Scientific Retreats 2012

April 23, 2012

Session Topic: Advancing Basic Research on Tendons and Ligaments


Tendons and ligaments are complex biological and structural tissues highly prone to injury, particularly at the sites of attachment to bone and muscle. The sequelae of these injuries can be serious, and have been previously noted to be a major cause of disability in a significant number of the over 107 million adults who sustain a musculoskeletal injury each year (National Health Interview Survey, 2005). To complicate matters further, natural healing processes are slow and inefficient, and often fail to fully restore function. Sports, occupational, and age-related injuries are common to the rotator cuff, Achilles tendon, and anterior cruciate ligament. These types of injuries result in disability and considerable loss in productivity. Further, due to an aging population that is increasingly active, the incidence of these injuries is rising.

Surgical repair is common, but is not always successful. Repairs or replacements can stretch, re-rupture, or develop other complications. Sites of apparently successful flexor tendon repair can develop adhesions that may require extensive physical therapy or additional surgery to restore tendon motion. Surgical repair of large rotator cuff tears show failure rates as high as 90 percent. Even for procedures that are reliably successful, such as autograft transplants for anterior cruciate ligaments, patients can experience changes in joint alignment or mechanical strength, which ultimately restrict movement.

Like surgical repair, new tissue engineering approaches appear to have limited success. NIH support of tendon and ligament research focuses primarily on clinical repair and rehabilitation strategies and pre-clinical tissue engineering experiments; fewer grants focus on basic cellular and molecular aspects of tendon and ligament formation, signal transduction, and mechanisms of pathogenesis.

Basic tendon and ligament research appears to have lagged behind that of other musculoskeletal tissues such as cartilage and bone. Given the public health need, it is reasonable to review what is known about the fundamental development and biology of the tissues, and how current or additional knowledge could inform surgical or engineering approaches to repair or replace damaged tissue.

Goals of the Session

Participants will discuss the current state of knowledge on the biology of tendons and ligaments, ways to enhance the field, and the translation of basic discoveries into improved treatments.

Key Questions

  1. What is the state-of-the-science for basic biology of tendons and ligaments?
  2. Are failures and limitations of the current "bedside" approaches to tendon and ligament injuries pointing to gaps in our understanding of the basic biology of these structures? What are the most immediate clinical needs, and how can these gaps be addressed by investment in basic science?
  3. How have achievements in understanding the basic biology of tendons and ligaments and their components advanced translational and clinical research?
  4. How can knowledge of tendon and ligament developmental biology inform tissue engineering and regenerative medicine approaches?
  5. What are the obstacles, besides funding, in exploring the basic biology of tendons and ligaments? What are the opportunities? Are adequate in vitro and animal model systems available to address research needs?
  6. What are the obstacles, besides funding, to ensure a sustained workforce/pipeline in basic research relevant to tendons and ligaments?


Thomopoulos S, Genin GM, Galatz LM. The development and morphogenesis of the tendon to bone insertion. What development can teach us about healing. J Musculoskelet Neuronal Interact. 2010 Mar;10(1):35-45.

Dourte LM, Kuntz AF, Soslowsky LJ. Twenty-five years of tendon and ligament research. J Orthop Res. 2008 Oct;26(10):1297-305. Review.

Schweitzer R, Zelzer E, Volk T. Connecting muscles to tendons: tendons and musculoskeletal development in flies and vertebrates. Development. 2010 137(17): 2087-2817. Review.