I used Open Evidence AI to ask the question do knee braces reduce knee injuries. The evidence does not clearly support that prophylatic knee braces reduce knee injuries in offensive lineman specifically. Overall data across multiple studies is inconsistent, and the landmark randomized trial at West Point showed benefit mostly in the defensive linemen, no change in the OL numbers. A few studies have noted an increase in injuries.
Some team physicians continue to brace linemen, but this is based on biomechanical plausibility and institutional preference rather than definitive clinical evidence.
Definitely no strong data to support prophylactic knee bracing.
I asked a follow up question on previous knee injury and the benefits of bracing. Other than the psychological benefit there is not a marked increase in prevention of another knee injury.