A 39 year old auto mechanic has a slight instability of the knee, no atrophy and a preclusion from heavy lifting. What is the level of permanent disability?

• A. 12%
• B. 19%
• C. 22%
• D. 25%

Answer: (C)

Permanent disability ratings look at how a physical impairment affects work capacity, not just the anatomical injury. A knee with slight instability shows some functional limitation, but the leg remains without atrophy, so the structural impairment isn’t extremely severe. The key factor here is the work restriction: being unable to perform heavy lifting indicates a meaningful loss of earning capacity beyond the pure joint instability. The rating system assigns a percentage that reflects this combination—slight knee instability with no atrophy plus prohibition on heavy labor yields 22 percent. If there were muscle atrophy, the rating would be higher; if the heavy-labor restriction weren’t present, the rating would be lower. So 22 percent best represents the impact on the worker’s ability to perform work given the knee condition.