The tendons of the front legs of newborn calves are often tight. Because the calves are unable to stretch their legs in the womb, the tendons don't stretch.
Generally as the calves begin to use their legs and put weight on their hooves, the tendons stretch to normal length.
If the calf is unable to walk properly splints can be applied to the legs until the tendons stretch.
You can also hold the calf upright so it can place its hooves on the ground. As you lower the calf a bit the body weight will slowly stretch the tendons. Hold the calf so its legs can bear the body weight. You may have to do this several times for a few days.
I believe your calves' problem is hereditary. Unfortunately a hereditary or genetic problem is serious.
It is serious in that you can't cure the affected calves.
There is testing available to determine which animals have the genes which cause the frozen joint problem. This testing can determine which animals can be bred.
What is the breed of your cows?
Have the cows been bred to the same bull this year?
Please excuse me. I have a call that will take me away from the computer for a while. I will reply when I return.
If you don't have lupine in your pastures, then the problem is hereditary.
The problem occurs in calves which are homozygous recessive. Affected calves get a recessive gene from the bull and from the cow.
The existence of the problem indicates you have cows that are carriers. If they are bred to carrier bulls, their calves will be affected. If they are bred to bulls that are not carriers, no calves will have the problem.
Any bulls or replacement bulls that are tested and found to be carriers should not be allowed to breed your cows.
Dr. Jonathan Beever at the University of Illinois (firstname.lastname@example.org) has researched this problem.