Role of tissue engineered collagen based tridimensional implant on the healing response of the experimentally induced large Achilles tendon defect model in rabbits: a long term study with high clinical relevance

Abstract

BackgroundTendon injury is one of the orthopedic conditions poses with a significant clinical challenge to both the surgeons and patients. The major limitations to manage these injuries are poor healing response and development of peritendinous adhesions in the injured area. This study investigated the effectiveness of a novel collagen implant on tendon healing in rabbits.ResultsSeventy five mature White New-Zealand rabbits were divided into treated (n = 55) and control (n = 20) groups. The left Achilles tendon was completely transected and 2 cm excised. The defects of the treated animals were filled with collagen implants and repaired with sutures, but in control rabbits the defects were sutured similarly but the gap was left untreated. Changes in the injured and normal contralateral tendons were assessed weekly by measuring the diameter, temperature and bioelectrical characteristics of the injured area. Clinical examination was done and scored. Among the treated animals, small pilot groups were euthanized at 5, 10, 15, 20, 30, 40 and 60 (n = 5 at each time interval) and the remainder (n = 20) and the control animals at 120 days post injury (DPI). The lesions of all animals were examined at macroscopic and microscopic levels and the dry matter content, water delivery and water uptake characteristics of the lesions and normal contralateral tendons of both groups were analyzed at 120 DPI.No sign of rejection was seen in the treated lesions. The collagen implant was invaded by the inflammatory cells at the inflammatory phase, followed by fibroplasia phase in which remnant of the collagen implant were still present while no inflammatory reaction could be seen in the lesions. However, the collagen implant was completely absorbed in the remodeling phase and the newly regenerated tendinous tissue filled the gap. Compared to the controls, the treated lesions showed improved tissue alignment and less peritendinous adhesion, muscle atrophy and fibrosis. They also showed significantly better clinical scoring, indices for water uptake and water absorption, and bioelectrical characteristics than the controls.ConclusionThis novel collagen implant was biodegradable, biocompatible and possibly could be considered as a substitute for auto and allografts in clinical practice in near future.

Tendon and Ligament Tissue Engineering, Healing and Regenerative Medicine

“…In this condition, the continuity of the tissue in not completely lost [33]. Finally, in the third degree, total collagen fibers and bundles are ruptured and a considerable gap occurs between the edges [25][26][27][28][29]. Treatment of grade one is non-surgical and is limited to supportive strategies; however there is no well accepted method for managing grade two injuries (surgical vs. non-surgical) and in grade three (total rupture), in most instances the ruptured tissue should be surgically repaired [12,29].…”

“…In such conditions it is often necessary to resect the remaining tendon and this results in gap formation [12,29]. The gap should be surgically reconstructed and if it is neglected then joint stiffness occurs which impairs the functionality of the injured limb [26]. Despite of recent advances in orthopedic techniques, however reconstruction of such large and massive tissue defects is technically demanding and variation in surgical techniques in repairing such tissue defects are remarkable and mostly it is hard for surgeons to choose the method of choice [12,26,29].…”

“…The gap should be surgically reconstructed and if it is neglected then joint stiffness occurs which impairs the functionality of the injured limb [26]. Despite of recent advances in orthopedic techniques, however reconstruction of such large and massive tissue defects is technically demanding and variation in surgical techniques in repairing such tissue defects are remarkable and mostly it is hard for surgeons to choose the method of choice [12,26,29]. Many different surgical techniques exist, but only a few of them have been validated in a strict scientific manner [13][14][15][16][17][18][19][20][21].…”

“…Using autografts is currently the only gold standard method for managing large tendon and ligament deficits [26,29]. However, reconstruction of such large defects requires massive tissue harvesting from the donor site and therefore the donor site morbidity and pain is a considerable challenge to autografts [3,[12][13][14].…”

“…All these available options have their own significant limitations [3]. Tissue engineering is a newer option and is divided into four categories of scaffold, healing promotive factors, stem cells and gene therapy [22][23][24][25][26][27][28][29][30][31][32]. Using each or a combination of them have provided the new insights in orthopedic surgery [12,24,[30][31][32].…”