Surface Treatment of Flexor Tendon Autograft and Allograft Decreases Adhesion Without an Effect of Graft Cellularity: A Pilot Study

Abstract

Background Flexor tendon grafting is often required to reconstruct a failed tendon repair. Previous reports have demonstrated flexor grafts coated with lubricants such as carbodiimide derivatized hyaluronic acid (cd-HA) decrease adhesion formation and improve digit function. However, whether this surface modification would affect graft adhesion and cellularity is unknown. Questions/Purposes Adhesion score and the cellularity of the graft of untreated and cd-HA surface-modified autograft and allograft tendons were studied using a canine forepaw in vivo model. Methods The peroneus longus tendons (n = 6) and flexor digitorum profundus tendons (n = 8) were used as extrasynovial autograft and intrasynovial allograft, respectively. The flexor digitorum profundus (FDP) tendons in the second and fifth digits in each dog were reconstructed with one digit treated with cd-HA and the other treated with saline as a control. Six weeks after surgery, the grafted tendons were harvested for histological evaluation with hematoxylin and eosin staining. During dissection, the adhesions were observed and scored. Results The adhesion score was greatest in the extrasynovial autograft without surface modification and the least in the intrasynovial allograft with surface modification. Autograft tendons had a higher cell density than the allografts regardless of surface treatment. Cd-HA graft treatment did not affect cellularity when compared with controls. Conclusions Our observations suggest surface modification of a tendon graft with cd-HA decreased the adhesion formation without altering the cellularity in either autologous or allograft tendon. We therefore presume this surface modification would not adversely affect graft healing.

Repopulation of Intrasynovial Flexor Tendon Allograft with Bone Marrow Stromal Cells: AnEx VivoModel

“…Karabekmez and Zhao reported that surface modification with cd-HA decreased the adhesion formation without altering the cellularity in either the autologous extrasynovial tendon or the intrasynovial allograft in an in vivo canine model. 50 In the current study, the surface modification also restored tendon gliding resistance to that of normal tendon over 1000 cycles.…”

“…As a result, it is clear if this treatment would affect cell seeding and fate, although Karabekmez reported that this surface treatment did not impair the cellularity of either the autograft or allograft in an in vivo canine model. 50 Fifth, we were unable to successfully evaluate all tensile properties to midsubstance failure, as some specimens slipped at the grips before tensile failure. Tensile properties were analyzed from the linear portion of the stress-strain curve variable failure mode.…”

The Effects of Biological Lubricating Molecules on Flexor Tendon Reconstruction in a Canine Allograft Model In Vivo

“…The graft tendon within the flexor sheath and adhesions around the graft were assessed by two investigators who were blinded to treatment status (CZ and RLK), with an adhesion score ranging from 0 (no adhesions) to 8 (very severe adhesions) as described previously. 30 Any disagreements in adhesion score were resolved by consensus.…”

The past, present and future in scaffold-based tendon treatments

“…For example, in a canine model, HA functionalised allografts demonstrated significant reduction in adhesions, without any negative effect in cellularity and mechanical properties [317,318], whilst HA pre-treatment in a rabbit ACL model demonstrated mechanical integrity maintenance and improved healing [319]. Separate studies investigating the effect of the addition of HA molecules to the surface of allografts in canine models found that adhesions to surrounding tissue, were reduced when HA was used 6 weeks post-surgery, and that HA had no effect on the cellularity of tissues after removal or overall tissue mechanical properties [317,318]. This has been confirmed in the rabbit model [319].…”