I was thinking about this when I was reading about English bulldogs and other breeds prone to these conditions.

*Bowed Legs*

Instead of the legs being normally straight, they curve outwards. Lions can still hunt, as this actually helps them to run faster. However, they're more likely to get joint osteoarthritis later as they get older. This can decrease the speed and stamina of your lion. If the arthritis gets really bad, your lion will be unable to hunt/patrol or is limited significantly.

*Patellar Luxation*

This condition causes the patella, the outer knee joint, to constantly pop in and out on random occasions. Luxations can be from Grade 1 - Grade 4.

Grade 1: No pain, rare occurrence
Grade 2: Slight pain, uncommon
Grade 3: Mild pain, more common
Grade 4: Severe pain, extremely frequent

If your lions are hunting/patrolling, These occurrences, based on the grade, can possibly cause futhur injury or even lead to death in rare occasions ( eg fall into a pit and breaks legs, twist ankle, etc.,)