The use of the ligament augmentation and reconstruction system (LARS) for posterior cruciate reconstruction

Unicompartmental knee arthroplasty combined with posterior cruciate ligament reconstruction: a case report

BACKGROUND

In this study, we present the unique case of a patient with knee osteoarthritis (OA) of the medial compartment and posterior cruciate ligament (PCL) deficiency who underwent simultaneous medial unicompartmental knee arthroplasty (UKA) and PCL reconstruction.

CASE PRESENTATION

A 49-year-old male patient presented with a 1-year history of pain and instability in the left knee. The patient had previously experienced a trauma-related injury to the PCL of the left knee that was left untreated. Imaging and physical examination confirmed the presence of left medial knee OA along with PCL rupture. To address these issues, the patient underwent UKA combined with PCL reconstruction. The patient's Lysholm score was 47 before surgery and 81 three months after surgery, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was 29 before surgery and 18 three months after surgery, and the International Knee Documentation Committee (IKDC) subjective score was 56.3 before surgery and 74.7 three months after surgery. Six months after surgery, the patient's gait returned to normal, and he was able to jog.

CONCLUSION

This case report presents the first instance of UKA combined with PCL reconstruction and introduces a novel treatment approach for patients suffering from medial knee OA and ligament injury.

Silk fibroin-based scaffolds for tissue engineering

Silk fibroin is an important natural fibrous protein with excellent prospects for tissue engineering applications. With profound studies in recent years, its potential in tissue repair has been developed. A growing body of literature has investigated various fabricating methods of silk fibroin and their application in tissue repair. The purpose of this paper is to trace the latest developments of SF-based scaffolds for tissue engineering. In this review, we first presented the primary and secondary structures of silk fibroin. The processing methods of SF scaffolds were then summarized. Lastly, we examined the contribution of new studies applying SF as scaffolds in tissue regeneration applications. Overall, this review showed the latest progress in the fabrication and utilization of silk fibroin-based scaffolds.

Rotator Cuff Repair and Overlay Augmentation by Direct Interlocking of a Nonwoven Polyethylene Terephthalate Patch Into the Tendon: Evaluation in an Ovine Model

BACKGROUND

Arthroscopic repair of large rotator cuff tendon tears is associated with high rates of retear. Construct failure often occurs at the suture-tendon interface. Patch augmentation can improve mechanical strength and healing at this interface.

PURPOSE

To introduce a novel technique for suture-free attachment of an overlaid patch and evaluate its biomechanical strength and biological performance.

STUDY DESIGN

Descriptive and controlled laboratory studies.

METHODS

An established ovine model of partial infraspinatus tendon resection and immediate repair was used. After a nonwoven polyethylene terephthalate patch was overlaid to the resected tendon, a barbed microblade was used to draw fibers of the patch directly into the underlying tissue. In vivo histological assessment of healing was performed at 6 and 13 weeks after implantation. Ex vivo models were used to characterize primary repair strength of the suture-free patch fixation to tendon. Additional ex vivo testing assessed the potential of the technique for patch overlay augmentation of suture-based repair.

RESULTS

The in vivo study revealed no macroscopic evidence of adverse tissue reactions to the interlocked patch fibers. Histological testing indicated a normal host healing response with minimal fibrosis. Uniform and aligned tissue ingrowth to the core of the patch was observed from both the tendon and the bone interfaces to the patch. There was no evident retraction of the infraspinatus muscle, lengthening of the tendon, or tendon gap formation over 13 weeks. Ex vivo testing revealed that direct patch interlocking yielded tendon purchase equivalent to a Mason-Allen suture (150 ± 58 vs 154 ± 49 N, respectively; P = .25). In an overlay configuration, fiber interlocked patch augmentation increased Mason-Allen suture retention strength by 88% (from 221 ± 43 N to 417 ± 86 N; P < .01) with no detectable difference in repair stiffness.

CONCLUSION

Testing in an ovine model of rotator cuff tendon repair suggested that surgical interlocking of a nonwoven medical textile can provide effective biomechanical performance, support functional tissue ingrowth, and help avoid musculotendinous retraction after surgical tendon repair.

CLINICAL RELEVANCE

The novel technique may facilitate patch augmentation of rotator cuff repairs.

Comparison of Posterior Cruciate Ligament Reconstruction Using an All-Inside Technique With and Without Independent Suture Tape Reinforcement

Background

Biomechanical studies support the use of suture tape reinforcement for limiting graft elongation and increasing strength in knee ligament reconstructions.

Purpose

To compare posterior cruciate ligament (PCL) laxity, complication and reoperation rates, and patient-reported outcomes (PROs) after all-inside single-bundle PCL reconstruction (PCLR) with versus without independent suture tape reinforcement.

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective cohort study of consecutive patients who underwent primary, all-inside allograft single-bundle PCLR with and without independent suture tape reinforcement at a single academic institution from 2012 to 2019. Medical records were reviewed for patient characteristics, additional injuries, and concomitant procedures. PRO scores (including the International Knee Documentation Committee [IKDC], Tegner activity scale, and Lysholm scores), bilateral comparison kneeling radiographs, and physical examination findings were collected at a minimum of 2 years postoperatively.

Results

Included were 50 patients: 19 with suture tape reinforcement (mean age 30.6 ± 2.9 years) and 31 without suture tape reinforcement (control group; mean age 26.2 ± 1.6 years). One PCLR graft in the suture tape group failed. Posterior drawer examination revealed grade 1+ laxity in 4 of 19 (21%) of the suture tape cohort versus 6 of 31 (19%) of the control cohort (P > .999). Bilateral kneeling radiographs showed similar side-to-side differences in laxity between the groups (suture tape vs control: mean, 1.9 ± 0.4 vs 2.6 ± 0.6 mm; P = .361). There were no statistically significant differences between the groups in postoperative IKDC (suture tape vs control: 79.3 vs 79.6; P = .779), Lysholm (87.5 vs 84.3; P = .828), or Tegner activity (5.6 vs 5.7; P = .562) scores.

Conclusion

All-inside single-bundle PCLR with and without independent suture tape reinforcement demonstrated low rates of graft failure, complications, and reoperations, with satisfactory PROs at a minimum 2-year follow-up. Radiographic posterior tibial translation was comparable between the 2 groups.

Hybrid Nanofibrous Composites with Anisotropic Mechanics and Architecture for Tendon/Ligament Repair and Regeneration

Rupture of tendons and ligaments (T/L) is a major clinical challenge due to T/L possess anisotropic mechanical properties and hierarchical structures. Here, to imitate these characteristics, an approach is presented by fabricating hybrid nanofibrous composites. First, hybrid fiber-reinforced yarns are fabricated via successively electrospinning poly(L-lactide-co-ε-caprolactone) (PLCL) and gelatin (Ge) nanofibers onto polyethylene terephthalate (PET) fibers to improve biodurability and biocompatibility. Then, by comparing different manufacturing methods, the knitted structure succeeds in simulating anisotropic mechanical properties, even being stronger than natural ligaments, and possessing comfort compliance superior to clinically used ligament advanced reinforcement system (LARS) ligament. Moreover, after inoculation with tendon-derived stem cells and transplantation in vivo, hybrid nanofibrous composites are integrated with native tendons to guide surrounding tissue ingrowth due to the highly interconnected and porous structure. The knitted hybrid nanofibrous composites are also ligamentized and remodeled in vivo to promote tendon regeneration. Specifically, after the use of optimized anisotropic hybrid nanofibrous composites to repair tendon, the deposition of tendon-associated extracellular matrix proteins is more significant. Thus, this study indicates a strategy of manufacturing anisotropic hybrid nanofibrous composites with superior mechanical properties and good histocompatibility for clinical reconstruction.

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.

The use of the ligament augmentation and reconstruction system for posterior cruciate ligament reconstruction in isolated and multiligament knee injuries: A systematic review

PURPOSE

To evaluate the efficacy and safety of the Ligament Augmentation and Reconstruction System (LARS) in posterior cruciate ligament (PCL) reconstruction in isolated PCL injuries and multiligament knee injuries, analysing clinical, radiographic, and patient reported outcome measures (PROMs).

METHODS

A systematic review according to PRISMA guidelines was performed through Embase via Ovid, PubMed, and the Cochrane Library to identify studies reviewing LARS use for PCL reconstruction. The methodological quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria.

RESULTS

From 225 results screened, 13 studies were included published between 2004 and 2020, analysing LARS use for PCL reconstruction. Mean follow-up was 21 months to 11.9 years, however only four studies had follow-up of over five years. Results in isolated PCL reconstruction utilising LARS demonstrated scores that were consistent with good function and minimal limitation in daily or sporting activities, in addition to a significant improvement in knee laxity and low complication rates. Symptomatic rupture and synovitis rates were both 1.7% in this group. LARS use in complex multiligament injuries demonstrated satisfactory PROMs, although there was concern regarding residual laxity on stress radiography.

CONCLUSIONS

LARS demonstrates good outcomes in PCL injury reconstruction in the short to mid-term, particularly in isolated PCL injuries, achieving equivocal or improved results compared to autograft reconstruction using hamstring tendon in the three comparative studies included. LARS has a quicker recovery time and no donor-site morbidity, however long-term data is lacking. Utilising LARS for reconstruction of the PCL in multiligament injuries revealed more variable results.

Injury to the Medial Superior Genicular Artery After Isolated Posterior Cruciate Ligament Reconstruction: A Case Report

CASE

A 19-year-old male patient with isolated posterior cruciate ligament (PCL) rupture underwent arthroscopic reconstruction using reinforced synthetic ligament (LARS system). Three weeks postoperatively, he presented with active bleeding from the medial side of his knee, near the proximal interference screw. An angiogram revealed extravasation from the medial superior genicular artery which was successfully embolized. One week later, he returned with active bleeding from the same area, located just under the initial coiling; a second embolization during superselective angiography was successful.

CONCLUSION

Although rare, minor vascular injuries are a risk inherent to PCL surgery.

Anatomic Double Bundle Posterior Cruciate Ligament Reconstruction Using an Internal Splint

Techniques for reconstruction of posterior cruciate ligament (PCL) tears are rapidly evolving. One problem with current techniques is that laxity may develop early in the postoperative period, leading to relapsed posterior translation of the tibia. Therefore, maintaining tibial reduction during graft incorporation is a target for improvement. We describe using an internal splint to optimize the 4-tunnel, double-bundle allograft PCL reconstruction.

Autografts vs Synthetics for Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

To describe the outcomes of autografts and synthetics in anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction with respect to instrumented laxity measurements, patient‐reported outcome scores, complications, and graft failure risk. We searched PubMed, Cochrane Library, and EMBASE for published randomized controlled trials (RCT) and case controlled trials (CCTs) to compare the outcomes of the autografts versus synthetics after cruciate ligament reconstruction. Data analyses were performed using Cochrane Collaboration RevMan 5.0. Nine studies were identified from the literature review. Of these studies, three studies compared the results of bone–patellar tendon–bone (BPTB) and ligament augmentation and reconstruction system (LARS), while six studies compared the results of four‐strand hamstring tendon graft (4SHG) and LARS. The comparative study showed no difference in Lysholm score and failure risk between autografts and synthetics. The combined results of the meta‐analysis indicated that there was a significantly lower rate of side‐to‐side difference > 3 mm (Odds Ratio [OR] 2.46, 95% confidence intervals [CI] 1.44–4.22, P = 0.001), overall IKDC (OR 0.40, 95% CI 0.19–0.83, P = 0.01), complications (OR 2.54, 95% CI 1.26–5.14, P = 0.009), and Tegner score (OR −0.31, 95% CI −0.52–0.10, P = 0.004) in the synthetics group than in the autografts group. This systematic review comparing long‐term outcomes after cruciate ligament reconstruction with either autograft or synthetics suggests no significant differences in failure risk. Autografts were inferior to synthetics with respect to restoring knee joint stability and patient‐reported outcome scores, and were also associated with more postoperative complications.

Posterior cruciate ligament reconstruction implemented by the Ligament Advanced Reinforcement System over a minimum follow-up of 10 years

PURPOSE

This study evaluated the long-term clinical follow-up results of patients who underwent double-bundle posterior cruciate ligament (PCL) reconstruction using the Ligament Advanced Reinforcement System (LARS).

METHODS

Patients were assessed using clinical scores that included the Tegner activity level scale, the Lysholm score, and the International Knee Documentation Committee (IKDC) score. KT-1000 was adopted to assess stability. Radiographs and magnetic resonance imaging (MRI) were used to evaluate osteoarthritis and LARS condition.

RESULTS

This study examined 38 patients, of which follow-up procedures were completed for 33 patients, resulting in a follow-up rate of 86.8%. The average follow-up period was 11.9 ± 1.2 years (range: 10.3-14.2 years). The median scores of the clinical scales were as follows: Tegner activity score, 6 (range: five to seven); Lysholm score, 90 (range: 67-100); and IKDC score, 89.7 (range: 46-100). The median of the side-to-side difference (SSD) was four millimeters (range: 0-10 mm). In radiographs, the moderate OA rate was 6.9%. MRI results revealed that 26 patients exhibited ingrowth and 11 patients exhibited partial rupture of the LARS. With SSD ≤ 3 mm set as the standard for successful knee stabilization, the optimal cutoff point of LARS midsubstance thickness in the receiver operating characteristic (ROC) curve analysis was 14.3 mm.

CONCLUSIONS

Long-term follow-up of the studied patients demonstrated the durability of LARS. However, clinical outcomes showed no enhancement using LARS, so it is not recommended for routine use in PCL reconstruction.

LEVEL OF EVIDENCE

IV.

Posterior Cruciate Ligament Repair With Suture Tape Augmentation

The posterior cruciate ligament (PCL) acts as the primary restraint to posterior tibial translation of the knee. Injuries to the PCL are rare in isolation and more often are associated with multiligament injuries to the knee. Several PCL reconstruction and PCL repair techniques have been described in the literature, but no single technique has been shown to be the most superior. Internal bracing with suture tape augmentation encourages natural healing and allows early mobilization. This article describes, with video illustration, PCL repair with suture tape augmentation.

LARS synthetic ligaments for the acute management of 111 acute knee dislocations: effective surgical treatment for most ligaments

PURPOSE

The purpose of this study was to describe the longitudinal outcomes of acute repair and augmentation for the reconstruction of dislocated knees, using LARS synthetic ligaments.

METHODS

Patients with a knee dislocation surgically treated using LARS synthetic ligament augmentation, with a minimum follow-up of 24 months, were enrolled between 1996 and 2014. Range of motion, Lachman, pivot shift, posterior drawer, step off sign, valgus, varus, KT-1000 arthrometer, Telos technique, IKDC, Lysholm, Tegner, and Meyers scores were obtained every 2 years up to 10 years.

RESULTS

Median age was 32.1 years (IQR 23.2-43.3) at time of surgery. Median time from trauma to surgery was 9 days and mean follow-up time was 6.6 years. Median questionnaire scores were: Lysholm 79.5 (IQR 65.0-89.0), Tegner 4.0 (IQR 3.7-6.0), Meyers 3.0 (IQR 3.0-4.0), and mean IKDC was 63.8 (SD 18.9). Median flexion and extension of the injured knee was 124° (IQR 115-129.5) and 0° (IQR - 5 to 0), respectively. Median KT-1000 differential was 0.7 mm (IQR 0.1-3.1) for ACL and 0.9 mm (IQR 0.2-1.4) for PCL. Mean differential for Telos was 2.5 mm (SD 5.8) for ACL, 4 mm (IQR 2-6.3) for PCL 30°, and 8.2 mm (SD 4.4) for PCL 90° (consistent with PCL laxity). More than 90% of patients had good anterior articular stability and > 60% of patients had good posterior articular stability.

CONCLUSIONS

Acute repair and augmentation of knee dislocations with LARS synthetic ligaments resulted in satisfactory outcomes for the ACL and collateral structures. Telos stress radiography showed PCL laxity in more than half of cases despite low laxity results with KT-1000. The perception of patients about knee function was sustained in time.

LEVEL OF EVIDENCE

IV.

Complex knee injuries treated in acute phase: Long-term results using Ligament Augmentation and Reconstruction System artificial ligament

AIM

To present the long-term results of complex knee injuries, treated early using the Ligament Augmentation and Reconstruction System (LARS) artificial ligament to reconstruct posterior cruciate ligament (PCL).

METHODS

From September 1997 to June 2010, thirty-eight complex knee injuries were treated, where early arthroscopic PCL reconstructions were undergone, using the LARS (Surgical Implants and Devices, Arc-sur-Tille, France) artificial ligament. Exclusion criteria were: Late (> 4 wk) reconstruction, open technique, isolated PCL reconstruction, knee degenerative disease, combined fracture or vascular injury and use of allograft or autograft for PCL reconstruction. Clinical and functional outcomes were assessed with IKDC Subjective Knee Form, KOS-ADLS questionnaire, Lysholm scale and SF-12 Health Survey. Posterior displacement (PD) was measured with the Telos Stress Device.

RESULTS

Seven patients were excluded; two because of co-existing knee osteoarthritis and the remaining five because of failure to attend the final follow-up. The sample consisted of 31 patients with mean age at the time of reconstruction 33.2 ± 12.5 years (range 17-61). The postoperative follow-up was on average 9.27 ± 4.27 years (range 5-18). The mean average IKDC and KOS scores were 79.32 ± 17.1 and 88.1 ± 12.47% respectively. Average PD was 3.61 ± 2.15 mm compared to 0.91 ± 1.17 mm in the uninjured knees (one with grade 1 + and two with grade 2 +). Dial test was found positive in one patient, whereas the quadriceps active drawer test was positive in three patients. None was tested positive on the reverse-pivot shift test. The range of motion (ROM) was normal in thirty knees, in comparison with the contralateral one. There was no extension deficit. Osteoarthritic changes were found in three knees (9.6%).

CONCLUSION

Early treatment of complex knee injuries, using LARS artificial ligament for PCL reconstruction sufficiently reduces posterior tibia displacement and provides satisfactory long-term functional outcomes.

Orthopedic Interface Repair Strategies Based on Native Structural and Mechanical Features of the Multiscale Enthesis

The enthesis is an organ that connects a soft, aligned tissue (tendon/ligament) to a hard, amorphous tissue (bone) via a fibrocartilage interface. Mechanically, the enthesis sustains a dynamic loading environment that includes tensile, compressive, and shear forces. The structural components of the enthesis act to minimize stress concentrations and control stretch at the interface. Current surgical repair of the enthesis, such as in rotator cuff repair and anterior cruciate ligament reconstruction, aim to bridge the gap between the injured ends via reattachment of soft-to-hard tissues or graft replacement. In this review, we discuss the multiscale, morphological, and mechanical characteristics of the fibrocartilage attachment. Additionally, we review historical and recent clinical approaches to treating enthesis injury. Lastly, we explore new technological advancements in tissue-engineered biomaterials that have shown promise in preclinical studies.

Effects of graphene modification on the bioactivation of polyethylene-terephthalate-based artificial ligaments

The objective of this study was to investigate whether surface coating with graphene could enhance the surface bioactivation of PET-based artificial ligaments to accelerate graft-to-bone healing after anterior cruciate ligament reconstruction. In an in vitro study, the proliferation of MC3T3-E1 cells and their differentiation on the scaffolds were quantified via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and real-time polymerase chain reaction assays. The significantly higher optical-density values and transcription levels of osteoblast-specific genes indicated that graphene modification could promote the proliferation of MC3T3-E1 cells and accelerate their specific differentiation into osteogenic lineages on scaffolds. In an in vivo test, rabbits were used to establish an extra-articular graft-to-bone healing model. At 4, 8, and 12 weeks after surgery, biomechanical tests, microcomputed tomography analysis, and histological observations were performed. The final results demonstrated that the microstructural parameters, the average mineral apposition rate of the bone, and the biomechanical properties of the graphene-coated polyethylene terephthalate (PET)-based artificial ligament (G-PET-AL) group were significantly higher than those of the PET-AL graft group (P < 0.05). The results of Van Gieson staining indicated that in the G-PET-AL group, there was more newly formed bone than there was in the group in which nongraphene-coated PET-ALs were used. In conclusion, graphene exhibits considerable potential for enhancing the surface bioactivation of materials.

Editorial commentary: synthetic ACL grafts are more important than clinical nonbelievers may realize

Artificial ACL grafts are structural ties, designed to resist tension, but not designed to undergo biologic ligamentization by the host. Strategically, an artificial ACL graft may be used as reinforcement to augment ACL repair, ACL autograft, ACL allograft, or tissue-engineered ACL. Most artificial ACL grafts have had poor reported outcomes. However, the Ligament Augmentation and Reconstruction System (LARS) artificial ACL graft shows positive clinical outcomes.

Status and headway of the clinical application of artificial ligaments

The authors first reviewed the history of clinical application of artificial ligaments. Then, the status of clinical application of artificial ligaments was detailed. Some artificial ligaments possessed comparable efficacy to, and fewer postoperative complications than, allografts and autografts in ligament reconstruction, especially for the anterior cruciate ligament. At the end, the authors focused on the development of two types of artificial ligaments: polyethylene glycol terephthalate artificial ligaments and tissue-engineered ligaments. In conclusion, owing to the advancements in surgical techniques, materials processing, and weaving methods, clinical application of some artificial ligaments so far has demonstrated good outcomes and will become a trend in the future.