关节镜下解剖等长重建技术在重建前交叉韧带中的应用

[目的]探讨前交叉韧带(ACL)解剖等长重建技术在关节镜下应用的可行性及近期疗效.[方法]对20例前交叉韧带损伤行关节镜下ACL重建木.采用前交叉韧带解剖等长重建技术钻胫骨、股骨骨道.移植物用LARS人工韧带11例,用四股半腱肌股薄肌腱9例.LARS人工韧带用2枚界面螺钉固定韧带,四股半腱肌股薄肌腱股骨端用Endobutton固定、胫骨端用可吸收界面螺钉固定.[结果]手术时间LARS人工韧带组30～80 min,平均56 min.四股半腱肌股薄肌腱组80～120 min,平均100 min.20例均随访6～12个月,平均9个月.根据Lysholm膝关节功能评分,LARS人工韧带组术前评分22～65分(36.72±15.54)分;术后6个月评分80～98分(90.45±4.68)分(t=10.535,P＜0.01).四股半腱肌股薄肌腱组术前评分20～60分(37.11±12.26)分;术后6个月评分75～87分(80.44±4.16)分(t=9.615,P＜0.01).术后6个月LARS人工韧带组与四股半腱肌股薄肌腱组评分在统计学上有显著差异(t=10.569,P＜0.01).[结论]前交叉韧带解剖等长重建技术在关节镜下重建前交叉韧带术中操作简便,效果可靠,值得推广.LARS人工韧带组近期疗效明显优于四股半腱肌股薄肌腱组.     

保留交叉韧带前内侧束或后外侧束与残端重建ACL的价值

[目的]探讨保留交叉韧带(anterior erueiate ligament,ACL)部分束支与残端纤维对前交叉韧带(ACL)重建的价值.[方法]前交叉韧带损伤89例,其中运动伤32例,训练伤24例,交通事故伤23例,生活中扭伤10例.关节镜下发现ACL在股骨髁间窝处断裂24例,胫骨髁间止点断裂28例,ACL前内侧束(AMB)断裂14例,后外侧束(PLB)断裂23例.采用保留ACL残端四股胭绳肌腱结嵌压固定法重建32例,自体带髌骨块的股四头肌腱嵌压固定法重建20例;保留ACL前内侧束和后外侧束双股胭绳肌腱结嵌压固定重建37例.胫骨端采用界面钉固定和在胫骨桥上肌腱缝线打结固定.[结果]术后均得到随访,时间14～37个月,平均25个月,术后膝关节稳定性增强,Lysholm膝关节功能评分,术前平均67.5分,终末随访平均95.2分,术后提高27.7分.Rulermetr测试胫骨位移距离4 mm±3 mm 72例,6 mm±2 mm 17例;Lachman试验阴性79例,弱阳性8例,阳性2例.按膝关节疗效评定标准,优76例,良13例.[结论]保留交叉韧带前内侧束或后外侧束与残端重建ACL,有助于移植肌腱再血管化及爬行替代和本体感觉建立,有利于维持膝关节稳定性.     

经前交叉韧带腋下胫骨定位的后交叉韧带重建术

[目的]介绍关节镜下经前交叉韧带(anterior cruciate ligament, ACL)腋下胫骨定位的后交叉韧带(posterior cruciate ligament, PCL)重建术的技术及初步疗效。[方法] 2016年3月～2018年11月,对20例后交叉韧带断裂患者采用关节镜下经ACL腋下定位胫骨骨道,保残重建后交叉韧带。术中保留PCL残束,经前入路由内向外建立PCL股骨隧道,经ACL腋下置入胫骨隧道定位器,在后内入口观察下,于PCL止点平台下建立胫骨隧道。将移植腱由胫骨前侧经胫骨隧道拉入、再引入股骨隧道,股骨侧悬吊固定,拉紧移植物,胫骨侧挤压螺钉和"n"形钉固定。[结果]所有患者均顺利手术,无严重并发症。随访1年以上,Lysholm评分从术前(38.75±14.52)分显著增加至术后1年(93.70±4.23)分(P0.05)。影像测量后向应力胫骨后移由术前(10.81±3.07) mm减少至术后1年(3.86±1.10) mm (P0.05)。[结论]经ACL腋下定位胫骨骨道重建PCL,能精确的偏下偏外定位胫骨骨道;并可以最大程度的保留PCL残端,有利于重建术后韧带的愈合。     

保留残束重建前交叉韧带临床疗效分析

[目的]探讨保留前交叉韧带残束在重建前交叉韧带中的近期临床疗效及意义.[方法]2006年10月～ 2009年10月保留残束重建前交叉韧带39例,其中运动伤3例,交通事故伤24例,生活扭伤12例.男27例,女12例,年龄18 ～52岁,平均31岁.关节镜下发现前内侧束断裂13例,后外侧束断裂26例;在股骨髁间窝处ACL上止点断裂29例,在胫骨止点断裂10例.采用半腱肌、股薄肌肌腱重建单束前交叉韧带,均保留原前交叉韧带残束,胫骨端、股骨端采用可吸收挤压螺钉固定.[结果]本组39例患者术后均得到随访13 ～28个月,平均24个月,膝关节功能均得到明显改善,稳定性增强.Lysholm膝关节功能评分,术前平均70.5分,终末随访平均93.8分,术后提高23.3分.前抽屉试验阴性39例;Lachman试验阴性37例,弱阳性2例.按BRISTOL膝关节评分系统对术后疗效评分,优35例,良4例.[结论]对于前交叉韧带部分纤维束断裂患者行关节镜下保留残束的重建,能够促进移植韧带的再血管化及本体神经感受器的建立,有利于术后膝关节早期的康复训练.     

前交叉韧带重建术中胫骨骨道定位的应用解剖研究

[目的]探究前交叉韧带(anterior cruciate ligament,ACL)于胫骨止点处的解剖形态以及测量髁间窝顶线与胫骨平台交汇点至后交叉韧带前缘的距离对胫骨骨道定位的解剖学意义,为ACL重建术提供理论依据。[方法]选取新鲜成人膝关节标本8例,仔细剔除关节周围肌肉、后关节囊等结构,保留前后交叉韧带及两侧侧副韧带,保证膝关节正常屈伸范围。在屈伸膝关节时按照ACL纤维张力区将其分为前内束和后外束,在胫骨附着处将ACL切断制备ACL损伤模型。用测量工具和Phontoshop软件获取ACL基本解剖参数以及髁间窝顶线与胫骨平台的交汇点、ACL前缘、ACL胫骨止点的中心点分别至后交叉韧带前缘的距离。[结果]ACL平均体部直径为(11.21±0.76)mm,ACL在胫骨止点处的平均最大横径为(11.34±0.79)mm,平均最大前后径为(16.54±0.82)mm。前内束和后外束在胫骨止点处的平均面积分别为(113.35±29.65)mm~2和(83.29±16.99)mm~2。髁间窝顶线与胫骨平台的交汇点、ACL前缘以及ACL胫骨止点的中心点至后交叉韧带前缘的距离分别为(12.13±0.96)mm,(21.14±0.83)mm和(8.82±0.77)mm。[结论]利用胫骨平台骨道定位ACL在股骨的解剖止点现实可行,在ACL重建术中具有重要意义。     

前交叉韧带单束重建中两种股骨隧道制备方法的疗效比较

[目的]比较前交叉韧带单束重建中不同的股骨隧道制备方法对手术效果的影响.[方法]自2005年6月～2010年10月,采用自体半腱肌、股薄肌肌腱单束单隧道重建前交叉韧带140例,其中85例采用经胫骨隧道建立股骨隧道,55例采用经前内侧切口建立股骨隧道.通过Lysholm膝关节功能评分和屈膝30°位KT-1000前向松弛度对手术效果进行比较.[结果]所有患者术后均得到随访,随访时间至少12个月.术后Lysholm膝关节功能评分和KT-1000前向松弛度均较术前有改善.而术后经胫骨隧道组和经前内侧切口组在Lysholm膝关节功能评分和KT-1000前向松弛度方面比较无踢显差异.[结论]前交叉韧带单束重建术中经胫骨隧道建立股骨隧道与经前内侧切口建立股骨隧道两种方法可达到相同的治疗结果.     

双束重建前十字韧带骨道位置的临床研究

目的 研究双束重建前十字韧带患者术后骨道位置与临床效果的关系,初步探讨双束重建前十字韧带的定位评价.方法 随访研究2005年5至12月33例自体胭绳肌腱双束重建前十字韧带的患者,通过X线片测量其骨道位置.术后29例获14～22个月(平均18个月)随访,进行膝关节功能评分、KT-2000及Biodex肌力测试评价.结果 患者术后IKDC、Lysholm和Tegner评分及KT-2000结果均较术前显著改善(P＜0.01).前内束股骨骨道位于Blumensaat线水平的股骨外髁长度的29.68%±5.25%,高度的16.93%±5.73%.后外束股骨骨道位于Blumensaat线水平的股骨外髁长度的30.33%±9.44%,高度的31.24%±6.87%.前内束和后外束胫骨骨道分别位于胫骨平台长度的32.92%±5.37%和46.33%±7.74%.前内束股骨骨道前后位置与KT-2000 30°前后稳定性呈负相关(P＜0.05),即前内骨道越偏后30°稳定性越好.前内束股骨骨道相对外髁高低程度与患肢术后120°角速度下屈肌力矩呈正相关.后外束股骨骨道前后位置与60°角速度下屈肌力矩呈正相关,后外束胫骨骨道前后位置与120°角速度下屈肌力矩呈负相关.骨道位置与各功能评分均未表现出相关性.结论 双束重建前十字韧带可取得很好的临床效果.X线测量可以较客观、准确地反映骨道的定位情况并分析临床效果.     

后交叉韧带胫骨止点与双束重建胫骨骨道定位的临床解剖学研究

目的 解剖研究后交叉韧带(PCL)胫骨止点情况,确定PCL前外侧束(ALB)与后内侧束(PMB)胫骨止点的位置、形状与面积,探讨PCL双束四骨道重建中胫骨骨道定位标志与定位方法.方法 30例成人膝关节标本,根据屈伸膝关节过程中纤维束紧张与松弛情况,将PCL分为ALB与PMB,并确定各束中的功能束,用多种指标测量ALB、PMB与功能束的胫骨止点,解剖寻找双束四骨道重建PCL中胫骨骨道定位标志与定位方法.结果 PCL胫骨止点位于后髁间窝内,其纵轴由近内斜向远外,与胫骨干夹角平均为(16.5±1.4)°.ALB与PMB胫骨止点基本呈远近排列,ALB胫骨止点接近于菱形,平均面积为(90±20)mm2,PMB胫骨止点近似长方形,平均面积(96±32)mm2,二者无显著差异(P>0.05).ALB与PMB中均存在功能束,分别止于ALB胫骨止点的远外侧部及PMB胫骨止点的远内侧部,均接近椭圆形,面积分别为(35±12)mm2与(36±6)mm2,二者无显著差异(P>0.05).ALB功能束胫骨止点中心与PMB功能束胫骨止点中心距离为(12.7 ±1.9)mm.胫骨内、外侧髁间棘及胫骨上端后方骨嵴为重要的解剖标志.结论 PCL胫骨止点可以容纳两个胫骨骨道,PCL的ALB与PMB中均存在功能束,提示临床双束四骨道重建PCL时,胫骨骨道应分别定位于ALB与PMB功能束胫骨止点处.     

移植物不同固定方式对自体腘绳肌腱重建膝前交叉韧带术后股骨骨道影响的对比研究

[目的]探讨自体腘绳肌腱重建膝前交叉韧带,移植物不同固定方式对术后股骨隧道的影响,与临床疗效关系。[方法]88例前交叉韧带损伤病例行关节镜下自体半腱肌、股薄肌腱重建前交叉韧带,根据移植物股骨侧固定方式不同,分为三组。A组26例,采用Endobutton固定;B组22例,采用可吸收挤压螺钉固定;C组40例,采用Rigidfix固定。术后平均随访16.5个月,进行MRI检查,测量矢状位骨道开口、开口1 cm、骨道最宽处三点骨道直径,以术后1周对应部位骨道直径为衡量标准,对其差值进行统计学分析。采用Lysholm评分评估各组临床疗效。[结果]3组病例前交叉韧带术后骨道直径均有不同程度增宽。在股骨侧骨道最宽处、开口1 cm处,3组测量结果两两对比有统计学差异(P0.05),B组增宽明显,C组骨道增宽最小;在股骨骨道开口处,C组骨道增宽程度最小(P0.05),A、B组无对比差异(P0.05)。A、C组股骨骨道形态呈线形;B组股骨骨道形态呈锥形。所有病例关节稳定性良好,无1例出现不稳。术后Lysholm评分,A组(94.4±2.9)分,B组(93.4±3.6)分,C组(96.3±2.7)分,三组间比较无显著差异(P0.05)。[结论]移植物固定方式影响前交叉韧带术后骨道扩大,是骨道扩大发生的重要因素;固定方式、骨道扩大程度与术后临床疗效无相关性。     

关节镜下解剖等长重建技术在LARS韧带重建前交叉韧带中的应用

目的 探讨前交叉韧带(ACL)解剖等长重建技术在关节镜下LARS韧带重建前交叉韧带术中应用的可行性及近期疗效.方法 用LARS人工韧带对8例前交叉韧带损伤行关节镜下ACL重建术.采用前交叉韧带解剖等长重建技术钻胫骨、股骨骨道,将LARS韧带拉入骨道,韧带游离部分位于关节腔内,拉紧后2枚界面螺钉固定韧带.结果 手术时间30～80 min,平均56 min.术后无滑膜炎、韧带断裂、活动明显受限等并发症.8例均随访2～6个月,平均4个月.根据Lysholm膝关节功能评分,术前评分为22～65分(40.25±17.07)分;术后评分为80～93分(88.75±4.06)分(t=8.083,P＜0.01).结论 前交叉韧带解剖等长重建技术在关节镜下LARS韧带重建前交叉韧带术中操作简便,效果可靠,值得推广.     

镜下“8”字法缝线固定后交叉韧带胫骨撕脱骨折

[目的]介绍关节镜下“4”字位三入路“8”字缝线固定治疗后交叉韧带(posterior cruciate ligament,PCL)胫骨止点撕脱骨折的手术技术与初步效果。[方法]2019年3月-2021年3月,采用“4”字位三入路“8”字法缝线固定PCL胫骨撕脱性骨折28例。常规建立前外、前内和后内3个人口。从前内侧人口将2根强生Orthocord缝线经PCL前侧绕过后,从后内侧入口将缝线拉出并打结,防止骨块松脱。然后,将缝线两端交叉后,分别导入两个骨道,由胫骨前拉出。再次将PCL胫骨隧道定位器钩端置于骨块上,用其将骨块向后推压,进行临时复位固定。调整固定缝线使其从骨块后上方跨过,对膝施加前抽屉应力,复位固定骨块,同时拉紧缝线两端,使缝线牢固嵌压固定骨折块,将缝线尾端在骨道外口固定到门形钉或Versalok上完成固定。[结果]28例患者均顺利完成手术,无血管、神经损伤等严重并发症。Lysholm评分由术前(33.14±9.60)分显著增加至末次随访时(84.07±5.43)分(P<0.05);IKDC评分由术前(32.39±84.79)分显著增加至末次随访时(84.79±4.42)分(P<0.05)。末次随访时,临床检查显示,28例患者均无膝关节松弛或不稳定,膝活动度与健侧对称。影像方面,28例骨折均达临床骨愈合,无骨折移位。[结论]本技术具有简便易行、固定牢靠的优点,临床疗效满意。     

前交叉韧带胫骨平台止点的MRI测量及临床意义

目的应用MRI测量前交叉韧带（ACL）胫骨平台止点,为临床生理等长重建ACL提供参考。方法选择100例正常的膝关节磁共振检查结果,在适当的切面上绘制并测量胫骨平台前缘至后交叉韧带（PCL）前缘之间直线距离（AP）、在该径线上ACL胫骨侧止点中心至胫骨平台前缘之间距离（IA）、ACL胫骨止点中心至PCL前缘切线距离（DL）,并计算IA/AP的比值。结果IA为（19.5±2.8）mm,AP为（38.5±3.6）mm,IA/AP为（50.6±4.8）%,DL为（16.3±2.0）mm。结论MR I可用于测量ACL胫骨侧止点,重建ACL胫骨侧止点定位于胫骨平台中点稍后方可能更为合理。     

透明质酸预防关节镜下前交叉韧带重建术后膝关节粘连的临床研究

[目的]探讨透明质酸预防关节镜下前交叉韧带重建术后发生膝关节粘连的效果.[方法]选择2009年1月～2010年12月收治的60例行关节镜下前交叉韧带重建术的患者,随机选择30例术后关节腔内注射透明质酸2.5ml作为实验组;另30例常规手术不应用透明质酸作为对照组.随访观察术后6周时膝关节的伸屈活动度,Lysholm评分总改善率及VAS评分.[结果]60例均获随访,术后6周时膝关节活动度,实验组伸屈141.25.±9.98°,对照组伸屈133.75°±8.56.,具有统计学意义(P＜0.05);Lysholm评分总改善率,实验组84.8％,对照组65.4％,具有统计学意义(P＜0.05);VAS评分,实验组4.20±1.15,对照组6.10-1.59,具有统计学意义(P＜0.05).[结论]透明质酸能有效预防前交叉韧带重建术后膝关节粘连的发生.     

前内侧入路解剖重建单束前交叉韧带的临床评估

目的评估关节镜下经前内侧入路解剖重建单束前交叉韧带(ACL)的位置、形态及临床效果。方法对25例ACL断裂患者在关节镜下经前内侧入路应用解剖重建技术行单束ACL重建术,移植物应用自体腘绳肌腱。术后行X线、MRI检查,了解骨道情况,观察移植物形态及张力,并与11例健侧膝关节的正常ACL进行对比。应用Lysholm评分系统评估膝关节功能。结果术后X线片显示股骨隧道内口位于髁间窝顶与股骨后缘皮质线交叉点前缘,胫骨隧道内口位于髁间窝顶后方。MRI显示所有重建ACL张力良好,ACL上倾角为50.82°±4.57°,胫骨平台止点至前缘距离与平台纵径比值为0.50±0.04,两项与对照组比较差异均无统计学意义(P0.05)。患者均获得随访,时间为13~44个月。Lysholm评分术后为92.20分±4.29分,明显高于术前的64.76分±7.16分(P0.01)。结论关节镜下经前内侧入路解剖重建ACL的位置及形态接近解剖结构,早中期临床效果满意。     

The effect of section of the medial collateral ligament on force generated in the anterior cruciate ligament

Ten fresh-frozen knees from cadavera were instrumented with a specially designed transducer that measures the force that the anterior cruciate ligament exerts on its tibial attachment. Specimens were subjected to tibial torque, anterior tibial force, and varus-valgus bending moment at selected angles of flexion of the knee ranging from 0 to 45 degrees. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by applied varus moment. When valgus moment was applied to the knee, force increased dramatically after section of the medial collateral ligament; the increases were greatest at 45 degrees of flexion. Section of the medial collateral ligament had variable effects on the force generated in the anterior cruciate ligament during internal rotation but dramatically increased that generated during external rotation; these increases were greatest at 45 degrees. Section of the medial collateral ligament increased mean total torsional laxity by 13 degrees (at 0 degrees of flexion) to 20 degrees (at 45 degrees of flexion). Application of an anteriorly directed force to the tibia of an intact knee increased the force generated in the anterior cruciate ligament; this increase was maximum near the mid-part of the range of tibial rotation and minimum with external rotation of the tibia. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by straight anterior tibial pull near the mid-part of the range of tibial rotation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Knee stability following anterior cruciate ligament rupture and surgery. The contribution of irreducible tibial subluxation

BACKGROUND: Knee stability after anterior cruciate ligament reconstruction is generally determined by measuring total anteroposterior tibial motion. In spite of a decrease in excessive anteroposterior tibial motion after anterior cruciate ligament reconstruction, problems can still develop. In the present study, we sought to define the tibiofemoral relationship more accurately with use of stress radiographs of human knees after anterior cruciate ligament rupture and after anterior cruciate ligament reconstruction. METHODS: A previously described radiographic technique was used to evaluate the position of the tibia relative to the femur with the application of an anteriorly directed tibial force and subsequently with the application of a posteriorly directed tibial force. Tibial position and total tibial translation were calculated from these radiographs. In addition, KT-1000 measurements were obtained. Three groups of patients were studied: Group 1 included twenty-eight patients with an untreated anterior cruciate ligament rupture, Group 2 included nineteen patients who had undergone a clinically successful anterior cruciate ligament reconstruction, and Group 3 included twenty-five control subjects with normal knees. RESULTS: KT-1000 testing showed that the average side-to-side differences in Group 1 (5.8 mm) and Group 2 (2.7 mm) were significantly different from that in Group 3 (0.8 mm) (p < 0.01 and p < 0.05, respectively). Stress radiographs showed that the average total tibial translation in Group 1 (9.8 mm) was significantly different from those in Group 2 (5.6 mm) and Group 3 (4.3 mm) (p < 0.05 and p < 0.001, respectively). Within Group 1, knees with radiographic signs of osteoarthritis were more stable, with an average total tibial excursion of 6.8 mm. The improved stability of the reconstructed knees in Group 2 and the osteoarthritic knees in Group 1 was not entirely the result of decreased anterior tibial translation; it was, in part, due to an irreducible anterior subluxation of the tibia. A posteriorly directed stress in these knees did not reduce the tibia to the anatomic position relative to the femur; the osteoarthritic knees in Group 1 were 9.9 mm short of full reduction and the knees in Group 2 were 3.1 mm short of full reduction (p < 0.01) CONCLUSIONS: Irreducible tibial subluxation can be present in the knee following surgical reconstruction of the anterior cruciate ligament. Osteoarthritic changes following an untreated anterior cruciate ligament rupture are also associated with uncorrectable tibial subluxation along with a decrease in instability. The irreducible tibial subluxation could explain why osteoarthritic changes still may develop in stable, reconstructed knees in spite of the improved stability. Currently used arthrometric measurements, such as KT-1000 scores, do not measure this phenomenon.     

Anterior cruciate ligament deficiency alters the in vivo motion of the tibiofemoral cartilage contact points in both the anteroposterior and mediolateral directions

BACKGROUND: Quantifying the effects of anterior cruciate ligament deficiency on joint biomechanics is critical in order to better understand the mechanisms of joint degeneration in anterior cruciate ligament-deficient knees and to improve the surgical treatment of anterior cruciate ligament injuries. We investigated the changes in position of the in vivo tibiofemoral articular cartilage contact points in anterior cruciate ligament-deficient and intact contralateral knees with use of a newly developed dual orthogonal fluoroscopic and magnetic resonance imaging technique. METHODS: Nine patients with an anterior cruciate ligament rupture in one knee and a normal contralateral knee were recruited. Magnetic resonance images were acquired for both the intact and anterior cruciate ligament-deficient knees to construct computer knee models of the surfaces of the bone and cartilage. Each patient performed a single-leg weight-bearing lunge as images were recorded with use of a dual fluoroscopic system at full extension and at 15 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion. The in vivo knee position at each flexion angle was then reproduced with use of the knee models and fluoroscopic images. The contact points were defined as the centroids of the areas of intersection of the tibial and femoral articular cartilage surfaces. RESULTS: The contact points moved not only in the anteroposterior direction but also in the mediolateral direction in both the anterior cruciate ligament-deficient and intact knees. In the anteroposterior direction, the contact points in the medial compartment of the tibia were more posterior in the anterior cruciate ligament-deficient knees than in the intact knees at full extension and 15 degrees of flexion (p < 0.05). No significant differences were observed with regard to the anteroposterior motion of the contact points in the lateral compartment of the tibia. In the mediolateral direction, there was a significant lateral shift of the contact points in the medial compartment of the tibia toward the medial tibial spine between full extension and 60 degrees of flexion (p < 0.05). The contact points in the lateral compartment of the tibia shifted laterally, away from the lateral tibial spine, at 15 degrees and 30 degrees of flexion (p < 0.05). CONCLUSIONS: In the presence of anterior cruciate ligament injury, the contact points shift both posteriorly and laterally on the surface of the tibial plateau. In the medial compartment, the contact points shift toward the medial tibial spine, a region where degeneration is observed in patients with chronic anterior cruciate ligament injuries.     

Tibial rotation in anterior cruciate deficient knees: an in vitro study

The role of the anterior cruciate ligament in controlling tibial rotation was evaluated in four cadavera knee joints. Tibial rotation and anterior drawer tests were performed at multiple angles of knee flexion both before and after arthroscopic surgical section of the anterior cruciate ligament. Measurements were made using an instrumented electrogoniometer and force transducer system (GenucomTM). The results suggest that under clinically applied loads, rotation of the tibia is not constrained by the anterior cruciate ligament. The results also indicate an interpretation for anterior drawer tests when accompanied by an imposed tibial rotation. J Orthop Sports Phys Ther 1989;11(4):146-149.     

Measurement of stability of the knee and ligament force after implantation of a synthetic anterior cruciate ligament. In vitro measurement

A Gore-Tex prosthetic ligament was inserted, with an over-the-top femoral placement, into thirteen fresh-frozen cadaver knees as a substitute for the anterior cruciate ligament. The femoral eyelet was screwed into bone and the tibial eyelet was attached to a force-transducer, which was positioned and locked on a tibial slider track to record forces in the ligament as the tibia was externally loaded. A reference position was established for the tibial eyelet so that, after the Gore-Tex ligament was implanted, the total anterior-posterior laxity of the knee (at 200 newtons of applied tibial force) matched that of the intact knee (that is, before the anterior cruciate ligament had been cut) at 20 degrees of flexion. With both ends of the ligament secured in the knee, repeated 200-newton anterior-posterior load cycles produced an increase of five to seven millimeters in the total laxity. This apparent stretch-out of the ligament could be worked out of the knee by manually flexing and extending the knee thirty times between zero and 90 degrees of flexion while a constant 200-newton force was applied to the tibial eyelet. After implantation of the Gore-Tex ligament, the laxity of the knee matched that of the intact specimen at 20 degrees of flexion and matched it within one millimeter at zero, 5, and 10 degrees of flexion. For each millimeter that the tibial eyelet was moved distally, the total anterior-posterior laxity decreased by the same amount. The anterior stiffness of the knee after implantation of the Gore-Tex ligament was always less than that of the intact specimen. With an applied extension moment of ten newton-meters, section of the anterior cruciate ligament increased hyperextension of the knee by 2.3 degrees; implantation of the Gore-Tex ligament did not restore full extension, even when the ligament was over-tightened by using a distal location for the tibial eyelet. When the eyelet was in the reference position, the ligament forces ranged from three to 319 newtons when the knee was in full extension, they rose dramatically as the knee was hyperextended, and they decreased to zero in most specimens as the knee was flexed more than 15 degrees. The pull of the quadriceps tendon against fixed resistance always increased the ligament forces. The application of tibiofemoral contact force reduced the ligament forces that were generated during a straight anterior tibial pull.(ABSTRACT TRUNCATED AT 400 WORDS)