Biodegradable hybrid screws for ligament-bone interface regeneration

前交叉韧带受伤经常出现在新闻中，因为他们可能会结束足球运动员和运动员的职业生涯。其中一个著名的事件发生在2006年世界杯英格兰和瑞典之间的比赛中，迈克尔欧文撕裂了他的ACL。这不仅仅是精英运动员的问题。在英国，每年大约有20，000人需要ACL修复，而英国国民健康服务体系（NHS）每年进行大约11，000例ACL重建手术。ACL重建手术通常涉及从患者自身的腘绳肌腱中获取替代ACL移植物。通过关节镜（锁孔手术）移除受损的ACL，然后在膝关节区域的股骨（大腿骨）和胫骨（胫骨）中钻取隧道。通过隧道对齐/定位置换移植物，并通过界面螺钉将相对端固定在胫骨隧道中。我们的临床医生和我们的医疗器械合作伙伴Xiros已经确定了对新螺钉和ACL重建器械的未满足的临床需求。目前的金属螺钉最终会被身体排斥，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。目的是开发一种理想的螺钉，其具有生物活性，以刺激骨结合和结缔组织/骨界面的再生，并可生物降解地将移植物整合到骨中。螺钉还必须坚固、坚韧并具有一定的刚度。生物可降解聚合物/生物活性陶瓷复合材料螺钉存在，但它们经常失效并需要更换。这是因为生物活性成分埋在聚合物中，聚合物的降解速率不受控制，可能是灾难性的或导致囊肿。我们的混合螺钉将克服这些问题，提供强度和专门设计的生物降解速率，以匹配骨/结缔组织界面的恢复速率。在某些情况下，失败的不是螺钉，而是肌腱移植物，因此我们还将开发一种新的完全合成的器械，该器械无需从腘绳肌获取，并提供更可靠的长期性能，同时与宿主骨整合。

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.