ACL recovery timeline, week by week.

weeks 0–2

Weeks 0-2 · the worst pain is the first 24 hours

Day one is the worst day. The BPTB-vs-hamstring RCT measured VAS pain at six-hour intervals: 5.2/10 at six hours post-op, 4.4 at twelve hours, 3.6 at eighteen, 3.5 at twenty-four, and 2.1 by forty-eight hours. The hamstring arm tracked almost identically. The BJMP daycase study, which followed people daily for a week, reported worst daily NRS of 4.1 on day one falling to 2.5 by day seven. So the rough shape is: very acute first day, sharp decline over the next three to four days, and a slow settle through the second week.

Modern MOON guidelines have you full weight-bearing from day one, with crutches used for balance and confidence rather than offloading. There is no brace in most contemporary protocols. The single hardest motor task in this window is achieving full passive extension — losing extension early is one of the few mistakes that causes lasting trouble, so the physiotherapist will push hard on prone-hangs and heel-prop drills from day three or four.

Quadriceps shutdown — the inability to fire the quad through a straight-leg raise — is the other dominant story of week one. Most people get the SLR back by day five to ten, and it is a precondition for almost everything that follows.

• wk 0 ·Full weight-bearing as tolerated (Day 0 to 2 weeks, usually with crutches)

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.

• wk 3 ·Off crutches / normal gait (2-6 weeks; criteria include quad control and full extension)

weeks 6–12

Weeks 6-12 · strength phase

Open-chain quadriceps work starts at six weeks per the MOON guideline — the historical concern about graft strain has been largely retired by recent evidence. This is where measurable strength returns. By twelve weeks most BPTB and quadriceps grafts are running on a pool or unweighted treadmill; the University of Virginia protocol uses week 7-8 for pool running and reserves full-weight-bearing running for week 12 (BPTB) or week 16 (hamstring).

Return-to-work clusters in this phase. Ozbek's systematic review of 1,791 patients reported 82.7% back to work by 75 days and 90.2% by 90 days. The graft split is real: quadriceps autograft averaged 46 days, allograft 70 days, LARS 49 days, hamstring 84 days. So plan around 7 to 11 weeks depending on graft and job type.

Pain in this window is interpolated and typically reported as 0.5-1.5/10. If the knee is still swelling visibly after activity at week 12, that is worth raising — persistent post-activity effusion is a well-recognized red flag for graft or meniscus issues and is not a normal feature of the strength phase.

• wk 8 ·Pool or unweighted treadmill running (7-8 weeks)
• wk 11 ·Return to work (About 46-84 days depending on graft and job demands)

weeks 12–26

Weeks 12-26 · running and progressive load

Running on dry land starts here. BPTB protocols typically open at week 12 and hamstring protocols at week 16, gated on quadriceps and hamstring strength at least 80% of the other leg. Most people find the first few sessions humbling — the knee tolerates the load, but the cardiovascular and neuromuscular system is rebuilding from scratch.

By six months KOOS-Pain is typically in the 80-85/100 range, which translates to roughly 1-1.5/10 on an NRS — the conversion is approximate, since KOOS-Pain is a multi-item questionnaire and NRS is a single number. The shape of recovery is mostly complete by this point; the remaining work is strength symmetry, neuromuscular control, and psychological readiness.

Plyometrics start around month four to five in most protocols, beginning with bilateral landings and progressing to single-leg work by month six. The first cuts and changes of direction usually happen toward the end of this phase, under controlled conditions.

weeks 26–52

Weeks 26-52 · return to sport

Return to pivoting sport is gated on the AOSSM 2025 criteria: minimum nine months, quad and hop strength both at least 90% of the other side, and an ACL-RSI psychological readiness score of at least 80%. The Lai meta-analysis of elite athletes reported a pooled return-to-pre-injury-level rate of 83%, with the time-to-return clustering between six and thirteen months depending on sport. Soccer players take a pooled mean of about 258 days. The pool of evidence is uniformly clear that returning before nine months substantially increases reinjury risk, especially in athletes under 20.

At twelve months the Swedish National Knee Ligament Register reports KOOS-Pain of 85/100 and KOOS Sport/Rec of 65/100 — so the joint is essentially pain-free but sport-specific function lags. The MOON 10-year follow-up shows KOOS-Pain holds at 94/100 long-term in the median patient. If pain at twelve months is materially worse than this — say below 70 on KOOS-Pain, or above 3/10 on NRS — that warrants imaging and a conversation about graft or meniscus integrity.

• wk 39 ·Return to sport / pivoting clearance (9-12 months, criteria-based)