reconstructed collarbone and pack straps

I broke my collarbone in the 8th grade, but not as severely. I fear until he finds a pack he can tolerate, backpacking won't be any fun for him. It isn't like an S strap will help if his issue is the repaired area of his collarbone. The plates and screws will always irritate his skin when any sort of strap crosses over them.

If I was faced with such an impediment after having discovered a love for backpacking, I'd try all sorts of things to pad the plates, as I can only imagine it is the rubbing across the plates that causes the problem. Towels placed under the straps. Large pieces of blue closed cell pad under the straps(likely very hot and sweaty).

Perhaps the packs he has used or tried on are not fitted properly. There is supposed to be 2 fingers of gap between the strap and the top of the shoulder. That might not help where the strap crosses the collarbone, but it's a place to start.

I'd experiment with some strips of padding attached to the shoulder strap so they lay along each side of the bone (parallel to the bone, which would be roughly perpendicular to the shoulder strap). The idea is to raise the shoulder strap so it passes over the bone without putting pressure on it, or even touching it if that's necessary.

I did something like that to help a hiker in my group who had a bad boot bruising her leg just above the ankle. I made two little rolls of gauze and taped them on either side of the tendon above the ankle bone so that the collar of the boot pushed on those instead of the tendon. Worked like a charm.

Those might do the trick if you cut the middle out of them so there's a slot for the collar bone to go through.

I’ve had the same thought. My wife has a protruding collarbone on her right shoulder. It’s from birth, and gives her trouble backpacking. I’ve thought about getting her a Seek Outside external, but I’m not really certain it would make any difference. Really, most current internal frame packs are just external frames cleverly disguised as internals. The frames are fixed (stays are not customizable), and are essentially on the outside of the pack. They basically act like an external (as long as they are appropriately sized to the wearer).

I did make a lambswool cushion for my wife. I cut a piece to size and sewed on a 2” wide piece of Velcro to secure it. It really helps. I’m going to order the Zpacks set I linked above and see how those do too.

Since (because of my wife) I've been studying this issue for decades, I can assure you that while it is absolutely critical to have properly functioning load lifters (30-45* angle), and weight on the hips, it's impossible for the shoulder straps not to contact the protruding collarbone - and there in, both figuratively and literally, is the rub. So while the two points you make are indeed important, they will absolutely not cure all (or even most) of the problem.

Having just returned from a 6 day outing into the Boundary Waters, I certainly think this would be a great option.