Our vet/chiropractor was out today to see how Red's healing from his injuries in coming along. The answer is that it is coming along, although slowly, as is often the case with soft tissue injuries. Now that the swelling in his hock is pretty much gone, it's possible to feel (although really not see) that there is a bit of residual swelling along the lower end of the Achilles tendon just above the point of hock, and the point of the hock itself is very slightly swollen to the touch (not visible to the eye). Here's the anatomy of the hock - the Achilles tendon is part of the structure labeled tendon of gartrocnemius (top right) in the diagram:
He also has just the slightest bit of remaining sensitivity of his inner sesamoid ligament - the very short ligament under the sesamoid bone which attachs it to the pastern bone. His walking downhill is much improved, although on a steeper hill he will drag the left hind toe and tend to break over at the pastern joint more quickly. When moving on the level he also tends to preferentially slightly weight the outer side of his left hind hoof. All of these behaviors, as well as his being more off when trotting to the right on the lunge, are consistent with the remaining areas of slight soreness. The tightness in his hindquarter muscles is now gone. It's likely that all this is the result of the original injury when he stepped in a hole in the arena and almost fell with me. The subsequent kick to the outer hock, while resulting in ugly swelling and cellulitis, probably didn't make anything worse.
Here are two diagrams that shows the location of the sesamoidean ligaments - which run from the underside of the sesamoids - the pair of bones protruding from the back of the pastern joint, to each side, and covered by the suspensory ligaments. For some reason the first diagram omits the suspensory ligaments.
So we're to continue on track with our rehab - continuing daily turnout, since he's careful to protect the injuries in the way he moves at walk, trot and canter, and the use of the leg should result in stronger (although some slower) healing, some icing of the two remaining slightly sore areas - the rebound of blood to the area after icing should aid healing - rubbing in arnica gel, and what we've come to call "pasture patrol" - hand walking around our pastures and up and down their hills. Every week or so, I'll stick him on the lunge for a few minutes to see how things are coming. No riding until everything seems to be healed up, which could be several more weeks or perhaps even a month or more.
It's been about 5 1/2 weeks, and I hope to be enjoying riding Red for many years to come, so a couple more weeks, or even longer, won't be too hard for either one of us. These sorts of injuries can be very persistant and slow to heal, and although to many eyes Red would appear to be only slightly lame, it's advisable to take our rehab slowly.