Change in Size of Hamstring Grafts During Preparation for ACL Reconstruction: Effect of Tension and Circumferential Compression on Graft Diameter

Vertebropexy as a semi-rigid ligamentous alternative to lumbar spinal fusion

PURPOSE

To develop ligamentous vertebral stabilization techniques ("vertebropexy") that can be used after microsurgical decompression (intact posterior structures) and midline decompression (removed posterior structures) and to elaborate their biomechanical characteristics.

METHODS

Fifteen spinal segments were biomechanically tested in a stepwise surgical decompression and ligamentous stabilization study. Stabilization was achieved with a gracilis or semitendinosus tendon allograft, which was attached to the spinous process (interspinous vertebropexy) or the laminae (interlaminar vertebropexy) in form of a loop. The specimens were tested (1) in the native state, after (2) microsurgical decompression, (3) interspinous vertebropexy, (4) midline decompression, and (5) interlaminar vertebropexy. In the intact state and after every surgical step, the segments were loaded in flexion-extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS) and axial rotation (AR).

RESULTS

Interspinous vertebropexy significantly reduced the range of motion (ROM) in all loading scenarios compared to microsurgical decompression: in FE by 70% (p < 0.001), in LS by 22% (p < 0.001), in LB by 8% (p < 0.001) in AS by 12% (p < 0.01) and in AR by 9% (p < 0.001). Interlaminar vertebropexy decreased ROM compared to midline decompression by 70% (p < 0.001) in FE, 18% (p < 0.001) in LS, 11% (p < 0.01) in LB, 7% (p < 0.01) in AS, and 4% (p < 0.01) in AR. Vertebral segment ROM was significantly smaller with the interspinous vertebropexy compared to the interlaminar vertebropexy for all loading scenarios except FE. Both techniques were able to reduce vertebral body segment ROM in FE, LS and LB beyond the native state.

CONCLUSION

Vertebropexy is a new concept of semi-rigid spinal stabilization based on ligamentous reinforcement of the spinal segment. It is able to reduce motion, especially in flexion-extension. Studies are needed to evaluate its clinical application.

Prediction of hamstring tendon autograft diameter using preoperative measurements with different cut-offs between genders

PURPOSE

Studies have suggested some predictors for hamstring tendon (HT) autograft diameter based on anthropometric factors and preoperative magnetic resonance imaging (MRI) with variable results. Some authors have attributed the variability to gender differences. This prospective cohort reports the sensitivity and specificity of anthropometric and MRI predictors in males and females separately to determine the difference.

METHODS

Forty-two eligible patients who underwent anterior cruciate ligament reconstruction (ACLR) and MRI in our center were included. ACLR was performed by the senior surgeon using a 4-stranded HT autograft for all patients. A blinded musculoskeletal radiologist measured the cross-sectional area (CSA) of gracilis and semitendinosus tendons using the free-hand region of interest tool for all patients. An orthopaedic resident (PGY4) collected anthropometric factors and measured intraoperative autograft diameter.

RESULTS

Mean intraoperative autograft diameter was 8.0 mm. Females had a significantly lower autograft diameter (7.4 vs. 8.2, P < 0.001), smaller gracilis (6.9 vs. 7.9, P = 0.003) and semitendinosus CSA (11.5 vs. 12.8, P = 0.014) compared to males. ROC curve analysis resulted different cut-off values with high sensitivity and specificity for semitendinosus and combined CSA regarding gender.

CONCLUSION

Based on the results of this study, CSA of either isolated or combined HTs on preoperative axial MRI, height, and weight are the strongest predictors of intraoperative autograft diameter. It is suggested to consider different cut-offs for males and females to have a better clinical guide for surgeons.

LEVEL OF EVIDENCE

Level II.

Application of the 3D-MRI on post-operative graft assessment in adolescent patients with ACL reconstruction: A minimal 2-year follow-up

Background

The purpose of the present study was to assess the prognostic morphological changes of the reconstructed hamstring auto-grafts by using reconstructed three-dimensional MRI (3D-MRI) in adolescent patients with ACLR.

Methods

22 adolescent patients (less than 17 years old) were retrospective included between January 1, 2018, and October 31, 2020, in our department. The patients were divided into 2 subgroups: subgroup A (<14 years old) and subgroup B (≥14 years old). 3D-MRI was used to detect the total cross-sectional area (TCA) and long-to-short axis (LSA) ratio of the reconstructed ACL graft at the proximal, mid-point, and distal regions. The minimal follow-up was 2 years.

Results

The averaged follow-up of subgroup A and B was 37.8 ± 5.6 and 37.6 ± 6.5 months, respectively. Comparing to the initial graft (ACLR operation), the TCA of reconstructed ACL was increased by 30.6% on average, and the TCAs at proximal, mid-point, and distal regions were increased by 56.4%, 50.0%, and 17.7%, respectively, inner-group comparisons showed that the TCAs of the 3 region in subgroup A were all increased at the follow-up (P = 0.002) (P < 0.001) (P < 0.001), however, only increased mid-point (P = 0.024) and distal TCAs (P < 0.001) were found in subgroup B. Comparing to the native ACL, the proximal LSA ratio in subgroup A was comparable, while it was lower in subgroup B than the native ACL (P = 0.004), the distal LSA ratios in the 2 subgroups were both lower than the native ACL (P = 0.004) (P = 0.006).

Conclusions

3D-MRI assessment can exactly identify the morphological changes of the graft in adolescent patients with ACLR, the TCA of the constructed ACL was increased compared to the initial graft, however, the LSA ratio was still lower than the native ACL. Younger adolescent patients may have a better potential on the ligamentization after ACLR than the older adolescent patients.

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

Purpose

Methods

Results

Conclusions

Clinical Relevance

Quadriceps Tendon Autograft in Pediatric ACL Reconstruction: Graft Dimensions and Prediction of Size on Preoperative MRI

Background

There is increased interest in quadriceps autograft anterior cruciate ligament (ACL) reconstruction in the pediatric population.

Purpose

To evaluate children and adolescents who underwent ACL reconstruction using a quadriceps autograft to determine the properties of the harvested graft and to assess the value of demographic, anthropometric, and magnetic resonance imaging (MRI) measurements in predicting the graft size preoperatively.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A retrospective database search was performed from January 2018 through October 2020 for patients undergoing ACL reconstruction. Patients <18 years old at the time of surgery in whom a quadriceps tendon autograft was used were selected. Demographic data and anthropometric measurements were recorded, and graft measurements were abstracted from the operative notes. Knee MRI scans were reviewed to measure the quadriceps tendon thickness on sagittal cuts. Graft length and diameter were then correlated with anthropometric and radiographic data.

Results

A total of 169 patients (98 male) were included in the final analysis, with a median age of 15 years (range, 9-17 years). A tendon length ≥65 mm was harvested in 159 (94%) patients. The final graft diameter was 8.4 ± 0.7 mm (mean ± SD; range, 7-11 mm). All patients had a graft diameter ≥7 mm, and 139 (82%) had a diameter ≥8 mm. Preconditioning decreased the graft diameter by a mean 0.67 ± 0.23 mm. Age (P = .04) and quadriceps thickness on MRI (P = .003) were significant predictors of the final graft diameter. An MRI sagittal thickness >6.7 mm was 97.4% sensitive for obtaining a graft ≥8 mm in diameter.

Conclusion

Our findings suggest that tendon-only quadriceps autograft is a reliable graft source in pediatric ACL reconstruction, yielding a graft diameter ≥8 mm in 82% of pediatric patients. Furthermore, preoperative MRI measurements can be reliably used to predict a graft of adequate diameter in children and adolescents undergoing ACL reconstruction, with a sagittal thickness >6.7 mm being highly predictive of a final graft size ≥8 mm.

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.

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.

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.

Correlation of intra-operative hamstring autograft size with pre-operative anthropometric and MRI measurements

The purpose of this study was to compare various pre-operative methods of estimating intra-operative hamstring autograft size. A retrospective review was completed on 74 patients who had an anterior cruciate ligament reconstruction performed using a quadruple-looped hamstring autograft from July 2007-April 2015 at a single institution. A positive correlation was observed between intra-operative graft size and pre-operative imaging using two methods of MRI measurements. Correlation existed between hamstring size and patient height and weight, but not age or BMI. Thus, pre-operative MRI and anthropometric measurements can be used to estimate intra-operative hamstring graft size.

Hamstring Autograft in ACL Reconstruction: A 13-Year Predictive Analysis of Anthropometric Factors and Surgeon Trends Relating to Graft Size

Background:

Small-diameter autograft hamstring grafts have been linked to graft failure after anterior cruciate ligament (ACL) reconstruction. The frequency of hamstring autografts that actually meet ideal size criteria remains unknown.

Purpose:

To examine a large cohort of patients to (1) evaluate sizing variability among a large cohort of surgeons and (2) identify patient factors most predictive of hamstring autograft size.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 1681 ACL reconstructions with hamstring autograft were analyzed as completed by 11 surgeons over a 13-year period. Patient demographics (age, height, weight, body mass index, sex) and intraoperative details (including graft diameter and strands) were extracted. Univariate and multivariate regression analyses were performed to correlate patient demographics with graft size and to develop a predictive model for hamstring graft size.

Results:

The mean height and weight of patients included in this study were 172.7 cm and 80.1 kg, respectively; 59% of patients were male. The mean diameters of hamstring autografts were 8.4 mm and 8.2 mm for the tibial and femoral ends of the graft, respectively. A total of 55.1% of grafts were ≤8 mm. Mixed-effects linear modeling revealed that height, weight, sex, and use of ≥5 strands correlated with graft size (P < .001), while age did not. The predictive multivariate model based on the statistically relevant factors demonstrated a moderate correlation (r = 0.39, R² = 0.150), illustrated a predictive equation, and proved height to be the greatest determinant of graft size.

Conclusion:

Marked variability in graft size distribution was found among surgeons, and more than half of all grafts did not reach the ideal size for hamstring autograft ACL reconstruction. A predictive equation including anthropometric factors may be able to provide the expected graft size. The risk of early graft failure may be mitigated with preoperative consideration of anthropometric factors—most importantly, height—in preparation for possible augmentation, additional strands, or alternative graft sources.

Simplifying Anterior Cruciate Ligament Graft Bone Plug Reconstructions: The "U" Trough Technique

This Technical Note discusses an anterior cruciate ligament graft preparation technique to simplify and ease graft visualization, insertion, and fixation. Our technique incorporates a 2-mm central trough in the bone plug of the graft to improve one's ability to efficiently identify and orient the anterior cruciate ligament graft during insertion, and ensure correct screw placement and fixation.

Lateral Radiographic Landmarks for ACL and LCL Footprint Origins During All-Epiphyseal Femoral Drilling in Skeletally Immature Knees

BACKGROUND

This study was conducted to evaluate the spatial relationship of the anterior cruciate ligament (ACL) and lateral collateral ligament (LCL) femoral footprint origins in knee specimens from skeletally immature donors as viewed on lateral radiographs.

METHODS

Fourteen cadaver specimens of skeletally immature knees from children between 7 and 11 years old at the time of death were examined through gross dissection. Metallic pins were placed at the center of the ACL and LCL femoral footprints, and computed tomography (CT) scans were performed. Sagittal plane CT images were merged to create a view analogous to an intraoperative C-arm image with overlaid ACL and LCL ligament footprints. Ligament origins were then measured as a percent of the epiphyseal depth (% P-A [posterior-anterior]) and height (% P-D [proximal-distal]).

RESULTS

The ACL origin was centered at a point located 14% (14% P-A) of the total lateral femoral condyle (LFC) depth from the most posterior aspect of the LFC and 38% (38% P-D) of the LFC height from the most proximal aspect of the posterior physis. The LCL origin was centered at a point 27% P-A and 37% P-D. When viewed on a sagittal CT reconstruction analogous to a perfect lateral intraoperative fluoroscopic view, the ACL footprint origin is posterior and slightly inferior to the LCL origin. Both origins are distal to the distal femoral physis and are posterior to the origin of the popliteus.

CONCLUSIONS

This study demonstrates a consistent relationship between the origin of the ACL and LCL, which may be useful in guiding safe tunnel placement during all-epiphyseal ACL reconstruction in skeletally immature knees.

CLINICAL RELEVANCE

This anatomic reference can be used intraoperatively to guide and radiographically evaluate ACL tunnel placement while avoiding the LCL origin in skeletally immature patients.

Regression modelling combining MRI measurements and patient anthropometry for patient screening and prediction of graft diameter in hamstring autograft arthroscopic ACL reconstruction

Background

Previous studies have associated anthropometric data and pre-operative hamstring tendon measurements to intraoperative graft diameter for hamstring autograft ACL reconstruction, although an integrated model has yet to be described. The aim of this study was to present such a predictive model for quadrupled semitendinosus (4-ST) and doubled semitendinosus-gracilis (4-STG) graft constructs combining anthropometry (height and weight) and preoperative measurements of tendon as predictors.

Methods

ACL reconstructions using 4-STG and 4-ST were retrospectively reviewed. The outlines of the semitendinosus and gracilis tendons were identified manually in the axial slice of a preoperative T2 weighted MRI using a region-of-interest tool. Regression analysis using intraoperative graft diameter as the dependent variable was performed with tendon cross-sectional area (XSA), gender and height as predictors.

Results

108 ACL reconstructions in 107 patients were examined, 75 of which were performed using the 4-STG construct, and 33 which employed the 4-ST construct. The mean graft diameter in the 4-ST group (8.6 ± 0.8 mm) was significantly (p < 0.001) greater than the 4-STG group (7.9 ± 0.7 mm). Female gender and 4-STG graft construct were associated with increased risk of graft diameter <8 mm. Predictive models of graft diameter were accurate to ±1 mm for both construct types.

Conclusions

An integrated method for assessing patient risk of producing a diminutive graft diameter and planning augmentation in select cases has been presented. The present findings describe a validated predictive model that builds on previous univariable analyses. Further investigation of larger samples, including factors associated with graft preparation, is required to improve model accuracy for routine clinical application.

Level of evidence

IV, Retrospective Cohort Study

The 8-Strand Hamstring Autograft in Anterior Cruciate Ligament Reconstruction

Growing participation in youth athletics has resulted in increased numbers of anterior cruciate ligament (ACL) injuries in skeletally immature patients. Use of autogenous graft material has been associated with improved graft survival. However, pediatric patients sometimes possess hamstring tendons that produce smaller-diameter grafts than those prepared with adult autogenous materials. Smaller-diameter grafts may predispose younger patients to graft failure. We describe a technique that increases the diameter of the ACL construct through the use of an 8-strand autologous hamstring tendon graft. The 8-strand ACL autograft is commonly used in all-inside ACL reconstruction surgery.

Kinematic outcomes following ACL reconstruction

Anterior cruciate ligament (ACL) reconstruction aims to restore the translational and rotational motion to the knee joint that is lost after injury. However, despite technical advancements, clinical outcomes are less than ideal, particularly in return to previous activity level. A major issue is the inability to standardize treatment protocols due to variations in materials and approaches used to accomplish ACL reconstruction. These include surgical techniques such as the transtibial and anteromedial portal methods that are currently under use and the wide availability of graft types that will be used to reconstruct the ACL. In addition, concomitant soft tissue injuries to the menisci and capsule are frequently present after ACL injury and, if left unaddressed, can lead to persistent instability even after the ACL has been reconstructed. Advances in the field of biomechanics that help to objectively measure motion of the knee joint may provide more precise data than current subjective clinical measurements. These technologies include extra-articular motion capture systems that measure the movement of the tibia in relation to the femur. With data gathered from these devices, a threshold for satisfactory knee stability may be established in order to correctly identify a successful reconstruction following ACL injury.