4.1 Goals of Procedure

Calcific tendinitis, characterized by the formation of calcium deposits within the rotator cuff tendons, occurs in up to 20% of adults. ¹ The disease has been found to occur more frequently in patients between ages 50 and 60 years, with a predilection in sedentary workers and females. ² While the etiology of this disease process is not entirely understood, the pathogenesis of calcification is cyclical in nature, beginning with cell-mediated fibrocartilaginous metaplasia, progressing to calcification of the tendon, and, finally, resorption. Pain is most severe in the resorptive phase. ³ This is in contrast to insertional calcification at the bone–tendon junction, such as what occurs in other anatomical areas including the Achilles–calcaneus interface. ⁴ Calcium deposits, consisting of hydroxyapatite crystals, are found in the supraspinatus tendon in 50% of cases and commonly extend into the infraspinatus, but are rarely found in the subscapularis or teres minor tendons of the rotator cuff. ⁵

While acute pain is the most common clinical manifestation, calcific tendinitis is also associated with muscle spasms, bursitis, inflammation of the long head of the biceps, and acute or gradual restriction of movement. ⁶ Twenty percent of cases are found incidentally in asymptomatic patients. ⁷ Although calcific tendinitis may resolve on its own, repeated episodes may warrant specific treatment to manage pain.

The management of calcific tendinitis may consist of both nonoperative and operative treatments, depending on the patient’s age, activity level, and symptoms. Nonoperative options are almost always the first line of treatment. These treatments can include activity modification, physical therapy including range-of-motion exercises, cryotherapy, and nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief. Other nonoperative treatments, including extracorporeal shock wave therapy (ECSW) and needling with/without steroid injections, have also been described. ECSW has been shown to have some short-term symptomatic improvement in some studies, but is dose dependent and can be accompanied by bone marrow edema and humeral head necrosis. ⁸ Ultrasound-guided needle lavage is another described minimally invasive technique aimed at decompressing the deposits to reduce pain. ⁹ The use of a corticosteroid injection following the needling process has been shown to improve results; however, when used alone, it is generally short acting and may be contraindicated in patient populations with medical history of insulin resistance, immunosuppression, and high blood pressure. ¹⁰ If nonoperative treatment options fail, surgical intervention in the form of an arthroscopic debridement can be attempted. The overall goal of arthroscopic treatment of calcific tendinitis is to reduce pain and improve function.

4.2 Advantages of Arthroscopic Management

While nonoperative treatments as described earlier may be successful for the majority of patients, in some cases, symptoms persist and surgical intervention is necessary. Arthroscopic debridement has been shown to provide excellent results in unresponsive or worsening cases. ¹¹ In comparison to ECSW and ultrasound-guided needle lavage, surgical management provides direct visualization of the lesion as well as complete breakdown of the deposit. While nonsurgical treatments such as ECSW and ultrasound-guided needle lavage are less invasive, they may not provide complete removal of deposit when compared with surgery. Notably, while open surgery can be performed, this approach is typically unnecessary as complete deposit removal is not essential and can cause iatrogenic damage to the tendon.

Several clinical investigations have highlighted favorable clinical outcome measures associated with arthroscopic surgery for calcific tendonitis. In a cohort of 23 patients who had failed at least 1 year of nonoperative management, Ark et al demonstrated that arthroscopic calcium removal and concomitant subacromial bursectomy produced results graded as good (full motion and complete pain relief) in 50% of patients and satisfactory (full motion and occasional episodes of pain) in 41% of patients at average follow-up of over 2 years. ¹² In an investigation by Seil et al, 54 patients with calcific tendinitis of the supraspinatus tendon underwent arthroscopic removal of the calcific deposits. Clinical follow-up at 2 years showed significant improvement in shoulder function according to the Constant score, 32.8 points (±19.8) preoperatively and 90.9 (±13.0) postoperatively (p < 0.001), as well as 92% patient satisfaction with the overall outcome. ¹³ Additionally, Maier et al conducted a therapeutic case series with 99 patients who underwent arthroscopic removal of rotator cuff calcific deposits with preservation of the integrity of the rotator cuff. Good to excellent results were reported in 90% of patients measured by the Constant score (overall mean CS_abs = 88.8 points (±10.4); CS_rel = 99.0% [±3.7]; p< 0.05) at average follow-up of 37 months and avoided iatrogenic tendon defects in all patients. Overall, the literature clearly demonstrates improved short- and long-term postoperative clinical outcome measures after arthroscopic intervention for calcific tendonitis. ^{11 – 18}

4.3 Indications

Calcific tendinitis has been well reported in the literature. Indications for surgery are widely dependent on symptom involvement, although there is no clearly defined time period for when surgery should be performed ( Table 4.1 ). Patients are best indicated for arthroscopic treatment of calcific tendinitis after failure of nonoperative management. Failure of nonoperative therapy is typically defined by the persistence of symptomatic calcific tendinitis of the shoulder after a minimum of 6 months. ¹⁹ Physical examination findings may be variable due to the severity of the disease and any associated pain at the time of the examination. The following radiographic classification system described by Mole et al is commonly used to classify these lesions ²⁰ :

• 
  

  Type A: sharply delineated, dense, and homogeneous.

  
  
• 
  

  Type B: sharply delineated and dense in appearance, with multiple fragments.

  
  
• 
  

  Type C: heterogeneous in appearance, with a fluffy deposit.

  
  
• 
  

  Type D: dystrophic calcifications at the tendon insertion.

Calcific deposits can be visualized as a single localized deposit, several localized deposits, or one large deposit consisting of several compartments. ¹¹ Each compartment or localized deposit can require separate release during surgery for complete evacuation of symptomatic deposits. Preoperative advanced imaging with MRI can also be helpful as this modality can detect partial- or full-thickness rotator cuff tears as well as other concomitant pathologies. An example of a calcific deposit in the anteroposterior view is shown in Fig. 4.1 . Notably, in the presence of calcifications, shadows visible on imaging may cause false-positive and false-negative findings. ²⁵