The transphyseal osteotomy for the slipped proximal tibial epiphysis in tibia vara.

This study aimed to describe a novel transphyseal osteotomy (TPO) for acute deformity correction in children with bilateral tibia vara and the atraumatic 'slipped proximal tibial epiphysis' (SPTE) entity. We described the clinical and radiological findings in five children (10 limbs) with tibia vara that were treated with the TPO. The criteria for the SPTE were met in nine (9/10) cases. The surgical technique and short-term results of the TPO are reported. The median age was 9 years (range, 6-9), with obesity (BMI > 95th centile) present in all children. The medial tibial plateau was not significantly depressed (the median angle of depression of the medial plateau measured 30° (range, 20°-32°). The mean medial proximal tibial angle of 33° (range, 8°-71°) was corrected to 82° (range, 77°-86°), the mean anatomic posterior proximal tibial angle of 48° (range, 32°-70°) was corrected to 72° (range, 61°-86°), and the median internal tibial rotation of 45° (range, 20°-50° internal rotation) was corrected to neutral rotation (range, 10° internal-10° external rotation). There were two complications: one case of recurrent deformity and one case of intra-articular extension of the osteotomy. We describe a novel TPO that aims to simultaneously correct all aspects of the deformity, stabilise the physis, and prevent recurrence through epiphysiodesis. Further research is required to determine its efficacy and safety. The atraumatic SPTE appears to represent a specific morphological presentation in tibia vara. Level of evidence: 4.