Foot & Ankle International - September 2019 - 1068

851468
research-article2019

FAIXXX10.1177/1071100719851468Foot & Ankle InternationalDaniels et al

Article

Recombinant Human Platelet-Derived
Growth Factor BB in Combination With
a Beta-Tricalcium Phosphate (rhPDGFBB/β-TCP)-Collagen Matrix as an
Alternative to Autograft

Foot & Ankle International®
2019, Vol. 40(9) 1068--1078
© The Author(s) 2019
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https://doi.org/10.1177/1071100719851468
DOI: 10.1177/1071100719851468
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Timothy R. Daniels, MD, FRCSC1 , John Anderson, MD2,
Michael P. Swords, DO3, Greg Maislin, MS, MA4, Rafe Donahue, PhD5,
Ellie Pinsker, BA&Sc1, and Jovelyn D. Quiton, MSc5

Abstract
Background: Joint arthrodesis often employs autograft to promote union; graft harvesting can lead to perioperative
morbidity. A Canadian randomized controlled trial (RCT) demonstrated that recombinant human platelet-derived growth
factor BB homodimer (rhPDGF-BB) combined with beta-tricalcium phosphate (β-TCP)-collagen was a safe, effective
alternative to autograft. This multicenter North American RCT compared the safety and efficacy of rhPDGF-BB/β-TCPcollagen with autograft for ankle and hindfoot fusion. Subclassification using propensity scores (PS) incorporated patients
from previous trials for enhanced statistical power for noninferiority testing and broader review of treatments.
Methods: Patients requiring ankle or hindfoot arthrodesis and supplemental bone graft were treated with rhPDGFBB/β-TCP-collagen (n = 69) or autograft (n = 35). Outcomes included joint fusion on computed tomography (24 weeks),
clinical healing status, visual analog scale (VAS) pain, Short-Form 12 (SF-12), American Orthopaedic Foot & Ankle Society
(AOFAS) Ankle-Hindfoot Scale, and Foot Function Index (FFI) scores over 52 weeks. PS methodology addressed potential
selection bias arising from pooling data among these patients and 2 previous RCTs with similar inclusion criteria, surgical
techniques, graft harvest techniques, and outcomes. All 132 rhPDGF-BB/β-TCP-collagen-treated patients and 167 of 189
candidate autograft-treated controls were selected for comparison by an independent statistician blinded to outcomes.
Results: In the PS subclassification, 68.1% treatment patients and 68.4% controls achieved >50% osseous bridging at
fusion sites. Clinical healing status was achieved in 84.8% of treated patients and 90.7% of controls at 52 weeks. Clinical,
functional, and quality of life results demonstrated noninferiority of rhPDGF-BB/β-TCP-collagen to autograft. Safetyrelated outcomes were equivalent.
Conclusion: PS subclassification analysis of 3 RCTs demonstrated that rhPDGF-BB/β-TCP-collagen was as effective as
autograft for ankle and hindfoot fusions, with less pain and morbidity than treatment with autograft.
Level of Evidence: Level I, prospective randomized study.
Keywords: ankle fusion, autogeneous bone graft, collagen, hindfoot fusion, nonunion, platelet-derived growth factor,
rhPDGF-BB, randomized controlled trial, propensity score cohort analysis

Introduction
End-stage ankle and hindfoot arthritis culminates in marked
musculoskeletal pain, limited function, and impaired quality of life equivalent to that observed with end-stage hip
arthritis.19 Ankle and hindfoot arthrodesis reduces pain,
improves function, and corrects bony deformity. The most
common complication following ankle arthrodesis is nonunion. A meta-analysis of 39 studies of ankle arthrodesis in
1262 patients reported an overall nonunion rate of 10%,21

Division of Orthopaedic Surgery, St. Michael's Hospital, and University
of Toronto, Toronto, ON, Canada
2
Orthopaedic Associates of Michigan, Grand Rapids, MI, USA
3
Michigan Orthopedic Center, Lansing, MI, USA
4
Biomedical Statistical Consulting, Wynnewood, PA, USA
5
Wright Medical Technology, Inc, Franklin, TN, USA
Corresponding Author:
Timothy R. Daniels, MD, FRCSC, Division of Orthopaedic Surgery, St.
Michael's Hospital, and University of Toronto, St. Michael's Hospital, 800
- 55 Queen Street East, Toronto, ON M5C 1R6, Canada.
Email: danielst@smh.ca

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