骨软骨损伤严重程度：1961年Outerbridge分级概述：2018年

发表者：陶可人已读

骨软骨损伤严重程度：1961年Outerbridge分级概述：2018年

作者：Casey Slattery, Christopher Y Kweon.

作者单位: Department of Orthopaedics ＆ Sports Medicine, University of Washington, Seattle, WA, USA.

译者：陶可（北京大学人民医院骨关节科）

Outerbridge软骨损伤分类系统的观察者间和观察者间一致性从一般到优良不等。这种不一致的可靠性仍然是该系统的一个重大限制。尽管Outerbridge方案仍然是对软骨病变进行分级的最广泛的分类系统，但它不能指导治疗决策，而且几乎没有证据表明它提供了很多预后信息。为了进一步评估Outerbridge系统，未来的研究应包括更大样本量的验证研究、允许触觉反馈的方法以及对各种关节的评估，以便更准确地评估关节软骨形态。评估软骨损伤的Outerbridge和类似的宏观分类方案未能提供在研究环境中使用所需的信心。该系统已有超过50年的历史，并且在该时间范围内没有整合成像技术的进步。本综述中发现的最佳可靠性比较了关节镜和MR图像。作者建议，Outerbridge系统和任何未来的软骨病变宏观分级系统，都需要结合高级成像(MRI)以实现成功分类系统所需的可靠性。

Outerbridge系统也被证明具有一定的预后价值。Sofu等[19]显示，在关节镜下半月板部分切除术后，III级和IV级膝关节损伤的视觉模拟评分和Lysholm评分更差的结果一致。Bateman等[2]在III级或更高级别病变的患者中，关节镜下肩后盂唇撕裂修复后的功能结果更差。Kemp等[8]还发现，与较低级别的软骨病变相比，在髋关节镜检查中发现股骨髋臼撞击的Outerbridge III级和IV级病变的患者在术后18个月的疼痛和功能更差。

Fig. 1 A-F These intraoperative arthroscopic images demonstrate examples of Outerbridge classification grades: (A) Grade I; (B-C) Grade II; (D) Grade III; (E-F) Grade IV.

图1 A-F这些关节镜术中图像展示了Outerbridge分类等级的示例：(A) I级；(B-C) II级；(D) III级；(E-F) IV级。

Table 1. Studies evaluating the reliability of the Outerbridge classification system of chondral lesions

表1. 评估软骨损伤 Outerbridge 分类系统可靠性的研究

原文

尽管早在20世纪初，就已经对软骨病变进行了直接检查和描述，在Outerbridge于1961年发表他关于该主题的第一篇论文之前，人们对髌骨软骨软化症的病因学并没有很好的了解[15]。在这项初步研究中，他评估了196次内侧半月板切除术期间的髌骨软骨，以更好地了解软骨软化症如何进展以及髌骨的哪些区域主要受到影响。他发现，由于与股骨内侧髁上缘的边缘不断摩擦，软骨软化症最常见于内侧关节面。他还指出，即使在没有症状的情况下，接受开放内侧半月板切除术的患者髌骨软骨软化症的发生率也约为50%。为了更好地了解髌骨软骨软化症的病因，Outerbridge开发了他的分类系统，通过直接可视化来描述不同严重程度的软骨损伤，他在随后的论文中继续使用该系统[15-17]。自从Outerbridge最初为髌骨软骨软化症设计的分类系统被引入以来，它在1989年被改编为包括整个膝关节和推广到其他关节[2, 8, 13]。

除了Outerbridge的方案，还有其他几种描述软骨病变的分类方案。其中包括为膝关节设计的改良Collins[6]和法国关节镜学会(FSA)系统[13]以及为髋关节设计的Beck[3]和Konan[9]分类标准。除了本综述中引用的研究外，关于Collins或法国关节镜学会FSA分类系统的报道很少。Collins的系统在Outerbridge的原始论文之前发表，但与法国关节镜学会FSA系统一起未能获得广泛的普及。Beck方案基于髋关节手术脱位期间的发现，而Konan的分类相当新，只有两项研究评估了其可靠性[1]。尽管提出了其他系统，Outerbridge系统仍然是使用最广泛的系统，这值得对其可靠性进行调查。

目的

1961年最初开发Outerbridge系统时，它被用作纯粹的描述性系统，以更好地了解髌骨软骨软化症的病因。从那时起，它就被用来描述膝关节、髋关节和肩关节的软骨病变[2, 7, 8, 19]。该系统主要用于促进外科医生之间的沟通。尽管尚未证明它可以指导治疗，但一些研究已经使用Outerbridge方案将患者分组以进行临床研究和预后评估[2, 7, 8, 19]。

准确定义（骨软骨损伤）缺伤严重程度对于手术计划和患者教育也很重要。

描述

基于对关节的直接可视化，无论是关节镜还是开放式手术，Outerbridge分类系统被开发为一种简单、易于使用且可重复的关节软骨损伤分级系统。系统将0到IV的等级分配给感兴趣的软骨区域（图1）。Outerbridge分类系统0级表示正常软骨。Outerbridge分类系统I级软骨损伤的特点是软化和肿胀，这通常需要使用探针或其他仪器进行触觉反馈来评估。II级病变描述部分厚度缺损，裂缝直径不超过0.5英寸或达到软骨下骨。III级是直径＞0.5英寸的软骨开裂，区域达到软骨下骨。最严重的是IV级，包括暴露软骨下骨的关节软骨侵蚀[15, 16]。

验证

评估Outerbridge分类系统可靠性的研究要么使用关节镜视频或其他成像方式进行比较。使用关节镜视频研究该方案的可重复性的研究表明，观察者间的可靠性范围从0.28到0.52的κ系数和从0.29到0.8的κ系数的观察者内再现性（表1）[1, 4 , 5, 10, 11]。在这些研究中，Brismar等[4]，Cameron等[5]，Marx等[11]和Amenabar等[1]都使用训练有素的骨外科医生作为观察者，而Lasmar等[10]有两名三年临床经验的住院医师和四名骨外科医生回顾了他们的视频，表明培训水平之间存在明显的观察者内部的可靠性差异（κ = -0.06 对 0.50）。Cameron等[5]还发现，基于两名外科医生在实践中超过5年的经验水平存在可靠性差异，观察者间一致性κ = 0.72，而经验较少的外科医生平均κ = 0.50。这项研究还发现，观察者参与的关节镜评估与这些观察者在关节切开术中使用卡尺直接测量（病变深度和宽度）之间的一致性为68%[5]。

Brismar等研究[4]比较了修改后的Collins和FSA分类系统以及Outerbridge，发现三者之间没有差异，得出的结论是，这些分类中没有一个足够可靠，可用于临床研究。Lasmar等的研究[10] 还比较了Outerbridge和FSA方案，观察者间或观察者内的可靠性之间没有差异。Amenabar等的研究[1]使用Outerbridge和其他两个为髋关节设计的分类系统（Beck [3]和Konan [9]）评估了髋关节的软骨损伤。他们发现系统之间在观察者间可靠性方面没有差异，但Konan的系统在髋部具有出色的观察者间可靠性。与其他方案相比，Outerbridge系统的可靠性较低被认为是特定的软骨损伤模式通常由股骨髋臼撞击和软骨盂交界处的解剖结构引起的结果[1]。

使用影像学作为比较方法的研究（表1）发现观察者间的可靠性范围从一般（κ = 0.35，CT关节造影）到几乎完美（κ = 0.93，MR图像）[14, 18]。在这些研究中，Omoumi等[14]使用放射科医生在没有直接视觉比较的情况下，评估CT关节造影，是唯一一项测试观察者内可靠性的研究(κ = 0.59–0.92)。这项研究发现，经验丰富的放射科医师通常具有更高的观察者内可靠 κ值。Outerbridge方案的最高观察者间可靠性来自Potter等的[18]研究，该研究将膝关节的MR图像与关节镜评估进行了比较。两位放射科医生和三位骨科医生发现了一个几乎完美的(0.93) κ统计量。

（Outerbridge分级系统的）局限性

尽管在过去的几十年里，Outerbridge分类系统在临床和研究环境中得到广泛应用，但仍有一些局限性。对这种分类最常见的批评是它在骨外科医生中的不一致和可重复性差。整体的观察者间可靠性范围仅从弱(κ = 0.28)[1]到中等(κ = 0.52)[5]，而观察者内一致性稍好一些，范围从弱(κ = 0.29) [10]到优良(κ = 0.8) [5]。然而，一些研究提到，审阅者的经验数量会影响系统的可靠性，经验丰富的外科医生具有更好的可靠性[5, 10]。关节镜检查也可能使充分区分2级和3级之间的病变大小以及可视化分配1级所需的柔软度和肿胀变得有些困难[1]。这种可靠性的变化表明，Outerbridge系统的标准需要修改和/或在该方案中实施高级成像(MRI)。目前在Outerbridge分级中使用的粗略宏观方法可能会在外科医生之间传达软骨损伤的严重程度，但文献不支持其用于研究目的的可靠性。

在通过关节镜视频评估Outerbridge分类系统的可靠性的研究中，样本量小有一个普遍的局限性，从6名患者到40名患者不等[1]。此外，验证Outerbridge分类系统可靠性的研究数量相对较少。在使用直接可视化来评估该系统的研究中，只有五项研究测量了观察者间的一致性，只有四项测量了观察者内的一致性。每项评估Outerbridge分类作为参考分级系统的研究都使用膝关节镜检查的视频记录，从而阻止分级外科医生使用触觉反馈作为软骨评估工具。这种触觉反馈尤其重要，因为软骨的粗糙度和软化对于适当的分级很重要[11]。任何关于当前Outerbridge系统可靠性的未来研究都应将触觉反馈纳入方法学，这可能会将研究限制为仅评估关节镜手术或使用尸体膝盖期间的观察者间可靠性。

Outerbridge分类系统也没有提供与疾病预后的明确相关性或治疗指南。只有少数研究显示出对Outerbridge系统的一些预后价值[2, 8, 12, 19]，并且在本综述中没有发现讨论治疗指导的研究。因为这是分类系统应该包含的两个关键特征，所以它们的缺失仍然是该系统的主要限制。

结论

Outerbridge软骨损伤分类系统的观察者间和观察者间一致性从一般到优良不等。这种不一致的可靠性仍然是该系统的一个重大限制。尽管Outerbridge方案仍然是对软骨病变进行分级的最广泛的分类系统，但它不能指导治疗决策，而且几乎没有证据表明它提供了很多预后信息。为了进一步评估Outerbridge的系统，未来的研究应包括更大样本量的验证研究、允许触觉反馈的方法以及对各种关节的评估，以便更准确地评估关节软骨形态。评估软骨损伤的Outerbridge和类似的宏观分类方案未能提供在研究环境中使用所需的信心。该系统已有超过50年的历史，并且在该时间范围内没有整合成像技术的进步。本综述中发现的最佳可靠性比较了关节镜和MR图像。作者建议，Outerbridge系统和任何未来的软骨病变宏观分级系统都需要结合高级成像(MRI)以实现成功分类系统所需的可靠性。

Classifications in Brief: Outerbridge Classification of Chondral Lesions

History

Although cartilage lesions had been directly examined and described as far back as the early 20th century, the etiology of chondromalacia of the patella was not well understood when Outerbridge published his first paper on the subject in 1961 [15]. In this initial study, he evaluated the cartilage of the patella during 196 medial meniscectomies to better understand how chondromalacia progressed and which areas of the patella were primarily affected. He found that chondromalacia was most common on the medial facet as a result of constant friction with a rim on the upper border of the medial femoral condyle. He also noted the incidence of chondromalacia of the patella to be approximately 50% in patients who underwent open medial meniscectomy, even in the absence of symptoms. To better understand the etiology of chondromalacia of the patella, Outerbridge developed his classification system describing varying severity of cartilage lesions by direct visualization, which he continued to use in his subsequent papers [15-17]. Since the introduction of Outerbridge’s classification system originally designed for chondromalacia of the patella, it has been adapted to include the entire knee in 1989 and other joints since then [2, 8, 13].

In addition to Outerbridge’s scheme, there are several other classification schemes describing chondral lesions. These include the modified Collins [6] and French Society of Arthroscopy (FSA) systems [13] designed for the knee as well as Beck’s [3] and Konan’s [9] designed for the hip. Aside from the studies referenced in this review, there is very little reported on the Collins or FSA classification systems. Collins’ system was published before Outerbridge’s original paper but, along with the FSA system, has failed to gain widespread popularity. The Beck scheme is based on findings during surgical dislocation of the hip and Konan’s classification is fairly new with only two studies assessing its reliability [1]. Despite other proposed systems, the Outerbridge system continues to be the most widely used, which warrants investigation into its reliability.

Purpose

In 1961, when the Outerbridge system was originally developed, it was used as a purely descriptive system to better understand the etiology of chondromalacia of the patella. Since then, it has been used to describe cartilage lesions in the knee, hip, and shoulder [2, 7, 8, 19]. The system is largely used to facilitate communication between surgeons. Although it has not been demonstrated to guide treatment, several studies have used the Outerbridge scheme to group patients for clinical research and for prognostic purposes [2, 7, 8, 19].

Accurately defining defect severity is also important for surgical planning and patient education.

Description

Based on direct visualization of the joint, either arthroscopic or open, the Outerbridge classification system was developed to be a simple, easy-to-use, and reproducible grading system of articular cartilage lesions. The system assigns a grade of 0 through IV to the chondral area of interest (Fig.1). Grade 0 signifies normal cartilage. Grade I chondral lesions are characterized by softening and swelling, which often require tactile feedback with a probe or other instrument to assess. A Grade II lesion describes a partial-thickness defect with fissures that do not exceed 0.5 inches in diameter or reach subchondral bone. Grade III is fissuring of the cartilage with a diameter ＞ 0.5 inches with an area reaching subchondral bone. The most severe is Grade IV, which includes erosion of the articular cartilage that exposes subchondral bone [15, 16].

Validation

Studies that have evaluated the reliability of Outerbridge’s classification system either use arthroscopic video or another imaging modality for comparison. The studies that have looked at the reproducibility of the scheme using arthroscopy videos have shown interobserver reliability ranging from a κ coefficient of 0.28 to 0.52 and intraobserver reproducibility ranging from a κ coefficient of 0.29 to 0.8 (Table (Table1)1) [1, 4, 5, 10, 11]. In these studies. Brismar et al. [4], Cameron et al. [5], Marx et al. [11], and Amenabar et al. [1] all used fully trained orthopaedic surgeons for reviewers, whereas Lasmar et al. [10] had two third-year residents along with four orthopaedic surgeons review their videos, demonstrating a clear intraobserver reliability discrepancy between the levels of training (κ = -0.06 versus 0.50). Cameron et al. [5] also found a discrepancy in reliability based on level of experience with the two surgeons in practice for ＞ 5 years having an interobserver agreement of κ = 0.72 and those surgeons with less experience averaging κ = 0.50. This study also found a 68% concordance between the participating observers’ arthroscopic evaluation and direct measurement with calipers (depth and width of lesions) at arthrotomy made by those same observers [5].

Brismar et al.’s study [4] compared the modified Collins and FSA classification systems as well as Outerbridge and found no difference among the three, concluding that none of these classifications was sufficiently reliable for use in clinical research. Lasmar et al.’s study [10] also compared Outerbridge and FSA schemes with no difference between either interobserver or intraobserver reliability. The study by Amenabar et al. [1] evaluated chondral lesions of the hip using Outerbridge and two other classification systems designed for the hip (Beck [3] and Konan [9]). They found no difference between the systems regarding intraobserver reliability, but Konan’s system was noted to have superior interobserver reliability in the hip. Lower reliability with the Outerbridge system compared with other schemes was believed to be a result of the specific chondral damage pattern usually caused by femoroacetabular impingement and the anatomy of the chondrolabral junction [1].

Studies that used imaging as a method of comparison (Table (Table1)1) found an interobserver reliability ranging from fair (κ = 0.35, CT arthrograms) to almost perfect (κ = 0.93, MR images) [14, 18]. Among these studies, Omoumi et al. [14], who used radiologists to evaluate CT arthrograms without a direct visual comparison, was the only study to test intraobserver reliability (κ = 0.59–0.92). This study found that more experienced radiologists in general had higher κ values for intraobserver reliability. The highest interobserver reliability for Outerbridge’s scheme comes from Potter et al.’s [18] study that compared MR images of the knee with an arthroscopic evaluation. The two radiologists and three orthopaedic surgeons found an almost perfect (0.93) κ statistic.

The Outerbridge system has also proven to have some prognostic value. Sofu et al. [19] has shown Grade III and IV knee lesions to have worse visual analog scores and Lysholm scores after arthroscopic partial meniscectomy. Bateman et al. [2] demonstrated worse functional outcomes after arthroscopic shoulder posterior labral tear repairs in patients with Grade III lesions or higher. Kemp et al. [8] also found that patients who had Outerbridge Grade III and IV lesions found during hip arthroscopy for femoroacetabular impingement had worse pain and function at 18 months postsurgery compared with lower grade chondral lesions.

Limitations

Although widely used both in clinical and research settings over the past several decades, the Outerbridge classification system has several limitations. The most common criticism of this classification is its inconsistent and poor reproducibility among orthopaedic surgeons. The overall interobserver reliability ranged only from weak (κ = 0.28) [1] to moderate (κ = 0.52) [5], whereas intraobserver agreement was slightly better ranging from weak (κ = 0.29) [10] to substantial (κ = 0.8) [5]. However, some studies have mentioned that the amount of experience among reviewers affects the reliability of the system with more experienced surgeons having better reliability [5, 10]. Arthroscopy may also make it somewhat difficult to adequately differentiate the size of the lesion between Grades 2 and 3 as well as visualizing the softness and swelling needed to assign a Grade 1 [1]. Such variations in reliability suggest that the criteria for the Outerbridge system needs modification and/or advanced imaging (MRI) implemented into the scheme. The current crude macroscopic method used in Outerbridge grades may work to communicate cartilage lesion severity between surgeons, but the literature does not support its reliability for research purposes.

In the studies evaluating the reliability of the Outerbridge classification system through arthroscopic videos, there was a common limitation of small sample sizes, which ranged from six patients to 40 [1]. Additionally, there has been a relatively small number of studies validating the reliability of the Outerbridge classification system. In studies using direct visualization to assess this system, only five studies measured interobserver agreement and only four measured intraobserver agreement. Each study that evaluated the Outerbridge classification as the reference grading system used video recordings of knee arthroscopy, thus preventing grading surgeons from using tactile feedback as a cartilage assessment tool. This tactile feedback is especially critical because roughness and softening of the cartilage are important for appropriate grading [11]. Any future studies on the present Outerbridge system’s reliability should incorporate tactile feedback into the methodology, which may limit the study to only assessing interobserver reliability during arthroscopic surgery or the use of cadaver knees.

The Outerbridge classification system also does not provide a clear correlation with disease prognosis or a guide to treatment. There are only a few studies that have shown some prognostic value to the Outerbridge system [2, 8, 12, 19] and no studies were found in this review that discuss treatment guidance. Because these are two key features that a classification system should incorporate, their absence remains a major limitation for this system.

Conclusions

The inter- and intraobserver agreement for the Outerbridge classification system for chondral lesions ranges from fair to substantial. This inconsistent reliability remains a substantial limitation of this system. Although the Outerbridge scheme remains the most widespread classification system for grading cartilage lesions, it fails to guide treatment decisions and there is little evidence that it provides much prognostic information. To further evaluate Outerbridge’s system, future research should include validation studies with larger sample sizes, methodology that allows for tactile feedback, and evaluation in a variety of joints for more accurate assessment of articular cartilage morphology. Outerbridge and similar macroscopic classification schemes that evaluate chondral lesions fail to provide the confidence needed for use in research settings. This system is ＞ 50 years old and does not incorporate the advances in imaging technology over that timeframe. The best reliability found in this review compared arthroscopic and MR images. The authors recommend that the Outerbridge system and any future macroscopic grading system of chondral lesions need to incorporate advanced imaging (MRI) to achieve the reliability needed for a successful classification system.

文献出处：Casey Slattery, Christopher Y Kweon. Classifications in Brief: Outerbridge Classification of Chondral Lesions. Review, Clin Orthop Relat Res. 2018 Oct;476(10):2101-2104. doi: 10.1007/s11999.0000000000000255.