Biodegradable hybrid screws for ligament-bone interface regeneration

前十字韧带受伤经常出现在新闻中，因为这可能会结束足球运动员的职业生涯。其中一个广为人知的事件发生在2006年世界杯英格兰和瑞典的比赛中，迈克尔·欧文的前交叉韧带断裂。这不仅仅是精英运动员的问题。在英国，每年约有2万人需要修复前交叉韧带，英国国家医疗服务体系(NHS)每年进行约11,000例前交叉韧带重建手术。前交叉韧带重建手术通常需要从患者自己的腿筋肌腱中获取替换的前交叉韧带移植物。通过关节镜(锁孔手术)移除受损的前交叉韧带，然后在膝关节区域的股骨(股骨)和胫骨(胫骨)钻隧道。置换移植物通过隧道对准/定位，对端用干涉螺丝固定在胫骨隧道内。我们的临床医生和我们的医疗器械合作伙伴XIROS发现，对新的螺钉和前交叉韧带重建设备的临床需求尚未得到满足。目前的金属螺钉最终会被人体排斥，因为它们是生物惰性的，会经历纤维包裹，但它们也会撕裂移植物。这里的目的是开发一种理想的具有生物活性的螺钉，以刺激与骨的结合和结缔组织/骨界面的再生，并将移植到骨中的可生物降解的材料整合到骨中。螺丝还必须坚固、坚韧，并具有一定的硬度。可生物降解的聚合物/生物活性陶瓷复合材料螺丝是存在的，但它们经常会失效，需要更换。这是因为生物活性成分被埋在聚合物中，聚合物的降解速度不受控制，可能是灾难性的或导致包囊。我们的混合式螺钉将克服这些问题，提供强度和专门设计的生物降解率，以匹配骨/结缔组织界面的修复速度。在某些情况下，失败的不是螺丝钉，而是肌腱移植，因此我们还将开发一种新的完全合成的装置，它不需要从腿筋中取出，并提供更可靠的长期性能，同时与宿主骨结合。

Anterior Cruciate Ligament injuries are often in the news as they are potentially career ending for footballers and athletes. One of the well-known incidents was seen during 2006 World Cup match between England and Sweden, where Michael Owen ruptured his ACL. This is not just a problem for elite athletes. Approximately 20,000 people in the UK need ACL repair every year and the National Health Service (NHS) performs about 11,000 ACL reconstruction surgeries per year.Reconstructive surgery of the ACL usually involves harvesting replacement ACL graft from the patient's own hamstring tendons. The damaged ACL is removed through arthroscopy (keyhole surgery), then tunnels are drilled in femur (thigh bone) and tibia (shin bone) in the knee joint area. The replacement graft is aligned/positioned through the tunnels, and opposite ends are fixated in the tibial bone tunnel by interference screws. Our clinicians and our medical device partner Xiros have identified an unmet clinical need for new screws and ACL reconstruction devices. Current metallic screws will be eventually rejected by the body as they are bioinert and will undergo fibrous encapsulation, but they can also tear the graft. The aim here is to develop an ideal screw that would be bioactive, to stimulate bonding to bone and regeneration of the connective tissue/ bone interface and biodegradable integrating the graft into the bone. The screw must also be strong, tough and a certain stiffness. Biodegradable polymer/bioactive ceramic composite screws exist, but they often fail and need replacing. This is because the bioactive component is buried in the polymer and the degradation rate of the polymer is uncontrolled and can be catastrophic or cause cysts. Our hybrid screws will overcome those problems, giving strength and a specifically designed biodegradation rate to match the rate of restoration of the bone/connective tissue interface. In some cases, it is not the screw that fails, but the tendon graft, therefore we will also develop a new totally synthetic device that eliminates the need for harvesting from the hamstring and provides more reliable long term performance, while integrating with the host bone.