Tendon injuries remain challenging, secondary healing and prolonged immobilisation result in suboptimal outcome. Previous study by our group showed that demineralised bone matrix (DBM) can result in faster healing of a tendon enthesis. The aim of this study is to test different ways augmenting tendon with DBM to enhance tendon repair and regeneration. DBM strips were prepared from tibias of mature ewes. Patella, patellar tendon and tibias were dissected and the distal 1 cm of the patellar tendon was excised. 4 models were designed; Model-1, DBM strip was used to bridge the gap between the tendon and the tibial tuberosity. The DBM strip was stitched to the tendon using one bone anchor. Model-2, similar to model 1 with the use of 2 anchors. Model-3, similar to model 2, construct was off loaded by continuous thread looped twice through bony tunnels sited in the patella and in the tibial tuberosity. Model-4, similar to model 3 with 3 threads as off loading loop. All models were tested for pullout force and mode of failure.Introduction
Methods
Demineralised Bone Matrix (DBM) is widely used in Orthopaedics and dentistry as a bone graft substitute and may be used to augment bone formation in load bearing applications. In this study we examine the effect of gamma irradiation and freeze drying on the tensile strength of Demineralised Cortical Bone (DCB). Tibias were harvested from mature ewes and cut into bony strips. Demineralisation was done using 0.6M HCL and confirmed by X-ray. Specimens were washed until a pH of 7.0 +/_ 0.2 was achieved in the washing solutions. Specimens were allocated into 4 groups; group (A) non freeze dried non gamma irradiated, group (B) freeze dried non gamma irradiated, group (C) non freeze dried gamma irradiated mention the level of gamma irradiation and group (D) freeze dried and gamma irradiated. The maximum tensile force and stress were measured. Statistical analysis using the Mann-Whitney U test was carried out.Introduction
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