Sorry to hear about your knee. As with most everything, TIME will tell. If an injury isn't rushed and allowed to follow the natural course of healing and the like. A long time is relevent, and in that, to rush it will mean that you'll never be able to progress positively. Rank can wait because it's just not that important. Knowledge and the like will progress if you're proactive about it!! Take care, take time to heal properly, and listen to your DOCTOR and not your Sensei, unless your Sensei is also your Doctor.