Outcomes of the Evans Calcaneal Lengthening Based on Bone Grafting Material
Condition: Cerebral Palsy; Pes Planus
MeSH terms: Flatfoot; Cerebral Palsy
Study type: Observational

Summary: 
      The Evans calcaneal lengthening is a common surgical correction used for children with
      spastic cerebral palsy (CP) and painful flat feet. This procedure involves the insertion of a
      trapezoidal bone graft into the calcaneus bone. Both autograft and allografting materials
      have been used for this procedure, but both types of grafting materials have associated
      limitations. Autologous grafting materials, which are harvested from the iliac crest at the
      time of surgery, are associated with high rates of prolonged donor site pain. There is
      limited bone available from the iliac crest. For this reason autologous bone grafts are not
      commonly used for the Evan's procedure. Cadaver allografting materials are variable in their
      mechanical and geometric properties. Recently, xenografting materials have been developed
      that have consistent mechanical properties and are available in a larger size that is formed
      to fit the individual patient intraoperatively. The purpose of this study is to evaluate the
      long term outcomes of the procedure with the different graft options. Another purpose is to
      compare the difference in surgical correction obtained with the cadaver allograft and the
      xenografting materials. This study will also observe and evaluate a wide range of outcome
      variables that encompass multiple levels of patient care, from clinical observation to parent
      and patient satisfaction, and compare these with the observed changes in the radiographic and
      plantar pressure parameters of the foot. This data will be evaluated pre to post surgery and
      for two years of follow-up time. The aim is to uncover the characteristics of collapse
      observed with the two different grafting materials.
    

Detailed description: 
      Primary Outcome Measures:

        1. Measurement on radiographs of distance between heme clips located in calcaneous bone of
           the foot. Within the patient's own calcaneous bone, a heme clip will be placed on each
           side of the osteotomy. From radiographs, the amount of collapse will be determined by
           measuring the distance from one heme clip to the other. Changes in the distance between
           the clips indicate collapse of the graft.

        2. Radiographic measurements of weight bearing feet of the bovine xenograft group and iliac
           crest allograft group (tricortical and bicortical), pre-operatively and
           post-operatively.

             1. Lateral Radiographs: Talocalcaneal angle, Talo first metatarsal angle, Talo
                horizontal angle, and Calcaneal pitch

             2. Anterior-Posterior Radiographs: Talocalcaneal angle, Talo first metatarsal angle,
                and Talonavicular coverage

        3. Comparison of ligamentous laxity between the two grafting material groups, as measured
           by the Beighton measurements at patient's pre-operative orthopaedic clinical
           appointment.

      Secondary Outcome Measures:

      1. Plantar pressures values of interest are of six segments: medial heel, lateral heel,
      medial midfoot, lateral midfoot, first metatarsal and second metatarsal. The center of
      pressure index, total contact area, mean pressure, peak pressure, and pressure time intervals
      will also be collected and assessed to determine pressure distribution of the foot.

      Tertiary Outcome Measures:

      1. Health related quality of life assessments between the two groups, pre-operative and
      post-operative as measured by the Pediatric Orthopaedic Data Collection Instrument (PODCI)
      questionnaire.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children receiving an Evans calcaneal lengthening procedure at Children's Hospital
        Colorado.
      
Keywords: Cerebral palsy; Pes planus; Calcaneal lengthening