A clinical study on preoperative valgus stress radiography for evaluating alignment changes of the lower limb after Oxford unicompartmental knee arthroplasty
ZHANG Qi-dong
GUO Wan-shou
YUE Ju-an
LIU Zhao-hui
CHEN Yan
CUI Jian
SUN Shi-long
WANG Wei-guo
Abstract：Objective To investigate the signiifcance and value of preoperative valgus stress radiography for predicting the correction of the varus alignment after Oxford unicompartmental knee arthroplasty ( UKA ).Methods The data of the patients ( 50 knees ) with medial compartmental osteoarthritis ( OA ) who underwent Oxford UKA from September 2013 to June 2014 were retrospectively reviewed. Full-length weight-bearing radiographs of the lower limbs were obtained preoperatively. Weight-bearing anteroposterior ( AP ) radiography and valgus stress radiography in the supine position were also performed preoperatively. The femoro tibial facet angle ( FTFA ) and hip-knee-ankle angle ( HKAA ) were assessed. The characteristics and correlation of the changes of HKAA and FTFA after UKA were analyzed.Results The mean preoperative HKAA was ( 175.7 ± 3.7 ) °, which was increased to ( 178.4 ± 3.6 ) ° postoperatively, with a correction of ( 2.8 ± 2.5 ) ° (P < 0.05 ). The mean FTFA under weight-bearing conditions was ( 2.9 ± 1.8 ) °, which was ( 0.2 ± 1.1 ) ° on valgus stress radiographs, with a correction of ( 2.7 ± 1.5 ) °. A positive correlation existed between the changes of postoperative HKAA and FTFA under valgus stress, and the correlation coefifcient was 0.612 (P < 0.05 ). The mean preoperative and postoperative HKAA were ( 177.5 ± 3.0 ) ° and ( 180.5 ± 3.2 ) ° in the corrected group under valgus stress, with a correction of ( 2.9 ± 2.4 ) °. The mean preoperative and postoperative HKAA were ( 173.5 ± 3.3 ) ° and ( 176.1 ± 2.2 ) ° in the uncorrected group under valgus stress, with a correction of ( 2.6 ± 2.8 ) °.Conclusions A positive correlation exists between the changes of postoperative HKAAand FTFA under valgus stress. Based on the changes of FTFA on preoperative valgus stress radiographs, the alignment changes of the lower limb after Oxford UKA can be predicted. For the patients with preoperative varus deformities which can be corrected with valgus stress radiography, the knee alignment will be more satisfactory after UKA.
Keywords：OsteoarthritiskneeKnee prosthesisArthroplastyreplacementX-ray iflmKnee joint
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 747-751 )