Guided growth for angular correction in children: a comparison of two tension band plate designs

Guided growth for angular correction in children: a comparison of two tension band plate designs

Journal of Pediatric Orthopedics B, 2018 – Dr. Muayad Kadhim et al.

This retrospective cohort study examined 20 patients (48 physes), 11 boys and nine girls, who were treated with hingeplate or eight-plate. The mean age of the patients at surgery was 11.9±2.6 years. The mean follow-up duration was 13±2.7months. The radiographic measurement of both distal femoral and proximal tibial deformity showed significant correction,with no difference between the hinge-plate and the eight-plate. Both screw divergence angle and the hinge angle showedsignificant changes at the last follow-up. The deformity correction of the distal femoral physis was quicker than theproximal tibial physis. The rate of mechanical femoral-tibial angle correction was 0.97°/month if both femoral and tibialphyses were treated.

Discussion:

Complications described in the literature during guided growth treatment are largely related to hardware failure or migration [10,22,23]. Mechanical failure of tension band plates occurs most commonly when the metaphyseal screw breaks at the site of insertion into the bone [24]. This was reported by Shin et al. [21] in their comparison study. We also reported metaphyseal screw breakage in one patient treated with an eight-plate. This screw breakage is likely because of ‘three-point bending forces’ caused by poor plate fitting onto the bone [23]. Plate bending to contour the plate to the bone surface has been suggested to lower the stress at the screw insertion point and therefore the risk of screw failure [23]. In addition, solid screws were recommended instead of cannulated screws, particularly in obese patients [5,23,25]. Insertion of solid screws can be performed safely using fluoroscopy guidance to avoid physis injury [26]. Longer metaphyseal screws were also recommended to avoid screw pullout [15]. The combination of plate-bending ability through the hinge and the use of solid screws in the H-plate construct should theoretically decrease the risk of screw failure [24]. The hinge allows continued correction after the screw head/plate interface has reached maximal excursion.