Overgrowth of the femoral neck after hip fractures in children.
BACKGROUND
Overgrowth after pediatric femoral shaft fractures is well documented; however, overgrowth of the femoral neck after hip fractures has not been especially reported previously. The purpose of this study was to evaluate the incidence and characteristics of femoral neck overgrowth after hip fractures in children.


METHODS
From January 1990 to December 2012, there were 30 consecutive patients with pediatric hip fractures. We retrospectively reviewed the medical record of all the patients, including age at injury, gender, injury mechanism, fracture type, methods of treatment, time to bony union, and complications. The functional outcome was evaluated by Ratliff's criteria. The radiography of the pelvis was performed in controlled positions of abduction and external rotation. The length of the femoral neck was measured by two observers. The overgrowth of the femoral neck was defined as lengthening more than 3 mm in comparison with the uninjured hip.


RESULTS
At a mean follow-up of 4.9 years (range 2-8 years), 12 patients (40 %) had an overgrowth of the femoral neck. The average overgrowth of the femoral neck was 6.2 mm (range 3.2-8.5 mm). The patients with femoral neck overgrowth were younger (p = 0.0002), have lower rate of avascular necrosis of the femoral head (p = 0.0006), and have better functional outcome (p = 0.0026).


CONCLUSIONS
Our results provide evidence that overgrowth of the femoral neck following hip fractures may occur in children and the overgrowth phenomenon in the femoral neck was a predictor of good outcomes after treatment.
Department of Orthopaedic Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, No. 123, Ta Pei Road, Niao Sung District, Kaohsiung City, 83301, Taiwan.
Feng-Chih
FC
Kuo
Department of Orthopaedic Surgery, China Medical University Hospital, 2 Yude Road, Taichung City, 40447, Taiwan.
Shu-Jui
SJ
Kuo
Department of Orthopaedic Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, No. 123, Ta Pei Road, Niao Sung District, Kaohsiung City, 83301, Taiwan. kojy@adm.cgmh.org.tw.|Department of Orthopaedic Surgery, Xiamen Chang Gung Hospital, No. 123, Xiafei Road, Haicang District, Xiamen, Fujian, China. kojy@adm.cgmh.org.tw.
Jih-Yang
JY
Ko
D002648:Child; D002675:Child, Preschool; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000254:growth & development*; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000379:methods*; D017102:Fracture Healing; D006801:Humans; D007223:Infant; D008297:Male; D011379:Prognosis; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
Complications; Femoral neck fracture; Overgrowth; Pediatric