The concept of comparative medicine is almost as old as medicine itself. The ancient Greeks understood that information about the process of life could be gained by dissecting and studying animals.¹ From the comparative anatomical and physiological studies of Galen and William Harvey to the discovery of insulin by Frederick Banting and Charles Best, the careful and detailed studies performed on animals were often responsible for significant advances in human medicine.² The musculoskeletal system is especially well suited to comparative studies, as humans suffer from a variety of acute and chronic disorders of bone and joints that have similar counterparts in animals.¹ Therefore, information gained from one species can often be directly translated to another, thus accelerating advancements in the diagnosis and treatment of musculoskeletal disorders in both man and animals. Because of this, comparative orthopaedic research has served as one of the cornerstones of the "one health" concept for decades.

As early as the 1930s, the concept of comparative orthopaedics was beginning to evolve. Otto Stader, a small animal veterinarian, took a comparative approach to fracture fixation in dogs. After studying the work of Swiss surgeon Gadvilli, Stader developed the first form of external skeletal fixation, the Stader splint, for fracture stabilization in dogs. His work was subsequently translated back to human application by Navy surgeons looking for improved methods of fracture treatment for sailors in World War II. In the 40s and 50s, various methods for intramedullary pinning were being investigated in parallel by physicians and veterinarians. Jacques Jenny, a veterinarian surgeon in this era, performed one of the first intramedullary pinning procedures in animals and significantly advanced the field of comparative orthopaedics by helping to develop successful strategies for fracture repair in horses and humans. In the 50s and 60s, veterinarians were also involved in the development of Sir John Charnley's total hip replacement system for humans using a canine model and participated in the development of internal fixation techniques and instrumentation through collaborations in the AO/ASIF organization. In 1966, Sten-Erik Olsson, VMD, MD and John L. Marshall, DVM, MD, both of whom had degrees in both veterinary medicine as well as human medicine, founded the first laboratory dedicated to comparative orthopaedic research at the Hospital for Special Surgery in New York City. These innovative pioneers have helped to develop, define, and advance the role of comparative orthopaedic research in the "one-health" concept. In addition, they have inspired new generations of comparative orthopaedic researchers around the world.

Today, "one health," comparative orthopaedic laboratories are located throughout the world and typically employ both a comparative and translational research approach in an effort to improve diagnostics, develop preventative and therapeutic strategies, and advance our understanding of disease mechanisms. While comparative research focuses on common pathological and regenerative pathways across species, translational research refers to studies that attempt to extend basic science discoveries into practical clinical applications. An example of a translational research study would be to determine if a drug's ability to increase cartilage cell metabolism could be translated into a clinical treatment of arthritis. Such translational studies are usually carried out in the animal species deemed most appropriate by comparative research investigations and are the "preclinical" foundations on which clinical applications in humans are based. Indeed, many of the current, standard-of-care, orthopaedic procedures associated with meniscal repair and replacement, articular cartilage repair and regeneration, ligament and tendon repair and replacement, and fracture repair have been the products of comparative and translational orthopaedic research studies.

Importantly, the comparative and translational avenues of "one-health" research must always be considered as "two-way bridges." While the knowledge gained and the technologies developed through comparative orthopaedic research are often initially focused on human applications, many of these advancements can be (and have been) brought back to the animal species in which they were originally studied in for veterinary clinical application. Because the majority of comparative orthopaedic research laboratories are directed by veterinarians who have had extensive clinical, as well as research, training, such clinical applications are becoming more common. Advances in total joint replacement, fracture fixation, and cartilage repair are but a few examples of how knowledge flows in both directions on the "two-way bridge" of comparative and translational orthopaedic research.

Comparative orthopaedic research is an excellent example of the evolving paradigm of the "one-health" concept. The multidisciplinary collaborations between physicians, veterinarians, physical therapists, engineers, molecular biologists and a host of other scientific disciplines have yielded, and will continue to yield, significant advancements in the quality of orthopaedic healthcare in both animals and humans.

References

1.  Olsson S-E. Comparative orthopaedics. Clin Orthop Related Res. 1969;62:3–5.

2.  Lyons AS, Petrucelli RJ. Medicine: An Illustrated History. Abradale Press, New York, 1978.