A grade is a short way of saying how much of a ligament or muscle is injured. It appears in clinic notes and on scan reports, and it is often read as a recovery date. It is not one. This guide covers what the grade describes, how it is decided, and what studies report about recovery for a few common injuries.
Assessing and treating knee pain in Burlington, Ontario.
When to see a doctor firstBroader Knee Pain GuideA sprain is an injury to a ligament. A strain is an injury to a muscle or its tendon. A common three-grade system describes mild damage as grade 1, a partial tear as grade 2 and a complete tear as grade 3.
| Grade | In the common three-grade system |
|---|---|
| Grade 1 | Mild fibre damage. The area may be sore or swollen, with little or no extra looseness in the joint. Pain can still limit movement or strength. |
| Grade 2 | A partial tear. A ligament injury may allow more movement in the joint, and a muscle or tendon injury may reduce strength. Bruising and swelling can occur. |
| Grade 3 | A complete tear. A ligament injury can leave the joint markedly loose. A muscle or tendon injury can reduce function a great deal, sometimes with a visible gap or a change in the shape of the muscle. |
Not every report uses this system. Some grading systems use different definitions. The British Athletics classification for muscle injuries, for example, runs from 0 to 4 and adds a letter for where in the muscle the injury sits. A grade means little until you know which system it comes from and which structure it describes.
A joint that looked dislocated, or a foot that turns cold, pale or blue after a knee injury
Go to emergency now, even if the joint has moved back into place.
Calf pain, swelling or warmth in the days after an injury
Seek same-day medical assessment to rule out a blood clot. Call 911 for sudden shortness of breath or chest pain.
Unable to take four steps on the leg after a knee or ankle injury, or marked tenderness directly over a bone
Go to urgent care or emergency to check for a fracture before starting rehab.
New difficulty lifting the foot, or numbness that does not settle, after a knee injury
Seek same-day medical assessment. A nerve may be involved.
A joint that gives way or feels markedly loose
Arrange prompt medical assessment. This can change the treatment and whether imaging is needed.
A visible gap or a change in the shape of a muscle after an injury, or a sudden major loss of strength
Arrange prompt medical assessment for a possible complete tear.
A grade can come from the exam or from a scan, and the two describe different things. A clinical grade for a ligament reflects how much the joint opens under gentle stress compared with the other side. An imaging grade describes how the tissue looks.
They do not always match. In a study of 362 people with a recent knee injury, the grade given to the MCL on examination and the grade given on MRI agreed only moderately.
In clinic I look at how the injury happened, where it is tender, how the joint moves, how strong the muscle is and how stable the joint feels. Pain and swelling can limit some tests in the first days, so I may repeat them at a later visit. The plan also depends on what else is injured and on how the area responds as rehab goes on.
Walking comfortably, returning to training and returning to competition are different stages of recovery. The grade helps describe the injury, but it does not give a return date. The figures below come from studies of particular groups of athletes, and each says what was measured.
Early on, the area is protected from the movement that injured it while the rest of the limb keeps moving. Strengthening exercises are then added and progressed as the tissue tolerates load. The last stage is the specific work for your sport or job: sprinting, cutting, jumping or lifting.
Return to sport depends on symptoms, stability, strength and sport-specific testing, alongside the time and protection the injury needs to heal.
In the common three-grade system, a grade 2 sprain describes a partial tear of the ligament. "Sprain" is the broader word. It also covers milder injuries and complete tears.
The grade describes the pattern of injury, not how much it hurts, and even a mild injury can be painful. Severe or increasing pain, or symptoms that do not follow the recovery you were told to expect, should be reassessed.
Yes, depending on the structure and on what else is injured. Many complete tears of the MCL alone are managed without surgery, and some complete tears of the PCL alone are too. A complete injury to the outer and back corner of the knee is most often treated surgically. A complete tear needs a medical assessment, but the grade alone does not decide the treatment.
Readiness is judged from movement, strength, balance and progressively harder activity. The limb should cope with the demands of training or work without giving way, and without a marked rise in symptoms during or afterwards. Confidence in the limb and the time the injury needs to heal are considered as well.
Not always. Many sprains and strains are graded and managed from the exam alone. I cannot order imaging. When imaging would change the plan, I flag it to your family doctor or a sports medicine doctor and refer you.
The main sources behind this guide. Other studies are named in the text where they are used.
2014 Pollock N, James SL, Lee JC, Chakraverty R. British Journal of Sports Medicine
States that the commonly used three-grade muscle injury systems lack diagnostic accuracy and give limited information about prognosis, and proposes a system graded 0 to 4 on MRI with a letter for where in the muscle the injury sits.
2024 Brown JS, Olsson O, Isacsson A, Englund M. Research in Sports Medicine
In 362 patients with an acute knee injury, agreement between the clinical grade and the MRI grade of the MCL was moderate (weighted kappa 0.56).
2020 Serner A, Weir A, Tol JL, et al. Orthopaedic Journal of Sports Medicine
In 81 male athletes on a supervised criteria-based program, return to full team training took a median of 18 days (interquartile range 14 to 27) for MRI grade 0 to 2 injuries, with no statistical difference between those grades, and 78 days (68 to 98) for grade 3 injuries.
2020 Serner A, Weir A, Tol JL, et al. American Journal of Sports Medicine
In the same group of athletes, the strongest predictors of a longer return were tenderness at the attachment of the adductor longus or a defect that could be felt, and the strongest MRI predictor was injury where the tendon meets the bone.
2006 Giannotti BF, Rudy T, Graziano J. Sports Medicine and Arthroscopy Review
Reports that isolated grade I and II tears of the MCL and most grade III tears can be treated without surgery with a supervised, functional rehabilitation program.
2016 Chahla J, Moatshe G, Dean CS, LaPrade RF. Archives of Bone and Joint Surgery
Reports that complete injuries to the outer and back corner of the knee rarely heal with non-operative treatment and are most often treated surgically.
2017 Agolley D, Gabr A, Benjamin-Laing H, Haddad FS. The Bone & Joint Journal
In 46 athletes with an isolated grade II or III PCL injury treated with bracing and rehabilitation, the mean time to sport-specific training was 10.6 weeks and to full competitive sport 16.4 weeks (range 10 to 40).
2021 Smith MD, Vicenzino B, Bahr R, et al. British Journal of Sports Medicine
An international expert consensus noting that no guidelines existed for return to sport after an ankle sprain, and agreeing on assessment items in five areas: pain, ankle impairments, athlete perception, sensorimotor control, and sport and functional performance.
Fuller pages for each injury, with how I assess and treat it.
I see patients for knee pain at Endorphins Health & Wellness Centre in Burlington. The clinic serves people coming in from Burlington, Waterdown, Oakville, Hamilton, Flamborough, and Carlisle, with free parking on site and a ground-floor entrance.
Burlington hours
