title: Results of deformity correction in children with X-linked hereditary hypophosphatemic rickets by external fixation or combined technique.
abstract: BACKGROUND
  The operative procedures to correct multiplanar bone deformities may be indicated for prevention of secondary orthopaedic complications in children with X-linked hereditary hypophosphatemic rickets (XHPR). Different problems related to surgical correction were reported: increased rate of non-union, delayed union, recurrent deformity, deep intramedullary infection, refracture, nerve palsy, and pin tract infection. The aim of this retrospective study was comparison of results of correction in children with XHPR who underwent the treatment with either the Ilizarov device alone or a combined technique: the Ilizarov fixator with flexible intramedullary nailing (FIN) with hydroxyapatite bioactive coating and FIN.
  
  
  METHODS
  We retrospectively analysed 47 cases (children of age under 14 years) affected by XHPR. Simultaneous deformity correction in femur and tibia was performed with the Ilizarov device (group I) or the combined method (group II). This article is based on the results of a historical comparative retrospective study from the same institution.
  
  
  RESULTS
  The duration of external fixation is noted to be shorter applying the combined technique: 124.7 days (group I) vs 87.4 days (group II). In both groups deformity correction was achieved with a proper alignment. Nevertheless, while a child continues to grow during long-term follow-up, deviations of the mechanic axis from the centre of the knee joint have been developing again and values of mLDFA, mMPTA have become pathologic in the most of the cases. In group I location of a newly developed deformity resembled a pre-operative one, whereby both diaphyseal and metaphyseal parts were deformed. In group II in all the cases an apex of deformity was located in distal metadiaphyseal zone of the femur and proximal metadiaphyseal zone of the tibia. It is important to note that all of those in group II were out of the zone of the intramedullary nail.
  
  
  CONCLUSIONS
  Simultaneous correction of femoral and tibial deformities by means of circular external fixators is preferable. Application of a combined osteosynthesis allows to considerably reduce the duration of external fixation and decrease the number of complications. There were no recurrent deformities in parts of bone reinforced by intramedullary nails.
authors.affiliation: Russian Ilizarov Scientific Center for Restorative Traumatology and Orthopaedics, 6, M. Ulyanova Street, 640014, Kurgan, Russian Federation.
authors.forename: Arnold
authors.initials: A
authors.lastname: Popkov
authors.affiliation: Russian Ilizarov Scientific Center for Restorative Traumatology and Orthopaedics, 6, M. Ulyanova Street, 640014, Kurgan, Russian Federation.
authors.forename: Anna
authors.initials: A
authors.lastname: Aranovich
authors.affiliation: Russian Ilizarov Scientific Center for Restorative Traumatology and Orthopaedics, 6, M. Ulyanova Street, 640014, Kurgan, Russian Federation. dpopkov@mail.ru.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Popkov
mesh_terms: D002648:Child; D016267:External Fixators; D053098:Familial Hypophosphatemic Rickets / Q000150:complications / Q000601:surgery*; D005260:Female; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D016268:Internal Fixators; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Deformity correction; Flexible intramedullary nailing; Hydroxyapatite bioactive coating; Ilizarov fixator; X-linked hereditary hypophosphatemic rickets