Impact of combinatory growth factor application on rabbit Achilles tendon injury with operative versus conservative treatment: A pilot study

Acute Achilles tendon (AT) rupture is a common injury with a comparatively high complication rate. Presently, surgical treatments compete with nonoperative treatment modalities. The aim of this study was to elucidate the possible beneficial effects of short-term combinatory application of growth factors on tendon healing during operative or conservative treatment. In this controlled laboratory study, the left ATs of 40 adult New Zealand White rabbits were transected and either sutured or treated conservatively. Half of the animals from each treatment modality group repetitively received a mixture of VEGF165, bFGF, and rPDGF which was administered peritendineally. The left legs were immobilized with external fixateurs for 6 weeks. The ATs were harvested 3 months after intervention. Tensile strength tests revealed no significant differences between operative and conservative treatments. Compared to the normal right ATs, 60% of the average breaking strength was reached 3 months after surgery. Growth factor application did not result in significant improvements. Only a tendency towards higher blood vessel densities was noted in the groups treated with the factors. Collagen type I/III ratios also displayed no significant differences. This study indicates that there is no difference in the biomechanical outcome of conservative versus operative AT rupture treatment and only a marginal impact of short-term combinatory growth and angiogenesis factor application.