All captive orca males have collapsed or bent dorsal fins, even some captive female orcas have the condition too. In the wild, dorsal fin collapse is very rare and less than 1% of all wild orcas have dorsal fin collapse.

A male killer whale's dorsal fin can grow to as much as 6 feet tall. Despite the fact that the dorsal fin is very straight, it is not supported by bone, but a fibrous connective tissue called collagen. A wild orca often travels far, and quickly, in deep water. The water provides pressure to the fin, keeping the tissues inside healthy and straight, and encouraging the dorsal fin to remain straight.

In captivity, dorsal fin collapse may be related to several factors, including time spent at the water surface (gravity takes over) and swimming in the same direction in a relatively small pool. The tissue in the dorsal fin gets less of a workout, and less support in the water than it would in a wild whale, and starts to fall over. The same thing can happen to the whale's tail flukes, which often flop over at the ends. Other causes may be dehydration due to warmer water and air temperatures, stress, age or genetics.

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That said, it is not impossible for a wild orca's dorsal fin to collapse or become bent. The number of wild male killer whales with abnormal dorsal fins appears to vary from population to population. (More information on In the wild)

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Part of the caption/provided information from @inherentwild (on IG)