Biologic Augmentation of Tibiotalocalcaneal Arthrodesis with Autologous Bone Block is Associated with High Rates of Fusion
Authors: Sherman Alain E. , Mehta Mitesh P. , Nayak Rusheel , Kadakia Anish R. 
Published: November 2020

Category:

Ankle; Hindfoot

Introduction/Purpose:

Tibiotalocalcaneal (TTC) arthrodesis is an established salvage procedure for severe deformities of the hindfoot. Despite its prevalence, end-stage pathology, systemic comorbidities, and the physical demands of surgery often precipitate unsuccessful outcomes, with nonunion rates as high as 85% in medically complex patients. Given the considerable morbidity associated with TTC arthrodesis, there has been recent interest in maximizing the physiologic potential of fusion by means of surgical technique, osteoinductive and osteoconductive biological agents, and vascularized bone flaps. Here, we present a novel approach to TTC arthrodesis using femoral head allograft bone block, bone marrow aspirate, and demineralized bone matrix (DBM) in the absence of tourniquet. Additionally, we explore the role of the medial femoral condyle (MFC) free flap as a reconstructive adjunct to arthrodesis.

Methods:

The sample consisted of 14 patients presenting to a tertiary care facility for reconstructive limb salvage. TTC arthrodesis was performed without tourniquet and biologically augmented with fresh-frozen femoral head allograft, pelvic bone marrow aspirate, and DBM. Three patients with severe soft tissue defects also underwent vascularized osseous reconstruction with MFC free flap. Recovery protocol included three months of prolonged non-weightbearing mechanical stabilization followed by conversion to weightbearing AFO boot for one year. Post-operative plain radiographs and computed tomography (CT) scans were assessed for fusion at regular follow-up. After fusion, participants completed a survey on patient-reported outcomes, which included the modified Foot Function Index (FFI) and Patient-Reported Outcomes Measurement Information System (PROMIS) scales for pain and physical function.

Results:

Successful TTC fusion was documented on plain radiograph in 13 patients (92.9%) and confirmed via CT in 10 patients (90.9%). The mean time-to-fusion was 183.2 +- 83.2 days. One patient (7.1%) failed to achieve fusion and underwent amputation secondary to infectious wound complications. Patients who underwent vascularized bone grafting had more robust healing and significantly shorter time-to-fusion (112.3 +- 31.7 days vs. 204.4 +- 82.7 days, p = 0.05). The mean patient-reported FFI score was found to be 40.96% +- 23.08%, indicating mild-to-moderate impairment in foot function. Similarly, PROMIS data revealed that patients who underwent TTC arthrodesis had a pain T-score of 58.34 (z = 0.83) and a physical function T-score of 39.00 (z = - 1.10), corresponding to mild pain and moderate impairment, respectively.

Conclusion:

We sought to biologically optimize the osteoinductive and osteoconductive potential of TTC arthrodesis using femoral head allograft bone block, bone marrow aspirate, and DBM in the absence of tourniquet. This approach resulted in excellent rates of fusion with minimal pain and preserved function of the lower extremity. Osseous healing was significantly enhanced by MFC flap in patients with soft tissue defects. We, therefore, recommend biologic augmentation of TTC arthrodesis as a viable salvage option for patients facing amputation or other undesirable outcomes.