Initial stability of two different adhesives compared to suture repair for acute Achilles tendon rupture--a biomechanical evaluation

Mechanically Competent Chitosan-Based Bioadhesive for Tendon-to-Bone Repair

Current suture-based surgical techniques used to repair torn rotator cuff tendons do not result in mechanically competent tendon-to-bone attachments, leading to high postoperative failure rates. Although adhesives have been proposed to protect against sutures tearing through tendon during healing, no currently available adhesive meets the clinical needs of adhesive strength, biocompatibility, and promotion of healing. Here, a biocompatible, graded, 3,4-dihydroxy phenyl chitosan (BGC) bioadhesive designed to meet these needs is presented. Although 3,4-dihydroxy phenyl chitosan (DP-chitosan) bioadhesives are biocompatible, their adhesion strength is low; soluble oxidants or cross-linking agents can be added for higher bonding strength, but this sacrifices biocompatibility. These challenges are overcome by developing a periodate-modified ion exchange resin-bead filtration system that oxidizes catechol moieties to quinones and filters off the activating agent and resin. The resulting BGC bioadhesive exhibited sixfold higher strength compared to commercially available tissue adhesives, with strength in the range necessary to improve tendon-to-bone repair (≈1MPa, ≈20% of current suture repair strength). The bioadhesive is biocompatible and promoted tenogenesis; cells exposed to the bioadhesive demonstrated enhanced expression of collagen I and the tenogenic marker Scx. Results demonstrated that the bioadhesive has the potential to improve the strength of a tendon-to-bone repair and promote healing.

Bioadhesives for musculoskeletal tissue regeneration

Natural or synthetic materials designed to adhere to biological components, bioadhesives, have received significant attention in clinics and surgeries. As a result, there are several commercially available, FDA-approved bioadhesives used for skin wound closure, hemostasis, and sealing tissue gaps or cracks in soft tissues. Recently, the application of bioadhesives has been expanded to various areas including musculoskeletal tissue engineering and regenerative medicine. The instant establishment of a strong adhesion force on tissue surfaces has shown potential to augment repair of connective tissues. Bioadhesives have also been applied to secure tissue grafts to host bodies and to fill or seal gaps in musculoskeletal tissues caused by injuries or degenerative diseases. In addition, the injectability equipped with the instant adhesion formation may provide the great potential of bioadhesives as vehicles for localized delivery of cells, growth factors, and small molecules to facilitate tissue healing and regeneration. This review covers recent research progress in bioadhesives as focused on their applications in musculoskeletal tissue repair and regeneration. We also discuss the advantages and outstanding challenges of bioadhesives, as well as the future perspective toward regeneration of connective tissues with high mechanical demand.

Interlocking horizontal mattress suture versus Kakiuchi technique in repair of Achilles tendon rupture: a biomechanical study

BACKGROUND

In recent years, the type of surgical treatment for Achilles tendon rupture has been the subject of controversial debate. This biomechanical study evaluates for the first time in literature the ultimate failure load (UFL) of interlocking horizontal mattress (IHM) suture as compared with Kakiuchi suture in Achilles tendon rupture. The hypothesis is that IHM suture can be performed also for Achilles tendon rupture and ensures higher resistance compared with the traditional Kakiuchi suture.

MATERIALS AND METHODS

Twenty fresh bovine Achilles tendons were obtained. Ten preparations were randomly assigned to each of two different groups: group A (10 specimens) sutured by IHM technique, and group B (10 specimens) sutured by Kakiuchi technique. Each construct was mounted and fixed on a tensile testing machine. Static preconditioning of 50 N was applied for 5 min as initial tensioning to stabilize the mechanical properties of the graft, then a load to failure test was performed at crosshead speed of 500 mm/min.

RESULTS

Ten specimens were tested for each group. The mean UFL was 228.6 ± 98.6 N in the IHM suture group and 96.57 ± 80.1 N in the Kakiuchi suture group. Statistical analysis showed a significant difference (p < 0.05) with better UFL in the IHM group. In both groups, the failure mode registered in each specimen was suture breakage (rupture of suture thread).

CONCLUSIONS

IHM suture achieved better UFL compared with Kakiuchi suture in an animal model of Achilles tendon repair. These results seem to support IHM as a valid option in Achilles tendon rupture.

Different Sutures in the Surgical Treatment of Acute Closed Achilles Tendon Rupture

The aim was to compare the postoperative efficacy of the PDS II and Ethibond W4843 sutures in fresh, closed Achilles tendon rupture. With methods of random grouping (level of evidence II b), a total of 128 patients with fresh Achilles tendon rupture were operated on with PDS II or Ethibond W4843 suture. Postoperative objective examination and the American Orthopaedic Foot & Ankle Society (AOFAS) scoring system were used for the evaluation. Group A underwent 12-39 months of follow-up, for an average of 22 months. Group B underwent 12-37 months of follow-up, for an average of 23 months. The postoperative AOFAS score of group A within 3 months was 93 ± 9.6 points. One case exhibited re-rupture, five cases exhibited incision infection, one case manifested deep infection, and seven cases exhibited Achilles tendon adhesion. The postoperative AOFAS score of group B within 3 months was 97 ± 7.8 points. Eleven cases had incision infection, and 13 cases manifested Achilles tendon adhesion. Minimal differences were observed in the incision infection, re-rupture rate, and Achilles tendon adhesion in the study of the PDS II and Ethibond W4843 sutures. But, based on the AOFAS score and pain score, the Ethibond suture performed better.

Surgical adhesive BioGlue™ does not benefit tendon repair strength: an ex vivo study

Surgical adhesives are useful supplements in surgery, but their benefit in tendon repair is uncertain. The purpose of this study was to evaluate the effect of BioGlue™ on strength of flexor tendon repair. A total of 60 porcine flexor tendons were divided into three groups. In group one, a conventional core and peripheral suture repair was used. In group two, a core suture and BioGlue™ were used. In group three, a conventional core and peripheral suture repair and BioGlue™ were used. We performed static and cyclic axial load testing and measured diameter of the repair site. We found that BioGlue™ did not improve the tensile strength when added to a core and peripheral suture and that there was an increase in bulk at the repair site. We conclude that BioGlue™ application cannot replace a peripheral suture as tensile strength significantly decreases without a peripheral suture, and it does not benefit a tendon already repaired with a core and peripheral suture.

LEVEL OF EVIDENCE

n/a.

Is percutaneous suturing superior to open fibrin gluing in acute Achilles tendon rupture?

PURPOSE

Open fibrin gluing is reported to enable anatomical reconstruction with less soft tissue compromise than suture repair. Our main objective was to compare the complication rate, function, pain and disability of the two operative approaches of percutaneous suture using the Paessler technique and open fibrin gluing.

METHODS

Sixty-four patients (two centres, retrospective cohort study, 2000-2009) who had undergone acute Achilles tendon repair with either percutaneous suture (n = 27; 44 years) or open fibrin glue (n = 37; 45 years) took part in a follow-up examination after a median of 63 months (range, six to 180). Ankle range of motion, calf and ankle circumferences and return to work and sports activities were evaluated. Isokinetic und sonographic evaluation results were retrieved.

RESULTS

Complications were noted in 22 patients (34 %). Delayed wound healing without evidence of surgical site infection was found in three patients in the fibrin group and two patients in the suture group. Postoperative scar tenderness described as pain at the rim of the shoe was significantly more frequent in the suture group (p = 0.03). Re-rupture requiring re-operation occurred in one patient. Transient paresthesia of the heel occurred in 12 patients. No sural nerve lesions were reported. There was no significant difference between groups regarding lower leg circumference, disability, or function. Ultrasound and isokinetic measurements did not reveal a significant difference between the two methods.

CONCLUSIONS

The present study suggests that open fibrin gluing is a reasonable alternative to percutaneous repair of acute ruptures of the Achilles tendon and both techniques can yield reliably good results.

Functional evaluation of professional athletes treated with a mini-open technique for achilles tendon rupture

INTRODUCTION

in this study we report the functional results of 36 professional athletes treated with a combined percutaneous and mini-open technique.

METHODS

patients were evaluated with Victorian Institute of Sports Assessment-Achilles questionnaire (VISA-A), the objective 100-points Hannover scale and the Ergo-jump Bosco System device.

RESULTS

at a mean 28- month follow-up no re-rupture cases were observed. Six patients had minor complications. The Ergo-jump Bosco System device showed no significant differences in the side-to-side evaluation in regard to strength (-0.94%) and elasticity (+2.44%), while a significant post-operative loss was detected in the endurance trials (-6.78%). The Hannover scale showed an average score of 94.5, while the VISA-A had an average of 93.1. Thirty-one patients resumed their pre-operative sports activity level within five months from surgery.

CONCLUSIONS

our results showed that the combined mini-open and percutaneous repair is an effective treatment for professional athletes, with satisfactory clinical and functional results, lack of major complications and a quick return to professional sports activity.

Current state and use of biological adhesives in orthopedic surgery

Bone and tissue adhesives are common and beneficial supplements to standard methods of musculoskeletal tissue suture repair. Knowledge and development of biologically derived or inspired adhesives useful in orthopedic surgery are rapidly advancing. Recent literature demonstrates the increased adjunct or primary use of biological adhesives in the repair of musculoskeletal soft tissues, chondral fractures, and osteochondral fractures. Adhesives offer more benefits and enhancements to tissue healing than current fixation methods afford, including improved biocompatibility, resorbability, and non-immunogenicity. Further investigation is required to determine the extent of the role that these bioadhesives can play in orthopedic surgery. The largest group of biologically derived adhesives and sealants is fibrin sealants, which include first- and second-generation commercially available fibrin sealants, autologous fibrin sealants, and variants. Other groups include gelatin-resorcin aldehydes, protein-aldehyde systems, collagen-based adhesives, polysaccharide- based adhesives, mussel adhesive proteins, and various biologically inspired or biomimetic glues. Potential uses include applications in orthopedic-related blood conservation, arthroplasty, articular cartilage disorders, sports medicine, spine surgery, trauma, and tumors. The development of an adhesive with universal application is likely unfeasible, given the unique characteristics of various musculoskeletal tissues. However, the literature demonstrates the overall underuse of adhesives and indicates the rising probability of the development of a successful variety of bioadhesives for use in orthopedic surgery. As a result of reading this article, physicians should be able to: 1. Describe the difference between adhesives and sealants. 2. Recognize fibrin adhesives commonly used in practice today and identify other biological adhesives with rising potential. 3. Analyze how fibrin sealants work relative to fibrin and fibrinogen. 4. Identify anatomical areas and techniques in which fibrin sealants are used.

Development of a surgically optimized graft insertion suture technique to accommodate a tissue-engineered tendon in vivo

The traumatic rupture of tendons is a common clinical problem. Tendon repair is surgically challenging because the tendon often retracts, resulting in a gap between the torn end and its bony insertion. Tendon grafts are currently used to fill this deficit but are associated with potential complications relating to donor site morbidity and graft necrosis. We have developed a highly reproducible, rapid process technique to manufacture compressed cell-seeded type I collagen constructs to replace tendon grafts. However, the material properties of the engineered constructs are currently unsuitable to withstand complete load bearing in vivo. A modified suture technique has been developed to withstand physiological loading and off load the artificial construct while integration occurs. Lapine tendons were used ex vivo to test the strength of different suture techniques with different sizes of Prolene sutures and tissue-engineered collagen constructs in situ. The data were compared to standard modified Kessler suture using a standard tendon graft. Mechanical testing was carried out and a finite element analysis stress distribution model constructed using COMSOL 3.5 software. The break point for modified suture technique with a tissue-engineered scaffold was significantly higher (50.62 N) compared to a standard modified Kessler suture (12.49 N, p<0.05). Distributing suture tension further proximally and distally from the tendon ends increased the mechanical strength of the repairs. We now have ex vivo proof of concept that this suture technique is suitable for testing in vivo, and this will be the next stage of our research.

Novel application of a tissue-engineered collagen-based three-dimensional bio-implant in a large tendon defect model: a broad-based study with high value in translational medicine

This study was designed to investigate the effectiveness of a novel tissue-engineered three-dimensional collagen implant on healing of a large tendon-defect model, in vivo. Forty rabbits were divided into two equal groups: treated and control. A 2cm full-thickness gap was created in the left Achilles tendons of all the rabbits. To maintain the gap at the desired length (2cm), a Kessler suture was anchored within the proximal and distal ends of the remaining tendon. In the treated group a collagen implant was inserted in the gap while in the control group the gap was left unfilled. At weekly intervals the animals were examined clinically and their Achilles tendons tested bioelectrically. The hematological parameters and the serum Platelet-Derived Growth Factor of the animals were analyzed at 60 days post injury (DPI) immediately prior to euthanasia. Their injured (left) and normal contralateral Achilles tendons were harvested and examined at gross morphologic level before being subjected to biomechanical testing, and biophysical and biochemical analysis. The treated animals showed superior weight-bearing and greater physical activity than their controls. New dense tendinous tissue with a transverse diameter comparable to that of intact tendons filled the defect area of the treated tendons and had entirely replaced the collagen implant, at 60 DPI. In control lesions the defect was filled with loose areolar connective tissue similar to subcutaneous fascia. Treatment significantly improved the electrical resistance, dry matter, hydroxyproline content, water uptake and water delivery characteristics, of the healing tissue, as well as maximum load, yield load, maximum stress, yield stress and modulus of elasticity of the injured treated tendons compared to those of the control tendons (P<0.05). Use of this three-dimensional collagen implant improved the healing of large tendon defects in rabbits.

Efficacy and complications of open and minimally invasive surgery in acute Achilles tendon rupture: a prospective randomised clinical study--preliminary report

PURPOSE

Surgical treatment of an acute Achilles tendon rupture can effectively reduce the risk of re-rupture, but it increases the probability of surgical complications. We postulated that a minimally invasive surgical treatment might reduce the number of complications related to open surgery and improve the functional results.

METHOD

We enrolled 47 patients with acute Achilles tendon ruptures in a prospective, randomised trial to compare clinical results and complications between a minimally invasive procedure with the Achillon(®) device and traditional open surgery with Krackow-type sutures. The average patient age was 46 years. The follow up time was 24 months.

RESULTS

No Achilles tendon re-rupture or nerve injury occurred in treated patients. There were two cases of wound infections in the open surgery group, and one superficial wound infection occurred in the minimally invasive group. The groups were not significantly different in the amount of pain, range of ankle movements, the single heel-rise test, calf circumference, or time to return to work and sports.

CONCLUSION

After a two year follow-up period, we found no significant differences in clinical outcomes between groups treated with traditional open surgery or minimally invasive surgery.

Medial Achilles tendon island flap--a novel technique to treat reruptures and neglected ruptures of the Achilles tendon

PURPOSE

There is a strong consensus for surgical treatment of reruptures and neglected ruptures of the Achilles tendon. A number of different surgical techniques have been described and several of these methods include extensive surgical exposure to the calf and technically demanding tendon transfers. The overall risk of complications is high and in particular the risk for wound healing problems, which are triggered by an increased tension in the skin when inserting a bulky graft to cover the rupture. In order to reduce the risk for wound healing problems a new, less complicated surgical technique was developed, as described in this study.

METHODS

Nine consecutive patients (including six chronic ruptures and three reruptures) with complicating co-morbidities and with a tendon defect between three and eight centimetres were operated upon using the described novel technique. Patient-reported functional outcome was reported after two to eight years.

RESULTS

All tendon defects were successfully repaired. Neither early nor late surgical complications occurred. High patient satisfaction was reported for all patients.

CONCLUSIONS

The new surgical technique with a medial Achilles tendon island flap seems to be safe and results in a good patient reported outcome.