Calcaneal Neck Lengthening Osteotomy - Allogen Bone Graft Material Versus a Hydroxyappatite / β- Tricalcium Phosphate Bone Substitute

Planovalgus or flatfoot deformity is observed in children with different neuromuscular disorders and is associated with pain and gait disorders due to non-reducible talonavicular joint subluxation. Surgical treatment is aimed at correcting foot malalignement and achieving sufficient plantar flexion in the ankle joint. With a calcaneal lengthening osteotomy procedure the planovalgus deformity can be corrected but it requires the use of graft material to be inserted as a bone wedge at the osteotomy site. In this way the talonavicular joint is indirectly reduced. Obtaining autograft material from the iliac crest in growing children carries a risk of growth arrest and iliac wing deformity which has led to widespread use of allograft bone when performing the operation.

New materials are being developed as substitutes for bone graft material with biphasic calcium phosphate ceramic (BCP) being the most commonly used. BCP is a mixture of porous hydroxyapatite (HA) and β-tricalcium phosphate (β -TCP). Calcium phosphate ceramics have excellent biocompatibility and are thought to be able to facilitate and guide new bone growth. This has been demonstrated in experimental studies. In retrospective clinical studies on patients having filled large bone defects with hydroxyapatite graft material radiological healing is seen at follow ups after average 7.9 years. It has also previously been demonstrated that BCP can be used as artificial bone graft in osteotomies with a good result and complete healing of the osteotomi.