Postoperative MR evaluation of chondral repair in the knee

Articular cartilage abnormalities of the knee are a cause of significant patient morbidity. Several surgical techniques have been developed to treat these lesions to improve patient symptoms and to delay or prevent the development of osteoarthritis. MRI has been shown to be an accurate non-invasive test for the evaluation of articular cartilage injuries and for evaluating the postoperative knee following chondral repair. As these surgical repair techniques become more commonly performed, is important for radiologists to be familiar with the surgical techniques and the MRI appearance of the postoperative knee including both normal and abnormal findings. In this article, these chondral repair techniques will be reviewed as well those normal and abnormal MRI findings following these surgeries.     

军事训练致膝关节损伤的关节镜下诊断和治疗

目的探讨关节镜对军事训练所致膝关节损伤的诊断及其治疗效果。方法回顾性分析我院2002年1月—2009年10月收治的171例军事训练所致膝关节损伤官兵临床资料,总结军事训练所致膝关节损伤的特点。所有病例均行膝关节MRI检查,并在关节镜下行手术治疗或关节探查清理。对比MRI检查结果的准确率。术前、术后均对所有病例行膝关节Lysholm评分及主观评价。结果本组病例随访时间10～22月,Lysholm评分术前(42.1±3.7)分,术后为(84.3±2.3)分。无因手术而症状加重及发生血管神经损伤及感染等并发症。结论关节镜既有诊断价值又是治疗手段,关节镜检查可全面评估膝关节的损伤程度,微创治疗膝关节军事训练疾患,相比其他治疗手段具有明显的优越性。     

MR imaging evaluation of the postoperative knee: ligaments, menisci, and articular cartilage

The surgical management of knee injuries has increased in recent years. Postoperative magnetic resonance (MR) imaging of the knee following surgical intervention serves an important role in the diagnostic evaluation of patients with recurrent or residual symptoms following surgical intervention. MR imaging additionally assists in the noninvasive documentation of temporal changes at the surgical site potentially reflective of procedural success, or failure. Background understanding of the common surgical procedures performed, their normal postoperative MR imaging appearance, and imaging features of potential procedural complications are essential in the accurate evaluation of patients following prior knee surgery. The focus of the following article is to review the clinical and MR imaging features of the postoperative knee following prior surgical treatment of ligamentous, meniscal, and articular cartilage injuries of the joint.     

MRI诊断髌下脂肪垫损伤的价值

目的探讨膝关节髌下脂肪垫(infrapatellar fat pad,IFP)损伤的磁共振成像(MRI)特点及临床应用价值。方法回顾性分析我院经临床综合诊断或临床随访明确诊断为IFP损伤的111例患者,归纳总结其特征性MRI表现并分级。结果111例中,左膝57例,右膝39例,双膝15例。共126个膝关节根据IFP的信号、裂隙及形态改变进行损伤程度分级轻度54个(42.9%),中度43个(34.1%),重度29个(23.0%)。根据IFP损伤程度指导临床给予相应治疗,终止治疗4~8周随访。治疗前后膝关节VAS评分有显著差异(P<0.05)。结论MRI能准确评估IFP损伤部位及严重程度,为临床治疗提供影像学依据并有较好的指导作用。     

喉及下咽癌的MRI评价(兼与CT比较)

目的：探讨MRI对喉及下咽癌术前分期及术后评价中的临床应用价值。方法：26例喉及下咽癌患者(原发性肿瘤23例、术后复发3例)进行MRI扫描，分析其MRI表现，将结果与手术病理及CT扫描作比较。结果：MRI能较好地显示肿瘤的部位、大小及其侵犯范围。MRI对术前肿瘤分期及诊断颈部淋巴结转移的准确性为91％。高于CT扫描的87％及83％。结论：MRI扫描喉及下咽癌术前分期及术后评价有较大的帮助。     

Prevalence of meniscal radial tears of the knee revealed by MRI after surgery

OBJECTIVE: Meniscal resection decreases the ability of the meniscus to evenly distribute forces placed on it. These forces are oriented centrifugally on the meniscus by normal weight-bearing and are distributed by circumferentially oriented fibers. This alteration may predispose the knee to radial tears after surgery. SUBJECTS AND METHODS: One of three musculoskeletal radiologists prospectively interpreted 100 consecutive postoperative MRI examinations of the knee. A prospective MRI report was generated for the referring orthopedic surgeon, and prospective MRI interpretations were correlated with arthroscopic findings (n = 63). MRI examinations on those patients who underwent second-look arthroscopy were retrospectively reviewed by three musculoskeletal radiologists who reached a consensus on the prevalence of new postoperative meniscal radial tears. MRI criteria for radial tear diagnosis were used as outlined by Tuckman et al.: truncation, abnormal morphology, lack of continuity, absence of the meniscus, or any combination of those criteria on one or more MR images. An additional criterion used was abnormal increased signal in that area on T2-weighted images. RESULTS: Thirty-two of the 100 patients had meniscal radial tears on prospective MRI interpretations. In 29 of these 32 patients, second-look arthroscopy confirmed meniscal radial tears in the areas described on the MRI examinations. Five additional radial tears were shown on second-look arthroscopy that were not seen on prospective MRI interpretations. Two of those additional five radial tears were seen on consensus retrospective MRI review. CONCLUSION: In this study, a 32% prevalence of meniscal radial tears in the postoperative knee was present on prospective MRI interpretations as opposed to a reported 14% prevalence in the nonoperated knee. Meniscal resection decreases the ability of the meniscus to evenly distribute forces placed on it. This circumstance may increase the prevalence of meniscal radial tears in the postoperative knee. New meniscal radial tears are common in patients presenting with pain after knee surgery.     

膝关节骨挫伤的低场MRI诊断价值探讨

目的探讨低场MRI对膝关节骨挫伤的诊断价值。方法回顾性分析72例膝关节骨挫伤的低场MRI表现。结果本组72例X线平片均未见异常。MRI检查72例骨挫伤在T1WI呈低信号、T2WI呈高信号或混杂高信号,境界不清,在STIR像上呈显著高信号,境界清晰;其中51例合并半月板损伤,43例合并韧带损伤,19例合并关节软骨损伤,3例合并骺板损伤,64例合并关节积液。结论低场MRI能清楚显示骨挫伤的病变特点及严重程度,准确判断关节其它结构的损伤,可为临床治疗及愈后的评估提供依据。     

MR Arthrography of the Knee

The role of magnetic resonance imaging (MRI) in the evaluation of musculoskeletal injuries has been well documented during the last decade. There remain several important clinical situations in which noncontrast MRI has been disappointing. In the knee, magnetic resonance arthrography (MRA) can supplement noncontrast MRI in the evaluation of specific conditions, such as postoperative meniscus and osteochondritis dissecans. MRA significantly increases accuracy in the diagnosis of meniscal retear, as is seen in cases in which there has been a meniscal resection of more than 25% or after meniscal suturing. Also, in the evaluation of osteochondritis dissecans, the addition of intra-articular contrast has proved beneficial. Aside from assessing the integrity of the articular cartilage surface and documenting loose bodies, the contrast allows the clinician to distinguish fibrovascular granulation tissue from fluid partially or completely surrounding the osteochondritic fragment. These topics are discussed in this article.     

US and MR imaging of the postoperative knee

Constantly increasing number of surgical procedures on the soft tissues of and around the knee generates the need for postoperative soft tissue assessment. Sports medicine is constantly seeking new--faster, better, more efficient--ways to help patients, especially competitive athletes to come back to their full activity as soon as possible. One of the important factors in that acceleration is postoperative tissue assessment. It helps the clinician making better decisions in terms of the rehabilitation stages, come back to basic and sport-specific training and finally in letting the patient put a full load on the operated structure. The healing of the collagen structure cannot only be guided by patient's pain. Diagnostic imaging methods such as US and MRI, which focus on the soft tissue assessment are best fitted to do the job. They also help in the diagnostics of the reinjuries of operated structures. Often criteria used for basic diagnostics do not fit the need of assessment of the structure which underwent an initial injury, was operated, healed and often reinjured again. Criteria used for regular injury diagnostics are in most cases seriously modified. Moreover the whole matter of structure evaluation after an injury and medical intervention leaves a lot of slippery ground and should be carefully studied before taking the challenge of judging the surgeon and the natural healing processes. Diagnostic judgment has much more impact on the operated patient than the primary injury diagnosis. Depending on the author both MRI and US are pointed out as the best imaging methods in terms of postoperative knee assessment. In fact both methods can be complementarily used in the postoperative follow up. Depending on the operated structure the choice of methods usually depends on local equipment availability and personal doctor's experience. MRI is probably best fitted for evaluation of the internal knee structures such as cruciate ligaments and hyaline cartilage on the tibia and patella. US is my choice always in the evaluation of the superficially located connective tissue structures, femoral cartilage and menisci. In both cases the learning curve is nearly flat, frustrating and dedicated to only those radiologist who know how their surgeon looks like with and without a surgical mask. Tight surgeon-radiologist cooperation and information exchange is essential in this kind of diagnostics.     

Tunnel placement in anterior cruciate ligament reconstruction: MRI analysis as an important factor in the radiological report

 Objective. Correct placement of tunnels for anterior cruciate ligament (ACL) reconstruction is of prime importance for the clinical outcome of the patient. In this study, the possibility of using MRI to document tunnel placement and provide a more comprehensive report following ACL reconstruction was explored at no additional cost in patients scheduled for routine knee MRI. Design and patients. One year after ACL reconstruction, 45 patients underwent clinical examination (IKCD score), radiographic examination, and MRI using a 1.5-T unit. Results. Twenty patients with good tibial and femoral attachment results were found at clinical examination to have a stable knee joint with a full range of motion. In 25 patients with suboptimal placements, examination showed either a stable knee with a decreased range of motion or instability with a normal range of motion. Conclusion. Patients’ clinical outcome, and the radiographic and MRI findings, correlated closely with the quality of operative tunnel placement. A record of this finding is important for completeness of the radiological report. Furthermore the MRI findings can be used to improve the surgical quality of tunnel placement. Because tunnel placement can be shown adequately with radiography, however, MRI cannot be justified for this reason alone, so such assessment is advised only when MRI is needed to show all postoperative features.     

Magnetic resonance imaging in a military setting: a utilization analysis

A prospective study was conducted to evaluate the use of magnetic resonance imaging (MRI) by orthopedic surgeons and residents versus the use of MRI by non-orthopedically trained health care providers in diagnosing knee pathology. Fifty patients initially evaluated by members of one of these groups who underwent subsequent knee MRI evaluation were selected to participate. Two orthopedic examiners individually examined all patients, recording clinical diagnosis and the merit of MRI evaluation in each case. Clinical accuracy, sensitivity, and specificity were compared between groups based on MRI findings. Diagnostic accuracy was similar; however, the orthopedic group displayed greater sensitivity, suggesting better clinical assessment. The study examiners observed both groups using MRI equally inappropriately and found 62% of the imaging studies unjustified. We conclude that knee MRI is used inappropriately in the current military setting. An algorithm is proposed to guide the future use of MRI in the diagnosis and management of knee pathology.     

Magnetic resonance imaging of the knee.

Magnetic resonance imaging (MRI) has revolutionised diagnostic imaging of the knee. It has evolved significantly since Kean described healthy and pathologic knee anatomy in 1983. This innovative technology allows superior soft-tissue detail with multiplanar imaging capability that provides accurate evaluation of intra- and extra-articular structures of the knee not demonstrated with other imaging modalities. The development and advancements in MRI and the introduction of high-resolution coils have provided a noninvasive, nonoperator dependent, cost effective means to diagnose knee pathology. MRI is well tolerated by patients, widely accepted by evaluating physicians, and assists in distinguishing pathologic knee conditions that may have similar clinical signs and symptoms (i.e. meniscal tears, osteochondral lesions). This paper presents an overview of MRI of the knee and focuses on the MRI findings in a number of common pathologic conditions.     

MR imaging evaluation of the postoperative knee

The increased number of patients undergoing arthroscopy or surgery of the knee for sports medicine injuries is leading to increased numbers of patients who require imaging after surgery because of failure to improve, recurrent symptoms, or new injury. As in preoperative patients, magnetic resonance (MR) imaging is the most valuable imaging method for postoperative evaluation of the knee. Surgical changes increase the difficulty of diagnosis of abnormalities in the knee with MR imaging. MR arthrography with direct intraarticular injection of contrast material can help improve evaluation of the postoperative meniscus and possibly help improve evaluation of anterior cruciate ligament grafts in patients after surgery. Recognition of the normal postoperative MR imaging appearance of the structures in the knee and of abnormalities is essential to accurate MR imaging evaluation of these patients.     

Longitudinal evaluation of cartilage repair tissue after microfracture using T2-mapping: a case report with arthroscopic and MRI correlation

A man sustained a left knee injury which led to full-thickness chondral defects of the trochlear groove and lateral femoral condyle. Both areas were treated with microfractures and evaluated at 5 months and 2 years with standard MRI scans, T2 relaxation maps, and arthroscopy. At 5-months post-microfracture repair, the patient complained of recurrent anterior knee pain. While standard MRI imaging was inconclusive with regards to a potential recurrent defect at the trochlear groove microfracture area, T2 relaxation maps established the integrity of the surface layer which was confirmed by arthroscopic evaluation. At 2 years, imaging studies revealed repair tissue loss with low T2 values at the trochlear repair site. The failure of the trochlear site and the integrity of the lateral femoral condyle repair sites were confirmed by arthroscopy. This case report is the first one to provide a correlation of T2 mapping MRI findings with arthroscopic confirmation in the context of microfracture repairs. The study provides evidence for the clinical utility of T2 relaxation maps for the postoperative assessment of microfractures and raises the potential for T2 mapping MRI as a tool to evaluate these repair procedures.     

Assessment of rotatory laxity in anterior cruciate ligament-deficient knees using magnetic resonance imaging with Porto-knee testing device

Purpose  

Objective evaluation of both antero-posterior translation and rotatory laxity of the knee remains a target to be accomplished. This is true for both preoperative planning and postoperative assessment of different ACL reconstruction emerging techniques. The ideal measurement tool should be simple, accurate and reproducible, while enabling to assess both “anatomy” and “function” during the same examination. The purpose of this study is to evaluate the clinical effectiveness of a new in-house-developed testing device, the so-called Porto-knee testing device (PKTD). The PKTD is aimed to be used on the evaluation of both antero-posterior and rotatory laxity of the knee during MRI exams.     

Osteonecrosis of the patella: diagnostic imaging perspective

Disability from knee dysfunction has important implications on a patient's performance of simple day-to-day tasks, work-related duties, and leisure activities, including sports. Diagnostic imaging is of fundamental importance in the clinical evaluation of the patient with knee pain. The use of magnetic resonance imaging (MRI) for the assessment of knee pain and dysfunction has increased over the past few years as orthopedic surgeons and radiologists have familiarized themselves with the unique advantages of this modality. Magnetic resonance imaging provides a comprehensive evaluation of a wide spectrum of intra-articular and extra-articular pathologic conditions involving the knee. One of the most common indications for MRI of the knee is osteonecrosis. Osteonecrosis of the patella is unusual, and it is a well-documented cause of knee pain. After a brief overview of the anatomy of the patella, the diagnosis of osteonecrosis at this site by conventional radiography, MRI, and other imaging methods is focused on in this review.     

膝关节痛风性关节炎的MRI诊断

目的 探讨膝关节痛风性关节炎的MRI特征性表现.资料与方法 回顾性分析7例经手术、病理证实为膝关节痛风性关节炎的MRI表现.所有病例均做SE序列T1WI和FSE序列T2WI.其中4例做了钆喷酸葡胺(Gd-DTPA)增强扫描.结果 膝关节骨质侵蚀破坏5例,股骨髁4例,髌骨下缘1例;股骨髁间窝区域、髌下脂肪区和/或髌韧带周围软组织见团块状病灶6例.全部痛风石病灶T1WI均呈低至中等信号;T2WI有2例呈低信号,3例有低信号病灶和低至稍高混杂信号病灶,另2例则为高信号.4例增强后,病灶无强化1例,轻度不均匀强化1例,病灶边缘强化2例.结论 膝关节痛风性关节炎的MRI特征性表现常是T1WI和T2WI均呈低至中等信号的肿块状病灶,且具边缘强化,其对膝关节痛风性关节炎的诊断很有价值.     

MR and CT arthrography of the knee

MR and CT arthrography are important imaging modalities for the assessment of the knee in certain situations. Indications for MR arthrography of the knee include assessment of the postoperative meniscus, the presence of chondral and osteochondral lesions, and the presence of intra-articular bodies. The major indication for CT arthrography is evaluating suspected internal derangement in patients who are unable to undergo MRI. In addition to reviewing the established clinical indications for MR and CT arthrography of the knee, the commonly used techniques, normal variants that can simulate disease, and the most commonly found pathologies that can be diagnosed with these modalities are discussed. Potential indications that are not currently well established in the literature including the evaluation of anterior cruciate ligament injury and autologous chondrocyte implants are examined. Where appropriate, the literature on controversial topics or diagnoses is reviewed. The use of conventional imaging versus CT and MR arthrography is also compared.     

膝关节前交叉韧带损伤的MRI诊断

本文报告了２８例膝关节前交叉韧带（ＡＣＬ）损伤的分类及七种主要的ＭＲＩ的表现，同时将１５例正常ＡＣＬ及ＰＣＬ的ＭＲＩ作为对照，对ＡＣＬ损伤的ＭＲＩ特点及病理基础，诊断价值的临床意义进行了讨论。指出矢状位（倾斜１５°）是观察ＡＣＬ撕裂的最重要影像，对膝关节外伤的病人进行及时的ＭＲＩ检查极为重要。