a two year old is long out of the puppy stage .
muscle supports ligaments . muscle requires good protein.
the leg is not smooth , there is a bump at the carpus and a bowed effect at the radius or front bone of the forelimb , so there may have been some inflammation at a growth period as you would have with H O D . If the animal was out of sorts , had a bit of a temperature, was super picky about eating , and was sensitive to the leg being squeezed in that area , or careful with itself , as in pano but not shifting those would have been indications. Minor . Some are terribly disforming . During this the pup would have roached his back to distribute the weight . The hocks would have compensated with becoming cow hocked . There is only one picture of the dog standing sideways and here he shows the hocks well under , picture 4 and in picture 3 walking away the hocks are close and parallel to each other , looking a bit on the weak side whereas in the walk one should be going to mid and the other pushing outward . It may just be the step sequence caught by the camera, or think of a supported bunny hop type movement.
I would think some anti inflammatory might be good for the dog and something to support ligament and cartilage . MSM , probiotics , whole vitamin C , micro and trace minerals. These are all in the arsenal of Great Dane breeders where this H O D in not uncommon.
Inflammation could have been from a virus or vaccination , a vaccine mediated immune response. The Purdue Vaccination Studies and Auto-antibodies | Dogs Naturally Magazine
If you want to see for yourself , when you have the dog x rayed for hips and elbows do the pastern - carpus ( wrist )area also . If there has been inflammation there will be a cuff .