Best play-style for injury prevention?

[Red Sunset]

As I've posted before, I've just had my second knee op in 18months. Had meniscal cartlidge tears in each knee.
Surgeon says I have to be careful about the way I play from here on out, because I have less cartlidge in my knees than normal, as a result of the operations. I'm doing physio and all that stuff. But it's got me wondering if I should alter my game style now. I tend to be a bit of an all-courter these days, and serve and volley often in doubles. Maybe if I camped on the baseline a bit more, or went for winners early, or something like that my knees might be put under less strain. What play-style is the easisest on your body? I'm 32 years old, by the way.