly used for primary anterior cruciate ligament (ACL) reconstruction. Some patients have small hamstring tendons however, which may compromise the clinical outcome of the autograft. To solve this problem, many surgeons use hybrid grafting that involves augmentation of small hamstring autografts with allograft tissue.

PURPOSE/HYPOTHESIS

The purpose was to compare the clinical outcomes between primary ACL reconstructions performed with hamstring autografts and those performed with hybrid grafts in terms of patient-reported evaluation, failure rate, and knee stability. The hypothesis was that primary ACL reconstruction performed with hamstring autograft alone will not differ significantly from that performed with a hybrid graft in terms of patient-reported evaluation, failure rate, or knee stability.

STUDY DESIGN

Systematic review.

METHODS

A systematic review was performed to identify prospective and retrospective comparative studies and cohort studies (evidence levels 1-3) comparing outcomes of primary ACL reconstructions performed with hamstring autografting alone and hybrid grafting. Outcomes included patient-reported evaluation, failure rate, and knee stability.

RESULTS

Ten studies were included: 1 of level 2 and 9 of level 3. Collectively, they included 398 autografts and 341 hybrid grafts. Mean respective follow-up durations ranged from 24.0 to 69.6 months and from 24.0 to 70.8 months. Patient-reported evaluations, including Lysholm, Tegner, and subjective International Knee Documentation Committee scores, were reported in 8 of 10 studies. Failure rates were reported in all 10 studies. Results of knee stability examinations-including KT-1000 arthrometer measurements, the pivot-shift test, Lachman test, and overall International Knee Documentation Committee results-were reported in 4 of 10 studies. In this review, there were no statistically significant differences between autografts and hybrid grafts in terms of patient-reported evaluations, failure rates, or KT-1000 measurements.

CONCLUSION

In this systematic review, there was no significant difference in patient-reported evaluation or failure rate between primary ACL reconstructions performed with autografts alone and those performed with hybrid grafts. Whether there is a substantial difference in knee stability examination results between autografts and hybrid grafts remains unknown, given a relative lack of reports on knee stability.

ACL hamstring grafts fixed using adjustable cortical suspension in both the femur and tibia demonstrate healing and integration on MRI at one year

PURPOSE

To present the clinical outcomes and magnetic resonance imaging (MRI) analysis of adjustable cortical suspensory fixation for the femur and tibia in hamstring autograft anterior cruciate ligament reconstruction.

METHODS

A cohort of 233 sequential patients was analysed for graft failure rate and subjective IKDC, Tegner and Lysholm scores. 144 validated 1-year MRIs assessed and correlated graft healing and tunnel widening.

RESULTS

At mean follow-up of 28 months ± 8.2 [median 26, range 12-49], the graft failure rate was 4.7%. Significant improvements were seen in all clinical scores (p < 0.001). MRI analysis showed 71% with fully integrated grafts in the tibia and 24% in the femur, with the remainder all showing greater than 50% integration. Graft signal was low and homogenous in 67% in the tibia, 29% in the intra-articular portion and 20% in the femur. One patient had greater than 50% high signal in the tibial graft and one in the intra-articular graft, all others demonstrated greater than 50% low signal. Both graft integration and signal were significantly better in the tibia than the femur (p < 0.01). Tunnel widening was 2.2 ± 1.4 mm and 2.7 ± 1.3 mm in the tibia and femur, respectively. Comparison of individual MRI appearances and overall clinical outcome at the same 12-month point demonstrated no consistent significant correlation.

CONCLUSION

Adjustable cortical suspensory fixation in both femoral and tibial tunnels provides good clinical outcomes and a low graft rupture rate. Grafts demonstrate healing with comparatively low tunnel widening. There was no consistent significant correlation between the appearances on MRI and clinical outcome.

LEVEL OF EVIDENCE

Case-control study, Level III.

Presoaking of Hamstring Autografts in Vancomycin Decreases the Occurrence of Infection Following Primary Anterior Cruciate Ligament Reconstruction

Background:

Postoperative septic arthritis is an uncommon but potentially devastating complication after anterior cruciate ligament (ACL) reconstruction. Our group started presoaking grafts with vancomycin to decrease this risk.

Purpose:

To compare the rate of septic arthritis in primary hamstring autograft ACL reconstruction with and without vancomycin-presoaked grafts.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Consecutive periods were studied, inclusive of April 2013 through October 2015 (pre-vancomycin protocol) and November 2015 through May 2018 (vancomycin protocol). A total of 490 patients were included in the study: 230 in the pre-vancomycin protocol and 260 in the vancomycin protocol. All patients who underwent a primary hamstring autograft ACL reconstruction by 2 senior surgeons during the periods studied were included. The final outcome studied was occurrence of highly probable postoperative septic arthritis in both groups. Diagnosis of probable septic arthritis was made by clinical diagnosis as well as cytological analysis of joint aspiration (cell count >50,000/μL and >90% neutrophils). Statistical analysis was performed with the Fisher exact test. Significance was set at P < .05.

Results:

Four cases of probable postoperative septic arthritis were noted in the pre-vancomycin protocol (1.7%; 2 cases per surgeon), while no cases of septic arthritis were noted in the vancomycin protocol during the study period (P < .05). Diagnosis was made at a mean 21.7 days (range, 16-25 days). Staphylococcus epidermidis was isolated in 2 cases, and in the other 2 cases, no organism was isolated.

Conclusion:

Presoaking of hamstring autografts in vancomycin for primary ACL reconstruction prevented the occurrence of postoperative septic arthritis during the study period as compared with no soaking of the grafts.

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.

Allograft Augmentation of Hamstring Anterior Cruciate Ligament Autografts Is Associated With Increased Graft Failure in Children and Adolescents

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction in adolescents is commonly performed with hamstring tendon autografts. Small graft diameter is one risk factor for graft failure and options to upsize the autologous hamstring graft include allograft augmentation and tripling one or both of the hamstring tendons.

PURPOSE

To evaluate the association of upsized hamstring graft constructs and graft rupture after ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review was performed of patients 19 years of age and younger who underwent hamstring autograft ACL reconstruction with or without soft tissue allograft augmentation from 2012 to 2016. All patients were skeletally mature or had less than 2 years of growth remaining. Graft constructs included 4-strand doubled semitendinosus and gracilis autograft (4-STG), 5-strand tripled semitendinosus and doubled gracilis autograft (5-STG), and 6-strand doubled gracilis and semitendinosus autograft augmented with a soft tissue allograft (6-STGAllo). The primary outcome measure was graft rupture.

RESULTS

A total of 354 patients with a mean age of 15.3 years (range, 10-19 years) were included. Graft constructs included 4-STG (198 knees), 5-STG (91 knees), and 6-STGAllo (65 knees). The average diameter of the graft constructs was 8.3 mm for 4-STG, 8.9 mm for 5-STG, and 9.2 mm for 6-STGAllo ( P < .001). The mean follow-up was 26 months (range, 6-56 months). There were 50 (14%) graft ruptures and 24 (7%) contralateral ACL tears. The graft failure rates were 14% for 4-STG, 12% for 5-STG, and 20% for 6-STGAllo ( P = .51). The average time to graft failure was 16 months (range, 2-40 months). After adjusting for age and graft size, patients who had allograft-augmented grafts (6-STGAllo) had 2.6 (95% CI, 1.02, 6.50) times the odds of graft rupture compared with 4-STG. There was no significant difference in failure rate between patients who had 5-STG grafts compared with 4-STG (OR, 1.2; 95% CI, 0.5, 2.7).

CONCLUSION

ACL reconstruction with hamstring tendon autografts augmented with allografts has a significantly increased risk of graft rupture compared with comparably sized hamstring tendon autografts. In situations where the surgeon harvests an inadequately sized 4-strand autograft, we recommend obtaining a larger graft diameter by tripling the semitendinosus rather than augmenting with an allograft.

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.

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

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.

No difference between full thickness and partial thickness quadriceps tendon autografts in anterior cruciate ligament reconstruction: a systematic review

PURPOSE

The purpose of this review was to compare outcomes and complication profiles of anterior cruciate ligament reconstruction (ACL-R) between full thickness (FT-Q) and partial thickness (PT-Q) quadriceps tendon (QT) autografts.

METHODS

As per PRISMA guidelines, PubMed, EMBASE, and MEDLINE were searched in September 2017 for English language, human studies of all levels of evidence on patients undergoing primary ACL-R with FT-Q or PT-Q. This search was repeated in March 2018 to capture additional articles. Data regarding postoperative outcomes and complications were abstracted. Due to heterogeneous reporting, data were not combined in meta-analysis and were summarized descriptively.

RESULTS

Upon screening 3670 titles, 18 studies satisfied inclusion/exclusion criteria. The second search identified an additional two studies for a total of 20 studies (50% case-control, 50% case series). These studies examined 1212 patients (1219 knees) of mean age 29.8 years (range 15-59) followed a mean of 42.2 months (range 12-120). FT-Q and PT-Q autografts were used in eight studies (50.5% of knees), and thirteen studies (49.5% of knees), respectively. Only one study directly compared FT-Q to PT-Q. Instrumented laxity was less than 3 mm in 74.8 and 72.4% of the FT-Q and PT-Q groups, respectively. Postoperative IKDC Subjective Knee Form scores were similar between the FT-Q (82.5) and PT-Q (82.1) groups. Postoperative quadriceps strength, measured as a percentage of the contralateral side, were similar in the FT-Q (89.5%) and PT-Q (85.1%) groups. Graft failure rates for the FT-Q and PT-Q groups were 3.7 and 3.0%, respectively.

CONCLUSION

Across the 20 studies included in this review, there appeared to be no difference in outcomes or complications between either FT-Q or PT-Q in primary ACL-R. Moreover, primary ACL-R using QT autografts appears to have successful outcomes with a low rate of graft failure, irrespective of tendon thickness. While further comparative studies are needed to better delineate the optimal thickness of quadriceps tendon for primary ACL-R, these data suggest that, in primary ACL-R, either FT-Q or PT-Q is efficacious and, in the clinical setting, surgeons may be justified in using either graft thickness.

LEVEL OF EVIDENCE

IV, Systematic Review of Level III and IV studies.

Knee kinematics in anatomic anterior cruciate ligament reconstruction with four- and five-strand hamstring tendon autografts

An alternative to the gold standard fourstrand hamstring tendon autograft for anterior cruciate ligament (ACL) reconstruction is the five-strand graft. The rationale for its use is to increase graft width to better restore the anatomical footprint and biomechanical properties of the native ACL when unable to create a four-strand graft of 8 mm in diameter. To date, there are no trials assessing the use of this wider graft and its effect on the kinematics of the knee. The aim of this study was to determine whether the use of a wider five-strand hamstring tendon autograft in ACL reconstructive surgery better replicated the kinematics of a normal non-injured knee than the gold standard four-strand graft. Forty-four patients (27 operative and 17 normal control) were recruited for this study over a 12-month period. Twenty patients underwent anterior cruciate ligament reconstruction with the four-strand hamstring tendon autograft construct and seven with the five-strand construct. All patients underwent kinematic testing using the KneeKG System (EMOVI, CA) according to a strict testing protocol. The operative group underwent testing at six (T1) and twelve (T2) weeks postoperatively. Analysis of variance was used to compare six degrees of freedom kinematic data across groups and correlations were made between kinematic data and intraoperatively measured graft width. Postoperative kinematic data revealed no statistically significant differences between graft types. At 12 weeks significant differences were seen between the four-strand and control group in the flexion/extension cycle in the preloading phase and at terminal stance. Significant correlations were seen between graft width and rotational stability at Preloading (Pearson’s r=0.415) and Maximum Internal Rotation (Femoral Width Pearson’s r=0.456 and Tibial Width Pearson’s r=0.476) at 12 weeks regardless of graft type.

This study demonstrated that to achieve anatomic knee kinematics in primary ACL reconstruction in the first 12 weeks postoperatively, a technique to optimise autograft width using a five-strand hamstring tendon autograft is useful. A relationship was found between graft width and more stable rotational kinematics of the knee during walking, regardless of graft type.

Use of the 5-Strand Hamstring Autograft Technique in Increasing Graft Size in Anterior Cruciate Ligament Reconstruction

BACKGROUND

To determine the extent to which a strategy of routinely preparing a 5-strand hamstring autograft would increase graft size in anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 64 patients were enrolled in a prospective randomized controlled study comparing 5-strand and quadrupled semitendinosus-gracilis autografts in single-bundle ACL reconstruction (5-strand group, n = 32; 4-strand group, n = 32). In the 5-strand group, the diameter of the 4-strand construct and the subsequent 5-strand graft used were measured, whereas in the 4-strand group, the diameter of the quadrupled graft used was measured. Quadrupled graft diameter and hamstring tendon lengths were correlated with patient gender, height, weight, and body mass index (BMI).

RESULTS

The mean diameter of the final graft used in the 5-strand group was 8.8 ± 0.8 mm, whereas that in the 4-strand group was 7.8 ± 0.7 mm (P < .001). The mean increase in graft size achieved with the use of the 5-strand technique was 1.4 ± 0.3 mm. In the 5-strand group, 24 of 32 (75%) patients had graft diameters exceeding 8 mm compared with 9 of 32 (28%) patients in the 4-strand group (P < .001). Quadrupled graft diameter was significantly correlated with patient height and BMI, whereas the gracilis and semitendinosus lengths were significantly correlated with patient height.

CONCLUSIONS

The 5-strand hamstring autograft provides a significantly larger diameter graft compared with the quadrupled hamstring autograft in ACL reconstruction. Graft sizes exceeding 8 mm are achievable in 75% of patients with the routine application of this technique. This is significantly more than that obtained with the standard quadrupled hamstring graft. Hamstring tendon length and quadrupled hamstring graft diameter are also significantly correlated with patient height.

LEVEL OF EVIDENCE

Level 1, prospective randomized controlled trial.

Estimating Lengths of Semitendinosus and Gracilis Tendons by Magnetic Resonance Imaging

PURPOSE

To determine whether preoperative magnetic resonance imaging (MRI) can help predict the tendon-only length of the semitendinosus (ST) and the gracilis (G).

METHODS

The distance from the tibial insertion to the distal-most aspect of the musculotendinous junction (MTJ) of the ST and G was estimated on preoperative MRI scans of patients undergoing primary anterior cruciate ligament (ACL) reconstruction with single-bundle, quadruple-stranded hamstring autograft. This MRI tendon-only length, measured by a musculoskeletal radiologist blinded to surgical findings, was compared to the actual tendon-only length measured upon harvesting each tendon.

RESULTS

Among the 42 patients comprising the study population, there was very strong correlation between the estimates of tendon-only length made by MRI and surgical measurements for both the ST (Spearman coefficient = 0.83; P < .0001) and the G (Spearman coefficient = 0.82; P < .0001). The difference between MRI and surgical measurements did not exceed 3 cm for any of the 84 harvested hamstring tendons. Bland-Altman plots confirmed agreement between the 2 measurement methods. There was also strong correlation between the surgically measured tendon-only length of the ST and its G counterpart (Spearman coefficient = 0.68; P < .0001).

CONCLUSIONS

MRI estimates of tendon-only length for both the ST and G very strongly correlate with operative measurements of these lengths; the discrepancy between these 2 measurement methods was found to not exceed 3 cm when the MTJ of these tendons is visible on MRI scans.

LEVEL OF EVIDENCE

Level III, comparative study.

Hamstring autograft size importance in anterior cruciate ligament repair surgery

Graft size in hamstring autograft anterior cruciate ligament (ACL) surgery is an important factor directly related to failure. Most of the evidence in the field suggests that the size of the graft in hamstring autograft ACL reconstruction matters when the surgeon is trying to avoid failures.

The exact graft diameter needed to avoid failures is not absolutely clear and could depend on other factors, but newer studies suggest than even increases of 0.5 mm up to a graft size of 10 mm are beneficial for the patient. There is still no evidence to recommend the use of grafts > 10 mm.

Several methods – e.g. folding the graft in more strands – that are simple and reproducible have been published lately to address the problem of having an insufficient graft size when performing an ACL reconstruction. Due to the evidence presented, we think it is necessary for the surgeon to have them in his or her arsenal before performing an ACL reconstruction.

There are obviously other factors that should be considered, especially age. Therefore, a larger graft size should not be taken as the only goal in ACL reconstruction.

Cite this article: EFORT Open Rev 2018;3:93-97. DOI: 10.1302/2058-5241.3.170038

A 5-Strand Hamstring Autograft Achieves Outcomes Comparable to Those of a 4-Strand Hamstring Autograft With a Graft Diameter of 8 mm or More in Anterior Cruciate Ligament Reconstruction

Background:

Quadrupled (4-strand) hamstring tendon autografts are commonly used in anterior cruciate ligament (ACL) reconstruction, but there is significant variability in their diameter. The 5-strand hamstring autograft has been used as a means of increasing the graft diameter in patients with undersized hamstring grafts.

Purpose:

To report the outcomes of primary ACL reconstruction using 5-strand hamstring autografts in patients in whom the 4-strand configuration produced a graft diameter of <8 mm and to compare these outcomes with those of ACL reconstruction using 4-strand semitendinosus-gracilis autografts with a graft diameter of ≥8 mm.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

The primary study group comprised 25 patients who underwent ACL reconstruction using a 5-strand hamstring autograft. The comparison group comprised 20 patients who underwent ACL reconstruction using a 4-strand hamstring autograft with a graft diameter of ≥8 mm. Interference screw fixation was used at the tibial and femoral ends for both groups of patients. Subjective questionnaires, including the Knee injury and Osteoarthritis Outcome Score (KOOS), the Lysholm score, and the Physical Component Summary and Mental Component Summary of the Short Form–36 (SF-36), were administered preoperatively as well as at 1- and 2-year follow-up visits.

Results:

There were no significant differences in the patient demographics and preoperative scores between the 2 groups. The mean graft diameter was 9.06 ± 0.60 mm in the 5-strand group and 8.13 ± 0.32 mm in the 4-strand group (P < .05). There was no statistically significant difference between groups on postoperative Lysholm, KOOS Pain, KOOS Symptoms, KOOS Activities of Daily Living, KOOS Sports, KOOS Quality of Life, and SF-36 Physical Component Summary scores.

Conclusion:

In primary ACL reconstruction, the 5-strand hamstring autograft achieves clinical outcomes that are comparable to those of the 4-strand hamstring autograft with a graft diameter of ≥8 mm. The 5-strand graft technique is therefore a useful means of increasing the graft diameter when faced with an undersized hamstring graft.

Graft Preparation Technique to Optimize Hamstring Graft Diameter for Anterior Cruciate Ligament Reconstruction

Hamstring autografts are frequently used for anterior cruciate ligament reconstruction. The inherent variability in graft diameter has been stated as a disadvantage in its use because the presence of smaller graft diameters has been correlated with increased risk of re-rupture. Several techniques have been described to address this concern. Modifications of the basic Graftlink technique allows for increased control over final graft diameter using a standard harvest of the semitendinosus tendon with or without the gracilis tendon, and results in a graft of adequate length and diameter in all patients with rigid cortical fixation on the femur and tibia.

Editorial Commentary: Size Does Matter-Anterior Cruciate Ligament Graft Diameter Affects Biomechanical and Clinical Outcomes

Anterior cruciate ligament (ACL) graft strength is related to graft diameter and how ACL grafts heal. All grafts appear to lose strength during healing. Clinical studies have documented that hamstring grafts less than 8 mm wide are more vulnerable to failure. Tripling the semitendinosus allows to increase the graft diameter and strength. A recent study documents a semitendinosus tripling technique with excellent clinical results.