Biomechanical methods for the assessment of fracture repair

Augat, Peter; Faschingbauer, M.; Seide, K.; Tobita, Kenji; Callary, Stuart A.; Solomon, Lucian B.; Holstein, Joerg H.

doi:10.1016/j.injury.2014.04.006

Cited by 58 publications

(49 citation statements)

References 32 publications

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“…Additionally, during the relatively slow process of primary bone healing, there are little to no visible changes on plain radiographs . Thus, there is a critical need to discern the mechanical stability of the fracture site prior to callus calcification . As healing progresses it is advantageous to quantify implant load, because not only does the plate load reflect the size of the callus, but also the degree of mineralization within the fracture site .…”

Section: Discussionmentioning

confidence: 99%

Implantable microelectromechanical sensors for diagnostic monitoring and post‐surgical prediction of bone fracture healing

McGilvray

Ünal

Troyer

et al. 2015

Journal Orthopaedic Research

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ABSTRACT:The relationship between modern clinical diagnostic data, such as from radiographs or computed tomography, and the temporal biomechanical integrity of bone fracture healing has not been well-established. A diagnostic tool that could quantitatively describe the biomechanical stability of the fracture site in order to predict the course of healing would represent a paradigm shift in the way fracture healing is evaluated. This paper describes the development and evaluation of a wireless, biocompatible, implantable, microelectromechanical system (bioMEMS) sensor, and its implementation in a large animal (ovine) model, that utilized both normal and delayed healing variants. The in vivo data indicated that the bioMEMS sensor was capable of detecting statistically significant differences (p-value <0.04) between the two fracture healing groups as early as 21 days post-fracture. In addition, post-sacrifice microcomputed tomography, and histology data demonstrated that the two model variants represented significantly different fracture healing outcomes, providing explicit supporting evidence that the sensor has the ability to predict differential healing cascades. These data verify that the bioMEMS sensor can be used as a diagnostic tool for detecting the in vivo course of fracture healing in the acute post-treatment period. ß

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Section: Discussionmentioning

confidence: 99%

Implantable microelectromechanical sensors for diagnostic monitoring and post‐surgical prediction of bone fracture healing

McGilvray

Ünal

Troyer

et al. 2015

Journal Orthopaedic Research

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“…The cantilevered pin provides a degree of mechanical gain based on the ratio of pin length to bone diameter. This mechanical gain is advantageous since angular deflection and interfragmentary motion are normally too small to be effective indicators of bone healing with standard radiography 13 . As the plate bends from load sharing with the healing bone, the pin moves relative to the hole pattern on the internal scale.…”

Section: Introductionmentioning

confidence: 99%

Implantable strain sensor to monitor fracture healing with standard radiography

Pelham

Benza

Millhouse

et al. 2017

Sci Rep

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Current orthopaedic clinical methods do not provide an objective measure of fracture healing or weight bearing for lower extremity fractures. The following report describes a novel approach involving insitu strain sensors to objectively measure fracture healing. The sensor uses a cantilevered indicator pin that responds to plate bending and an internal scale to demonstrate changes in the pin position on plain film radiographs. The long lever arm amplifies pin movement compared to interfragmentary motion, and the scale enables more accurate measurement of position changes. Testing with a human cadaver comminuted metaphyseal tibia fracture specimen demonstrated over 2.25 mm of reproducible sensor displacement on radiographs with as little as 100 N of axial compressive loading. Finite element simulations determined that pin displacement decreases as the fracture callus stiffens and that pin motion is linearly related to the strain in the callus. These results indicate that an implanted strain sensor is an effective tool to help assess bone healing after internal fixation and could provide an objective clinical measure for return to weight bearing.While a variety of fracture stabilization therapies are available to surgeons for internal fixation, the inability to directly evaluate healing remains a limiting factor when assessing patient recovery and return to a pre-injury activity level. Tibial fractures are the most common long-bone fracture (36.7% of all long-bone fractures in adults) and also happen to be the most common site of long-bone nonunion 1 . Patients with nonunion are more likely to have additional fractures during follow-up, to require various types of in-patient and surgical care (including amputation), to be prescribed pain medications (especially strong opioids), and to use more outpatient physical therapy than those with proper bony union 2 . Median total costs of care for patients with nonunion were found to be more than double those without ($25,556 vs. $11,686 according to 2006 data) 2 . To help prevent complications such as non-union or malunion, refracture and implant failure, physicians often limit weight bearing for an extended time, often 12 weeks or longer, to allow for adequate bone growth 3 . While premature weight bearing can increase the rate of complications, unnecessarily delaying weight bearing results in productivity loss with indirect costs from lost wages and places additional burdens on the healthcare system. Identification of post-operative complications (non-union, infection, implant loosening, etc.) throughout the recovery process, while critical to effective treatment, is often difficult with existing internal fixation methods.Current clinical methods of monitoring bone healing and identifying complications following an open-reduction and internal fixation (ORIF) are typically limited to a combination of symptomatic, physical examination, and radiographic findings. Interpretation is subjective, influenced both by the patient's candid description of symptoms and by the treati...

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“…Healing in bones requires 4 to 40 weeks depending on the number of fractures, the age and the type of the bone. According to literature there is no standard defining when a fracture is healed, therefore the evaluation of a healing fracture is based on predetermined time points [15]. The development of an implanted antenna monitoring system could provide orthopedics with a continuous indicator of the bone's condition.…”

Section: Introductionmentioning

confidence: 99%