Risk factors for varus collapse after locking plate fixation of unstable proximal humerus fracture / 中华创伤杂志

ABSTRACT

Objective:To identify potential risk factors of varus collapse after unstable proximal humerus fracture treated with locking plates.Methods:A retrospective case series study was conducted on data of 146 patients with unstable proximal humerus fracture stabilized by locking plates at Xinhua Hospital, Shanghai Jiaotong University School of Medicine from January 2008 through December 2014. These patients were classified into varus collapse group ( n=39) and non-varus collapse group ( n=107) according to the occurrence of varus collapse. The gender, age, bone mineral density, cause of injury, fracture Neer classification, fracture type (varus or valgus), surgical timing, surgical techniques (medial support, cancellous bone graft, suture augmentation), number of humeral head screws and reduction quality were recorded. Potential risk factors were evaluated using univariate analysis and multivariate Logistic regression. The subjective reliability analysis was performed for Neer classification and medial fracture assessments. Results:Varus collapse group had higher ratio of osteoporosis, varus fracture, lack of medial column support, absence of suture augmentation and varus malreductin compared to non-varus collapse group ( P<0.05). While the two groups had no significant differences in gender, age, fracture classification, allogeneic cancellous bone transplantation and number of humeral head screws ( P>0.05). Moreover, the Logistic regression analysis indicated that osteoporosis, varus fracture, lack of medial column support, absence of suture augmentation and varus malreduction were major independent risk factors for varus collapse in proximal humerus fractures ( P<0.05). Among these risk variables, the lack of medial column support showed the strongest correlation of varus collapse after proximal humerus fractures treated with locking plates ( OR=9.62), and varus malreduction was another remarkable risk factor ( OR=8.39). The reliability of Neer classification and medial fracture assessments between interobservers and intraobservers was good. Conclusion:The risk factors for varus collapse after unstable proximal humerus fracture treated with locking plate are osteoporosis, varus fracture, lack of medial column support, absence of suture augmentation and varus malreduction.