组合式防旋转髓内针的研制及临床应用

TheCombinedAntirotationIntramedularyNailfortheTreatmentoftheDistalShaftoftheFemur:AnExperimentalStudyandClinicalApplication

股骨干远段骨折应用Ｋüｎｔｓｃｈｅｒ针常由于无法控制骨折远端旋转移位而造成治疗上的困难．内锁式髓针Ｉｎｔｅｒｌｏｃｋｉｎｇｎａｉｌ则由于其配套设备要求较高及手术难度等原因，使其推广受到限制．基于以上原因，我们研制了组合式防旋转髓内针（ｃｏｍｂｉｎｅｄａｎｔｉｒｏｔａｔｉｏｎｉｎｔｒａｍｅｄｕｌａｒｙｎａｉｌ，ＣＡＩＮ）．该针为分体式组合结构，通过内针的侧刃及远端分叉的两翼向外针传递扭矩，外针通过较高的刚度对断骨形成坚强约束．生物力学试验表明该针具备足够强度以对抗骨折部位的弯矩和扭矩，并由于运用侧刃传递扭矩，使扭矩均匀分布，克服了应力集中现象．自１９９２年１月～１９９３年５月应用治疗股骨干远段骨折４５例（４６侧），除１侧由于髓针植入过短失败外，其余４５侧平均随访３４．５个月，优良率达１００％．作者认为ＣＡＩＮ具有力学结构合理、手术方法简单、效果可靠及不需在透视下操作等优点，对于大多数股骨干远段骨折病例，为一值得推荐的方法．

Thetreatmentoffracturesoverthedistalhalfofthefemurisdifficultbecausetherota-tionbetweenthetwoendsofthefracturesegmentscannotbecontroledbyküntscher'snail.Inrecentyears,interlockingnailshavebeenavailableforthetreatment,howevertheiruseislimitedbecauseoftherequirementofthecostlyspecialinstrumentationandthedificultiesoftheinsertiontechniques.Thecombinedantirotationintramedularynail(CAIN)designedbytheauthorsforthepurposeconsistedoftwoparts,theinnernailandtheouternail.Thetwistingmomentumafectingthefracturedsegmentswasbornebythelateraledgesandthetwobranchedendsoftheinnernail,sothetwoendsofthefrac-turewereheldfirmlybythehardouternail.Thebiomechanicalexperimentswithhumanfemoralspeci-mensshowedthat,thestifnessofCAINwasenoughtoresistthebendingandtwistingmomentumatthesiteofthefracture;thetwistingmomentumwastransmitedbybothofthelateraledgsthustheconcentrationofthestresscouldbeavoided.FromJanuary1992toMay1993,45cases(46femurs)withfracturesoverthedistalhalfofthefemoralshaftweretreatedbyCAIN.Exceptonefailureduetoincorrectpositionofthenail.Altheother45femursobtaindexcelentresultswithanaverage34.5mouthsoffolow-up.TheauthorsconsideredthattheCAINisefectiveforthetreatmentofthedistalhalfofthefemoralshafts.