Ligament and tendon damage from Immobilization syndrome
In this article, we review various aspects of short and long-term immobilization of an injured joint, specifically the damage to the tendons and cartilage. Immobilization syndrome has been implicated in being a developmental cause of long-term chronic joint pain. If you have questions about immobilization syndrome you can get help and information from our Caring Medical staff.
Typically, when someone injures a limb or joint, whether by breaking or fracturing bones or by tearing the soft tissue, the injured person is put into a cast, brace, splint, or other device that will help the injured area “stay still.” When it comes to ligaments or tendons, research has shown that soft tissue is significantly affected by the absence of joint motion.
Immobilization, or stress deprivation, is a term to describe casting, splinting, taping, or other means of limiting movement to an injured area of the body. Immobilization is part of the RICE therapy which involves rest, ice, compression, and elevation. Immobilization syndrome refers to the results of short-term as well as long-term immobilization, the symptoms of which are: very stiff joints, muscle atrophy, joint degeneration, and chronic pain.
Immobilization syndrome is a painful component of conditions such as Complex Regional Pain Syndrome, osteoarthritis, and frozen shoulder, also known as adhesive capsulitis.
Immobilization, or stress deprivation, is a term to describe casting, splinting, taping, or other means of limiting movement to an injured area of the body
Immobilization can be detrimental to ligament healing and should not be done casually, though it is sometimes necessary under medical supervision. In our office, it may be used early in the treatment course for more severe cases of instability. Immobilization is generally discouraged in most cases because it can cause the following changes:
- Proliferation of fatty connective tissue within the joint.
- Cartilage damage and cartilage cell necrosis (death).
- Scar tissue formation and articular cartilage tears.
- Increased randomness of the collagen fibers within the ligaments and connective tissues
- Ligament weakening with a decreased resistance to stretch.
When bone replaces cartilage in immobilized knees: In prolonged immobilization bone replaces cartilage and the effects are irreversible
Because of the detrimental nature of trying to study soft tissue damage following joint immobilization, much of the published research in studies performed in mice or rats. A 2018 study from hospital and university researchers in Canada published in the journal Bone (1) made observations to suggest that weight-bearing exercise and joint motion be instigated as quickly as possible. Here is what they said:
- Lost joint range of motion (ROM) is common in chronic osteoarthritis, alters regional weight-bearing across the articular surfaces, and contributes to loss of cartilage and bone alterations. In prolonged immobilization bone replaces cartilage and the effects are irreversible.
- In this animal study, eleven rat knees were rigidly immobilized for 32 weeks
- Immobilized cartilage had increased collagen I content (scar tissue)
- Articular cartilage was thinner
- The severity of osteoarthritis increased as measured by Mankin scores
- The trabecular bone plate area (the spongy bone at the end of long bones like the thigh and shin bones) at the front and back of the shin showed bone loss, but not in the middle.
- Chondral vascular ingrowth was seen in the subchondral bone. This means that blood supply was increased to the bone as the cartilage and outer bone were dying. The center of the knee joint was being fortified as we see in the fact that bone loss was not seen in the center of the top of the tibia bone.
- In summary: Bony replacement characterizes articular cartilage degeneration of knees immobilized for 32 weeks in the anterior, non-weight-bearing region of the tibia. Replacement of cartilage by bone may have been mediated by chondral vascularization, suggesting irreversible changes. These findings stress the importance of weight-bearing and joint motion to maintain cartilage structure.
An October 2022 paper from Hiroshima International University, published in the Orthopaedic Journal of Sports Medicine (2) built on this research to examine possible problems related to joint immobilization following ACL reconstruction. Here are their findings:
“(Study) results indicated that immobilization after ACL reconstruction accelerates cartilage degeneration, even when applied only for 2 weeks, and mild exercise during early phases after ACL reconstruction does not facilitate cartilage degeneration. . . . To reduce cartilage degeneration, periods of joint immobilization after ACL reconstruction should be minimized. Mild exercise during the early phases after ACL reconstruction will not negatively affect articular cartilage.”
When bone and tendon are weakened in immobilized knees
Research led by the University of Iowa compared the impact of no immobilization on tendons, immobilization on tendons, and surgically repaired tendons that had been immobilized. The results were published in the Journal of Bone and Joint Surgery🙁3)
- Immobilization had a significant detrimental effect on the bone-tendon complex. (The bone tendon complex is referred to as the “enthesis.” This is where, through various transitions of soft tissue, the tendon sticks to the bone.)
- At two weeks there was a significant decrease in the mechanical properties of the native tendon.
- The immobilized, native tendon remained significantly stronger than the repaired and immobilized tendon.
- However, four weeks of immobilization led to a significant loss of strength of the bone-tendon complex in the native tendon, so much so that it was significantly weaker than the repaired and immobilized tendon. (The native tendon after 4 weeks was weaker than a surgically repaired tendon. Many factors could account for this including healing factors present in the surgically repaired tendon).
Japanese researchers at Hokkaido University Graduate School of Medicine found that complete stress deprivation/immobilization of the patellar tendon induces fibroblast apoptosis – the death of cells that produce reparative collagen in tendons – within 24 hours of casting.(4) Simply, tendons and ligaments need to move, that is how they repair themselves, if immobilized, cells die and tendons die.
Immobilization and the elderly
Immobilization syndrome is not limited to younger patients healing an injury. Inactivity is another, one that can particularly affect the elderly. For example, an activity as simple as walking can nourish the joints in the hips and the knees. Inactivity, on the other hand, can lead to a vicious spiral of disuse, no nourishment to the hip and knee joints, cartilage degeneration, and pain, which leads to even less movement and makes the likelihood of starting an activity even slimmer, resulting in a downward spiral of joint deterioration and pain.
Not surprisingly, it has been shown that the more a specific joint is exercised, the stronger the bone-ligament and bone-tendon complexes become. Exercise specifically helps strengthen the fibro-osseous junction, which is where the ligament/tendon and bone attach to each other.
Movement and gentle range-of-motion exercises improve blood flow to the affected area, removing debris and bringing healing factors. If movement of the joint is painful, isometric exercises, which involve contracting a muscle without moving the affected joint, would be recommended. This is why the RICE treatment protocol is typically used for soft tissue injuries, where R stands for rest and E for elevation, which “spells” immobilization and can be detrimental to healing. Ligaments too are especially sensitive to immobility.
Although immobilization syndrome can be the result of any one of a number of other conditions, injuries are the most common.
If you have questions about immobilization syndrome you can get help and information from our Caring Medical staff.
1 Campbell TM, Reilly K, Laneuville O, Uhthoff H, Trudel G. Bone replaces articular cartilage in the rat knee joint after prolonged immobilization. Bone. 2018 Jan 1;106:42-51. [Google Scholar]
2 Kaneguchi A, Ozawa J, Yamaoka K. Effects of joint immobilization and treadmill exercise on articular cartilage after ACL reconstruction in rats. Orthopaedic Journal of Sports Medicine. 2022 Oct 17;10(10):23259671221123543. [Google Scholar]
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4 Kawabata H, Katsura T, Kondo E, Kitamura N, Miyatake S, Tanabe Y, Setoguchi T, Komiya S, Yasuda K. Stress deprivation from the patellar tendon induces apoptosis of fibroblasts in vivo with activation of mitogen-activated protein kinases. J Biomech. 2009 Nov 13;42(15):2611-5. [Google Scholar]