ANTERIOR KNEE PAIN:
In this blog we look into pain that is specific to the front of the knee, otherwise termed Anterior Knee Pain (AKP). AKP is an umbrella term that brackets pain residing at the front (anterior) part of the knee. Injury diagnosis of anterior knee pain is normally chronic in nature and characteristically falls under:
- Patella Tendinopathy
- Patello-Femoral Pain (PFP)
- Hoffa’s Fat Pad Impingement
All three diagnosis’ can be sensitive to changes in load and tissue homeostasis. In addition, the retinaculum (connective tissue), joint capsule, synovial fluid and bone surface can all cause an inflammatory response due to the vascularisation of the structures when tissue homeostasis is disrupted. Albeit the different injuries, all which require a different treatment plan; a thorough assessment and diagnosis of the painful structure is the first step towards reducing knee pain.
Predisposing factors that can attribute to anterior knee pain include:
- Lower limb biomechanics
- Tibial rotation
- Patella alignment
- Patella stability (patella alta)
- Muscle strength
- Myofascial length
- Muscle endurance
- Neuromuscular control
- Obesity
- Osteoarthritis
Certain triggers or factors which can influence load, therefore predispose to injury are separated into two:
- Intrinsic factors; training frequency, intensity, type (load exposure)
- Extrinsic factors; illness, operation, equipment, holidays, surface quality, genetics etc
These factors induce tissue stress, which can be positive or negative towards the injury. They can be modifiable e.g. training load, or non-modifiable e.g. genetics. What we can focus on remodelling is the modifiable factors which influence knee pain.
Evidence supporting altered loading:
- Limb alignment
- Q angle (Angle between hip to knee) in standing double leg vs single leg vs opposite leg
- There is a correlation that people with PFP have a higher Q angle standing on one leg compared to their non painful side
- Increased Q angle can cause a lateralisation glide of patella; essentially the ‘line of pull’ at the knee cap to the lateral side alters normal loading.
- An increase Q angle may create more tightness of the lateral hip and thigh muscles, thus increasing lateral pull of the patella
- Effect of hip adduction/valgus
- Greater ITB load increases anterior tibial translation (shin bone sliding forward), valgus tibial angulation (inward angle at the shin bone) and decreases the amount of internal tibial rotation (inward rotation at the shin bone)
- Lateral patella translation increases as knee external rotation increases
- A weak hip abductor to adductor strength ratio may result in the thigh adducting further than what is considered normal, thus increasing valgus force on the knee
- Poor muscular endurance of the hip abductors and external rotators can result in the thigh rotating into too much internal rotation and adduction, thus causing shear valgus force on the knee much later on in the sport or activity
- Knee flexion:
- People with anterior knee pain run with less knee flexion
- People with anterior knee pain go downstairs with more trunk flexion instead of knee/hip flexion
- Pain is normally provoked when sitting to standing or climbing up or down stairs
- There is localised tenderness around the knee cap region
- There is minimal swelling seen
- Wearing high heels tends to worsen the knee pain
- Quads inhibition -> quads dyskinesia (due to weakness or pain or both) usually occurs eccentrically (when the muscle is lengthened) at approximately 60 degrees and 90 degrees however quads inhibition can occur throughout all or other parts of knee range due to contact point of Patella on the Femur and Tibia.
- Pain on knee flexion under weight usually represents PFP and treated differently to patella tendinopathy and fat pad impingement
- Knee extension:
- Pain at end range knee extension normally predicts fat pad impingement
- Reducing valgus and hyper extension stance can significantly help reduce pain and discomfort. This can be done via a range of ways pending its cause
- Placing heel ‘wedges’ into shoes to put the knee into more flexion will greatly reduce pain and discomfort at the anterior knee
- Taping the knee to lift the patella off the fat pad can reduce the inflammatory cycle caused by continuous impingement
- Use mirrors and tape to give feedback on knee position both tactilely and visually. You want to minimise knee valgus and hyper extension
- Exercising quadriceps strength in shallow degrees of knee flexion; approximately 10-30 degrees to ensure activation of the VMO muscle and posterior fibres of the Gluteus Medius muscle.
- There is usually some swelling noted around the fat pad region, and icing can help reduce inflammation, pain and swelling of the region.
- If it is fat pad impingement, standing or walking on flat surfaces usually creates soreness and pain
- Wearing high heels tends to reduce knee pain in fat pad impingement as it brings the knee into more bend / flexion
All the above can significantly affect your participation in sport or recreational activities such as running or group High Intensity Interval Training (HIIT) classes. Without changes to some of the factors above, such as load exposure and biomechanics; further tissue strain and inflammatory damage can occur, thus causing increased pain and muscle inhibition. This creates a negative cycle of pain, continued tissue damage and increased muscle wastage; forever making it harder to exercise, and conversely harder to manage the pain and rehabilitate/recover from.
If this sounds like you, or someone you know then share this blog with them so that they too are educated and have an opportunity to work with us. To ensure you are getting the best in assessment and treatment planning, book a consultation with us so we can address how best we can assist you in the recovery of your knee pain.
