Knee
The knee gets very little stability from its bones, so it relies on ligaments and muscles to hold it together. That makes it one of the most commonly and seriously injured joints in football. Most serious knee injuries happen without contact, and many of them can be prevented.
Three things every coach should know
1. A knee that swells within an hour is always serious. Rapid swelling means bleeding inside the joint. The player needs medical assessment the same day.
2. Many serious knee injuries are preventable. A structured warm-up such as the FIFA 11+ or the Power Up To Play PEP programme can reduce serious knee injuries by up to half.
3. Strong thigh muscles protect the knee. The quadriceps are the knee's most important stabilisers, and every rehabilitation and prevention programme centres on them.
- The knee swells quickly, within about an hour of the injury
- The player felt or heard a “pop” or “snap”, especially when twisting, landing or changing direction
- They cannot put weight on the leg, or are very reluctant to
- The knee gave way or feels unstable
- The knee is locked and will not straighten fully. Do not try to force it straight
- After a direct blow to the kneecap, they cannot straighten the knee and walk within 10 minutes
Rapid swelling or suspected fracture: go to A&E or an urgent treatment centre. You cannot diagnose these injuries on the touchline and you are not expected to. Recognising the pattern is enough.
On the touchline
Take the player off
Do not let them try to play on. A twist with a pop and swelling is treated as a serious ligament injury until a professional says otherwise.
Compress and elevate
Apply an elasticated bandage and raise the leg. Ice can be used briefly for pain relief: 10 to 15 minutes, wrapped in a cloth, never directly on the skin.
Get the right help
Any red flag above means same-day assessment. If a fracture is possible, give the player nothing to eat or drink in case they need treatment urgently.
Pain relief and handover
Paracetamol for pain. Avoid ibuprofen for the first 48 hours. Tell the parent or carer what happened and what to watch for, and write down how the injury happened.
Common knee problems
How soon should a professional see the player? Each problem below is tagged:
- Same dayGet medical advice today: A&E, urgent treatment centre, GP or NHS 111
- Within a few daysBook a GP or physiotherapist
- Coach-supportedManage at the club, refer if not improving
ACL tear Same day
The anterior cruciate ligament sits deep inside the knee and controls the shin bone sliding forward and twisting. Most tears happen without contact: a sudden change of direction, slowing down sharply, or landing with the knee falling inwards.
- Pop or snap, rapid swelling within 30 to 60 minutes, knee feels unstable
- An MRI scan is usually needed to confirm it
- Most active footballers are advised to have reconstruction. Recovery typically takes 9 to 12 months
MCL sprain Within a few days
The medial collateral ligament runs down the inner side of the knee and is usually hurt when the knee is pushed inwards, often in a tackle. It has a good blood supply and heals well, almost always without surgery.
- Pain and swelling along the inner knee, usually able to walk
- Pain on the inside and deep in the knee, or rapid swelling, suggests an ACL injury too: same-day assessment
Meniscus tear Within a few days
The menisci are two C-shaped cartilages that help the bones fit together and spread load. They can tear when the knee twists while bearing weight. Swelling builds over hours rather than minutes.
- Pain on the joint line, clicking, catching or giving way
- A locked knee needs urgent assessment. Do not force it straight
- Care has changed: surgeons now repair or preserve the meniscus wherever possible rather than removing it
Kneecap pain (patellofemoral pain) Coach-supported
A broad ache around or behind the kneecap that comes on gradually, worse on stairs, squatting, kneeling or sitting with the knee bent. Very common in teenagers and young adults.
- Not dangerous, but can be persistent
- Managed with strengthening of the thigh and hip muscles, not rest. Players can usually keep training with some changes
- See a physiotherapist if it is not improving within 2 to 3 weeks
Osgood-Schlatter's Coach-supported
Irritation where the tendon below the kneecap pulls on the growing shin bone, causing a tender bony lump just below the knee. Common in active children aged 10 to 15, especially during growth spurts. A similar condition at the bottom of the kneecap (Sinding-Larsen-Johansson) is managed the same way.
- Settles when growth stops, usually by 15 or 16
- Manage the load rather than stopping football: reduce intensity when sore, ice after activity, stretch the thigh muscles
Recovery and return to play
Mild MCL sprain
Early movement within comfort and progressive strengthening.
Moderate MCL sprain
A hinged brace may be used for a few weeks to protect the ligament, on professional advice.
Severe MCL sprain
Guided by a physiotherapist or doctor.
ACL reconstruction
Rehabilitation in stages: movement, then strength, then balance, then football-specific work, then a structured return to matches. Waiting times can make this longer.
Return should be based on what the player can do, not on a date. Before returning, they should be able to walk, jog, run, change direction and land from a jump without pain or the knee feeling unstable. For anything more than a minor knee injury, a physiotherapist will help them get back sooner and more safely.
Prevention: the most important part
Use a structured warm-up
The FIFA 11+ or the Power Up To Play PEP programme takes 10 to 20 minutes and replaces your usual warm-up rather than adding to it. Use it before training and matches, at least 2 to 3 times a week. Teams that use these warm-ups also tend to perform better.
- Coach technique, not just completion. Watch for knees falling inwards in squats, lunges and landings. Coach “knees over toes”.
- Prioritise girls' and women's teams. Female players are about two to three times more likely to injure their ACL than male players, and prevention programmes work especially well for them.
- Knee braces do not prevent injury in players who are not injured. Strength, balance and good movement do.