Abstract
Calcium pyrophosphate dihydrate (CPPD) crystal deposition into fibrocartilage and hyaline cartilage was a well recognized condition that sometimes caused acute arthritic attack. We found five patients who had evidence of CPPD crystal deposition in tendon proper during histopathologic examination of 118 consecutive cases with rotator cuff tears.
The patients were 4 women and 1 man with an average age of 71.2 years old (range, 65-82 years old). The average duration of symptoms before surgical intervention was 11.6 months (range, 5-36 months). There was 1 partial-thickness tear and 4 full-thickness tears (1 small, 1 medium, and 2 large tears). None of the patients had an obvious traumatic event. These cases were studied clinicopathologically. Radiographically, abnormal deposits were demonstrated at the distal insertion of the rotator cuff as linear or punctuate lesions in all cases. In surgical observation, white chalk-like deposits were macroscopically seen at the stump of torn tendons. In pathological examination, characteristic rhomboid-shaped crystals with positive birefringence under polarized light were identified as CPPD in torn tendon tissues and easily distinguished from dystrophic calcification histologically. Neither distinct inflammatory nor granulomatous changes were observed at the tendon tissues around CPPD crystal deposition. CPPD crystal deposition into torn tendons was considered to be 1 of degenerative processes because of the absence of inflammatory and granulomatous changes. Deposition of CPPD in torn tendons may be associated to the vulnerability of tendon fibers.
