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     

Entrapment of the medial meniscus in a fracture of the tibial eminence

Fracture of the intercondylar eminence of the tibia is unusual in adults. Long-term morbidity is uncommon. This is a case in which the anterior horn of the medial meniscus became entrapped in the fracture site after non-operative treatment of a completely displaced fracture, causing persistent medial knee pain. Arthroscopic release of the entrapped meniscus provided excellent relief of symptoms.     

射频汽化仪在膝关节镜手术中的应用

目的探讨射频汽化仪在膝关节镜手术中的应用及其疗效。方法利用射频汽化仪对78例不同膝关节疾病患者进行关节镜手术,其中半月板部分切除18例,全切除7例,盘状半月板成形13例,损伤软骨及韧带修整21例,滑膜切除6例,髌骨外侧支持带松解5例,胫骨髁间隆突骨折固定6例,前交叉韧带重建2例。结果术后患侧膝关节肿胀轻,未见明显关节积液、积血。随访3～12个月,75例患者自觉症状良好,关节绞锁、疼痛等症状缓解;3例重度骨性关节炎者症状无缓解,转行人工关节置换术。膝关节功能评定：优46例,良29例,可0例,差3例,优良率96．2％。结论射频汽化仪具有良好的低温切除、止血作用,使用方便,有助于提高膝关节镜手术的效率及疗效。     

Meniscectomy

To review the meniscus from a historical perspective especially on surgical management and general guidelines for arthroscopic meniscectomy procedures for various types of meniscal tears. We searched MEDLINE and PubMed for the years of 1980-2010 using the terms meniscus, meniscal repair, menisectomy, and arthroscopy. Orthopedic surgeons frequently encounter patients with pain or functional impairment of the knee joint and repair or resection of the injured meniscus is one of the most common orthopedic operative procedures. The object of meniscal surgery is to reduce pain, restore functional meniscus and prevent the development of degenerative osteoarthritis in the involved knee. Historically, total meniscectomy was a common procedure performed for meniscus tear symptoms. However, it has been reported that total meniscectomy has deleterious effects on the knee. In the past, the menisci were thought as a functionless remnant tissue. Currently, it is known that the meniscus is an important structure for knee joint function. Menisci provide several vital functions including mechanical support, localized pressure distribution, and lubrication to the knee joint. It is widely accepted that the function of the meniscus can be preserved through minimal excision. An arthroscopic partial meniscectomy preserving more of the meniscus is preferred over total meniscectomy. In recent decades, this shift toward arthroscopic partial meniscectomy has led to the development of new surgical techniques.     

Osteonecrosis of the knee after arthroscopic surgery for meniscal tears and chondral lesions.

PURPOSE: Avascular necrosis of the knee following arthroscopic surgery has been described. The purpose of this article is to report a large series of patients who developed avascular necrosis after arthroscopy of the knee in an effort to delineate casual factors and results of treatment. TYPE OF STUDY: Case series. METHODS AND MATERIALS: The charts, radiographs, and magnetic resonance imaging (MRI) scans of patients who developed osteonecrosis (ON) of the knee after routine arthroscopic surgery were reviewed. Only those patients with no evidence of ON on preoperative MRI performed 6 weeks or longer after symptom onset and who postoperatively developed ON confirmed by repeat MRI and/or by pathological testing (specimens obtained at subsequent total knee arthroplasty) were included in the study. Seven patients with average age of 60 years (range, 41 to 79 years) met these inclusion criteria. RESULTS: The lesions noted at arthroscopy included 4 medial meniscus tears, 3 lateral meniscal tears, 6 chondromalacia of the medial femoral condyle, 2 chondromalacia of the medial tibial plateau, 1 chondromalacia of the lateral femoral condyle, 1 chondromalacia of the lateral tibial plateau, and 2 chondromalacia of the patella. The location of postarthroscopy ON correlated geographically with pre-existing pathology. All 7 patients had meniscal and/or chondral lesions addressed surgically in the compartment that subsequently developed ON. Six of the 7 patients had an adjacent ipsilateral meniscus tear treated with partial meniscectomy (4 medial, 2 lateral). In addition, of the 4 patients who developed ON of the medial femoral condyle, all had overlying chondromalacia, 3 of whom were treated with arthroscopic chondroplasty. Of the 2 patients with lateral meniscal tears, 1 developed ON of the lateral femoral condyle and the other developed ON of the lateral tibial plateau. Three patients went on to require total knee arthroplasty, and 2 high tibial osteotomy. One patient's ON resolved and another patient was lost to follow-up. CONCLUSION: ON should be considered in patients who have worsening symptoms after arthroscopy of the knee. These findings suggest a possible relationship between arthroscopic treatment of chondral and meniscal lesions and later appearance of ON in some patients. The role of arthroscopy in the development of ON needs to be further studied. Those at risk are elderly patients with chondral and meniscus lesions.     

Importance of the medial meniscus in the anterior cruciate ligament-deficient knee.

The incidence of meniscal tears in the chronically anterior cruciate ligament-deficient knee is increased, particularly in the medial meniscus because it performs an important function in limiting knee motion. We evaluated the role of the medial meniscus in stabilizing the anterior cruciate ligament-deficient knee and hypothesized that the resultant force in the meniscus is significantly elevated in the anterior cruciate ligament-deficient knee. To test this hypothesis, we employed a robotic/universal force-moment sensor testing system to determine the increase in the resultant force in the human medial meniscus in response to an anterior tibial load following transection of the anterior cruciate ligament. We also measured changes in the kinematics of the knee in multiple degrees of freedom following medial meniscectomy in the anterior cruciate ligament-deficient knee. In response to a 134-N anterior tibial load, the resultant force in the medial meniscus of the anterior cruciate ligament-deficient knee increased significantly compared with that in the meniscus of the intact knee; it increased by a minimum of 10.1 N (52%) at full knee extension to a maximum of 50.2 N (197%) at 60 degrees of flexion. Medial meniscectomy in the anterior cruciate ligament-deficient knee also caused a significant increase in anterior tibial translation in response to the anterior tibial load, ranging from an increase of 2.2 mm at full knee extension to 5.8 mm at 60 degrees of flexion. Conversely, coupled internal tibial rotation in response to the load decreased significantly, ranging from a decrease of 2.5 degrees at 15 degrees of knee flexion to 4.7 degrees at 60 degrees of flexion. Our data confirm the hypothesis that the resultant force in the medial meniscus is significantly greater in the anterior cruciate ligament-deficient knee than in the intact knee when the knee is subjected to anterior tibial loads. This indicates that the demand on the medial meniscus in resisting anterior tibial loads is increased in the anterior cruciate ligament-deficient knee compared with in the intact knee, suggesting a mechanism for the increased incidence of medial meniscal tears observed in chronically anterior cruciate ligament-deficient patients. The large changes in kinematics due to medial meniscectomy in the anterior cruciate ligament-deficient knee confirm the important role of the medial meniscus in controlling knee stability. These findings suggest that the reduction of resultant force in the meniscus may be a further motive for reconstructing the anterior cruciate ligament, with the goal of preserving meniscal integrity.     

Anterograde arthroscopic fixation of avulsion fractures of the tibial eminence with a cannulated screw

Purpose: Fractures of the tibial eminence can be treated arthroscopically. Fixation of the fracture is usually followed by temporary immobilization. The literature suggests that only anterograde fixation with cannulated screws and washer is considered stable enough to allow for immediate mobilization and weight bearing. The goal of this study was to evaluate the 5-year results of arthroscopic reductions and anterograde fixations of the tibial eminence fracture with cannulated screws. Type of Study: Retrospective study. Methods: Thirty-two patients were treated arthroscopically for type II, III, and IV fractures of the intercondylar eminence of the tibia. The fragments were reduced and fixed with a cannulated screw or cannulated screw and washer. The intermeniscal ligament was involved in the fracture in 29 cases, and the anterior part of the medial meniscus was involved in 3 cases, requiring a temporary shift before reduction of the fragment. Arthrotomy was not performed for reduction or fixation of the fragment. All patients began continuous passive and active motion of the involved knee and were mobilized on crutches the day after the procedure. They were allowed immediate weight bearing. The patients were followed up for 16 to 69 months. Results: Good therapeutic results were found at follow-up. Average value for KT-1000 testing was 1.1 mm; flexion deficit was 1.2°; extension deficit, 0.6°; and Lysholm score, 98.8. The average treatment duration was 12 weeks. There was one case of aseptic synovitis and no other complications. In all but 1 patient, the implants were removed. Conclusions: Arthroscopic fixation of the fracture of the intercondylar eminence of the tibia with a cannulated screw or screw and washer is a simple, safe, reproducible, and effective procedure. The fixation is stable even in type IV fractures, so that immobilization is unnecessary.     

Symptomatic Complete Discoid Medial Meniscus Completely Coalesced with the Anterior Cruciate Ligament: A Case Report and Literature Review

BackgroundComplete discoid medial meniscus is an extremely rare abnormality of the knee joint whose meniscus has a discoid shape rather than a normal semilunar one. Several medial meniscus anomalies including anomalous insertion have been reported in the literature. This report presents a rare case of symptomatic complete discoid medial meniscus whose anterolateral (apical) portion was completely coalesced with the ACL. MRI, radiographic, and arthroscopic findings in the medial compartment are to be submitted.Case PresentationA 29‐year‐old male presented with intermittent pain and swelling of the right knee for 2 years. Based on radiographic, MRI, and physical examination findings, he was diagnosed with discoid medial meniscus tears. Arthroscopic saucerization was performed for the torn discoid medial meniscus of the right knee. Arthroscopic examination revealed a complete discoid medial meniscus and the anterolateral (apical) portion of which was completely coalesced with the ACL. Careful Probing of the meniscal surface revealed there was a longitudinal tear extending from the tibial spine to the midportion of the meniscus. Arthroscopic saucerization of the discoid meniscus was performed after closely cutting the meniscus around the ACL. The patient reported no symptoms, and he had returned to his daily and sports activities, including football, basketball, and jogging, at the 12‐month follow‐up.ConclusionComplete discoid medial meniscus is an extremely rare abnormality, and this case presents the third complete discoid medial meniscus whose anterolateral (apical) portion was completely coalesced with the ACL. The current case we present strongly supports the hypothesis that ACL and meniscus were differentiated from the same mesenchyme.     

The anatomy of tibial eminence fractures: arthroscopic observations following failed closed reduction

BACKGROUND: Failed manipulative reduction of avulsion fractures of the tibial insertion of the anterior cruciate ligament has been attributed to interposition of soft tissues, particularly the anterior horn of the medial meniscus. The objectives of the present report were (1) to show that the failure to reduce Meyers and McKeever type-III tibial eminence fractures was not due to interposition of soft tissues and (2) to discuss the relevance of the finding that the anterior third of the lateral meniscus was attached to the avulsed anterior cruciate ligament insertion site in all patients studied. METHODS: Twelve patients who had had a failed manipulative reduction of a type-III tibial eminence fracture underwent arthroscopic reduction and fixation of the avulsed fragment. RESULTS: A number of consistent findings were noted. The avulsed intercondylar eminence was displaced superiorly into the intercondylar notch. Attached to this fragment was not only the anterior cruciate ligament, but also, in all cases, the anterior horn of the lateral meniscus. The anterior third of the lateral meniscus had been torn from its tibial attachment and displaced together with the osseous fragment into the intercondylar notch. No interposition of bone or soft tissue was observed. Reduction of the osseous fragment was facilitated by traction on, or sutures passed around, the anterior horn of the lateral meniscus. Standard fixation methods were utilized. CONCLUSIONS: The concept that avulsion fractures of the tibial insertion of the anterior cruciate ligament cannot be reduced by manipulation because of soft-tissue interposition was not supported by the findings of the present study. The attachment of the anterior horn of the lateral meniscus to the avulsed tibial insertion of the anterior cruciate ligament may not be an irrelevant incidental finding. The observation that the displaced osseous fragment was attached simultaneously to the anterior cruciate ligament and to the anterior horn of the lateral meniscus, both pulling in different directions, may explain why type-III tibial eminence fractures are irreducible by manipulation.     

关节镜下缝线捆扎配合门型钉治疗胫骨髁间嵴骨折

目的探讨关节镜下缝线捆扎配合门型钉治疗胫骨髁间嵴骨折的手术效果。方法采用关节镜下缝线捆扎配合门型钉治疗27例胫骨髁间嵴骨折患者。术后3个月采用Lysholm膝关节功能评分评价疗效。结果患者均获得随访,时间4~38个月。术后3个月内骨折均一期愈合。术后3个月根据Lysholm膝关节功能评分评价疗效:优20例,良5例,可2例,优良率25/27。1例轻度屈膝受限,1例Lachman试验弱阳性。结论关节镜下缝线捆扎配合门型钉治疗胫骨髁间嵴骨折可同时处理其他关节损伤,能较大限度恢复关节功能,是一种安全、简单、有效的手术方法。     

Arthroscopic evaluation after surgical repair of intercondylar eminence fractures

Introduction Patients who undergo surgical repair of intercondylar eminence fracture may have postoperative problems despite good reduction. We used arthroscopy to evaluate the outcomes after surgery to repair intercondylar eminence fractures. Materials and methods Ten patients (8 men and 2 women; average age at the time of surgery 27.9 ± 10.0 years, range from 14 to 50 years) with fracture of the tibial intercondylar eminence underwent an arthroscopic reduction and internal fixation with non-absorbable sutures. Preoperative radiological examination showed that there were one Meyer’s type-II, eight type-IIIA and one type-IIIB fractures. Clinical symptoms and physical findings for all the patients were evaluated 1 year postoperatively. Radiographic assessment and the Lysholm rating scale were also utilized. Second-look arthroscopy was performed after 1 year when removing the implant. Arthroscopy was used to assess the appearance of the surface of the anterior cruciate ligament (ACL), check for the existence of cyclops and look for interposition of tissue in the lateral and medial joint spaces. Results One year after the surgery, all ten patients achieved bony union and had negative Lachman and anterior drawer tests. The average Lysholm knee score was 94.5 ± 7.2 points (range 100–75 points). Arthroscopy showed an irregular surface on the ACL in two of the ten patients, cyclops in two patients, interposition in the lateral joint space in two patients and interposition in the medial joint space in one patient. In the two cases seen with an irregular surface, the ACL was covered with droopy fibrous tissue, but the substance of the ACL was intact. The two patients who had cyclops showed loss of knee extension (5°∼10°), which was regained by subsequent resection of the cyclops. One patient who had an interposition into the lateral joint space complained of catching, which was released by resection of the interposing tissue. Conclusion Arthroscopic refixation of the intercondylar eminence fracture provided bony union and a good clinical outcome. Cyclops syndrome is one of the causes of loss of knee extension, and soft tissue in the medial or lateral compartment is one of the causes of catching of knee after surgical repair of intercondylar eminence fracture. Cyclops syndrome, which may occur following ACL reconstruction, is one of the causes of loss of knee extension after surgical repair of intercondylar eminence fracture. In patients who have knee complaints, such as catching and loss of knee extension, a second-look arthroscopy is useful for identifying and correcting the problem.     

Extension block secondary to partial anterior cruciate ligament tear on the femoral attachment of the posterolateral bundle

Purpose: The purpose of this investigation was to prove that a partial tear of the anterior cruciate ligament (ACL) at the femoral attachment of the posterolateral bundle can result in mechanical knee locking and trigger the injury mechanism of an isolated ACL injury. Type of Study: Case series. Methods: From February 1993 through June 1999, 19 cases of knee locking with observation of a torn ACL, confirmed under arthroscopy, were investigated. Patients’ ages ranged from 22 to 54 years. The causes of injury were sporting activities in 14 patients (8 skiing, 4 soccer, and 2 badminton); slipping and falling in 2 cases; a pedestrian car accident in 2 cases; and an unknown low-velocity injury in 1 case. Results: On physical examination, each patient indicated that the chief complaint was knee pain; all had a locked knee at 5° to 20° of full extension and 4 cases showed a locked knee at full flexion. Of the 19 cases, Lachman testing was positive in 3. With respect to intra-articular injuries, 3 patients had a tear in the medial meniscus and 1 had a tear in the lateral meniscus. The average time span between arthroscopy examinations was 3 months with a range of 1 to 10 months. Arthroscopic diagnosis and treatment were performed and meniscal tear was ruled out as the cause of locking in all patients. Conclusions: The mechanisms of injury for isolated ACL were knee hyperextension and internal rotation of lower extremity brought on especially by a low-velocity injury. The partial ACL tears were found on the femoral attachment site of the posterolateral bundle. The torn segment of the ACL was interposed between the lateral femoral condyle and the lateral tibial condyle and acted as a mechanical obstruction, giving rise to the locking symptom. In all 19 cases, the torn portion of the ACL was excised under arthroscopy and the locked knees were treated properly.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 3 (March), 2002: pp 227–231     

Torn discoid lateral meniscus treated using partial central meniscectomy and suture of the peripheral tear

We present the cases of 5 patients with a torn discoid lateral meniscus treated using partial central meniscectomy in conjunction with the suture repair of the tear. The patients were 4 boys and 1 girl with a mean age of 15.4 years (range, 11 to 17). Preoperatively, all patients complained of knee pain during daily or sports activities. At the final follow-up evaluation, more than 2 years later, 4 patients’ conditions were graded as excellent and 1 patient’s condition was graded as fair according to Ikeuchi’s grading scale. The average Lysholm score improved from 83.4 points (range, 70–90) to 95.8 points (range, 89–100) postoperatively. In the 3 patients who underwent second-look arthroscopy, complete healing was seen in 2 patients. One patient had severe degenerative changes in the meniscus; the repaired site was not united and required an additional partial meniscectomy along the tear. We believe that with the current advancement in arthroscopic meniscal repair techniques, a partial central meniscectomy in conjunction with the suture repair of the peripheral tear can be effective treatment for patients with a torn complete or incomplete discoid meniscus.     

关节镜下治疗胫骨平台塌陷和髁间棘撕脱骨折

目的　探讨应用关节镜技术在微创条件下治疗胫骨平台塌陷和髁间棘撕脱骨折。方法　在关节镜下治疗胫骨平台塌陷 2例 ,髁间棘撕脱骨折 2例 ,胫骨后侧平台塌陷伴髁间棘撕脱骨折 1例。结果　 5例病人骨折复位满意 ,髁间棘撕脱骨折病例其交叉韧带均恢复其张力。患膝无疼痛及不稳 ,关节活动恢复良好。结论　关节镜的使用为治疗胫骨平台塌陷和髁间棘撕脱骨折提供了一种创伤极小、可准确复位手术新方法     

Articular cartilage lesions in the symptomatic anterior cruciate ligament-deficient knee

Purpose: The goal of the study was to report the prevalence of the lesions of the articular cartilage of the femoral condyles and tibial plateau in patients with a symptomatic anterior cruciate ligament (ACL)-deficient knee undergoing day-case arthroscopy. Type of Study: Case series study. Methods: We studied 378 skeletally mature patients (average age, 27.3 years; range, 16–50 years; 282 men and 84 women), part of a sample of 1,978 patients undergoing a primary knee arthroscopy between January 1986 and August 1993. The articular cartilage lesions were classified according to Outerbridge by a single observer. We assessed the relationship between time of injury and articular cartilage lesions and between meniscal lesions and articular cartilage lesions. Results: A complete ACL tear was found in all 378 knees. Of these, 157 showed at least one lesion of the articular cartilage. The medial femoral condyle (MFC) showed the highest frequency of articular cartilage lesions, especially in the weight-bearing portion. Patients with a bucket-handle tear of the medial meniscus had greater degeneration of the MFC than those with other meniscal tears. A meniscal tear was associated with a greater degree of articular damage. The second most common lesion was a combined lesion of the medial and lateral compartments, followed by isolated lateral compartment lesion. A time-dependent pattern of development of articular cartilage lesions was identified. Conclusions: In patients with more advanced degenerative changes, the time from injury to arthroscopy was significantly longer than in patients with lesser articular surface abnormalities, and the presence of a meniscal tear was associated with a greater degree of articular cartilage damage. Patients with a symptomatic ACL-deficient knee and an associated tear of the medial meniscus are at high risk of having a lesion of the articular surface of the weight bearing area of the knee.     

关节镜下儿童胫骨髁间棘骨折的微创治疗

目的：分析儿童胫骨髁间棘骨折的特点,介绍关节镜辅助下微创治疗的方法。方法：对2004年1月至2008年12月12例儿童胫骨髁间棘骨折进行回顾性分析。按照Meyers-McKeever骨折分型：Ⅰ型1例,Ⅱ型4例,Ⅲ型7例。新鲜骨折10例,陈旧骨折2例;男10例,女2例;年龄8～13岁,平均10岁。所有病例进行了关节镜探查、复位,克氏针固定。随访时间10～36个月,了解骨折愈合、关节活动度、膝关节稳定性等情况。合并半月板损伤1例,滑车区软骨损伤1例,半月板嵌入骨块下5例。结果：骨折愈合时间平均5周,无畸形愈合、骨不连,无髁间窝撞击表现。术后3个月Lysholm膝关节功能评分平均（92.7±2.5）分,术后6个月平均（96.4±1.7）分,所有患膝恢复健侧活动度。结论：儿童胫骨髁间棘骨折以Ⅱ、Ⅲ型多见,软骨及半月板等关节內合并伤少见。关节镜辅助下交叉克氏针固定法操作简便、手术创伤小、恢复快,符合儿童骨生长快的特点。     

The accuracy of joint line tenderness by physical examination in the diagnosis of meniscal tears

Purpose: The purpose of this study was to document the accuracy of joint line tenderness in the diagnosis of meniscal tears. Type of Study: Prospective cohort study. Methods: There were 104 male recruits (age range, 18 to 20 years; mean, 19.2 years) with suspected meniscal lesions who underwent arthroscopy. A thorough history and physical examination was performed on each patient by a physician with 4 years’ experience on arthroscopic knee surgery. Twenty-six (25%) patients sustained injuries while in the Turkish Army, and 78 patients (75%) sustained injuries before they came to the army. On physical examination, assessment of joint line tenderness at the lateral and medial joint lines was performed with the patient’s knee flexed 90°. The accuracy, sensitivity, specificity, and positive and negative predictive values of joint line tenderness for medial and lateral sides were calculated based on arthroscopic findings. Results: In 104 knees, the diagnosis was correct in 71 (68%) and incorrect in 33 (32%) knees. A total of 37 medial meniscal tears and 27 lateral meniscal tears were identified at arthroscopy. Other pathology included 11 anterior cruciate ligament (ACL) tears, 5 medial femoral chondral lesions, 4 chondromalacia patellae, and 1 medial plica. No discernable abnormalities were seen in 21 knees. A preoperative diagnosis of a medial meniscal tear was made in 54 knees and 32 were confirmed at arthroscopy. A lateral meniscus tear was suspected in 27 knees and confirmed in 25. Five medial meniscus and 2 lateral meniscus tears were seen at arthroscopy. These had not been suspected with tenderness over the joint line. The accuracy of the test was lower with the presence of ACL lesions and condromalacia patella. Conclusions: I concluded that joint line tenderness as a test for lateral meniscal tears is accurate (96%), sensitive (89%), and specific (97%). However, for medial meniscal tears, rates are lower.     

Arthroscopic partial meniscectomy of a posteriorly flipped superior leaflet in a horizontal medial meniscus tear using a posterior transseptal portal

This article describes a case of an arthroscopic partial meniscectomy of a posteriorly flipped superior leaflet in a horizontal medial meniscus tear using the posterior transseptal portal. An arthroscopic partial meniscectomy for bucket handle or flap tears in medial or lateral compartments using ordinary portals is a relatively common procedure in irreparable cases. However, the posterior compartment of the knee is not readily accessible through ordinary arthroscopic portals. Therefore, it has been considered a blind spot. Through the posterior transseptal portal, surgeons can achieve excellent arthroscopic visualization of the posterior compartment and easily perform arthroscopic procedures of the posterior compartment of the knee. A 48-year-old woman presented with a 1-year history of pain in the medial aspect of the right knee joint. Preoperative magnetic resonance imaging revealed a thinning of the medial meniscus posterior horn in coronal images and a sharp-edged triangle arising from the medial meniscus posterior horn between the medial femoral condyle and medial meniscus posterior horn on sagittal images (flipped-over sign). During the arthroscopic procedure, we found that the flipped leaflet was displaced posteriorly and was not mobile between the medial femoral condyle and medial meniscus posterior horn. Partial meniscectomy for a posteriorly displaced fragment can be performed successfully using the posterior transseptal portal. The posterior transseptal portal is useful for an arthroscopic partial meniscectomy of a posteriorly flipped leaflet in the posterior compartment of the knee.     

Incarceration of the meniscus in fractures of the intercondylar eminence of the tibia in children

Four cases of trapping of the meniscus in type II or III fractures of the intercondylar eminence of the tibia in children are reported. At operation the fragments could not be apposed until the meniscus had been lifted out of the fracture. In our opinion, if they had not been operated on these patients would have had persistent trouble in the knee, including non-union, loss of extension and laxity of the anterior cruciate ligament. We therefore recommend either operation for type II and type III lesions or arthroscopy. If the meniscus is trapped we suggest that it should be lifted out and the fragments apposed under arthroscopic control.     

Bilateral Discoid Medial Menisci

Summary: This article adds 2 more cases of bilateral discoid medial menisci to the previously reported 9 cases. The radiographs of the first case revealed bilateral cupping of the medial tibial plateaus and a small lytic lesion of the left distal medial femoral metaphysis. Beside the posteriorly unstable incomplete type discoid medial meniscus, the left knee had several associated arthroscopic findings: depression of the medial tibial plateau with exposed subchondral bone, anomalous insertion of the anterior horn of the discoid meniscus to the anterior cruciate ligament, a pathological medial plica, and longitudinal deep fissures in the trochlea. The second case was a complete type with peripheral horizontal cleavage tears. Following arthroscopic surgery, magnetic resonance imaging (MRI) scans of the contralateral knees were obtained in both cases to search for bilaterality. MRI revealed discoid medial menisci in the unoperated knees as well. The short-term results of arthroscopic meniscectomy may not be as satisfactory as those reported for normal menisci.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 1 (January-February), 2000: pp 96–101