New Bone Grafting Technique in Paediatric Foot Surgery. Validation of Outcome Measures

• Visual Analog Scale [ Time Frame: 12 hrs ] [ Designated as safety issue: No ]
  The pain will be assessed within the first 24 hrs
  
  

• Radiographic stereometric assay (RSA) [ Time Frame: The RSA will be taken at baseline and the final investigation at 12 months ] [ Designated as safety issue: Yes ]
  RSA wille be taken immediately postoperative, after 6 weeks, after 8 weeks, after 6 months and after 12 months. In this way the investigators will evaluate the healing progress and be able to assess eventual microluxation in the cuboideum relatively to calcaneus.
  
  

• Pedobarography [ Time Frame: preoperative, 6 months, 12 months ] [ Designated as safety issue: No ]
  Preoperative: The ambulatory examination prior to surgery. Pedobarography: The investigators use a pressure plate from Tekscan. The pressure of the patients feet is measures during stance and walking.
  
  

Study C: HA-β TCP (ReproBone™) vs. autologous iliac crest bone graft in a calcaneal lengthening osteotomy in children with hindfoot valgus. A clinical randomized controlled study with 12 months of follow-up.

Purpose. To investigate the clinical and radiographic findings of a calcaneal lengthening osteotomy by comparing autologous bonegraft and HA-β-TCP graft in a group of children with hindfoot valgus deformities. The primary outcome measure is pain score (visual analog scale). We expect children who are randomized to HA-β-TCP graft to have less postoperative pain than children randomized to autologous bone graft.

Design. Prospective, randomized controlled study.

Randomization: Children who fulfill the criteria for inclusion together with their parents/guardian receive information about the project. The patients are randomized to respectively HA-ß-TCP and iliac crest bone graft.

Surgical procedure: Calcaneal lengthening osteotomy is performed between the anterior and middle facet of the subtalar joint. The corticalis of the calcaneus is bilaterally cut through. The planovalgus deformity is corrected and with a graft matching the wedged osteotomy is inserted. Tantalum balls are inserted into calcaneus on each side of the osteotomy and in cuboideum. Postoperative pain treatment consist of a tibial nerve catheter which is used the first 24 hours. Patients in whom graft is harvested from the iliac crest get local infiltration analgesics accordingly to a standardized procedure. The pain is registered by the use of a visual analog scale (VAS) a 3, 8 and 12 hours postoperative. The amounts of used analgesics are registered.

Power and significance: The primary parameter is postoperative pain score. We expect the use of artificial bone graft will reduce the VAS score from 60 mm to 30 mm. A reduction of 30 mm corresponds to a significant fall in pain intensity. With reference to a former published study on a comparable patient group we expect a standard deviation of 25 mm in the population. Therefore the number of patients in each group should be 12 in order to demonstrate a significant difference of 30 mm. We strive towards 2x15 patients in order to compensate for eventual drop-outs. We used an non-paired design with power = 80 % of p < 0.05%.