Sports knee: rehabilitation guide
Last reviewed 5 August 2026 · Reviewed by Dr Matthew Broadhead, FRACS (Orth) · 26 minute read
This guide is for an ISOLATED ACL reconstruction: an ACL graft with no meniscal repair. Your operation record says which operation you had. If your meniscus was repaired at the same time, you follow a different, more protected programme: see the guide "ACL reconstruction with meniscal repair" instead. The two programmes are different, and following the wrong one matters. If you are not sure which applies to you, call the rooms before you start.
An ACL reconstruction is a long game. The graft is strong enough for daily life quickly, but turning it into a knee you can trust on a netball court or a football field takes nine months and more, not because the rehabilitation is slow, but because the biology is. Every timeframe in this guide is typical, not a rule, and Dr Broadhead’s instructions for you always override the general figures here.
The work starts before surgery. Prehabilitation: getting the knee straight, the swelling settled and the quadriceps working before the operation, is part of the programme, not a warm-up act for it. A quiet, strong knee going in predicts a better knee coming out. If you are reading this before your operation, that is your job now.
The anterior cruciate ligament (ACL) runs through the centre of the knee and stops the shin bone sliding and rotating forward under the thigh bone. A torn ACL does not heal reliably, so in a reconstruction the torn ligament is replaced with a graft: a piece of your own tendon, taken from the hamstrings, the patellar tendon (with a small block of bone at each end, called BTB), or the quadriceps tendon. Your operation record says which graft you had.
The graft is passed through tunnels drilled in the shin and thigh bones and fixed in place. The fixation is strong from day one, which is why you can put weight on the leg immediately. The graft itself then spends months remodelling into a living ligament, and for much of that time it is weaker than it feels. That gap between how the knee feels and how strong the graft is runs through everything in this guide.
At the same operation, the rest of the knee was inspected. In your case the meniscus did not need a repair, which is why this guide, and not the meniscal-repair version, applies to you.
Best practice after ACL reconstruction is criteria-based progression. Time sets the earliest possible date for each step; objective criteria decide whether you actually move. Each phase in this guide lists both. Feeling good is not a criterion: the graft cannot be felt.
The first fortnight has four jobs: full extension (a completely straight knee), minimal swelling, quadriceps activation without a lag, and normal walking. Everything downstream depends on these four. If you do nothing else in the first two weeks, do these.
Increasing swelling after a session means the load was too high. A knee that is bigger the next morning means you did too much yesterday. Use the knee’s response, not the calendar, and not enthusiasm, to set the pace.
You will notice other ACL patients in braces and wonder why you are not. Routine post-operative bracing after an isolated ACL reconstruction does not improve laxity, range of movement, pain, graft survival or function, so it is not used routinely. Braces are used where the meniscus was repaired, where other ligaments were involved, or where quadriceps control is poor. Your protection is the programme itself: criteria before progression, and time before sport.
Returning to pivoting sport before nine months substantially increases re-injury risk. Each additional month of delay up to nine months meaningfully reduces that risk, and passing a full discharge test battery reduces it further. The two together are far stronger than either alone. This is why the answer to "my knee feels great at six months" is still nine months.
Hamstring graft: avoid heavy resisted hamstring curls and end-range hamstring stretching for about 4–6 weeks; some posterior thigh ache and a numb patch below the incision are common. Patellar tendon (BTB): expect more front-of-knee and kneeling discomfort; kneecap mobilisation and graded loading of the front of the knee matter more, and kneeling tolerance is a late milestone. Quadriceps tendon: expect a slower start to quadriceps activation, be patient with early strength numbers; front-of-knee tenderness settles. Your operation record says which you had.
Weight bearing
Full weight bearing as tolerated with crutches from day one
You can put as much weight through the leg as comfort allows from the day of surgery. The graft fixation tolerates walking immediately, protected weight bearing is not needed after an isolated ACL reconstruction.
The crutches are for balance, comfort and a normal walking pattern, not to keep weight off. Most people put them down between one and two weeks after surgery. The test for losing them is quality, not the calendar: you walk without them when you can walk without a limp.
Walking with a limp on a bent knee trains a pattern you will spend weeks unlearning. Short, frequent, tidy walks beat long ragged ones.
| Stage | Typical timing | Move on when |
|---|---|---|
| Two crutches | Day 0 to about 1 week | Comfortable weight bearing; knee reaching full extension in the stance phase |
| One crutch (opposite hand) | About week 1–2 | Level walking with a near-normal pattern |
| No aid | About 1–2 weeks | Walking without a limp; swelling not increasing with walking |
| Milestone | Earliest (weeks) | Typical | Latest |
|---|---|---|---|
| Walking with crutches, full weight bearing | 0 | 0 | 1 |
| Off crutches | 1 | 2 | 3 |
| Desk work | 1 | 2 | 3 |
| Wound review | 2 | 2 | 3 |
| Stationary cycling | 4 | 4 | 6 |
| Driving (right knee: criteria met, discussed with us) | 4 | 5 | 6 |
| Clinical review with X-ray | 6 | 7 | 8 |
| Physical work | 6 | 9 | 12 |
| Three-month review | 12 | 13 | 14 |
| Running (if criteria met) | 12 | 14 | 20 |
| Six-month review | 26 | 26 | 28 |
| Change-of-direction training | 26 | 28 | 34 |
| Nine-month review and return-to-sport testing | 39 | 39 | 42 |
| Return to pivoting sport (testing passed) | 39 | 44 | 52 |
| Twelve-month review | 52 | 52 | 56 |
You move to the next phase by meeting its exit criteria, not by the calendar. The week numbers are typical, nothing more.
Full extension, minimal swelling, a working quadriceps and a normal walk: the four jobs everything else depends on.
Ready for the next phase when…
Build the bend, walk normally everywhere, and lay down the double-leg strength base the later phases stand on.
Ready for the next phase when…
Turn a settled knee into a strong one: progressive gym strength, single-leg control, and the landing mechanics that protect the graft.
Ready for the next phase when…
Progressive running volume, heavier strength work, and the first jumping and agility work: all of it pre-planned, none of it reactive yet.
Ready for the next phase when…
Cutting, pivoting and reactive agility, then non-contact and finally contact team training, building the knee you will actually play on.
Ready for the next phase when…
Full training, then match play, and the permanent habits that protect both knees from here on.
Ready for the next phase when…
Little and often beats one heroic session. Each exercise lists what you should feel, sharp pain that lingers afterwards means ease off and, if it persists, call.
Keep blood moving in the calf: your main clot-prevention exercise.
10 firm pumps, every waking hour, for the first 2 weeks
Feel: You should feel the calf muscles working. Move through the full range each time.
Switch the thigh muscle back on: swelling turns it off, and everything else depends on it.
10 holds of 5 seconds, 3–4 times daily
Feel: You should feel this in the front of the thigh. A quadriceps tendon graft makes this harder at first, persist; a slow start here is expected, not a problem.
Harder: Your physiotherapist may add muscle stimulation (NMES) over the quadriceps if activation is slow.
Restore the bend, gently and often.
10 slow slides, 3–4 times daily
Feel: A firm stretching feeling is right; sharp lingering pain means ease off. A towel or plastic bag under the heel makes it slide easier.
Easier: Loop a towel around the ankle and assist the slide with your arms.
Quadriceps strength with the knee locked straight. The milestone is lifting without a lag.
10 lifts, hold 3 seconds, 3 times daily
Feel: If the knee sags as you lift (a “lag”), keep working the static quads. The lag going is the sign of progress.
Full straightening: the highest-priority exercise in this entire guide.
5–10 minutes, 2–3 times daily
Feel: A firm stretch behind the knee is exactly right. Never put a pillow under the knee to “rest” it afterwards.
Gravity-assisted full extension: the partner exercise to the heel prop.
3–5 minutes, 2–3 times daily
Feel: A firm stretch behind the knee is the goal. If you had a hamstring graft and feel a pull in the back of the thigh rather than the knee, shorten the time and build up.
Harder: A light ankle weight increases the stretch.
Keep the kneecap gliding freely so the bend and the scar do not tether: extra important after a patellar tendon (BTB) graft.
1–2 minutes in each direction, twice daily, once the dressing allows
Feel: It should feel odd, not painful.
A normal walking pattern from day one: heel down, knee straight at foot-strike, no limp.
Short walks every waking hour for the first 2 weeks
Feel: Slow and tidy beats fast and ragged. You are practising the walk you will keep: make it a good one.
Real-world double-leg strength: the base the single-leg work is built on.
2–3 sets of 8–10, once or twice daily
Feel: Share the load evenly, no swinging, and no cheating onto the good leg.
Harder: Lower the chair height, then move more weight onto the operated leg.
Thigh and hip strength through a small, safe range.
2–3 sets of 10 to about 45 degrees, once or twice daily
Feel: Knees track over the toes, no diving inward. That habit matters more after an ACL reconstruction than after any other knee operation.
Calf strength for a normal push-off when walking and, later, running.
2–3 sets of 10, once or twice daily
Feel: Even weight through both feet.
Harder: Progress to single-leg raises on the operated side.
Strengthen the last few degrees of straightening. The range the quadriceps loses first and needs most.
2–3 sets of 10, hold 3 seconds, once or twice daily
Feel: All the movement happens below the knee. Push through to completely straight every repetition, nearly straight does not count.
Range, circulation and endurance with almost no strain on the graft.
10–20 minutes, most days, from about 4 weeks once the bend allows a full revolution
Feel: Mild stretch at the top of the pedal stroke is useful; lower the saddle gradually as the bend improves.
The knee’s position sense (proprioception). The reflexes that protect the graft when the ground surprises you.
Build to 3 holds of 30 seconds each leg, daily
Feel: Quiet foot, soft knee, tall posture.
Harder: Add ball catches or small knee bends while balancing.
Soften and desensitise the scars, including the graft donor site: once fully healed.
2–3 minutes, twice daily, from about 3 weeks once healed and dry
Feel: Firm enough to blanch the skin slightly; it should not be painful. A numb patch near the incision is common: massage the edges of it; it usually shrinks with time.
Single-leg strength for stairs, slopes and: eventually: running.
2–3 sets of 8 each leg, once daily
Feel: Push through the whole foot; keep the knee tracking over the toes, not diving inward.
Harder: Raise the step height, then reduce hand support, then add load.
The controlled lowering strength that landing, decelerating and cutting are built on.
2–3 sets of 8 each leg, alternate days
Feel: Slow and controlled beats deep; keep the pelvis level and the knee over the toes.
Harder: Raise the step, slow the lowering, remove hand support.
Rebuild hamstring strength: the muscle group that actively protects the ACL graft.
2–3 sets of 10, once daily, from 6 weeks
Feel: If you had a hamstring graft, this is deliberately delayed until about 6 weeks. Some donor-site ache when you start is normal and settles.
Harder: Add an ankle weight, then progress to gym-based hamstring work with your physiotherapist.
The measuring stick for return to sport: performed and scored with your physiotherapist, not alone.
Testing sessions with your physiotherapist from Phase 4 onward, not a daily exercise
Feel: The target is at least 90% of the other leg on every test. How you land is scored as well as how far you hop. A long, ugly hop does not pass.
Sleep in whatever position is comfortable. There are no positional restrictions after an isolated ACL reconstruction.
Never sleep with a pillow under the knee. If you want support, place a pillow under the whole lower leg from calf to heel, so the knee rests straight.
For the first week or two, many people sleep better on their back with the leg elevated on pillows. It helps the morning swelling.
Expect real pain for the first week or two, needing regular pain relief: take it as prescribed and ahead of exercise sessions rather than chasing pain afterwards.
Wean the strongest medications first as things settle; most people are down to simple pain relief within a couple of weeks.
Donor-site pain is its own story: hamstring grafts commonly ache in the back of the thigh for some weeks, patellar tendon (BTB) grafts at the front of the knee, especially with kneeling, and quadriceps tendon grafts above the kneecap. All of it settles; none of it means something is wrong with the graft.
Aches, clicking, warmth and the odd twinge continue for months and are normal. Pain that is increasing week on week is not, call the rooms.
You may drive when all of the following are true:
What the research actually measures is braking reaction time on a simulator. Those studies show braking performance returns to its pre-operative level at about 2 weeks after a right hip replacement and about 4 weeks after a right knee replacement, with movement time back to normal by 6 weeks. After knee arthroscopy the simulator evidence is more conservative than common practice: in the one study that measured it directly, braking was still slower one week after surgery than before it, and had recovered by four weeks, and a 2021 review of eight studies put the average return at about six weeks. Most people having a simple arthroscopy are driving well before that, which is why the criteria above matter more than the date. But these are averages, in one study, about one in three right-hip patients still could not meet an emergency-stop benchmark at six weeks. Treat the timeframes in this guide as targets for discussion with us, not as permissions.
No published study has compared automatic and manual cars. The logical point is simply that a manual needs the left leg for the clutch, so left-sided surgery is the relevant caution in a manual. Advice about driving earlier with a left-leg operation in an automatic is clinical judgement, not trial evidence.
In Australia, your treating doctor’s advice governs: under the Austroads "Assessing Fitness to Drive" standards, temporary post-operative impairment is a matter of clinical judgement, and commercial drivers are held to a higher standard. Driving while impaired may invalidate your insurance, check your insurer’s position. Do not drive for at least 24 hours after any general anaesthetic or sedation.
| Activity | Typical | When it’s right | Notes |
|---|---|---|---|
| Walking for exercise | From the outset | No limp; swelling stable | Short and frequent at first; build distance gradually |
| Desk work | 1–2 weeks | Comfortable sitting; able to elevate the leg; travel sorted | Get up and move hourly |
| Swimming (straight-line, no breaststroke kick early) | From wound healing, about 2–3 weeks | Wound fully healed and reviewed | Flutter kick first; breaststroke kick waits until the knee is strong and settled |
| Stationary cycling | About 4 weeks | Enough bend for a full revolution | Saddle high at first |
| Driving | 4–6 weeks (right knee); often earlier for a left knee in an automatic | All the driving criteria below, discussed with us | The left-knee-in-an-automatic advice is clinical judgement, not trial evidence |
| Physical work | 6–12 weeks | Strength and endurance for the actual duties | Modified duties in between where available: raise it at the 2-week review |
| Running (straight line) | From about 3 months: if criteria are met | Pain ≤2/10, no effusion, full range, quadriceps symmetry ≥70–80%, good single-leg squat, pain-free hopping | The criteria open the gate, not the date |
| Gym strength and pre-planned agility | Months 3–6 | Progressing under physiotherapist guidance | Bilateral then unilateral plyometrics |
| Change of direction and sport-specific training | Months 6–9 | Strength and hop symmetry approaching 90% | Pre-planned first, reactive later; non-contact before contact |
| Pivoting sport (netball, football, soccer, basketball, skiing) | Not before 9 months | Full return-to-sport test battery passed: strength ≥90%, hop battery ≥90%, movement quality under fatigue, psychological readiness | Time plus testing together protect the graft far better than either alone |
| Kneeling | When comfortable: later after a BTB graft | Wound healed; tolerance built gradually on padding | Kneeling discomfort after a patellar tendon graft is common and improves; it is a late milestone, not a danger sign |
You will often hear "no flying for six weeks" after joint replacement. Be aware that this is a convention, not a proven rule: a 2025 review found limited data and no demonstrated difference in clot risk between people who did and did not fly after hip or knee replacement: mostly within the first week.
The six-week convention reflects practical realities rather than trial evidence: managing airports and cramped seating, being past the highest-risk clot window while still on prevention, the higher baseline clot risk of long-haul flights over four hours, and individual airline and travel-insurance rules, check both, as some airlines impose their own restrictions.
If you need to travel long-haul in the first six weeks, talk to the rooms first so clot prevention, an aisle seat, stockings and on-board movement can be planned.
None of these should be watched overnight to see how they go. Early treatment of a problem is simple; late treatment is not.
EMERGENCY: 000Emergency department / call 000
GP TODAYSee your GP today
CALL THE ROOMSCall the rooms: same day
For joint replacement patients, a wound problem is never something to "wait and see". Early treatment of an infected joint replacement is vastly more successful than late treatment, call the rooms the same day.
This guide is for an isolated ACL reconstruction, no meniscal repair. Your operation record says which operation you had. If your meniscus was repaired at the same time, you follow the guide "ACL reconstruction with meniscal repair" instead: it uses a brace, restricted bending and a slower return to running and sport. The two programmes are genuinely different. If you are unsure which applies, call the rooms before starting.
Not for an isolated ACL reconstruction. Routine bracing does not improve laxity, range of movement, pain, graft survival or function, so it is not used routinely. Braces are reserved for particular situations: a meniscal repair done at the same time, other ligaments involved, or poor quadriceps control. If you see other ACL patients in braces, that is usually why. Your protection is the programme: criteria before progression, and time before sport.
Yes: full weight as tolerated from day one, with crutches for balance and comfort. The graft fixation tolerates walking immediately. Most people are off crutches within one to two weeks. The test for losing them is walking without a limp, not a date on the calendar. A limp trains a bad pattern you then have to unlearn.
Typically 4–6 weeks for a right knee, and often earlier for a left knee in an automatic. The date matters less than the criteria: off strong painkillers, comfortable in the seat, and able to perform an emergency stop at full force without hesitation: practised in a stationary car first. Confirm your own timing with us at review; your insurer’s position is worth checking too.
Desk work typically at 1–2 weeks, once you are comfortable sitting and can get there safely: set the leg up elevated under the desk and move hourly. Physical work typically takes 6–12 weeks depending on the duties, sometimes with modified duties in between. Raise your job’s actual demands at the two-week review so a plan is in place early.
From about three months, but only if the criteria are met, and they are the real gate: pain no more than 2 out of 10, no fluid in the knee, full range of movement, quadriceps strength at least 70–80% of the other leg, a good single-leg squat, and pain-free double- then single-leg hopping. Some people meet those at three months; many need longer. The date does not open the gate.
Not before nine months, and only after passing formal return-to-sport testing, for some people it is closer to twelve. Returning to pivoting sport earlier substantially increases the risk of re-injuring the graft, and each extra month up to nine meaningfully lowers that risk. Netball, football, soccer and basketball are exactly the pivoting sports the rule exists for. Time plus testing together protect the graft far better than either alone.
Because the graft cannot be felt. At six months it is still remodelling and is weaker than your knee feels. Returning to pivoting sport before nine months substantially increases re-injury risk, and each additional month of delay up to nine months reduces it. A knee that feels great at six months is the plan working. It is not evidence the plan can be skipped.
A formal test battery before you are cleared: quadriceps and hamstring strength at least 90% of the other leg (nearer 100% for high-demand pivoting sport); a hop battery: single, triple, crossover and timed 6-metre hops, at 90% or better; movement quality on drop-jump and single-leg squat, ideally tested under fatigue; and the ACL-RSI questionnaire for psychological readiness. Passing reduces re-injury risk but does not eliminate it, which is why time and ongoing prevention still apply.
Honest numbers: among athletes under 25 who return to sport, roughly one in four sustains a further ACL injury, to either knee, and the other knee is at least as vulnerable as the reconstructed one. In patients operated under 20, graft rupture alone reached 18% by five years, and almost half of those ruptures happened in the first year. Those numbers are exactly why this guide insists on nine to twelve months, full testing, and a permanent change to how you warm up.
Structured neuromuscular warm-up programmes roughly halve the risk of ACL injury, with the largest effect in female athletes. Ready-made versions exist for the sports that matter here: Prep-to-Play for AFL and AFLW, the Netball Australia KNEE Program, and FIFA 11+ for football. The dose is simple: twenty minutes, three times a week, forever. It is the single cheapest insurance policy in sports medicine.
Your operation record says: hamstring, patellar tendon (BTB) or quadriceps tendon, and it changes the details, not the plan. Hamstring: no heavy hamstring curls or end-range hamstring stretching for about 4–6 weeks; posterior thigh ache and a numb patch below the incision are common. BTB: more front-of-knee and kneeling discomfort; kneeling tolerance is a late milestone. Quadriceps tendon: a slower start to quadriceps activation, be patient with early strength numbers.
If you had a hamstring graft, yes. The tendon was taken from there, and the donor site commonly aches for some weeks, especially with stretching or resisted bending of the knee. That is why hamstring stretching and heavy curls are held back for about 4–6 weeks. A numb patch of skin below the incision is also common and usually shrinks with time. Neither means anything is wrong with the graft.
| Claim | Source |
|---|---|
| Return to pivoting sport before 9 months increases re-injury; each month of delay up to 9 months reduces it, and passing discharge criteria reduces it further | Grindem et al., Br J Sports Med 2016, Delaware-Oslo cohort (PMID 27162233) |
| Roughly 1 in 4 athletes under 25 who return to sport sustain a further ACL injury to either knee | Wiggins et al., Am J Sports Med 2016, systematic review and meta-analysis (PMID 26772611) |
| In patients reconstructed under 20, graft rupture alone was 18% at a mean 5 years, highest at 28.3% in males under 18; 47% of ruptures occurred in the first postoperative year | Webster & Feller, Am J Sports Med 2016 (PMID 27390346) |
| The other knee is at least as vulnerable as the graft: contralateral injury 8% against ipsilateral 7% | Wiggins et al., Am J Sports Med 2016, systematic review and meta-analysis (PMID 26772611) |
| Routine post-operative bracing after isolated ACL reconstruction does not improve laxity, range, pain or function | Wright & Fetzer, Clin Orthop Relat Res 2007, systematic review of bracing after ACL reconstruction (PMID 17279043) |
| Rehabilitation evidence supports early weight bearing, early extension and no routine brace or CPM after ACL reconstruction | Kruse, Gray & Wright, J Bone Joint Surg Am 2012, systematic review of rehabilitation after ACL reconstruction (PMID 23032584) |
| Criteria-based (not purely time-based) progression is best practice after ACL reconstruction | van Melick et al., Br J Sports Med 2016, evidence-based clinical practice update (PMID 27539507) |
| Athletes not meeting discharge criteria before return had about four times the graft rupture rate | Kyritsis et al., Br J Sports Med 2016, discharge criteria and graft rupture risk (PMID 27215935) |
| Hop-test battery (single, triple, crossover, timed 6-metre) with ≥90% limb symmetry as a return-to-sport criterion | Noyes, Barber & Mangine, Am J Sports Med 1991, hop-test origin (PMID 1962720), applied in the Grindem 2016 test battery (PMID 27162233) |
| ACL-RSI scale measures psychological readiness to return to sport | Webster, Feller & Lambros, Phys Ther Sport 2008, ACL-RSI development and preliminary validation (PMID 19083699) |
| Fear of re-injury is the most common reason athletes do not return to their sport; only about two-thirds return to pre-injury level | Ardern et al., Br J Sports Med 2014, meta-analysis of return to sport after ACL reconstruction (PMID 25157180) |
| Structured neuromuscular warm-up programmes roughly halve ACL injury risk, with the largest effect in female athletes | Webster & Hewett, J Orthop Res 2018, meta-analysis of meta-analyses of ACL injury-reduction programmes (PMID 29737024) |
| FIFA 11+ structured warm-up reduces lower-limb injuries in football | Thorborg et al., Br J Sports Med 2017, FIFA 11 and 11+ systematic review and meta-analysis (PMID 28087568) |
| Pre-operative rehabilitation (extension, swelling control, quadriceps activation) predicts better post-operative outcomes | Failla et al., Am J Sports Med 2016, Delaware-Oslo versus MOON preoperative rehabilitation comparison (PMID 27416993) |
| Braking performance after right-knee ACL reconstruction returns around 4–6 weeks | Brake response time after right ACL reconstruction, Arthroscopy 2000 (PMID 10705325) |
This guide is general information for patients of Dr Matthew Broadhead (Harbour Orthopaedics & Sports Medicine) and is not a substitute for the specific advice given to you by Dr Broadhead, your physiotherapist or your hospital team.
Surgical findings vary, and your protocol may differ from what is written here: your operation record and your surgeon’s instructions always take precedence.
If in doubt, call the rooms on (02) 9052 1883. In an emergency, call 000.
Last reviewed: 2026-08-05 by Dr Matthew Broadhead, FRACS (Orth).
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