Ligament Injury and Healing: A Review of Current Clinical Diagnostics and Therapeutics

Abstract

Ligament injuries are among the most common causes of musculoskeletal joint pain and disability encountered in primary practice today. Ligament injures create disruptions in the balance between joint mobility and joint stability, causing abnormal force transmission through the joint, which results in damage to other structures in and around the joint. The long-term consequence of nonhealed ligament injury is osteoarthritis, the most common joint disorder in the world today.Ligaments heal through a distinct sequence of cellular events that take place in three consecutive stages: an acute inflammatory phase, a proliferative or regenerative phase, and a tissue remodeling phase. The process can take months to resolve itself, and despite advances in therapeutics, many ligaments do not regain their normal tensile strength.Various diagnostic procedures have been used to determine and assess ligament injury. Traditionally, MRI and X-rays have been the most utilized techniques; however, because ligaments do not show up clearly with these devices, there have been many false positives and negatives reported due to inconclusive or inaccurate readings. Newer technologies, such as ultrasound and digital motion X-ray, are able to provide a more detailed image of a ligament's structure and function.Numerous strategies have been employed over the years attempting to improve ligament healing after injury or surgery. One of the most important of these is based on the understanding that monitoring early resumption of activity can stimulate repair and restoration of function and that prolonging rest may actually delay recovery and adversely affect the tissue's response to repair. Likewise, there is a shift away from the use of steroid injections and nonsteroidal antiinflammatory medications. Although these compounds have been shown effective in decreasing the inflammation and pain of ligament injuries for up to six to eight weeks, their use has been shown to inhibit the histological, biochemical, and biomechanical properties of ligament healing. For this reason their use is cautioned against in athletes who have ligament injuries. Such products are no longer recommended for chronic soft tissue injuries or for acute ligament injuries, except for the shortest possible time, if at all.Regenerative medicine techniques, such as prolotherapy, have been shown, in both case series and clinical studies, to resolve ligament injuries of the spine and peripheral joints. More research and additional studies are needed to better assess ligament injuries and healing properties.

Structural Basis of Joint Instability as Cause for Chronic Musculoskeletal Pain and Its Successful Treatment with Regenerative Injection Therapy (Prolotherapy)

“…Damage to the ACL causes the highest incidence of pathologic joint instability [26,27]. ACL ruptures, in some cases, are associated with marked short term morbidity and long-term consequences, such as degeneration of the joint surfaces, development of osteoarthritis, moderate to severe disabilities, joint instability and chronic pain [24,28,29]. ACL damage typically occurs in the younger population and, as such, leads to prolonged disability and economic cost largely due to work loss [30].…”

“…As a full recovery to its pre-injury abilities does not occur, the joint is subjected to instability. This inevitably leads to biomechanical changes across joint surfaces, increasing the risk for degenerative changes and the development of osteoarthritis [24,28,32,33]. In few cases, through a three-stage overlapping healing process (hemorrhage with inflammation, cellular and matrix proliferation and finally, remodeling and maturation), the body may be able to repair the injury enough for a full clinical recovery of the initial structural/functional abilities (i.e., strength and ability to stabilize the joint), but this healing process can take months to resolve itself and underlying instability may still be present.…”

“…Studies on athletes who were followed for 5 to 12 years after a ligament injury have revealed an early onset of OA of the joint and an inability to return to their pre-injury level of activity [28,[35][36][37][38]. At 10 years 21%-48% of these athletes were found to have OA.…”

“…A separate study on female athletes for 12 years after an ACL injury reported that 50% of the females had radiographic OA and approximately 80% had other features of OA [39]. Thus, sports trauma, which begins with ligament injury and subsequent laxity, can cause joint instability, which then leads to chronic pain, diminished function, and ultimately to OA of the affected joint [28,35,38]. Despite the use of numerous strategies over the years, attempts to improve ligament healing after injury have not been entirely successful.…”

“…Despite the use of numerous strategies over the years, attempts to improve ligament healing after injury have not been entirely successful. OA remains one of the long-term consequences of ligament injury and continues to be the most common joint disorder of the world [28,40,41]. Therefore, understanding the complex cellular processes that occur after ligament injury, as well as determining and implementing those strategies that optimize ligament restoration, are necessary steps in reducing the enormous individual and public health burden of ligament injury-associated OA and its related chronic musculoskeletal pain.…”