Differential growth on sutures of tendon cells derived from torn human rotator cuff
Rotator cuff tendon pathology is proposed to account for 30-70% of all shoulder pain and surgical repair with a nonabsorbable suture is the common option for painful rotator cuff tears that have failed conservative treatment. A number of studies have suggested the beneficial effect of augmenting the repair with implants constructed from polymers used for sutures. Thus, it was of interest to investigate the affinity of tendon-derived fibroblasts, often thought to be the repairing agents of torn tendons, to commonly used sutures. The aim of this comparative study was to evaluate the suitability of these sutures for the construction of a patch by measuring cell survival, proliferation, and migration of human tendon-derived fibroblasts on different sutures. To ensure relevance to the target tissue, cells used in this study were obtained from torn human supraspinatus tendons. An initial comparison of cell proliferation on suture mats showed an overall positive proliferation on polyester (Ethibond) and polydioxanone (PDSII) mats and a reduction of proliferation on vicryl (polyglactin 910) compared to day one. The results also showed that the degradation products of vicryl had a negative effect on cell growth over 10 weeks. Of the commercial sutures selected and tested, Ethibond showed the best performance in terms of cell attachment and increase in biomass. The degradable PDSII also showed good interaction with cells in vitro, but relatively poor cell adhesion. This study provides useful and clinically relevant information, which could help to guide future considerations for candidate materials from which to construct tissue repair patches.
Available from: Osnat Hakimi
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ABSTRACT: Rotator cuff tendon pathology is thought to account for 30-70 % of all shoulder pain. For cases that have failed conservative treatment, surgical re-attachment of the tendon to the bone with a non-absorbable suture is a common option. However, the failure rate of these repairs is high, estimated at up to 75 %. Studies have shown that in late disease stages the tendon itself is extremely degenerate, with reduced cell numbers and poor matrix organisation. Thus, it has been suggested that adding biological factors such as platelet rich plasma (PRP) and mesenchymal stem cells could improve healing. However, the articular capsule of the glenohumeral joint and the subacromial bursa are large spaces, and injecting beneficial factors into these sites does not ensure localisation to the area of tendon damage. Thus, the aim of this study was to develop a biocompatible patch for improving the healing rates of rotator cuff repairs. The patch will create a confinement around the repair area and will be used to guide injections to the vicinity of the surgical repair. Here, we characterised and tested a preliminary prototype of the patch utilising in vitro tools and primary tendon-derived cells, showing exceptional biocompatibility despite rapid degradation, improved cell attachment and that cells could migrate across the patch towards a chemo-attractant. Finally, we showed the feasibility of detecting the patch using ultrasound and injecting liquid into the confinement ex vivo. There is a potential for using this scaffold in the surgical repair of interfaces such as the tendon insertion in the rotator cuff, in conjunction with beneficial factors.
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ABSTRACT: The use of rotator cuff augmentation has increased dramatically over the last 10 years in response to the high rate of failure observed after non-augmented surgery. However, although augmentations have been shown to reduce shoulder pain, there is no consensus or clear guideline as to what is the safest or most efficacious material. Current augmentations, either available commercially or in development, can be classified into three categories: non-degradable structures, extra cellular matrix (ECM)-based patches and degradable synthetic scaffolds. Non-degradable structures have excellent mechanical properties, but can cause problems of infection and loss of integrity in the long-term. ECM-based patches usually demonstrate excellent biological properties in vitro, but studies have highlighted complications in vivo due to poor mechanical support and to infection or inflammation. Degradable synthetic scaffolds represent the new generation of implants. It is proposed that a combination of good mechanical properties, active promotion of biological healing, low infection risk and bio-absorption are the ideal characteristics of an augmentation material. Among the materials with these features, those processed by electrospinning have shown great promis. However, their clinical effectiveness has yet to be proven and well conducted clinical trials are urgently required.
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ABSTRACT: BACKGROUND:Severe chronic lateral epicondylitis (LE) is associated with degenerative tendon changes, extracellular matrix breakdown, and tendon cell loss. On the basis of positive outcomes from preclinical studies, this study is the first clinical trial of autologous tenocyte injection (ATI) on severe tendinopathy associated with chronic LE. HYPOTHESIS:Autologous tenocyte injection is a safe and effective procedure that enables a reduction in pain and improvement in function in resistant LE. STUDY DESIGN:Case series; Level of evidence, 4. METHODS:Patients with severe refractory LE underwent clinical evaluation and magnetic resonance imaging (MRI) before intervention. A patellar tendon needle biopsy was performed under local anesthetic, and tendon cells were expanded by in vitro culture. Tenocytes used for the injection were characterized by flow cytometry and real-time polymerase chain reaction. Autologous tenocytes were injected into the site of tendinopathy identified at the origin of the extensor carpi radialis brevis tendon under ultrasound guidance on a single occasion. Patients underwent serial clinical evaluations and repeat MRI at 12 months after intervention. RESULTS:A total of 20 consecutive patients were included in the study. Three patients withdrew consent after enrollment and before ATI. No adverse event was reported at either biopsy or injection sites. Furthermore, no infection or excessive fibroblastic reaction was found in any patient at the injection site. Clinical evaluation revealed an improvement in mean visual analog scale scores, for a maximum pain score from 5.94 at the initial assessment to 0.76 at 12 months (P < .001). Mean quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) and grip strength scores also significantly improved over the 12-month follow-up (QuickDASH score, 45.88 [baseline] to 3.84; grip strength, 20.17 kg [baseline] to 37.38 kg; P < .001). With use of a validated MRI scoring system, the grade of tendinopathy at the common extensor origin improved significantly by 12 months (P < .001). One patient elected to proceed to surgery 3 months after ATI following a reinjury at work. CONCLUSION:In this study, patients with chronic LE who had previously undergone an unsuccessful full course of nonoperative treatment showed significantly improved clinical function and structural repair at the origin of the common extensor tendon after ATI. This novel treatment is encouraging for the treatment of tendinopathy and warrants further evaluation.
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