Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation

A female student had a complete discoid medial meniscus of right knee combined with a meniscal cyst and anomalous insertion to the anterior cruciate ligament. This was confirmed by magnetic resonance imaging (MRI) and the arthroscopic procedure. Also shown by the MRI, the left knee had the discoid medial meniscus, but it was asymptomatic.     

Arthroscopic one-piece reshaping for symptomatic discoid medial meniscus with anomalous amalgamating into anterior cruciate ligament

Discoid shapes of lateral menisci are relatively common finding, whereas discoid medial menisci are less common. Discoid medial meniscus with associated anomalous variants has been reported. However, symptomatic complex tear of complete type discoid medial meniscus with anomalous blending with anterior cruciate ligament is an extremely rare pathology. A 35-year-old male was admitted to our hospital with left knee pain and loss of terminal extension for 2 years. On physical examination, the patient presented with clicking and restriction during the extension motion of the knee joint. Magnetic resonance imaging and arthroscopy indicated complex tear of complete discoid medial meniscus in association with anomalous connection between entire apical portion of discoid medial meniscus and tibial insertion portion of the anterior cruciate ligament. We obtained a successful outcome with arthroscopic resection and shaping in one-piece method using no. 11 scalpel blade.     

Locked knee caused by meniscal subluxation: magnetic resonance imaging and arthroscopic verification

Subluxation or dislocation of an intact lateral meniscus is a controversial and rarely reported cause of knee pain and locking. We report a case of knee locking caused by lateral meniscal subluxation in the absence of a meniscal tear or true discoid meniscus, with both magnetic resonance imaging (MRI) and arthroscopic verification. A 9.5-year-old child experienced multiple episodes of locking in full flexion of the knee. After 6 months of symptoms, arthroscopy was performed and showed no meniscal tear or a discoid meniscus. The patient’s knee locking recurred after arthroscopy. MRI was performed when the patient presented acutely with the knee locked. MRI showed anterior dislocation of the posterior horn of the lateral meniscus with the knee in the locked position. The MRI was immediately repeated after the author reduced (manipulated) the locked knee into extension. On the repeat MRI, the lateral meniscus had returned to a normal position. On repeat arthroscopy, the posterior horn of the lateral meniscus was hypermobile and could be displaced into the notch and did not show a frank tear. The meniscus was repaired to the capsule with sutures. At the 2-year follow-up evaluation, the patient had no complaints and no clinical signs of locking.     

Diagnostic value of clinical tests and Mri for meniscal injury in patients with anterior cruciate ligament injury: Case series study

Introduction and importanceMeniscal tear is one of the most common knee injuries and knee surgery procedures. It is frequently associated with an anterior cruciate ligament (ACL) injury. We conducted this study, on patients with ACL reconstruction surgeries, which were occasionally accompanied by meniscal tears, in order to determine the diagnostic value of clinical examinations for meniscal tear, both individually and in combination, in correlations to magnetic resonance imaging (MRI) scans, with the goal of improving clinical diagnosis for patients with meniscal injuries in particular, as well as meniscal injuries associated with cruciate ligament knee injuries.Case presentation50 patients were thoroughly clinically examined, using Joint line tenderness, Thessaly test, McMurray's test, Apley's test followed by MRI, before their scheduled ACL reconstruction arthroscopic surgeries. The meniscal tears were then identified during the procedure, and were treated, if necessary. The data before and after the surgery was taken into calculating, with arthroscopic findings serving as the gold standard. Results: the sensitivity, specificity and accuracy of each clinical tests and MRI scans respectively were: for medial meniscus, Joint line tenderness (70%; 53,3%; 60%); McMurray's test (80%; 73,3%: 76%); Apley's test (65%; 70%; 68%); Thessaly test(70%; 76,7%; 74%); MRI (90%; 83,3%; 86%); lateral meniscus: Joint line tenderness (73%; 66,7%; 70%); McMurray's test (69,2%; 75%: 72%); Apley's test (69,2%; 70,8%; 70%); Thessaly test (73,1%; 75%; 74%); MRI (88,5%; 87,5%; 88%). However, when combining at least two positive tests into a single composite test, the diagnostic value is considerably enhanced with sensitivity, specificity and accuracy of 85%, 73,3%, 78% for medial meniscus, 92,3%, 87,5%, 90% for lateral meniscus.Clinical discussionClinical tests are essential for diagnosis of meniscal tears, although inconsistent. A composite test consisting of at least two positive tests can considerably enhance the diagnostic value, even comparable to MRI scans. However, after the clinical examination, MRI is still necessary for the diagnostic process of meniscal injuries in particular, as well as meniscal injuries associated with cruciate ligament knee injuries.ConclusionThe combination of clinical tests and MRI images will give a precise diagnosis as well as surgical indication for meniscus injury in patients with anterior cruciate ligament tear.     

Common pitfalls in magnetic resonance imaging of the knee

Magnetic resonance examinations of 200 knees were studied retrospectively to determine the frequency with which normal ligamentous and tendinous structures mimicked pathological changes in the meniscus or elsewhere in the knee. Although the course of the transverse geniculate ligament simulated a tear of the anterior horn of the lateral meniscus on forty-four (22 per cent) of the sagittal magnetic-resonance scans, no tear of the lateral meniscus was found in the nine patients in this group who had an arthroscopic examination. The normal anatomy of the meniscofemoral ligament varies greatly. The ligament of Humphry, the anterior branch of the meniscofemoral ligament, was visualized on sixty-six (33 per cent) of the magnetic resonance scans. The ligament of Wrisberg, the posterior branch of the meniscofemoral ligament, was identified on sixty-five (32.5 per cent) of the scans. On sagittal images, these ligamentous branches can be mistaken for osteochondral or meniscal fragments. However, a loose body was found in only one of the thirty-two patients who had an arthroscopic examination after the ligament of Humphry or of Wrisberg was seen on the magnetic resonance image. The bursa of the popliteus tendon simulated a tear of the posterior horn of the lateral meniscus in fifty-five (27.5 per cent) of the studies, although an actual tear of the posterior horn was found in only two of the eleven patients who had an arthroscopic examination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical,MRI, and arthroscopic correlation in meniscal and anterior cruciate ligament injuries

The aim of this prospective study was to compare and correlate clinical, magnetic resonance imaging (MRI), and arthroscopic findings in cases of meniscal tear and anterior cruciate ligament (ACL) injuries. MRI scan results and clinical diagnosis are compared against the arthroscopic confirmation of the diagnosis. One hundred and thirty-one patients had suspected traumatic meniscal or anterior cruciate ligament (ACL) injury. Clinical examination had better sensitivity (0.86 vs. 0.76), specificity (0.73 vs. 0.52), predictive values, and diagnostic accuracy in comparison to MRI scan in diagnosis for medial meniscal tears. These parameters showed only marginal difference in lateral meniscal and anterior cruciate ligament injuries. We conclude that carefully performed clinical examination can give equal or better diagnosis of meniscal and ACL injuries in comparison to MRI scan. MRI may be used to rule out such injuries rather than to diagnose them.     

Discoid lateral meniscus in children: limited knee extension and meniscal instability in the posterior segment

BACKGROUND: Limited knee extension is a well-known sign in children with discoid meniscus, but its causative mechanism is controversial. The purpose of this study was to characterize discoid meniscus with this clinical manifestation with a focus on instability of the posterior segment and its morphologic features. METHODS: The authors retrospectively reviewed magnetic resonance imaging and intraoperative arthroscopic videos of 34 knees in 32 consecutive patients (age range, 4.5-15.0 years) who underwent arthroscopic treatment for symptomatic discoid lateral meniscus. Knees were classified into 2 groups, depending on the presence (n = 19) or absence (n = 15) of an extension block, which was defined as a limitation of knee extension by 10 degrees or more under general anesthesia. Meniscal instability in the posterior segment was determined based on arthroscopic findings, and its correlation with knee extension block was analyzed. Using magnetic resonance imaging, the thicknesses of anterior and posterior segments were measured to assess significance of the thickness differences by a presence of knee extension block and by the posterior segment instability. RESULTS: There were 13 knees with a stable posterior segment and 21 knees with an unstable posterior segment. Meniscal instability in the posterior segment was observed in the knees with a surface tear (n = 12), in a hypermobile posterior rim despite the absence of a surface tear (n = 5), and in knees with a freely movable posterior rim without posterior tibial attachment (n = 4). Knee extension block occurred exclusively in complete type menisci and was significantly correlated with meniscal instability in the posterior segment. Magnetic resonance imaging observations suggested that morphologic features characteristic of thick anterior and thin posterior segments were significantly associated with meniscal instability in the posterior segment. Clinically, knee extension block disappeared in all cases within 4 months of arthroscopic treatment. CONCLUSIONS: A redundant anterior segment associated with meniscal instability in the posterior segment is likely to cause limited knee extension in children with discoid lateral meniscus. This correlation mandates that discoid menisci be thoroughly evaluated during arthroscopic treatment to identify any instability that might require stabilization.     

Accuracy of diagnoses from magnetic resonance imaging of the knee. A multi-center analysis of one thousand and fourteen patients

Magnetic resonance images of the knee were made for 1014 patients, and the diagnosis was subsequently confirmed arthroscopically. The accuracy of the diagnoses from the imaging was 89 per cent for the medial meniscus, 88 per cent for the lateral meniscus, 93 per cent for the anterior cruciate ligament, and 99 per cent for the posterior cruciate ligament. The magnetic resonance examinations were done at several centers, and the results varied substantially among centers. The accuracy ranged from 64 to 95 per cent for the medial meniscus, from 83 to 94 per cent for the lateral meniscus, and from 78 to 97 per cent for the anterior cruciate ligament. The results from different magnetic-resonance units were also compared, and the findings suggested increased accuracy for the units that had a stronger magnetic field. Of the menisci for which the magnetic resonance signal was reported to be Grade II (a linear intrameniscal signal not extending to the superior or inferior meniscal surface), 17 per cent were found to be torn at arthroscopy.     

Both medial and lateral bucket-handle meniscus tears associated with chronic ACL injury: A rare presentation of triple-PCL sign

BackgroundSeveral types of meniscal tear could be presented in both acute and chronic anterior cruciate ligament injury. The incidence of bucket-handle meniscus tears can be up to 30% of the overall meniscus tears cases. The case of both compartment (medial and lateral) bucket-handle meniscus is rarely occurred.CaseA case of both medial and lateral bucket-handle meniscus tears was reported in a male of 21 years old. The patient also had a chronic anterior cruciate ligament injury. The magnetic resonance imaging also showed a rare presentation of the triple-PCL sign with the sagittal view. Arthroscopic surgery with a meniscus repair and anterior cruciate ligament reconstruction was performed on the patient.ConclusionsSeveral specific imaging signs including triple-PCL sign could be presented in a rare case of both medial and lateral bucket-handle meniscus tears. Recognition of this sign is important to have accurate preoperative diagnosis and proper treatment plan.     

Anomalous insertion of the medial menisci

Many types of meniscal anomalies have been reported. The authors encountered two cases of anomalous insertion of the anterior horn of the medial menisci to the lateral femoral condyle, which ran up along the course of the anterior cruciate ligament (ACL), but was independent of the ACL. These anomalies were noted during arthroscopic examination and surgery of the ipsilateral knee for a torn discoid meniscus and a patellar fracture. A 34-year-old woman had a horizontal tear of the lateral discoid meniscus. We performed arthroscopic partial meniscectomy of the inner torn portion of the lateral discoid meniscus and contoured it to resemble a normal meniscus. An anomalous insertion of the medial meniscus was found on examination of the joint during surgery. A 32-year-old man had a patellar fracture and we performed reduction under arthroscopy and internal fixation with cannulated screws. The same anomalous insertion of the medial meniscus was also found on examination of the joint during surgery. We report the cases with a review of the literature.Arthroscopy 1998 Jul-Aug;14(5):505-7     

Regeneration of ring-shaped lateral meniscus after partial resection of discoid meniscus with anterior cruciate ligament reconstruction

INTRODUCTIONThe ring-shaped lateral meniscus is very rare. Although it is essentially known as a congenital anomaly, a central tear in an incomplete discoid meniscus or an old bucket-handle tear in a meniscus may be easily mistaken for a ring-shaped meniscus. We experienced a ring-shaped lateral meniscus that regenerated after partial resection of a discoid meniscus together with anterior cruciate ligament (ACL) reconstruction.PRESENTATION OF CASEA 37-year-old female patient still experienced unrelenting knee pain 6 months after ACL reconstruction and partial meniscectomy of a discoid lateral meniscus. A repeat arthroscopy was performed. The lateral tibial plateau was covered in the form of a ring by meniscus-like tissue. The meniscus-like tissue appeared to have regenerated inward toward the center from the stump after the partial meniscectomy and was connected from the anterior to posterior horn, forming an interhorn bridge. Partial meniscectomy was repeated. Histologically, the regenerated tissue was not meniscal, but comprised mature fibrocartilage; macroscopically; however, it was very similar to meniscal tissue. Two years after the initial operation, the patient had no complaints and experienced full return of function.DISCUSSIONThe reason for such regeneration is unknown, but may have been attributed to the specific intra-articular environment that developed after the ACL reconstruction.CONCLUSIONThis is the first report of regenerative development of a ring-shaped lateral meniscus. When a ring-shaped lateral meniscus is diagnosed, we must accurately determine whether it is a true congenital anomaly in consideration of the present case.     

Radial Displacement of Lateral Meniscus After Partial Meniscectomy

Radial displacement or extrusion of the meniscus has been reported as a complication after meniscal transplantation and is sometimes observed in knees with advanced osteoarthritis. In this report, the case of a patient with radial displacement of the lateral meniscus after partial meniscectomy is presented. He had an incomplete discoid lateral meniscus with an anterior horn tear. The inner portion of the lateral meniscus was excised to leave a width of 8 to 10 mm. However, follow-up magnetic resonance imaging showed radial displacement of the mid-body of the lateral meniscus and a compatible finding of chondromalacia of the lateral compartment of the knee.     

经胫骨隧道悬吊固定治疗半月板后根部撕脱损伤

目的观察关节镜下经胫骨隧道拉出悬吊固定技术治疗半月板后根部撕脱损伤的临床效果。 方法自2014年9月至2017年12月,对20例前交叉韧带损伤伴随半月板后根部撕脱损伤的患者,在前交叉韧带单束重建的同时采用关节镜下经胫骨隧道拉出悬吊固定技术修复半月板后根部撕脱损伤。纳入前交叉韧带损伤伴随半月板后根部撕脱损伤的患者,排除术前下肢力线异常者及合并软骨损伤者。术前和术后1年时通过Lysholm评分和Tegner评分对患者膝关节功能进行评估,并通过磁共振(MR)观察术后半月板后根部撕脱损伤愈合情况。定量资料比较采用配对样本t检验。 结果所有患者均进行超过1年的随访,患者术后1年随访时Lysholm评分及Tegner评分较术前均有显著提高(t＝7.98、5.55,均为P<0.05);且MR观察未发现半月板后根部再撕裂或半月板体部外凸。 结论关节镜下经胫骨隧道拉出悬吊固定技术可将半月板后根部撕脱复位并稳定固定于其解剖止点区域,从而维持半月板的环状结构以期最大程度恢复膝关节的功能,短期临床效果良好。     

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。     

The accuracy of selective magnetic resonance imaging compared with the findings of arthroscopy of the knee

The results of selective magnetic resonance imaging of the knee were compared with those of arthroscopy in a prospective series of fifty patients. A specifically designed protocol for imaging, producing T1 sagittal images interleaved at four millimeters while the patient's foot was in 20 degrees of external rotation, was utilized. This technique, called selective magnetic resonance imaging, yielded excellent visualization of the posterior cruciate ligament, medial meniscus, and lateral meniscus in all patients. However, in only 76 per cent of the patients was the anterior cruciate ligament well visualized. Compared with arthroscopy, the sensitivity, specificity, and accuracy of selective magnetic resonance imaging were, respectively, 95.8, 100, and 98 per cent for tears of the medial meniscus; 66.7, 95.1, and 90 per cent for tears of the lateral meniscus; undefined, 100, and 100 per cent for tears of the posterior cruciate ligament; and 100, 96.9, and 97.3 per cent for tears of the anterior cruciate ligament, when that ligament was well visualized. Our selective sequence can be performed in fifteen minutes at a cost that is comparable with that of arthrography. It is totally non-invasive and requires no exposure to ionizing radiation. Selective magnetic resonance imaging can be a safe and valuable adjunct to the clinical evaluation of the knee and an aid to efficient preoperative planning.     

Hemarthrosis after trauma to the pediatric knee joint: what is the value of magnetic resonance imaging in the diagnostic algorithm?

In children, compulsory arthroscopy for hemarthrosis after knee trauma is not justified because ligamentous and meniscal damage is rare. In a prospective study, we analyzed the diagnostic value of radiography, magnetic resonance imaging (MRI), and arthroscopy in 51 patients up to 14 years of age with acute knee trauma. Plain radiography revealed 16 osseous lesions (5 metaphyseal, 3 patellar, 4 physeal fractures, 3 avulsions of the tibial spine, and 1 osseous ligamentous tear). In 29 patients, the cause of hemarthrosis remained unclear. All patients were evaluated by MRI. A diagnosis could be assigned to all 29 patients. MRI demonstrated lesions in 38 patients. In addition, the following lesions were discovered: 8 patellar dislocations, 13 bruises, 1 rupture of the anterior cruciate ligament, 1 osteochondritis dissecans, and 13 joint effusions. In 13 patients, MRI was followed by arthroscopy to confirm the diagnosis. Both, MRI and arthroscopy missed two osteochondral fractures. In addition, three chondral lesions were not picked up by MRI. MRI is a reliable tool for assessing the extent of knee lesions in children.     

Eight- to 14-year followup of arthroscopic meniscal repair

The current study aims to elucidate the midterm to long-term progression of arthroscopic meniscal repair which had been confirmed through a second-look arthroscopy at an average of 10 months after repair. Twenty-eight menisci of 28 patients were investigated at 8 to 14 years (mean, 10.2 +/- 1.8 years), eight after isolated meniscal repair (Isolated group) and 20 after concomitant anterior cruciate reconstruction (Anterior cruciate ligament group). All were rated excellent except four that rated good in the anterior cruciate ligament group as indicated by Lysholm's score at followup. None of the Isolated group, but 12 of the Anterior cruciate ligament group, had osteoarthritic changes seen on radiographs. Four and 19, respectively, had increased signal intensity on magnetic resonance imaging scans, 10 in the Anterior cruciate ligament group had changes of Grade 3 severity. However, no meniscal signs or symptoms were present and no significant relationship between findings of radiographs and magnetic resonance imaging scans was apparent. Anterior cruciate reconstructed knees that were changed to Grade 3 severity as seen on magnetic resonance imaging scans had higher sagittal instability seen on stress radiography than knees with Grade 2 or less severe changes. The anterior laxity of the knees influenced the severity of meniscal signal changes on the magnetic resonance imaging scans.     

Medial discoid meniscus completely coalesced with the anterior cruciate ligament

Medial discoid meniscus is an uncommon abnormality. To date, only a few reports have described the associated anomaly with discoid meniscus. However, there are no reports on medial discoid meniscus accompanied by an anomaly of the meniscus itself. The authors found that a medial discoid meniscus completely coalesced with the anterior cruciate ligament. This anomaly strongly supports the congenital development theory of discoid meniscus. Both magnetic resonance imaging and the arthroscopic findings are presented. The patient was treated successfully by saucerization of the discoid meniscus up to the torn edge. This was accomplished by closely cutting the meniscus around the anterior cruciate ligament with an electric cutter.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 7 (September), 2001: E27     

Meniscal tears in children and adolescents: results of operative treatment

The goal of this study was to evaluate the results of meniscal repair in children and adolescents by a retrospective case series. Twelve arthroscopic-assisted meniscal repairs were performed on 12 patients younger than 17 years of age (8-16 years, mean 13 years). The anterior cruciate ligament was torn in three cases. Eight lesions involved the lateral meniscus and four involved the medial meniscus; there were no discoid menisci. All patients were seen at an average of 3 years 1 month follow-up (range, 2-4 years 10 months). Three patients required subsequent surgery for partial meniscectomy. We evaluated the remaining nine patients by clinical examination, International Knee Documentation Committee clinical score, Lysh?lm score, Tegner's activity, and by computed tomography arthrogram or magnetic resonance imaging. Seven patients were asymptomatic at follow-up, two reported occasional pain, and none had experienced symptoms of locking. Their average Lysh?lm score and Tegner's activity were 96.3 and 6.6, respectively. Eight patients were International Knee Documentation Committee A and one was International Knee Documentation Committee B. Healing status was assessed at follow-up in eight patients by computed tomography arthrogram or magnetic resonance imaging: the tear was considered as completely healed in three patients. The apparent failure rate was 66%. Indications for meniscal repair in children are not actually established. The pejorative outcome of meniscectomy at a young age has led us to consider symptomatic meniscal tears for repair. Objective results of meniscal healing are poor. The method to assess healing of the repaired menisci objectively is still a matter of debate.     

Discoid lateral meniscus in children: clinical manifestations and morphology.

The authors investigated the correlation between the clinical manifestations and the morphology of discoid lateral meniscus. Thirty-eight children, age 5 to 17 years, with 39 cases of discoid lateral meniscus underwent an arthroscopic procedure and magnetic resonance imaging. The two most frequent preoperative clinical manifestations were pain and extension block. In 19 cases without surface tear, the most frequent clinical manifestation was extension block. In the sagittal magnetic resonance images, the mean thickness of the anterior portion of the discoid lateral meniscus (7.77 mm) in the group with extension block exceeded that (4.02 mm) in the group without extension block. Extension block was significantly more common in patients with the anterior hypertrophy type and the slab (anterior-posterior diffusely hypertrophic) type than in the posterior hypertrophy type by the modified Hall classification. As a result, extension block was significantly correlated with the morphology of the menisci. Also, the thickened anterior portion of the discoid lateral meniscus may be considered one of the mechanical factors that limit knee extension.