Locking stifle and strange lameness?

[Delta99]

Have had an ex racer on loan for about a month now, he had about a month of coming back into work before I had him after a year off with a tendon injury.
Twice now I have seen what I assume is 'locking stifle', once I was picking out his foot and he seemed unable to flex the leg (it seemed completely stuck!) and the second time he turned but seemed to pivot around the hind leg without bending it. Does that sound about right? I think it's due to the lack of fitness and muscle but just wondered if I should be concerned about it? Will it cause him more problems later on in life or in the winter? Is it likely to deteriorate?
He also nods his head when I rise on one diagonal, could this be related to it? He only does this under saddle, not on the lunge. It again seems like a weakness somewhere, I'm fairly certain it's not caused by anything in the leg/foot. Would a chiro or physio help with it? Or is it something I should be very concerned about?

 

[Booboos]

There are two kinds of problems that can cause a locking stifle:

Muscle weakness: this occurs fairly often in young horses and is resolved with more work

OCD: this is much more serious and requires surgery and rest.

I would call the vet out for a full lameness work-up and he can advise on the front lameness (which sounds like a back or hind leg problem to me. If it is the hind leg it fits in with the OCD, but the best thing to do is ask the vet for a diagnosis).

 

[DuckToller]

My last horse had an upwardly fixating stifle (ie locking). Your description sounds about right - picking out the hoof of the affected leg was always tricky. In the end I didn't pick it up off the floor, I just got him to lift the heel and rest the weight on the toe (like when he is resting one hindleg) as I picked it out, always making sure I stood to the side.

Getting him shod was interesting, but once the farrier got him sussed he would just be careful of the angle of the leg and again it was fine.

With regular work, particularly lunging and hillwork, my horse grew out of it. He is now Grade A show jumper, (sadly not mine anymore) so it didn't affect him in the long run! If you are prepared to put the work in to build up the muscles, he should get better to the point where it hardly ever happens.

Not sure if the head nodding is related, so maybe get that checked out.