The purpose of this report was to clarify the pathogeresis of the primary osteoarthritis (OA) of the shoulder. OA of the shoulder is characterized by osteophyte, sclerosis, irregularity and narrowing in the glenohumeral joint, which has no traum and the wide acromio-humeral interval (AHI) (AHI≥5mm). For research of the polyarticular OA, elbows, wrists, fingers and knees werw examined radiologically.
Chondrocalcinosis (CC) is characterized by the calcific deposite in the meniscus of the knee. Patients were composed of 30 cases 46 shoulders (both side 16 cases, right side 5 cases, left side 9 cases). One case was male and 29 cases were females. Their average age was 79.2.
Radiologically, OA of the shoulder was divided into 2 types. Smooth type (29 shoulders) showed a smooth subchondral bone of the humeral head. Irregular type (17 shoulders) showed an irregular subchondral bone of the humeral head. In the elbow or wrist joints, 6 cases (32%) of 19 cases were associated with OA. In the finger joints, 9 cases (43%) of 21 cases were associated with OA. In the knee joints, 16 cases (70%) of 23 cases were associated with OA. Most of cases had polyarticular OA. On the other hand, 5 cases (22%) of 23 cases had OA only in the shoulder joint. Eight cases (32%) of 25 cases were associated with CC.
It is possible that OA of the shoulder is not caused by overuse of the upper extremities, but caused by constitutional disease. Most OAs of the shoulder have some relationship to polyarticular OA. a minority group may have a different pathogenesis from polyarticular OA.
