Treatment of Acute Proximal Anterior Cruciate Ligament Tears-Part 2: The Role of Internal Bracing on Gap Formation and Stabilization of Repair Techniques

Arthroscopic Primary Repair of Proximally Based Anterior Cruciate Ligament Tear With Augmentation and All-Epiphyseal Fixation

Arthroscopic anterior cruciate ligament (ACL) reconstruction has been the gold standard of care for ACL injuries for many years. Recently, there has been growing literature and interest in arthroscopic primary ACL repair in select patients with predominantly proximally based ACL tears. This Technical Note demonstrates a surgical technique that offers an efficient minimally invasive and physeal-sparing anatomic ACL repair with all-inside internal brace augmentation that in the short term has offered good results for our patients.

Primary anterior cruciate ligament repair-morphological and quantitative assessment by 7-T MRI and clinical outcome after 1.5 years

OBJECTIVES

The purpose of this study was to assess morphological and quantitative changes of the anterior cruciate ligament (ACL) and cartilage after ACL repair.

METHODS

7T MRI of the knee was acquired in 31 patients 1.5 years after ACL repair and in 13 controls. Proton density-weighted images with fat saturation (PD-fs) were acquired to assess ACL width, signal intensity, elongation, and fraying. T2/T2* mapping was performed for assessment of ACL and cartilage. Segmentation of the ACL, femoral, and tibial cartilage was carried out at 12 ROIs. The outcome evaluation consisted of the Lysholm Knee Score and International Knee Documentation Committee (IKDC) subjective score and clinical examination.

RESULTS

ACL showed a normal signal intensity in 96.8% and an increased width in 76.5% after repair. Fraying occurred in 22.6% without having an impact on the clinical outcome (Lysholm score: 90.39 ± 9.75, p = 0.76 compared to controls). T2 analysis of the ACL revealed no difference between patients and controls (p = 0.74). Compared to controls, assessment of the femoral and tibial cartilage showed a significant increase of T2* times in all ROIs, except at the posterolateral femur. Patients presented a good outcome in clinical examination with a Lysholm score of 87.19 ± 14.89 and IKDC of 80.23 ± 16.84.

CONCLUSION

T2 mapping results suggest that the tissue composition of the ACL after repair is similar to that of a native ACL after surgery, whereas the ACL exhibits an increased width. Fraying of the ACL can occur without having any impact on functional outcomes. T2* analysis revealed early degradation at the cartilage.

CLINICAL RELEVANCE STATEMENT

MRI represents a noninvasive diagnostic tool for the morphological and compositional assessment of the anterior cruciate ligament after repair, whereas knowledge about post-surgical alterations is crucial for adequate imaging interpretation.

KEY POINTS

• There has been renewed interest in repairing the anterior cruciate ligament with a proximally torn ligament. • T2 times of the anterior cruciate ligament do not differ between anterior cruciate ligament repair patients and controls. • T2 mapping may serve as a surrogate for the evaluation of the anterior cruciate ligament after repair.

Rehabilitation Following ACL Repair with Internal Brace Ligament Augmentation in Female Gymnast: A Resident's Case Report

Introduction

Anterior Cruciate Ligament (ACL) injuries continue to be a major source of morbidity in gymnastics. The gold standard is to perform an ACL Reconstruction (ACLR). However, injuries to the proximal femoral attachment of the ACL have demonstrated an ability to regenerate. An alternative surgical intervention to the ACLR in this ACL tear subgroup is an ACL repair. The purpose of this case report is to provide a rehabilitation progression for a female gymnast after an ACL repair with Internal Brace Ligament Augmentation (IBLA).

Case Description

The subject was a 16-year-old female who presented with a Sherman Type 1 proximal avulsion of her ACL. She underwent an ACL repair with IBLA. Physical therapy interventions followed a sequential and multi-phased approach based on time for tissue physiologic healing and individual progression. Patient reported outcomes including the International Knee Documentation Committee (IKDC), the Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) and the Optimal Screening for Prediction of Referral and Outcome Yellow Flag (OSPRO-YF) were assessed in conjunction with isokinetic strength and hop performance testing to determine return to sport readiness.

Outcomes

The subject completed 42 sessions over the course of 26 weeks in addition to a home exercise program. At return to sport, clinically meaningful improvement was observed in patient reported outcomes including the IKDC, ACL-RSI, and OSPRO-YF. Additionally, strength and hop performance surpassed established thresholds of clinical significance. The subject returned to sport at six months post-operatively.

Conclusion

The subject in this case report returned to full participation in gymnastics six months after an ACL repair with internal bracing following a sequential and multi-phased rehabilitation. The primary ACL repair with IBLA appeared beneficial to this patient and could benefit from additional study in other athletes and athletic populations.

Level of Evidence

Level 5.

Refixation of the anterior cruciate ligament: A biomechanical analysis of suture techniques in a porcine model

Purpose

Refixation of acute anterior cruciate ligament (ACL) tears represents an increasingly popular treatment option. Systematic evaluations of various suture technique parameters are still pending. We therefore aimed to evaluate the mechanical pull-out outcomes of various suture methods for optimization of ACL refixation.

Methods

Sixty fresh knees from mature domestic pigs were dissected and the femoral attachment of the ACL was peeled off. The 60 knees were divided in 10 groups and sutured as follows: (A) one suture (1, 2, 4 and 6 passes), (B) two sutures (2, 4 and 6 passes each; sutures knotted together as a loop) and (C) two sutures (2, 4 and 6 passes each, sutures knotted separately). The pull-out test was conducted using a validated electrodynamic testing machine. First occurrence of failure, maximum pull-out load and stiffness were measured. Suture failure was defined as pull-out of the ACL.

Results

Two-point fixation, using two sutures, with at least two passes, showed the most favourable biomechanical stability. The maximum pull-out load was significantly higher with two sutures (529.5 N) used compared to one (310.4 N), p < 0.001. No significant differences were found for maximum pull-out loads between two-point fixation versus one-point fixation but stiffness was significantly higher with two-point fixation (107.4 N/mm vs. 79.4 N/mm, p < 0.001). More passes resulted in higher maximum pull-out loads.

Conclusion

The results suggest using two independent sutures, refixed separately and at least two suture passes, is appropriate for ACL refixation. More suture passes provide additional strength but are technically challenging to achieve during surgery.

Level of Evidence

Level IV.

Stabilization and Gap Formation of Adjustable Versus Fixed Primary ACL Repair With Internal Brace: An in Vitro Full-Construct Biomechanical Cadaveric Study

Background

A knotless, tensionable primary anterior cruciate ligament (ACL) repair system preloaded with an internal brace has been released. Currently, there is no biomechanical data on the stabilization and gap formation behavior of the adjustable system when compared with fixed repairs in human ACL tissue.

Hypothesis

That knotless adjustable suture repair with an internal brace would provide overall higher construct stability and greater load share on the ACL with less gap formation compared with fixed repair.

Study Design

Controlled laboratory study.

Methods

Human cadaveric knees were utilized for internal braced ACL repair constructs (each group n = 16). Two fixed groups consisting of a single-cinch loop (SCL), cortical button (SCL group), and knotless suture-anchor (anchor group) were compared with an SCL-adjustable loop device (SCL-ALD) group. Testing was performed at 4 different peak loads (50, 150, 250, 350 N) over 4000 cycles at 0.75 Hz including suture repair preconditioning (10 cycles at 0.5 Hz) for SCL-ALD. Specimens were ultimately pulled to failure with a cut internal brace. The final loading situation of the construct and ACL repair with gap formation and ultimate strength were evaluated.

Results

Peak elongation at various peak loads showed a significantly higher (P < .001) stabilization of SCL-ALD when compared with both fixed groups. There was a significantly higher (P < .001) load share of SCL-ALD, especially at lower loads (48% of 50 N), and the gap formation remained restricted up to 250 N. With only a little load share on the fixed constructs (<6%) at lower loads (50, 150 N), gap formation in these groups started at a load of 150 N, leading to significantly higher gaps (P < .001). The ultimate failure load for SCL-ALD and anchor groups was significantly increased (P < .001) as compared with SCL. The stiffness of SCL-ALD (62.9 ± 10.6 N/mm) was significantly increased (P < .001).

Conclusion

Internal braced knotless adjustable fixation for ACL repair with preconditioning of the suture repaired ligament increased the overall stabilization with higher load share on the ACL and restricted gap formation (<0.5 mm up to 350 N) compared with fixed suture repair. All internal braced repairs restored stability according to native ACL function.

Clinical Relevance

Adjustable ACL repair improved the mechanical characteristics and reduced gap formation, but the overall clinical significance on healing remains unclear.

Categorize the existing clamps used for tensile test of human graft- a systematic review

BACKGROUND

The use of tendon allografts for orthopedic repair has gained wide acceptance in recent years, most notably in anterior cruciate tendon reconstruction. Multiple studies support the use of tendon allografts and the benefits of its use are well accepted and understood. One of the important criteria of the use of tendon allografts is statistically similar histological and biomechanical properties to autographs. The aim of this systematic literature review is to investigate and categorize existing clamps used in the determination of the biomechanical properties of tendons such as maximum load, maximum strength, modulus of elasticity, ultimate strain, and stiffness. A variety of clamps for use during the endurance test of tendons were categorized according to the temperature used during the measurement. The clamps are divided into three groups: room temperature, cooled and heated clamps. The second goal of our review is to overview of clamps on the following aspects: name of clamp, author and date, type of clamps, type of endurance test (static or dynamic), type preloading (dynamic or static), type of tendon and measured and calculated parameters, and summarize in Table 3, as a comprehensive catalogue.

METHODS

This systematic review was carried out in keeping with the PRISMA 2020 E&E and the PRISMA-S guidelines and checklists. A search was conducted for publications dating between 1991 and February 28th 2022 through three electronic databases (Web of Science, Scopus, and PubMed). We used Critical Appraisal Skills Program checklist to check the quality of included articles.

RESULTS

The database search and additional sources resulted in 1725 records. 1635 records eliminated during the screening for various reasons (case report, other languages, book chapter, unavailable text/conference abstract, unrelated topic). The number of articles used in the final synthesis was 90. A variety of clamps for use during the endurance test of tendons were identified and categorized according to the temperature used during the measurement. Based on this, the clamps are divided into three groups: room temperature, cooled or heated clamps.

CONCLUSIONS

On the basis of the systematic literature review, mechanical parameters determined by usage with cooled clamps proved to be more reliable than with those at room temperature and with heated clamps. The collected information from the articles included name of clamp, author and date, type of clamps, type of endurance test (static or dynamic), type preloading (dynamic or static), type of tendon and measured and calculated parameters given in Table 3. summarized. The main advantage of the cooled clamps is that there is no limit to the type and length of the tendon. This study provides an overview of clamps and does not represent the modernity of any method.

Anterior cruciate ligament repair with internal brace augmentation: A systematic review

BACKGROUND

Primary repair of anterior cruciate ligament (ACL) ruptures has re-emerged as a treatment option for proximal tears, with internal brace augmentation often utilised. The aim of this study is to provide an overview of the current evidence presenting outcomes of ACL repair with internal bracing to assess the safety and efficacy of this technique.

METHODS

All studies reporting outcomes of arthroscopic primary repair of proximal ACL tears, augmented with internal bracing from 2014-2021 were included. Primary outcome was failure rate and secondary outcomes were subjective patient reported outcome measures (PROMs) and objective assessment of anteroposterior knee laxity.

RESULTS

Nine studies were included, consisting of 347 patients, mean age 32.5 years, mean minimum follow up 2 years. There were 36 failures (10.4%, CI 7.4% - 14.1%). PROMs reporting was variable across studies. KOOS, Lysholm and IKDC scores were most frequently used with mean scores > 87%. The mean Tegner and Marx scores at follow-up were 6.1 and 7.8 respectively. The mean side to side difference measured for anteroposterior knee laxity was 1.2mm.

CONCLUSIONS

This systematic review with meta-analysis shows that ACL repair with internal bracing is a safe technique for treatment of proximal ruptures, with a failure rate of 10.4%. Subjective scores and clinical laxity testing also revealed satisfactory results. This suggests that ACL repair with internal bracing should be considered as an alternative to ACL reconstruction for acute proximal tears, with the potential benefits of retained native tissue and proprioception, as well as negating the need for graft harvest.

The Comparison of Clinical Result between Primary Repair of the Anterior Cruciate Ligament with Additional Internal Bracing and Anatomic Single Bundle Reconstruction-A Retrospective Study

BACKGROUND

The current standard of treatment of anterior cruciate ligament (ACL) is reconstruction (ACLR). This technique has some disadvantages: poor proprioception, donor site morbidity and the inability to restore joint kinematics. ACL repair could be an alternative treatment. The purpose of the study was to compare the stability and the function after ACL primary repair versus single-bundle ACLR.

METHODS

In a retrospective study, 12 patients underwent primary ACL repair with internal bracing, 15 patients underwent standard ACLR. Follow-up examinations were evaluated at up to 2 years postoperatively. One patient in the ACL repair group was lost to follow-up due to re-rupture. The absolute value of anterior tibial translation (ATT) and the side-to-side difference in the same patient (ΔATT) were evaluated using the GNRB arthrometer. The Lysholm knee scoring was obtained. Re-ruptures and other complications were recorded.

RESULTS

Anterior tibial translation (ATT) was significantly decreased in the ACL repair group compared with the ACLR group (5.31 mm vs. 7.18 mm, respectively; p = 0.0137). Arthrometric measurements demonstrated a mean side-to-side difference (ΔATT) 1.87 (range 0.2 to 4.9) mm significantly decreased compared to ACLR 3.36 (range 1.2-5.6 mm; p = 0.0107). The mean Lysholm score was 85.3 points in the ACL repair group and 89.9 in ACLR group. No significant differences between ACL repair and ACLR were found for the Lysholm score. There was no association between AP laxity and clinical outcomes. There were two complications in the internal bracing group: one patient had re-rupture and was treated by ACLR, another had limited extension and had arthroscopic debridement.

CONCLUSIONS

Anterior tibial translation was significantly decreased after ACL repair. Additionally, the functional results after ACL repair with internal bracing were comparable with those after ACLR. It should be noted that the two complications occurred. The current study supports further development of ACL repair techniques.

Combined Anterior Cruciate Ligament Repair and Anterolateral Ligament Reconstruction With a Single-Strand Gracilis Graft

There has been renewed interest in anterior cruciate ligament (ACL) repair procedures in the past decade. Even though ACL reconstruction is still considered the gold standard, ACL repair is an alternative in selected patients. However, the risk of failure owing to isolated ACL repair remains a concern. Intra-articular augmentation has been proposed to protect the repair during the healing period. In the same way, the protective effect of anterolateral ligament reconstruction on the ACL graft is increasingly recognized. We describe a combined ACL repair and anterolateral ligament reconstruction technique with a single-strand gracilis for the intra-articular portion and as an anterolateral graft to protect the ACL repair during the healing phase.

Arthroscopic ACL Reconstruction After Failed ACL Repair

For some authors, repair of the torn anterior cruciate ligament (ACL) in selected patients can be considered a valuable surgical treatment option. One of the main advantages is that it leaves all grafts available for any type of reconstruction in case the repair fails. This Technical Note describes arthroscopic ACL reconstruction after failure of an ACL repair.

Suture Tape Augmentation Has No Effect on Anterior Tibial Translation, Gap Formation, or Load to Failure of Anterior Cruciate Ligament Repair: A Biomechanical Pilot Study

Purpose

The purpose of our pilot study was to assess the effect of augmenting anterior cruciate ligament (ACL) repair with suture tape on biomechanical parameters including anterior tibial translation, gap formation, and load to failure.

Methods

Ten fresh-frozen nonpaired cadaveric knees were dissected, and baseline anterior-posterior stability of both ACL-intact and -deficient knees was obtained. The specimens were randomized to undergo ACL repair either with or without suture tape reinforcement, and anterior tibial translation, as well as gap formation, was measured after cyclic loading. Finally, all specimens were subjected to a single pullout force to determine maximum load to failure. We performed t test analysis to compare means between groups, and significance was defined as P < .05.

Results

On t test analysis, no statistically significant difference was found regarding anterior tibial translation between the ACL-intact group and either repair group or between the repair group without suture tape augmentation and the repair group with suture tape augmentation. No significant difference in gap formation was detected between the repair groups with and without suture tape augmentation at 100 cycles (1.25 mm vs 1.02 mm, P = .6), 250 cycles (2.87 mm vs 2.12 mm, P = .3), and 500 cycles (4.5 mm vs 4.55 mm, P = .5). The average load to failure of the repairs without suture tape augmentation was not significantly different from that of the repairs with suture tape augmentation (725.9 N vs 725.7 N, P = .99).

Conclusions

In this pilot study, we did not identify a difference between ACL repairs with and without suture tape augmentation regarding anterior tibial translation, gap formation, or maximum load to failure.

Clinical Relevance

Treatment of ACL tears with primary ACL repair is a highly debated topic, and studies such as this study to further our understanding of the biomechanical properties of augmented ACL repairs are important for surgeons when deciding the best treatments for their patients.

Knotless Primary Anterior Cruciate Ligament Repair with Adjustable Loop Device and Internal Brace Augmentation

With the recent resurgence of primary anterior cruciate ligament repair, it is important to strive for optimal patient outcomes. This knotless primary repair procedure takes advantage of the use of an adjustable loop device, which allows for intraoperative retensioning by the surgeon. This technical advancement combined with augmentation with an internal brace could potentially minimize gap formation at the repair site, thereby increasing repair stability and ultimate outcome.

Good to Excellent Functional Short-Term Outcome and Low Revision Rates Following Primary Anterior Cruciate Ligament Repair Using Suture Augmentation

The aim of this study was to evaluate the functional outcome of primary anterior cruciate ligament (ACL) repair using suture augmentation (SA) in 93 consecutive patients (67 female) with a minimum follow-up of 12 months. Patients’ outcomes were determined using International Knee Documentation Committee (IKDC) score, Lysholm score (LS) and Tegner score (TS). Knee-laxity was assessed using the KT-1000 arthrometer. Eighty-eight patients (67 female, mean age 42 years ± standard deviation (SD) 13) were available for follow-up after a mean time of 21 months (range 12–39). Three patients (3%) underwent revision surgery and were excluded from functional analysis. The mean IKDC score was 87.4 ± 11, mean LS was 92.6 ± 11, mean pre-traumatic TS was 6 ± 2 and mean postoperative TS was 6 ± 2, with a mean difference (TS_Diff) of 1 ± 1. The interval from injury to surgery had no significant impact on the postoperative IKDC (p = 0.228), LS (p = 0.377) and TS_Diff (p = 0.572). Patients’ age (>40 years), BMI (>30) and coexisting ligament or meniscal injuries did not seem to influence postoperative functional results. Primary ACL repair using SA provides good to excellent functional outcomes with a low probability of revision surgery at a minimum of 12 months.

The healing potential of an acutely repaired ACL: a sequential MRI study

Background

Recently, there has been renewed interest in primary anterior cruciate ligament (ACL) repair. The aim of this study is to report early clinical and radiological results of a consecutive series of acute ACL tears treated with arthroscopic primary ACL repair within 14 days from injury.

Patients and methods

A consecutive series of patients with acute ACL tears were prospectively included in the study. Based on MRI appearance, ACL tears were classified into five types, and tissue quality was graded as good, fair, and poor. Patients with type I, II, and III tears and at least 50% of ACL tibial remnant intact with good tissue quality were ultimately included. Clinical outcomes were measured using the Tegner Lysholm Knee Scoring Scale (TLKSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), subjective and objective International Knee Documentation Committee (IKDC) scores, and KT-1000. Patients were also followed up with MRI evaluations at 1, 3, and 6 months postoperatively. ACL appearance was graded based on morphology (normal or abnormal) and signal intensity (isointense, intermediate, and hyperintense).

Results

The mean TLKSS was 98.1, the mean subjective IKDC was 97.6, and the mean KOOS was 98.2. The objective IKDC score was A in eight of ten patients and B in two patients. KT-1000 measurements showed a maximum manual side-to-side difference of less than 2 mm in eight of ten patients, whereas two patients showed a difference of 3 mm. The morphology of the repaired ACL was normal (grade 1) at 1 month follow-up in ten of ten cases, and this appearance persisted at 3 and 6 months postoperatively. The signal intensity at 1 month postoperatively was graded as isointense (grade 1) in four of ten patients, intermediate (grade 2) in five of ten patients, and hyperintense (grade 3) in one of ten patients. At both 3 and 6 months postoperatively, the signal intensity was graded as isointense (grade 1) in nine of ten patients and intermediate (grade 2) in one of ten patients.

Conclusions

Arthroscopic primary ACL repair performed acutely in a carefully selected group of patients with proximal ACL tears and good tissue quality showed good early clinical and radiological results.

Level of evidence

Level 4.

Treatment of Acute Proximal Anterior Cruciate Ligament Tears-Part 2: The Role of Internal Bracing on Gap Formation and Stabilization of Repair Techniques

BACKGROUND

The latest biomechanical studies on some form of internal bracing have shown improved stabilization for anterior cruciate ligament (ACL) repair, but gap formation and load-sharing function have not yet been reported.

HYPOTHESIS

Internal bracing of an adjustable ACL repair construct provides improved stabilization with reduced gap formation and higher residual loading on the ACL.

STUDY DESIGN

Controlled laboratory study.

METHODS

Internally braced ACL repair constructs with single- and double-cinch loop (CL) cortical buttons, a knotless suture anchor, and a single-CL cortical button with adjustable loop fixation (CLS-ALD) were tested (n = 20 each) in a porcine model at 4 different loads (n = 5 each) over 4000 cycles at 0.75 Hz (n = 80 total). The CLS-ALD technique allowed for additional preconditioning (10 cycles at 0.5 Hz). Test results of the isolated internal brace groups served as a baseline for comparison. Lastly, specimens were pulled to failure (50 mm/min) with a cut internal brace. Final loading and gap formation on the ACL repair construct as well as ultimate strength were analyzed.

RESULTS

A statistical significance for peak loads over peak elongation was found between the CLS-ALD and all other reinforced groups (analysis of covariance, P < .001). Accordingly, the adjustable repair technique showed improved load-bearing capability with the internal brace compared with all other fixed repair groups and revealed significantly higher loads than the knotted single-CL group. Also, significantly reduced gap formation was found for the CLS-ALD compared with all other groups (P < .001), with no gap formation up to 150 N with a final gap of 0.85 ± 0.31 mm at 350 N. A significantly higher ultimate failure load (866.2 ± 104.0 N; P < .001) was found for the button-fixed internal brace group compared with all other groups.

CONCLUSION

Internal bracing had a crucial role in improving the stabilization potential of ACL repair at loads occurring during normal daily activity. The added strength of the internal brace allowed for reducing peak loads on the ACL repair construct as well as restricting gap formation to below 3 mm at loads up to 350 N.

CLINICAL RELEVANCE

Improvements in the mechanical characteristics of current ACL repair techniques that enable reduced gap formation and allow for early range of motion and accelerated rehabilitation may strengthen the self-healing response with the formation of stable scar tissue.