Invalid Comparison Between Methods of Epiphysiodesis
In their manuscript, Gaumetou et al1 attempted, to assess the efficiency of 2 diametrically opposite methods of epiphysiodesis for anisomelia.
It is clear that they did not grasp the fundamental difference between the techniques that invalidates their conclusion that 8-plates should not be used to treat limb length discrepancy.
The so called “standard methods” of epiphysiodesis that they describe are either ablative (Phemister/percutaneous drilling) or compressive (Blount staples/transphyseal screws=percutaneous epiphysiodesis using transphyseal screws). This is analogous to slamming the gearshift into park while driving a vehicle. The goal is to achieve immediate, and often permanent growth arrest, without any lag period. Therefore these methods require precise determination of both the skeletal age of the patient and the estimated final discrepancy at maturity. Such methods lend themselves to measurement of efficiency at designated benchmarks such as 6 and 18 months.
In contradistinction, the goal of guided growth with a pair of 2-hole tension band plates is to produce growth deceleration, not growth arrest. Thus, it is more like applying the brakes in a moving vehicle. Anticipating a lag period, the optimal timing is at least 1 year sooner than with “standard methods.” Therefore, the 6- and 18-month benchmarks are not relevant. Guided growth obviates the need for precise determination of skeletal age and growth remaining. Divergent screws are recommended at the outset, to reduce the lag time (Fig. 1). Because this technique is reversible, it may safely be accomplished in younger patients (even as young as age 3 for gigantism). After 2 years, the metaphyseal screws are removed and, following a reprieve of 6 months, reinserted, as indicated (Fig. 2). Biannual follow-up until maturity is required to make adjustments in the event of axial deviation. This method, which requires patience and understanding, is ultimately a very successful means to address anisomelia.
In the “Limitations” section, the authors incorrectly claimed that their series is “larger than previously published reports of 8-plate use in LLD limb length discrepancy.” They failed to cite the larger series that predated theirs by 3 years.