Animal experiment on repair of rotator cuff injury using cortical bone anchors

Objective To observe the healing of rotator cuff injury between the anchor and bone tunnel after repaired with allograft bone anchors in different periods of time. Methods Shoulder bone suture anchors were made using the cortical bone of adult sheep stored at-80℃.Six sheep were used as experimental animals.A median incision was made at the shoulder joint to isolate the supraspinatus tendon which was then sharply cut at its end.The end of supraspinatus tendon attached to the cortical bone was finished with a grater until the fresh bone surface was seen.Cortical bone anchors were slowly implanted into the prepared holes and supraspinatus tendon was sutured onto the fresh bone with sutures in anchors.Specimens were taken at weeks 4,8,and 12,respectively,after operation.Radiology,gross morphology and histology examinations were performed to observe the healing of supraspinatus muscle between the tendon and bone,and the histology turnover of bone anchors. Results The supraspinatus tendon was healed with fresh bones formed 12 weeks after operation.Radiology showed that the cortical bone anchors were fused with bones around them.HE staining of supraspinatus tendon tissue revealed that the cortical bone anchors were completely fused with bones around them 12 weeks after operation. Conclusion Rotator cuff injury between supraspinatus tendon and bone can be repaired with allograft cortical bone anchors,which are then fused with bones around them with no bone defect after operation.