Deformity Correction with External fixator in

							         Deformity Correction with
               External fixator
          in Pseudoachondroplasia


Hae-Ryong Song, Seok-Hyun Lee*, Seung-Woo Suh,
Sameer Desai, Gautam Shetty

Department of Orthopedic Surgery,Korea University
Guro Hospital, Seoul, * Dongguk University International Hospital, Ilsan,
Korea
           Introduction
    Pseudoachondroplasia
 Rhizomelic dwarfism
 Both epiphysis and metaphysis involvement
 Early onset arthritis
 Ligament instability
                                               Windswept deformity
 Os odontoideum with C1-C2 instability
 Cartilage oliogmeric matrix protein (COMP)




                                                 Ligament laxity
             Materials & Methods
 Total 7 patients (4 males, 3 females)
 26 segments (14 tibiae & 12 femora)
 Mean age 24 yrs (7~44)

   Mean follow up 2.5 yrs (2 ~ 5)
                Materials & Methods
   All patients had genu varum
    deformity
   MAD avr 8.1cm (0.5 ~ 11.8)

   Distal femur, proximal tibia :
    varus & procavatum deformity
   Distal tibia : valgus, varus or
    neutral with procavatum
    deformity

    Tibia rotation : 26° int. rotation ~ 43° ext. rotation

    Femoral neck version : 29° anteversion ~ 10° retroversion
                        Operative procedures
     Femur
 hybrid fixator with two rings and a
  proximal arch for gradual correction
 a lateral monofixator (Medixalign,
  Seoul, Korea) for acute correction and
  augmentation with intramedullary
  nails in some cases

     Tibia : Ilizarov’s ring fixator (U & I,
      Seoul, Korea)



    • Postoperative :

    • Gradual distraction started after 7 days

    • 1 mm/day (0.25 mm 6 hourly) : distal femoral and proximal tibial osteotomy site

    • 0.5 mm/day ( 0.25 mm 12 hourly) : distal tibial osteotomy site.
                        Results
   Radiologic
Angular correction       mean 26°(AP) and 16° (Lat.)
MAD correction           mean 7.3 cm (4.3~11.3)
Rotational correction    mean 16° (10~46°)
External fixation time mean 3.5 months (1.5~7.5)
(EFT)
Amount of lengthening mean 2.3 cm (1~4.2)
External fixation index mean 55 days/cm (20~120)
                         Results
   Complications
   9 major & 12 minor in 24/26 segments




   Recurrent deformity, delayed consolidation,
    refracture, pin site infection, knee stiffness, residual
    ligament laxity, compartment syndrome
             Functional results
Preoperatively

3   pts               <50m pain-free walking
2   pts               100m
1   pt                500 m
1   pt (knee brace)   1 km

Postoperatively

2   pts               0.1km pain-free walking
3   pts               1~3 km
1   pt (knee brace)   3 km
1   pt                unchanged
       Results




       Radiologic   Clinical
        results     results
Good       5           4
Fair      12           5
Poor       9           5
                       Conclusions
   Recurrent deformity in children and delayed consolidation in
    adult contributed to radiographic poor results.

   Recurrent varus deformity of the knee in children was
    inevitable because there was asymmetric epiphyseal growth.

   Therefore, patients need to be well informed about the
    possibility of recurrent or residual deformity during growth
    before primary surgery.