Evolution of functional tissue engineering for tendon and ligament repair

Abstract

This review paper is motivated by a Back‐to‐Basics presentation given by the author at the 2022 Orthopaedic Research Society meeting in Tampa, Florida. I was tasked with providing a brief history of research leading up to the introduction of functional tissue engineering (FTE) for tendon and ligament repair. Beginning in the 1970s, this timeline focused on two common orthopedic soft tissue problems, anterior cruciate ligament ruptures in the knee and supraspinatus tendon injuries in the shoulder. Historic changes in the field over the next 5 decades revealed a transformation from a focus more on mechanics (called “bioMECHANICS”) on a larger (tissue) scale to a more recent focus on biology (called “mechanoBIOLOGY”) on a smaller (cellular and molecular) scale. Early studies by surgeons and engineers revealed the importance of testing conditions for ligaments and tendons (e.g., high strain rates while avoiding subject disuse and immobility) and the need to measure in vivo forces in these tissues. But any true tissue engineering and regeneration in these early decades was limited more to the use of auto‐, allo‐ and xenografts than actual generation of stimulated cell‐scaffold constructs in culture. It was only after the discovery of tissue engineering in 1988 and the recognition of frequent rotator cuff injuries in the early 1990s, that biologists joined surgeons and engineers to discover mechanical and biological testing criteria for FTE. This review emphasizes the need for broader and more inclusive collaborations by surgeons, biologists and engineers in the short term with involvement of those in biomaterials, manufacturing, and regulation of new products in the longer term.

Does mechanical loading restore ligament biomechanics after injury? A systematic review of studies using animal models

“…The most recent study included in the current review was published in 2005. This may reflect temporal trends in human ligament research, with an increased focus on surgical management, orthobiologic therapies, [ 69 ] and functional tissue engineering [ 70 ]. These innovations are important, but a large proportion of ligament injuries will continue to be managed conservatively.…”

Tendon cell and tissue culture: Perspectives and recommendations

“…Lastly, when working to translate a tissue engineering approach to the clinic, it is highly encouraged to collaborate with clinicians and members of industry to gain their unique perspectives and ensure that their concerns are also addressed. This was noted in the 2007 Functional Tissue Engineering Conference, where in addition to proper biomechanical function, surgeons were concerned with aspects relating to construct handling and fixation during implantation (e.g., suture retention) and safety, whereas members of industry saw regulatory and economic factors (e.g., FDA regulation, reimbursement, market size) as important considerations 96 . Therefore, collaborative teams between tissue engineers, surgeons, and members of industry are important to develop engineered constructs that will work, are economically feasible, and that surgeons are willing/able to use.…”

Bionic Functional Surgical Suture with Hierarchical Micro–Nano Dimensions for Rotator Cuff Repair: Inducing Process‐Matching Mechanobiological and Biological Responses Adapted to the Regeneration

“…[6,[12][13][14][15][16][17][18][19][20][21] Given the biomechanical characteristics of the native RC, the effective regeneration process after the repair is highly related to the particular requirements of mechanical stimulus. [22][23][24] The initial strength and mechanical behavior of the conventional surgical suture (SS) are limited, which may fail to provide promising repair performance throughout the healing process. Its long degradation cycle or nondegradability characteristics produce persistent sheltering and occupancy effects in the mid-to-late stage.…”