ABSTRACT
BACKGROUND: Non-surgical treatment for impacted femoral neck fractures is a strategy rarely used at present. Hollow screw internal fixation is the main treatment for impacted femoral neck fractures. Studies on impacted femoral neck fractures so far have focused on treatment patterns and risk factors affecting internal fixation failure, but the effect of initial degree of deformity of impacted femoral neck fractures on postoperative femoral neck shortening was not studied. OBJECTIVE: To analyze the relationship between the degree of shortening and initial deformity of impacted femoral neck fractures after hollow screw fixation in patients under 65 years of age and the effect of femoral neck shortening on hip function. METHODS: Fifty-three impacted femoral neck fractures patients with complete medical records were included, and treated with three hollow screws for internal fixation. The patients were followed up for 12-24 months. Hip Harris score was used to evaluate the recovery of function. The posterior inclination angle, valgus angle, and Pauwels angle of the affected femoral head were measured by X-ray examination of pelvis and hip joint before treatment. X-ray films of pelvis were taken at the last follow-up to calculate the percentage of joint-coarsal distance decrease representing the degree of femoral neck shortening. Not less than 30% is significantly shortened (SFNS) and less than 30% is not significantly shortened (NSFNS). The related factors of neck shortening and the effect on hip function were analyzed. RESULTS AND CONCLUSION: (1) All 53 patients healed without adverse events such as femoral head necrosis. Seven cases (13.2%) had obvious neck shortening. (2) Independent-sample t-test found that neck shortening was associated with valgus angle (P=0.000), posterior dip angle (P=0.001) and body mass index (P=0.001). Logistic regression analysis found that valgus angle was a significant predictor of neck shortening (P=0.041). (3) The hip Harris score decreased with the increase of femoral neck shortening. The hip Harris scores were (82.57±5.12) and (94.15±4.03) in the SFNS group and NSFNS group, respectively, with significant difference. (4) It is indicated that the degree of valgus deformity is an independent risk factor for neck shortening in impacted femoral neck fractures, and femoral neck shortening is associated with hip function.