Fig. 1 Compression testing of a rat spinal fusion segment
Courtesy of Hannah Levy, MD


Published 4/26/2024
Hannah Levy, MD; Janice Bonsu, MD, MPH

Applied Biomechanics Research Offers Numerous Benefits for Orthopaedic Surgery Residents

Editor’s note: This interview is a companion piece to the article “Scott Boden, MD, Offers Insights on Applied Biomechanical Research for Orthopaedic Surgery Residents.”

Engaging in biomechanics research during residency has value far beyond improving performance on in-training exams or fulfilling research requirements. The physical visualization of a joint in motion, loading parameters in cadaveric testing, or finite element computer simulations can enhance a trainee’s understanding of physiologic motion arcs and the soft-tissue versus bone restraints to end range of motion. This article aims to provide a resident’s perspective on the pursuit of biomechanical research during orthopaedic training and provide a framework to guide involvement.

These biomechanical principles translate to clinical evaluation and help link a patient’s presentation and physical exam to their imaging, resulting in a better-informed treatment plan. Grounding education in biomechanics allows for an in-depth education. Take the example of a patient with femoroacetabular impingement. This condition, caused by increased bony constraint, results in mechanical impingement elicited with flexion, adduction, and internal rotation. Knowledge of normal joint mechanics can facilitate quicker recognition of pathologic conditions that increase joint constraint or conversely cause hypermobility or instability.

As residents begin operating, biomechanics can be applicable in cadaveric laboratories. Cadaveric specimens offer residents an opportunity to increase their anatomic knowledge and surgical skills through careful specimen dissection. While working in the lab, residents learn critical operative lessons, such as the degree of iatrogenic destabilization of ligaments before it becomes insufficient or the degree of medial facet resection necessary for thorough lateral recess decompression without causing progression of listhesis.

Ideally, research ideas will naturally spark with a micro-introduction to biomechanical principles in clinics, educational labs, and the OR. When working fracture cases, one might consider mechanical tests of fixation techniques and the fatigue behavior of devices. Although biomechanics research opportunities are readily available in all settings, residents may be deterred from involvement due to a lack of familiarity with equipment or a belief that the time required is not feasible with a busy clinical schedule. There is diversity of institution-specific equipment, access to cadaveric specimens, and funding resources, but there is universal guidance that can demystify resident engagement in biomechanics research.

The following generalized advice may alleviate the early challenges associated with beginning research:

  1. Identify a pathology and question with ongoing debate regarding treatment techniques that would lend well to further mechanical characterization.
  2. Perform a thorough review of relevant literature and develop a careful specimen screening and testing protocol prior to meeting with attendings and technician collaborations. This preparation will enable more useful and timely feedback.
  3. Become familiar with the mechanical testing protocols specific to one’s chosen subspecialty that are under investigation and be sure to reference similar works.
    • For cadaveric testing, this could include identification of a specimen and matching criterion, specimen preparation and potting, injury creation or surgical simulation, testing rigs, preloading and loading conditions, motion and force capture technique and equipment, and ordering of non-destructive followed by destructive testing conditions (Fig. 1). Leverage connections with orthopaedic device representatives to obtain a small supply of instrumentation if necessary for the study design.
    • For finite element analysis, this could include model development or modification based on a representative patient CT scan including meshing into tetrahedral and hexahedral elements and simulating tissues with standard elastic moduli and Poisson ratios, separate modeling of representative instrumentation, internal validation of the model in cadaveric testing, utilization of standard loading conditions (similar to cadaveric study without a toe-in phase), and analysis of range of motion and bone stress in von Mises units.
  4. Use this research as an opportunity to collaborate with mechanical engineering and bioengineering graduate students and career scientists affiliated with one’s institution. This is a great chance for bidirectional learning: The resident can teach orthopaedic principles and surgical techniques to a non-surgeon and, in return, learn more about mechanical simulation and analysis.

Applied biomechanical research can enhance a resident’s clinical and surgical knowledge and decision making, which, in turn, can improve patient care, provide an opportunity for multidisciplinary collaboration, diversify their research portfolio for fellowship applications, and increase their research armamentarium for future project development.

Hannah Levy, MD, is a second-year orthopaedic surgery resident at Mayo Clinic in Rochester, Minnesota.

Janice Bonsu, MD, MPH, is a third-year orthopaedic surgery resident at Emory University in Atlanta and a member of the AAOS Now Editorial Board.