What is Enthesopathies?
Entheses are the points where our tendons and ligaments attach to our bones. When these points get diseased, we refer to these conditions as enthesopathies. While experts have some debates around this, generally, they agree there are two types of entheses: fibrous and fibrocartilaginous. The key difference lies in how they connect to the bone. Fibrous entheses attach directly onto the bone’s outer covering called the periosteum, while fibrocartilaginous ones do not have this periosteum layer.
Generally, these attachment points (entheses) are found outside the areas where bones meet (joints) but there are some exceptions like the sacroiliac (between the spine and hip), sternoclavicular (between breastbone and collarbone), and distal interphalangeal joints (found at the tips of fingers and toes). They have two main functions: to provide stability to the joint, and to transfer physical forces. Uniquely, these attachment sites (entheses) also have very little blood supply.
Enthesitis, a type of enthesopathy, is when these points where tendons and ligaments attach to our bones become inflamed. It is often linked with wide-spread inflammatory conditions such as psoriatic arthritis (a type of arthritis that affects some people who have psoriasis) and spondyloarthropathies (a family of long-term diseases of joints).
What Causes Enthesopathies?
Enthesopathies, or disorders relating to the places where tendons or ligaments attach to the bones, can be divided into two main groups: 1) those caused by repetitive physical stress, and 2) those resulting from widespread inflammation.
The first type, connected with repetitive stress, is commonly seen in sports-related injuries. Examples include lateral and medial epicondylitis (tennis or golfer’s elbow), and Achilles and shoulder enthesopathy (disorders associated with the regions where tendons attach to the heel bone and shoulder joint).
The second type results from a wide-ranging inflammatory response and tends to affect multiple entheses (sites of attachment between tendons or ligaments and bone). This is often due to small, repetitive injuries that allow natural defense cells of our body to invade the area and lead to inflammation, signaled by substances called chemokines.
Chemokines involved in this inflammation response are CXCL1, CCL2, interleukin (IL)-17, tumor necrosis factor (TNF)-alpha, and prostaglandin E2 (PGE2) – these are proteins and hormones that serve as signals in the body to summon immune cells to injury sites, fighting off infection or helping with recovery.
Risk Factors and Frequency for Enthesopathies
The occurence and new cases of enthesopathies, which are diseases affecting the points where tendons or ligaments attach to bones, can be challenging to measure due to their diverse nature, symptoms, and causes. It’s been reported that about 35% of patients with Psoriasis Arthritis (PsA) are also affected by enthesopathies. For patients diagnosed with Spondyloarthritis (SpA), which is a type of arthritis, the rate of enthesopathies ranges from 10% to 60%.
Signs and Symptoms of Enthesopathies
Enthesopathies, or disorders affecting the connective tissues where ligaments and tendons attach to bones, can cause a range of symptoms depending on where they occur in the body. Common symptoms include pain and a decrease in movement in the affected area. If you examine the area, it might show signs of swelling or redness. You may also feel pain when touching the affected area or moving the connected joint. To assess mobility issues and determine the extent of pain, both self-initiated and externally assisted movement should be tested.
If a widespread inflammatory disease is thought to be the cause, more extensive checks should be carried out. This should include looking at areas often impacted such as the joints between the spine and pelvis, the tendon connecting the heel to the calf muscle, and the joints at the tips of your fingers and toes. Asking broad questions about other symptoms can give clues to the root cause of the inflammation of the connective tissue. These symptoms could include things like weight loss, night sweats, chills, or other general signs of illness.
Testing for Enthesopathies
If your doctor suspects you have enthesopathy, a condition where the point where your tendon or ligament attaches to your bone becomes inflamed or painful, they’ll first conduct a thorough look into your medical history and perform a physical examination. This process will vary depending on the cause of the enthesopathy.
If your enthesopathy is likely due to overuse and there’s little chance it’s caused by an underlying inflammatory disease, your doctor will mostly rely on a physical examination. If needed, they might also use imaging tools to get a better look at what’s happening inside your body. X-rays can show whether there are problems with bone or if any mineral deposits have built up at the site. If they need to see soft tissues, like the enthesis (the spot where your tendon or ligament attaches to your bone), they might use an ultrasound or magnetic resonance imaging (MRI).
For enthesopathies that might be due to an overall inflammatory response which leads to swelling and pain at the enthesis, known as enthesitis, your doctor might need additional tests. These could include a complete blood count, checking for HLA-B27 to test for seronegative SpA (an umbrella term for types of arthritis that don’t test positive for rheumatoid factor), rheumatoid factor, anti-nuclear antibody, and various other factors associated with autoimmune disease. These tests can help pinpoint the underlying cause. Like before, your doctor might also order imaging studies if necessary for a clearer picture of your condition.
Treatment Options for Enthesopathies
Enthesopathies, or injuries involving the areas where tendons or ligaments connect to bones, can be caused by various factors, so the treatment depends on the specific root cause. If the enthesopathy is simply due to excessive use, standard treatments include cold packs, rest, and anti-inflammatory medications, usually for about a week to 10 days. Some controversy exists around the use of these medications in the early stages of recovery, as they might slow down healing by reducing inflammation, which is part of the body’s natural response to injury.
Additional therapies often used for enthesopathies include physical therapy, steroid injections, topical nitrate treatments, and platelet-rich plasma (PRP) therapy. Physical therapy is a proven method to improve pain, increase movement, and improve overall function. From a biomechanical point of view, different types of exercises may relieve stress on the tendon and promote healing.
The use of steroid injections in treating enthesopathies is slightly controversial. Despite their common use in medical practice, it’s not clear whether they actually provide significant benefits. Also, injecting steroids directly into a tendon might even result in further injury.
Applying topical nitrates is thought to increase the growth of new blood vessels, stimulate the activity of fibroblast cells involved in tissue repair, and enhance collagen synthesis. Nitroglycerin patches show promising results as a potential additional treatment for chronic tendon disorders, apart from traditional treatments.
PRP therapy involves introducing a concentrated solution of growth factors into the body, which establishes an environment that promotes healing by attracting additional cells and growth factors. While still being researched, studies have suggested that PRP could be beneficial for a variety of enthesopathies.
In the case of calcifying enthesopathies, where calcium deposits build up in the tendons and ligaments, a procedure known as barbotage can be used. Under ultrasound or x-ray guidance, a doctor will repeatedly inject and then remove a saline solution into the calcified area. This procedure has been shown to be successful in treating specific types of enthesopathies.
Enthesopathies caused by systemic inflammatory diseases may be managed with disease-modifying antirheumatic drugs (DMARDs), such as methotrexate or hydroxychloroquine. Other treatments include biologic medications like rituximab, etanercept, and infliximab, which work to reduce inflammation and help decrease the overall progression of the disease.
What else can Enthesopathies be?
When doctors are trying to identify enthesopathies (conditions affecting the areas where tendons and ligaments meet bone), they will consider several other conditions that might be causing the symptoms. They can include:
- Injuries that involve tissue being torn away from a bone (avulsions)
- Fractures (broken bones)
- Rupture of a ligament or tendon (tissues that connect bones and muscles)
- Localized infection (an infection in just one area)
- Contusions (bruises)
- Muscle strains (injuries from overstretching a muscle)
- Malignancy (cancer)
What to expect with Enthesopathies
The outlook for conditions called enthesopathies, which affect the points where tendons and ligaments attach to the bones, is usually quite good, if the reasons causing them are found. If appropriate rest and rehabilitation are provided, most people with enthesopathies get better within 2 to 4 weeks.
However, if the enthesopathies are caused by a widespread inflamed condition, the recovery might take longer. This depends on how severe the underlying condition is and what’s causing it.
Possible Complications When Diagnosed with Enthesopathies
A tendon or ligament tear can occur as a result of two main factors. These are consistent overuse of the tendon or ligament, and widespread inflammation disorders affecting where tendons or ligaments attach to the bone. This can lead to complications in both cases.
Preventing Enthesopathies
Patients who first present with enthesopathies (conditions affecting the linkage between tendons or ligaments and bone), may be seen by different types of specialist doctors. It is important for the doctor to understand the patient’s condition well, in order to refer them to the right specialist. If the enthesopathy is localized and caused by repetitive usage, the patient can be educated on managing the condition either at the doctor’s clinic or with a professional physical or occupational therapist.
Patients are often advised on how to protect their joints in order to avoid further damage from overused enthesopathies. If the enthesopathy is due to a systemic inflammatory disease (a condition that often affects many parts of the body), a more detailed and comprehensive approach to patient education may be necessary. These patients may need to have discussions with a variety of specialist doctors, such as physiatrists (rehabilitation medicine specialists), rheumatologists (experts in joint diseases), internal medicine doctors, and immunologists (specialists in immune system disorders). This will ensure the patient is adequately educated and receives the correct treatment for their specific condition.
