Enhancement of tendon–bone healing via the combination of biodegradable collagen-loaded nanofibrous membranes and a three-dimensional printed bone-anchoring bolt

Abstract

A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA) bolt as the bone anchor and a poly(d,l-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon–bone interface integration. Degradation rate and compres-sive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/ collagen nanofibers and PLA bolts for tendon–bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon–bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon–bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction.