Summary
Bio-Bone-Locked Anchor providea new safe and effective choice for the repair of shoulder sport injury.
Abstract
Background
The incidence rate of tendon to bone interface injury in of sports medicine is high and difficult to repair itself. With the development of suture anchors, the repair of shoulder sport injury has changed from open surgery to minimally invasive arthroscopic operations. The pain of patients have greatly reduced and the early rehabilitation protocol becomepossible. After more than 20 years development, anchor material changed from the initial metal material to the diversification development: biodegradable materials, such as poly lactic acid, polyetheretherketone (PEEK) materials, and allogeneic cortical bone with biological healing potential. Different material anchor have different advantages and disadvantages, however, they all follow the principle of design: 1. Provided strong initial fixation strength to achieve tendon bone healing; 2. No interference with the tendon bone healing and normal tissue metabolism and lower anchor screw related complications.
Objective
To study initial fixation strength reliability and biological healing potential of new bio-bone anchors, by using biomechanical, radiological, histological methods in vitro and in vivo study.
Methods
1.Bone anchor manufacture: processed allograft cortical bone with digital precision machine, removed protein, surface decalcified, degreasing, antigen processing and disinfection. 2 In vitro study: (1) 6mm Bio-locked-bone anchors was pre-threaded with two UltraBraid suture in advance of each group, experimental group use "8" locked technique, the blank control group is not locked, and was knocked into 4.5mm, 5mm , 5mm, 6mm pre-drilled hole respectively. One end of suture is fixed on the sensor of biomechanical machine, the other end is free. And to test the reliability of “8” locked technique cyclic loading.(2)using fresh frozen human proximal humerus, the two lateral row knotless anchor ( anchor 6.0-mm Bio-bone-locked anchor anchor, 5.5-mm Footprint Ultra ) were inserted at interval of 10 mm in the greater tuberosity 15 mm laterally adjacent to the medial row position. To avoid bias caused by the bone density of insertion sites (anterior and posterior) of the greater tuberosity, the medial and lateral anchor were alternated equally inserted in a randomized manner, respectively;3. Animal experiment: bio-locked-bone anchor is knotted into the 5mm pre-drilled hole in the greater tuberosity of humerus of 2 or 3-month-old male goats. Humerus are harvested at 6 weeks, 12 weeks, 24 weeks and 48 weeks postoperatively, respectively. Specimens was evaluated by X-ray, CT, micro CT, biomechanical test and histological stain to dynamic observe outcomes.
Results
1. Locking mechanism of bio-bone locked anchor are effective and it can be individually used as the lateral row knotless anchor; 2. Bio-bone-lockedanchor has reliable biomechanical performance; 3. After knotted into the bone in vivo, early mechanical properties are reliable and stable, minimal bone composition changes, and host bone creeping substitution accomplished after 48 weeks.
Conclusion
New bio-bone anchor, (1) can provide reliable initial fixation strengthin 6 weeks before the tendon-bone interface healed; (2) can achieve complete bone creeping substitution after the tendon-bone interface healed, can preserve bone mass, leaving no foreign body. In all, Bio-Bone-Locked Anchor providea new safe and effective choice for the repair of shoulder sport injury.