Biomechanical studies: Science (f)or common sense?
Introduction
It is our impression that many biomechanical studies [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22] invest substantial resources studying the obvious: that more and larger metal is stronger. Studies that evaluate “which construct is the strongest” distract from the more important question: “How strong is strong enough in physiological loading conditions?”.
The purpose of this study is to evaluate if some biomechanical studies comparing fixation constructs just document common sense. If so, there is a need for more careful use of resources in the lab and better collaboration with surgeons to enhance clinical relevance. This study tested our hypothesis that a subset of biomechanical studies comparing fracture fixation constructs can be predicted based on common sense and do not require formal testing. Specifically our primary hypothesis was that outcomes of some biomechanical studies comparing fracture fixation constructs are predictable with high accuracy. Our secondary hypotheses addressed inter-observer reliability and accuracy according to experience and other factors.
Section snippets
Methods
Between 2000 and 2012, we found 105 peer-reviewed biomechanical studies in peer-reviewed orthopaedic journals comparing two or more constructs in order to determine: “Which construct is the strongest?”. We excluded six studies of spine, skull, and facial fractures. From the remaining 99 studies, 12 had a good illustration of the constructs. Among those 12 studies, we selected 11 for which we thought the answer was obvious prior to performing the study [2], [7], [8], [9], [11], [12], [14], [15],
Results
Accuracy was 80% or greater for 10 of 11 studies that have been predicted by members of the SOVG (Table 1). The diagnostic performance characteristics for guessing the results of the study were as follows: sensitivity averaged 84%, ranging from 60% (for study 1) to 99% (for study 7); specificity 86%, ranging from 60% (for study 1) to 99% (for study 7), and accuracy averaged 86%, ranging from 60% (for study 1) to 99% (for study 7). Study 5 was predicted with the highest accuracy (accuracy 97%
Discussion
This study confirms our hypothesis that outcomes of a subset of biomechanical studies – comparing fixation constructs – are quite predictable as accuracy was at least 80% for all but one study. In addition, the secondary null hypothesis that the experience of observers has no influence on the accuracy of predicting outcomes was not rejected because medical students and experienced surgeons performed equally well. In other words, it seems that some comparative biomechanical studies just confirm
Conclusion
According to our findings, a subset of biomechanical studies comparing fracture fixation constructs can be predicted prior to doing the study. As these studies are time and resource intensive, one criterion for proceeding with a biomechanical study should be that the answer is not simply a matter of common sense.
Authors’ contributions
All authors have participated in a material way to at least three of the five elements below: Study design: JJM, JND, TGG, DR. Gathered data: JJM, TGG. Analyzed data: JJM, JND, DR. Initial draft: JJM, JND, DR. Ensured accuracy of data: JJM, JND, TGG, DR. Estimated effort: JJM 50%, JND 20%, TGG 10%, DR 20%.
Conflicts of interest
The authors declare that there are no conflicts of interest.
References (33)
- et al.
Biomechanical comparison of internal fixation techniques for the Akin osteotomy of the proximal phalanx
J Foot Ankle Surg
(2012) - et al.
Screw fixation of scaphoid fractures: a biomechanical assessment of screw length and screw augmentation
J Hand Surg Am
(2006) - et al.
Percutaneous pins versus volar plates for unstable distal radius fractures: a biomechanic study using a cadaver model
J Hand Surg Am
(2007) - et al.
Comparison of three different plating techniques for the dorsum of the distal radius: a biomechanical study
J Hand Surg Am
(2000) - et al.
Reference points for radial head prosthesis size
J Hand Surg Am
(2006) - et al.
A biomechanical study comparing plate fixation using unicortical and bicortical screws in transverse metacarpal fracture models subjected to cyclic loading
J Hand Surg
(2012) - et al.
The biomechanical performance of locking plate fixation with intramedullary fibular strut graft augmentation in the treatment of unstable fractures of the proximal humerus
J Bone Joint Surg Br
(2011) - et al.
Intramedullary rod fixation compared with blade-plate-and-screw fixation for tibiotalocalcaneal arthrodesis: a biomechanical investigation
J Bone Joint Surg Am
(2003) - et al.
Biomechanical comparison of polyaxial and uniaxial locking plate fixation in a proximal tibial gap model
J Orthop Trauma
(2009) - et al.
Fixation of periprosthetic femoral shaft fractures: a biomechanical comparison of two techniques
J Orthop Trauma
(2001)
Medial malleolar fractures: a biomechanical study of fixation techniques
Orthopedics
Cyclic loading of olecranon fracture fixation constructs
J Bone Joint Surg Am
A biomechanical comparison of a biodegradable volar locked plate with two titanium volar locked plates in a distal radius fracture model
J Trauma
Biomechanical evaluation of proximal humeral fracture fixation supplemented with calcium phosphate cement
J Bone Joint Surg Am
Central placement of the screw in simulated fractures of the scaphoid waist: a biomechanical study
J Bone Joint Surg Am
New intramedullary locking nail for olecranon fracture fixation – an in vitro biomechanical comparison with tension band wiring
J Trauma
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2019, Clinical BiomechanicsCitation Excerpt :Load to failure testing of different fixation techniques (Chen et al., 2016; Demirhan et al., 2011; Drosdowech et al., 2011; Little et al., 2012; Renfree et al., 2010; Toogood et al., 2014; Uzer et al., 2017) are reported to range from 100 to 409 N. (Demirhan et al., 2011; Little et al., 2012; Renfree et al., 2010; Uzer et al., 2017). Biomechanical studies typically conclude that “more and larger metal is stronger” though more metal may not necessarily be the best clinical option (Hulsmans et al., 2018; Mellema et al., 2014). Optimal design of clavicle fixation devices requires knowledge of the forces that act on the clavicle during shoulder movements and activities of daily living.
Surgical fixation of midshaft clavicle fractures: A systematic review of biomechanical studies
2018, InjuryCitation Excerpt :For this reason the clinical value of biomechanical studies has raised doubts. Mellema et al. stated that the clinical relevance of biomechanical studies comparing fracture fixation constructs is low since most studies typically conclude by stating that “more and larger metal is stronger” [43]. However, more metal may not necessarily be the best clinical option given that larger implants are more bulky and prominent for instance.
Osteochondritis dissecans of the humeral capitellum: Reliability of four classification systems using radiographs and computed tomography
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Biomechanically superior treatments do not translate into improved outcomes in randomized controlled trials
2022, European Journal of Orthopaedic Surgery and Traumatology
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The members of Science of Variation Group are listed in Appendix.