4种因素可预测将来膝关节置换可能性

费城——马里兰大学风湿与临床免疫学系主任Marc C. Hochberg博士在世界骨关节炎大会上报告称，了解患者的年龄、性别、生活质量评分和放射学膝骨关节炎严重程度，有助于预测在接下来5年内接受全膝关节成形术(TKA)的几率。本次大会是由国际骨关节炎研究学会(ORSI)主办的。

尽管美国的TKA负担相当重，但此前仅有少量研究分析了社区人群中TKA的预测因素。据估计，目前有400万接受TKA后仍健在的美国人，而且在被诊断为膝骨关节炎(OA)的成年患者中超过一半将接受TKA(J. Bone Joint Surg. Am. 2013;95:385-92)。

在本项分析中，Hochberg博士及其同事从骨关节炎首创研究中获取了6,406例症状性、放射学膝骨关节炎患者或该病高危者的4年随访数据。第5年随访仅采用问卷调查。放射学膝骨关节炎Kellgren-Lawrence(KL)严重度分级为0、1、2、3和4的右膝比例分别为36%、18%、28%、14%和3.5%，左膝比例分别为38%、18%、26%、14.4%和3.3%。

Marc Hochberg博士

略多于半数的受试者为女性(58.4%)，平均体重指数(BMI)为28.7 kg/m²，平均年龄为62.7岁，平均西安大略与麦克马斯特大学骨关节炎指数(WOMAC)疼痛评分为2.47(满分为20)，平均WOMAC功能评分为8.33(满分为68)，平均膝损伤与骨关节炎结局评分(KOOS，反映生活质量)为66.10(满分为100)。

在5年随访期间，共实施了91次右侧TKA和102次左侧TKA。考虑年龄、性别和BMI的受试者操作特征曲线下面积(AUC)，右膝为0.64，左膝为0.67。

最佳的TKA预测模型包含年龄、性别、BMI和KOOS生活质量评分，该模型对右膝和左膝的AUC分别提高至0.78和0.80。如果再加入WOMAC疼痛评分，对右膝和左膝的AUC分别为0.79和0.80，并不能明显提高预测价值。如果将KL严重度分级加入该模型，对右膝和左膝的AUC分别增至0.89和0.91。敏感性分析显示，加用其他基线变量并不能进一步提高预测价值。

这项研究的局限性包括，TKA例数相对较少，多数患者基线时KL分级为2，未进行比例风险分析，而且未考虑双侧膝盖之间的关联或自变量随时间的改变。

既往一项前瞻性研究显示，接受手术的意愿是首次接受髋或膝全关节置换术(TJR)时间的最强预测因素(Arthritis Rheum. 2006;54:3212-20)。OARSI国际工作组(Hochberg博士是该工作组成员)曾报告称，被建议接受髋或膝TJR的患者的疼痛和残疾程度更高(Osteoarthritis Cartilage 2011;19:147-54)。但该工作组未能确定区分愿意和不愿接受手术的患者的疼痛、残疾切点。

骨关节炎首创研究获得了国立卫生研究院的资助。Hochberg博士报告称担任了Allergan、Bioiberica、Iroko、默克和辉瑞的顾问，并且是礼来和默克的科学/医学顾问委员会成员。

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By: PATRICE WENDLING, Internal Medicine News Digital Network

PHILADELPHIA – Knowledge of a patient’s age, gender, quality of life score, and radiographic knee osteoarthritis severity helps predict the odds of a patient undergoing total knee arthroplasty in the next 5 years.

Few studies have looked at the predictors of total knee arthroplasty (TKA) in community-based cohorts, despite the heavy burden of TKA in the United States, said Dr. Marc C. Hochberg, head of rheumatology and clinical immunology, University of Maryland, Baltimore. An estimated 4 million Americans already live with TKA, and more than half of adults diagnosed with knee osteoarthritis (OA) will undergo TKA (J. Bone Joint Surg. Am. 2013;95:385-92).

For the current analysis, Dr. Hochberg and his associates obtained 48 months of annual clinical follow-up data on 6,406 patients in the Osteoarthritis Initiative who had symptomatic, radiographic knee OA or who were at risk for the condition. Follow-up at 60 months involved only questionnaires. Consensus readings of knee radiographs were used for the analysis, along with knee-specific multiple variable regression models. The best models were selected based on Chi-square values and area under the receiver operating characteristic curve (AUC). Radiographic knee OA Kellgren-Lawrence (KL) severity grade 0, 1, 2, 3, and 4 was present in the right knee of 36%, 18%, 28%, 14%, and 3.5% of patients and in the left knee of 38%, 18%, 26%, 14.4%, and 3.3% of patients.
 
A little more than half of participants were women (58.4%), mean body mass index was 28.7 kg/m2, mean Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score was 2.47 (0-20 scale), mean WOMAC function score was 8.33 (0-68 scale), and mean Knee injury and Osteoarthritis Outcome Score (KOOS) (quality of life) was 66.10 (0-100 scale). Their average age was 62.7, he said at the World Congress on Osteoarthritis, sponsored by the Osteoarthritis Research Society International.

During the 60 months of follow-up, there were 91 right and 102 left TKAs. The AUC for age, sex, and BMI was 0.64 for the right knee and 0.67 for the left knee.

The best TKA prediction models included age, sex, BMI, and KOOS quality-of-life score, improving the AUC to 0.78 for the right knee and 0.80 for the left knee, Dr. Hochberg said. Addition of the WOMAC pain score was associated with a marginal, but significant improvement in the AUC (0.79 and 0.80, respectively). When KL grade was added to these models, the AUC reached 0.89 and 0.91 for the right and left knees, respectively, he said. Sensitivity analyses failed to demonstrate additional effects of other baseline variables when added.

Limitations of the study included the relatively few TKAs, that most patients had KL grade 2 at baseline, proportional hazards analyses were not used, and the study did not consider a correlation between knees or the change in independent variables over time, he said.

In a prospective Canadian study, willingness to undergo surgery was the strongest predictor of the time to first hip or knee total joint replacement (TJR) (Arthritis Rheum. 2006;54:3212-20), while an international OARSI Task Force reported that pain and disability was higher in patients recommended for hip or knee TJR (Osteoarthritis Cartilage 2011;19:147-54). The Task Force, which included Dr. Hochberg, could not, however, identify cut points for pain and disability that would discriminate between those who did or did not get the nod for surgery.

The Osteoarthritis Initiative is sponsored by the National Institutes of Health. Dr. Hochberg reported serving as a consultant for Allergan, Bioiberica, Iroko, Merck, and Pfizer, and as a scientific/medical advisory board member for Eli Lilly and Merck.