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Complete patient guide
ACL rupture + reconstruction
The pop, the swelling, the knee that no longer trusts itself. Who actually needs a reconstruction, what the operation involves, and the honest road back to sport.
Does every ACL tear need surgery?
Dr Cooper's video answer is being filmed and will appear here. Short version: no, and the guide below explains who does and does not benefit.
What the ACL does, and what happens when it tears
The anterior cruciate ligament is the knee's pivot control. It stops the tibia sliding and rotating out from under the femur when you cut, land and change direction. It usually tears in a non-contact twist: a sidestep, an awkward landing, a ski catching an edge. Most people feel or hear a pop, the knee swells within hours, and pivoting sport is instantly out of the question.
An ACL rupture is not an emergency, and the first decision is not "book surgery". It is: settle the knee, understand the full injury (meniscus and cartilage matter as much as the ligament), and then choose the path that fits your knee and your life.
Do I need a reconstruction?
Who usually benefits from surgery?
People who want to return to pivoting sports (football codes, netball, basketball, skiing), people with repairable meniscus injuries, and people whose knee gives way in daily life despite good rehabilitation.
Who can do well without it?
People happy with straight-line activities (running, cycling, swimming, gym), with a stable-feeling knee after a structured rehabilitation program. This is a genuine pathway, not a consolation prize, and some people later choose surgery if instability appears.
Investigations
X-rays exclude fracture; MRI confirms the ACL tear and, importantly, maps the meniscus and cartilage. Bring your scans and reports; the meniscus findings often shape the plan more than the ligament itself.
Before any operation: prehabilitation
Whether or not you choose reconstruction, the first weeks look the same: settle swelling, regain full straightening, wake the quadriceps up. A knee that goes into surgery moving well comes out of surgery moving well. Rushing a swollen, stiff knee to theatre trades a short wait now for a stiffer knee later.
The operation
ACL reconstruction replaces the torn ligament with a graft, most commonly your own hamstring, patellar or quadriceps tendon. It is keyhole (arthroscopic) day surgery or an overnight stay, taking around 60 to 90 minutes. Meniscus tears are repaired or treated at the same time.
Graft choice involves genuine trade-offs in re-rupture risk, kneeling comfort and hamstring strength, and it should fit your sport, your age and your goals. I will walk you through the options and give you a clear recommendation rather than a menu. My fellowship training in arthroscopic ligament reconstruction shapes both the operation and the rehabilitation that follows.
Honest risks
- Graft re-rupture: overall around 1 in 20, but meaningfully higher in athletes under 20 returning to pivoting sport. Completing rehabilitation and passing return-to-sport testing measurably lowers the risk.
- Injuring the other knee: roughly as likely as re-tearing the graft; the strength and landing work protects both sides.
- Infection: uncommon, well under 1 in 100 for arthroscopic surgery.
- Stiffness or loss of extension: minimised by proper prehabilitation and early straightening work.
- Numb patch near the scars: common, small, and rarely troublesome.
- Blood clots: uncommon in this group but screened for and prevented.
- Long-term arthritis risk: an ACL injury raises the knee's long-term arthritis risk whether or not it is reconstructed; protecting the meniscus is one of the strongest arguments for good treatment, surgical or not.
The road back, month by month
| Timeframe | What to expect |
|---|---|
| Week 0 to 2 | Crutches for comfort, full weight-bearing for most. The jobs: swelling down, knee straight, quadriceps switched on. |
| Week 2 to 6 | Walking normally, stationary bike, early strength work. Desk work usually from week 1 to 2; driving once you are safe, typically week 2 to 6 depending on the side. |
| Month 2 to 3 | Gym-based strengthening builds. Straight-line jogging usually begins around the 3 month mark if strength targets are met. |
| Month 4 to 6 | Running progresses; agility and landing mechanics start. This is the phase that separates good outcomes from re-injuries. |
| Month 9 to 12 | Return to pivoting sport after passing strength and hop testing, almost never before 9 months. Patience here is what protects the graft. |
Frequently asked questions
Why can't I go back to sport at 6 months?
The graft is still maturing and the numbers are blunt: returning before 9 months substantially raises re-rupture risk, especially in young athletes. The extra months of strength and landing work are the cheapest insurance you will ever buy.
▶ Video answer comingWhich graft is best?
There is no single best graft, only the best graft for you. Hamstring, patellar tendon and quadriceps tendon each trade strengths: re-rupture rates, kneeling comfort, donor-site symptoms. Your sport, age and body shape the recommendation, and I will make one clearly.
▶ Video answer comingI tore my ACL years ago. Is it too late?
No. Reconstruction can be worthwhile at any point if instability is limiting you. The assessment focuses on what the meniscus and cartilage look like now, and what you want the knee to do.
▶ Video answer comingCan my teenager's ACL be treated?
Yes. Young, growing knees need growth-plate-aware techniques and a carefully supervised return to sport, and they are also the group with the highest re-injury risk, so the rehabilitation standards are strict. Bring them in early.
▶ Video answer comingDownloads
- ACL reconstruction rehabilitation protocol (phases 1 to 5, for you and your physio)PDF coming
- Return-to-sport testing criteriaPDF coming
This guide is general information, not individual medical advice. The plan that matters is the one made for your knee in consultation. Content reviewed by Dr Rob Cooper. [Review date TBC]
Injured knee? Start with answers
Early assessment keeps every option open, whether or not you end up choosing surgery.