What is ligament healing like?

I covered a lot of information about ligaments in the first 3 podcasts and then on the 13^th podcast we talked a little more about ligaments.  Ligaments are such a common injury that I would like to spend a little more time talking about ligaments and the repair process.  I hesitate to say the healing process since this gives the idea that there is a good recovery with healing.  That is not the case with ligaments and repair is maybe a more appropriate term. 

Today’s study was published in the Journal of Orthopaedic research in 2002 titled The Healing of sub-failure ligament injury: comparison between immature and mature ligaments in a rat model by Paolo Provenzano et al.  This study set out to evaluate the healing or repair properties of ligament damage.   More specific the repair process of Grade II sprains.  A grade 1 sprain is mild stretch with no discontinuity of the ligaments.  A grade II is a moderate stretch in which some fibers are torn, but enough fibers remain intact so that the damaged ligament has not failed.  A grade III sprain is complete or nearly complete ligament disruption. 

This study reported quote “Ligaments healed with scar tissue that is mechanically inferior and biochemically abnormal in its composition and architecture, concluding that these properties don not return to normal end quote.  

This study followed a group of patients with a grade II MCL sprain (remember a grade 2 sprain is not a complete tear) and even after years none of the patients were able to establish normal knee stability.  This is consistent with prior podcasts showing that ligament damage will disrupt the ligament reflexive control of muscles surrounding a joint leading to the inability to establish joint stability. 

This study showed that the repair process is quote “poorly controlled and consequently does not consistently re-create the cellular and matrix damage done by a grade I or II sprain” end quote.  This study showed that the ageing process impairs ligament healing or repair.  Before skeletal maturity we make embryonic type 1 collagen  and after skeletal maturity we make mature collagen.  They reported that the embryonic type 1 collagen is very important since it is essential to the re-modeling of the cellular matrix in growing animals.  This means that it is adaptable to change.  This study reported that damaged ligaments will heal faster and more completely in the younger and not mature.  Although this study did show that even youth will not have a full recovery of ligament damage and joint laxity and showed that there is continued instability in joints injured at a young age. 

This study showed that most ligament failure was in the ligament and not the ligament to bone insertion.  This shows that we will often have ligament failure without fractures.  I have a lot of insurance adjusters that refuse to believe that a ligament is torn without it causing fractures.  This study showed that most ligament failures do not involve the bone and fractures.

Today’s study did use rats to study the ligaments and it needs to be said that this makes this study a valuable method to understand ligament damage in animals.  The use of rats makes this study possible and is still relatable to humans.  In an ideal world we would be able to have all research done with humans without any harm or being too invasive. 

Real world example

I had an opportunity to do an IME on an 8 year old patient.  She was in a significant MVC and had significant ongoing neck pain years after the MVC.  Motion x-rays showed that she did have AOMSI.  If you are unfamiliar with AOMSI check out the first couple podcasts. 

This was a hard diagnosis to explain to an 8-year-old and her mother.  She did have a very serious injury, but as seen in today’s study she is still producing embryonic collagen that is able to adapt with the changes involved with growth.  Her likely outcome is much better than an older patient who is no longer making the embryonic collagen.  Her ligaments should form with less scare tissue and likely make a reasonable recovery. 

Todays study did show that even in young animals a full recovery of ligament damage and joint laxity is unlikely.  My hope is that her spine will make a great recovery over time given the embryonic collagen that she continues to make.