A Review of Bone Growth Stimulation for Fracture Treatment

Steve B. Behrens; Matthew E. Deren; Keith O. Monchik

Disclosures

Curr Orthop Pract. 2013;24(1):84-91. 

In This Article

Introduction

Nonunions

An estimated six million fractures occur every year in the United States, with approximately 5% or 300,000 becoming nonunions.[1] Nonunions develop for a variety of reasons, including a large fracture gap, inadequate immobilization, malaligned fracture ends, infection, and inadequate vascular resources. In general, a nonunion is established when a fracture site shows no visible progressive signs of healing. The Health Care Financing Administration (Medicare) defines a nonunion and indications for bone growth stimulation as (1) nonunion of long bone fracture defined as radiographic evidence that fracture healing has ceased for 3 or more months before starting treatment with the osteogenesis stimulator, and (2) nonunion of long bone fracture documented by a minimum of two sets of radiographs obtained before starting treatment with the osteogenesis stimulator, separated by a minimum of 90 days, each including multiple views of the fracture site, with a written interpretation by a physician stating that there has been no clinically significant evidence of fracture healing between the two sets of radiographs.[2]

Boyd et al.[3] investigated nonunions in 842 patients in 1965 and found a 35% incidence of nonunion in the tibia, 19% incidence in the femur, 7.5% in the humerus, 15.5% in the forearm, and 2% in the clavicle. In 1981, Connolly,[4] in a series of 602 patients, showed a much higher incidence of nonunion in the tibia (62%), femur (23%), humerus (7%), forearms (7%), and clavicle (1%), suggesting an increased frequency of tibial nonunion over time. The cost of a nonunion has been estimated between $23,000–$58,000, including initial surgery with grafting, frequent office visits, patient quality of life, and opportunity cost of missed work.[5] Treatment options consist of invasive surgical techniques, such as internal and external fixation, bone grafting, and in extreme cases, amputation. Noninvasive options include bone growth stimulation.

Methods of Article Retrieval

A PubMed search was performed for basic science and clinical articles regarding bone growth stimulation in the English language. Articles were assessed for study design, size, validity (with previously published literature), technology used, and method of treatment. The search identified articles from 1957 to present. These articles were reviewed, and ten additional references (i.e. book chapters) were analyzed as well. Meta-analysis of the data on bone growth stimulators for delayed and nonunion of fractures is difficult because of the heterogeneity of various trials and device specifications. Large, randomized, placebo-controlled trials are lacking, and much of the data reflect larger case series and comparative studies.

History of Bone Growth Stimulation

Christian Kratzenstein first described electricity for the treatment of rheumatism and the plague by using ''good electricity'' to replace ''bad electricity'' in 1744.6,7 Boyer described the effect of electricity on the healing of a tibial fracture in 1816.[8] By 1850, Mott[9] and Lente[10] documented the successful treatment of ununited fractures by electricity, and Garratt[11] later placed needles into a femoral fracture for healing. Wolff[12] published his chief premise in 1892, asserting that the architecture of living bone continuously adapts to surrounding operational stresses, which results in precise and efficient structural patterning. His work, now known as Wolff's Law, states that the structure of bone adapts to changes in its stress environment.

The study of electricity and medicine continued into the 20th century, with Becker and Selden[13] exploring new pathways in the understanding of evolution, acupuncture, psychic phenomenon, and healing. In 1954, Fukada and Yasuda[14] published a study on the piezoelectric properties of dry bone and stress-generated electrical potentials directly relating to callus formation.[14] In 1962, Becker et al.[15] and Bassett et al.,[16] described the electrical properties of hydrated bone, which was later confirmed by Friedenberg and Brighton[17] in 1966. Shamos and Lavine,[18] in 1967, investigated piezoelectric properties of biological tissues, and in 1968, Anderson and Eriksson[19] published their work on electrical properties of hydrated collagen, providing a working model for Wolff's Law. Different technology has been tested for the biophysical stimulation of bone formation, including extracorporeal shock-waves,[20] electrical and electromagnetic (capacitive coupling, combined magnetic fields, direct current, and pulsed electromagnetic fields),[21] laser,[22] mechanical,[23] and ultrasound.[24,25]

Levels of Evidence and Recommendation Grading

Identifying well-designed and unbiased clinical trials aids in decision-making for today's orthopaedic surgeons. Levels of evidence help to categorize trials and develop recommendations. Level I evidence consists of randomized controlled trials with significant difference, or those without significant difference but with narrow confidence intervals.[26] Also included are systematic reviews or meta-analyses of homogenous Level I trials.[26] Level II evidence consists of prospective cohort studies, randomized controlled trials of poor quality, and systematic review of Level II studies or nonhomogenous Level I trials.[26] Case-control studies, retrospective cohort studies, and systematic review of Level III studies comprises Level III evidence.[26] Level IV evidence is based on case series without control groups, or relies on historical control groups for comparison.[26] And finally, Level V evidence, consists of expert opinion.[26]

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