Association of peripheral vertical meniscal tears with anterior cruciate ligament tears

OBJECTIVE: The purpose of this article is to describe a type of meniscal tear seen on magnetic resonance (MR) imaging, the peripheral vertical tear, and to determine the prevalence of anterior cruciate ligament (ACL) tears in knees with this type of meniscal tear compared to knees with other types of meniscal tears. MATERIALS AND METHODS: Following Institutional Review Board approval, a retrospective review of 200 knee MR examinations with imaging diagnoses of 'meniscal tear' was performed to assess the location and morphology of the meniscal tear, and to assess the status of the ACL. RESULTS: Nineteen peripheral vertical meniscal tears were identified in 17 patients, 14 of whom had acute ACL tears, prior ACL reconstruction, or chronic ACL deficiency. Three peripheral vertical tears were seen in the setting of a normal ACL. Of the 183 examinations with other types of meniscal tears, there were 17 cases with acute ACL tears, prior ACL reconstruction, or chronic ACL deficiency. The difference in the prevalence of ACL tear, reconstruction, or deficiency in knees with meniscal tears of the peripheral vertical type (82.4%) compared with the prevalence of ACL tear, reconstruction, or deficiency in knees with other types of meniscal tears (9.3%) was statistically significant (P < 0.001). The calculated specificity of the presence of peripheral vertical tear morphology in detecting an ACL injury in patients with meniscal tears was 98.2%. CONCLUSIONS: Peripheral vertical meniscal tears, particularly when involving the posterior horn, are highly associated with ACL tear, deficiency, or reconstruction. The finding of this type of tear on knee MR imaging should prompt close inspection of the ACL for evidence of acute or chronic injury, and its presence may help make the diagnosis of ACL tear in equivocal cases.     

Healing potential of meniscal tears without repair in knees with anterior cruciate ligament reconstruction

BACKGROUND: Few previous studies have documented the healing potential of meniscal tears that are left to heal without repair. PURPOSE: To determine the healing rates of meniscal tears left without repair in knees with anterior cruciate ligament reconstruction. STUDY DESIGN: Prospective cohort study. METHODS: One hundred and ninety-two knees were evaluated at the time of anterior cruciate ligament reconstruction and repeat arthroscopy. The healing rates of 41 medial and 42 lateral torn menisci without repair were evaluated by the same 2 surgeons in an identical fashion. RESULTS: Of 41 medial torn menisci left without repair, 22 (56%) were considered completely healed, 3 (7%) were incompletely healed, 11 (24%) were unhealed, and 5 (10%) had expanded unhealed lesions. Of 42 lateral torn menisci, 31 (74%) were considered completely healed, 2 (5%) were incompletely healed, 6 (14%) were unhealed, and 3 (7%) had expanded unhealed lesions. The healing rate of a medial meniscal tear was length dependent and not related to reconstructed ligament stability. CONCLUSIONS: Stable meniscal tears at the time of anterior cruciate ligament reconstruction possibly could be left in situ. However, longer medial meniscal tears are thought to require additional stabilizing procedures.     

Anterior cruciate ligament tears and associated meniscal lesions: assessment at dual-detector spiral CT arthrography

PURPOSE: To assess dual-detector spiral computed tomographic (CT) arthrography of the knee in the evaluation of anterior cruciate ligament (ACL) tears and associated meniscal lesions. MATERIALS AND METHODS: ACL and meniscal abnormalities in 125 consecutive patients who underwent dual-detector spiral CT arthrography of the knee were evaluated on the basis of both initial interpretations and retrospective review of CT images and were compared with arthroscopic findings. The sensitivity and specificity of CT arthrography for the detection of ACL tears and meniscal lesions in knees with abnormal ACLs were determined. RESULTS: The sensitivities and specificities for the detection of ACL tears were 90% and 96%, respectively, at initial interpretation and 95% and 99%, respectively, at retrospective interpretation. The sensitivities and specificities for the detection of meniscal tears in knees with abnormal ACLs were 92% and 88%, respectively, at initial interpretation and 96% and 94%, respectively, at retrospective interpretation. CONCLUSION: Dual-detector spiral CT arthrography of the knee is an accurate method for detecting ACL tears and associated meniscal lesions.     

O'Donoghue's triad: magnetic resonance imaging evidence

Objective The objective was to search for magnetic resonance imaging evidence of medial collateral ligament (MCL) injury in knees with proven tears of the anterior cruciate ligament (ACL) and medial meniscus; the three abnormalities that make up O'Donoghue's triad. Although the MCL injury can be unapparent clinically, knee joint stability may be compromised. Design The superficial portion of the MCL was evaluated on 19 MR studies of 16 knees with arthroscopically proven ACL and medial meniscal tears. MCL thicknesses were compared to those on MR images of 19 normal knees. Patients The injured knees were of 13 men and 3 women, ranging in age from 19 to 56 years; the normal knees were of 10 men and 9 women, ranging in age from 19 to 55 years. Results and conclusions The medial collateral ligaments of all injured knees were abnormal, and, as a group, they had greater thicknesses and more intraligamentous thickness variability than normal knees. The MR appearance of both ACL and medial meniscal tears served as indirect evidence of MCL injury, with irregular MCL thickening indicative of prior injury.     

Anomalous insertion of the medial meniscus into the anterior cruciate ligament: the MR appearance

The aim of this study was to determine the characteristic MR findings of the anomalous insertion of the medial meniscus (AIMM) into the anterior cruciate ligament (ACL), and to document potential pitfalls in its interpretation. We reviewed 1326 consecutive knee arthroscopic studies to identify patients with an AIMM. 30 knees of 26 patients (4 females, 22 males; average age, 31.3 years; range, 14-50 years) were included in this study. We evaluated the presence of an AIMM and analysed the MR findings, including the ACL attachment sites of the AIMMs, the absence of the transverse ligament, meniscal tears and a discoid meniscus. AIMMs were detected by MR imaging in 16 knees of 18 patients (60%, 18/30). The AIMMs showed a linear band with low signal intensity on T2 weighted sagittal images running parallel to the ACL. The AIMMs were inserted into the lower portion of the ACL in eight knees, the middle portion in five knees, and the intercondylar notch in five knees. Meniscal tears (10 medial, 10 lateral) were found in 20 knees of 16 patients. Six knees of five patients showed a discoid meniscus. 15 knees of 14 patients showed no transverse ligament on MR imaging. An AIMM has the potential to be misinterpreted as a meniscal tear, ACL tear or infrapatellar plica on knee MR imaging. Familiarity with the characteristic MR findings can aid in the detection of an AIMM into the ACL.     

The deep lateral femoral notch: an indirect sign of a torn anterior cruciate ligament.

Magnetic resonance (MR) imaging has shown that tears of the anterior cruciate ligament (ACL) are frequently accompanied by meniscal and osseous injuries. Abnormalities of the cartilage overlying the lateral femoral condylopatellar sulcus (notch) also have been noted during arthrotomy of ACL-deficient knees. In this study, the appearance of this sulcus on MR images and the depth of the sulcus on conventional radiographs are compared in patients with normal and torn ACLs to determine whether a deep sulcus is a useful indirect sign of a torn ACL. In 62 patients with clinically and/or arthroscopically confirmed normal ACLs, the mean depth of the lateral femoral sulcus was 0.45 mm (range, 0.0-1.2 mm) compared with 0.89 mm (range, 0.0-5.0 mm) in 41 patients with clinically and/or arthroscopically confirmed ACL tears (significant at the 5% level). No patient with a normal ACL had a sulcus greater than 1.2 mm in depth. A sulcus deeper than 1.5 mm is equivalent to 3 standard deviations above the mean and was a reliable indirect sign of a torn ACL.     

Patterns of meniscal injury with acute anterior cruciate ligament tears

One hundred two patients underwent an arthrotomy for the primary repair of an acute ACL tear with or without an associated collateral ligament injury. The mean age was 23 years. Forty-seven patients (46%) had meniscal injuries. Meniscal injuries were found in 41% of Group I patients (isolated ACL injuries) and in 54% of Group II patients (injured ACL/collateral ligaments). Twenty-eight medial and 22 lateral meniscal tears were noted. Twenty-six of the 50 meniscal tears (52%) were sutured in an attempt to repair the menisci. Of these, 20 of the medial (71%), and 6 of the lateral (27%) meniscal injuries were sutured. No patients in this series required a total meniscectomy. A thorough evaluation of the menisci is mandatory in knees with an acutely injured ACL.     

Anterolateral ligament abnormalities in patients with acute anterior cruciate ligament rupture are associated with lateral meniscal and osseous injuries

Objective

To determine the frequency of anterolateral ligament (ALL) injury in patients with acute anterior cruciate ligament (ACL) rupture and to analyse its associated injury patterns.

Methods

Ninety patients with acute ACL rupture for which MRI was obtained within 8 weeks after the initial trauma were retrospectively identified. Two radiologists assessed the status of the ALL on MRI by consensus. The presence or absence of an ALL abnormality was compared with the existence of medial and lateral meniscal tears diagnosed during arthroscopy. Associated collateral ligament and osseous injuries were documented with MRI.

Results

Forty-one of 90 knees (46 %) demonstrated ALL abnormalities on MRI. Of 49 knees with intact ALL, 15 (31 %) had a torn lateral meniscus as compared to 25 torn lateral menisci in 41 knees (61 %) with abnormal ALL (p?=?0.008). Collateral ligament (p?≤?0.05) and osseous injuries (p?=?0.0037) were more frequent and severe in ALL-injured as compared with ALL-intact knees.

Conclusion

ALL injuries are fairly common in patients with acute ACL rupture and are statistically significantly associated with lateral meniscal, collateral ligament and osseous injuries.

Key Points

? ALL injuries are fairly common in patients with acute ACL rupture. ? ALL injuries are highly associated with lateral meniscal and osseous injuries. ? MRI assessment of ACL-injured knees should include evaluation of the ALL.

     

The value of magnetic resonance imaging in our current management of ACL and meniscal injuries

Magnetic resonance imaging (MRI) is frequently used in the diagnosis of anterior cruciate ligament (ACL) and meniscal injuries. The aim of this retrospective study was to determine the reliability and value of MRI in our management of ACL and meniscal tears. 138 patients who had undergone a MRI to confirm or refute the clinical diagnosis of an ACL or meniscal tear were identified. Those who had subsequently undergone arthroscopy were selected. MRI findings and clinical diagnosis were compared with those at arthroscopy. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy of clinical diagnosis and MRI were then calculated. The overall accuracy for MRI was 91, 68 and 86% for detecting ACL, medial meniscal and lateral meniscal tears, respectively. Accuracy for clinical diagnosis was 90 and 64% for ACL and meniscal tears, respectively. In contrast to other series, our results indicate a lower accuracy of MRI in detecting pathology, especially of the ACL and medial meniscus. We noted a low sensitivity, specificity and positive predictive value but a high negative predictive value rendering MRI most useful as a negative diagnostic tool. We suggest that where symptoms and clinical findings support one of these diagnoses and arthroscopic therapeutic intervention is contemplated, that MRI scanning is not always beneficial. Our current practice of requesting scans to routinely confirm the diagnosis should be altered. Unnecessary MRI scanning increases the financial burden and delays patient treatment. No funding has been received from any sources and no conflicts of interests are stated in the submission of this article.     

MR imaging of anterior cruciate ligament tears: is there a gender gap?

Objective Clinically, females receive anterior cruciate ligament (ACL) tears more commonly than males. We explored whether gender differences exist in MR imaging patterns of ACL tears.Design and patients At 1.5T, two observers evaluated MR examinations of 84 consecutive age-matched patients (42 males, 42 females, aged 16–39) with ACL tears, for mechanism of injury, extent and type of tear, the presence of secondary signs and associated osseous, meniscal and ligamentous injuries.Results The most common mechanism of injury for both females and males was the pivot shift mechanism (67 and 60%, respectively). Females were more commonly imaged in the acute stage of tear than males (98 and 67%, respectively, p=0.001) and more commonly possessed the typical posterolateral tibial bone contusion pattern (88 and 62%, respectively, p=0.0131). Males exhibited a deeper femoral notch sign (2.7 and 2.0 mm, p=0.007) and medial meniscal, lateral collateral ligament and posterior cruciate ligament injuries more commonly than females (48 and 24%, p=0.009, 30 and 7%, p=0.035, 17 and 0%, p=0.035). There was no significant difference between genders for the presence of other secondary signs and contusion patterns, associated lateral meniscal tears, presence of O'Donoghue's triad or associated medial collateral ligament injuries.Conclusion Gender differences in MR imaging patterns of ACL tears exist: females are more commonly imaged in the acute stage and more commonly possess posterolateral tibial bone contusions; males have a more severe presentation than females, associated with more severe lateral femoral condyle and soft tissue injuries.     

A comparison of acute anterior cruciate ligament examinations. Initial versus examination under anesthesia

The preoperative examination, the examination under anesthesia, and the findings at surgery were compared for acutely injured knees that were found at surgery to have anterior cruciate ligament (ACL) tears. The pivot shift was initially positive in only 35% of the knees; however, under anesthesia 98% were positive. The Lachman test was initially positive in 99% of the knees, and under anesthesia, 100%. The anterior drawer sign was present initially in 70% of the knees, and under anesthesia this increased to 91%. Of the 37 patients with isolated ACL tears, only 20 (54%) had initially positive anterior drawer signs. In the knees in which secondary restraints to anterior-posterior motion were injured, this percentage increased to 69% in medial meniscus injury, 82% in lateral meniscus injury and 89.5% in rupture of the medial collateral ligament (MCL). The Lachman test seems relatively unaffected by associated ligamentous or meniscal injuries, but the end point in the Lachman test is absent in all complete ACL tears. The pivot shift phenomenon, which was demonstrable in 98% of patients when tested under anesthesia, may be diminished when there is a MCL injury or absent in partial ACL tears. Experience in performing the Lachman test and in appreciating the quality of the end point will give the examiner a high degree of accuracy in making the diagnosis of an ACL tear without resorting to anesthesia, arthroscopy, or arthrography in most patients.     

Meniscal extrusion in young athletes: associated knee joint abnormalities

OBJECTIVE: The objective of our study was to assess the rate of meniscal extrusion and its connection with common meniscal and joint abnormalities. MATERIALS AND METHODS: MR signs of meniscal extrusion were evaluated retrospectively in 24 rugby and soccer players (40 knees) who are currently free of pain in the knee, impaired mobility, and joint swelling. The control group consisted of 23 consecutive active individuals (36 knees) with no history of knee problems. The criterion for extrusion of the meniscus was defined as a distance of 3 mm or more between the peripheral border of the meniscus and the edge of the tibial plateau measured on coronal images. RESULTS: Forty-eight percent of the athletes' knees and 30% of the control subjects' knees showed evidence of meniscal extrusion. Among the athletes, a significant association between meniscal extrusion and joint effusion (11 cases), meniscal tears (seven cases), and anterior cruciate ligament (ACL) tear (four cases) was found (p < or = 0.004). In the control group, no significant association was found between meniscal extrusion and joint effusion (three cases), meniscal tears (four cases), and ACL tears (two cases) (p = 1.00). A significant association was not found between degenerative change and meniscal extrusion in either the athletes (p = 0.23) or the control subjects (p = 1.00). The most commonly associated knee abnormality was joint effusion in 73% of knees with meniscal extrusion in athletes. CONCLUSION: Meniscal extrusion is a common finding on MRI of athletes' knees. Meniscal extrusion in association with meniscal tear and joint effusion is postulated as a significant injury in athletes and its recognition as such in this group is important because it may prompt orthopedic intervention.     

Diagnosis of cruciate ligament injury using single contrast arthrography

To evaluate the accuracy of arthrography for assessing the status of the anterior cruciate ligament (ACL), 212 arthrograms from 212 knees in 205 consecutive patients undergoing single contrast arthrography and subsequent arthroscopy or arthrotomy were reviewed. Criteria for evaluation of the ACL included the clarity of its radiographic appearance as well as the anterior laxity of the knee as seen on manual stress views. Of the 111 knees having intact ACLs at surgery, 98 (88%) were evaluated correctly by arthrography. Of the 101 knees having a damaged ACL, 85 were read as torn or attenuated on the arthrogram. When the torn and attenuated ligaments were considered separately, accuracy was decreased. Of the 87 ligaments actually torn, 68 (78%) were read as torn and 9 (10%) as attenuated. Of the 14 actually attenuated, 5 (36%) were read as attenuated and 3 (21%) as torn. Of 114 arthrograms read as intact, 98 (86%) were correct. Of 77 arthrograms read as torn, 68 (88%), were correct. Of 21 arthrograms read as attenuated, 5 (24%) were correct. Of 114 torn medial menisci, 112 (98%) were correctly diagnosed, as were 38 (69%) of 55 torn lateral menisci. Sixteen of the 17 missed lateral meniscus tears were in knees with torn medial menisci. Single contrast arthrography is, therefore, highly accurate in distinguishing intact from damaged ACLs. The distinction between torn and attenuated ligaments, however, is not valuable.     

膝关节半月板损伤的MRI与关节镜对照研究

目的评价MRI在膝关节半月板撕裂诊断和评级中的价值。方法参照Mesgarzadeh标准对76位患者78个撕裂半月板的MR影像作回顾性分析,3位MRI主治医师在不知道关节镜检查结果的情况下独自阅片,按Mesgarzadeh的分级标准确定半月板撕裂的类型并记录评定结果,包括联合的前交叉韧带撕裂。结果MRI诊断半月板撕裂的敏感性和特异性分别为92%和87%,Ⅵ型是半月板撕裂中最常见的类型,尤其在发生移位的半月板撕裂中最常见。结论MRI是半月板撕裂伤和交叉韧带损伤的可靠诊断工具。     

Posterior horn lateral meniscal tears simulating meniscofemoral ligament attachment in the setting of ACL tear: MRI findings

PURPOSE: We have noted apparent far lateral meniscal attachment of the meniscofemoral ligament (MFL) with an anterior cruciate ligament (ACL) tear. This study evaluates MFL attachment and association with posterior horn lateral meniscus (PHLM) tear. MATERIALS AND METHODS: Nine months of knee arthroscopy reports were reviewed to classify the PHLM and ACL as torn or normal. After excluding those with prior knee surgery, MR images were reviewed by two radiologists to determine the number of images lateral to PCL, which showed the ligaments of Humphrey and Wrisberg visible as structures separate from the PHLM. Any patient with abnormal PHLM surface signal not continuous with the MFL was excluded. MRI findings were compared with arthroscopy using Student's t test and Fisher's exact test. RESULTS: Of the 54 participants, 5 had PHLM tears and 49 were normal. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear (slice thickness/gap = 3 mm/0.5 mm). There was a significant association between PHLM tear and number of images (p = 0.0028), and between ACL tear and this type of PHLM tear (p = 0.0064). CONCLUSION: Apparent far lateral meniscal extension of a meniscofemoral ligament (greater than or equal to four images lateral to the PCL) should be considered as a possible PHLM tear, especially in the setting of an ACL tear.     

Meniscal tears with fragments displaced in notch and recesses of knee: MR imaging with arthroscopic comparison

PURPOSE: To retrospectively evaluate magnetic resonance (MR) imaging for the depiction of meniscal tears with partially detached meniscal fragments displaced in the intercondylar notch or in the meniscal recesses of the knee. MATERIALS AND METHODS: The institutional review board required neither its approval nor informed patient consent for the retrospective review of patient data; however, informed patient consent had been obtained before the MR imaging examinations were performed. The presence of meniscal tears with notch and recess fragments was determined at MR imaging and at subsequent arthroscopy in 101 consecutive knees to determine the value of MR imaging for the depiction of these lesions. Initial reports were reviewed to evaluate results of initial interpretations. MR images were retrospectively analyzed to determine the value of several MR image signs for the detection of displaced tears with notch or recess fragments. RESULTS: At arthroscopy, 37 (41%) of 91 torn menisci had partially detached fragments. Twenty-six torn menisci had notch fragments, and 14 had recess fragments; three torn menisci had one notch and one recess fragment each. At initial MR image analysis, 38 (36%) of 105 torn menisci had partially detached fragments. Twenty-eight torn menisci had notch fragments, and 13 had recess fragments; one torn meniscus had two recess fragments, and three torn menisci had one notch and one recess fragment each. At initial analysis, sensitivities and specificities were, respectively, 69% and 94% for detection of tears with notch fragments and 71% and 98% for detection of tears with recess fragments. At retrospective analysis of sagittal MR images, the presence of at least one sign indicative of meniscal tear with a notch fragment had sensitivities and specificities, respectively, of 65% and 78% for observer 1 and 77% and 73% for observer 2. The presence of at least one sign indicative of a meniscal tear with a recess fragment had sensitivities and specificities, respectively, of 64% and 77% for observer 1 and 64% and 76% for observer 2. CONCLUSION: Meniscal tears with notch and recess fragments are frequently seen at arthroscopy and can be depicted at knee MR imaging with moderate sensitivity and high specificity.     

Patients with suspected meniscal tears: prevalence of abnormalities seen on MRI of 100 symptomatic and 100 contralateral asymptomatic knees

OBJECTIVE: The purpose of this study was to evaluate the prevalence of MR abnormalities of the knee on the symptomatic and contralateral asymptomatic sides in patients with suspected meniscal tears. SUBJECTS AND METHODS. One hundred patients (mean age, 42.7 years; range, 18-73 years) referred for suspected meniscal tears were prospectively examined with MRI of both knees when the contralateral knee was asymptomatic. The prevalence of various types of meniscal tears and other MR abnormalities was determined. RESULTS: Meniscal tears were found in 57 symptomatic knees and in 36 contralateral asymptomatic knees. In those 57 patients with a meniscal tear on the symptomatic side, the prevalence of asymptomatic tears in the contralateral side was 63% (36/57). Horizontal or oblique meniscal tears were found medially in 32 and laterally in 11 symptomatic knees, and medially in 29 and laterally in eight asymptomatic knees. Radial, vertical, complex, or displaced tears were found medially in 18 and laterally in five symptomatic knees, and medially in five and laterally in none of the asymptomatic knees. Collateral ligament abnormalities were found in 53 symptomatic knees and in six asymptomatic knees. Pericapsular soft-tissue abnormalities were found in 64 symptomatic and in 12 asymptomatic knees. Edema-like bone marrow abnormalities were found in 36 symptomatic and in three asymptomatic knees. CONCLUSION: Horizontal or oblique meniscal tears are frequently encountered in both asymptomatic and symptomatic knees and may not always be related to symptoms. However, radial, vertical, complex, or displaced meniscal tears and abnormalities of the collateral ligaments, pericapsular soft tissues, and bone marrow are found almost exclusively on the symptomatic side and appear to be clinically more meaningful.     

外伤性膝关节前外侧韧带损伤的MR影像特征及相关性分析

目的探讨外伤所致膝关节前外侧韧带损伤病人的MR影像特征,并分析其与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性,为深入研究前外侧韧带对膝关节稳定性的作用提供可靠依据。方法回顾性分析2016年1月—2017年2月间因外伤进行膝关节MRI检查的320例病人(共321膝)的影像资料。采用美国GE公司生产的Signa HDe 1.5 T MR扫描设备,分别行膝关节斜矢状面T1WI、质子密度加权成像(PDWI)和冠状面、横断面PDWI扫描。根据前外侧韧带的完整性和损伤部位对所有病人进行分类统计。采用独立性卡方检验对前外侧韧带撕裂与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性进行分析。结果全部病人膝关节MR影像均可显示前外侧韧带,显示率为100%。151/321膝(47.0%;95%CI为41.6%~52.5%)存在前外侧韧带损伤,其中累及胫骨部、股骨部及半月板部的分别为97膝、96膝及65膝。前交叉韧带撕裂158膝,外侧半月板撕裂98膝,股骨外侧髁挫伤58膝,外侧胫骨平台挫伤71膝,分别与前外侧韧带撕裂具有相关性(均P0.001)。结论 MRI检查可以很好地显示前外侧韧带解剖及其损伤情况。膝关节前外侧韧带损伤与前交叉韧带撕裂、外侧半月板撕裂及膝外侧骨挫伤具有相关性。     

Fat pad adhesion to partially torn anterior cruciate ligament: a cause of knee locking

Isolated damage to the ACL was found on arthroscopic examination of 51 patients who had symptomatic knees. There were 47 male and 4 female patients. The average age of the patients was 26.5 years, ranging from 13 to 43 years. Twenty-four of the patients had isolated partial tears of the ACL, and 27 had isolated complete tears. The purpose of this study was to examine the clinical patterns and arthroscopic findings in these two groups. On examination, 12 patients were found to have locked knees. An additional six patients gave a history of knee locking. All 18 of these patients were clinically suspected of having meniscal damage; however, only partial and complete ACL tears were found at arthroscopy. Of these 18 patients who had locking knees, 15 had a partial tear of the ACL and 3 had a complete tear. Locking was involved primarily in the group with partial ACL tears (15 of 24); only 3 of the 27 patients who had complete tears described locking. Of the 12 patients who had locked knees on examination, all were found to have fibrosis and adhesions of the fat pad and the synovium adjacent to the ACL stump. All 12 of these patients had a partial tear of the ACL. The fibrosis and adhesions were histologically documented in 10 of those 12 patients. The three patients who had partial ACL tears and histories of locking were not observed to have adhesions of synovium to the fat pad, but did have an entrapped remnant of ACL between the tibial plateau and femoral condyle.(ABSTRACT TRUNCATED AT 250 WORDS)     

The anterior intermeniscal ligament of the knee. An anatomic study

The purpose of this study was to identify the presence of the anterior intermeniscal ligament of the knee and to study its attachment patterns and relationships to other anatomic structures within the knee. Fifty unpaired cadaveric knees were dissected. An identifiably distinct anterior intermeniscal ligament was found in 47 specimens (94%). The average length was 33 mm and the average midsubstance width was 3.3 mm. The average perpendicular distance from the anterior intermeniscal ligament to the anterior margin of the tibial insertion of the anterior cruciate ligament was 7.8 mm (range, 2.0 to 13.5). The anterior intermeniscal ligament was the primary attachment for the anterior horn of the medial meniscus in 12 knees (24%); 7 knees (14%) had no tibial insertion and 5 knees (10%) had only a fine fascial tibial connection. Successful arthroscopic evaluation, surgical repair, and meniscal allograft reconstruction can be enhanced by a precise knowledge of the anterior intermeniscal ligament anatomy, especially when identifying the various insertion patterns of the anterior horn of the medial meniscus. A correct understanding of these patterns is helpful for avoiding patient injury during surgical procedures (particularly arthroscopic ACL reconstructions) performed in close proximity to the anterior intermeniscal ligament of the knee.