Current Concepts and Techniques in Foot and Ankle Surgery

An Overview of Bone Grafting Techniques for the Diabetic Charcot Foot and Ankle

Crystal L. Ramanujam, DPM, MSc ^a, Zacharia Facaros, DPM ^b, Thomas Zgonis, DPM ^a^,^*

^a Division of Podiatric Medicine and Surgery, Department of Orthopaedic Surgery, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MSC 7776, San Antonio, TX 78229, USA

^b Weil Foot & Ankle Institute, 1455 East Golf Road, Des Plaines, IL, USA

^* Corresponding author.

E-mail address: zgonis@uthscsa.edu

Abstract

Surgical options for diabetic Charcot neuroarthropathy of the foot and ankle must take into consideration the challenging environment for bone healing that accompanies these complex pathologic conditions. Bone grafting has established an important role in reconstructive surgery to promote bone formation, replacement, and repair. This article provides an overview of available bone grafting methods in conjunction with a review of the literature on these techniques as they pertain to diabetic Charcot foot and ankle reconstruction.

Keywords

• Bone graft • Autogenous bone • Allogenic bone • Diabetes mellitus • Charcot foot • Reconstructive surgery

Introduction

Diabetic Charcot neuroarthropathy (CN) of the foot and ankle often presents a surgical challenge that requires careful consideration not only for the extent and type of deformity but also for the unique characteristics of the bone and soft tissue envelope involved with this patient population. Although the exact pathophysiologic mechanism of diabetic CN is unknown, current research has alluded to variations in bone physiology among patients with and without diabetes, peripheral neuropathy, and CN. These differences have contributed to changes in the way patients with diabetic CN are approached with regard to surgical reconstruction of the foot and ankle. Surgical techniques have evolved to include better fixation methods and designs, in addition to materials that can augment the construct for improved structural and functional outcomes. In this respect, bone grafting has gained an important role in the complex reconstruction of diabetic CN foot and ankle deformities. Bone graft provides for the replacement of variable bone loss and enhancement of bone healing. Several choices exist among autograft, allograft, and bone graft substitutes, which can be tailored according to the overall clinical picture. An overview of several available options and specific applications is presented to maximize the surgeon’s understanding of bone grafting in the diabetic CN foot and ankle.

Autogenous bone grafting for the diabetic Charcot foot and ankle

Autogenous bone graft remains the gold standard because of complete histocompatibility and no chance for disease transmission; however, its shortcomings include donor-site morbidity, limited supply, and increased surgical time.¹ Fred Albee² first described human autologous bone grafting in 1914 in which a patient’s tibial bone was used for their spinal fusion. Today, types of autograft include cortical, cancellous, vascularized, and bone marrow aspirate. Autogenous cancellous graft is typically used as a nonstructural graft, frequently seen in arthrodesis. Cortical autograft provides structural support, therefore, allowing its use to span defects.

The most commonly used autogenous bone graft is the iliac crest (ICBG), which is harvested from either the anterior or posterior aspects and can be taken in the specific shape to span the defect.³ For ankle arthrodesis in patients with CN, the ICBG is typically harvested from the contralateral side.⁴ A study by El-Gafary and colleagues⁵ on 20 patients with chronic CN deformities successfully used external fixation and corticocancellous bone graft harvested from the iliac crest for arthrodesis sites after debridement of necrotic and loose bone at the midfoot, hindfoot, and/or ankle. Shah and colleagues⁶ used ICBG with monolateral external fixation or intramedullary nailing for ankle arthrodesis in 11 patients with chronic CN. Despite the advantages and versatility of ICBG, its complications at the donor site have been well reported, including infection, pain, sensory loss, hematoma formation, blood loss, and extended operating time.³

The disadvantages associated with ICBG have led to increased use of alternate harvest sites. Simon and colleagues ⁷ demonstrated successful tarsometatarsal arthrodesis using autologous cancellous graft harvested from the proximal tibia and internal fixation in 4 patients for the treatment of acute CN, whereas Deresh and Cohen⁸ demonstrated successful midfoot and hindfoot arthrodesis using corticocancellous autograft harvested from the distal tibia for CN reconstruction.

The fibula can also be harvested for use as a cortical strut graft; however, postoperative complications in the literature have included differing degrees of pain and muscle weakness.⁹ Jeong and colleagues¹⁰ demonstrated stable CN ankle fusion using nonvascularized fibular graft with external fixation (Fig. 1). Free vascularized fibula graft provides better mechanical support because of earlier incorporation and has been reported in ankle arthrodesis for salvage following extensive osteomyelitis.¹¹ Small amounts of cancellous bone can be harvested from the calcaneus, with the lateral wall as the most common harvest site; however, other autogenous bone graft sites are considered better sources because of the limited amounts available for harvest and the possibility of interference with common arthrodesis sites in CN foot and ankle reconstruction.¹²