The use of structural and non structural bone grafts and substitutes in osteotomies and arthrodesis of the hindfoot and ankle

Introduction: Hindfoot fusions and osteotomies implicate the decision whether to use an autologous bone graft or an osteoconductive or –inductive substitute material in order to promote bony union and/or to support the correction of an additional hindfoot deformity. Evidence directing this decision is missing. The goal of this thesis is to retrospectively quantify the use of structural and non structural bone grafts in the foot and ankle clinic of the University of Basel over a one year period and to assess the time to union achieved with each different type of graft in specific hindfoot fusions or osteotomies carried out at level of the ankle, subtalar, chopart und Lisfranc joint.
Methods: We retrospectively identified all patients who underwent fusions or osteotomies of the hindfoot from January 2006 until December 2006 using the in house electronic database „opdz“ recording all surgical procedures carried out at the institution of the University of Basel. Patients were then allocated to four treatment groups including: 1) ankle fusion and osteotomies 2) hindfoot (talonavicular, subtalar and triple) arthrodesis 3) calcaneal osteotomy and 4) midfoot arthrodesis and osteotomies. Within these major treatment categories, patients who received the same or no bone graft were further pooled in subgroups. Average time to union, rates of non - and delayed was calculated for each of the above mentioned subgroups and compared to each other within the respective treatment categories.
Results: We identified 108 patients (50 male, 58 female, mean age 56.5 +/- 15.3 years) undergoing 90 fusions and 36 osteotomies at the level of the ankle, subtalar, Chopart or Lisfranc joint from January to December 2006. Thereby, 3 patients underwent revision of their arthrodesis within the follow up time. Another 15 underwent combined osteotomies or arthrodesis during the same procedure. Acellular allografts (Tutoplast®) and demineralised bone matrix (DBM) were the most often used structural and non structural bone graft respectively. Given the limited number of patients receiving the same graft in a specific procedure, comparison of time to union could only performed for structural and non structural bone grafts in triple/subtalar arthrodesis. In this category, there was no difference between acellular allograft mediated arthrodeses carried out either with or without DBM. Furthermore, there was no difference between in situ arthrodeses carried out without any graft or with the application of DBM.
Conclusion: Many different structural and non structural bone grafts and substitutes are used in fusions and osteotomies in today’s foot and ankle surgery for structural support or acelleration of bony healing. The current literature only provides sparse data on the efficacy of both natural bone grafts and their substitutes. Their true efficacy must further be evaluated in prospective randomized studies.