全膝关节置换术髌骨高度测量方法间差异研究

Interobserver variation in the measurement of patellar height after total knee arthroplasty

[目的]研究全膝关节置换手术前后髌骨高度4种测量方法的准确性和可重现性，这4种方法是Black—burne—Peel指数、Caton—Desehamps指数、InsaLL-Salvati指数和改良的Insall-Salvati指数。[方法]使用这4种方法对44例（45个膝）全膝关节置换的病人术前和术后侧位x线片进行2组独立的髌骨高度测量。2名实验者在特定的条件下以独立的方式分别进行了720个数据的测量。[结果]术前使用Insall-Salvati指数和改良的Insall—Salvati指数同使用Blackburne—Peel和Caton—Deschamps指数之间存在较大的差异。由于BlackbumePeel和Caton Deschamps指数以假体关节线为参照，术后观察者间差异明显减小。[结论]真实的髌骨高度测量和真实低位髌骨或高位髌骨的确认，需使用Insall—Salvati指数和改良的Insall-Salvati指数；Blackbume—Peel指数和Caton-Deschamps指数用来评估与关节面相关的髌骨高度和明确假性低位髌骨十分准确。

[ Objeetive] To assess the reproducibility and accuracy of four ratios used to measure patellar height, named the Blackburne-Peel, Caton Desehamps, Insall-Salvati and modified Insall-Salvati, before and after totalknee arthroplasty. [ Methods] The patellar height was measured, by means of the four ratios, on the pre-and post-operative lateral radiographs of 44 patients （45 knees） who had undergone total knee arthroplasty. Two independent observers measured the films sequentially, in identical conditions, totally 720 measurements per observer. [ Results] Before operation there was greater interobserver variation using either the Insall-Salvati or modified Insall-Salvati ratios than that when using the Caton-Desehamps or Blaekburne- Peel methods. This was due to difficulty in identifying the insertion of the patellar tendon. Before operation, there was a minimal difference in reliability between these methods. After operation the interobserver difference was greatly reduced using both the Caton-Desehamps and Blackburne-Peel methods, which used the prosthetic joint line, compared with the Insall-Salvati and modified Insall-Salvati, which refered to the insertion of the pateUar tendon. [ Condusion] The theoretical advantage of using the Insall-Salvati and modified Insall-Salvati ratios in measuring true patellar height after total knee arthroplasty needs to be balanced against their significant interobserver variability and inferior reliability when compared with other ratios.