Richard's splint alternative post knee surgery

Currently our orthopaedic surgeons put a Richard's splint on in theatre post knee surgery such as ACL's, for temporary immobilisation until the physio's can fit a hinged knee brace in recovery.  The Richard's splints are often only in place for 1-2 hours, then binned.  We wanted to look at surgeons putting the hinged knee brace on in theatres just locked in extension, but they have advised it takes longer and will delay the theatre list.  They have advised it is unsafe to leave the knee without immobilisation whilst patients are recovering from anaesthesia.  What do other people use in this situation?