Sorry no, I don't have any suggestions on how to fix that kind of issue, at that age. I'll go ahead and post my thoughts on this tho...
Correcting issues with the feet and legs is very difficult, if not impossible to fix/correct if not done when the keets are very young. At 7 wks old the bones, joints and cartilage are already all well developed, not soft and somewhat still flexible like a young keet's are. Without seeing pics of exactly how the feet on your keet look or seeing how it is walking... it sounds to me like this may be a permanent deformity that the keet may or may not be able to live fine with.
Keep in mind that as the keet matures it may be in considerable pain and possibly have open sores or abrasions develop on it's feet from not being able to walk correctly. And obviously that will cause the bird problems with keeping up with the rest of the flock very well... so the rest of the flock most likely will see that bird as the weak link, and a threat to the flocks' safety. Typically a flock will pick on /chase off, not let the weak link eat/drink as much as it needs to, exclude it from being part of the flock etc. The birds that can't keep up or aren't allowed to be part of the flock are usually the first to be taken by predators. When Guineas are in pain or have some sort of deformity or disability it more often than not results in failure to thrive/stunted growth/lack of heartiness of the effected bird. If the bird is in pain, suffering and/or miserable and not thriving like the rest of the flock is I'd put it down. If it's doing fine in the flock then watch it and see how it does within the flock as everybody matures... but prepare yourself for that bird to be taken by a predator and for the fact that you will need to put the bird down if it's not doing well/is in pain.
And one last thought... I'm not sure what the injuries were to cause the keet to hock walk at 11 days old, but if it just happened all of a sudden in the brooder one day and you weren't there to witness what caused it... it could be a genetic issue you wouldn't want to pass on to more offspring.