Motion Predicts Clinical Callus Formation: Construct-Specific Finite Element Analysis of Supracondylar Femoral Fractures

Jacob Elkins; J Lawrence Marsh; Trevor Lujan; Richard Peindl; James Kellam; Donald D Anderson; William Lack

doi:10.2106/JBJS.O.00684

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Motion Predicts Clinical Callus Formation: Construct-Specific Finite Element Analysis of Supracondylar Femoral Fractures

Journal article

Open access

Peer reviewed

Motion Predicts Clinical Callus Formation: Construct-Specific Finite Element Analysis of Supracondylar Femoral Fractures

Jacob Elkins, J Lawrence Marsh, Trevor Lujan, Richard Peindl, James Kellam, Donald D Anderson and William Lack

Journal of bone and joint surgery. American volume, Vol.98(4), pp.276-284

02/17/2016

DOI: 10.2106/JBJS.O.00684

PMCID: PMC5141368

PMID: 26888675

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Abstract

Mechanotransduction is theorized to influence fracture-healing, but optimal fracture-site motion is poorly defined. We hypothesized that three-dimensional (3-D) fracture-site motion as estimated by finite element (FE) analysis would influence callus formation for a clinical series of supracondylar femoral fractures treated with locking-plate fixation. Construct-specific FE modeling simulated 3-D fracture-site motion for sixty-six supracondylar femoral fractures (OTA/AO classification of 33A or 33C) treated at a single institution. Construct stiffness and directional motion through the fracture were investigated to assess the validity of construct stiffness as a surrogate measure of 3-D motion at the fracture site. Callus formation was assessed radiographically for all patients at six, twelve, and twenty-four weeks postoperatively. Univariate and multivariate linear regression analyses examined the effects of longitudinal motion, shear (transverse motion), open fracture, smoking, and diabetes on callus formation. Construct types were compared to determine whether their 3-D motion profile was associated with callus formation. Shear disproportionately increased relative to longitudinal motion with increasing bridge span, which was not predicted by our assessment of construct stiffness alone. Callus formation was not associated with open fracture, smoking, or diabetes at six, twelve, or twenty-four weeks. However, callus formation was associated with 3-D fracture-site motion at twelve and twenty-four weeks. Longitudinal motion promoted callus formation at twelve and twenty-four weeks (p = 0.017 for both). Shear inhibited callus formation at twelve and twenty-four weeks (p = 0.017 and p = 0.022, respectively). Titanium constructs with a short bridge span demonstrated greater longitudinal motion with less shear than did the other constructs, and this was associated with greater callus formation (p < 0.001). In this study of supracondylar femoral fractures treated with locking-plate fixation, longitudinal motion promoted callus formation, while shear inhibited callus formation. Construct stiffness was found to be a poor surrogate of fracture-site motion. Future implant design and operative fixation strategies should seek to optimize 3-D fracture-site motion rather than rely on surrogate measures such as axial stiffness.

Multivariate Analysis

Humans

Middle Aged

Fracture Fixation, Internal - methods

Linear Models

Male

Treatment Outcome

Bony Callus - physiology

Bone Plates

Femoral Fractures - diagnostic imaging

Radiography

Mechanotransduction, Cellular

Biomechanical Phenomena

Movement - physiology

Models, Biological

Fracture Fixation, Internal - instrumentation

Femoral Fractures - surgery

Fracture Healing - physiology

Female

Finite Element Analysis

Aged

Femoral Fractures - physiopathology

Details

Title: Subtitle: Motion Predicts Clinical Callus Formation: Construct-Specific Finite Element Analysis of Supracondylar Femoral Fractures
Creators: Jacob Elkins - Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa
J Lawrence Marsh - Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa
Trevor Lujan - Department of Mechanical and Biomedical Engineering, Boise State University, Boise, Idaho
Richard Peindl - Department of Orthopaedic Surgery, Carolinas Medical Center, Charlotte, North Carolina
James Kellam - Department of Orthopaedic Surgery, University of Texas Health Science Center, Houston, Texas
Donald D Anderson - Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa
William Lack - Department of Orthopaedic Surgery and Rehabilitation, Loyola University Medical Center, Maywood, Illinois
Resource Type: Journal article
Publication Details: Journal of bone and joint surgery. American volume, Vol.98(4), pp.276-284
DOI: 10.2106/JBJS.O.00684
PMID: 26888675
PMCID: PMC5141368
NLM abbreviation: J Bone Joint Surg Am
ISSN: 0021-9355
eISSN: 1535-1386
Publisher: Journal of Bone and Joint Surgery Incorporated; United States
Grant note: P20 GM109095 / NIGMS NIH HHS
Language: English
Date published: 02/17/2016
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Orthopedics and Rehabilitation; Industrial and Systems Engineering
Record Identifier: 9984040258802771

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