Femoro-tibial and menisco-tibial translation patterns in patients with unilateral anterior cruciate ligament deficiency--a potential cause of secondary meniscal tears.

OBJECTIVE: To analyze menisco-tibial and femoro-tibial translation patterns in healthy and ACL-deficient knees in different knee flexion angles under muscle activity. METHODS: The ACL-deficient and contralateral healthy knees of 10 patients were examined with an open MRI system at 30 degrees and 90 degrees of knee flexion, under isometric contraction of the extensors or flexor muscle groups. Translations between the tibia, the femoral condyles and the menisci were analyzed by three-dimensional image postprocessing. RESULTS: Posterior translation of the femur and menisci relative to the tibia occurred during knee flexion (30-90 degrees) in all knees. In ACL-deficient knees, posterior translation of the medial femoral condyle (+1.3 +/- 3.8 mm) was significantly larger than in healthy knee (-0.9 +/- 2.9 mm; p<0.05), while the translation pattern of the menisci was similar (med. meniscus 0.6 +/- 2.3 mm vs. 0.6 +/- 2.7 mm). Under isometric contraction of the extensors (relative to the flexor muscle group), an increased posterior position of the femur and menisci was observed at 30 degrees knee flexion, but not at 90 degrees. This applied to ACL-deficient and healthy knees. CONCLUSIONS: This study shows a significant increase of translation of the medial femoral condyle in ACL-deficient knees, whereas menisco-tibial translation remains almost unchanged. This difference in translation patterns indicates that the posterior horn of the medial meniscus might encounter shear, potentially explaining the high rate of secondary medial meniscal tears in patients with ACL-deficiency.     

Effects of the tibial tunnel position on knee joint stability and meniscal contact pressure after double-bundle anterior cruciate ligament reconstruction

BackgroundTo investigate the effect of the tibial tunnel position on knee stability and the maximum contact area and peak contact pressure on the menisci after double-bundle anterior cruciate ligament (ACL) reconstruction.MethodsTen human knee specimens (mean age: 74.1 ± 15.8 years) were used in this study. The anterior tibial loading test was conducted using a material testing machine at 30°, 60°, and 90° of knee flexion, with the anterior tibial translation (ATT) and the maximum contact area and peak contact pressure on the menisci measured. Outcome measures were compared between the following groups: 1) intact ACL (intact group); 2) anatomical tibial tunnel position (anatomical group) and 3) posterior tibial tunnel position (posterior group) with double-bundle reconstruction, and 4) ACL-deficient (deficient group).ResultsIn response to a 100 N anterior tibial load, the ATT was greater for the posterior and ACL-deficient groups compared to that in the intact group. The normalized maximum contact area of the medial meniscus significantly decreased for the posterior group compared to that in the intact group. The normalized peak contact pressure on the medial meniscus increased in all groups compared to that in the intact group, but with no between-group differences in pressure applied to the lateral meniscus.ConclusionsATT and contact pressure on the medial meniscus increased, concomitant with a decrease in contact area of the medial meniscus, as the position of the tibial tunnel position moved towards a posterior position.     

Biomechanical consequences of a posterior root tear of the lateral meniscus: stabilizing effect of the meniscofemoral ligament

Purpose

The purpose of this study was to evaluate the effects of different types of lateral meniscus root tears in terms of tibiofemoral contact stress.

Methods

Ten porcine knees each underwent five different testing conditions with the menisci intact, a simulated lateral posterior root tear with and without cutting the meniscofemoral ligament and with an artificial tear of the posterior root of the medial meniscus. Biomechanical testing was performed at 30° of flexion with an axial load of 100 N. A pressure sensor (st Sensor Type S2042, Novel, Munich) was used to measure the tibiofemoral contact area and the tibiofemoral contact pressure. Data were analyzed to assess the differences in contact area and tibiofemoral peak contact pressure among the five meniscal conditions.

Results

There was no significant difference in mean contact pressure between the state with the menisci intact and an isolated posterior root tear of the lateral meniscus. In case of a root tear and a tear of the meniscofemoral ligament, the contact area decreased in comparison with the intact state of the menisci. After additional cutting of the meniscofemoral ligament, the tibiofemoral contact pressure was significantly higher in comparison with the intact state and the avulsion injury. In the medial compartment, joint compression forces were significantly increased in comparison with the intact state after cutting the posterior root of the medial meniscus (P < 0.05).

Conclusions

The consequence of a medial meniscus root tear is well known and was verified by this analysis. The results of the present study show that the biomechanical consequences of a lateral meniscus root tear depend on the state of the meniscofemoral ligament. An increase in tibiofemoral contact pressure is only to be expected in combined injuries of the meniscus root and the meniscofemoral ligaments.

Clinical relevance

Posterior lateral meniscus root tear might have a better prognosis in terms of the development of osteoarthritis when the meniscofemoral ligament is intact.     

Arthroscopic studies of variants of the anterior horn of the medial meniscus

The objective of this study was to arthroscopically analyse the morphology and dynamics of variants of the anterior horn of the medial meniscus of the knee (VAMM) and to then consider the pathological significance of these variants. VAMM was defined as knees in which the anterior horn of the medial meniscus is not attached to the tibia. Between April 1992 and March 1995, arthroscopy was performed on 953 knees of 903 patients. At the time of this examination, observation and probing were performed to determine the condition of the synovium, the synovial plica, the cartilage in all compartments, the meniscus, the cruciate ligaments, and the popliteal tendon. In particular, detailed examination was made of the anterior horn of the medial meniscus with regard to the point of insertion to the tibia and the degree of movement in knee flexion/ extension. Cases of VAMM diagnosed on the basis of the arthroscopic findings were classified into the following four categories: the ACL (anterior cruciate ligament) type, where the anterior horn of the medial meniscus was attached to the ACL; the transverse ligament type, where the anterior horn of the medial meniscus was attached to the transverse ligament; the coronary ligament type, where the anterior horn of the medial meniscus was attached to the coronary ligament; and the infrapatellar fold type, where the anterior horn of the medial meniscus was attached to the infrapatellar synovial fold. These patients were then analyzed with regard to the arthroscopic findings and the intra-articular lesions other than VAMM. In 98 (10.9%) of the total patients, 103 knees were classified as VAMM. Classification of those 103 knees using the above criteria showed 39 ACL type knees, 51 transverse ligament type knees, 11 coronary ligament type knees, and 2 infrapatellar fold type knees. The arthroscopic findings indicated that the anterior horn of the medial meniscus was not attached directly to the tibia in any of these knees. Probing and flexion/extension of the knee revealed hypermobility at the anterior horn of the medial meniscus. In this study, anterior knee pain syndrome was diagnosed in 12 (11.7%) of the 103 VAMM knees. In addition, there was no clear history of trauma in 20 of 23 knees found to have an isolated medial meniscus tear. In these cases, even detailed arthroscopic observation proved the causes of the symptoms or injury. On the basis of these findings, we surmised that the anterior portion shows hypermobility at the time of flexion/extension of the knee, regardless of the type of VAMM. In this study, we discussed the possibility that the existence of VAMM may become the cause of pain or injury to the meniscus.     

膝关节外侧半月板假撕裂MRI征象分析及临床意义

目的:明确板股韧带及膝横韧带所致外侧半月板假撕裂的发生机制,探讨外侧半月板假撕裂与真撕裂的鉴别方法。方法:对自2012年6月至2014年2月间72例(左膝44例,右膝28例)经关节镜证实的无外侧半月板撕裂的膝关节进行矢状及冠状位MR扫描,其中男41例,女31例;年龄25～61岁,平均33.7岁。观察板股韧带及膝横韧带的MRI表现。结果:膝横韧带与外侧半月板前角及其中央腱性附着部之间以脂肪组织分隔,在MRI矢状像上,可见脂肪组织在膝横韧带与外侧半月板前角之间形成的线样稍高信号裂隙,类似外侧半月板前角撕裂,称为外侧半月板前角假撕裂。板股韧带在矢状像上表现为位于后交叉韧带前或后方的类圆形或短棒状低信号结构,而在冠状像上表现为自外侧半月板后角至股骨内侧髁外侧面的条带样低信号结构。在矢状像上,板股韧带与外侧半月板后角之间显示出一线样高信号,称为外侧半月板后角假撕裂。膝横韧带在MRI上的出现率约34.7%(25/72),表现为外侧半月板前角假撕裂18例,均表现为外侧半月板形态规则、撕裂线斜行,矢状位图像可连续显示膝横韧带,冠状位图像能显示该韧带的长轴。板股韧带显示率为73.6%(53/72),其中板股前韧带为23.6%(17/72),板股后韧带为70.8%(51/72),两条韧带同时存在为16.7%(12/72).表现为外侧半月板后角假撕裂25例,假撕裂仅有两种走行方向,即后下斜行(19/25)或垂直方向(6/25).结论:根据外侧半月板形状、撕裂线方向、观察矢状和冠状位图像,可正确区分外侧半月板的真、假撕裂。     

Combined Injury to the ACL and Lateral Meniscus Alters the Geometry of Articular Cartilage and Meniscus Soon After Initial Trauma

Combined injury to the anterior cruciate ligament (ACL) and meniscus is associated with earlier onset and increased rates of post-traumatic osteoarthritis compared with isolated ACL injury. However, little is known about the initial changes in joint structure associated with these different types of trauma. We hypothesized that trauma to the ACL and lateral meniscus has an immediate effect on morphometry of the articular cartilage and meniscus about the entire tibial plateau that is more pronounced than an ACL tear without meniscus injury. Subjects underwent magnetic resonance imaging scanning soon after injury and prior to surgery. Those that suffered injury to the ACL and lateral meniscus underwent changes in the lateral compartment (increases in the posterior–inferior directed slopes of the articular cartilage surface, and the wedge angle of the posterior horn of the meniscus) and medial compartment (the cartilage-to-bone height decreased in the region located under the posterior horn of the meniscus, and the thickness of cartilage increased and decreased in the mid and posterior regions of the plateau, respectively). Subjects that suffered an isolated ACL tear did not undergo the same magnitude of change to these articular structures. A majority of the changes in morphometry occurred in the lateral compartment of the knee; however, change in the medial compartment of the knee with a normal appearing meniscus also occurred. Statement of clinical significance: Knee injuries that involve combined trauma to the ACL and meniscus directly affect both compartments of the knee, even if the meniscus and articular cartilage appears normal upon arthroscopic examination. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:759-767, 2020     

The effect of complete radial lateral meniscus posterior root tear on the knee contact mechanics: a finite element analysis

Background

In recent years, with technological advances in arthroscopy and magnetic resonance imaging and improved biomechanical studies of the meniscus, there has been some progress in the diagnosis and treatment of injuries to the roots of the meniscus. However, the biomechanical effect of posterior lateral meniscus root tears on the knee has not yet become clear. The purpose of this study was to determine the effect of a complete radial posterior lateral meniscus root tear on the knee contact mechanics and the function of the posterior meniscofemoral ligament on the knee with tear in the posterior root of lateral meniscus.

Methods

A finite element model of the knee was developed to simulate different cases for intact knee, a complete radial posterior lateral meniscus root tear, a complete radial posterior lateral meniscus root tear with posterior meniscofemoral ligament deficiency, and total meniscectomy of the lateral meniscus. A compressive load of 1000 N was applied in all cases to calculate contact areas, contact pressure, and meniscal displacements.

Results

The complete radial posterior lateral meniscus root tear decreased the contact area and increased the contact pressure on the lateral compartment under compressive load. We also found a decreased contact area and increased contact pressure in the medial compartment, but it was not obvious compared to the lateral compartment. The lateral meniscus was radially displaced by compressive load after a complete radial posterior lateral meniscus root tear, and the displacement took place mainly in the body and posterior horn of lateral meniscus. There were further decrease in contact area and increases in contact pressure and raidial displacement of the lateral meniscus in the case of the complete posterior lateral meniscus root tear in combination with posterior meniscofemoral ligament deficiency.

Conclusions

Complete radial posterior lateral meniscus root tear is not functionally equivalent to total meniscectomy. The posterior root torn lateral meniscus continues to provide some load transmission and distribution functions across the joint. The posterior meniscofemoral ligament prevents excessive radial displacement of the posterior root torn lateral meniscus and assists the torn lateral meniscus in transmitting a certain amount of stress in the lateral compartment.     

Meniscal lesions in so-called "isolated" ruptures of the anterior cruciate ligament. Apropos of 59 cases

Between December 1984 and March 1987, i.e. a period of 27 months, the authors operated on 59 "isolated" fresh ruptures of the ACL with routine evaluation of the posterior horns of the medial and lateral menisci. Lesions were investigated either by arthroscopy (23 cases) or by anterior arthrotomy with routine medial and lateral retro-ligamentous counter-incision (36 cases). This revealed 21 lesions of the medial meniscus (i.e. 35.5%) and 38 lesions of the lateral meniscus (i.e. 64.5%). Lesions of both menisci were present in 16 knees (27%) and only 16 knees (27%) were found to be free of any meniscal lesion. The majority of meniscal lesions were viable and could be sutured in 86% of cases for the medial meniscus and 87% of cases for the lateral meniscus. From the standpoint of operative technique, posterior lesions are relatively poorly visualized by arthroscopy (notably concerning the posterior horn of the medial meniscus though it is easier to assess the stability of the meniscus by this technique using the palpating hook. Lesions are well visualized by medial and lateral retroligamentous counter-incisions, but it is difficult to assess meniscus stability. Finally it should be noted that all of these ruptures of the ACL were dealt with by reconstruction of the central pivot either by suture and a strengthening procedure (semitendinous) or by ligament plasty from the outset.     

MRI analysis of in vivo meniscal and tibiofemoral kinematics in ACL-deficient and normal knees.

The objectives of this study were to analyze simultaneously meniscal and tibiofemoral kinematics in healthy volunteers and anterior cruciate ligament (ACL)-deficient patients under axial load-bearing conditions using magnetic resonance imaging (MRI). Ten healthy volunteers and eight ACL-deficient patients were examined with a high-field, closed MRI system. For each group, both knees were imaged at full extension and partial flexion ( approximately 45 degrees ) with a 125N compressive load applied to the foot. Anteroposterior and medial/lateral femoral and meniscal translations were analyzed following three-dimensional, landmark-matching registration. Interobserver and intraobserver reproducibilities were less than 0.8 mm for femoral translation for image processing and data analysis. The position of the femur relative to the tibia in the ACL-deficient knee was 2.6 mm posterior to that of the contralateral, normal knee at extension. During flexion from 0 degrees to 45 degrees , the femur in ACL-deficient knees translated 4.3 mm anteriorly, whereas no significant translation occurred in uninjured knees. The contact area centroid on the tibia in ACL-deficient knees at extension was posterior to that of uninjured knees. Consequently, significantly less posterior translation of the contact centroid occurred in the medial tibial condyle in ACL-deficient knees during flexion. Meniscal translation, however, was nearly the same in both groups. Axial load-bearing MRI is a noninvasive and reproducible method for evaluating tibiofemoral and meniscal kinematics. The results demonstrated that ACL deficiency led to significant changes in bone kinematics, but negligible changes in the movement of the menisci. These results help explain the increased risk of meniscal tears and osteoarthritis in chronic ACL deficient knees.     

What is the terrible triad?

In 1936 Campbell asserted that "impairment of the anterior crucial and mesial ligaments is associated with injuries of the internal cartilage." O'Donoghue in 1950 called attention to "that unhappy triad (1) rupture of the medial collateral ligament, (2) damage to the medial meniscus, and (3) rupture of the anterior cruciate ligament" and recommended early surgical intervention. In 1955 he reported 33 cases with both medial collateral (MCL) and anterior cruciate ligament (ACL) tears, but there were only three lateral meniscus tears reported. Based on a recent report by Shelbourne and Nitz that questions the validity of this unhappy triad, a review of all arthroscopically confirmed acute injuries of second degree or worse to the ACL and MCL was undertaken. Of a total of 52 knees reviewed, 50 knees had third-degree ACL tears and two had second-degree ACL tears. One of the second-degree tears was associated with a second-degree MCL and one with a third-degree ACL tear. Neither had an associated meniscus tear. Forty-five third-degree ACL tears were associated with third-degree MCL tears (group 1) and five with second-degree MCL tears (group 2). Eighty percent (36 knees) of group 1 had lateral meniscus tears. Only 29% of group 1 (13 knees) had associated medial meniscus tears. None of these medial meniscus tears was isolated. Eighty percent (four knees) of group 2 had lateral meniscus tears with only one associated medial meniscus tear. Again, there were no medial meniscus tears in the absence of a lateral meniscus tear. We did not find the combination of injury originally described as the unhappy triad.     

Anatomical relationship between insertion sites,tunnel placement,and lateral meniscus anterior horn injury during single and double bundle anterior cruciate ligament reconstructions: A comparative macroscopic and histopathological evaluation in cadavers

PurposeThe influence of tunnel extension outside the anatomical anterior cruciate ligament (ACL) insertion in single-bundle (SB) or double-bundle (DB) ACL reconstruction is unclear. This study aimed to investigate the anatomical relationship between ACL insertion and tunnel extension in SB and DB ACL reconstruction, and the impact of tibial tunnel extension to the insertion of anterior horn of lateral meniscus in terms of injury.MethodsForty-six paired cadaver knees (mean age, 82.7 ± 10.7 years) were used. Right and left knees were used for SB (10 mm) and DB tunnel reaming (6 mm for the anteromedial and posterolateral bundles). Tibial and femoral tunnels were created to aim at the center of the ACL insertion by arthroscopic visualization. The relationship between tunnel extension and ACL insertion was evaluated macroscopically, and there ratio in two groups were compared by chi-square test. Further, the relative risk for meniscus injury based on tunnel placement was estimated. Coronal section of tibia and parallel section to Blumensaat line in femur were prepared to evaluate the relationship among tunnel position, ACL insertion, and anterior horn of the meniscus histologically.ResultsTibial tunnel extension out of the ACL insertion was observed macroscopically in 9 (39.1%) knees of the SB group, and 3 (13.0%) of the DB group (p = 0.045). In femoral tunnels, extension out of the ACL insertion was seen in 8 (34.8%) knees of the SB group and 1 (4.3%) of the DB group (p = 0.011). Partial injuries of the lateral meniscus anterior horn (LMAH) were observed in 5 (21.7%) knees of the SB group and 1 (4.3%) knee of the DB group (p = 0.091). The relative risk for LMAH injury was calculated as 5.0 (odds ratio, 6.1). Microscopically, SB tunnels appeared to expand out of ACL insertion, both in the femur and tibia.ConclusionsThe incidence of tunnel extension out of the ACL insertion in femur and tibia were higher with SB than with DB reconstruction. Furthermore, injury rate of the LMAH in the DB group was lower.     

Double transosseous pull out suture technique for transection of posterior horn of medial meniscus

Transection injury (complete radial tear, root tear) in the posterior horn of medial meniscus will lead to loss of hoop strain, extrusion of the meniscus and early degenerative changes. The posterior horn of medial meniscus is amenable to repair due to its good blood supply and repair is the procedure of choice for these injuries. In cases of transection of the medial meniscus posterior horn, the meniscus can be repaired by a pull out suture technique using trans-septal portal. The single transosseous pull out suturing technique is a point fixation technique with limited contact area having low and inhomogeneous contact pressure. This article describes a double transosseous pull out suture technique using trans-septal portal for the repair of transection of posterior horn of medial meniscus. Use of double transosseous technique provides more secure fixation, more homogeneous and wider contact pressure area between meniscus and the bone, improving the healing potential of the repair.     

关节镜下自体骨-髌腱-骨重建膝前交叉韧带

目的评价关节镜下用自体中1／3骨-髌腱-骨重建膝前交叉韧带的技术和效果。方法自2000年10月至2006年12月共65例经关节镜检查证实为前交叉韧带断裂,36例伴半月板撕裂,22例伴内侧副韧带损伤,7例伴后交叉韧带断裂。男45例,女20例;年龄20-45岁,平均29．13岁。左膝38例,右膝27例。急性损伤30例,陈旧性损伤35例。均于关节镜下行自体中1／3骨-髌腱-骨前交叉韧带重建术,采用Biofix生物可吸收界面螺钉解剖位固定重建韧带。同时,在关节镜下处理合并损伤。术后早期行CPM功能锻炼。结果术后早期均未发生严重并发症。所有患者获得随访,随访1～5年,平均3,8年。采用Lysholm评分标准评价膝关节功能,术前平均58．36分（45-80分）,术后平均92．77分（70～100分）。术后与术前相比差异有显著性（P〈0．0001）。65例患者中,61例恢复伤前运动水平,4例运动水平较伤前减低。结论该手术创伤小、关节内环境影响小,可同时进行关节内其他手术,术后功能恢复快,是重建膝前交叉韧带的有效方法。     

Bilateral PCL hypoplasia resulting in posterior, posterolateral rotatory instability and tears of the lateral meniscus anterior horn

This article describes a case of bilateral sagged knees presenting as posterior, posterolateral rotatory instability with tears of the anterior horn of the lateral meniscus. Each knee had identical tears of the lateral meniscus anterior horn. A 42-year-old woman reported bilateral anterior knee pain and painful instability during running or jarring exercises. She reported no major trauma to her knees. Arthroscopic findings of her right knee revealed a posterior cruciate ligament that looked hypoplastic but was without acute injury, and the anterior horn of the lateral meniscus showed chronic complex tears with some degeneration. Posterior cruciate ligament reconstruction, posterolateral corner sling, and meniscal repair of the lateral meniscus anterior horn was performed on her right knee. Three months later, a similar operation was performed on her left knee. However, menisectomy was performed because the lateral meniscus anterior horn tear was in the junction of the red-white and white zones. At 18 months postoperatively, the patient reported no symptoms and was satisfied with her results. Physical examination showed no joint line tenderness, and posterior stress radiographs on both knees showed grade I posterior instability. She showed no posterolateral subluxaion by supine dial test, and her prone dial test also improved approximately 15° on both knees. Lysholm score was 74 preoperatively and improved to 92 postoperatively.     

Die arthroskopische Meniskusrefixation mit einem All-inside-Nahtsystem

OBJECTIVE: Application of an arthroscopic suture system to restore the form and function of the meniscus by adaptation of a longitudinal tear close to the base. INDICATIONS: Unstable longitudinal tears near the base of the meniscus, mainly in the posterior horn of the medial or lateral of the meniscus. Dislocated bucket-handle tears of the medial and lateral meniscus close to the base. CONTRAINDICATIONS: Poor tissue quality with fibrillated meniscal tissue. Meniscal tears in the avascular zone (zone I). Insufficient blood supply from the joint capsule and the base of the meniscus. Degenerative meniscal lesions. Anterior or posterior knee joint instability. Allergic reactions to nonresorbable suture material. SURGICAL TECHNIQUE: Standard anterior arthroscopic portals. Arthroscopic assessment of the meniscal tear using the probe. Revitalization of the tear margins and perforation of the meniscal base to induce bleeding. Adaptation of the tear margins and fixation with a suture-anchor system using an ipsilateral standard portal for tears in the posterior horn or by way of a contralateral standard portal for tears in the lateral horn. POSTOPERATIVE MANAGEMENT: Full weight bearing with the knee in extension in a knee immobilizer, relative to the pain threshold in the 1st postoperative week. Range of motion exercises without weight bearing from full extension to 90 degrees knee flexion (0/0/90). If simultaneous reconstruction of the anterior cruciate ligament (ACL) is being performed, rehabilitation protocols follow the principles for ACL reconstruction. RESULTS: Since the year 2000, meniscal tears in more than 300 patients have been repaired with the all-inside suture system. In the context of a multicenter study by ESSKA (European Society for Sports Medicine, Surgery and Arthroscopy) involving 20 patients, the result was evaluated by direct MRI arthrography (gadolinium). The suture bar anchors were generally not detectable, the incision channels produced a hypodense signal in the meniscus tissue. If re-rupture occurred, it was because the meniscus had pulled out of the suture loop. Cartilaginous lesions were not found. There were no complications related to the nonresorbable suture bar anchors.     

膝关节内外侧半月板后根部撕裂的MRI诊断价值

目的:探讨MRI对膝关节内外侧半月板后根部撕裂的诊断价值。方法:回顾性分析2012年1月至2016年1月,关节镜下证实为半月板后根部撕裂的患者43例。其中男25例,女18例;年龄27~69(42.5±8.3)岁;右侧27例,左侧16例。由2名医师采用双盲法独立回顾性分析经关节镜证实的43例半月板后根部撕裂患者的MRI表现,计算MRI对半月板后根部撕裂的诊断敏感性、特异性和准确性,并计算膝关节韧带损伤及半月板脱位等伴随情况。结果:143例中,关节镜手术证实43例半月板后根部撕裂,包括内侧撕裂24例,外侧撕裂19例。医师A诊断内侧半月板后根部撕裂的敏感性、特异性、准确性分别为91.67%、86.6%、83.9%,伴内侧半月板突出19例,伴前交叉韧带撕裂2例;外侧半月板后跟部撕裂的敏感性、特异性、准确性分别为73.7%、79.9%、79%,伴外侧半月板突出4例,伴前交叉韧带撕裂16例。医师B诊断内侧半月板后根部撕裂的敏感性、特异性、准确性分别为87.5%、87.4%、87.4%,伴内侧半月板突出19例,伴前交叉韧带撕裂2例;外侧半月板后跟部撕裂的敏感性、特异性、准确性分别为78.9%、82.3%、82.5%,伴外侧半月板突出4例,伴前交叉韧带撕裂16例。2名医师采用MRI诊断内、外侧半月板后根部撕裂的一致性均好,Kappa值分别为0.81和0.67。结论 :膝关节MRI诊断内外侧半月板后跟部撕裂及其伴随征象具有较大价值,为临床医生术前诊断提供依据,值得临床推广应用。     

半月板撕裂和切除对前交叉韧带断裂力学稳定性的影响

目的探讨半月板对前交叉韧带断裂及重建术后胫骨前向稳定性的影响。 方法收集2017年1月至2018年10月期间前交叉韧带重建患者,排除前交叉韧带部分断裂和多发韧带损伤病例。所有不稳定半月板撕裂均行半月板部分切除术,根据半月板损伤部位及程度进行分组。采用KT-1000测量术前、术后3个月和6个月的胫骨前平移量(ATT)。组间对照采用独立样本t检验。 结果共纳入158例前交叉韧带断裂患者,其中半月板正常组61例,内侧半月板后角撕裂组49例(19例为撕脱<总宽度40%;30例为撕脱≥总宽度40%);外侧半月板撕裂组35例(12例为撕脱<总宽度40%;23例为撕脱≥总宽度40%);内侧半月板前角或体部撕裂组13例(6例为撕脱<总宽度40%;7例为撕脱≥总宽度40%)。术前内侧半月板后角撕裂≥总宽度40%患者的胫骨前平移量较半月板正常患者明显增加,差异有统计学意义(t＝12.141,P<0.01)。术后3个月及6个月,各个半月板撕裂组的ATT值与半月板正常患者相比均无差异(P >0.05)。 结论内侧半月板后角撕裂与前交叉韧带断裂可增加膝关节的不稳定性,半月板部分切除术对前交叉韧带重建术后患者的膝关节稳定性无影响。     

Medial and lateral segond fractures in a skeletally immature patient: a radiographic marker for the multiply injured knee

Marginal fractures of the medial tibial plateau have been reported in the literature as a secondary type of Segond fracture. Some reports described this entity in the setting of combined injuries such as root avulsions of the medial meniscus, complete disruption of the posterior cruciate ligament (PCL), partial tear of the anterior cruciate ligament (ACL), and tears of the medial meniscus and medial collateral ligament. It has been postulated that medial marginal fractures are secondary to compression of the medial aspect of the femoral condyle and tibial plateau with a corresponding posterolateral corner injury. However, this mechanism of injury may not always be as straightforward.This article presents a case of an alternate injury pattern in a skeletally immature patient. A 16-year-old boy sustained a varus force and twisting injury to his knee, resulting in radiographic evidence of multiple avulsion fractures of the knee, including a fibular epiphyseal avulsion fracture and medial and lateral Segond fractures. Usually, the avulsion fractures serve as markers for significant ligamentous injuries in adult patients, but our patient had minimal injury to the PCL, ACL, and posterolateral corner. Further physical examination and imaging studies revealed an anterior horn root avulsion, meniscocapsular separation, and anterior cortical rim fracture. A combination of imaging modalities helped us further characterize the injury pattern to devise the optimal surgical plan, especially the fixation of the anterior cortical fracture of the tibia.     

膝关节半月板撕裂的磁共振表现

目的进一步认识膝关节半月板撕裂的磁共振成像(MRI)表现。方法回顾分析50例膝关节半月板撕裂的MRI资料,所有病例均经关节镜手术证实。采用永磁型MRI机,场强0.2T。结果50例半月板撕裂中,按照部位分类,半月板撕裂位于内侧半月板前角2例,内侧后角37例,外侧半月板前角5例,外侧后角3例,同时累及半月板前角、体部和后角者内侧2例,外侧1例。按照半月板撕裂的形式分为:水平撕裂8例;垂直撕裂4例;斜形撕裂26例;纵形撕裂3例;放射状撕裂4例;桶柄状撕裂2例;复杂撕裂3例。结论MRI能够清楚显示膝关节半月板撕裂的部位和形式,为临床治疗提供可靠的依据,是目前诊断半月板撕裂的最好的影像学检查方法。