摘要
目的 髌骨是人体内最大的籽骨，位于股四头肌腱内，是伸膝装置中有着重要功能的一个组件。髌骨骨折多见，约占1.6％。髌骨骨折属于关节内骨折，易造成关节面的不平整，带来膝关节的功能障碍和创伤性关节炎，往往需手术治疗。内固定的方法较多，AO张力带技术被认为是治疗髌骨骨折的经典方法，但是对于粉碎性骨折和冠状面的骨折不能取得满意的效果，其带来的并发症也是临床上常见的难题。
钛镍(TiNi)形状记忆合金因其材质的特殊性近年来被广泛地应用到临床，其中聚髌器（NT-PC）被大量地应用到髌骨骨折的治疗上，尤其在粉碎性骨折的治疗上取得了较好的效果。AO张力带与NT-PC逐渐成为临床上治疗髌骨骨折最常用的方法，本文从力学实验和临床观察两个方面入手，应用对比研究的方法，探讨二者的临床适用症、
方法 本研究分为两个部分，一是通过力学实验来比较NT-PC和AO张力带在髌骨横断骨折的固定上的差异。取新鲜成年尸体标本 8具，包括膝上40cm股骨及膝下19cm胫骨，保留股四头肌及关节囊，剔除其余软组织。双层塑料袋密封，冰柜保存备用。室温自然解冻，经肉眼观察及X线摄片排除骨质破坏及
退行性骨关节炎，于髌骨中点用板锯将髌骨锯开造成横断骨折模型。置于自制实验台，用特制夹具将股四头肌固定，能牵拉膝关节伸曲自如，标本分别应用NT-PC和改良AO张力带固定。胫骨端加压，高精度数显位移测量器固定于髌骨骨折线的两侧。记录胫骨端加压的力、髌骨骨折分离位移和膝关节屈曲角度。应用统计学软件包进行统计学分析。
二是通过对于我院自1998年8月1日 到2003年2月1日收治的78例应用NT-PC和改良AO张力带治疗髌骨骨折的患者的临床资料进行对比。其中男47例，女31例；年龄19～80岁(平均45岁)。髌骨横形骨折41例；斜型骨折17例，纵行骨折1例，粉碎性骨折13例，撕脱型骨折5例（均为下极撕脱），冠状面骨折1例。右侧髌骨骨折35例，左侧骨折43例。闭合性骨折69例，开放性骨折9例。骨折多由高能量损伤造成，其中交通事故36例，跪地伤24例，直接暴力打击9例，其他9例。合并颅脑损伤9例，股骨干骨折4例，锁骨骨折1例，多发骨折1例。骨折至手术时间≤8天，平均2.3天，无陈旧性骨折。行NT-PC治疗42例，AO金属张力带治疗36例。共获随访64例，14例失访，时间为6～14个月，平均10个月。
术后常规予以抗生素治疗。时间3～14天，平均6天。 除粉碎性骨折外，术后均不用配合外固定术，两种术式术后第二天
进行股四头肌舒缩练习，改良AO张力带1周左右进行屈膝和直腿抬高练习，2周后负重练习并下地行走。NT-PC治疗组第2天即下地。粉碎性骨折术后石膏固定10～14d，拆线后行膝关节功能锻炼。
结果 力学实验表明股四头肌收缩力和髌韧带的张力一起作用于髌股关节上，这种情况下膝关节屈曲度直接影响股四头肌力的大小，从而影响关节反作用力的大小。膝关节屈曲度愈大，股四头肌力也愈高，因而所合成的髌股关节反作用力也愈大。两种不同内固定方法，均能达到人体正常的生理载荷，以 AO克氏针内固定承载力较大，而 NT-PC承载力与之相接近相差8.7％，说明两者内固定均能满足要求，力学性能优越。
临床资料根据术后X线片和关节功能恢复情况参照陆裕甫等疗效评价标准评定疗效。AO张力带组1例发生感染，及时进行药敏试验并予以相应抗生素治疗，未影响骨愈合；1例术中见骨折碎块太小，固定失败，改用荷包缝合配合长腿石膏外固定；2例因针尾刺激皮肤，致使功能锻炼时间延搁。NT-PC组1例因髌骨上部粉碎严重，且股四头肌扩张部腱膜毁损严重，术后因NT-PC的持续加压作用致使髌骨爪上支嵌入骨质，但并未涉及关节面。
结论 本研究通过力学实验证明两种不同内固定方法，均能
达到人体正常的生理载荷，以 AO克氏针内固定承载力较大，而 NT-PC承载力与之相接近相差仅8.7％，说明两者内固定均能满足要求，力学性能优越。在髌骨骨折的治疗上， AO张力带与NT-PC并没有统计学上的差异，但是在粉碎性骨折的治疗上，前者要明显优于后者。NT-PC还兼有人为创伤小、操作简便、优良的生物相容性和低生物蜕变性等优点，并且可以不必二次手术取出，是治疗髌骨骨折的良好内植物，并应作为粉碎性髌骨骨折的首选内植物。
Objective Patella is the biggest sesamoid bone inside the human body, locating the inside of quadriceps tendon. It is an important module in the knee extension system. The fracture of patella is common, about 1.6% in human bone fracture. It belongs to the bone fracture inside the articulation, is easy to make the defect on the articular surface, bringing the dysfunction of the joint and trauma arthritis, usually need the surgical operation treatment. There are many methods of internal fixation. AO tension band technique is considered as the classic treatment to do with the fracture of patella including the transverse fracture, but can't achieve the satisfied effect with coronal fracture and the comminuted fracture; its complication is also a clinical common familiar problem to conquer.
Recent years TiNi shape memory alloy was applied widely in the clinic because of the special property, TiNi patellar concentrator (NT-PC) often use to treat patella fracture especially in comminuted fracture and get the good effect. AO tension band and the NT-PC become dominant gradually in treating patella fracture. This paper discusses their similarities and differences by the comparison of mechanics experiment and clinical observation.
Method This research is divided into two parts: one is the
mechanics experiment coming to compare the NT-PC to AO tension band in the fixation of the patellar transverse fracture. Eight fresh adult cadaver legs were involved, including about 40cm femur and 19cm tibias and reserving quadriceps and articular capsule. Double plastic bag seals completely, reserving by the ice cabinet, then defrost in the room temperature, being observed by naked eye and the X-ray expels the bone substance breakage and degenerative arthritis, subsequently sew the patella result in the transverse bone fracture model in the middle point of patella. It is placed in the self-made experimental device, using the specially made tongs to fix the quadriceps, keen joint flexing and extending normally and easily, the specimen was fixed by the NT- PC and AO tension band. The tibia adds to pressure, the high accuracy digital displacement machine affix in the two side of the patella fracture line. The force exerted on the tibia, the distance of fracture displacement and the degree of keen joint flexing was noted. All data was analyzed by the statistics software.
Another part is to compare the clinical information of patients who suffered patellar fracture , treated by AO tension band and NT-PC in our hospital from Aug. 1998 to Feb. 2003.all cases age from 19 to 80 years old(average 45 years old); 47 cases of male, 31 cases of female, involving 41 cases of transverse fracture of
patella,17 cases of oblique fracture,1 case of longitudinal fracture,13 cases of comminuted fracture,5 cases of sleeve fracture(all occurred in the inferior pole),1 case of coronal fracture.35 fractures occurred in right and 43 in left.69 cases was closed and 9 open. Much of fractures were made by the high-energy trauma, 36 cases by traffic accident, 24 cases during a fall onto the knee, 9 cases by a direct blow and 9 cases by other reasons. 9 cases combining brain trauma; 4 cases combining fracture of femur; 1 case combining fracture of collarbone; 1 case combining multiple fracture. The time of operation is within 8 days after trauma, average for 2.3 days. None was delay to treat.42 cases were treated by NT-PC and 36 by AO tension band. The time of follow-up varied from 6 to 14 months, average was 10 months,64 cases’ follow-up are available and 14 cases lost.
Antibiotic was applied after operation. The time varied from 3 to 14 days, average was 6 days. No external fixation was used except for comminuted fracture. The quadriceps contraction and relaxation practice were available in all the patients from the next day after the operation. Patients were applied AO tension band began to do exercise of knee joint flexion and extension and weight loading exercise after 2 weeks. Patients were treated by NT-PC do weight loading exercise fro
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