This feeling kicks in at various times and it usually is a good sign when one is asking this question - so...that's the positive news. On the not-so-positive news is the answer - NO, YOU ARE NOT DONE YET !
This first usually kicks in when one is doing the most basic exercises at therapy and wondering when the exercises are going to kick in. Surprise ! The exercises did kick
in ! One then has to learn an impprtant word - patience ! This is a real slow going challenge but the goal is to avoid setbacks and keeping moving to the next step in the recovery process.
I'm trying to make an attempt to finally finish this website. If some of this info seems to not fall exactly in-line with what was said elsewhere - it's just because of the different timeframes this was all written.
Full Flex And Extension
As discussed in another section, extension is first thing to get squared away and it is usually squared away from the start or during the first 3-4 weeks. 0 degrees is the usual goal but some OS/PT may feel better that one achieve some hyperextension equal the other leg.
Full flex - Most gains are in the first 8-12 weeks. After that time, some minute amount of improvement is possible but the big gains are over. 135 degrees was considered by my PT & OS as the minimum to be considered full flex since most activities can be done with this minimum. Max full flex is heel to butt which for some is 150+ degress of flex. (I wound up with about 145+ degrees flex which equated to heel to butt with sneakers on.)
ACL Established ?
Once again, I am not a medical professional but from what I have gathered, the ACL withers a bit after it is installed and the period from 1-2 months post-op it gets somewhat weaker but not exactly sure how much weaker. It must get fairly strong by 4-7 months because that coincides with when many get a sports release. The fact is that I have read articles that indicate that the ACL may take as long as 1 1/2-2 years to gain full functional strength. This may explain why there are some OS out there that will recommend a custom sports brace for a year after getting the sports release.
Also some reconstruction methods (Hamstring autograft and allograft) may be more prone to stretching in the later recovery period just when some are itching to make an early return to activities. It is especially important to follow the OS's recommendations for returning to activities since none of us are that knowledgeable with just what is happening inside there with the new ACL. Muscle strength is not a guide but does help to stabilize the knee and assist the ACL.
Full Muscle Strength
My own experience was that when I had a partial ACL tear and a cartilage trim (but no reconstruction and 8 years younger than when I had the reconstruction) - recovering muscle strength was easier - 3 months to full muscle strength.
BUT...throw a reconstruction into the mix, the recvery to full muscle strength takes quite some time.
Based on responses on Bob's Board, it would seem that teenagers and those in their 20s are capable of bouncing back with full muscle strength achievable in about 3 months or so. The rest of us, it can take 6-9 months.
BUT WHAT IS THE GOAL ?
Some OS may have you graduate from therapy and pronounce you well on your way to making a full recovery and never mention the goal to get back to 100% full muscle strength and maintaining it. Only thru regular exercising and a commitment to doing both dual leg and single leg resistance exercises does anyone have any hope of getting to and maintaining full muscle strength. This would be "the goal" for the serious athlete. Because competitive sports demand equal strength in both legs and this helps also avoid reinjuring the leg or injuring the good leg (from overuse).
An OS may release an individual much earlier than achieving "the goal". So..when others are undergoing a reconstruction and get released before or after your experience - remember that each OS has his own protocol and "the goal" may or may not be part of it.
I was released at 6 mos post-op at 85% full muscle strength but was to return at 7 1/2 months for a strength check - I was then at 100% full muscle strength.
When Released ?
Part of that answer is contained to the right in the Full Muscle Strength paragraph.
I would say the norm is 6 months post-op. Therapy ends earlier at say 1- 3 months post-op and then everyone generally exercises at home or at the fitness center with more aggresive resistance exercises.
The release can be influenced by many factors - Are you normally athletic and bounced back quickly in muscle strength, did your insurance coverage/carrier have an influence on releasing early and you taking it from there, did you have the absence of setbacks thru your recovery, did you have more knee deficiency complexities ?
Some get released as early as 3 months post-op and others as late as perhaps 8 months post-op. The younger ones tend to get released earlier but if released early, then they are also the group that is more apt to get prescribed a custom sports brace due to the early release. The brace is worn only during cutting type sports. Many do not get prescribed a brace for the first year after a reconstruction but it is a possibility and so that is why I mentioned it.
I was not required to wear a brace when I was released at 6 months post-op.