Plate vs. Screw for Guided Growth in Coronal Knee Deformities

Genu varum and genu valgum are common lower limb deformities observed in children and adolescents. These conditions often require guided growth techniques for correction. One widely accepted approach for modulating growth and gradually correcting these deformities is temporary Hemi-epiphysiodesis. The two most commonly used techniques for this purpose are the Tension Band Plate (TBP) e.g. Eight-Plate and Percutaneous Epiphysiodesis using Transphyseal Screws (PETS). While both methods have proven effective, there remains ongoing debate about their relative efficacy, safety, and long-term outcomes.

The TBP technique, introduced as a less invasive method of guided growth, involves placing a non-locking plate and screws across the growth plate on one side allowing controlled correction without permanent damage to the physis.

Studies have demonstrated its effectiveness in treating angular deformities with a lower risk of growth plate closure, but concerns remain regarding implant migration, breakage, and rebound deformity post-removal. Conversely, PETS offers a minimally invasive alternative where transphyseal screws modulate growth without requiring plate fixation. Some studies suggest PETS may provide more rapid correction with fewer complications, while others highlight the potential risk of premature physeal closure, which could lead to limb length discrepancies.

Despite the widespread use of both techniques, there is limited high-quality comparative data to determine the superior method in terms of correction rate, complication profile, and long-term functional outcomes. A randomized controlled study comparing TBP and PETS is essential to establish evidence-based guidelines, optimize patient outcomes, and refine surgical decision-making in the management of genu varum and genu valgum. Our novel introduction of the Bone-Length Adjusted Correction Rate as a new criterion will further enhance the measurement of effectiveness for these interventions.

Inclusion criteria

• Children and adolescents beyond the age of physiological varus/valgus correction (i.e., typically ≥4 years for genu varum and ≥7 years for genu valgum) with Mechanical Axis Deviation (MAD) in lower limbs and abnormal joint orientation angles, in the coronal plane either femoral or tibial.
• Open physis (growth plate) on radiographs and at least one year of growth remaining before age of skeletal maturity (typically ≤14 years in females, ≤16 years in males).

Exclusion criteria

• Sick Physis as in Blount's disease stages III-V or any partial or total physeal arrest caused by trauma, inflammation or neoplasia.
• Uncorrectable systemic disorders affecting bone growth and alignment, including but not limited to:

i- Severe metabolic disorders (e.g., advanced rickets, hypophosphatasia, mucopolysaccharidoses) ii- Uncontrolled endocrine disorders (e.g., untreated hypothyroidism, growth hormone abnormalities) iii- Severe connective tissue disorders (e.g., osteogenesis imperfecta, advanced Ehlers-Danlos syndrome) iv- Chronic inflammatory or hematologic conditions that impair bone growth (e.g., severe juvenile idiopathic arthritis, advanced sickle cell disease)