Hey! I feel that the posters that have responded to you in SQSA haven't really addressed whether or not Medicham is viable in OU.
It's ability, Pure Power, give is one of the strongest Hi Jump Kicks in the game, while its Psychic-typing can provide an interesting niche. Overall though, Medicham is quite weak to Ghost-type Pokemon, specifically Gengar and Jellicent, who can go for the OHKO or Will-O-Wisp, respectively. If you feel that your team can adequately take on Medicham and cover its weaknesses, it may be worth considering! However, I would almost always recommend either Terrakion or Mienshao over Medicham. The former still hits like a truck while running an acceptable speed, while Mienshao can add longevity to the match through scouting and hitting hard with HJK. I hope this helps answer your question in conjunction with the answers provided in SQSA. Feel free to contact me if you ever have more questions =D!