Meniscal ossicle: a case report

Meniscal ossicle is a cortical or cancellous tissue with central viable marrow surrounded by meniscal cartilage. We present a case of medial meniscal ossicle at its posterior horn. A 21-year-old male military recruit visited our clinic due to left knee discomfort. He had not undergone any notable injury on the knee, but complained of intermittent catching or giving way without locking. Simple radiographs showed a small round bony fragment at posteromedial side of knee joint. The magnetic resonance imaging revealed an intra-substance lesion of meniscus, whose signal is identical to bone. On arthroscopy, the articular cartilage of medial femoral condyle and tibial plateau appeared degenerative with a groove-like scar. The medial meniscus seemed swollen at the posterior horn, but there was no discernible tear in the adjacent meniscus. After piecemeal removal of meniscal substance, a small osseous fragment was identified, which was evacuated via posteromedial portal. The resection of meniscus amounted to a subtotal meniscectomy. The activities of daily living were possible without any trouble even after 9 months of follow-up. This entity should be distinguished from intra-articular loose body, and included in the differential diagnosis of the incidental findings of small ossified density around knee joint.     

Can an injured discoid lateral meniscus be returned to the correct anatomic position and size of the native lateral meniscus after surgery?

BackgroundNo previous studies have compared the position and size of the remaining discoid lateral meniscus (DLM) with that of a normal lateral meniscus. This study aimed to evaluate the postoperative position and size of DLM compared with that of normal controls using magnetic resonance imaging (MRI).MethodsThis retrospective study involved 52 symptomatic complete type DLMs (discoid group) who underwent arthroscopic surgery and 50 normal controls (control group). Pre- and postoperative MRI evaluations, height, width, and relative percentage of extrusion (RPE) were assessed. Sagittal position parameters, including distances from articular cartilage center to anterior meniscus (CAMD) and from anterior articular cartilage margin to anterior horn (ACMD), were also assessed. Logistic regression analysis was performed to find factors with extrusion of remaining DLM.ResultsThe height of the discoid group was significantly lower than that of the control group (P = 0.000). RPE in the discoid group was significantly larger than in the control group (P = 0.005). Only CAMD and ACMD in the discoid group were different (positioned more anteriorly) from the control group (P = 0.000). Preoperative meniscal shift (odds ratio (OR): 12.448; P = 0.003) and operative technique, especially partial meniscectomy with repair (OR: 19.125; P = 0.000), were the major factors associated with extrusion.ConclusionThe width of remaining DLM was comparable to that of normal controls, but the position was found to be more anterior and lateral than that of normal controls. Preoperative meniscal shift and combined meniscus repair were the major factors for smaller width and greater extrusion; thus, surgeons should address and counsel these factors before surgery.     

半月板部分切除后胫股关节接触面积及生物力学变化

背景：生物力学实验有助于阐明为何半月板切除后会导致进行性的软骨病变。关节软骨退行性变的原因复杂,包括生物学、力学以及结构通路等。 目的：研究内侧半月板后角撕裂行半月板部分切除后胫股关节接触面积、压力及半月板应变的变化。 方法：取8具新鲜冷冻的混合品种的狗后肢膝关节标本,序贯进行以下半月板切除操作,采取百分比来计算每一样本半月板切除的范围：①内30%的内侧半月板后角撕裂。②内75%的内侧半月板后角撕裂。③内侧半月板后角完全切除。用双轴液压伺服生物材料测试实验机(MTS 858)进行生物力学测试。统计学比较采用SPSS 18.0软件进行组间比较。 结果与结论：半月板组织切除越多,内侧和外侧胫股关节接触面积下降越明显,内侧半月板后角切除75%和全切后,内侧接触面积差异无显著性意义(P > 0.05);内侧半月板后角完全切除之后,外侧接触面积显著减少。内侧半月板后角切除75%和全切之后,内侧间室的接触压力显著升高,与对照组相比差异有显著性意义(P < 0.05),内侧半月板后角完全切除后外侧间室接触压力显著降低(P < 0.05)。因为半月板组织的切除,其相应的应变下降,但是各组间差异无显著性意义。说明半月板切除多少决定术后半月板的生物力学功能;对于半月板撕裂,尤其是“红区”损伤,应尽量选择半月板缝合术,减少半月板切除范围,以避免或者延缓膝关节的退行性变。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Localized pigmented villonodular synovitis in the knee associated with locking symptoms

Pigmented villonodular synovitis (PVNS) occurs in the knee more frequently than other joints. Most cases involve diffuse PVNS while the localized type is relatively rare. This report describes a patient who had PVNS and a lateral meniscus injury which induced locking symptoms in the knee. A closed reduction of the meniscus tear was performed under local anesthesia. However, complete extension of the knee was not achieved and the locking symptoms persisted. MRI examination showed a neoplastic lesion measuring approximately 2 x 2 cm in the intercondylar space together with a lateral meniscus tear. The lesion was resected using arthroscopy. Histology of the resected lesion demonstrated localized PVNS. There has not been any recurrence of locking symptoms or PVNS two years after surgery. The findings in this case suggest that localized PVNS may contribute to locking symptoms in a patient with meniscal pathology.     

Is formal decompression necessary for parameniscal cysts associated with meniscal tears?

BackgroundMeniscal tears and associated parameniscal cysts have good outcomes after partial meniscectomy and cyst evacuation. Good outcomes have been noted after partial meniscectomy with recurrent cysts. This investigation asks if partial meniscectomy without meniscal cyst decompression is sufficient for positive patient outcome.MethodsSixteen patients treated between 2005 and 2010 for a meniscal cyst and concomitant meniscal tear. Inclusion criteria were meniscal tear and parameniscal cyst per MRI, no prior surgery on the affected knee, and Outerbridge classification of I/II. Two patients were excluded. Fourteen patients completed the study until final follow-up. Lysholm knee scores were documented at 6 months post-operatively and at final follow-up. Re-evaluation or second surgery of the treated knee was documented.ResultsEight lateral cysts and six medial cysts were diagnosed. Eight cysts were associated with a horizontal cleavage tear, while six menisci had a complex tear with a horizontal cleavage component. The average cyst size was 1.3 cm (0.5 to 3.5) at the largest diameter. At 6 months, the average Lysholm knee score was 94.1. At mean 5 years, the average score was 89.1. Patients with medial cysts, cysts greater than 1.0 cm, horizontal cleavage tears, or without simultaneous chondroplasty scored higher in the short and medium-term than their respective counterparts.ConclusionsExcellent short and medium-term outcomes can be achieved following partial meniscectomy without cyst decompression for patients with meniscal cysts and associated meniscal tears.Level of evidenceLevel IV     

The role of meniscal tears and meniscectomy in the mechanical stability of the anterior cruciate ligament deficient knee

Background

The role of an intact meniscus in providing mechanical stability to the knee of anterior cruciate ligament (ACL) deficient and ACL reconstructed patients has not been well studied.

Lateral meniscal tear resulting from the femoral cross-pin used for hamstring graft fixation in anterior cruciate ligament reconstruction

We report a case of lateral meniscal tear resulting from the femoral cross-pin used for hamstring graft fixation in anterior cruciate ligament (ACL) reconstruction. A 29 year old man presented with symptoms of knee pain, catching and locking, 13 months following an ACL reconstruction. Magnetic resonance imaging (MRI) and arthroscopy confirmed the broken femoral cross-pin abutting the lateral meniscus and the resulting meniscal tear. Removal of the broken femoral cross-pin and repair of the lateral meniscal tear resulted in resolution of symptoms. Distal femoral cross-pin fracture and its intra-articular position are postulated as the cause of this lateral meniscal tear. Hence, we recommend a low threshold to investigate with a MRI scan any new symptoms following ACL reconstruction with cross-pin fixation.     

Meniscal pullout repair following meniscal ossicle resection: A case report

We present this case of a meniscal ossicle of the posterior horn of the medial meniscus that was treated by an arthroscopic ossicle resection followed by a pullout repair of the remaining meniscus. A 49-year-old businessman complained of catching and left knee pain. Radiographic and arthroscopic findings revealed a meniscal ossicle embedded in the posterior horn of the medial meniscus and posterior horn tear. After resection of the posterior horn with the ossicle, a pullout suture repair for the posterior segment of the meniscus was done to minimize the further extrusion of the meniscus. A histologic appearance supported the vestigial development of the meniscal ossicle as the etiology. This is the first report describing a repair of the meniscus after ossicle resection.     

An 11-year-old girl presenting with chronic knee pain: a case report with diagnostic dilemma

Discoid meniscus is the commonest anatomical aberration of the knee joint, among rare cases such as bilateral separated lateral meniscus, accessory lateral meniscus, partial deficiency of the lateral meniscus and double-layered lateral meniscus. An 11-year-old girl presented with history of chronic pain in her right knee for the last 6 months. The problem disturbed her involvement in the sport activities at school. Clinical examination revealed a clicking sensation on knee extension with lateral joint line tenderness. Magnetic resonance imaging (MRI) of her right knee showed torn posterior horn of lateral meniscus. Arthroscopy examination revealed a discoid meniscus with absence posterior horn. Posterior horn deficient discoid meniscus is a rare form of a congenital meniscus anomaly. We as clinicians believe that the abnormal shaped meniscus may pose a diagnostic challenge clinically and radiologically. Presentation of this case may be beneficial for orthopaedicians in their daily clinical practice.     

A lateral meniscus tear incarcerated behind the popliteus tendon: A case report

A 51-year-old male, sustained an injury to his left knee after being pinned between his motorcycle and a road barrier. In the ER, the patient complained of medial knee pain, and had a significant joint effusion. MRI demonstrated an ACL injury, medial meniscal tear, bone bruising and impaction at the lateral femoral condyle and tibial plateau, and a tear of the posterior horn of the lateral meniscus that was displaced behind the popliteus. Unfortunately, the patient also presented with a deep vein thrombosis and thus could not proceed to the operating room for two months. During this time, scar tissue developed around the lateral meniscus.The purpose of this report is to present an unusual variant of a common injury pattern previously unreported where the posterior horn of the lateral meniscus became incarcerated behind the popliteus tendon and was left in place. It is likely that our patient will develop osteoarthritis in the future, but considering the circumstances he received a favorable early clinical outcome. Early recognition and a mobile fragment are essential restoring a patient's original anatomical features and achieving an optimal clinical outcome.     

膝关节半月板根部MRI影像解剖

目的 总结半月板根部的MRI解剖特点,确定半月板主体部分与根部的分界。方法 收集2012年10月—2014年2月保定市第一中心医院骨科24例经关节镜证实正常半月板根部的膝关节MRI资料和1例男性成人患者因下肢动脉硬化而截肢的新鲜膝关节标本,对半月板根部的MRI解剖行前瞻性研究,总结半月板根部MRI的形态、走行及附着点的位置,分析信号特点,并测量根部的长度、宽度、高度以及各根部走行角度。另在新鲜膝关节标本上确定半月板主体部分与根部的分界并用铜丝标示之,对标本行MRI扫描。结果 24例患者膝关节MRI显示:内侧半月板后根部呈梳状斜向下走行,信号较半月板主体部分稍高,附着于髁间后区;外侧半月板后根部较内侧半月板后根部明显长,走行于髁间隆起,附着于内侧髁间隆起的外侧面,信号与半月板主体部分类似;内侧半月板前根部较细,附着于髁间前区最前缘,为低或较低信号;外侧半月板前根部呈梳状稍向下向后走行,信号稍高,附着于髁间前区并稍向外下方倾斜的骨表面。各根部测量数据显示:横断面外侧半月板后根部最长,为(15.74±2.03)mm;冠状面内侧半月板后根部最短,为(7.88±1.57)mm;外侧半月板后根部走行与标准冠状面扫描线的夹角角度最大,为34.00°±9.24°。1例新鲜标本MR扫描图片清晰,半月板主体部分与根部分界标记显示清晰。结论 内外侧半月板前后根部各有其特点,MRI能够清晰显示半月板根部的形态、走行、信号特点及附着点位置。     

Tendinous insertion of semimembranosus muscle into the lateral meniscus

Forty-two cadaver knees were used for morphologic and MRI observations of the tendinous distal expansions of the semimembranosus m. and the posterior capsular structures of the knee. A tendinous branch of the semimembranosus m. inserting into the posterior horn of the lateral meniscus was found in 43.2% of the knees dissected, besides five already known insertional branches; capsular, direct, anterior and inferior, as well as the oblique popliteal ligament. The tendon had three morphologic types; thin, broad and round. All three types moved the lateral meniscus posteriorly when pulled on. Thus, the semimembranosus m. may also have a protective function for the lateral meniscus as well as the already well established function of protecting the medial meniscus in knee flexion. When a semimembranosus tendon attachment to the posterior horn of the lateral meniscus is present, its normal insertion is difficult to differentiate from a lateral meniscus tear in MRI and this may cause misdiagnosis.     

半月板和交叉韧带矢状断层研究

目的　观察膝关节矢状断层的半月板和交叉韧带的形态、可出现的层面情况并测量有关数据 ,为影像学诊断提供解剖学依据。方法　 11例 (2 2侧 )经福尔马林液防腐的膝关节标本按MRI检查姿势标线 ,冷冻后用断层带锯作厚 5mm的矢状断层 ,获得 314断层 (观察 5 84层面 ) ,对各断层面的半月板和交叉韧带进行观察 ,并用电子游标卡尺进行测量。结果　半月板后角高度明显高于前角 (P <0 0 1) ,内侧半月板后角宽度约是前角的 2倍 ,而外侧半月板宽度前、后角基本一致 ,外侧半月板体部宽于内侧且更靠近中轴 ,盘状半月板主要发生于外侧 ;正中矢状面显示交叉韧带全长的出现率为 82 % ,其全长的最好层面为正中矢状面和正中旁 1cm层面 ;前交叉韧带与矢状面的夹角较后交叉韧带小 ;前、后交叉韧带在股骨和胫骨的附着点宽约 12mm ,各附着点宽差异无显著性 (P >0 0 5 )。结论　膝关节矢状断层形态学研究提示半月板的后角容易损伤 ;外侧半月板后角明显较内侧窄而高 ,此为临床所见外侧半月板较内侧半月板更易损伤的形态学基础。     

The double flipped meniscus sign: Unusual MRI findings in bucket-handle tear of the lateral meniscus

Bucket-handle meniscal tears are either longitudinal, vertical, or oblique in direction with an attached tear fragment displaced from the meniscus. Magnetic resonance imaging (MRI) signs are widely used in the diagnosis of these tears, including the ‘fragment within the intercondylar notch sign’, ‘flipped meniscus sign’, ‘double anterior horn sign’, ‘absence of the bow tie sign’, ‘double posterior cruciate ligament (PCL) sign’, ‘posterior double PCL sign’, and ‘triple PCL sign’. We report an unusual case, not yet described in previous studies, of a bucket-handle tear presenting as a double longitudinal tear of the lateral meniscus (LM). Two longitudinal tears were observed in the white–white zone and the red–white zone of the LM, where both fragments were shown to be displaced and locked within the intercondylar notch. Partial menisectomy was performed for the central fragment and a repair with modified all-inside sutures was performed for the peripheral fragment.     

Indications requiring preoperative magnetic resonance imaging before knee arthroscopy

Introduction

Knee arthroscopy knee is gold standard in diagnosis and simultaneous treatment of knee disorders. But most patients undergo magnetic resonance imaging (MRI) before arthroscopy, although MRI results are not always consistent with arthroscopic findings. This raises the question in which suspected diagnoses MRI really has influence on diagnosis and consecutive surgical therapy.

Material and methods

Preoperative MRI of 330 patients with knee disorders were compared with arthroscopic findings. The MRI were performed by 23 radiologists without specialization in musculoskeletal diagnostics. Specificity, sensitivity, negative/positive predictive value and accuracy of MRI were calculated in comparison to arthroscopic findings.

Results

We found sensitivity/specificity of 58%/93% for anterior horn, 94%/46% for posterior horn of medial meniscus and 71%/81% for anterior and 62%/82% for posterior horn of lateral meniscus. Related to anterior cruciate ligament injuries we showed sensitivity/specificity of 82%/91% for grade 0 + I and 72%/96% for grade II + III. For Cartilage damage sensitivity/specificity of 98%/7% for grade I-, 89%/29% for grade II-, 96%/38% for grade III- and 96%/69% for grade IV-lesions were revealed.

Conclusions

The MRI should not be used as routine diagnostic tool for knee pain. No relevant information for meniscal lesions and anterior cruciate ligament ruptures has been gained with MRI from non-specialized outside imaging centres.The MRI should not be used as routine diagnostic tool for knee pain. No relevant information for meniscal lesions and anterior cruciate ligament ruptures has been gained with MRI from non-specialized outside imaging centres.     

Repair of a radial tear in the posterior horn of the lateral meniscus

BackgroundThere have been no studies evaluating the clinical results after repair of a radial tear in the posterior horn of the lateral meniscus (PHLM) using the FasT-Fix system. This study was undertaken to evaluate the clinical outcomes after repair of a radial tear in the PHLM using the FasT-Fix system in conjunction with anterior cruciate ligament (ACL) reconstruction.MethodsBetween September 2008 and August 2011, 15 radial tears in the PHLM identified during 132 consecutive ACL reconstructions were repaired using the FasT-Fix meniscal repair system. We classified the radial tears into three types according to the tear patterns: simple radial tear, complex radial tear, and radial tear involving the popliteal hiatus. Postoperative evaluation was performed using the Lysholm knee score and Tegner activity level. Second-look arthroscopy was performed in all cases.ResultsThe mean follow-up period was 24 months. None of the patients had a history of recurrent effusion, joint line tenderness or a positive McMurray test. The meniscal repair was considered to have a 100% clinical success rate. At the final follow-up, the Lysholm knee score and Tegner activity level were significantly improved compared to the preoperative values. On the second-look arthroscopy, repair of radial tears in the PHLM in conjunction with ACL reconstruction using the FasT-Fix device resulted in complete or partial healing in 86.6% of cases.ConclusionClinical results after meniscal repair of a radial tear in the PHLM by using the FasT-Fix system were satisfactory.Level of evidenceCase series, Level IV.     

The menisco-femoral ligaments

The menisco-femoral ligaments were studied in 60 knees from 30 dissecting room cadavers. The anterior horns of the menisci were attached to the intercondylar area of the femur by discrete antero-medial or antero-lateral menisco-femoral ligaments, separate from the anterior cruciate ligament, in 15% of knees for each meniscus, more frequently than previously appreciated; these anterior horn ligaments may exacerbate a meniscal tear. The posterior horn of the lateral meniscus was connected with the intercondylar area of the femur in 100% of knees. In 93% of knees a ligament ran behind the posterior cruciate ligament while in 33% of knees a ligament ran in front of the posterior eruciate ligament. We propose renaming these the pre-cruciate postero-lateral menisco-femoral ligament and post-cruciate postero-lateral menisco-femoral ligament, respectively, to avoid confusion with the ligaments of the anterior horns. The menisco-femoral ligaments may function in controlling movement of the menisci, especially during rotation of the knee. The posterior horn of the medial meniscus has no direct femoral attachment and this may be a factor in the increased risk of injury to this meniscus. © 1995 WiIey-Liss, Inc.     

Deep flexion helps to avoid popliteal artery injury during all-inside lateral meniscal repair: A cadaveric study

BackgroundArthroscopic meniscus repair rarely leads to major complications such as popliteal artery injury. The distance between the suturing device and the popliteal artery, and the risk of popliteal artery injury at different knee flexion angles during all-inside lateral meniscal repair remain unclear.MethodsAll-inside devices were inserted into 10 human cadaveric knees at the posterior horn of the lateral meniscus through the anterolateral portal at 60°, 90°, and 120° knee flexion; posterior segment of the lateral meniscus through the anterolateral portal at 60°, 90°, and 120°; and anteromedial portal at 90°. Distance and positional relationship between the device and popliteal artery were measured radiographically.ResultsIn posterior horn repair through the anterolateral portal, the median distance increased from 5.7 mm at 60° to 9.1 mm at 90° (P = 0.63) and 18.0 mm at 120° (P = 0.02). The device pushed the wire at 60° in three cases, 90° in one case, and 120° in 0 cases. In posterior segment repair through the anterolateral portal, the median distance was 12.6 mm at 60°, 10.4 mm at 90°, and 18.3 mm at 120° (P = 0.08). The median distance at 90° was 18.1 mm through the anteromedial portal, the same as that at 120° through the anterolateral portal (P = 0.43), but greater than that at 90° through the anterolateral portal (P = 0.04). The wire was not pushed in any case.ConclusionAlthough all-inside repair of the posterior part of the lateral meniscus through the anterolateral portal is risky, deeper knee flexion reduces the risk of popliteal artery injury.     

Popliteus muscle in man

This paper describes the morphology of the popliteus muscle based on the dissection of 15 human cadaver's knees. The muscle is found to have three origins: the strongest from the lateral femoral condyle is already wellknown, but there is also an important band from the fibula and a firm attachment to the posterior horn of the lateral meniscus. The femoral and fibular origins form the arms of an oblique Y-shaped ligament, the base of which is formed by the capsule and the meniscal origins. This previously was described as a separate entity, the “arcuate ligament,” attached to the belly of the muscle, but it is not a separate ligament. Rather it is a condensation of the fibers of origin of the popliteus including those from the fibula.