A comparative study between double-threaded compression screws and cannulated lag screws for fixation of Garden type Ⅰ / Ⅱ femoral neck fractures / 中华骨科杂志

ABSTRACT

Objective To compare the results between double-threaded compression screws and cannulated lag screws for Garden type Ⅰ/Ⅱ femoral neck fractures.Methods Data of 56 patients with Garden type Ⅰ/Ⅱ femoral neck fractures who were treated with internal fixation from July 2012 to March 2016 were retrospectively analyzed.According to different fixation,the patients were divided into two groupsdouble-threaded screws group (group A) including 27 cases (7 males and 20 females,with an average age of 55.5±10.0 years,14 cases Garden type Ⅰ and 13 cases Garden type Ⅱ,the proportion of osteoporosis 10/27;And lag screws group (group B) including 29 cases (8 males and 21 females,with an average age of 57.2±9.5 years,11 cases Garden type Ⅰ and 18 cases Garden type Ⅱ,the proportion of osteoporosis 15/29.The 2 groups were compared with respect to bony fusion time,nonunion,avascular necrosis of femoral head,shortening of femoral neck and Harris Hip Score.Results The average follow-up time was 20.3±8.7 m in Group A and 24.5±7.9 m in Group B.The average bony fusion time was 5.3±0.6 m in Group A and 4.1±0.8 m in Group B,and there was significant difference between the groups (t=5.758,P=0.00).1 avascular necrosis of femoral head was found in both groups.In group A,there were 3 cases of bone nonunion (11.1％,3/27).There were one bone nonunion (3.4％,1/29) case in group B,with no statistically significant difference between groups.Shortening of femoral neck occurred in both groups,the average horizontal shortening was 5.8±2.9 mm and vertical shortening 7.0±3.4 mm in Group A,which were lower than group B (8.2±3.1 mm,9.4±3.6 mm),and the differences showed statistically significant (t=-2.94,P=0.005;t=-2.48,P=0.016).In group A,the average Harris Hip score was 88.2±8.3,while that in group B was 89.9±7.2.There was no statistically significant difference between two groups.Conclusion It seems to us that in the treatment of Garden type Ⅰ/Ⅱ femoral neck fractures,doublethreaded compression screws fixation could reduce femoral neck shortening,but there is no difference on functional outcome compared to cannulated lag screws fixation.On the contrary,double-threaded compression screws fixation is not conducive to fracture healing due to lack of sliding compression.