week 4 · last reviewed 2026-06-05
ACL recovery: week 4
Clinical procedure: ACL reconstruction.
Typical, evidence-anchored estimate only. It is not medical advice, not a prediction for your body, and not a substitute for your surgeon or clinician.
what's typical at week 4
typical pain · week 4
Around week 4, the typical pain band sits at 2/10 (range 1–3). This is a soft, interpolated read: this exact week wasn't measured, so the band is bridged between the nearest measured points. Treat it as a rough guide, not a target to hit.
weeks 2–6
Weeks 2-6 · off crutches, normalizing gait
Off crutches happens around week 3 in modern protocols, gated on quad control, no straight-leg-raise lag, and full extension — not on a calendar date. The University of Virginia protocol allows hamstring/allograft patients to take partial weight-bearing through week 6 if the surgeon prefers, but BPTB patients are typically off crutches earlier. Pain in this window is interpolated rather than measured, but is consistently in the 1-3/10 range — most people report that the joint feels stiff and weak rather than painful.
Brace use, where any brace was used at all, ends in this window. Modern MOON guidelines do not recommend a brace post-operatively at all; older protocols and some surgeon preferences keep one through week six.
Swelling is the dominant constraint at this stage. The classic mistake is doing too much in the second and third weeks, finding the knee swells, and losing two weeks to a re-irritated joint. Cryotherapy, elevation, and rest still earn their keep here.
documented at this week
This week
Crutches go when the quad wakes up
Crutches are weaned as tolerated, usually somewhere in weeks 2-6. The gates protocols actually watch are quad control and full knee extension, not the date.
Where it shows up
Loading the knee early is linked to less kneecap pain
The MOON guideline notes that in the one study of immediate full weight bearing, front-of-knee (patellofemoral) pain fell from 35% to 8%. The front of the knee is the spot most affected, and early loading is linked to less of it.
Where it shows up
Where it hurts after a patellar-tendon graft, and how often
After ACL reconstruction with a bone-patellar tendon-bone graft, the front of the knee is a documented site of lingering soreness. Across Level I trials, anterior knee pain was reported by anywhere from 5.4% to 48.4% of people, and pain specifically with kneeling by 4.0% to 75.6%. The wide ranges reflect how differently studies measured it, not a single fixed number.
The bigger picture
Patellar-tendon vs hamstring graft and the chance of a second surgery
Across 45,998 ACL reconstructions in the Scandinavian registries, the risk of needing a revision was lower with patellar-tendon grafts than with hamstring grafts (hazard rate ratio 0.63). The same direction held across age, sex, and cartilage-injury subgroups. Which graft you have is decided in the operating room, so this is a difference between recovery paths rather than something a person changes after surgery.
Coming up
Needing a procedure to free up a stiff knee is uncommon
In an insurance-database review of 7,798 people who had ACL reconstruction between 2007 and 2017, 115 of them — about 1.5% — went on to need a manipulation under anesthesia within the first year to address stiffness. The other 98.5% did not.
Coming up
Graft choice shifts how soon braking ability returns
In a driving-simulator series of 27 people after right-knee ACL reconstruction, those with a tibialis anterior allograft were back to normal braking by 3 weeks, hamstring autograft by 6 weeks, while the bone-patellar tendon-bone autograft group still showed braking limitations at 6 weeks.
Coming up
Driving brake reaction tends to normalize around 4 to 6 weeks for a right knee
Across the pooled studies, brake reaction time returned to control-level values at roughly 4 to 6 weeks after a right-sided ACL reconstruction and roughly 2 to 3 weeks after a left-sided one. For people driving a manual transmission, the reviewers noted laterality did not matter and the 4-to-6-week window applied either way.
Back to work
Back at work: 90% within 90 days
Across 13 studies (1,791 patients), 90.2% were back at work within 90 days. Average time varied by graft — about 46 days with quadriceps tendon, up to 84 with hamstring.
Back to work
Almost everyone gets back to some form of work
Across 13 studies and 1,791 patients, 99.1% eventually returned to work — about 1,781 of 1,791. The variation is in how long it takes, not whether it happens.
milestones around now
- wk 3 ·Off crutches / normal gait (2-6 weeks; criteria include quad control and full extension)
- wk 8 ·Pool or unweighted treadmill running (7-8 weeks)
sources
What this page is built from
- MOON longitudinal prospective ACL reconstruction cohort prospective cohort · reliability 10/10
- MOON ACL reconstruction rehabilitation guidelines society guideline · reliability 9/10
- Immediate post-operative pain in ACL reconstruction RCT · reliability 7/10
Track your own week-by-week so a flare doesn't erase the months behind it.
Start a recovery logThis is a typical, evidence-anchored reading of acl recovery at week 4 — not medical advice, not a prediction for your body, and not a substitute for your surgeon or clinician.