Determination of humeral inclination in stemless shoulder arthroplasty using plain radiographs

Orthopedic Reviews

Stefan Landgraeber¹  Manuel Burggraf²  André Busch²  Wegner Alexander²  Sascha Beck²  Theodor Patsalis³  Robert J. Martin⁴ 

[1] Department for Orthopaedics and Orthopaedic Surgery, Saarland University Medical Center and Saarland University Faculty of Medicine, Hamburg;Department of Orthopaedics and Trauma Surgery, University Hospital Essen, University of Duisburg-Essen, Essen;Department of Shoulder, Elbow, Hand and Foot Surgery, St. Josef Hospital, Wuppertal;Faculty of Mathematics, University of Duisburg-Essen, Essen;

关键词: Humeral inclination, humeral neck shaft angle, stemless, total shoulder arthroplasty, reverse shoulder arthroplasty;   

DOI  :  10.4081/or.2019.8194

来源: DOAJ

【 摘 要 】

Plain radiographs of the shoulder are routinely used to assess implant orientation after shoulder arthroplasty. Recently, humeral inclination has come into focus especially in reverse stemless shoulder arthroplasty. But, in X-ray projections not exactly parallel to the base of the humeral component, the humeral inclination angle cannot be determined precisely. Therefore, we established a mathematical algorithm to calculate the humeral neck shaft angle and counterchecked the formula using plain radiographs of a sawbone model containing a humeral head prosthesis. With increasing angles of retroversion, the base of the humeral component forms an ellipse in plain radiographs. Knowing the width and length of the ellipse as well as the inclination angle in a plain radiograph, the exact inclination angle can be determined using the equation reported below. Thus, independent from the viewing angle or angle of retroversion, the inclination angle of a stemless humeral head implant can be estimated with an accuracy of ±1.5-degree deviation. The algorithm proposed may be the basis for further research on the impact of humeral inclination in stemless shoulder arthroplasty.

【 授权许可】

Unknown