Bone plug versus suture fixation of the posterior horn in medial meniscalallograft transplantation: a biomechanical study

This study was performed to determine if a meniscal al- lograft with attached bone plug and suture offers superior ixation when compared to allograft afixed with suture alone through a bony tunnel. Seven pairs of human cadaver proximal tibia specimens were obtained. The specimens were then randomly assigned to either Group 1 (suture alone) or Group 2 (bone plug plus suture). All Group 1 specimens had the meniscus detached at the bony insertion of the anterior and posterior horns, with two No. 2 Ethibond sutures placed at the posterior root insertion. All Group 2 specimens had a posterior horn with a bone plug and two No. 2 Ethibond sutures. Both groups had their respective sutures passed through a 7 mm tibial tunnel and secured over a screw and post on the proximal tibia. The specimens were then loaded to failure. The mean failure load for Group 1 was 111.8 N (SD: 21 N) and for Group 2 was 112 N (SD: 32 N). Based on the Wilcoxon Rank-Sum analysis, the two groups were not signiicantly different. This study demonstrated no difference in the mean pullout strength of medial meniscal allograft posterior horn ixation between the two groups. This biome- chanical cadaveric study demonstrated that it may not be necessary to use an attached bone plug for medial meniscal transplant ixation, as using suture alone will sufice. The choice of using suture alone for the posterior horn meniscal attachment eases the technique of surgery when compared to using a bone plug plus suture.     

关节镜下Ethibond缝线复位固定治疗后交叉韧带胫骨止点撕脱骨折的临床疗效

目的探讨关节镜下Ethibond缝线复位固定治疗后交叉韧带(posterior cruciate ligament,PCL)胫骨止点撕脱骨折的临床效果。方法对2015年2月至2017年12月我院收治的22例PCL胫骨止点撕脱骨折病人,在关节镜下常规前内、前外侧入路结合双后内侧入路显露骨折,将PCL重建定位器置入并在其引导下由前内向后于撕脱骨折床3点和9点处钻出导针,制造两骨隧道。术中使用双根5号Ethibond缝线在韧带后方骨块近侧打结,经胫骨双骨隧道将缝线拉出于胫骨前侧,充分复位骨折块,缝线收紧打结固定。术后定期随访,了解骨折复位、愈合情况及活动度,采用KT 1000测量及后抽屉试验评估膝关节稳定性,比较手术前后的Lysholm评分、Tegner评分、国际膝关节评分委员会(International Knee Documentation Committee,IKDC)评分。结果随访时间为19~28个月,平均24.5个月。术后6周骨折均愈合,复位良好。术后6个月,所有病人后抽屉试验均为阴性,无伸膝、屈膝受限,平均屈膝活动度为138.5°±3.5°。手术前后的KT 1000测量值分别为(10.9±0.7)mm、(1.5±0.6)mm,Lysholm评分分别为(36.5±4.9)分、(94.2±3.3)分,Tegner评分分别为(2.6±0.8)分、(6.7±0.4)分;IKDC评分:术前C级7例(31.82%)、D级15例(68.18%),术后A级21例(95.45%)、B级1例(4.55%)。上述指标手术前后的数值比较,差异均有统计学意义(P均<0.05)。结论关节镜下经胫骨双骨隧道应用5号Ethibond缝线复位固定治疗PCL胫骨止点撕脱骨折,固定方法简便可靠,临床疗效满意。     

A case of excision of peri-articular cyst and reattachment of meniscotibial ligament with suture anchor

The authors report a case of peri-articular cyst around the knee joint owing to insufficient meniscotibial ligament. After excision, the defective peripheries of the meniscus and capsule were securely re-attached to the margin of the tibial plateau using suture anchors. A 37-year-old man presented with right knee pain. Magnetic resonance imaging revealed a detached meniscotibial ligament (coronary ligament) on the anteromedial side of the knee joint and an elevated deep medial collateral ligament with cystic fluid collection. The cyst was excised by meticulous dissection to expose the free peripheral edge of the meniscus and the margin of the tibial plateau. Two suture anchors were placed immediately beneath the joint line under the subchondral bone. The attachment of the meniscus to the tibial plateau was rendered secure by arthroscopy. At 9 months postoperatively, the patients had no complaints related to the involved knee.     

Arthroscopic reduction of posterior cruciate ligament tibial avulsion fracture using two cross-linked pull-out sutures: A surgical technique and case series

Surgical treatment of the posterior cruciate ligament (PCL) tibial avulsion fracture is challenging due to the deep-seated location of the lesion with complex adjacent anatomy and usually with small-sized bone fragment. We introduce a novel arthroscopic reduction technique using two cross-linked pull-out sutures (2XLPOS) through triple bone tunnels in posterior cruciate ligament (PCL) tibial avulsion fracture.Posterior trans-septal portal was established following the four standard arthroscopic portals. Bilateral margins of the PCL with 1～2?mm margin from the border were penetrated using suture hook. Fiberwire sling tied with a No. 0 PDS knot was introduced anterior to the PCL by the two posteriorly pulled shuttle sutures. Three bone tunnels were drilled in the inferomedial, inferolateral, and apex edge of the avulsed tibial crater. Each end of the Fiberwire was drawn out through the inferomedial and inferolateral bone tunnel, respectively. Two ends of the No. 0 PDS were drawn out through the apex tunnel by the same manner. Fiberwire was tied on the anteromedial aspect of the proximal tibia with one strand of the No. 0 PDS placed underneath the Fiberwire knot. And, the No. 0 PDS loop was tied to complete cross-linking of pull-out construct.Arthroscopic reduction of PCL tibial insertion avulsion fracture using 2XLPOS technique was performed in eleven patients. Mean range of motion at the first postoperative year was 126.8°. Mean Lysholm score, Tegner activity scale, and IKDC was 69.2, 4.2, and 58.1, respectively. Posterior instability decreased from mean 12.6?mm preoperatively to 3.2?mm at 1-year postoperative follow up. Radiographic union of the fracture site was confirmed in 11 cases. Our new surgical technique yielded good clinical and radiological outcome, and we consider it is unique in utilizing two cross-linked sling type pull-out suture constructs and triple bone tunnels for their passage.     

Arthroscopic suture fixation for bony avulsion of the posterior cruciate ligament

We describe a new arthroscopic technique for suture fixation of a posterior cruciate ligament (PCL) avulsion fracture from the tibia. This technique is indicated when the size of the avulsed fragment is small and fixation with a screw or pins is inadequate. Three portals are used: a parapatellar anteromedial portal, a high posteromedial portal, and a posterolateral portal. Using a PCL tibial guide, 2 bone tunnels are made from the anterior cortex of the tibia to the medial and lateral border of the avulsed site. One or 2 strands of 23-gauge wire or multiple nonabsorbable sutures are used for fixation through the tunnels. If the bony fragment is small or comminuted, fixation with wires or sutures leads to rigid fixation and early rehabilitation.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 7 (September), 2001: pp 776–780     

膝关节半月板根部附着区的解剖学测量

目的:测量国人膝关节内外侧半月板前后根部附着区的解剖学数据,为临床修复半月板根部损伤提供解剖学基础。方法:选取30个国人成人尸体膝关节标本,其中男16例,女14例;死亡年龄35～68(55.6±7.8)岁。对半月板根部附着区结构进行解剖,测量内外侧半月板根部附着区中心点与胫骨内外侧髁间棘、后交叉韧带前缘、内侧胫骨平台软骨后方外侧缘及外侧胫骨平台软骨后方内侧缘等标志点的位置关系和各个附着区的面积。结果:内侧半月板后根部附着区:中心点位于胫骨内侧髁间棘后方(11.73±3.10) mm、外侧(2.77±0.86) mm,后交叉韧带前缘前(2.76±0.76) mm,内侧平台软骨外侧缘外(3.92±0.22) mm,附着区面积(31.29±5.18) mm~2。内侧半月板前根部附着区:中心点位于胫骨内侧髁间棘前方(25.40±5.27) mm、外侧(3.01±0.86) mm,附着区面积(46.18±11.60) mm~2。外侧半月板后根部附着区:中心点位于胫骨外侧髁间棘后方(4.51±1.35)mm、内侧(1.85±0.34) mm,后交叉韧带前缘前(6.91±1.11) mm,外侧平台软骨内侧缘内(3.16±0.96) mm,附着区面积(44.10±6.23) mm~2。外侧半月板前根部附着区:中心点位于胫骨外侧髁间棘前方(12.97±2.92) mm、外侧(1.31±0.22) mm,附着区面积(60.84±14.98) mm~2。结论 :该试验定量描述内外侧半月板前后根部附着区的面积以及其中心点与相应标志点的位置关系,为临床修复半月板根部损伤提供一定的解剖学参考。     

New Meniscus Repair Technique for Peripheral Tears Near the Posterior Tibial Attachment of the Posterior Horn of the Medial Meniscus

We introduce a suture technique to repair a peripheral tear near the posterior tibial attachment of the posterior horn. A suture hook was inserted through the posteromedial portal, and the peripheral capsular rim was penetrated from superior to inferior by the sharp hook. Both relay limbs were brought out through the posteromedial portal. The outer limb of the superior peripheral capsular rim was identified with a hemostat. An 18-gauge spinal needle loaded with a No. 0 polydioxanone suture (PDS) was introduced into the joint from the anteromedial portal; it was passed through the joint space until it penetrated the inner torn meniscus. The PDS suture loaded within the needle was pushed into the joint and picked up through the posteromedial portal. The needle was pulled out of the torn meniscus and readvanced over it while the suture was kept loaded. The other limb of the suture from the tip of the spinal needle was retrieved through the posteromedial portal. The initial PDS suture limb was hooked to the shuttle-relay system; it then was passed through the inner torn meniscus and the peripheral capsular rim. The suture limb exiting from the peripheral capsular rim was used as a post and was joined to the other suture limb to form a sliding knot.     

Reducing the “killer turn” in posterior cruciate ligament reconstruction

Purpose: Graft abrasion caused by sharp graft angulation at the graft-tunnel margin of the proximal tibia (the “killer turn”) may cause graft failure after posterior cruciate ligament (PCL) reconstruction using the traditional anteromedial route tibial tunnel. One method to reduce the graft angulation is to use the anterolateral route tibial tunnel. However, less acute graft angulation may increase joint translation because of a decrease in graft compressive force. The purpose of this study was to compare the graft angulation and joint translation between anteromedial and anterolateral route tibial tunnels. Type of Study: Biomechanical study. Methods: Twelve above-the-knee amputation specimens were used in this study. Anteromedial and anterolateral tibial tunnels were made at the desired locations, and the same femoral tunnel was used. Graft angulation was measured by inserting a malleable pin into the tibial and femoral tunnels. Measurements of graft angulation were performed with the knee in extension and in 90° of flexion. The joint translation was measured by the posterior translation of the tibia on the femur at 90° of flexion with a 15-lb posterior force applied to the anterior proximal tibia after PCL reconstruction through the respective tunnels. Results: The difference in graft angulation between anterolateral and anteromedial route tibial tunnels was statistically significant (P < .001); however, the difference in joint translation showed no statistical significance between the 2 tunnel routes. Conclusions: The anterolateral route tibial tunnel significantly reduced the sharp graft angulation (“killer turn”) at the graft tunnel margin of the proximal tibia, but it did not increase the joint translation as compared with the traditional anteromedial route tibial tunnel. The anterolateral route tibial tunnel is thought to be a better choice when arthroscopic PCL reconstruction is performed with the tunnel technique.     

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.     

Anterior cruciate ligament reconstruction with preservation of remnant bundle using hamstring autograft: technical note

During an arthroscopic examination for an anterior cruciate ligament (ACL) reconstruction, there is a relatively thick remnant ACL tibial stump attached to the posterior cruciate ligament (PCL) or rarely remained between the femur origin and the tibia insertion. We thought that preservation of the remnant ACL original bundle might promote graft healing or be helpful in preserving the proprioception and function to stabilize the knee. Therefore, we established a remnant preservation procedure without additional instruments during an ACL reconstruction using a bio-cross pin (RIGIDfix system: Mitek, Johnson & Johnson, USA) for the femoral tunnel fixation. The remnant ACL was sutured (usually three stitches) using a suture hook (Linvatec, Largo, FL), and both ends of the sutures were pulled to the far anteromedial (AM) portal. These sutures protected the remnant tissue during the ACL reconstruction because medial traction of these sutures can provide a wide view during the reconstruction. After the femoral and tibial tunnel formation, these sutures were pulled out to the inferior sleeve of the cross pin using a previously inserted wire loop via an inferior sleeve. After graft passage, a superior cross pin was first fixed and tibial fixation was then performed. Finally, inferior cross pin fixation was performed and ties were made at the entrance of the inferior cross pin.     

Avulsionsverletzung des Außenmeniskushinterhorns

An avulsion of the posterior tibial insertion of the meniscus (root tear) is a rare clinical diagnosis. Yet, due to the inconsistent clinical symptoms and the difficult arthroscopic assessment, an injury to the root of the meniscus can be easily missed. We present a possible technique for arthroscopic management of root tears using a tibial tunnel approach. A possible injury mechanism could be a rotational distortion of the knee. Another mechanism of injury is an overly posterior tunnel placement in ACL reconstruction. The clinical assessment of the lesion is based on thorough arthroscopic diagnosis of the lateral posterior horn in the figure of 4 position. A tibial ACL aimer can be used to locate a K-wire in the anatomical footprint of the posterior root of the meniscus. After overdrilling using a 4.5-mm drill, two sutures can be passed through the meniscal tissue and the sutures can be pulled out of the tibial tunnel. Extracortical fixation can be used by tying the sutures over a button.A root tear of the meniscus is a difficult clinical and arthroscopic diagnosis. A possibility for refixation of this lesion is to use a tibial tunnel technique. An associated injury to the ACL facilitates the tunnel placement and the suture management.     

One-incision endoscopic technique for posterior cruciate ligament reconstruction with quadriceps tendon–patellar bone autograft

Quadriceps tendon–patellar bone autograft is an alternative graft choice for posterior cruciate ligament (PCL) reconstruction. A 2-incision technique with outside-in fixation at the femoral condyle is generally used. In this article, we describe a 1-incision endoscopic technique for PCL reconstruction with quadriceps tendon–patellar bone autograft. The graft consists of a proximal patellar bone plug and central quadriceps tendon. The bone plug is trapezoidal, 20 mm long, 10 mm wide, and 8 mm thick. The tendon portion is 80 mm long, 10 mm wide, and 6 mm thick, including the full-thickness of the rectus femoris and partial thickness of the vastus intermedius. Three arthroscopic portals, including anteromedial, anterolateral, and posteromedial, are used. All procedures are performed in an endoscopic manner with only 1 incision at the proximal tibia. At the femoral side, the bone plug is fixed by an interference screw. At the tibial side, the tendon portion is fixed by a suture to a screw on the anterior cortex and an interference bioscrew in the posterior tibial tunnel opening. Quadriceps tendon autograft has the advantages of being self-available, allowing for easier arthroscopic technique, and providing comparable graft size. The 1-incision technique provides a simple reconstruction method for PCL insufficiency without a second incision at the medial femoral condyle.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 3 (March), 2001: pp 329–332     

关节镜下复位缝合富血小板血浆注射治疗陈旧性半月板桶柄样撕裂

[目的]介绍陈旧性内侧半月板桶柄样撕裂镜下复位缝合修复,结合富血小板血浆注射的手术技术与初步结果。[方法]对1例28岁陈旧性内侧半月板桶柄样撕裂23年的患者行镜下复位缝合,同时行富血小板血浆注射。镜下全面探查关节内病变,将半月板撕裂部和关节囊残缘打磨出新鲜创面,采用由内向外"U"形缝合半月板2针,牵拉关节外侧缝线,在关节镜直视下松解半月板前、后角挛缩部分,使半月板桶柄撕裂缘与关节囊缘逐渐靠拢,将缝线打结固定。再采用Fast-fix 360将半月板体部至后角撕裂部分全内缝合。探查半月板缝合后撕裂部分复位满意,稳定性良好。将制备好的PRP共4 ml沿内侧膝关节间隙半月板的体部及后角等部位,多点穿刺注射。[结果]术后患者疼痛和关节交锁等症状消失,逐步恢复伤膝活动。术后2个月,患者恢复运动能力,无明显不适,复查MRI显示左膝内侧半月板形态完整、均质,无明显异常信号。[结论]对陈旧性内侧半月板桶柄样撕裂进行适当松解仍可缝合修复,富血小板血浆注射有利于陈旧性半月板缝合修复后愈合。     

Pure Varus Injury to the Knee Joint

A 30-year-old male was involved in a car accident. Radiographs revealed a depressed marginal fracture of the medial tibial plateau and an avulsion fracture of the fibular head. Magnetic resonance imaging showed avulsion fracture of Gerdy''s tubercle, injury to the posterior cruciate ligament (PCL), posterior horn of the medial meniscus, and the attachments of the lateral collateral ligament and the biceps femoris tendon. The depressed fracture of the medial tibial plateau was elevated and stabilized using a cannulated screw and washer. The injured lateral and posterolateral corner (PLC) structures were repaired and augmented by PLC reconstruction. However, the avulsion fracture of Gerdy''s tubercle was not fixed because it was minimally displaced and the torn PCL was also not repaired or reconstructed. We present a unique case of pure varus injury to the knee joint. This case contributes to our understanding of the mechanism of knee injury and provides insight regarding appropriate treatment plans for this type of injury.     

Anteromedial meniscofemoral ligament

We have experienced 3 cases of comparatively rare anteromedial meniscofemoral ligament in which the anterior horn of the medial meniscus was attached to the posterolateral wall of the femoral intercondylar fossa. In 2 of these cases, there was no attachment to the tibia, whereas in the other, it was connected to the lateral meniscus and also firmly to the tibia. In the 2 with no attachment to the tibia, abnormal mobility in the medial meniscus accompanied by flexion and extension of the knee was observed. Degeneration of the intermediate posterior segment and injury of the anterior horn were also observed. This anomaly induces a future meniscus injury, depending on the attachment state to the tibia.     

Limited posterolateral surgical approach to the knee for excision of osteoid osteoma

An 18-year-old man suffered four years of undiagnosed knee pain until a CAT scan revealed an epiphyseal osteoid osteoma of the tibia located subchondrally, just medial to the proximal tibiofibular joint. A nidus in this location is not easily accessible, and its proximity to the joint surface raised concerns about damage to the tibial plateau. To facilitate excision of the tumor, cadaveric dissections were performed to develop a limited posterior approach to the proximal, lateral portion of the tibia. The CAT scan was used to calculate the precise dimensions of the tumor and its relation to the posterior tibial cortex and the proximal tibiofibular joint. With the use of the exposure developed in the laboratory and the calculations derived from the CAT scan, the tumor could be excised by removing a single block of bone 15 mm3. Intraoperative radiographs confirmed the presence of the nidus within the excised block of bone. This case report reaffirms the frequent difficulties and tardiness in diagnosing osteoid osteomas and the need to include these tumors in the differential diagnosis of knee pain and epiphyseal lesions. Before CAT scans were used, the working diagnoses were torn meniscus, juvenile rheumatoid arthritis, and bone hemangiomatosis.     

Posterior root tear fixation of the lateral meniscus combined with arthroscopic ACL double-bundle reconstruction: technical note of a transosseous fixation using the tibial PL tunnel

According to our observation in ACL reconstruction, we find root tears of the posterior horn of the lateral meniscus as a common concomitant injury in ACL-deficient knees. This might be a consequence of initial trauma or of the increased anterior–posterior translation of the tibia and an overload impact on the posterior meniscus root in ACL-deficient knees. A tear of the posterior horn of the medial meniscus causes a 25% increase in peak pressure in the medial compartment compared with that found in the intact condition. The repair restores the peak contact pressure to normal (Allaire et al. in J Bone Joint Surg Am 90(9):1922–1931, [2008]). A tear of the posterior horn of the lateral meniscus might have similar consequences. We hypothesize the surgical anatomical reattachment of the root at the tibia helping to restore knee joint kinematics and helping to advance ACL-graft function. This article presents an arthroscopical technique to reattach the posterior meniscus root in combination with ACL double-bundle reconstruction. The procedure uses the tibial PL tunnel to fix the meniscus suture.     

胫骨骨道定位对前交叉韧带单束重建的影响

[目的]探讨胫骨骨隧道定位对前交叉韧带单束重建术后临床疗效的影响.[方法]将60例前交叉韧带断裂患者随机分为对照组和观察组.对照组胫骨骨隧道内口采用外侧半月板游离缘的切线与前后髁间突连线的交点定位;观察组选择原前内侧束和后外侧束中间位置定位.术后矢状位MRI测量胫骨骨道位置、胫骨纵向位移、后交叉韧带指数、膝关节功能评分进行分析评价.[结果]对照组和观察组胫骨骨道分别位于胫骨平台全长的前(38.67±4.23)％和(34.21±2.46)％.胫骨纵向位移为(11.14±2.64)mm和(14.34±2.23)mm,上倾角为(56.2±4.3)°和(44.6±5.2)°,后交叉韧带指数为(3.97±0.45)和(4.78±0.78);两组比较差异均有统计学意义(t检验,P＜0.05).术后1年,对照组与观察组IKDC膝关节主观评分分别为(79.63±4.67)分和(89.76±5.21)分;Lysholm评分分别为(85.61±4.92)分和(92.54±3.22)分,两组比较差异有统计学意义(t检验,P＜0.05).[结论]前交叉韧带单束重建能使患者的关节稳定性与功能均得到显著改善.膝关节MRI测量可较客观、准确地反映胫骨的骨道定位情况.理想的胫骨骨道在矢状位MRI上位于胫骨平台的前(34.21±2.46)％.     

Impact of medial opening or lateral closing tibial osteotomy on bone resection and posterior cruciate ligament integrity during knee arthroplasty

To compare lateral closing to medial opening wedge high tibial osteotomy regarding change in proximal tibial anatomy and PCL tibial attachment integrity after standard tibial arthroplasty resection. Controlled cadaveric study. Ten cadaveric lower limbs received either a 12° lateral closing or 12.5-mm medial opening wedge high tibial osteotomy. Radiographs were performed before and after each osteotomy, and each PCL tibial attachment was dissected. Postosteotomy, tibial arthroplasty resection was performed and the remaining PCL attachment area calculated. Lateral closing wedge specimens demonstrated a greater change in proximal tibial anatomy. After tibial arthroplasty resection, there was a significant difference in remaining PCL tibial attachment percentage area. Proximal tibial anatomy is altered differently for each type of osteotomy despite similar correction angles. Arthroplasty conversion may be more challenging after lateral closing wedge procedures.     

Posterior instability of the knee joint. An experimental study

We investigated the importance of the posterior cruciate ligament (PCL) and the medial and lateral compartmental structures for translatory and simultaneous axial rotatory instability in 25 osteoligamentous knee preparations. Instability was registered continuously from 0 degree to 90 degrees of flexion with application of a constant force to the tibia. Isolated transection of the PCL increased the posterior tibial displacement with flexion to a maximum of 10 mm at 90 degrees of flexion; when combined lesions to the lateral structures were included, the popliteal tendon (PT) in particular turned out to have a major secondary stabilizing function. The posterior tibial displacement in flexion was doubled when all lateral structures were included in the lesions. Transection of the PCL and all the medial structures led to a notable increment in posterior displacement increasing with flexion. Major increments in simultaneous tibial rotation were recorded only after combined lesions to either medial or lateral structures. A reverse pivot shift was provoked after combined lateral lesions when the PT was included. Even an anteromedial subluxation was released after lesions to the medial structures. Regardless of the type of lesion, the specimens remained stable concerning anterior-posterior displacement in extension. No changes in the anterior tibial displacement were observed.