改良全关节镜下胫骨Inlay技术重建后十字韧带的实验研究

目的 探讨采用改良全关节镜下胫骨Inlay技术重建膝关节后十字韧带(posterior cruciate ligament,PCL)手术方法的特点及优势.方法 设计专门的胫骨隧道形态及配套的胫骨钻头,设计移植物的形态和固定方法.在5具成人膝关节标本上模拟操作,年龄25～65岁;左膝2例,右膝3例.设计出全关节镜下胫骨Inlay技术重建PCL的手术操作流程(包括建立胫骨隧道的方法,移植物的引入等).操作完成后切开实验标本,进行二次观察,观察胫骨隧道内口的形态和位置是否达到设计的要求.通过对30张正常MRI片进行测量,确定胫骨隧道的角度,明确术中PCL定位器的角度.结果 胫骨隧道内口设计成14 mm×7 mm×15 mm的圆锥状,外口为直径7 mm的圆柱状,配套的胫骨钻头设计成分体式,钻头在体外装配.胫骨平台后缘斜坡与水平成36°～47°,定位器角度设定为50°.移植物使用异体跟腱,移植物骨块设计成圆锥状,与胫骨隧道内口相匹配,移植物胫骨隧道外口使用纽扣钢板固定.5例标本手术均获得成功,切开行二次检查结果显示,其中4例移植物和胫骨隧道匹配,另1例隧道外口直径偏小,移植物无法完全嵌入.结论 改良全关节镜下胫骨Inlay技术重建膝关节PCL手术具有操作简单、准确、快速、固定牢靠的特点.

Abstract：

Objective To improve the arthroscopic posterior cruciate ligament (PCL) reconstruction using tibial Inlay technique. Methods The special arthroscopic device and related fixation technique were designed. Five cadaveric knees were used to simulate the process of arthroscopic posterior cruciate ligament reconstruction using tibial Inlay technique. The knees were cut open to observe whether the outlet of the tibial tunnel shape and location met the design requirements. Thirty normal MRI films were measured to identify tunnel angle and localizer angle. Results The inner outlet of tunnel was conical shape(14 mm×7 mm×15 mm) and the outer outlet was cylinder-shaped (a diameter of 7 mm). The tibial drill was designed into a split structure and could be assembled in vitro. According to the data obtained from MRI films, the angle between the plane of posterior cruciate ligament and horizontal place was 36°-47°, and the localizer was fixed at 50°.The achilles tendon was used as implant and the allogft bones were designed into conical shape to fit the inner outlet of tunnel. The other end of implant to the proximal tibia was fixed with button plate. All reconstruction operations were performed under arthroscopy. The outcomes of procedure were satisfactory. There were no vascular or peripheral nerve injuries in the cadaveric knees The tunnel position was accurate and the shape of tunnel had met the design requirements. Conclusion Our results imply that improved arthroscopic of posterior cruciate ligament using tibial Inlay technique is simple, accurate, rapid and stable fixation.     

Histological comparison of fate of ligamentous insertion after reconstruction of anterior cruciate ligament: autograft vs allograft

Objective: To analyze the histological results and the biological remodeling of ligamentous insertion after the reconstruction of anterior cruciate ligament ( ACL) with autograft or allograft tendon. Methods: Extensor digitorum tendon was harvested from hind limb as graft material and transplanted to reconstruct the resected ACL in 12 mongrel dogs. Each free tendon end was secured by holding sutures and then the sutures were tied to the post screw at the femoral and tibial bony tunnel outlet after transplantation respectively. Autograft was randomly performed on one side of knee while allograft on the other side of knee. After transplantation, the histological analysis was undertaken at the 6th, 12th weeks and the 6th month using hematoxylin-eosin (HE) stain under light microscope. Results: The insertion structure of normal ACL typically consisted of four layers, i. e. , dense connective tissue, fibrocartilage, mineralized fibrocartilage and bone. There was a distinct regular tidemark line between fibrocartilage and mineralized fibrocartilage. At the 6th week postoperativcly, loose connective tissue presented in the interspace between graft and bony tunnel wall in both autograft and allograft groups. At the 12th week postoperatively, the collagenous fibers between autograft and tunnel wall became well organized and the four layers of insertion with discontinuous tidemark line were demonstrated indistinctly in autograft group but not in allograft group. At the 6th month postoperatively, both of a clear and continuous tidemark line and distinct four layers could be seen in autograft group. In allograft group, only a waved discontinuous tidemark line was shown and either the anatomic morphology or the maturity of insertion was inferior to that of autograft group. Conclusions: At the 6th month postoperatively, although the ligament-cartilage insertion is primarily formed after ACL reconstruction with autograft or allograft tendon, the histological morphology and the maturation of insertion of autograft tendon are better than those of allograft group, which suggests that postoperative rehabilitation should be paid more attention and could be safer if little delayed during ACL reconstruction with allograft tendon.     

Histological comparison of after reconstruction of fate of ligamentous insertion anterior cruciate ligament： autograft vs allograft

Objective ：To analyze the histological results and the biological remodeling of ligamentous insertion after the reconstruction of anterior cruciate ligament （ ACL ） with autograft or allograft tendon. Methods： Extensor digitorum tendon was harvested from hind limb as graft material and transplanted to reconstruct the resected ACL in 12 mongrel dogs. Each free tendon end was secured by holding sutures and then the sutures were tied to the post screw at the femoral and tibial bony tunnel outlet after transplantation respectively. Autograft was randomly performed on one side of knee while allograft on the other side of knee. After transplantation, the histological analysis was undertaken at the 6th, 12th weeks and the 6th month using hematoxylineosin （HE） stain under light microscope. Results： The insertion structure of normal ACL typically consisted of four layers, i. e. , dense connective tissue, fibrocartilage, mineralized fibrocartilage and bone. There was a distinct regular tidemark line between fibrocartilage and mineralized fibrocartilage. At the 6th week postoperatively, loose connective tissue presented in the interspace between graft and bony tunnel wall in both autograft and allograft groups. At the 12th week postoperatively, the collagenons fibers between autograft and tunnel wall became well organized and the four layers of insertion with discontinuous tidemark line were demonstrated indistinctly in autograft group but not in allograft group. At the 6th month postoperatively, both of a clear and continuous tidemark line and distinct four layers could be seen in autograft group. In allograft group, only a waved discontinuous tidemark line was shown and either the anatomic morphology or the maturity of insertion was inferior to that of autograft group. Conclusions： At the 6th month postoperatively, although the ligament-eartilage insertion is primarily formed after ACL reconstruction with autograft or allograft tendon, the histological morphology and the maturation of insertion of autograft tendon are better than those of allograft group, which suggests that postoperative rehabilitation should be paid more attention and could be safer if little delayed during ACL reconstruction with allograft tendon.     

Anterolateral rotatory instability in vivo correlates tunnel position after anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft

AIM To quantitatively assess rotatory and anterior-posterior instability in vivo after anterior cruciate ligament(ACL) reconstruction using bone-patellar tendon-bone(BTB) autografts, and to clarify the influence of tunnel positions on the knee stability.METHODS Single-bundle ACL reconstruction with BTB autograft was performed on 50 patients with a mean age of 28 years using the trans-tibial(TT)(n = 20) and trans-portal(TP)(n = 30) techniques. Femoral and tibial tunnel positions were identified from the high-resolution 3 D-CT bone models two weeks after surgery. Anterolateral rotatory translation was examined using a Slocum anterolateral rotatory instability test in open magnetic resonance imaging(MRI) 1.0-1.5 years after surgery, by measuring anterior tibial translation at the medial and lateral compartments on its sagittal images. Anterior-posterior stability was evaluated with a Kneelax3 arthrometer.RESULTS A total of 40 patients(80%) were finally followed up. Femoral tunnel positions were shallower(P 0.01) and higher(P 0.001), and tibial tunnel positions were more posterior(P 0.05) in the TT group compared with the TP group. Anterolateral rotatory translations in reconstructed knees were significantly correlated with the shallow femoral tunnel positions(R = 0.42, P 0.01), and the rotatory translations were greater in the TT group(3.2 ± 1.6 mm) than in the TP group(2.0 ± 1.8 mm)(P 0.05). Side-to-side differences of Kneelax3 arthrometer were 1.5 ± 1.3 mm in the TT, and 1.7 ± 1.6 mm in the TP group(N.S.). Lysholm scores, KOOS subscales and reinjury rate showed no difference between the two groups.CONCLUSION Anterolateral rotatory instability significantly correlated shallow femoral tunnel positions after ACL reconstruction using BTB autografts. Clinical outcomes, rotatory and anterior-posterior stability were overall satisfactory in both techniques, but the TT technique located femoral tunnels in shallower and higher positions, and tibial tunnels in more posterior positions than the TP technique, thus increased the anterolateral rotation. Anatomic ACL reconstruction with BTB autografts may restore knee function and stability.     

Anatomic assessment of femoral tunnel by transtibial drilling technique in double-bundle anterior cruciate liga- ment reconstruction： an in vivo study

Objective： To evaluate the anatomy of femoral tunnels created by simulated transtibial technique in double-bundle anterior cruciate ligament （ACL） reconstruction. Methods： Two tibial tunnels, anteromedial （AM） and posterolateral （PL）, were drilled 45° and 55° to tibial plateau respectively. On the femoral side, the AM and PL tunnels were drilled through anteriomedial portal. After the four tun- nels were established, the shaft of a reamer was introduced into the joint through tibial tunnel and reached against the lateral wall of intercondylar notch. The position that the reamer shaft can reach was marked and recorded. Results： Neither femoral AM nor PL tunnel opening can be fully or partially reached by the reamer shaft through the tibial AM tunnel in all cases. The evaluation through the tibial PL tunnel showed that only in 8 of 50 cases （16%） the femoral AM tunnel opening and in 4 cases （8%） the PL opening can be fully reached. On the other hand, in 12 cases （24%） the femoral AM tunnel opening and in 10 cases （20%） the PL opening can be partially reached by the shafts through the tibial PL tunnel. Conclusion： The result strongly suggests that transtibial technique is not well competent for femoral tun- nel drilling in anatomic double-bundle ACL reconstruction as we have hypothesized.     

Emergency iliosacral screw fixation assisted by TiRobot for unstable posterior pelvic ring fracture北大核心CSCD

Objective To evaluate the emergency iliosacral screw fixation assisted by TiRobot for unstable posterior pelvic ring fracture. Methods The 26 patients with unstable pelvic fracture were analyzed retrospectively who had undergone emergency iliosacral screw fixation at Department of Orthopedics & Traumatology, Beijing Jishuitan Hospital from June 2018 to December 2020. They were divided into 2 groups depending on whether orthopaedic TiRobot was used to assist screw insertion. In the observation group of 14 cases subjected to TiRobot-assisted insertion of iliosacral screws, there were 10 males and 4 females with an age of (45.9 ± 10.1) years; in the control group of 12 cases subjected to conventional manual insertion of iliosacral screws, there were 9 males and 3 females with an age of (49.2 ± 11.3) years. All the surgeries were conducted within 24 hours after injury. The 2 groups were compared in terms of screw insertion time, pin insertion, intraoperative blood loss, fluoroscopy time, postoperative screw position, fracture reduction and Harris hip score at the final follow-up. Results The 2 groups were comparable because there was no significant difference between them in their preoperative general clinical data or follow-up time (P>0.05). The screw insertion time [(16.1 ± 3.4) min] and fluoroscopy time [(8.1 ± 3.3) s] in the observation group were significantly shorter than those in the control group [(26.4 ± 5.4) min and (25.2 ± 7.4) s], and the pin insertions [1 (1, 2) times] and intraoperative blood loss [(10.5 ± 6.4) mL] in the former were significantly less than those in the latter [6 (3, 8) times and (24.8 ± 6.7) mL] (all P<0.05). Postoperatively, the sacroiliac screw position was excellent in 18 cases and good in 2 in the observation group while excellent in 14 cases, good in 2 and poor in 2 in the control group; the fracture reduction was excellent in 12 cases, good in one and fair in one in the observation group while excellent in 10 cases, good in one and fair in one in the control group, showing insignificant differences in the above comparisons (P>0.05). There was no significant difference either in the Harris hip score at the final follow-up between the 2 groups (P>0.05). Conclusion Compared with conventional manual insertion of iliosacral screws, emergency iliosacral screw fixation assisted by TiRobot can effectively decrease surgical time and reduce operative invasion due to a higher accuracy rate of screw insertion. © 2022 Chinese Journal of Orthopaedic Trauma. All rights reserved.     

经寰椎后弓上颈椎稳定性重建的解剖学研究

目的 通过解剖学测量,探讨经寰椎后弓螺钉固定重建上颈椎稳定性的解剖学基础.方法 测量39具干燥寰椎标本椎管内径宽度、螺钉进钉点后弓高度和宽度、寰椎椎动脉沟底后弓高度和宽度、经后弓螺钉固定钉道长度和侧块钉道长度、后弓固定与侧块固定进钉角度等解剖学数据.统计学分析所测量数据并对经寰椎后弓螺钉固定钉道长度与经侧块螺钉固定钉道长度两组数据配对student t检验,检验水准为α=0.05.结果 寰椎椎管内径宽度为(26.80±2.58)mm;进钉点寰椎后弓高度和宽度分别为(6.83±1.97)mm和(6.40±1.36)mm;椎动脉沟底后弓高度和宽度分别为(4.37±1.11)mm和(8.05±1.33)mm;经后弓螺钉固定钉道长度为(30.54±1.70)mm.进钉点置钉时钉道外倾角度为15°～20°、吻侧前倾角度为0°～5°.椎动脉沟底骨质高度小于颈椎常用螺钉直径3.5 mm的占25.6%(10具).经侧块螺钉固定钉道长度为(16.91±1.13)mm,进钉点置钉时钉道内倾角度为32.05°±6.03°、头侧前倾角度为5°.经后弓螺钉固定钉道长度与经侧块钉道长度两组数据配对student t检验统计分析结果显示差异有统计学意义(t=59.528,P＜0.001).结论 约有74.4%的人群可顺利经寰椎后弓螺钉固定完成上颈椎稳定性的重建,该技术不仅可使寰椎得到即刻、牢靠的稳定性,同时较寰椎经侧块螺钉固定技术具有较小的手术风险和操作难度,是一项具有推广价值的寰椎稳定技术.

Abstract：

Objective To investigate the anatomy of upper cervical vertebrae's stable reconstruction by poster arch of atlas screw by anatomic study. Methods To collect the anatomical data of 39 dry atlas with the average inner diameter of vessel of atlas, the average high and wide of the screw point of poster arch of atlas, the average high and wide of poster arch of atlas beneath the groove for vertebral artery, the tract length of poster arch screw, the tract length of lateral mass screw, the direction and angle of poster arch screw, and the direction and angle of lateral mass. Statistical comparison were performed with Student test between the tract length of poster arch screw and the tract length of lateral mass screw. Results The average inner diameter of vessel of atlas was (26.8±2.58) mm(21.7-31.0 mm). The screw point high and wide of poster arch of atlas were (6.83±1.97) mm and (6.40±1.36) mm respectively. The average high and wide of poster arch of atlas beneath the groove for vertebral artery were (4.37±1.11) mm and (8.05±1.33) mm respectively. The tract length of poster arch screw were (30.54±1.705) mm. The direction and angle of poster arch screw was 15°-20° incline laterally and 0°-5°incline cephalo. 25.6%(10 cases) patients with the diameter less than 3.5mm beneath the groove for vertebral artery. The direction and angle of lateral mass screw was 32.05°±6.03° incline medially and 5° incline cephalo. There were significant differences between the tract length of poster arch screw and the tract length of lateral mass screw(t=59.528, P＜0.001 ). Conclusion About 74.4% patients can reconstruct the upper cervical stable by poster arch of atlas screw. The technique can gain instant upper cervical stable, and reduce the risk of injury of blood vessel by over explore the atlas arch compare with the technique of lateral mass screw fixation of atlas. The technique is worth to promoting with its character of safe, easy perform and rigid fixation.     

关节镜下个体化前交叉韧带单束与双束解剖重建的近期疗效比较

Objective To compare clinical outcomes of double-bundle and single-bundle in individualized arthroscopic anatomical reconstruction of anterior cruciate ligament (ACL) . Methods The clinical data of 117 patients were reviewed who had received double-bundle or single-bundle arthroscopic ACL reconstruction from March 2007 through September 2009 in our hospital and had undergone complete follow-up. Of them, 35 cases had single-bundle ACL reconstruction and 82 double-bundle reconstruction. In the single-bundle group(group A), there were 31 men and 4 women, aged 28. 6 ±5. 1 years. In the double-bundle group(group B), there were 73 men and 9 women, aged 27. 6 ±5. 4 years. The 2 groups were comparable in the preoperative demographic data ( P > 0. 05). To evaluate the outcomes, Lachman and Pivot Shift exams , KT-2000, Lysholm and IKDC (International Knee Documentation Committee) scores, were adopted. Results The 117 patients received a mean follow-up of 15 months (from 11 to 25 months). The Lachman test showed 88. 6% (31/35) were normal in group A and 95. 1% (78/82) were normal in group B.The pivot-shift test showed 88. 6%(31/35) were normal in group A and 96. 3% (79/82) were normal in group B. Group A had a mean Lysholm score of 93. 4 ± 8. 2 and group B a mean Lysholm score of 93. 7 ±7. 0. There were no significant differences between the 2 groups in the above indexes ( P > 0. 05). By IKDC score, 71. 4% (25/135) were normal in group A and 93. 9% (77/82) were normal in group B. The KT-2000 test showed a mean of 1. 4 ± 0. 6 mm in group A and a mean of 1. 1 ± 0. 5 mm in group B. These 2 values were significantly different between the 2 groups ( P < 0. 05). Conclusions The individualized arthroscopic double-bundle anatomical reconstruction of ACL can maximally restore the anteroposterior and rotational stability. Arrangement of the ACL insertion site on the femoral and tibial side, three-portal technique and ruler application are keys for individualized anatomical double-bundle ACL reconstruction.     

Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system: an analysis of 38 cases

Objective： To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non-randomized case-control study. Methods： Atotal of 38 consecutive non-randomized patients with type A thoracolumbar fractures, which had been stabilized posteriorly from December 2006 to March 2009, were examined retrospectively more than 9 months after surgery. Twenty-one patients had been treated conventionally with open pedicle screw fixation （OPSF） and 17 patients received minimally invasive treatment with Sextant percutaneous pedicle screw fixation （SPPSF）. As a method of evaluation, the incision size, the intraoperation and post- operative volume of blood loss, operation time, postoperative hospital stay, blood transfusion, the radiological assessment of the sagittal Cobb＇s angle, vertebral body angle and vertebral body height were recorded and compared. Results： All patients were followed up for 8-24 months （average 11.6 months）. There were significant differences in the incision size, surgical blood loss, surgical draining Joss, operation time, hospital stay after operation, blood transfusion, the proportion of antalgic supplement and postoperative incisional VAS between the two groups （P〈0.05）. Mean preoperative kyphotic deformity was 16.0° and improved by 9.3° after surgery in OPSF group, but 15.2° and 10.3° respectively in SPPSF group. Mean preoperative angle of the fractured vertebral body was 15.9°and improved by 7.9° after surgery in OPSF group, but 14.9° and 6.6° respectively in SPPSF group. Mean anterior vertebral body height （% of normal） was 67.3% before surgery and 95.8% after surgery, but 69.1% and 90.1% respectively in SPPSF group. Mean posterior vertebral body height （% of normal） was 93.3% before surgery and 99.5% after surgery, but 88.9% and 93.3% respectively in SPPSF group. Among the patients whose 9-month follow-up films were available, 3.0° ofkyphosis correction was lost in OPSF group, but 3.2° in SPPSF group. And 1.0°of the angle of the fractured vertebral body correction was lost in OPSF group, but 1.5°in SPPSF group. Then 3.0% of the anterior vertebral body height correction was lost in OPSF group, but 2.2% in SPPSF group. And 3.0% of the posterior vertebral body height correction was lost in OPSF group, but 2.5% in SPPSF group. The sagittal Cobb＇s angle, vertebral body angle and anterior height of the fractured vertebra were all significantly different in each group before and after operation （P〈0.05）. There were no significant differences in the postoperative sagittal Cobb＇s angle, vertebral body angle and the improvement of the vertebral body height and the kyphotic deformity correction between OPSF and SPPSF groups （P〉0.05）, but there was significant difference in the postoperative anterior height of the fractured vertebra between the two groups （P〈0.05）. Conclusion： The percutaneous pedicle screw fixation through the pedicle of fractured vertebra using Sextant system is a good minimally-invasive surgical therapeutic choice for patients with type A thoracolumbar fracture except for that the SPPSF has a little insufficiency in resuming the anterior height of the fractured vertebra compared with OPSF.     

关节镜下个体化前交叉韧带单束与双束解剖重建的近期疗效比较

目的 探讨关节镜下个体化单束与双束解剖重建前交叉韧带(ACL)的技术,并比较二者的近期疗效.方法回顾性分析2007年3月到2009年9月行ACL个体化单、双束解剖重建且获得随访的117例ACL损伤患者资料,根据不同解剖重建方法分为两组:A组(个体化单束解剖重建)35例,男31例,女4例;平均年龄(28.6±5.1)岁.B组(个体化双束解剖重建)82例,男73例,女9例;平均年龄(27.6±5.4)岁.两组患者术前一般资料比较差异均无统计学意义(P>0.05),具有可比性.采用Lachman试验、轴移试验、KT-2000、国际膝关节评分委员会(IKDC)评分及Lysholm评分比较两组患者的疗效.结果 117例患者术后获11～25个月(平均15个月)随访.末次随访时Lachman试验结果:与健侧比较,A组完全正常者占88.6%(31/35),B组占95.1%(78/82);轴移试验结果:与健侧比较,A组完全正常者占88.6%(31/35),B组占96.3%(79/82);Lysholm评分:A组平均为(93.4±8.2)分,B组平均为(93.7±7.0)分,以上指标两组比较差异均无统计学意义(P>0.05).而KT-2000检测结果:A组平均为(1.4±0.6)mm,B组平均为(1.1±0.5)mm;A组IKDC评分正常者(A级)占71.4%(25/35),B组占93.9%(77/82),两组比较差异均有统计学意义(P<0.05).结论采用个体化解剖位双束重建能更好地恢复患者膝关节的稳定性.双束解剖重建术中ACL股骨与胫骨足迹、髁间窝宽度的判断对手术的设计至关重要,3入路技术、测量尺的应用是个体化ACL双束解剖重建的关键所在.

Abstract：

Objective To compare clinical outcomes of double-bundle and single-bundle in individualized arthroscopic anatomical reconstruction of anterior cruciate ligament (ACL) . Methods The clinical data of 117 patients were reviewed who had received double-bundle or single-bundle arthroscopic ACL reconstruction from March 2007 through September 2009 in our hospital and had undergone complete follow-up. Of them, 35 cases had single-bundle ACL reconstruction and 82 double-bundle reconstruction. In the single-bundle group(group A), there were 31 men and 4 women, aged 28. 6 ±5. 1 years. In the double-bundle group(group B), there were 73 men and 9 women, aged 27. 6 ±5. 4 years. The 2 groups were comparable in the preoperative demographic data ( P > 0. 05). To evaluate the outcomes, Lachman and Pivot Shift exams , KT-2000, Lysholm and IKDC (International Knee Documentation Committee) scores, were adopted. Results The 117 patients received a mean follow-up of 15 months (from 11 to 25 months). The Lachman test showed 88. 6% (31/35) were normal in group A and 95. 1% (78/82) were normal in group B.The pivot-shift test showed 88. 6%(31/35) were normal in group A and 96. 3% (79/82) were normal in group B. Group A had a mean Lysholm score of 93. 4 ± 8. 2 and group B a mean Lysholm score of 93. 7 ±7. 0. There were no significant differences between the 2 groups in the above indexes ( P > 0. 05). By IKDC score, 71. 4% (25/135) were normal in group A and 93. 9% (77/82) were normal in group B. The KT-2000 test showed a mean of 1. 4 ± 0. 6 mm in group A and a mean of 1. 1 ± 0. 5 mm in group B. These 2 values were significantly different between the 2 groups ( P < 0. 05). Conclusions The individualized arthroscopic double-bundle anatomical reconstruction of ACL can maximally restore the anteroposterior and rotational stability. Arrangement of the ACL insertion site on the femoral and tibial side, three-portal technique and ruler application are keys for individualized anatomical double-bundle ACL reconstruction.     

腘绳肌腱结嵌压固定法重建交叉韧带的临床应用与生物力学研究

目的探讨腘绳肌腱结嵌压固定法重建交叉韧带的可行性。方法对52例陈旧性前、后交叉韧带损伤患者在关节镜下行双股腘绳肌腱中间打结,嵌入瓶颈状股骨隧道内固定,胫骨端采用肌腱编织缝合在骨桥上打结固定,重建交叉韧带。其中前交叉韧带25例,前、后十字韧带同时重建15例,后交叉韧带12例。生物力学实验采用猪膝关节。股骨端固定分为肌腱结嵌入组(n=13)和骨髌腱骨(B PT B)介面螺钉固定组(B PT B介面钉组,n=11)。胫骨端固定分为肌腱编织缝合线在骨桥打结组(n=7)、肌腱编织缝合介面螺钉组(n=8)。进行最大拔出强度、最大位移和固定刚度等力学实验。结果术后随访49例,平均14 6个月,Lanchman试验阴性46例,阳性3例。术后Lysholm评分由术前56 7分提高到92 8分。按膝关节疗效评定标准,优46例,良3例。生物力学实验最大拔出强度肌腱结嵌入组高于B PT B介面钉组;固定刚度肌腱结嵌入组小于B PT B介面钉组;最大位移肌腱结嵌入组大于B PT B介面钉组。胫骨端固定抗拉强度和刚度骨桥打结组优于介面螺钉组。结论腘绳肌腱结嵌压固定重建交叉韧带生物力学抗拉强度能满足生理需求,方法可行;可克服位移因素,降低韧带松弛率,提高疗效。     

Isometry testing for anterior cruciate ligament reconstruction revisited

The purpose of this study was to determine the effect, if any, that varying the distal testing position (tibial level) has on isometry data produced with a common anatomic proximal testing position at the native anterior cruciate ligament (ACL) origin. During ACL reconstruction in 25 knees, in vivo isometry measurements were recorded using two different isometry testing methods, which differed in the tibial level of the distal fixation testing point. Method 1 tested distally at a point 13 cm peripheral to the native aCL insertion on a vector in line with the tibial tunnel. Method 2 tested distally at a point central in the native ACL insertion at the level of the intercondylar floor. All tibial tunnels were standardized with similar sagittal tunnel-plateau angles and similar tunnel lengths. The proximal testing point was standardized at a point that was anatomically located at or near the central ACL origin 7 mm anterior to “over the top” in all knees. Using these methods, length changes between the proximal and distal testing points were recorded in each knee with each testing method, with the knee ranged from 70° of flexion to full extension and from 70° to 140° of flexion. From these data, a total excursion from 0° to 140° of flexion was calculated. A nonanatomic distal testing point (Method 1) produced a 6 mm ± 1 mm total excursion, whereas anatomic testing points (Method 2) in the same knees produced a 1 mm ± 1 mm total excursion. From these data, the authors conclude that the tibial level of the distal isometry testing point has a significant effect on the resultant isometry measurement such that anatomic testing points are most isometric. Isometers that produce data between nonanatomic testing points should not be used to position tunnels for ACL reconstruction and should not be used to assume the elongation forces an ACL substitute will see when fixed at different points. Conversely, the clinical relevance of this study is that both anatomic graft position and anatomic graft fixation position are important and, when achieved, should result in minimal graft elongation with early postoperative range of motion, leading to a more stable long-term result.     

Kniegelenklaxizität beim vorderen Kreuzbandersatz

Background

The use of interference screws for femoral graft fixation in anterior cruciate ligament (ACL) reconstruction with hamstring grafts can result in rotation of the graft around the screw leading to changes in the final position of the graft within the bone tunnel.

Material and methods

In a prospective study 107 patients (54 right and 53 left knees) underwent ACL reconstruction with a hamstring tendon autograft. Femoral fixation of the graft was performed with a standard right-thread screw in all cases. Patients were assessed at 6 months postoperatively with the international knee documentation committee (IKDC) standard evaluation including instrumented laxity measurements and the results were compared between right and left knees.

Results

A significantly higher postoperative anterior laxity was observed in left knees with a negative Lachman test in only 64 % of the cases compared with 87 % in the group of right knees. Accordingly, instrumented laxity measurements of the reconstructed knee compared with the contralateral knee revealed significant differences between left and right knees (left knees 1.8±1.2 mm and right knees 1.0±1.4 mm)

Conclusions

This study demonstrates the importance of femoral graft positioning and its sensitivity to multiple influencing factors. The use of standard right-thread interference screws for femoral graft fixation in the mirrored situation of right and left knees may produce a systematic error in ACL reconstruction. Due to a possible rotation of the graft around the screw, the final position of the transplant may vary thus leading to significant changes in anterior translation of the operated knee.     

Initial fixation strength of a new hybrid technique for femoral ACL graft fixation: the bone wedge technique

Background Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. Hypothesis A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screw placed behind a bone wedge provides a higher fixation strength as aperture fixation with a screw alone matching the size of the tunnel. Study design Experimental laboratory study. Methods We evaluated the initial fixation strength (single cycle and cyclic loading tests) of hybrid and interference screw aperture fixation using different sized interference screws in porcine knees. Results Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. The use of an undersized screw alone resulted in low fixation strength. Conclusion The initial fixation strength of the hybrid technique with undersized screws is comparable to that of interference screw fixation matching the size. Clinical relevance The new “bone wedge fixation” is an alternative for ACL graft fixation without the risk of graft laceration and graft rotation.     

Mechanical evaluation of a ligament fixation system for ACL reconstruction at the tibia in a canine cadaver model

OBJECT: Excellent fixation of an artificial ligament in bone is mandatory for initial stability. ACL reconstruction with the LARS artificial ligament may fail if anchorage to bone is inadequate. The weak metaphyseal bone of the proximal tibia is prone to inadequate fixation. This study evaluates the initial mechanical stability of two techniques with an interference screw on the tibial side of an ACL reconstruction with the LARS ligament. METHODS: Six left tibias were obtained from 1 to 3 year old mongrel dog weighing 20 to 26 kg. ACL straight line reconstruction according to the technique described by J.P. Laboureau was performed with a 4.5 mm drill. Two tunnels were created in the tibia, one oblique and one transverse, the latter 2 cm below the former. Reconstruction was done with a 30-fiber LARS ligament and a 5.2 mm x 15 mm conical titanium cannulated interference screw. Group I had an interference screw in the oblique tunnel and group II had an interference screw in the transverse tunnel. Pull-out tests were performed parallel to the oblique tunnel on an Instron 8521 machine at a speed of 5 mm per minute until failure. The oblique tunnel was tested first then the transverse tunnel. RESULTS: Group I (n = 6): sliding value = 238 +/- 115 N. Group II (n = 6): sliding value = 998 +/- 148 N. This is statistically significant (p < 0.001, student t-test). CONCLUSION: One interference screw in a transverse tibial tunnel for ACL reconstruction with the LARS ligament is 4 times more resistant on loading and impact than an oblique screw.     

Pullout strength of tibial graft fixation in ACL-replacement with a patellar tendon graft: Interference screw versus staple fixation in human knees

Summary The endoscopic single incision technique for ACL reconstruction with a femoral half-tunnel may lead to a graft/tunnel mismatch and subsequent protrusion of the block from the tibial tunnel. The typical tibial fixation with an interference screw is not possible in these cases. Fixation with staples in a bony groove inferior to the tunnel outlet can be used as an alternative technique. Current literature does not provide biomechanical data of both fixation techniques in a human model. This study was performed to evaluate primary biomechanical parameters of this technique compared to a standard interference screw fixation of the block. 55 fresh-frozen human cadaver knee joints of a younger age (mean age: 44 years) were used. Grafts were harvested from the patellar tendon midportion with bone blocks of 25 mm length and 9 mm width. A 10 mm tibial tunnel was drilled from the anteromedial cortex to the center of the tibial insertion of the ACL. 3 different sizes of interference screws (7 × 30, 9 × 20 and 9 × 30 mm) were chosen as a standard control procedure (n = 40). For tibial bone-block fixation the graft was placed through the tunnel, the screw was then inserted on the cancellous or the cortical surface respectively. 15 knees were used for staple fixation. A groove was created inferior to the tunnel outlet with a chisel. The bone block was fixed in this groove with 2 barbed stainless steel staples. Tensile testing in both of the groups was carried out under axial load parallel to the tibial tunnel in a Zwick-testing-machine with a velocity of 1 mm/sec. Dislocation of the graft and stiffness were calculated at 175 N load. Maximum load to failure using interference screws varied between 506 and 758 N. Load to failure using staples was 588 N. Dislocation of the graft ranged between 3.6 and 4.7 mm for interference screw fixation and was 4.2 mm for staples. With both fixation techniques, the recorded failure loads were sufficient to withstand the graft loads which are to be expected during the rehabilitation period. Staple fixation of the bone block outside of the tunnel resulted in fixation strength comparable to interference screw fixation.      

Graft failure versus graft fixation in ACL reconstruction: histological and immunohistochemical studies in rabbits

The causes of graft failure after anterior cruciate ligament (ACL) reconstruction are multifactorial including the methods of graft fixation. The purpose of this study was to examine the ACL graft failure in three different methods of graft fixations including interference screw fixation, suture-post fixation and combined interference screw and suture-post fixation. We hypothesized that the fixation method after ACL reconstruction can affect the graft healing in tibial tunnel. Eighteen New Zealand white rabbits were categorized into three groups according to the method of fixation in unilateral ACL reconstruction with long digital extensor autograft. Histological examination demonstrated that the combined fixation and suture-post fixation groups showed significantly better integration between tendon and bone (P = 0.04). In immunohistochemical analysis, the combined fixation and suture-post fixation groups showed significantly higher BMP-2 and VEGF expressions than interference screw (P < 0.01). The tendon–bone healing after ACL reconstruction was affected by the method of graft fixation. Combined fixation with interference screw and suture-post reduced graft-tunnel micromotion and improved the graft healing in tibial tunnel.     

Femoral Tunnel Defect Filled With a Synthetic Dowel Graft for a Single-Staged Revision Anterior Cruciate Ligament Reconstruction

Bone defects are a common obstacle to successful revision anterior cruciate ligament (ACL) reconstruction. We describe the use of a synthetic bone graft plug to fill a cylindric defect after femoral interference screw removal. During revision ACL reconstruction performed through a 2-incision technique, we placed an outside-in guidewire for a new femoral tunnel that converged with the femoral screw from the primary ACL reconstruction. The screw was removed, and the resultant defect appeared very similar to the cylindric bone defect left after an osteochondral graft harvest. The confluence of the defect and the planned femoral tunnel would have allowed a “windshield wiper” effect of the graft at the lateral wall of the notch. We filled the screw defect with a synthetic bone graft plug to limit the aperture size of the femoral tunnel and to buttress the tendinous portion of the revision ACL graft, while maintaining proper anatomic graft position. In this article, we present a readily available all-arthroscopic option for repairing cylindric bone defects without the risk of an allograft or the morbidity of an autograft for a single-stage revision ACL reconstruction.     

The effect of soft-tissue graft fixation in anterior cruciate ligament reconstruction on graft-tunnel motion under anterior tibial loading

Purpose: To compare the motion of an anterior cruciate ligament (ACL) replacement graft within the femoral bone tunnel (graft-tunnel motion) when a soft-tissue graft is secured either by a titanium button and polyester tape (EndoButton fixation; Acufex, Smith & Nephew, Mansfield, MA) or by a biodegradable interference screw (Biointerference fixation; Endo-fix; Acufex, Smith & Nephew) An additional purpose was to evaluate the effect of the graft-tunnel motion on the kinematics of ACL-reconstructed knees and in situ force of the ACL replacement graft. Type of Study: Biomechanical experiment using an in vitro animal model. Methods: ACL reconstruction with a flexor tendon autograft was performed in 8 cadaveric knees of skeletally mature goats. The knee kinematics and the in situ force in the ACL replacement graft in response to anterior tibial loads were evaluated using the robotic/universal force-moment sensor testing system. The longitudinal and transverse graft-tunnel motion during anterior tibial loading was determined based on radiographic measurements parallel and perpendicular to the femoral bone tunnel, respectively. Results: In response to an anterior tibial load of 100 N, the longitudinal graft-tunnel motion for EndoButton fixation and Biointerference fixation was 0.8 ± 0.4 mm and 0.2 ± 0.1 mm, respectively (P < .05), whereas the transverse graft-tunnel motion was 0.5 ± 0.2 mm and 0.1 ± 0.1 mm, respectively (P < .05). Furthermore, the anterior tibial translation for EndoButton fixation (5.3 ± 1.2 mm) was also significantly larger than that for Biointerference fixation (4.2 ± 0.9 mm) (P < .05). With both fixations, however, no significant difference between the in situ forces in the ACL replacement graft and that in the intact ACL could be detected. Conclusions: EndoButton fixation of a soft-tissue graft via an elastic material resulted in significantly larger graft-tunnel motion, and consequently, greater anterior knee laxity compared with more rigid fixation using an interference screw closer to the intra-articular entrance of the bone tunnel. In terms of force distribution, the ACL replacement graft in both fixations still functioned as a primary restraint to an anterior tibial load close to the intact ACL.     

Tendon healing in a bone tunnel. Part I: Biomechanical results after biodegradable interference fit fixation in a model of anterior cruciate ligament reconstruction in sheep

Purpose: Interference fit fixation of soft-tissue grafts has recently raised strong interest because it allows for anatomic graft fixation that may increase knee stability and graft isometry. Although clinical data show promising results, no data exist on how tendon healing progresses using this fixation. The purpose of the present study was to investigate anterior cruciate ligament (ACL) reconstruction biomechanically using direct tendon-to-bone interference fit fixation with biodegradable interference screws in a sheep model. Type of Study: Animal study. Methods: Thirty-five mature sheep underwent ACL reconstruction with an autologous Achilles tendon split graft. Grafts were directly fixed with poly-(D,L-lactide) interference screws. Animals were euthanized after 6, 9, 12, 24, and 52 weeks and standard biomechanical evaluations were performed. Results: All grafts at time zero failed by pullout from the bone tunnel, whereas grafts at 6 and 9 weeks failed intraligamentously at the screw insertion site. At 24 and 52 weeks, grafts failed by osteocartilaginous avulsion. At 24 weeks, interference screws were macroscopically degraded. At 6 and 9 weeks tensile stress was only 6.8% and 9.6%, respectively, of the graft tissue at time zero. At 52 weeks, tensile stress of the reconstruction equaled 63.8% and 47.3% of the Achilles tendon graft at time zero and the native ACL, respectively. A complete restitution of anterior-posterior drawer displacement was found at 52 weeks compared with the time-zero reconstruction. Conclusions: It was found that over the whole healing period the graft fixation proved not to be the weak link of the reconstruction and that direct interference fit fixation withstands loads without motion restriction in the present animal model. The weak link during the early healing stage was the graft at its tunnel entrance site, leading to a critical decrease in mechanical properties. This finding indicates that interference fit fixation of a soft-tissue graft may additionally alter the mechanical properties of the graft in the early remodeling stage because of a possible tissue compromise at the screw insertion site. Although mechanical properties of the graft tissue had not returned to normal at 1 year compared with those at time zero, knee stability had returned to normal at that time. There was no graft pullout after 24 weeks, indicating that screw degradation does not compromise graft fixation.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 2 (February), 2002: pp 113–123