Reply To the editor

Re: “Efficacy and complications after delayed fixation of femoral neck fractures in children”, J Orthopaedic Surgery, published 2020, 28(1). DOI:10.1177/2309499019889682

Dear Editor,

I am very grateful to the author of the letter for the details of my article and the emphasis on matters needing attention to help further clarify the focus of delayed reduction of femoral neck fractures in children.

“Rockwood & Wilkin’s fractures in children” suggest ¹

Type I fracture requires reduction or moves significantly during reduction or casting maneuvers, then internal fixation is mandatory. Two-millimeter smooth K-wires are inserted percutaneously to cross the physis. We recommend two or three wires. Type II and III fractures should be stabilized with 4- to 4.5-mm cannulated screws in small children up to age 8. After the age of 8, fixation with 6.5-mm cannulated screws is appropriate. Two or three appropriately sized screws should be used, depending on the size of the child’s femoral neck. For Type IV fracture, a pediatric hip screw or pediatric hip locking plate provides the most rigid internal fixation for this purpose. Smaller hip screw devices have made ORIF an option in children younger than 10 years.

In our study, in these cases, only one patient with Delbet Type I (1 year old) was treated with open reduction and two Kirschner wires for internal fixation. The other fractures (type I, II and III) were stabilized with two 4.5–6.5-mm cannulated screws, depending on the size of the children’s femoral neck.

Literature suggests ¹

A hip spica cast must be used to supplement internal fixation in all patients who are younger than 10 years. For older patients, if the stability of the fracture is questionable or if the child’s compliance is doubtful, the surgeon should not hesitate to apply a hip spica cast. The quality of reduction and the stability of the fixation have a direct impact on the occurrence of nonunion.

Patients go home a few days after operation. Without hip spica cast, the children will stand, walk, and even run, not really achieve weight-free recovery. We also encountered several cases in which the children removed cast by themselves and walked, resulting in chondrolysis, premature closure of epiphysis, femoral head necrosis, and other serious complications. Therefore, we used hip spica for about 2 months after operation. When the radiography showed the fracture line began to heal, the cast was removed and the patient began to bedside exercise, nonweight-bearing walking, and weight-bearing walking step by step.

Hip varus, valgus, nonunion, chondrolysis, avascular necrosis, unequal length of lower limbs, and short neck deformity are complications. However, no cases of coxa varus, coxa valgus, premature epiphyseal closure, nonunion, or chondrolysis were found in the follow-up of children treated according to the standards of our department. There were a few cases of avascular necrosis, unequal length of lower limbs, and short neck deformity. Probably anatomical reduction, rigid internal fixation, and hip cast help decreasing these complications, however, few cases and short follow-up time may lead deviation.

For femoral neck fracture reduction, we agree with the requirements of the letter, “is aim of achieving anatomical reduction and not the acceptable reduction.” In our experience, both closed reduction and open reduction require anatomical reduction for the first. We try to use closed reduction if possible. If tried for three times and failed to achieve anatomical reduction, then we change to open reduction to achieve anatomical reduction under direct vision.

Chunxing Wu , Bo Ning, Ping Xu, Jun Song and Dahui Wang Department of Pediatric Orthopedics, Children’s Hospital of Fudan University, Shanghai, China Corresponding author: [e-mail]