膝关节损伤的MR应用价值

目的 :分析膝关节损伤的MR表现并评价其应用价值。方法 :选择 60例经临床或手术证实的膝关节损伤患者 ,回顾性分析、总结其MR表现。采用 1 .0TMR扫描机 ,常规应用矢状位 ,SET1 W、T2 W ,冠状位T1 W、T2 W成像。结果 :2 9例半月板损伤 ,其中Ⅰ° 1 0例 ,Ⅱ°1 2例 ,Ⅲ°7例 ;前交叉韧带损伤 1 8例 ,撕裂 2 2例 ;后交叉韧带损伤 7例 ,撕裂1例 ;内侧侧副韧带损伤 2 8例 ,撕裂 1 7例 ;外侧侧副韧带损伤 1 2例 ,撕裂 9例 ;韧带损伤表现为韧带不同程度增粗 ,但韧带连续性仍然存在 ,正常低信号内出现不规则高信号影 ,韧带撕裂表现为韧带明显增粗 ,呈弥漫性高信号 ,韧带的连续性部分或完全中断 ;股骨下端或胫骨上端骨质损伤 9例 ;关节积液 54例 ;多种损伤可同时出现。结论 :MR检查可很好显示膝关节损伤的各种表现 ,可作为膝关节损伤检查的重要或首选手段     

膝关节交叉韧带损伤的MRI诊断

目的 :探讨MRI对膝关节交叉韧带损伤的诊断价值。方法 :回顾性分析 2 5例经手术或关节镜证实的前、后交叉韧带损伤患者 ,MR检查采用SE、TSE矢状位、冠状位及横断位T1WI、T2 WI及STIR。结果 :2 5例交叉韧带损伤中 ,部分性撕裂 16例 ,完全性撕裂 9例。MRI诊断交叉韧带部分性撕裂和完全性撕裂的符合率分别为 87.5 %和 88.9%。结论 :MR能较准确地诊断膝关节交叉韧带损伤及其并发症 ,为临床制订治疗方案提供可靠依据。     

Knee injuries: high-resolution MR imaging

Recent technologic advances have made high-resolution magnetic resonance (MR) imaging of the knee a clinical reality. Ten healthy volunteers and 30 patients with suspected knee injuries were imaged using receive-only surface coils and two-dimensional multisection or three-dimensional selective acquisition techniques. Arthroscopic and/or surgical correlation was available in 15 patients. Tears of the cruciate ligament, medial collateral ligament, and meniscus are illustrated. Nonorthogonal views of the anterior cruciate ligament are useful for demonstrating both femoral and tibial attachments in the same section. The posterior cruciate ligament is usually well seen on sagittal views. T2-weighted images are helpful for demonstrating collateral ligament tears and meniscal tears when joint effusion is present. Thin sections (1-5 mm) are necessary to define many meniscal and cruciate tears. High-resolution, thin-section MR imaging can be used to diagnose soft-tissue injuries of the knee and has the potential to become a major imaging method in the evaluation of knee injuries.     

Double-contrast arthrography of the knee in traumatic capsular-ligamentous lesions. A critical review

The authors conducted a statistical study and a critical review on a series of 1,300 patients examined with double-contrast fluoroscopically guided knee arthrography using a simple examination technique. Arthrographic diagnoses were subsequently compared with arthrotomic (500 patients), arthroscopic (350 patients), and clinical (450 patients) diagnoses. The critical review pointed out the high diagnostic accuracy (90%) and the good sensitivity (87%) of arthrographic examination in patients affected with pathologic conditions of the cruciate ligaments. In collateral ligament diseases and in capsular ruptures arthrographic sensitivity was not as high but still acceptable (74%). Capsular tears and medial collateral ligament tears can be identified when contrast medium is seen leaking from the knee joint. Cruciate ligament tears may be partial or complete: if a tear is partial the synovial surface of the cruciate ligament cannot be identified the cruciate ligament is wavy, lumpy, or focally thin, while in complete tears the synovial surface of the cruciate ligament cannot be identified either entirely or partially.     

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。     

Knee dislocations: a magnetic resonance imaging study correlated with clinical and operative findings

OBJECTIVES: Our objectives were to determine retrospectively the prevalence, patients' demographics, mechanism of injury, combination of torn ligaments, associated intra-articular and extra-articular injuries, fractures, bone bruises, femoral-tibial alignment and neurovascular complications of knee dislocations as evaluated by magnetic resonance (MR) imaging. MATERIALS AND METHODS: From 17,698 consecutive knee examinations by magnetic resonance imaging (MRI) over a 6-year period, 20 patients with knee dislocations were identified. The medical records of these patients were subsequently reviewed for relevant clinical history, management and operative findings. RESULTS: The prevalence of knee dislocations was 0.11% [95% confidence interval (95% CI) 0.06-0.16)]. There were 16 male patients and four female patients, with ages ranging from 15 years to 76 years (mean 31 years). Fifteen patients had low-velocity injuries (75%), of which 11 were amateur sports related and four were from falls. Four patients (20%) had suffered high-velocity trauma (motor vehicle accidents). One patient had no history available. Anatomic alignment was present at imaging in 16 patients (80%). Eighteen patients had three-ligament tears, two had four-ligament tears. The four-ligament tears occurred with low-velocity injuries. The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were torn in every patient; the lateral collateral ligament (LCL) was torn in 50%, and the medial collateral ligament (MCL) in 60%. Intra-articular injuries included meniscal tears (five in four patients), fractures (eight in seven patients), bone bruises (15 patients), and patellar retinaculum tears (eight partial, two complete). The most common extra-articular injury was a complete biceps femoris tendon tear (five, 25%). There were two popliteal tendon tears and one iliotibial band tear. One patient had received a vascular injury following a motor vehicle accident (MVA) and had been treated prior to undergoing MRI. Bone bruises (unrelated to fractures), four-ligament tears, biceps femoris tears, and popliteus tendon tears were encountered only in the low-velocity knee dislocations. Twelve were treated surgically, five conservatively, and three had been lost to follow-up. The biceps femoris tendon was repaired in every patient who was treated surgically. CONCLUSIONS: Knee dislocations occurred more commonly in low-velocity injuries than in high-velocity injuries, predominantly affecting amateur athletes. Biceps femoris tendon tears were the most common extra-articular injury requiring surgery. Neurovascular injury (5%) was uncommon. At imaging, femoral-tibial alignment was anatomic in the majority of patients.     

0.2-Tesla magnetic resonance imaging of internal lesions of the knee joint: a prospective arthroscopically controlled clinical study

The results of magnetic resonance imaging (MRI) were compared with those of arthroscopy in a prospective series of 244 patients. A dedicated system for MRI of limbs and peripheral joints – the 0,2-T Artoscan (Esaote, Italy) – was used for imaging knee joint lesions. T1-weighted spin-echo sagittal images, T2-weighted gradient-echo coronal images, and axial views for lesions of the femoropatellar joint were acquired. Paraxial sagittal and oblique coronal views were obtained for imaging of the cruciate ligaments. This protocol allowed excellent visualization of the cruciate ligaments and medial and lateral meniscus in almost all patients. Compared with arthroscopy performed within 48 h after imaging, the sensitivity, specificity, and accuracy were respectively 93%, 97%, and 95% for tears of the medial meniscus; 82%, 96%, and 93% for tears of the lateral meniscus; 100%, 100%, and 100% for tears of the posterior cruciate ligament; 98%, 98%, and 97% for tears of the anterior cruciate ligament; and 72%, 100%, and 92% for full-thickness articular cartilage lesions. The examination can be performed within 30–45 min at lower cost than diagnostic arthroscopy. MRI with a 0.2-T magnet is a safe and valuable adjunct to the clinical examination of the knee and an aid to efficient preoperative planning. Received: 13 October 1997 Accepted: 3 March 1998     

M.R. imaging of the knee: a prospective trial using a low field strength magnet

A double blind prospective study involving fifty patients was performed to assess the diagnostic accuracy of knee MR Imaging using a 0.3 Tesla low field strength scanner. The study compared MR Imaging with arthroscopy. The overall accuracy found for the detection of meniscal tears was 92% and cruciate ligament tears 95%. These results compare favourably with other diagnostic modalities including knee arthroscopy. MR Imaging is good at showing meniscal lesions, especially cleavage tears, though some bucket-handle tears produced no MR abnormality. MR Imaging is very accurate at demonstrating complete cruciate ligament tears. Partial cruciate ligament tears often produced no positive MR findings and in no patients could any features be found to indicate ligamentous laxity.     

Knee Injuries in Sailboarding

Sailboarding is an exciting sport, but it does involve some risk for injury. In this study of 21 knee injuries that occurred during sailboarding over a 2-year period, 12 were isolated medial collateral ligament (MCL) sprains, 4 were meniscus tears, and 5 involved joint instability. The MCL sprains were directly related to the use of the foot straps on the sailboard. Conservative treatment was successful for the MCL sprains; the meniscus tears were treated with arthroscopic surgery. Improved foot straps designed to release the foot more readily may help reduce knee injuries.     

Function of the normal meniscus and consequences of meniscal resection

The principal functions of the meniscus are load transmission and shock absorption, based on the meniscal collagen architecture, the biochemical fluid composition, and the proteoglucan-collagen meshwork. The mobile menisci transmit 50-90% of load over the knee joint, depending on knee flexion angle, femoral translation and rotation. The meniscus contributes to knee joint proprioception and probably also to joint stability. Late consequences of total and partial meniscectomy are radiographic osteoarthritis, with a varying percentage of these patients having symptoms. Malalignment, concomitant articular cartilage lesions, and ligament instability are absolute risk factors, while age, lateral compartment, and continued sport activity are relative risk factors. Acute reinsertion of meniscal tears in the red-red or red-white zones can be performed successfully by arthroscopic technique. Also in chronic tears stable healing can be expected in most cases, if the scar tissue is resected.     

MR imaging of the knee. Part I. Traumatic disorders

One hundred thirty patients with a diversity of knee joint injuries were evaluated with a high-resolution magnetic resonance (MR) imaging technique. The authors report the accuracy of this technique in the evaluation of 105 patients with suspected meniscal tears, 26 patients with suspected cruciate ligament tears, and eight patients with suspected patellar tendon injuries. Of those menisci rated as definitely or probably torn on MR imaging, 80% were found to be torn at subsequent arthroscopy. The predictive value of negative MR imaging results was 100%. MR imaging was 92% accurate in predicting the clinical outcome in patients with suspected meniscal tears who did not undergo surgery. MR permitted complete disruption of the patellar tendon to be differentiated from partial tears, ligamentous inflammation, and localized effusion of the infrapatellar bursa. Injuries to the anterior and posterior cruciate ligaments were identified on MR images, and the status of synthetic grafts of the anterior cruciate ligament was ascertained.     

Preoperative instrumented testing of anterior and posterior knee laxity

A prospective study was performed on 50 patients who were thought or suspected to have cruciate ligament tears. Each patient had a clinical examination preoperatively and under anesthesia and instrumented examination using the MedMetric KT-1000 arthrometer, Stryker knee laxity tester, and Genucom knee analysis. The diagnosis was confirmed by arthrotomy or arthroscopy. Thirty had acute knee injuries (within 2 weeks), 9 had subacute (2 weeks to 3 months), and 11 had chronic injuries. The surgical findings demonstrated that five had other maladies, but no cruciate ligament tears. Two had a partial ACL tear, and the remaining 43 patients had at least one cruciate tear. The preoperative clinical examination for cruciate ligament integrity was completely correct in 92%, correct but incomplete in 6%, and incorrect in 2%. Examination under anesthesia was correct in 98%, the KT-1000 was correct in 75% (involved knee minus noninvolved knee was greater than or equal to 3 mm laxity equal to ACL tear), the Stryker was correct in 75%, and Genucom in 70%. The average laxity of those with ACL tears was 4.4 mm with the KT-1000, 4.6 mm with the Stryker, and 2.0 mm with the Genucom. The methods of testing with the Stryker and the KT-1000 are similar and the laxity recorded in patients with a torn ACL were almost identical. However, the KT-1000 can be used to identify the quadriceps neutral position and therefore more accurately determine PCL instability. The Genucom has the most versatility, but the laxity recorded in patients with a torn ACL was significantly lower than the other devices.(ABSTRACT TRUNCATED AT 250 WORDS)     

Patellotibial contusions in anterior cruciate ligament tears

Bone contusions are an important ancillary finding of many knee injuries. Not only are they a source of pain, they may suggest a mechanism of injury or a specific derangement of the knee joint. We have encountered a small number of patients being evaluated for anterior cruciate ligament (ACL) tears with unexplained patellar and tibial edema at magnetic resonance (MR) imaging. We present three individuals with contusions of the inferior patella with a corresponding contusion of the anteromedial tibial plateau. Internal derangements in these patients were similar to other individuals with acute ACL tears, however osseous contusions were more widespread. In conclusion, patellotibial contusions are rare and may indicate an injury with forces greater than usually encountered in most ACL tears. A careful search for uncommon associated injuries is prudent in these high-energy knee injuries.     

Characteristics of displaceable and nondisplaceable meniscal tears at kinematic MR imaging of the knee

PURPOSE: To prospectively determine if kinematic magnetic resonance (MR) imaging of the knee may demonstrate displacement of menisci with tears and, if so, to characterize displaceable and nondisplaceable meniscal tears. MATERIALS AND METHODS: The study was approved by the hospital's review board, and informed consent was obtained. Forty-two patients (30 men, 12 women; mean age, 36.9 years) with 43 arthroscopically documented meniscal tears visible at 1.5-T MR imaging underwent kinematic MR imaging with an open-configuration 0.5-T MR imager with their knees in supine neutral, supine with 90 degrees flexion and external or internal rotation, and upright weight-bearing positions. Analysis of meniscal movement was performed in different knee positions in the coronal MR imaging plane. Meniscal displacement--that is, meniscal movement of 3 mm or more (in the medial direction for the medial meniscus, in the lateral direction for the lateral meniscus)--was compared with the patient's pain level as assessed with a visual analog scale by using analysis of variance. RESULTS: Between the different knee positions, meniscal displacement of 3 mm or more (displaceable meniscal tears) was noted in 18 (42%) of 43 menisci with tears. Simultaneous occurrence of grade II or III ipsilateral collateral ligament lesions was present in all 18 displaceable meniscal tears, whereas a normal-appearing collateral ligament or collateral ligament lesion (grade I) was present in 22 of 25 nondisplaceable tears (P < .05). Displaced menisci most commonly had complex, radial, or longitudinal tear configurations (16 of 18, 89%). Patients with displaceable meniscal tears had significantly more pain than did patients with nondisplaceable meniscal tears (P < .001), independent of the concomitant knee abnormalities. CONCLUSION: Displaceable meniscal tears usually have longitudinal, radial, or complex configurations; such tears are associated with substantial ipsilateral collateral ligament lesions and pain.     

磁共振STIRFIR序列对膝关节外伤的诊断准确性

目的 评价短反转时间快速反转恢复（STIRFIR）序列对膝关节外伤的诊断准确性。方法 60例膝关节外伤的患者均经磁共振检查，其中，35例有关节镜资料证实，对膝关节外伤的患者于外伤后2h～7d行STIR FIR序列、扰相梯度T2加权（Spoiled gradient T2 Weighted Image，GRE T2WI）序列并对其磁共振影像（MRI）表现进行比较分析。结果 扰相GRE T2WI序列显示前交叉韧带损伤40例，后交叉韧带损伤24例，半月板损伤21例，骨挫伤21例，骨挫伤区或其周围发现隐性骨折线19条；STIR序列检出前交叉韧带损伤41例，后交叉韧带损伤25例，半月板损伤21例，骨挫伤60例，骨挫伤区或其周围发现隐性骨折线182条。结论 与GRE T2WI序列比较，STIR FIR序列对膝关节外伤中的骨挫伤、隐性骨折具有更明显的诊断优势，可作为膝关节外伤MRI检查的常规序列。     

Risk of tearing the intact anterior cruciate ligament in the contralateral knee and rupturing the anterior cruciate ligament graft during the first 2 years after anterior cruciate ligament reconstruction: a prospective MOON cohort study

BACKGROUND: The risk of tear of the intact anterior cruciate ligament in the contralateral knee after anterior cruciate ligament reconstruction of the opposite knee and the incidence of rupturing the anterior cruciate ligament graft during the first 2 years after surgery have not been extensively studied in a prospective manner. Clinicians have hypothesized that the opposite normal knee is at equal or increased risk compared with the risk of anterior cruciate ligament graft rupture in the operated knee. HYPOTHESIS: The risk of anterior cruciate ligament graft rupture and contralateral normal knee anterior cruciate ligament rupture at 2-year follow-up is equal. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The Multicenter Orthopaedic Outcome Network (MOON) database of a prospective longitudinal cohort of anterior cruciate ligament reconstructions was used to determine the number of anterior cruciate ligament graft ruptures and tears of the intact anterior cruciate ligament in the contralateral knee at 2-year follow-up. Two-year follow-up consisted of a phone interview and review of operative reports. RESULTS: Two-year data were obtained for 235 of 273 patients (86%). There were 14 ligament disruptions. Of these, 7 were tears of the intact anterior cruciate ligament in the contralateral knee (3.0%) and 7 were anterior cruciate ligament graft failures (3.0%). CONCLUSION: The contralateral normal knee anterior cruciate ligament is at a similar risk of anterior cruciate ligament tear (3.0%) as the anterior cruciate ligament graft after primary anterior cruciate ligament reconstruction (3.0%).     

A technique for arthroscopic anterior cruciate ligament repair

Treatment options for anterior cruciate ligament (ACL) tears include rehabilitation therapy, derotation therapy, and surgical repair or reconstruction. This article presents an arthroscopic technique for reattaching the ACL that offers some advantages over other procedures. Advantages include avoiding exposure of the knee joint, improved cosmetic results, and reduced recuperation time.     

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.     

Functional bracing after anterior cruciate ligament reconstruction: a prospective, randomized, multicenter study

BACKGROUND: Bracing after anterior cruciate ligament reconstruction is expensive and is not proven to prevent injuries or influence outcomes. PURPOSE: To determine whether postoperative functional knee bracing influences outcomes. STUDY DESIGN: Prospective, randomized, multicenter clinical trial. METHODS: One hundred volunteers from the 3 US service academies with acute anterior cruciate ligament tears were randomized into braced or nonbraced groups. Only those subjects with anterior cruciate ligament tears treated surgically within the first 8 weeks of injury were included. Patients with chondral injuries, significant meniscal tears, or multiple knee ligament injuries were excluded. Surgical procedures and the postoperative physical therapy protocols were identical for both groups. The braced group was instructed to wear an off-the-shelf functional knee brace for all cutting, pivoting, or jumping activities for the first year after surgery. RESULTS: Ninety-five subjects were available with a minimum 2-year follow-up. There were no statistically significant differences between groups in knee stability, functional testing with the single-legged hop test, International Knee Documentation Committee scores, Lysholm scores, knee range of motion, or isokinetic strength testing. Two braced subjects had reinjuries, and 3 nonbraced subjects had reinjuries. CONCLUSIONS: In this young, active population, postoperative bracing does not appear to change the clinical outcomes after anterior cruciate ligament reconstruction.     

Pitfalls in knee arthrography.

Sources of error in performing and interpreting knee arthrograms are discussed. Normal anatomic structures and technical factors can simulate tears in most areas of both the medial and lateral menisci. These pseudotears, as well as unrecognized true tears, occur more commonly in the posterior horn of the medial meniscus. Inferior meniscal recesses and coronary ligament irregularities of the posterior medial meniscus often represent incomplete tears. Diagnostic, etiologic, and therapeutic aspects of these recesses, or pseudorecesses, are discussed. Excessive intra-articular positive contrast medium may become localized and simulate a loose body in the joint.