Radiographic assessment in total knee arthroplasty

Sixty-five total knee arthroplasties were evaluated by the Knee Society Rad iological Evaluation System which was developed to encourage uniform report ing of the results of total knee arthroplasty, All patients were examined b y three independent experienced radiologists 8.9 years after surgery (range , 3-16 years) to analyze the interobserver variability. For measurement of angles, high interobserver correlation was calculated for the prosthetic co mponent angles and the femorotibial shaft angle, The comparison of the mean s indicated no significant differences except for the femorotibial shaft an gle. For measurement of radiolucent lines, interobserver correlation was lo w for all components. The differences of the means were significantly diffe rent for all components. The results of interobserver variability of the pa tellar evaluation revealed high interobserver correlation for the patellar angle and for patellar subluxation and dislocation evaluation. For assessme nt of patellar mediolateral and superoinferior displacement, a low interobs erver correlation was found. For radiographic assessment of total knee arth roplasty, the measurement of angles, including alpha, beta, femorotibial sh aft angle, sagittal femoral and tibial component angle, patellar angle, and patellar subluxation and dislocation evaluation are recommended. The metho d of assessing radiolucent lines should be reconsidered.