Histological and radiographic evaluation of three common tendon transfer techniques in an un-ossified bone porcine model: Implications for early anterior tibialis tendon transfers in children with clubfeet

Abstract

Purpose To compare the histological healing and radiographic effects of tendons transferred to ossified or unossified bone using different tendon fixation techniques Methods Nine new-born piglets underwent bilateral tendon transfers to either the ossified boney calcaneal body or unossified apophysis. The tendons were fixed using metallic suture anchors, sutures alone or a bone tunnel. At six weeks of age, calcanei were harvested, radiologically imaged and then prepared for histology. A semi-quantitative aggregated scoring system with values ranging from 0 (poor) to 15 (excellent), was used to grade healing at the surgical enthesis and the apophyseal ossification was graded by five independent reviewers in triplicate using a modified (1 to 4) validated scoring system. Results Histologically, the cartilaginous transfers utilizing the tunnel and suture techniques also demonstrated the best average aggregated scores of entheses healing rivalling that measured in transfers using the classic bone tunnel technique (clinical benchmark), whereas suture anchor fixation demonstrated the worst healing in both the ossified and unossified samples. All three transfer techniques caused at least minor alterations in apophyseal ossification, with the most significant changes observed in the metallic suture anchor cohort. The tunnel and suture techniques demonstrated similar and more mild abnormalities in ossification. Conclusion Tendon transfers to unossified bone heal histologically as well as transfers classically performed through tunnels in bone. Suture fixation or tunnel techniques appear radiographically and histologically superior to suture anchors in our newborn porcine model. Level of evidence

Tibialis anterior tendon transfer using bone anchor for dynamic supination in congenital talipes equinovarus

“…Methods using a metallic suture anchor, sutures alone or a bone tunnel were compared. They found that on histology, suture anchor fixation demonstrated the worst healing in both the ossified and unossified samples with minor alterations in apophyseal ossification seen with all methods, with the most significant changes observed in the metallic suture anchor cohort [13]. The youngest patient in our cohort was 3.4 years.…”

“…There has been limited investigation into the comparative efficacy of the different methods of tibialis anterior docking in children. Halanski et al [18] and Korth et al [13] have published similar work regarding the effect of the transfer on subsequent bone growth and the different pullout strengths of three techniques in unossified porcine bone [13,15]. Halanski et al [18] drilled a tunnel using an 18 gauge needle in the bony or cartilaginous portion of the calcaneus of 25 piglets.…”

“…Korth et al . [13] also used ossified and unossified piglet calcanei to investigate different tendon fixation techniques, with both histological and radiographic outcome measures. Methods using a metallic suture anchor, sutures alone or a bone tunnel were compared.…”

“…Our cohort does not support the results found by Korth et al . [13]; the disparity may be due to their small sample size (three anchors in bone and three anchors in cartilage). One of the aims of the work of Korth et al .…”

“…Breaching the plantar skin may have implications with skin irritation and infection, as well as posing risk to plantar nerves [7]. Since the introduction of this technique, there have been multiple modifications including the method of anchoring the tendon [8][9][10][11][12][13][14][15]. However, there have been no studies showing the clinical results of the use of a bone anchor to secure the tendon without drilling through the lateral cuneiform bone when compared with the more traditional Garceau method [7].…”