Calcific tendinitis of the shoulder occurs when calcium crystals deposit within the tendons of the rotator cuff, causing sudden attacks of inflammation. It can be an extremely painful condition, and researchers have been trying to find out exactly why.
A new study published in the Journal of Bone and Joint Surgery reveals how damaged tissue may foster cell, blood vessel and pain receptor growth, possibly causing the painful inflammation associated with the condition.
“We found a three- to eight-fold increase in the number of small blood vessels, nerves and inflammatory cytokines (proteins that direct cell growth) in patients with calcific tendinitis in one of four rotator cuff tendons, as compared to patients with a torn yet normal tendon,” explained Dr. George A.C. Murrell, an Australian orthopaedic surgeon and lead author of the study, as quoted by the American Academy of Orthopaedic Surgeons. “This might explain the chronic inflammation and severe pain that patients with calcific tendinitis often experience.”
The researchers used ultrasound during arthroscopic surgery to identify and remove samples of calcium within the shoulder tendon of 30 patients. Analysis of these samples showed significantly elevated blood vessel growth (neovascularization) and nerve growth (neoinnervation) in patients with calcific tendinitis.
This group also had more frequent pain during sleep and more extreme pain in general.
“This is the first study to show a significant increase in neovascularization and neoinnervation in calcific tendinitis lesions of the shoulder along with an eight-fold increase in mast cells and macrophages,” the authors wrote. “The findings are consistent with the hypothesis that, in calcific tendinitis, the calcific material is inducing a vigorous inflammatory response within the tendon with formation of new blood vessels and nerves.”
Dr. Murrell expressed hope that the results could lead to new ways to manage the pain associated with calcific tendinitis.