The acromioclavicular joint(ACJ) is a common site of shoulder-related pain and is often associated with subacromial impingement syndrome. We reported on the arthroscopic operation and the open resection of distal clavicle were effective procedures for acromioclavicular osteoarthritis with cuff tendinopathy. The purpose of this study was to evaluate the histological pattern of osteoarthritic cartilage of ACJ. Between October 2002 and September 2004, this study involved 23 shoulders in 23 patients: 13 men,10 women. The average age at the time of surgery was 60.2 years old (range,45-70 years old). We stained them with hematoxylin and eosin. HE sections of the,23 shoulders were graded according to the modified Mankin's structure system (grade0: normal, gradel: surface irregularities, grade2: clefts to transitional or radial zone, grade3: clefts to calcified zone, grade4: no cartilage layer or complete disorganization). Safranin O sections were graded according to Mankin's system(grade0: normal, gradel: slight reduction, grade2: moderate reduction, grade3: severe reduction, grade4: no dye noted). The grading of the HE staining showed grade0: 11specimens, grade1: 31 specimens, grade2: 35 specimens, grade3: 25 specimens, grade4: 36 specimens. The grading of the safranin O showed grade0: 8 specimens, grade1: 21 specimens, grade2: 20 specimens, grade3: 42specimens, grade4: 47 specimens. This histological examination of these ACJ demonstrated the variation in the osteoarthritic changes in the cartilage.
