Anterior cruciate ligament reconstruction with LARS™ artificial ligament results at a mean follow-up of eight years

Functional and MRI results after a 7.5 year follow-up of 35 single-stage ACL and PCL reconstructions using gracilis and semitendinosus tendon grafts and LARS artificial ligaments

PURPOSE

The aim of this study was to evaluate the long-term functional and MRI results of 35 patients who underwent bicruciate ligament reconstruction combining an ACL autograft using the gracilis and semitendinosus tendons and double-bundle PCL reconstruction using the LARS artificial ligament.

METHODS

The outcomes were measured using the Lysholm score, the Tegner activity level scale and the International Knee Documentation Committee form (IKDC 2000). KT-1000 was used to assess the clinical anterior knee laxity. Radiographs and Magnetic Resonance Imaging (MRI) was used to evaluate osteoarthritis, the continuity and integrity of ACL autograft and LARS.

RESULTS

This retrospective study examined 35 patients who underwent single-stage bicruciate ligament reconstruction between May 2005 and January 2017 with a follow-up period ranging from 3 to 15 years (a mean of 7.5 years). The mean Lysholm score was 74, mean IKDC 2000 was 71. There was a statistically significant difference with a higher Lysholm score (78.9) in early versus delayed surgical intervention (p = 0.023). Using the Kellgren Lawrence osteoarthritis classification system, radiographic findings showed stage II or III in 83% of the sample population. The MRI results revealed a rupture rate of 22% of the anterior autografted ligament and 28% of the posterior LARS artificial ligament. However, there were no long-term artificial ligament-induced complications. There was no correlation between artificial ligament rupture and poor functional results (Lysholm < 65).

CONCLUSION

The results of this study with a mean follow-up of 7.5 years show satisfactory functional scores considering the initial trauma. It seems reasonable to propose early surgical treatment with double reconstruction of the cruciate ligaments within the first 21 days of the trauma. Post-traumatic osteoarthritis is inevitable in multi-ligament knee injuries despite anatomical reconstruction. The use of a LARS artificial ligament appears to be a valid alternative for PCL reconstruction in the context of multi-ligament injury and in the absence of sufficient autologous transplants.

Silver nanoparticles-decorated extracellular matrix graft: fabrication and tendon reconstruction performance

BACKGROUND

The reconstruction of tendons with large defects requires grafts with high mechanical strength and is often hindered by complications such as infection and adhesion. Hence, grafts combining the advantages of mechanical resilience and antibacterial/antiadhesion activity are highly sought after.

METHODS

The silver nanoparticles (GA-Ag NPs) synthesized from gallic acid and silver nitrate were attached to a decellularized extracellular matrix (Decellularized Tendon crosslinking GA-AgNPs, DT-Ag). We examined the histological structure, mechanical property, morphology, Zeta potential, cytotoxicity, antibacterial properties, antioxidant and anti-inflammatory properties, and ability of the DT-Ag to treat tendon defects in animals.

RESULTS

Approximately 108.57 ± 0.94 μg GA-Ag NPs loaded per 50 mg DT, the cross-linked part of GA-Ag NPs was 65.47 ± 0.57%, which provided DT-Ag with long-lasting antibacterial activity. Meanwhile, GA endowed DT-Ag with good antioxidant and anti-inflammatory activities. Additionally, The DT-Ag facilitated M2 macrophage polarization, and suppressed fibrin deposition by hindering fibroblast adhesion. Mormore, the main advantages of DT-Ag, namely its long-lasting antibacterial activity (tested using Escherichia coli and Staphylococcus aureus as models) and the ability to prevent tissue adhesion were confirmed in vivo.

CONCLUSION

The fabricated multifunctional tendon graft was highly hydrophilic, biocompatible, and mechanically resilient, and concluded to be well suited for dealing with the main complications of surgical tendon reconstruction and has bright application prospects.

Anterior Cruciate Ligament Reconstruction Using Autologous Hamstrings Augmented with Ligament Augmentation and Reconstruction Systems (LARS) or Synthetic Meshwork of LARS Compared with Four-Strand Hamstring Tendon Grafts Alone, a Prospective, Randomized Clinical Study with 2- to 8-Year Follow-Up

Purpose

To compare the long-term outcomes of anterior cruciate ligament (ACL) reconstruction using a four-strand hamstring tendon graft alone (hamstring group) or with synthetics (Ligament Augmentation and Reconstruction System, LARS group) or synthetic meshwork of LARS (meshwork group).

Methods

Patients who underwent ACL reconstruction using four-strand hamstring tendon grafts (hamstring group), autologous hamstrings augmented with the LARS (LARS group), or synthetic meshwork of LARS (meshwork group) were selected in this prospective randomized clinical study. Patient-reported outcome measures (PROMs) were obtained preoperatively; at 6, 12, and 18 months postoperatively; and at final follow-up between 3 and 8 years. Second-look arthroscopic findings were used to evaluate graft morphology based on graft tension, graft tear, and synovial coverage.

Results

A total of 141 consecutive patients underwent ACL reconstruction, 47 patients in each group, and 21 patients were lost to follow-up during the study period. At the 6-month follow-up, the IKDC scores and Lysholm scores were significantly better in the LARS group (P < 0.05). At the 6- and 12-month follow-ups, the KOS-ADLS, KOOS-activities of daily living and quality of life, NSARS scores, GRC scores, Tegner scores, and ACL-RSI scores were significantly better in the LARS group (P < 0.05). For the LARS group, hamstring group, and meshwork group, the cumulative failure rates were 8.5%, 12.8%, and 4.3%, respectively. Malposition of the femoral tunnel was significantly associated with cumulative failure (P < 0.05). There was no difference between the groups in other outcomes at any other time, including radiographic and arthroscopic outcomes.

Conclusions

ACL reconstruction using autologous hamstring augmented with LARS resulted in significantly better clinical scores with a faster return to sports and comparative side-to-side differences in graft laxity by 6 and 12 months follow-up. Despite these findings, no statistically significant differences were seen among the three patient groups in terms of objective outcomes and clinical scores at the 18-month, 3-year and 8-year follow-ups. Additionally, a malpositioned femoral tunnel was associated with graft failure.

Ligament augmentation repair is broadly applied across different orthopaedic subspecialities: an ISAKOS international survey of orthopaedic surgeons

OBJECTIVES

To evaluate how ligament augmentation repair (LAR) techniques are currently used in different anatomic regions in orthopaedic sports medicine, and to identify the most common indications and limitations of LAR.

METHODS

We sent survey invitations to 4,000 members of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine society. The survey consisted of 37 questions total, with members only receiving some branching questions specific to their area of specialisation. Data were analysed using descriptive statistics, and the significance between groups was evaluated using chi-square tests of independence.

RESULTS

Of 515 surveys received, 502 were complete and included for the analysis (97% completion rate). 27% of respondents report from Europe, 26% South America, 23% Asia, 15% North America, 5.2% Oceania, and 3.4% Africa. 75% of all survey respondents report using LAR, most frequently using it for the anterior talofibular ligament ( 69%), acromioclavicular joint ( 58%), and the anterior cruciate ligament (51%). Surgeons in Asia report using LAR the most (80%), and surgeons in Africa the least (59%). LAR is most commonly indicated for additional stability (72%), poor tissue quality (54%), and more rapid return-to-play (47%). LAR users state their greatest limitation is cost (62%), while non-LAR users state their greatest reason not to use LAR is that patients do well without it (46%). We also find that the frequency of LAR use among surgeons may differ based on practice characteristics and training. For example, surgeons who treat athletes at the professional or Olympic level are significantly more likely to have a high annual use of LAR (20+ cases) compared to surgeons that treat only recreational athletes (45% and 25%, respectively, p ​= ​0.005).

CONCLUSION

LAR is broadly applied in orthopaedics but its rate of use is not homogeneous. Outcomes and perceived benefits vary depending on factors such as surgeon specialty and treatment population.

LEVEL OF EVIDENCE

Level V.

Reconstruction of chronic anterior cruciate ligament rupture using the ligament advanced reinforcement system artificial ligament-comparisons between patients over 50 years and under 50 years

Background

With the increasing physical activity level in elderly population, anterior cruciate ligament (ACL) injuries are becoming more frequent. Due to the possible surgery complications, treatment for ACL rupture in patients with advanced age is still controversial. The purpose of this study was to compare the therapeutic effects of reconstruction using the ligament advanced reinforcement system (LARS) artificial ligament in patients older than 50 and patients younger than 50 with chronic ACL rupture.

Methods

Indications included: (I) concurrent history of subjective symptomatic anterior knee instability despite nonoperative rehabilitation for least 3 months, (II) positive preoperative Lachman and pivot shift tests, (III) ACL stump still connecting the femur with the tibia as demonstrated by Magnetic Resonance Imaging (MRI), and (IV) some residual ligament fibers still connecting the femur with the tibia as demonstrated by arthroscopy. Participants were divided into groups based on their age. Participants were divided into groups based on their age. A total of 37 patients who underwent reconstruction of chronic ACL rupture using the LARS artificial ligament were divided into group A (≥50 years, n=16) and group B (<50 years, n=21).

Results

The outcome measures were compared between the 2 groups. These included the baseline clinical data, the International Knee Documentation Committee (IKDC) scoring system, Pivot shift test, Lachman test, Kneelax arthrometer measurements, Tegner activity scale, Lysholm knee scoring scale, and Kellgren-Lawrence radiographic classification of arthritis and complications. Postoperative knee laxity and the functional examination were significantly improved compared to preoperative measurements for both groups (all P<0.01). No significant differences were found in postoperative knee laxity and functional examination between the 2 groups (all P>0.05). The level of osteoarthritis did not statistically increase in either group during follow-up (all P>0.05). No complications associated with the arthroscopic surgery were found in either group.

Conclusions

The reconstruction of chronic ACL rupture using the LARS artificial ligament showed similar therapeutic effects in patients over the age of 50 and those under the age of 50.

Mussel-Based Biomimetic Strategies in Musculoskeletal Disorder Treatment: From Synthesis Principles to Diverse Applications

Musculoskeletal disorders are the second leading cause of disability worldwide, posing a huge global burden to the public sanitation system. Currently, tissue engineering-based approaches act as effective strategies, which are, however, challenging in limited application scenarios. Mussel-based biomimetic materials, exhibit numerous unique properties such as intense adhesion, biocompatibility, moisture resistance, and injectability, to name only a few, and have attracted extensive research interest. In particular, featuring state-of-the-art properties, mussel-inspired biomaterials have been widely explored in innumerable musculoskeletal disorder treatments including osteochondral defects, osteosarcoma, osteoarthritis, ligament rupture, and osteoporosis. Nevertheless, a comprehensive and timely discussion of their applications in musculoskeletal disorders is insufficient. In this review, we emphasize on (1) the main categories and characteristics of mussel foot proteins and their fundamental mechanisms for the spectacular adhesion in mussels; (2) the diverse synthetic methods and modification of various polymers; and (3) the emerging applications of mussel-biomimetic materials, the future perspectives, and challenges, especially in the area of musculoskeletal disorder. We envision that this review will provide a unique and insightful perspective to improve the development of a new generation of mussel biomimetic strategies.

Allogeneic Tendon Transplantation for the Treatment of Pathological Patellar Ligament Defect in Children: Technical Note and 4-Year Follow-Up

OBJECTIVE

The absence of patellar ligament will bring about a severe negative impact on daily life. Many reconstruction techniques have been described in adults. However, there is a lack of technical introduction regarding the reconstruction of the patellar ligament in children. The purpose of this study was to report a surgical technique for reconstructing the patellar ligament in children.

METHOD

A retrospective analysis of the clinical data on a patellar ligament (tendon sheath fibroma) patient with allogeneic tendon reconstruction. An 8-year-old child with postoperative recurrence of left patellar ligament tumor was enrolled in our study. Anterior tibialis tendon allograft was used to reconstruct the patellar ligament after complete resection of the patellar ligament for the tumor. The tunnels were constructed on the deep surface of the tibial tubercle and the root of the quadriceps tendon (to decrease the harmful impact on patella development), respectively. The allogeneic tendon was passed through the tunnels above in the shape of "8," and the two ends of the tendon were attached to the bleeding bone bed at the inferior edge of the patella with suture anchors to achieve better bone-tendon healing. During the follow-up, the knee's range of motion and imaging manifestations were recorded.

RESULT

Postoperative pathology suggests chondromesenchymal hamartoma, a rare benign soft tissue tumor different from the previous operation (tendon sheath fibroma). During the 4-year follow-up, the patient's active range of motion of the knee achieved 0° to 120°; and the patient could walk normally without any external help. Physical examinations (the apprehension sign and J sign) showed no ligamentous instability or patellar ligament tenderness. Imaging analysis showed that the ratio length of the patellar ligament to the patella was almost normal. The integrity, continuity, and shape of the allogeneic ligament showed excellent results in MRI. Combined with clinical and imaging findings, allogeneic tendon patellar ligament reconstruction was deemed successful.

CONCLUSION

Allogeneic ligament reconstruction technique can provide a treatment option by reconstructing the extensor mechanism, minimizing the impact on patellar development, and augmenting biological healing for children with the absence of the patellar ligament.

Current strategies for enhancement of the bioactivity of artificial ligaments: A mini-review

Background and objective

Anterior cruciate ligament (ACL) reconstruction calls for artificial ligaments with better bioactivity, however systematic reviews regarding bioactivity enhancement strategies, technologies, and perspectives of artificial ligaments have been rarely found.

Methods

Research papers, reviews, and clinical reports related to artificial ligaments were searched and summarized the current status and research trends of artificial ligaments through a systematic analysis.

Results

Having experienced ups and downs since the very first record of clinical application, artificial ligaments differing in material, and fabrication methods have been reported with different clinical performances. Various manufacturing technologies have developed and realized scaffold- and cell-based strategies. Despite encouraging in-vivo and in-vitro test results, the clinical results of such new designs need further clinical examinations.

Conclusion

As the demand for ACL reconstruction dramatically increases, novel artificial ligaments with better osteoinductivity and mechanical performance are promising.

The translational potential of this article

To develop novel artificial ligaments simultaneously possessing excellent osteoinductivity and satisfactory mechanical performance, it is important to grab a glance at recent research advances. This systematic analysis provides researchers and clinicians with comprehensive and comparable information on artificial ligaments, thus being of clinical translational significance.

The efficacy and medium-term outcomes of ligament advanced reinforcement system compared with auto-grafts in anterior cruciate ligament reconstruction: At least 2 years follow-up

Background: Graft choice is an important step in the pre-operative plan of anterior cruciate ligament reconstruction (ACLR). The four-strand hamstring tendon (4SHT) is the most widely used auto-graft, while the Ligament Advanced Reinforcement System (LARS) is the newest typical biomaterial for ACLR. The physical activity level (PAL) before injury can affect the efficacy and outcomes of ACLR. This study aims to compare the efficacy and functional outcomes between ACLR using LARS and 4SHT in patients different PALs.

Methods: This was a prospective paired case-control study. ACL rupture patients included from 1 January 2017 to 31 December 2019 were subsequently divided into the high and plain PAL groups, according to their baseline PAL before injury. Clinical assessments included: Lachman test, pivot shift test, ligament laxity, Lysholm and International Knee Documentation Committee (IKDC) scores, and rate of returning to sports. The minimum follow-up was 2 years (y).

Results: A total of 58 patients had accomplished the 2 y follow-up (missing rate: 6.5%). In the high PAL group (n = 22), the positive rate of A–P laxity of the LARS subgroup was lower than the 4SHG subgroup (p = 0.138), while the Lysholm score (p = 0.002), IKDC score (p = 0.043), and rate of returning to sports (p = 0.010) of the LARS were higher than the 4SHG at 1 year follow-up; the positive rates of A–P laxity (p = 0.009) and pivot test (p = 0.027) were lower in the LARS than the 4SHG at 2 y follow-up. In the plain PAL group (n = 36), the positive rate of A–P laxity in the LARS subgroup was lower than the 4SHG at 1 year follow-up (p = 0.017); the positive rates of A–P laxity (p = 0.001), Lachman (p = 0.034), and pivot tests (p = 0.034) in the LARS were also lower than the 4SHG at 2 y follow-up, but the IKDC score (p = 0.038) and rate of returning to sports (p = 0.019) in the 4SHG were higher than the LARS.

Conclusion: In patients with high PAL, LARS can acquire better knee stability, sooner functional recovery, and returning to sports than 4SHG, while in patients without high PAL, 4SHG acquires better functional outcomes and a higher rate of returning to sports.

Differences in artificial ligament graft osseointegration of the anterior cruciate ligament in a sheep model: a comparison between interference screw and cortical suspensory fixation

Background

Interference screws are the most common femoral fixation for anterior cruciate ligament (ACL) reconstruction with polyethylene terephthalate (PET) artificial ligaments. However, interference screws have several disadvantages, such as the risk of one tunnel blowout and damage to the graft. Suspensory fixations have the advantages of high tensile strength and promotion of graft bone contact. The purpose of this study was to compare PET artificial ligament graft osseointegration between interference screw fixation (ISF) and cortical suspensory fixation (CSF) for ACL reconstruction.

Methods

Forty sheep underwent ACL reconstruction of the right knee with PET artificial ligament. The graft was fixed with ISF or CSF for femoral fixation. Animals were randomly assigned to the ISF (n=20) or the CSF (n=20) groups. The sheep were sacrificed at 3 or 12 months postoperatively for biomechanical tests, micro computed tomography (micro-CT) scans, and histological assessments.

Results

The mean load-to-failure between the CSF group (836±355 N) appeared higher than that of the ISF group (604±277 N) at 3 months, but no significant difference was detected between the groups (P=0.24). At 12 months, there was also no significant difference in load-to-failure between the CSF and ISF groups (1,194±350 vs. 1,097±764 N; P=0.78). According to the micro-CT scan results, the femoral bone tunnel diameter of the ISF group appeared larger than that of the CSF group at 3 months (12±1 vs. 10±1 mm; P=0.02) and similar to that of the CSF group at 12 months (12±1 vs. 11±2 mm; P=0.38). Furthermore, histological results showed that at the graft-tunnel interface of the femoral tunnel aperture, disoriented fibers formed in the ISF group while oriented and dense fibers formed in the CSF group.

Conclusions

ACLR with synthetic ligament by cortical suspension devices with adjustable loops demonstrated a better graft-bone healing capacity at the femoral tunnel aperture compared with that from titanium interference screws over 12 months postoperatively. No significant difference was found in biomechanical strength between the two fixation methods during the early healing stage.

Cell-Free Book-Shaped Decellularized Tendon Matrix Graft Capable of Controlled Release of BMP-12 to Improve Tendon Healing in a Rat Model

BACKGROUND

Achilles tendon (AT) defects often occur in traumatic and chronic injuries. Currently, no graft can satisfactorily regenerate parallel tendinous tissue at the defect site to completely restore AT function.

PURPOSE

To develop a cell-free functional graft by tethering bone morphogenetic protein 12 (BMP-12) on a book-shaped decellularized tendon matrix (BDTM) and to determine whether this graft is more beneficial for AT defect healing than an autograft.

STUDY DESIGN

Controlled laboratory study.

METHODS

Canine patellar tendon was sectioned into a book shape and decellularized to fabricate a BDTM. The collagen-binding domain (CBD) was fused into the N-terminus of BMP-12 to synthesize a recombinant BMP-12 (CBD-BMP-12), which was tethered to the BDTM to prepare a cell-free functional graft (CBD-BMP-12/BDTM). After its tensile resistance, tenogenic inducibility, and BMP-12 release dynamics were evaluated, the efficacy of the graft for tendon regeneration was determined in a rat model. A total of 140 mature male Sprague-Dawley rats underwent AT tenotomy. The defect was reconstructed with reversed AT (autograft group), native BMP-12 tethered to an intact decellularized tendon matrix (IDTM; NAT-BMP-12/IDTM group), native BMP-12 tethered to a BDTM (NAT-BMP-12/BDTM group), CBD-BMP-12 tethered on an IDTM (CBD-BMP-12/IDTM group), and CBD-BMP-12 tethered on a BDTM (CBD-BMP-12/BDTM group). The rats were sacrificed 4 or 8 weeks after surgery to harvest AT specimens. Six specimens from each group at each time point were used for histological evaluation; the remaining 8 specimens were used for biomechanical testing.

RESULTS

In vitro CBD-BMP-12/BDTM was noncytotoxic, showed high biomimetics with native tendons, was suitable for cell adhesion and growth, and had superior tenogenic inducibility. In vivo the defective AT in the CBD-BMP-12/BDTM group regenerated more naturally than in the other groups, as indicated by more spindle-shaped fibroblasts embedded in a matrix of parallel fibers. The biomechanical properties of the regenerated AT in the CBD-BMP-12/BDTM group also increased more significantly than in the other groups.

CONCLUSION

CBD-BMP-12/BDTM is more beneficial than autograft for healing AT defects in a rat model.

CLINICAL RELEVANCE

The findings of this study demonstrate that CBD-BMP-12/BDTM can serve as a practical graft for reconstructing AT defects.

Medium-Term (Least 5 Years) Comparative Outcomes in Anterior Cruciate Ligament Reconstruction Using 4SHG, Allograft, and LARS Ligament

OBJECTIVE

To compare the clinical efficacy of anterior cruciate ligament (ACL) reconstruction with 4-strand hamstring tendon autograft (4SHG), allograft and the Ligament Advanced Reinforcement System (LARS) ligament, and to find the causes of cumulative failure or nonreturn to sport.

DESIGN

Retrospective case series.

SETTING

Department of Orthopedic Surgery, the second affiliated hospital of Soochow University, Suzhou, Jiangsu, China.

PATIENTS

Three hundred six patients with isolated ACL deficiency were included. Two hundred twenty-nine patients met the inclusion/exclusion criteria, and finally, 185 of these patients participated in this study.

INTERVENTIONS

Anterior cruciate ligament reconstruction using 4SHG, allograft, and LARS.

MAIN OUTCOME MEASURES

Objective knee function, subjective knee function, and information regarding return to sport, cumulative failure, and complications. Secondary: distribution of tunnel position and tunnel enlargement.

RESULTS

There were no statistically significant differences between the 3 groups regarding all the clinical objective and subjective results, return to sport, complications, or cumulative failures (P > 0.05). One hundred twenty-eight patients (69.2%, 128/185) returned to sport. Preoperative (after injury) Tegner scores were inferior to postoperative Tegner scores, and postoperative Tegner scores were inferior to preinjury Tegner scores (P < 0.01). The femoral tunnel malposition was significantly associated with cumulative failure (P < 0.05).

CONCLUSIONS

There were no statistically significant differences among the 4SHG, allograft, and LARS ligament in terms of the clinical outcomes after ACL reconstruction (ACLR) at 5-years follow-up. Interestingly, ACLR could improve the functional and motorial level of the knee, but patients had great difficulty in regaining the level of preinjury movement. In addition, the malposition of the femoral tunnel was an important cause of cumulative failure.

A Cell-free Biodegradable Synthetic Artificial Ligament for the Reconstruction of Anterior Cruciate Ligament in a Rat Model

Traditional Anterior Cruciate Ligament (ACL) reconstruction is commonly performed using an allograft or autograft and possesses limitations such as donor site morbidity, decreased range of motion, and potential infection. However, a biodegradable synthetic graft could greatly assist in the prevention of such restrictions after ACL reconstruction. In this study, artificial grafts were generated using "wet" and "dry" electrospinning processes with a biodegradable elastomer, poly (ester urethane) urea (PEUU), and were evaluated in vitro and in vivo in a rat model. Four groups were established: (1) Wet PEUU artificial ligament, (2) Dry PEUU artificial ligament, (3) Dry polycaprolactone artificial ligament (PCL), and (4) autologous flexor digitorum longus tendon graft. Eight weeks after surgery, the in vivo tensile strength of wet PEUU ligaments had significantly increased compared to the other synthetic ligaments. These results aligned with increased infiltration of host cells and decreased inflammation within the wet PEUU grafts. In contrast, very little cellular infiltration was observed in PCL and dry PEUU grafts. Micro-computed tomography analysis performed at 4 and 8 weeks postoperatively revealed significantly smaller bone tunnels in the tendon autograft and wet PEUU groups. The Wet PEUU grafts served as an adequate functioning material and allowed for the creation of tissues that closely resembled the ACL.

Quadriceps or patellar ligament reconstruction with artificial ligament after total knee replacement

BACKGROUND AND AIM OF THE WORK

Ruptures of the quadriceps or patellar tendon after TKA implantation are a fearful and disabling complication. Direct reconstructions highlighted various problems, such as the decrease in extensor force, failure, need for prolonged post-operative immobilization. So augmentation techniques have been proposed with autologous tendons, allografts, artificial ligaments. Among these, the LARS seems the most modern and promising. For this reason, we have retrospectively reviewed a case series patients operated with this artificial ligament, to evaluate the results and highlight the tips and tricks for this procedure.

METHODS

Ten patients with a mean age of 69.4 years suffered an extensor apparatus lesion after knee replacement. These patients underwent primary reconstruction and augmentation with LARS. They were retrospectively reviewed at a mean follow-up of 3.8 years, by measuring active flexion and extension, and by Lysholm scoring scale.

RESULTS

We did not observe any problems with healing of the surgical wound, nor phenomena of intolerance to the implanted material, such as inflammation, skin rashes or fistulas. The mean flexion was 117 degrees. Active extension was allowed in all patients, but with a mean extensor lag of 18 degrees. The mean Lysholm score was 74.2.

CONCLUSIONS

LARS offers good results without completely solving the problem of extensor lag, linked to the softness of the tissues in the quadriceps. The major advantages of LARS reside in the good tissue ingrowth, the absence of adverse tissue reactions, the ubiquitous availability, the possibility of stable fixation with early rehabilitation.

Which role for synthetic ligaments in the reconstruction of patellar tendon chronic rupture after TKA? Mid-term outcomes using LARS ligament

BACKGROUND AND AIM OF THE WORK

Patellar tendon rupture is a rare complication after Total Knee Arthroplasty (TKA) which often requires surgical treatment. Patients with chronic lesions or tendon degenerations showed good results when treated using autografts or allografts, but these techniques showed poor outcomes at long-term follow-up (FU). Moreover, allografts have high costs and limited availability, not to mention the increased risk of immune reactions and infections. Recently, the use of synthetic ligaments for patellar tendon reconstruction has taken hold with encouraging results. We report our experience in the treatment of patellar tendon ruptures after TKA using the Ligament Advanced Reinforcement System-LARS®.

METHODS

Clinical evaluation was performed using the Knee Society Score and recording extensor lag. Instrumental evaluation was performed using ultrasound imaging to assess patellar tendon thickness and using conventional x-rays to assess prosthesis' mobilization signs and patella's height.

RESULTS

At the final FU, 6 knees were included in our study. Patient's mean age was 66.7. Patellar tendon reconstruction occurred after a mean time of 4 months from the previous surgery. The mean FU was 44,2 months. The mean Knee Score was 63.3 and the mean Function Score was 35. In 4 knees the extensor lag was < 10° while in 2 knees it was > 20°. The mean ISI was 1.16, while the average increment in tendon thickness was 127.12%.

CONCLUSIONS

In our opinion, synthetic ligaments can be successfully employed for the reconstruction of patellar tendon breakage after TKA and rTKA in selected patients, in order to quickly return them to their activity of daily living.

Enhanced Biomechanical Performance of a Modern Polyester Surgical Mesh for Extensor Mechanism Reconstruction in Total Knee Arthroplasty

BACKGROUND

Extensor mechanism (EM) disruption following total knee arthroplasty is a devastating postoperative complication. Reconstruction with a synthetic mesh is one treatment option, although the optimal mesh material remains unknown. This study sought to compare the mechanical properties of 2 mesh material types that can be used for EM reconstruction.

METHODS

Mechanical properties of a polypropylene mesh (Marlex mesh) and Ligament Advanced Reinforcement System (LARS) mesh were compared using force-displacement data from a material testing machine simulating knee movement during normal human gait. Tension to failure/ultimate tensile load, stiffness coefficients, axial strain, and cyclic hysteresis testing were measured and calculated.

RESULTS

Compared to polypropylene mesh, LARS mesh demonstrated a significantly higher mean ultimate tensile load (2223 N vs 1245 N, P = .002) and stiffness coefficient (255 N/mm vs 14 N/mm, P = .035) in tension to failure testing, and significantly more energy dissipation (hysteresis) in hysteresis testing (771 kJ vs 23 kJ; P ≤ .040). LARS mesh also demonstrated significantly less maximum displacement compared to the polypropylene mesh (9.2 mm vs 90.4 mm; P ≤ .001).

CONCLUSION

Compared to polypropylene mesh, LARS mesh showed superior performance related to force-displacement testing. The enhanced mechanical performance of LARS mesh may correlate clinically to fewer failures, increased longevity, and higher resistance to plastic deformation (extensor lag). Future research should evaluate survivorship and clinical outcomes of these meshes when used for EM reconstruction.

Metal-based nanoparticles for bone tissue engineering

Tissue is vital to the organization of multicellular organisms, because it creates the different organs and provides the main scaffold for body shape. The quest for effective methods to allow tissue regeneration and create scaffolds for new tissue growth has intensified in recent years. Tissue engineering has recently used some promising alternatives to existing conventional scaffold materials, many of which have been derived from nanotechnology. One important example of these is metal nanoparticles. The purpose of this review is to cover novel tissue engineering methods, paying special attention to those based on the use of metal-based nanoparticles. The unique physiochemical properties of metal nanoparticles, such as antibacterial effects, shape memory phenomenon, low cytotoxicity, stimulation of the proliferation process, good mechanical and tensile strength, acceptable biocompatibility, significant osteogenic potential, and ability to regulate cell growth pathways, suggest that they can perform as novel types of scaffolds for bone tissue engineering. The basic principles of various nanoparticle-based composites and scaffolds are discussed in this review. The merits and demerits of these particles are critically discussed, and their importance in bone tissue engineering is highlighted.

Role of Biomaterials and Controlled Architecture on Tendon/Ligament Repair and Regeneration

Engineering synthetic scaffolds to repair and regenerate ruptured native tendon and ligament (T/L) tissues is a significant engineering challenge due to the need to satisfy both the unique biological and biomechanical properties of these tissues. Long-term clinical outcomes of synthetic scaffolds relying solely on high uniaxial tensile strength are poor with high rates of implant rupture and synovitis. Ideal biomaterials for T/L repair and regeneration need to possess the appropriate biological and biomechanical properties necessary for the successful repair and regeneration of ruptured tendon and ligament tissues.

[Artificial ligaments applied in anterior cruciate ligament repair and reconstruction: Current products and experience]

The application of artificial ligament products in anterior cruciate ligament (ACL) surgeries has gone through a long twisty way. In the 1970s, early artificial ligament products were initially used for ACL surgeries, which showed poor clinical efficacy and eventually ended up in failure. Over the last 20 years, there has been a growing number of ACL reconstruction with new artificial ligament products, including the Leeds-Keio TM, the LARS TM (Ligament Advanced Reinfocement System), and the Trevira Hochfest TM. Among these new products, the LARS TM has been more commonly applied for ACL surgeries. Although these new artificial ligament products have good mechanical properties and show significant improvement of cumulative failure and complication rate, they still have limitations.

Primary ACL reconstruction using the LARS device is associated with a high failure rate at minimum of 6-year follow-up

PURPOSE

The Ligament Augmentation and Reconstruction System (LARS^®) is a synthetic ligament consisting of fibres made of polyethylene terephthalate. Despite the LARS being used as an anterior cruciate ligament (ACL) device for nearly 30 years and the well-documented complications from earlier synthetic ligament designs, there is a paucity of published medium- to long-term results. The aim of this study is to report the clinical and functional outcomes after ACL reconstruction using the LARS at a minimum follow-up of 6 years.

METHODS

Results of a single surgeon's entire cohort of 55 patients who underwent primary LARS ACL surgery were reviewed at a median of 7.8 years (6.0-9.4). Patient-reported outcome measures including the International Knee Documentation Committee (IKDC) score and 36-Item Short Form Health Survey (SF-36) were collected and clinical assessment consisted of range of motion (ROM) and the KT-1000 arthrometer to assess the side-side difference in the operative and non-operative knee. Mechanical failures of the graft were confirmed at revision surgery and a survivorship analysis was performed using the Kaplan-Meier method.

RESULTS

The overall mechanical failure rate was 17/51 (33.3%) with ruptures occurring at a median 3.9 years (0.6-8.8 years) following primary LARS ACL surgery. Secondary operative procedures were performed in 39.2% of patients. For intact grafts, there was no statistically significant difference is side-to-side ROM or anterior knee laxity and subjective scores revealed a median IKDC subjective score of 85.1 (26.4-100) and SF-36 physical component score of 94.1.

CONCLUSION

The rates of LARS ACL construct failure (33.3%) in this cohort are high and based on these results the LARS should not be considered as a graft option for primary ACL reconstruction.

LEVEL OF EVIDENCE

III, cohort study.

Synovitis following anterior cruciate ligament reconstruction using the LARS device

PURPOSE

The Ligament Augmentation and Reconstruction System (LARS^®) has been at the forefront of a recent revival in the use of synthetic ligaments for ACL reconstruction. However, despite promising short-to-mid-term results its role has been approached with caution due to a high number of major complications in previous synthetic graft designs including mechanical failures, synovitis and osteoarthritis. This study aims to report on the incidence of synovitis in a series of patients undergoing second-look surgery following LARS ACL reconstruction.

METHODS

A retrospective analysis was performed of a single surgeon's series of 12 patients that underwent second-look arthroscopic surgery following primary LARS ACL surgery for indications including mechanical symptoms (meniscal tears/cyclops lesions/chondral flaps) and/or symptomatic instability secondary to LARS failure. In all cases an examination under anaesthesia (EUA) was performed, and a qualitative assessment of the synovium was carried out and graded as normal, reactive or inflammatory. A synovial biopsy was performed in all knees with visible evidence of synovitis and in all cases of LARS failure.

RESULTS

The second-look arthroscopy was performed at a mean of 23 months (7-66) after the index surgery. In 6 (50%) knees the LARS device had failed necessitating removal and revision ACL reconstruction, while in the remaining 6 knees the LARS was still intact. Arthroscopic evaluation of the synovium revealed a normal appearance in 8 knees (67%) and reactive synovitis in 4 knees (23%); of these 4 knees, one had an intact LARS device and 3 had failed LARS. Histological examination from these 4 knees and the 3 knees with graft failures without visible synovitis revealed chronic hypertrophic synovitis (moderate 2, mild 5) in all cases with rare giant cells, consistent with a reaction to foreign body material.

CONCLUSIONS

Foreign body synovitis is a common finding in our series of patients undergoing a repeat arthroscopy following a LARS ACL reconstruction. The histological diagnosis of synovitis was more frequently encountered than an arthroscopic appearance of synovitis. Whilst the results of this case series cannot support a direct causative link between LARS failure and the development of synovitis, this study highlights the need to remain vigilant about the risk of reactive synovitis following LARS ACL reconstruction due to exposure of the knee to foreign body material.

LEVEL OF EVIDENCE

Level IV, case series.

A randomized comparison between lateral ligaments augmentation using suture-tape and modified Broström repair in young female patients with chronic ankle instability

BACKGROUND

Although various minimally invasive procedures for chronic ankle instability are increasingly being used, a question regarding whether these procedures can be a viable alternative of the modified Broström procedure remains controversial. This study was conducted to compare the intermediate-term clinical outcomes between lateral ligaments augmentation using suture-tape and modified Broström repair in a selected cohort of patients.

METHODS

Sixty female patients with chronic lateral ankle instability were randomly assigned and underwent surgical treatments by one surgeon. Twenty-eight patients with suture-tape augmentation and 27 modified Broström procedures were followed ≥2 years and analysed in this comparative study. The clinical evaluation included the Foot and Ankle Outcome Score (FAOS), Foot and Ankle Ability Measure (FAAM), and stress radiographs. Medical expense related with operation was analysed to evaluate the cost-effectiveness.

RESULTS

There were no statistically significant differences in the clinical outcomes between two procedures based on FAOS, FAAM, recurrence rate of instability, and stress radiographs. Total medical expense was approximately 1.3 times more in the suture-tape group (P<0.001), despite shorter operation time.

CONCLUSIONS

Lateral ankle ligaments augmentation using suture-tape showed the similar clinical outcomes but low cost-effectiveness, as compared to modified Broström repair for young female patients with chronic ankle instability.

Activity-related outcome in anterior cruciate ligament reconstruction with synthetic ligament advanced reinforcement system

BACKGROUND

Arthroscopic anterior cruciate ligament (ACL) reconstruction with ligament advanced reinforcement system (LARS) had revealed good results with low complication and failure rate in series of studies. The specific candidates for ACL reconstruction with LARS are still unknown anyway. The purpose of this study is to evaluate the activity-related outcome in ACL reconstruction using LARS ligament.

METHODS

A total of 43 unilateral arthroscopic ACL reconstructions with LARS were collected and divided into two groups: group A (preinjury Tegner score ≥ 6, n = 20) and group B (preinjury Tegner score < 6, n = 23). We had analyzed the stability of knee and functional outcome with a minimum of 2-years follow up.

RESULTS

All patients were aware of improvement over the knee stability immediately after ACL reconstruction with LARS. The functional outcome of knee was improved in both groups by analysis with the Lysholm score and modified International Knee Documentation Committee (IKDC) score. The postoperative grading of the knee examination form of modified IKDC grade showed no statistical difference in both groups.

CONCLUSION

Arthroscopic ACL reconstruction with LARS was encouraged as an alternative option even in high sports demand patients.

Anterior Cruciate Ligament Reconstruction Using a Bone-Patellar Tendon-Bone Graft With and Without a Ligament Augmentation Device: A 25-Year Follow-up of a Prospective Randomized Controlled Trial

Background

Various grafts and ligament augmentation devices (LADs) have been used in the search for optimal reconstruction of the anterior cruciate ligament (ACL).

Purpose

To compare 25-year follow-up results after ACL reconstruction using a bone-patellar tendon-bone (BPTB) graft with or without the Kennedy LAD.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

One hundred patients undergoing ACL reconstruction between 1991 and 1993 were randomized into 2 groups: reconstruction using a BPTB graft alone (BPTB group, 51 patients) or a BPTB graft with the Kennedy LAD (LAD group, 49 patients). The 25-year follow-up evaluation included a clinical knee examination, patient-reported outcome measures, and an assessment of radiological osteoarthritis (OA) according to the Ahlbäck classification. Additional outcomes were reruptures and knee arthroplasty.

Results

Ninety-three patients (93%) were available for the follow-up evaluation: 48 patients in the BPTB group and 45 in the LAD group. Through telephone calls, 26 patients were excluded from further investigation because of reruptures and arthroplasty in the knee of interest; 67 patients were further investigated. A total of 43 of 44 (98%) and 42 of 44 (95%) patients had negative or 1+ Lachman and pivot-shift test results, respectively. The mean Lysholm score was 85 for the BPTB group and 83 for the LAD group. All mean Knee injury and Osteoarthritis Outcome Score (KOOS) subscale values were ≥73. There were no statistically significant differences between groups in any of these outcomes or regarding the Tegner score, radiological classification of OA, or number of ACL reruptures. Signs of radiological OA were detected in all patients, and severe radiological OA (Ahlbäck grade III, IV, or V) was detected in 32% of patients in the BPTB group and 21% of patients in the LAD group (P = .37). There were 12 patients in the BPTB group and 7 in the LAD group who had documented reruptures (P = .40). One patient in the BPTB group and 6 in the LAD group underwent knee arthroplasty (P = .054).

Conclusion

In the present study, there were no statistically significant differences between groups in any of the outcomes. After 25 years, 19% of patients had reruptures, 27% had severe radiological OA, and 7% underwent knee arthroplasty.

Anterior Cruciate Ligament Reconstruction with LARS Artificial Ligament-Clinical Results after a Long-Term Follow-Up

Purpose  The aim of this retrospective study was to evaluate the subjective and functional outcome of anterior cruciate ligament (ACL) reconstruction with the synthetic Ligament Advanced Reinforcement System (LARS) ligament.

Methods  Twenty-six patients were reviewed at an average follow-up of 11.6 years. Objective clinical evaluation was performed with stability tests. Patient-reported outcomes (Visual Analogue Scale, Knee Injury and Osteoarthritis Outcome Score, and Cincinnati Knee Rating Scale) were used to assess subjective and functional outcomes.

Results  Overall satisfactory results were obtained in 22 cases (84.6%). Four patients (15.4%) showed mechanical failure of the graft. No cases of synovitis or infection were reported.

Conclusion  LARS ligament can be considered a safe and suitable option for ACL reconstruction in carefully selected cases, especially elderly patients needing a rapid postoperative recovery.

Level of Evidence  Level IV, retrospective case series.

Long-Term Outcomes of Anterior Cruciate Ligament Reconstruction Using Either Synthetics With Remnant Preservation or Hamstring Autografts: A 10-Year Longitudinal Study

BACKGROUND

The optimal graft choice of anterior cruciate ligament (ACL) reconstruction remains controversial.

PURPOSE

To compare the outcomes, especially the long-term cumulative failure rate, of ACL reconstruction using either synthetics with remnant preservation or hamstring autografts (4-strand semitendinosus and gracilis tendons).

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 133 patients who underwent ACL reconstruction (synthetics: n = 43; hamstring autografts: n = 90) between July 2004 and December 2007 were included. Questionnaires (Tegner activity scale, Lysholm knee scale, and International Knee Documentation Committee [IKDC] subjective form) were completed preoperatively and at 6 months, 1 year, 5 years, and 10 years postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was additionally applied at 10 years' follow-up. The physical examination was based on the 2000 IKDC form. The manual maximum side-to-side difference (KT-1000 arthrometer), single-hop test, thigh muscle atrophy, and joint degeneration (Kellgren and Lawrence classification) were evaluated. The Kaplan-Meier curve and log-rank test (Mantel-Cox, 95% CI) were used to compare graft survivorship.

RESULTS

Ten years postoperatively, 111 patients were available, with 38 (88.4%) patients (mean age, 27.6 ± 9.3 years; 28 men) with synthetics and 73 (81.1%) patients (mean age, 28.6 ± 8.8 years; 64 men) with hamstring autografts. Among them, 104 patients (synthetics: n = 35 [81.4%]; hamstring autografts: n = 69 [76.7%]) completed subjective evaluations, and 89 patients (synthetics: n = 30 [69.8%]; hamstring autografts: n = 59 [65.6%]) completed objective evaluations. For hamstring autografts and synthetics, the cumulative failure rates were 8.2% and 7.9%, respectively, and the log-rank test demonstrated no significant difference between the 2 Kaplan-Meier survival curves ( P = .910). At 6 months postoperatively, for hamstring autografts and synthetics, the mean Lysholm score was 83.0 ± 7.8 and 88.1 ± 7.5, respectively ( P < .001); the mean IKDC score was 83.8 ± 7.8 and 86.9 ± 4.5, respectively ( P = .036); and the mean Tegner score was 3.7 ± 1.1 and 5.0 ± 1.5, respectively ( P < .001). At 1 year postoperatively, the mean Tegner score was 5.5 ± 1.9 and 6.5 ± 2.0, respectively ( P = .011). No statistically significant difference was observed on other subjective evaluation findings, physical examination findings (overall IKDC grade A: 45.8% of hamstring autografts, 50.0% of synthetics), side-to-side difference (1.5 ± 1.5 mm for synthetics, 2.4 ± 2.1 mm for hamstring autografts), single-hop test findings (grade A: 84.7% of hamstring autografts, 93.3% of synthetics), grade A/B thigh muscle atrophy (88.1% of hamstring autografts, 93.3% of synthetics), ipsilateral radiographic osteoarthritis (55.9% of hamstring autografts, 50.0% of synthetics), and graft survivorship.

CONCLUSION

In this prospective cohort study, primary ACL reconstruction using either synthetics with remnant preservation or hamstring autografts showed satisfactory outcomes, especially the long-term cumulative failure rate, at 10 years postoperatively. Patient-reported outcomes suggested that symptom relief and restoration of function might occur earlier in those with synthetics.

Comparison of artificial graft versus autograft in anterior cruciate ligament reconstruction: a meta-analysis

BACKGROUND

Critically evaluation and summarization for the outcomes between autografts and artificial grafts using in anterior cruciate ligament (ACL) reconstruction have not been performed currently. The purpose of this study is to compare the clinical outcomes between artificial ligaments and autografts at a short- to mid-term follow-up.

METHODS

A computerized search of the databases was conducted including Medline, Embase, and the Cochrane library. Only prospective or retrospective comparative studies with a minimum 2-year follow-up and a minimum sample size of 15 for each group were considered for inclusion. Two independent reviewers performed data extraction and methodological quality assessment. A Mantel-Haenszel analysis was used for pooling of results. Sensitivity analysis was performed in order to maintain the stability of results.

RESULTS

Seven studies were included in this study. The total sample size was 403 (autograft group: 206 patients; synthetic graft group: 197 patients). Four studies were randomized controlled trials. Two studies were retrospective comparative studies and one study was non-randomized prospective comparative study. In terms of instrumented laxity, patient-oriented outcomes and complications, no significant difference was occurred between new artificial ligaments and autografts. But the results of IKDC grades and instrumented laxity were worsen in early artificial ligaments compared to autografts.

CONCLUSIONS

The outcomes of new generation of artificial ligaments are similar to autografts at a short- to mid-term follow-up. However, the early artificial ligaments are not suggested for ACL reconstruction compared to autografts.

Use of Estradiol Promotes Graft-Bone Healing in Rabbit Model of Anterior Cruciate Ligament Reconstruction With a Polyethylene Terephthalate Ligament

The purpose of this study was to investigate whether the local use of estradiol after anterior cruciate ligament (ACL) reconstruction with a polyethylene terephthalate (PET) artificial ligament graft could promote graft-bone healing. A total of 45 New Zealand white rabbits underwent ACL reconstruction with a PET ligament graft. The experimental groups were administered a local estradiol injection at either a low dose after surgery or a high dose after surgery, and the control group did not receive an injection. Computed tomography (CT) scans and blood sample collection were routinely performed in all three groups. Over time, the serum estradiol levels increased in both experimental groups, and the CT images revealed a trend of a shrinking bone tunnel area in all three groups. The rabbits were randomly sacrificed at 2, 4, and 8 weeks after surgery. The load to failure and stiffness of the experimental groups were significantly higher than those of the control group at 4 and 8 weeks. The histological study identified more bone mineralization in the experimental groups at 4 weeks after surgery compared to the control group. This study showed that the use of estradiol is a promising approach in promoting graft-bone healing in rabbits undergoing ACL reconstruction with a PET ligament graft.

An osteogenesis/angiogenesis-stimulation artificial ligament for anterior cruciate ligament reconstruction

To solve the poor healing of polyethylene terephthalate (PET) artificial ligament in bone tunnel, copper-containing bioactive glass (Cu-BG) nanocoatings on PET artificial ligaments were successfully prepared by pulsed laser deposition (PLD). It was hypothesized that Cu-BG coated PET (Cu-BG/PET) grafts could enhance the in vitro osteogenic and angiogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and in vivo graft-bone healing after anterior cruciate ligament (ACL) reconstruction in a goat model. Scanning electron microscope and EDS mapping analysis revealed that the prepared nanocoatings had uniform element distribution (Cu, Ca, Si and P) and nanostructure. The surface hydrophilicity of PET grafts was significantly improved after depositing Cu-BG nanocoatings. The in vitro study displayed that the Cu-BG/PET grafts supported the attachment and proliferation of rBMSCs, and significantly promoted the expression of HIF-1α gene, which up-regulated the osteogenesis-related genes (S100A10, BMP2, OCN) and angiogenesis-related genes (VEGF) in comparison with PET or BG coated PET (BG/PET) grafts which do not contain Cu element. Meanwhile, Cu-BG/PET grafts promoted the bone regeneration at the graft-host bone interface and decreased graft-bone interface width, thus enhancing the bonding strength as well as angiogenesis (as indicated by CD31 expression) in the goat model as compared with BG/PET and pure PET grafts. The study demonstrates that the Cu-containing biomaterials significantly promote osteogenesis and angiogenesis in the repair of bone defects of large animals and thus offering a promising method for ACL reconstruction by using Cu-containing nanobioglass modified PET grafts.

STATEMENT OF SIGNIFICANCE

It remains a significant challenge to develop an artificial graft with distinct osteogenetic/angiogenetic activity to enhance graft-bone healing for ligament reconstruction. To solve these problems, copper-containing bioactive glass (Cu-BG) nanocoatings on PET artificial ligaments were successfully prepared by pulsed laser deposition (PLD). It was found that the prepared Cu-BG/PET grafts significantly stimulated the proliferation and osteogenic/angiogenic differentiation of bone marrow stromal cells (BMSCs) through activating HIF-1α/S100A10/Ca²⁺ signal pathway. The most important is that the in vivo bone-forming ability of Cu-containing biomaterials was, for the first time, elucidated in a large animal model, revealing the enhanced capacity of osteogenesis and angiogenesis with incorporation of bioactive Cu element. It is suggested that the copper-containing biomaterials significantly promote osteogenesis and angiogenesis in large animal defects and thus offering a promising method for ACL reconstruction by using Cu-containing nanobioglass modification of PET grafts, paving the way to apply Cu-containing biomaterials for tissue engineering and regenerative medicine.

Clinical outcomes of anterior cruciate ligament reconstruction using LARS artificial graft with an at least 7-year follow-up

The aim of our study was to assess the medium-term clinical outcomes of anterior cruciate ligament (ACL) reconstruction using the Ligament Advanced Reinforcement System (LARS) artificial ligament.A total of 168 patients who underwent arthroscopic ACL reconstruction with the LARS artificial ligament in our department were enrolled in our research. Only 125 met the inclusion/exclusion criteria, and 91 could ultimately be contacted to participate in our research. The mean follow-up was 92 ± 19 months. Physical examinations and a KT-1000 arthrometer were used to evaluate knee laxity. The International Knee Documentation Committee (IKDC) and Lysholm knee scales were evaluated for knee function. The Tegner score was tested for the condition of return to sport. Range of motion (ROM) and the rates of failure and complications were calculated.Among all patients enrolled in the study, the failure rate was 4.4%, and the overall complication rate was 2.2%. Knee laxity measured by the KT-1000 arthrometer was 1.4 ± 1.5 mm, compared with the preoperative value of 5.1 ± 1.3 mm. The Lysholm score improved from a preoperative value of 54.6 ± 14.3 to a postoperative value of 85.4 ± 12.1. The proportion of return to sport was 86.8% (79/91). The postoperative Tegner score was 4.7 ± 1.3, while its value before injury was 5.5 ± 1.0.In this study, ACL reconstruction using the LARS artificial ligament has a good prognosis with a low failure and complication rate at a mean follow-up of 91 months.

Human mesenchymal stromal cell-enhanced osteogenic differentiation by contact interaction with polyethylene terephthalate nanogratings

Among the very large number of polymeric materials that have been proposed in the field of orthopedics, polyethylene terephthalate (PET) is one of the most attractive thanks to its flexibility, thermal resistance, mechanical strength and durability. Several studies have been proposed that interface nano- or micro-structured surfaces with mesenchymal stromal cells (MSCs), demonstrating the potential of this technology for promoting osteogenesis. All these studies were carried out on biomaterials other than PET, which remains almost uninvestigated in terms of cell shaping, alignment and differentiation. Here, we study the effect of PET 350-depth nanogratings (NGs) with a ridge and lateral groove size of 500 nm (T1) or 1 μm (T2), on bone marrow-derived human MSC (hMSC) differentiation in relation to the osteogenic fate. We demonstrate that these substrates, especially T2, can promote the osteogenic phenotype more efficiently than standard flat surfaces and that this effect is more marked if cells are cultured in osteogenic medium than in basal medium. Finally, we show that the shape and disposition of calcium hydroxyapatite granules on the different substrates was influenced by the substrate symmetry, being more elongated and spatially organized on NGs than on flat surfaces.

LARS Artificial Ligament Versus ABC Purely Polyester Ligament for Anterior Cruciate Ligament Reconstruction

Background:

Graft choice for anterior cruciate ligament (ACL) reconstruction is of critical importance. Various grafts have been used so far, with autografts long considered the optimal solution for the treatment of ACL-deficient knees. Limited data are available on the long-term survivorship of synthetic grafts.

Purpose:

To compare the functional outcome and survivorship of ACL reconstructions performed using the LARS (ligament augmentation and reconstruction system) ligament and the ABC (active biosynthetic composite) purely polyester ligament.

Study Design:

Case series; Level of evidence, 4.

Methods:

The results of 72 patients who underwent primary arthroscopic ACL reconstruction with the LARS ligament and 31 cases with an ABC purely polyester ligament were reviewed. The mean follow-up periods for the LARS and ABC groups were 9.5 and 5.1 years, respectively. A survivorship analysis of the 2 synthetic grafts was performed using the Kaplan-Meier method with a log-rank test (Mantel-Cox, 95% CI). Lysholm, Tegner activity, Knee injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) scores as well as laxity measurements obtained using a KT-1000 arthrometer were recorded for all intact grafts, and a Mann-Whitney U test was used for comparison reasons.

Results:

The rupture rates for LARS and ABC grafts were 31% (95% CI, 20%-42%) and 42% (95% CI, 25%-59%), respectively. For intact grafts, the mean Lysholm score was good for both groups (90 for the LARS group and 89 for the ABC group), with the majority of patients returning to their preinjury level of activities, and the mean IKDC score was 90 for the LARS group and 86 for the ABC group.

Conclusion:

The rupture rates of both LARS and ABC grafts were both high. However, the LARS ligament provided significantly better survivorship compared with the ABC ligament at short- to midterm follow-up (95% CI).

Clinical and functional outcome after anterior cruciate ligament reconstruction using the LARS™ system at a minimum follow-up of 10 years

BACKGROUND

Since the 1980's several artificial ligaments were used for reconstruction of the anterior cruciate ligament (ACL) serving different complications. The aim of this study was to assess the clinical and functional outcomes of primary ACL reconstruction using the Ligament Augmentation Reconstruction System (LARS™) with a minimum follow-up of 10-years. The LARS™ presents a synthetic material consisting of non-absorbing polyethylene terephthalate fibres used for ligament reconstruction.

METHODS

Outcomes of 18 patients who underwent arthroscopic ACL reconstruction using the LARS™ system between 2000 and 2004 with a minimum follow-up of 10 years were observed. The International Knee Documentation Committee score (IKDC), Visual Analog Scale (VAS), Lysholm score, and Tegner Activity Scale were assessed. Clinical assessment was performed by Lachman testing, assessment of side-to-side difference on KT-2000 testing and plain radiography evaluation of osteoarthritis.

RESULTS

There were seven males and 11 females, mean age 29 years (range, 18 to 44 years) and a mean follow-up of 151.5 months. Five patients (27.8%) sustained a re-rupture of the LARS™ system and underwent revision surgery after a mean time of 23 months and four patients (22.2%) presented with a re-rupture. The average IKDC score was 76.60 ± 18.18, the average Lysholm score was 88.00 ± 10.07 and the average Tegner activity score was five at final follow-up.

CONCLUSION

Our results indicate that the LARS™ system should currently not be suggested as a potential graft for primary reconstruction of the ACL. In special cases, however, the LARS™ system can serve as an alternative graft.

Minimal Invasive Suture-Tape Augmentation for Chronic Ankle Instability

BACKGROUND

Although the modified Brostrom procedure has had excellent clinical results, postoperative complications such as skin irritation by suture material and problematic scar formation occur. This prospective study was performed to evaluate the clinical outcomes of mini-open ligament augmentation (internal brace technique) using suture tape for chronic ankle instability in a select cohort of patients.

METHODS

Thirty-four young female patients with less than 70 kg of body weight were followed for more than 2 years after suture tape augmentation for lateral ankle instability. The clinical evaluation consisted of the Foot and Ankle Outcome Score (FAOS), Foot and Ankle Ability Measure (FAAM) score, Sefton grading system, and the period to return to various activities. Measurement of talar tilt angle and anterior talar translation was obtained from stress radiographs to evaluate the longevity of mechanical ankle stability.

RESULTS

FAOS and FAAM scores had significantly improved to 92.5 points at final follow-up (P < .001). According to the Sefton grading, 31 cases (91.2%) achieved satisfactory functional results. The period to return to exercise was on average 10.2 weeks for jogging and 9.6 weeks for walking on uneven ground. The average subjective satisfaction score of patients was 93.8 points, and satisfaction with the scar was 98.5 points. Talar tilt angle and anterior talar translation had significantly improved to an average of 4.5 degrees and 4.1 mm, respectively, at final follow-up (P < .001). There were no complications such as skin irritation and wound infection, except for 1 case of chronic inflammation.

CONCLUSIONS

Minimally invasive suture tape augmentation seems to be an effective alternative for young women with chronic ankle instability. Because there is a possibility of progressive elongation over time, the longevity of mechanical ankle stability and the proper indication for using the internal brace technique should be addressed in future studies.

LEVEL OF EVIDENCE

Level IV, case series study.

Mussel-Inspired Artificial Grafts for Functional Ligament Reconstruction

The development of an artificial graft with distinct osteogenetic activity to enhance osseointegration and to induce the formation of biomimetic tissue structure for ligament reconstruction remains a significant challenge. Inspired by mussels, biomimetic calcium phosphate apatite/polydopamine hybridized-polyethylene terephthalate (APA/PDA-PET) grafts were successfully prepared. The efficacy and mechanism of APA/PDA-PET grafts to induce osseointegration were systematically investigated. The results from the in vitro study indicated that the prepared APA/PDA-PET grafts support the attachment of bone marrow stromal cells (BMSCs) and stimulate the proliferation and osteogenic/angiogenic differentiation of BMSCs via activation of the PKC/p-ERK1/2 signaling pathway. In vivo, histological and radiological results further demonstrate that the APA/PDA-PET grafts significantly improve osseointegration by inducing the formation of new bone tissue and the fibrocartilage transitional zone compared with pure PET grafts. In addition, the pull-out strength of the APA/PDA-PET grafts is significantly higher than that of the pure PET grafts 12 weeks after surgery. These results suggest that this mussel-inspired biomimetic method is an effective strategy for modifying artificial grafts, and the prepared APA/PDA-PET grafts, which possess a beneficial interface, can significantly improve in vivo osseointegration for ligament reconstruction via the synergistic effect of polydopamine and apatite.

Surface modification of nano-silica on the ligament advanced reinforcement system for accelerated bone formation: primary human osteoblasts testing in vitro and animal testing in vivo

The Ligament Advanced Reinforcement System (LARS) has been considered as a promising graft for ligament reconstruction. To improve its biocompatibility and effectiveness on new bone formation, we modified the surface of a polyethylene terephthalate (PET) ligament with nanoscale silica using atom transfer radical polymerization (ATRP) and silica polymerization. The modified ligament is tested by both in vitro and in vivo experiments. Human osteoblast testing in vitro exhibits an ∼21% higher value in cell viability for silica-modified grafts compared with original grafts. Animal testing in vivo shows that there is new formed bone in the case of a nanoscale silica-coated ligament. These results demonstrate that our approach for nanoscale silica surface modification on LARS could be potentially applied for ligament reconstruction.

Synthetic devices for reconstructive surgery of the cruciate ligaments: a systematic review

PURPOSE

The role of synthetic devices in the management of the cruciate ligament-injured knee remains controversial. The aim of this systematic review was to assess the safety and efficacy of synthetic devices in cruciate ligament surgery.

METHODS

A systematic review of the electronic databases Medline, Embase, and The Cochrane Library (issue 1, 2014) on January 13, 2014, was performed to identify controlled and uncontrolled trials. Trials that assessed the safety and efficacy of synthetic devices for cruciate ligament surgery were included. The main variables assessed included rates of failure, revision, and noninfective effusion and synovitis. Patient-reported outcome assessments and complications were also assessed where reported.

RESULTS

From 511 records screened, we included 85 articles published between 1985 and 2013 reporting on 6 synthetic devices (ligament augmentation and reconstruction system [Ligament Augmentation and Reconstruction System (LARS; Surgical Implants and Devices, Arc-sur-Tille, France)]; Leeds-Keio [Xiros (formerly Neoligaments), Leeds, England]; Kennedy ligament augmentation device [3M, St Paul, MN]; Dacron [Stryker, Kalamazoo, MI]; Gore-Tex [W.L. Gore and Associates, Flagstaff, AZ]; and Trevira [Telos (limited liability company), Marburg, Germany]). The heterogeneity of the included studies precluded meta-analysis. The results were analyzed by device and then type of reconstruction (anterior cruciate ligament [ACL]/posterior cruciate ligament [PCL]/combined ACL and PCL). The lowest cumulative rates of failure were seen with the LARS device (2.6% for ACL and 1% for PCL surgery). The highest failure rate was seen in the Dacron ACL group (cumulative rate, 33.6%). Rates of noninfective synovitis and effusion ranged from 0.2% in the LARS ACL group to 27.6% in the Gore-Tex ACL group. Revision rates ranged from 2.6% (LARS) to 11.8% (Trevira-Hochfest; Telos). Recent designs, specifically the LARS, showed good improvement in the outcome scores. The mean preoperative and postoperative Lysholm knee scores were 54 and 88, respectively; the mean preoperative and postoperative Tegner activity scale scores were 3.3 and 6, respectively.

CONCLUSIONS

Preliminary results for newer-generation devices, specifically the LARS, show lower reported rates of failure, revision, and sterile effusion/synovitis when compared with older devices.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II through IV studies.

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.

A comparison of acute and chronic anterior cruciate ligament reconstruction using LARS artificial ligaments: a randomized prospective study with a 5-year follow-up

PURPOSE

This prospective randomized study compared acute and chronic anterior cruciate ligament (ACL) reconstruction using ligament advanced reinforcement system (LARS) artificial ligament in young active adults with a 5-year follow-up.

METHODS

Fifty-five patients were enrolled in this study and divided into two groups based on the elapsed time between the injury and reconstruction: the acute group (3-7 weeks) and the chronic group (6-11 months). The clinical outcomes were evaluated using the Lysholm knee scoring scale, the Tegner activity rating, a KT-1000 Arthrometer, and the International Knee Documentation Committee (IKDC) scoring system. Isokinetic strength of the quadriceps and hamstring was assessed using the Biodex System 3 isokinetic dynamometer.

RESULTS

Anterior laxity was decreased and quadriceps/hamstring muscle strength was increased in the acute group compared to the chronic group (p > 0.05). There were no statistically significant differences in Lysholm scores, Tegner activity scores, and the IKDC evaluation form between the two groups.

CONCLUSIONS

These results suggest that earlier ACL reconstruction using a LARS artificial ligament may provide an advantage in the treatment and rehabilitation of ACL rupture.

Biomedical coatings on polyethylene terephthalate artificial ligaments

This review comprehensively covers research conducted to enhance polyethylene terephthalate (PET) artificial ligament osseointegration in the bone tunnel. These strategies, using biocompatible or bioactive coatings, had a positive effect in promoting PET ligament osseointegration by increasing bone formation and decreasing fibrous scar tissue at the ligament-to-bone interface. The improved osseointegration can be translated into a significant increase in the biomechanical pull-out loads. However, the load-to-failure of coated ligament is far lower than that of native ACL. Coatings to promote intra-articular ligamentization are also discussed in this study. Collectively, our investigations may arouse further study of the biological coating of PET artificial ligaments in order to effectively enhance ligament osseointegration and promote artificial ligament ligamentization.