Figure 2From: Prophylactic titanium elastic nailing (TEN) following femoral lengthening (Lengthening then rodding) with one or two nails reduces the risk for secondary interventions after regenerate fractures: a cohort study in monolateral vs. bilateral lengthening procedures The types of callus fracture or lengthening-associated fractures in the Simpson and Kenwright classification [[15]: Ia, bulging fracture in the regenerate; Ib, complete fracture in the regenerate; II, fracture at the bone–callus junction (host–regenerate junction); III, fracture in the lengthened leg outside the regenerate zone (pin site); IV, fracture in the lengthened bone outside the regenerate zone (not at a pin. Back to article page