Part 1. Review and meta‐analysis of studies on modulation of longitudinal bone growth and growth plate activity: A macro‐scale perspective

Abstract

Growth modulation is an emerging method for treatment of angular skeletal deformities such as adolescent idiopathic scoliosis (AIS). The Hueter-Volkmann law, by which growth is stimulated in tension and inhibited in compression, is widely understood, and applied in current growth-modulating interventions such as anterior vertebral body tethering (AVBT) for AIS. However, without quantification of the growth rate effects of tension or compression, the possibility of under-or overcorrection exists. A definitive mechanical growth modulation relationship relating to treatment of such skeletal deformities is yet to exist, and the mechanisms by which growth rate is regulated and altered are not fully defined. Review of current literature demonstrates that longitudinal (i.e., lengthwise) growth rate in multiple animal models depend on load magnitude, anatomical location, and species. Additionally, alterations in growth plate morphology and viability vary by loading parameters such as magnitude, frequency, and whether the load was applied persistently or intermittently. The aggregate findings of the reviewed studies will assist in work towards increasingly precise and clinically successful growth modulation methods. Part 1 of this review focuses on the effects of mechanical loading, species, age, and anatomical location on the macro-scale alterations in longitudinal bone growth, as well as factors that affect growth plate material properties. Part 2 considers the effects on micro-scale alterations in growth plate morphology such as zone heights and proportions, chondrocyte viability, and related gene and protein expression.

A numerical study towards shape memory alloys application in orthotic management of pediatric knee lateral deviations

“…Its use could hypothetically be a significant improvement for current orthotic treatments, somehow comparable with the introduction of NiTi arcs in orthodontics 13 , 39 . The precise quantification of the forces to be applied is a key point for this 18 . These should be as high as possible to accelerate correction, but at the same time must not injury the patient.…”

“…In the case of growth pathologies, orthoses efficacy is typically assessed after treatment periods of around 30 months 6 . This makes the precise quantification of applied forces effects to be of upmost importance for their design 18 . The mechanical loads exerted by any orthotic device should be as large as possible to reduce the treatment duration, but at the same time, should not injury or excessively discomfort the patient.…”

Minimum 3-year experience with vertebral body tethering for treating scoliosis: A systematic review and single-arm meta-analysis

“…Therefore, the poor correction or even deterioration after VBT treatment may be attributed to the existence of the CGFRC. 52 Appropriate VBT may result in ineffective correction or overcorrection of scoliosis. To implement an effective growth regulation intervention, it is necessary to understand the relationship between mechanical tension and compression and the resultant change in vertebral body growth behavior to achieve the desired corrective effect.…”

What’s New in Limb Lengthening and Deformity Correction

“…Macro‐scale changes in longitudinal bone growth resulting from mechanical loading relied on load magnitude, anatomical location, and species. From the micro-scale perspective, understanding the gene and protein expressions altered by mechanical loading may be an important step toward progressively less invasive correction of skeletal deformity, including methods other than mechanical modulation 66,67 .…”