Doberstein Scott T, Romeyn Richard L, Reineke David M
University of Wisconsin-La Crosse, La Crosse, WI 54601, USA.
J Athl Train. 2008 Apr-Jun;43(2):190-6. doi: 10.4085/1062-6050-43.2.190.
Various techniques have been described for assessing conditions that cause pain at the patellofemoral (PF) joint. The Clarke sign is one such test, but the diagnostic value of this test in assessing chondromalacia patella is unknown.
To (1) investigate the diagnostic value of the Clarke sign in assessing the presence of chondromalacia patella using arthroscopic examination of the PF joint as the "gold standard," and (2) provide a historical perspective of the Clarke sign as a clinical diagnostic test.
Validation study.
All patients of one of the investigators who had knee pain or injuries unrelated to the patellofemoral joint and were scheduled for arthroscopic surgery were recruited for this study.
A total of 106 otherwise healthy individuals with no history of patellofemoral pain or dysfunction volunteered.
MAIN OUTCOME MEASURE(S): The Clarke sign was performed on the surgical knee by a single investigator in the clinic before surgery. A positive test was indicated by the presence of pain sufficient to prevent the patient from maintaining a quadriceps muscle contraction against manual resistance for longer than 2 seconds. The preoperative result was compared with visual evidence of chondromalacia patella during arthroscopy.
Sensitivity was 0.39, specificity was 0.67, likelihood ratio for a positive test was 1.18, likelihood ratio for a negative test was 0.91, positive predictive value was 0.25, and negative predictive value was 0.80.
Diagnostic validity values for the use of the Clarke sign in assessing chondromalacia patella were unsatisfactory, supporting suggestions that it has poor diagnostic value as a clinical examination technique. Additionally, an extensive search of the available literature for the Clarke sign reveals multiple problems with the test, causing significant confusion for clinicians. Therefore, the use of the Clarke sign as a routine part of a knee examination is not beneficial, and its use should be discontinued.
已有多种技术用于评估引起髌股（PF）关节疼痛的病症。克拉克征就是其中一项检查，但该检查在评估髌骨软骨软化症方面的诊断价值尚不清楚。
（1）以PF关节镜检查为“金标准”，研究克拉克征在评估髌骨软骨软化症存在情况时的诊断价值；（2）提供克拉克征作为临床诊断检查的历史视角。
验证性研究。
招募了其中一位研究者的所有因膝关节疼痛或损伤（与髌股关节无关）而计划接受关节镜手术的患者参与本研究。
共有106名无髌股疼痛或功能障碍病史的健康个体自愿参与。
在诊所手术前，由一名研究者对手术膝关节进行克拉克征检查。若患者因疼痛而无法在手动阻力下保持股四头肌收缩超过2秒，则检查结果为阳性。将术前检查结果与关节镜检查时髌骨软骨软化症的直观证据进行比较。
敏感性为0.39，特异性为0.67，阳性检查似然比为1.18，阴性检查似然比为0.91，阳性预测值为0.25，阴性预测值为0.80。
克拉克征用于评估髌骨软骨软化症的诊断有效性值不令人满意，这支持了其作为临床检查技术诊断价值较差的观点。此外，对现有文献中克拉克征的广泛检索揭示了该检查存在的多个问题，给临床医生造成了严重困扰。因此，将克拉克征作为膝关节检查的常规部分并无益处，应停止使用。
