What is Arthrofibrosis

Arthrofibrosis is a fibrotic joint disorder. It’s caused by an out-of-control healing response to injury or surgery that creates excessive scar tissue (collagen) and adhesions, and is “fed” by an inflammatory response.

The joint feels stiff, typically has restricted range of motion and is painful in the active phase. Sometimes the cause can’t be identified and this is often the case for shoulder arthrofibrosis, where micro-tears may be responsible. Shoulders are the most common joint affected1.

Arthrofibrosis can affect any joint and is referred to by a number of names including frozen shoulder, adhesive capsulitis, joint contracture, frozen hip, frozen ankle and stiff elbow.

The dysregulated healing response and chronic inflammation that cause arthrofibrosis are complex biochemical processes, and biochemical solutions (medications, supplements and other treatments) are an essential part of treatment1,2.

(Left: a healthy knee. From Usher et. al. 2019)

Inflammation is a key player in arthrofibrosis1. Only after inflammation is properly controlled can the body end the fibrosis process. Therefore, reducing inflammation should be a top priority.

Aggressive physical therapy programs are not appropriate for treating arthrofibrosis, because exercise and aggressive stretching cause inflammation and damage2. Evidence suggests that this is a dangerous approach and a joint should be exercised in the pain-free zone. See more under “Exercise”.

(Left: a knee with generalised arthrofibrosis. Major areas that are affected by arthrofibrosis are indicated. From Usher et. al. 2019)

Evidence from organ fibrosis suggests that there are two forms, an active form in which inflammation and pain are present, and a residual form in which inflammation and pain have resolved, but stiffness remains1. In shoulder arthrofibrosis the residual phase is known as the “frozen phase”. The stiffness of residual arthrofibrosis may resolve over time as the body breaks the collagen bonds in the scar tissue.

However, if inflammation persists arthrofibrosis can’t resolve. The common myth that arthrofibrosis of shoulders and other joints always resolves is not scientifically valid, and the condition can become permanent1. The same is true for all forms of fibrosis, wherever they occur. Early and appropriate treatment is essential.

Estimates of the rates of knee arthrofibrosis following anterior cruciate ligament reconstruction range from 2% to 35%, and after total-knee reconstruction between 2% and 10% with others reporting rates up to 15%.

References

  1. de la Serna, D., Navarro-Ledesma, S., Alayón, F., López, E. & Pruimboom, L. A Comprehensive View of Frozen Shoulder: A Mystery Syndrome. Frontiers in Medicine8, doi:10.3389/fmed.2021.663703 (2021).
  2. Usher, K. M., S. Zhu, G. Mavropalias, J.A. Carrino, J. Zhao, and J. Xu (2019) Pathological mechanisms and therapeutic outlooks for arthrofibrosis. Bone Research 7:9