The purpose of this report is to demonstrate that radiographic evaluation of the canine shoulder joint alone is not sensitive enough to detect migrated osteochondral fragments within the biceps tendon sheath, as a sequela to osteochondrosis dissecans of the caudal humeral head. A 6-months-old, male, 35 kg Hovawart was referred due to chronic intermittent lameness on the left forelimb. Survey radiographs revealed a semilunar radiolucency surrounded by a moderately sclerotic rim at the caudal aspect of the left humeral head, referred to as osteochondrosis dissecans. However, only computed tomography combined with ultrasonography could clearly confirm a dislodged osteochondral fragment within the left biceps tendon sheath and a consequent tenosynovitis. Arthroscopic treatment on the clinically affected left forelimb followed by an additional approach over the left biceps tendon sheath to remove the migrated fragment resulted in a complete remission of the lameness until the last follow-up one year after surgery. In our opinion, computed tomography should be applied in the medical work up of canine shoulder osteochondrosis (OC) as standard. Combined with ultrasonography, it can further aid in complete evaluation of the shoulder joint and reliable exclusion of displaced osteochondral fragments, which might also be missed during arthroscopy when located too far distally.