The creator of Super Smash Bros. has expressed fears that development on the series' upcoming 3DS and Wii U versions may be affected by his ongoing arm complaint.

Masahiro Sakurai has suffered from pain in his right hand and arm for several months, and now has a full diagnosis.

"I think the one word I've said the most this year, by far, is 'Ow!'" Sakurai wrote in his regular Famitsu column (thanks, Polygon). "Not only am I getting calcific tendinitis, but they've also found what are apparently several ruptures in the muscles.

"My upper arm hurts, and there's this chronic dull pain in my elbow joint as well. On the lower arm, there's this feeling of fatigue around the flexor muscles that turns into pain when I use a keyboard or game controller with my fingers."

Get well soon, Sakurai-san.

Calcific tendinitis is a condition where calcium deposits build up within tendons. It can cause agonising pain.

"There's no instant cure for it," Sakurai explained, "so all I can do is either block the pain with injections or put my arm in a cast to keep the ruptures from spreading. I was told that the important thing was to keep my arm as rested as possible."

Development on Super Smash Bros. Wii U and 3DS is now in full swing. Sakurai is tasked with commanding an army of Nintendo and Namco developers all working on the project.

"As a director, I don't have much time in the weekdays to proceed along with my own work," he explained. "The entire day is spent overseeing other people, holding meetings, working on other proposals, making visits elsewhere and so on.

"If I can get everything squared away, then I can work on my own stuff, but most of the time there's just an overwhelming lack of time. Often I go in on my off-days to catch up on my own work, but with my body going on me like this, I have to cut these extra days out of my schedule and even with that I can't use my right arm very much to control things. If this disorder lingers, or if it never gets fixed, there's no telling what impact that would have on the project."

The cause of calcific tendinitis is currently unknown.

"I've had to control two characters at once in a lot of game projects up to now," Sakurai concluded, "so as long as I keep it to simple moves, this works well enough. It doesn't go that easy with the Nintendo 3DS version, though, and the debug camera is pretty hard to control. Still, now I realise how important it is to have your health. I'm glad I'm still in good enough shape to work."

As with Super Smash Bros. Brawl for Wii, Nintendo announced the series' 3DS and Wii U versions before work began on the project - and Sakurai was again drafted in to oversee production.

Work on the interconnecting games began last year, immediately after the completion of Sakurai's last project, Kid Icarus: Uprising on 3DS. No release dates for the games have been set.