We wish to present a rare case of painful throwing shoulder accompanied by a glenoid osteocndral injury. A 31-year-old male complained of left shoulder pain when throwing. He had participated on a non-professional baseball team as a pitcher. His dominant shoulder was the left one. He had complained of pain during the cocking-up phase when he was a 20-year-old. He had no symptoms in daily life, so he felt pain. He visited our hospital when he was a 31-year-old, as he began to feel pain in daily life after throwing through a whole game. Although ROM limitations were not detected, posterior shoulder pain occurred at abduction. Crank test was positive. MRI study showed a SLAP lesion type II, cartilage injury of the humeral head like PLN, internal impingement at the ABER position and a slit-shaped contrast medium invasion into the glenoid fossa at the 10 o'clock level. Conservative treatment was not effective. An arthroscopic surgery was carried out. The arthroscopic findings were similar to MRA study. The labrum was repaired and thermal shrinkage of the anterior capsule and debridement of the SSP were carried out. There were some reports concerning the glenoid osteochondral damage. However, a report concerning a non-traumatic groove-shaped cartilage damage is quite rare. We think that this injury is connected to the shearing force to the fossa and anterior instability of the shoulder. We would like to examine the cause of the defect in future.
