Yes mine had his coffins injected at the end of November. It helped tremendously. He's since had Tildren which has helped even more, but he does have issues with not only his coffin joints, but hocks too. He's now back in work and feeling great!
Mine had his coffin joints injected last April - massively helped my horse with a combination of box rest at the time. Luckily I didn't need the tildren at the time as he came sound, but still have it as an option now if his issues resurface!! good luck