This blog focuses on pain under or around the kneecap. It’s a detailed blog about all the factors that cause the is pain and need to be addressed to get rid of the knee pain. .If you prefer a quicker read, check out my quick read post on the same topic.
It can be referred to as chondromalacia patella, runners knee, and anterior knee pain. As we learn more about the mechanism of this type of pain, patellofemoral pain (PFP) is the now preferred term to describe it.
The symptoms of PFP is pain that is felt around or behind the kneecap. It can be hard to get your fingers on the pain. Generally the pain is aggravated by activities that require bending the knee such as standing up from sitting, squatting (affects 80% of people), running, walking up and down stairs, down hills, or using the clutch or accelerator. It can be sharp or dull.
There can sometimes be crepitus or grinding sensation when moving the knee, there may be slight swelling, and 71-75% of people will have pain when pressing around the edge of the kneecap.
If your knee pain is related to the outside side of the knee please check out my blog on ITB pain
Why does kneecap pain happen???
The main cause of PFP is thought to be due to misalignment of the kneecap as it moves in it’s groove over the knee. In many cases the kneecap is found to track towards the outside of the groove. The kneecap can also to be tilted towards the outside of the knee. This leads to increased joint stress either under the kneecap itself or the outside of the bony groove it travels in. Over time this can lead to degeneration of the cartilage and irritation of the bone lying under the cartilage.
The abnormal loading can also affect other structures within surrounding the kneecap such as the ligaments, fat pad and other joint tissue.
The knee joint sits between the foot and the hip. Imbalances or faulty movement patterns at the hip and/or foot can be the source of the issue as it creates a knee joint that is not correctly aligned. This is important to bear in mind as it influences the treatment for your knee.
A thigh that rotates inwards
At the hip one of the main findings is that some people with PFP have a femur (thigh bone) that rotates inwards under the kneecap. This occurs when they are weight bearing, such as running, stepping, and landing from a jump. It leads to increased stress on the kneecap cartilage at certain angles of knee flexion (15 degrees and 45 degrees). This is why your knee can hurt at certain points when bending the knee but not at others . Increased inward rotation of the femur (just 5-10°) during walking increases stress on the kneecap joint by ~30%.
In some people it is easy to spot if the thigh bone rotated inwards and less easy in others. If your kneecap points inwards rather than straight ahead it can be an indication that your have excessive rotation. If you flick your ankles out to the side while running it can also indicate increased femoral rotation. See photos.
Too much hip adduction
Weakness in the gluteal muscles and hip abductors, can cause the knee to drift over the arch of the foot when lunging or squatting. This is known as excessive hip adduction and can lead to incorrect knee alignment. Often both excessive internal rotation and adduction occur together. If your knee tends to drift over the arch of your foot when you do a squat it may indicate that you have excessive hip adduction. Women tend to exhibit greater inward drift of the knee over the foot in weight bearing activities, and may be more susceptible to this type of injury than men.
I have written another blog which outlines how to check if your gluteals and core need strengthening. It will help you check out your own knee alignment and determine if you need to take some remedial action. Check it out here
If you are a cyclist, increased hip adduction and/or internal rotation can be observed by watching whether your knee drifts inwards over the arch of your foot on the down stroke. Ideally it would stay in line with the centre of your shoe. More on this in my blog here
A tight IT band
People with PFP can have tighter and thicker iliotibial bands (ITB) when compared to those who are pain free. A tight ITB has a substantial effect on kneecap alignment as it contributes to the pull of the kneecap towards the outside of the knee. An ITB can often tighten up when the hip abductors and external rotators are weak. It the ITB itself is the source of knee pain, pain if felt towards the side of the knee on the outside of the leg rather than over or under the knee itself. There is more on ITB pain in my blog here
Impaired Quad Function
Impaired quadricep function is a common finding in people with PFP. The quads are 4 muscles located across the front of thigh – at the outside, middle and the inside. They insert into the top the kneecap. When working properly the quads fire and help to control the tracking of the kneecap in the groove. In PFP it has been found that the quads on the inside (vastus medialis) have reduced activation and/or delayed onset of timing compared to the outside quads (vastus lateralis). This may result in the vastus lateralis pulling and tilting the kneecap towards the outside of the knee. This imbalance can occur as the lateral quads work to compensate for weakness in the hip abductors (again!) and also for postural reasons such as excessive arching of the lower back, or standing with the knees locked straight (hyper extended knees) or leg length differences.
Not only can the quads be impaired, they can also be weaker in those with PFP. This weakness can exist prior to the onset of pain, and as a result of pain.
Cyclists may have very tight quads which can also put pressure on the kneecap. This can be occur due to not pedalling in a circular nature i.e. putting more force into extending the knee on the down stroke and not using the gluteals and hamstrings enough to initiate the upstroke.
Bike set up can also contribute to knee pain in cyclists particularity where the saddle is too low for the rider. With cyclists I would advise a professional check of their bike set up as it can be a big factor in knee pain. We don’t do bike set up checks here in the clinic so this a recommendation based on professional experience rather than trying to get you to part with your money.
The foot: rolling inwards, and reduced flexibility
At the foot excessive rolling inwards over the arch (pronation) will affect how the tibia (one of the shin bones) lines up at the knee and may lead to issues at the knee. The research shows that this is not consistently associated with PFP. Excessive pronation can be due weakness in the muscles of the feet, your foot structure, and again, weakness in the hip abductors. It can also influence the extent of pronation at the ankle. One metanalysis found that reduced range of motion in the ankle was a contributor to impaired knee alignment. If ankle range of motion is reduced it can lead to increased pronation. It also leads to increased forces at the knee, and prevents you being able to bend the knee as much causing the knee to drift in over the arch of the foot putting the kneecap at a high risk of injury.
Variances in hamstring strength at the inside and outside of the knee can lead to a shin bone that points outwards compared to the thigh. If you sit up on a high bench with your feet dangling in the air, note if your feet point straight ahead (expected) or if one or both points outwards. Some people will stand with their feet pointing outwards. This may be linked to the structural alignment of their hip but can also be a compensatory pattern to help stabilize and balance the body when standing, due to weakness further up the leg and into the hip and lower back region.
Other factors affecting kneecap pain: Ligament laxity and core strength
Ligament laxity has been found to be a risk factor for PFP. There is a ligament attaching the kneecap to the inside of the femur and laxity in this may allow it to track towards the outside of the knee.
A study by Cronstrom et al found that reduced trunk lateral flexion strength, as assessed by the side plank, was associated with increased drifting of the knee over the arch of the foot in a single-leg squat. In addition, increased leaning of the trunk to the weight bearing side during a single leg squat can indicate trunk stability. This pattern can occur to compensate for weak core muscles. The side-plank tests the lateral flexion strength of the trunk and also hip abductor strength. A weakness of these core muscles may lead to both increased trunk instability and increased knee abduction that together may induce an increased risk of injury at the kneecap.
How do you get rid of kneecap pain?
Across the board and patient types, the number one method proven through research to reduce kneecap pain and return to activities are exercises for the hip and knee. Outcomes were found to be better in those who strengthened both the hip and knee, versus those who just strengthened the knee. Our approach here in the clinic is to do a full assessment from the feet up to identify problem area from which the injury may have arisen and to address these.
Research shoes that othotics are shown to be sometimes helpful for some, but this would need to based on assessment of the individual’s foot. Taping can occasionally be helpful as a measure to reduce knee pain symptoms in the very short term to allow someone do their exercises or where they insist on taking part in sporting events.
Here in at Maple Physical Therapy our approach to treating clients with PFP involves:
- a full assessment to determine the root cause of your knee pain
- massage and dry needling (or not if you don’t like needles!) to help reduce the tension around the knee, hip and foot and to give some pain relief
- provide taping and insoles if necessary
- develop a comprehensive exercise plan containing exercise picture and videos which are emailed out to you
Unfortunately there is no one silver bullet that will help fix knee pain. While many clients hope a combination massage, orthotics and a knee brace will resolve their problems it usually doesn’t. Often this clients end up changing their activities to avoid knee pain, e.g, give up playing tennis. For a better outcome in the long term, muscle imbalances need to be addressed.
If you would like to talk to us about your knee pain you can contact us firstname.lastname@example.org or phone on 01-5441225
How long does kneecap pain take to go away?
This can depend. There are a number of factors that can affect your rate of recovery from knee pain. For example:
- How long the pain existed prior to seeking treatment. The longer it was there, the longer it will take to go away.
- The extent of the pain and impact on your daily life. This is very individual. Worse pain doesn’t mean that it will take longer to go away, but if it makes it hard to perform some of the exercises it can extend your recovery time.
- If you have had it before or if there is pre-existing wear and tear in the knee can extend the recovery timeline.
- Whether you do your rehab. It won’t go away unless you address the causative factors, but this is within your control.
- Whether you fall back into postures or muscle imbalances which led to the issue initially. This realistically can happen over a long duration of time but if you know what to look out for, you can re-strengthen again and help yourself.
- Barton CJ, Lack S, Hemmings S, et al. The ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’: incorporating level 1 evidence with expert clinical reasoning. British Journal of Sports Medicine 2015;49:923-934
- Cronstrom A, Creaby MW, Nae JA, Ageberg E. Gender differences in knee abduction during weight-bearing activities: A systematic review and meta-analysis. Gait and Posture 2016 46:315-328
- Constrom A, Creaby MW, Nae J, Ageeberg E. Modifiable Factors Associated with Knee Abduction During Weight-Bearing Activities: A Systematic Review and Meta-Analysis. Sports Medicine 2016;46:1647-1662
- Crossley KM, Stefanik JJ, Selfe J, et al. Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: Terminology, definitions, clinical examination, natural history, patellofemoral osteoarthritis and patient-reported outcome measures. British Journal of Sports Medicine. 2016;50:839-843
- Crossley KM, van Middelkoop M, Callaghan MJ, et al. 2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions (exercise, taping, bracing, foot orthoses and combined interventions). British Journal of Sports Medicine 2016; 50:844-852.
- Liao TC, Yang N, Ho KY, Farrokhi S, Powers CM. Femur Rotation Increases Patella Cartilage Stress in Females with Patellofemoral Pain. Medicine in Science and Sports and Exercise Medicine. 2015;47(9):1775-80.
- Wirtz AD, Willson JD, Kernozek TW, Hong DA. Patellofemoral joint stress during running in females with and without patellofemoral pain. Knee 012 19(5):703-8.