ABSTRACT
Objective To analyze the factors that influence screw penetration after plating for proximal humerus fractures of Neer two-or three-part.Methods We reviewed the patients with proximal humerus fracture of Neer types Ⅱ & Ⅲ who had been treated from January 2006 to June 2017.The data were documented regarding gender,age,Neer classification,osteoporosis,surgical procedure,cephalic screw number,type of medial support and screw penetration.They were divided into 2 groups according to the presence or absence of screw penetration.x2 test and independent samples t test were used with software IBM SPSS 22.0.The multivariate logistic regression was used to identify the independent risk factors when there were two or more statistically significant factors.The two-side test was used and significance was set to P ＜ 0.05.Results Altogether 78 patients were included in our analysis,including 27 males (34.62％) and 51 females (65.38％) with an average age of 57.41 years (from 18 to 85 years).Their average follow-up time was 7.7 months (from 3 to 24 months).There were 54 Neer two-part fractures (69.23％) and 24 Neer three-part ones (30.77％).Screw penetration was observed in 18 patients (23.08％) but not in the other 60 ones (76.92％).The x2 test and independent samples t test revealed that screw penetration was significantly associated with gender (P =0.003),osteoporosis (P =0.003) and cephalic screw number (P =0.003) but not with age (P =0.256),Neer classification(P =0.754),surgical procedure((P =0.308) or type of medial support (P =0.186).The multivariate logistic regression revealed that osteoporosis (P =0.027) and cephalic screw number (P =0.026) were independent risk factors for screw penetration.Conclusions After plating for proximal humerus fractures of Neer two-or three-part,the patients with osteoporosis and those receiving more than 5 cephalic screws may face a higher risk of screw penetration than those without osteoporosis and those receiving 4 cephalic screws.