I would be more worried about the biomechanical implications and health consequences rather than looks. Did you talk to several doctors regarding the risk of arthritis, yet?
its just mechanical if it happens. There are two types of arthritis basically. Rheumatoid arthritis and Osteoarthritis. Rheumatoid happens due to a genetic problem. And osteoarthritis happens due to wear and tear of the joint cartilage.
This is not related to ll whatsoever. If it happens it happens and doesn't happen it doesn't happen. Regardless of if som1 has done ll or not. Although, yes with ll it can happen more often because when the bone is lengthened, if it is not exactly corrected as before (given it was in correct alignment before) probably there will be more wear and tear on one side of knee joint which will put more pressure on cartilage on that side causing compression and eventually over the years it could end up to become bone-on-bone contact which we call arthritis.
Best way to avoid it is see the bones straight and knees are perfectly dividing weight on both sides of bones, by using photographs and x-rays. simple. In my case bones are sitting aligned, nice and good.
BTW in some cases the bone was already misaligned or there was slight more weight on one side of the knee due to slight bowed leg naturally or knocked leg before ll operation, or one leg was slightly shorter which is very common, so one knee joint was contantly taking more weight, so actually during ll corrections if thats fixed it will actually remove the chances of osteoarthritis the person was destined to have. ironically