Calcific tendinitis is a condition characterized by the deposition of calcium hydroxyapatite crystals within tendons, most commonly affecting the rotator cuff tendons of the shoulder. While it can occur in other tendons, such as the Achilles tendon, gluteal tendons, or wrist extensors, the shoulder is by far the most frequent site. The condition is often self-limiting, with episodes of pain that can range from mild to extremely severe, followed by spontaneous resolution of the calcifications.
Etiology and Pathophysiology The exact cause (etiology) of calcific tendinitis remains largely unknown, and it is generally considered an idiopathic condition. It is not typically associated with systemic calcium metabolic disorders (like hyperparathyroidism) or trauma, though mechanical factors and localized tissue stress may play a role. Theories regarding its development include:
- Localized Hypoxia: Reduced blood supply to a specific area of the tendon may lead to a change in cell type (metaplasia) from tenocytes (tendon cells) to chondrocytes (cartilage-like cells), which are then capable of forming calcium deposits.
- Genetic Predisposition: Some individuals may have a genetic susceptibility to developing the condition.
- Metabolic Factors: While not a direct cause, an association with conditions like diabetes mellitus and thyroid disorders has been observed in some studies.
The pathophysiology typically progresses through several stages:
- Precalcific Stage: Tendon cells in a specific area undergo metaplasia, transforming into chondrocytes that are capable of calcification. This stage is usually asymptomatic.
- Calcific Stage:
- Formative Phase: Calcium crystals are actively deposited within the tendon. The calcification is often dense and well-defined. Pain may be mild or absent during this phase.
- Resorptive Phase: This is often the most painful stage. The body attempts to resorb the calcium deposits, leading to an inflammatory response. Macrophages and giant cells surround the deposits, causing significant pain and swelling. The calcification may appear less dense and more "cloud-like" on imaging as it breaks down.
- Postcalcific Stage: The calcium deposits are fully resorbed, and the tendon tissue begins to remodel and heal. Pain typically resolves, and tendon function is restored.
Clinical Presentation Calcific tendinitis most commonly affects individuals between 30 and 60 years of age. While it can be an incidental finding on imaging in asymptomatic individuals, symptomatic cases often present with:
- Pain: The most common symptom, ranging from chronic, dull ache to sudden, excruciating pain, especially during the resorptive phase. Pain often worsens with activity, particularly overhead movements, and can be severe at night, disturbing sleep.
- Limited Range of Motion: Pain can restrict shoulder movement, particularly abduction (lifting the arm away from the body) and rotation.
- Tenderness: The affected area of the tendon may be tender to palpation.
- Stiffness: A feeling of stiffness in the affected joint.
Diagnosis Diagnosis of calcific tendinitis relies on clinical evaluation combined with imaging studies:
- Clinical History and Physical Examination: A detailed history of pain characteristics and a physical examination assessing range of motion, strength, and tenderness can suggest the diagnosis.
- X-ray: Plain radiographs are typically the initial imaging modality. They can clearly visualize calcium deposits within the soft tissues of the tendon, including their size, shape, and location.
- Ultrasound: Ultrasound is highly effective for identifying and characterizing calcium deposits, assessing their size, morphology, and vascularity. It is also useful for guiding interventions like needle lavage.
- Magnetic Resonance Imaging (MRI): While not as good as X-ray or ultrasound for directly visualizing calcium, MRI can help rule out other shoulder pathologies (e.g., rotator cuff tears) and assess associated inflammation or tendon integrity.
Treatment Treatment strategies aim to alleviate pain, restore function, and encourage the resolution of calcium deposits. Options range from conservative measures to minimally invasive procedures and, in rare cases, surgery.
Conservative Management:
- Rest and Activity Modification: Avoiding aggravating activities.
- Non-steroidal Anti-inflammatory Drugs (NSAIDs): Oral NSAIDs are often prescribed to reduce pain and inflammation, particularly during acute flare-ups.
- Physical Therapy: Once acute pain subsides, exercises focusing on restoring range of motion, strengthening rotator cuff muscles, and improving scapular mechanics can be beneficial.
- Heat/Cold Therapy: Application of heat or ice packs can help manage pain.
- Corticosteroid Injections: Injections of corticosteroids (often combined with a local anesthetic) into the subacromial bursa (the space above the rotator cuff) can provide temporary pain relief by reducing inflammation, but they do not directly remove the calcium.
Minimally Invasive Procedures:
- Needle Lavage (Barbotage): Performed under ultrasound guidance, this procedure involves inserting one or two needles into the calcium deposit to break it up and aspirate the calcific material. It is often combined with a corticosteroid injection.
- Extracorporeal Shockwave Therapy (ESWT): This non-invasive technique uses acoustic shockwaves to fragment the calcium deposits and stimulate a healing response in the tendon. It can be performed with varying energy levels (low, medium, high).
- Percutaneous Ultrasonic Tenotomy (e.g., Tenex): This procedure uses a specialized needle with an ultrasonic tip to precisely break down and remove the calcific deposits while sparing surrounding healthy tissue.
Surgical Management:
- Arthroscopic Calcium Excision: If conservative and minimally invasive treatments fail to provide adequate relief, surgical removal of the calcium deposits can be performed using an arthroscope (a small camera inserted through tiny incisions). This procedure is highly effective but reserved for persistent cases.
Prognosis The prognosis for calcific tendinitis is generally good. The condition is often self-limiting, with spontaneous resorption of the calcium deposits occurring over a period of months to years in many cases, even without intervention. However, the symptomatic phases can be very painful and debilitating. With appropriate management, the vast majority of individuals experience significant pain relief and functional improvement. Recurrence after successful treatment is uncommon.