Initial Evaluation on Subsidence of Cemented Collarless Polished Tapered Stem Applied to the Patients with Narrow Femoral Medullar Canal
Katsuyuki Dairaku*, 1, Masaji Ishii2, Shinji Kobayashi1, Hiroyuki Kawaji2, Kan Sasaki1, Yuya Takakubo1, Michiaki Takagi1
Identifiers and Pagination:Year: 2010
First Page: 147
Last Page: 151
Publisher Id: TOORTHJ-4-147
Article History:Received Date: 18/12/2009
Revision Received Date: 14/1/2010
Acceptance Date: 9/2/2010
Electronic publication date: 16/3/2010
Collection year: 2010
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
The geometry of the proximal femur is one of the important factors for choosing the suitable stem. We have been applied cemented collarless polished tapered (CPT) stem to the patients with small femur. Radiographic evaluation was performed to access the clinical feature of the stem in early stage of the follow-up.
One hundred total hip arthroplasties with CPT system were performed between October 2004 to February 2006. This study focused on the 53 cases to whom size 1 or smaller sized stem were implanted, and its post-operative period was 41 months (30-46 months). Morphologic classification of preoperative proximal femur, stem alignment, thickness of the cement mantle, cementing technique, subsidence of the stem, improvement in the bone-cement interface, and stress shielding were assessed.
The size of the inserted stem was X-SMALL in one case, SMALL in two cases, SIZE 0 in 12 cases, and SIZE 1 in 38 cases. Canal shape of proximal femur was stovepipe type in five cases, normal type in 43 cases, and champagne-flute type in five cases. There was no subsidence in eight cases. 44 stems subsided within 1 mm, one stem subsided 1 to 2 mm, and no stem subsided over 2 mm. In 39 of 45 cases, subsidence was appeared within six months after operation. Marked progressive and excessive subsidence was not seen after the two years of follow-up.
Short term radiographic results of THA with CPT stem to small femur were satisfactory with less unfavorable radiographic findings, which imply contribution to longer survivorship of the stem.