Posteromedial bowing of the tibia: a benign condition or a case for limb reconstruction?

Purpose: To review the initial deformity and subsequent remodelling in posteromedial bowing of the tibia and the outcome of limb reconstruction in this condition.

Patients and Methods: In all, 38 patients with posteromedial bowing of the tibia presenting between 2000 and 2016 were identified. Mean follow-up from presentation was 78 months. A total of 17 patients underwent lengthening and deformity correction surgery, whilst three further patients are awaiting lengthening and deformity correction procedures.

Results: The greatest correction of deformity occurred in the first year of life, but after the age of four years, remodelling was limited. The absolute leg-length discrepancy (LLD) increased throughout growth with a mean 14.3% discrepancy in tibial length. In the lengthening group, mean length gained per episode was 45 mm (35 to 60). Mean duration in frame was 192 days, with a mean healing index of 42.4 days/cm. Significantly higher rates of recurrence in LLD were seen in those undergoing lengthening under the age of ten years (p = 0.046). Four contralateral epiphysiodeses were also performed.

Conclusion: Posteromedial bowing of the tibia improves spontaneously during the first years of life, but in 20/38 (53%) patients, limb reconstruction was indicated for significant residual deformity and/or worsening LLD. For larger discrepancies and persistent deformity, limb reconstruction with a hexapod external fixator should be considered as part of the treatment options.

Level of evidence: Level IV (Case series).