The Use of Suture Augmentation for Graft Protection in ACL Reconstruction: A Biomechanical Study in Porcine Knees

Analysis of Graft Types Augmented With an Internal Brace for ACL Reconstruction: A Systematic Review

BACKGROUND

New techniques are being developed to decrease the failure rate of anterior cruciate ligament (ACL) grafts and prevent revision surgery. One such technique involves high-strength suture tape (ST), also referred to as internal bracing. Recent literature has highlighted the use of ST for ACL reconstruction, but no study has compared ST augmentation between graft types.

PURPOSE

To compare the use of ST augmentation for ACL reconstruction based on the type of graft used (ie, bone-patellar tendon-bone [BPTB], quadriceps, hamstring).

STUDY DESIGN

Systematic review; Level of evidence, 5.

METHODS

An online search of multiple databases was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and was completed April 2022 to identify studies related to ST augmentation of ACL grafts.

RESULTS

Of 926 studies identified, 10 met inclusion criteria. Five studies (50%) used hamstring tendon (HT), 3 (30%) used quadriceps tendon (QT), 1 (10%) used BPTB, and 1 (10%) used both HT and QT grafts. HT autografts augmented with ST had decreased dynamic and peak elongation (15%-56%), increased load to failure, and increased initial and final dynamic stiffness compared with controls. There was no significant difference in postoperative physical examination findings (range of motion, Lachman, pivot shift), except that ST-augmented grafts had significantly less laxity after surgery compared with HT alone (0.8 vs 1.9 mm; P < .05). QT allografts with ST augmentation showed increased graft strength. Human QT autograft studies showed higher Knee injury and Osteoarthritis Outcome Score scores compared with controls. BPTB allografts with ST augmentation had decreased cyclic displacement by 31% (P = .015) and increased load (758 ± 128 N; P < .001) and stiffness (156 ± 23 N/mm; P = .003) compared with nonaugmented groups. The complication rate was low or showed no increase in the ST augmentation groups compared with control groups.

CONCLUSION

HT, QT, and BPTB grafts augmented with ST demonstrate an effective method for ACL reconstruction. All graft types with ST augmentation showed no evidence of clinical disadvantage, with some studies indicating significant biomechanical or clinical advantages compared with conventional ACL reconstruction.

Tailoring the pore design of embroidered structures by melt electrowriting to enhance the cell alignment in scaffold-based tendon reconstruction

Tissue engineering of ligaments and tendons aims to reproduce the complex and hierarchical tissue structure while meeting the biomechanical and biological requirements. For the first time, the additive manufacturing methods of embroidery technology and melt electrowriting (MEW) were combined to mimic these properties closely. The mechanical benefits of embroidered structures were paired with a superficial micro-scale structure to provide a guide pattern for directional cell growth. An evaluation of several previously reported MEW fiber architectures was performed. The designs with the highest cell orientation of primary dermal fibroblasts were then applied to embroidery structures and subsequently evaluated using human adipose-derived stem cells (AT-MSC). The addition of MEW fibers resulted in the formation of a mechanically robust layer on the embroidered scaffolds, leading to composite structures with mechanical properties comparable to those of the anterior cruciate ligament. Furthermore, the combination of embroidered and MEW structures supports a higher cell orientation of AT-MSC compared to embroidered structures alone. Collagen coating further promoted cell attachment. Thus, these investigations provide a sound basis for the fabrication of heterogeneous and hierarchical synthetic tendon and ligament substitutes.

A comparative analysis of suture-augmented and standard hamstring autograft single-bundle ACL reconstruction outcomes: short-term functional benefits without long-term impact

BACKGROUND

Augmentation of the biologic graft with nonabsorbable suture material during anterior cruciate ligament reconstruction (ACLR) is a relatively new technique to enhance its biomechanical properties and add additional support to the critical process of healing. We aimed to compare the short-term functional patient-reported outcome measures (PROMs) and complication rates of patients treated with either standard single-bundle four-strand hamstring ACLR or added suture augmentation (SA).

METHODS

Patients undergoing arthroscopic ACLR between February 2015-January 2017 and in the standard ACLR group, and between February 2017-September 2019 in the SA-ACLR group operated by adding a no.5 FiberWire® (Arthrex, Naples, FL, USA) braided suture to the hamstring autograft, were retrospectively reviewed and the PROMs were compared. Patients were followed up for a 24-month period and PROMs were assessed by the International Knee Documentation Committee (IKDC) Subjective Knee Form and Tegner-Lysholm knee score. Patients' demographic and clinical characteristics, and postoperative complications including graft retear requiring revision surgery, deep vein thrombois, and surgical site infection were recorded and analyzed.

RESULTS

We included 79 patients with mean age of 31.6 ± 8.3 years in the standard ACLR group, and 90 patients with mean oge of 30.5 ± 7.6 in the SA-ACLR group. There was no statistically significant difference between the two groups in terms of age, sex, body mass index, and medical comorbidities. The values of the IKDC scores increased to 75.8 ± 18.9 in the standard ACLR group, and 85.6 ± 12.6 in the SA-ACLR group, 24 months after the operation (P < 0.05). The 24-month postoperative Tegner-Lysholm scores escalated to 79.3 ± 21.0 in the standard ACLR group and 91.0 ± 13.7 in the SA-ACLR group (P < 0.05). Four (5.1%) patients in the standard ACLR group and 4 (4.4%) in the SA-ACLR group experienced graft retear requiring revision surgery (P > 0.05). Incidence of surgical site infection and deep vein thrombosis showed no significant differences between the two groups, 24 months after ACLR.

CONCLUSION

SA-ACLR is associated with improved short-term functional PROMs compared to the standard hamstring ACLR. Although SA did not reduce the retear rate, and infection and DVT rates did not differ between study groups, superior improvement of PROMs in SA approach, leverages this method for ACLR.

Evaluation of biomechanical properties and biocompatibility: are partially absorbable cords eligible for anterior cruciate ligament reconstruction?

Introduction: Independent augmentation technology based on reinforcing devices has been reported to signifi-cantly reduce the elongation behavior of graft and improve knee stability after anterior cruciate ligament reconstruction (ACLR). Using biodegradable devices could reduce the risk of severe inflammatory reactions due to particle accumulation from foreign bodies. Given the limitations of the mechanical properties of biodegradable materials, partially biodegradable composite devices may offer a compromise strategy. Methods: Three types of partially absorbable core-sheath sutures, including low-absorbable cord (LA-C), medium-absorbable cord (MA-C) and high-absorbable cord (HA-C), were braided using unabsorbable ultra-high molecular weight polyethylene (UHMWPE) yarn and absorbable polydioxanone (PDO) monofil-ament bundle based on the desired configuration. The feasibility of these partially absorbable cords were verified by biomechanical testing, material degradation testing, and cell experiments, all performed in vitro. Results: Reinforcement of an 8 mm graft with the cords decreased dynamic elongation by 24%-76%, was positively related to dynamic stiffness, and increased the failure load by 44%-105%, during which LA-C showed maximum enhancement. Human ligament-derived fibroblasts showed good proliferation and vitality on each cord over 2 weeks and aligned themselves in the direction of the fibers, especially the UHMWPE portion. Discussion: This study supports the potential of partially degradable UHMWPE/PDO cords, particularly LA-C, for graft protection. Nervertheless, a higher proportion of biodegradable material results in lower stiffness, which may impair the protective and lead to mechanical instability during degradation.

Augmentation with Fibertape Leads to Biomechanically Superior but Similar Clinical Outcomes in ACL Surgeries: Systematic Review and Meta-analysis

Purpose

The current generation has witnessed significant progress in the field of knee arthroscopy. Suture tapes have gained immense popularity due to perceived improved biomechanical support to the graft while it heals. The purpose of the present systematic review is to analyze the biomechanical construct of suture tapes in ACL repairs and reconstructions along with clinical outcomes.

Methods

Cochrane Library, PubMed, and Embase were searched until December 2021. All Biomechanical Studies on animal or cadaver knees that compared construct characteristics of suture tape in ACL repair or reconstruction and clinical studies in English focusing on outcomes following suture tape augmentation in ACL repair or reconstruction were included. The quality of clinical studies using the Modified Coleman Methodology Score (MCMS).

Results

A total of 16 studies biomechanical and 23 clinical studies were included in qualitative synthesis, leaving nine biomechanical studies for final quantitative analyses. Suture tape revealed biomechanical superiority in terms of ultimate strength, stiffness, cyclic displacement, and elongation of graft, while comparing ACLR with internal brace to standard ACLR. No significant difference in retear rates was seen in clinical studies. Clinical score(IKDC score) was found similar in both augmented and non-augmented construct. Similar results were obtained in biomechanical studies.

Conclusion

The use of suture tape as a ligament augmentation in both ACL reconstruction and ACL repair offers more strength, less elongation or displacement, and is biomechanically stable and sound. There is a lack of data to comprehensively comment upon the clinical superiority of the use of internal augmentation. However, a meta-analysis of the retear rates and clinical outcome score revealed similar outcomes between suture tape augmented and nonaugmented groups.

Suture-tape augmentation of anterior cruciate ligament reconstruction: a prospective, randomised controlled trial (STACLR)

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction aims to restore anteroposterior and rotatory stability to the knee following ACL injury. This requires the graft to withstand the forces applied during the process of ligamentisation and the rehabilitative period. We hypothesise that the use of suture tape augmentation of single bundle ACL reconstruction (ACLR) will reduce residual knee laxity and improve patient-reported outcomes at 2-year follow-up. We will conduct a 1:1 parallel arm single-centre randomised controlled trial comparing suture tape augmented ACLR to standard ACLR technique.

METHODS

The study design will be a parallel arm 1:1 allocation ratio randomised controlled trial. Sixty-six patients aged 18 and over waitlisted for primary ACLR will be randomised. Patients requiring osteotomy and extra-articular tenodesis and who have had previous contralateral ACL rupture or repair of meniscal or cartilage pathology that modifies the post-operative rehabilitation will be excluded. The primary outcome measure will be the side-to-side difference in anterior tibial translation (measured on the GNRB arthrometer) at 24 months post-surgery. GNRB arthrometer measures will also be taken preoperatively, at 3 months and 12 months post-surgery. Secondary outcomes will include patient-reported outcome measures (PROMs) collected online, including quality of life, activity and readiness to return to sport, complication rates (return to theatre, graft failure and rates of sterile effusion), examination findings and return to sport outcomes. Participants will be seen preoperatively, at 6 weeks, 3 months, 12 months and 24 months post-surgery. Participants and those taking arthrometer measures will be blinded to allocation.

DISCUSSION

This will be the first randomised trial to investigate the effect of suture-tape augmentation of ACLR on either objective or subjective outcome measures. The use of suture-tape augmentation in ACLR has been associated with promising biomechanical and animal-level studies, exhibiting equivalent complication profiles to the standard technique, with initial non-comparative clinical studies establishing possible areas of advantage for the technique. The successful completion of this trial will allow for an improved understanding of the in situ validity of tape augmentation whilst potentially providing a further platform for surgical stabilisation of the ACL graft.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry ACTRN12621001162808. Universal Trial Number (UTN): U1111-1268-1487. Registered prospectively on 27 August 2021.

Clinical Research Progress of Internal Brace Ligament Augmentation Technique in Knee Ligament Injury Repair and Reconstruction: A Narrative Review

Knee ligament injuries are most common in sports injuries. In general, ligament repair or reconstruction is necessary to restore the stability of the knee joint and prevent secondary injuries. Despite advances in ligament repair and reconstruction techniques, a number of patients still experience re-rupture of the graft and suboptimal recovery of motor function. Since Dr. Mackay's introduction of the internal brace technique, there has been continuous research in recent years using the internal brace ligament augmentation technique for knee ligament repair or reconstruction, particularly in the repair or reconstruction of the anterior cruciate ligament. This technique focuses on increasing the strength of autologous or allograft tendon grafts through the use of braided ultra-high-molecular-weight polyethylene suture tapes to facilitate postoperative rehabilitation and avoid re-rupture or failure. The purpose of this review is to present detailed research progress in the internal brace ligament enhancement technique of knee ligament injury repair as well as the reconstruction from biomechanical and histological research and clinical studies and to comprehensively assess the value of the application of this technique.

All-inside arthroscopic anterior cruciate ligament reconstruction with internal brace Ligament Augmentation using semitendinosus tendon autograft: A case series

Introduction and importance

Anterior Cruciate Ligament (ACL) reconstruction surgery has been proven to be closely related to the graft healing process, which can last up to 12 months after surgery. In recent years, through various biomechanical and clinical studies, Internal Brace Ligament Augmentation (IBLA) has been shown to protect the graft during these early postoperative stages and improve the outcome of ACL reconstruction. We present this case series of all-inside arthroscopic anterior cruciate ligament reconstruction with IBLA using semitendinosus tendon autografts, with the goal of evaluating postoperative clinical and patient-reported outcomes.

Case presentation

A total of 37 patients who underwent all-inside arthroscopic anterior cruciate ligament reconstruction with IBLA using only semitendinosus tendon autografts, were evaluated, in terms of patient reported outcome and clinical assessment, during the 3, 6 and 12 months post-operative follow-up. Results: The mean Lysholm Knee score at the final follow-up was 94,03 +- 3,65 with a difference of 34,59 +- 5,52 to the baseline level. International Knee Documentation Committee (IKDC) classification rated 30 cases of grade A and 7 cases of grade B. In terms of clinical tests and knee's range of motion, all patients have returned to normal, and no cases of re-rupture or other severe complications were found.

Clinical discussion

Early follow-up patient reported outcomes have provided good to great results for the 37 patients who underwent all-inside arthroscopic anterior cruciate ligament reconstruction with IBLA using semitendinosus tendon autografts and no cases of graft failure or other notable complication has been discovered. Clinical findings suggest improved knee's integrity and range of movement during the early stages, which may promote early rehabilitation, however future long-term comparative studies are needed.

Conclusion

IBLA with all-inside ACL reconstructions using only semitendinosus autograft has provided good to great results however, future long-term comparative studies are needed.

Suture Tape Augmentation of Anterior Cruciate Ligament Reconstruction Increases Biomechanical Stability: A Scoping Review of Biomechanical, Animal, and Clinical Studies

PURPOSE

To (1) assess the available literature reporting on suture tape augmentation in anterior cruciate ligament (ACL) reconstruction and (2) determine what evidence exists to support and oppose the technique in clinical practice.

METHODS

Five databases were systematically searched on November 24, 2021, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Technical, animal, biomechanical, and clinical studies were included. Quality appraisal was conducted according to study type. Data were extracted and reported in tabular and narrative form according to the study design.

RESULTS

In total, 1276 studies were appraised, with 22 studies including 6 biomechanical, 3 animal, 10 technical, and 3 clinical studies. Biomechanical studies reported tape-augmented grafts to withstand 12.2% to 73.0% greater load to failure and 17.0% to 60.2% reduced elongation compared with standard ACL reconstruction. Evidence of load sharing started at 200 N (7-mm graft) and 300 N (9-mm graft), with suture tape augments taking 31% and 20% of the final load (400 N), respectively, in one study. Among animal studies, no significant differences in complications, rates of ligamentization, histologic findings, or evidence of stress shielding were reported. Technical studies differed primarily in the method of fixation of the proximal end of the tape. Clinically, patient-reported outcome measures were mixed among significant and nonsignificant improvements in International Knee Documentation Committee scores and return to sport among tape-augmented groups, with no difference in complications.

CONCLUSIONS

Biomechanically, suture tape augmentation of ACL reconstruction increased the strength of the graft complex and reduced elongation, with early evidence of the "safety belt" effect with load-sharing properties at greater loads established. In animal studies, graft maturation and 4-zone bone healing, and equivalent rates of intra-articular complications were detected in ACL reconstruction with suture tape augmentation. In clinical studies, patient-reported outcomes were mixed between improved and equivalent outcomes with and without suture tape augmentation, whereas graft failure was not adequately powered to be assessed.

CLINICAL RELEVANCE

Suture tape augmentation of ACL reconstruction offers a low-cost method of improving initial biomechanical stability of the ACL graft. Animal and clinical data suggest the complication profile associated with synthetic grafts may not be apparent in tape augmentation. Independent suture tape augmentation may be considered with aims to increase the initial stability of the native ACL graft.

Posterior cruciate ligament reconstruction with independent internal brace reinforcement: surgical technique and clinical outcomes with a minimum two year follow-up

PURPOSE

We developed an augmentation technique for PCL reconstruction with independent internal brace reinforcement and evaluated the functional outcome after PCL reconstruction employing autologous hamstrings augmented with an internal brace system for patients with isolated or combined grade 3 posterior instability who were treated with this technique.

METHODS

From January 2016 to January 2018, patients with isolated or combined grade 3 PCL tears who underwent single-bundle PCL reconstruction using autologous hamstrings augmented with independent internal braces were studied. The function of the operated knee was evaluated according to the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity score. The patients were asked the level of returned to their previous sport. Posterior knee laxity was examined with a KT-1000 arthrometer, and data on range of motion (ROM), re-operation, and other complications were collected.

RESULTS

A total of 33 consecutive patients who received single-bundle PCL reconstruction using autologous hamstrings augmented with independent internal braces with a minimum two years follow-up were included in this study. Two patients had undergone this procedure during the study period and were not included in this study (one had combined bone fractures, and one patient had previous meniscus surgery). Thirty-one patients were available for final analysis. The mean follow-up was 45.35 ± 10.88 months (range 29-66 months). The average IKDC subjective knee evaluation scores from 51.65 ± 12.35 to 84.52 ± 6.42, the Lysholm score from 53.90 ± 11.86 to 85.68 ± 4.99, and the Tegner score from 2.81 ± 0.79 to 6.71 ± 1.83 (P < 0.05 for all). The mean total posterior side-to-side difference in knee laxity, assessed using a KT-1000 arthrometer, decreased from 12.13 ± 2.66 mm pre-operatively to 1.87 ± 0.56 mm post-operatively at 70° (P < 0.05). Most patients (29/31) had normal or near normal knee ROM post-operatively; two patients revealed a 6-15° loss of knee flexion compared with the contralateral knee. Twenty-nine patients (93.55%) returned to a normal daily exercise level. Twenty-three patients (74.19%) returned to competitive sports with high-level sports (Tegner score of 6 or above; eleven patients (35.48%) reported to be on the same level as well as the Tegner level); six patients (19.35%) returned to recreational sports (Tegner score of 4 or 5). Two patients had Tegner scores of 2 and 3, indicating poor function level. No patient needed PCL revision surgery during the follow-up period.

CONCLUSION

Single-bundle PCL reconstruction with internal brace augmentation for PCL injury exhibited satisfactory posterior stability and clinical outcomes in patients with isolated or combined grade 3 PCL injuries at a minimum two year follow-up.

Ultimate Load Measuring System for Fixation of Soft Tissue to Bone

BACKGROUND

The initial ultimate load for graft fixation is one of the essential factors in the reconstruction of lateral ankle ligaments. Several anchoring devices have been developed to fix the substitute ligament into the bone. A fair comparison of these fixation methods warrant a reproducible examination system. The purpose of this study was to make an experimental animal model and to compare the initial ultimate loads of 3 graft fixation methods, including the use of EndoButton (EB), interference screw (IFS), and a novel socket anchoring (SA) technique.

METHODS

Porcine calcaneus bones and 5-mm-wide split bovine Achilles tendons were used as fixation bases and graft materials, respectively. Both ends were firmly sutured side-by-side, using the circumferential ligation technique as a double-strand substitute that was 45 mm in length. Porcine calcanei with similar characteristics to adult human calcanei were mounted on a tensile testing machine, and substitutes were fixed into bones using the 3 fixation methods. A polyester tape was passed through the tendon loop and connected to a crosshead jig of the testing machine. The initial ultimate loads were measured in 15 specimens for each fixation method to simulate a lateral ankle ligament (LAL) injury.

RESULTS

The ultimate loads (ULs) were 223.6 ± 52.7 N for EB, 229.7 ± 39.7 N for SA, and 208.8 ± 65.3 N for IFS. No statistically significant difference was observed among the 3 groups (P = .571). All failures occurred at the bone-ligament substitute interface.

CONCLUSION

The initial ULs in all 3 fixation methods were sufficient for clinical usage. These values were larger than the UL of the anterior talofibular ligament; however, these were smaller than the UL of the calcaneofibular ligament.

CLINICAL RELEVANCE

In an experimental animal model, ULs for SA, EB, and IFS techniques showed no significant difference. All failures were observed in the fixation site of the calcaneus and were overwhelmingly related to suture fixation failure.

Knots Tied With High-Tensile Strength Tape Biomechanically Outperform Knots Tied With Round Suture

Background

Tape-type suture material is well-accepted in arthroscopy surgery.

Purpose

To compare the knot security of a high-tensile strength round suture and high-tensile strength tape with commonly used arthroscopic knots.

Study Design

Controlled laboratory study.

Methods

We compared the performance of No. 2 braided nonabsorbable high-strength suture with that of 1.3-mm braided nonabsorbable high-strength tape. Five commonly used arthroscopic knots were investigated: the Roeder knot; the Western knot; the Samsung Medical Center (SMC) knot; the Tennessee knot; and a static surgeon's knot. Seven knots were tied for each combination of knots and suture types. Knots were tied on a 30-mm circumferential metal post, and the suture loops were transferred to a materials testing machine. After preloading to 5 N, all specimens were loaded to failure. The clinical failure load, defined as the maximal force to failure at 3 mm of crosshead displacement, yield load, and stiffness, were recorded. A 2-way analysis of variance was used to determine differences between the groups.

Results

Both suture type and knot type significantly affected the clinical failure load, yield load, and stiffness (P = .002). The high-strength tape resulted in a significantly greater clinical failure load than the high-strength suture in the case of the Roeder knot, Western knot, and SMC knot (P = .027, .005, and .016, respectively). When the high-strength round suture was used, the Roeder knot, Western knot, and SMC knot resulted in significantly smaller clinical failure loads compared with the Tennessee knot (P = .011, .003, and .035, respectively) and the static surgeon's knot (P < .001 for all). When the high-strength tape was used, the Roeder knot, Western knot, and SMC knot resulted in significantly smaller clinical failure loads compared with the static surgeon's knot (P = .001, .001, and .003, respectively).

Conclusion

The results of this study indicated that arthroscopic knots tied using 1.3-mm high-strength tape biomechanically outperformed knots tied using a No. 2 high-strength suture. While the static surgeon's knot exhibited the best biomechanical properties, the Tennessee knot resulted in generally better biomechanical properties among the arthroscopic sliding knots.

Clinical Relevance

Elongation and loosening of tied knots possibly affects the clinical results of repaired constructs.

All-Inside Arthroscopic Anterior Cruciate Ligament Reconstruction and Internal Brace With Recycling Suture

Anterior cruciate ligament (ACL) rupture is a common injury of the knee. Arthroscopic ACL reconstruction is a standard treatment for this condition. All-inside ACL reconstruction has many advantages compared with conventional techniques. However, there are still concerns regarding graft elongation and stability with all-inside ACL reconstruction. Here, we propose an arthroscopic technique using the shortening strands of a flexible suspensory button as an internal brace. This method provides the advantages of increased stability and ACL graft protection while using the same implant as the all-inside ACL reconstruction technique.