Kneecap
Pain
There are many types
and causes of knee pain. Knee pain is thought to constitiute 41% of
chronic cycling injuries. In the last article I looked at the ITB and
pain on the outside of the knee, in this article I am going review
non traumatic pain involving the kneecap (patella). You may have
heard of the terms patallofemoral pain (PFP), chondromalacia patellae
or runners knee – all used to describe pain around or under the
kneecap.
This problem is not
limited to cyclists; athletes active in sports such as running,
skiing, football or other sports where a lot of pressure is put
through their knees can suffer with it. It is common with up to 25%
of sport participants complaining of
this type of pain.
Symptoms
Common symptoms of
patella femoral pain can include:
Pain located around or under
the kneecap noticed when cycling, prolonged sitting, stair climbing,
kneeling, hoping, running
Gradual onset, not related to
any traumatic event such as a fall, twist, or knock
Stiffness after sitting for
long periods
Crepitus or crunching noises
under the knee cap
What
causes the pain?
In order to
understand how it occurs, it is useful to understand the structure of
the knee and the kneecap. The kneecap is a triangular shaped bone
that runs in a groove formed by the thigh bone (or femur). At the top
the quadriceps tendon inserts into it, below the patellar tendon
connects it to the shin bone (or tibia) and from each side fibrous
tissue that surrounds the knee join attach to it, and from the right
side it also receives attachments from the vastus medialis (VMO).
The kneecap moves in
this groove when the knee bends and straightens. When the kneecap
does not track properly in the groove, it can rub on the sides of the
groove leading to pain and inflammation. In these cases the kneecap
tracks too laterally i.e. it tends to track more to the outside of
the knee. Due to the excessive lateral tracking, stress can also be
placed on the fibrous tissue on the inside of the knee. This can also
be a source of inflammation and pain.
Anything that
changes the way the kneecap moves in the groove can lead to
patellofemoral pain. This can include:
Muscle Imbalances
Imbalances between the muscles
on the outside (lateral quads, ITB) of the leg versus the inside
(VMO): the lateral muscles can put a stronger pull on the kneecap
than the VMO can meet, leading to weakness and strain of the VMO.
The VMO is particularly susceptible to weakening after knee injury
where the leg is immobilised or full range of knee motion is
restricted for a period of time. Sometimes clients will report a
feeling of strain or tenderness just to the top inside of the knee
which they can feel by pressing when the knee is bent. They notice
it during cycling, running or stair climbing. This can be a sign
that the VMO is weak, and if not addressed could later lead to pain
around the kneecap.
Studies have shown that tight
ITB, weak gluteus medius and abductors, weak external rotators, and
weak core can give rise to instability in the pelvis. Pelvic
instability can cause the thigh bone (femur) to rotate inward more
than usual. This might be observed as a side to side movement of
the knee when extending the leg during the downstroke, instead of
the desired linear movement of the knee as you push down on the
pedal. This changes the orientation of the groove so the kneecap
does not track in it properly leading to pain. A rough test of your
pelvic stability would be to perform a lunge or squat and note
whether the knee rolls inwards as you perform it. Your knee should
keep pointing straight and not dip or turn inwards. Or
alternatively as mentioned in the article on ITB problems, excessive
hip dipping while cycling would also be another indicator that the
gluteus medius and abductor s are weak.
Anatomical
Reasons
Increased foot pronation.
Pronation is the rolling inwards of the foot during walking or
running or cycling. Excessive pronation or over pronation can lead
to problems at the knee. While this movement happens at the foot, it
also causes a compensatory movement in the shin bone which affects
the alignment at the knee impacting the kneecap and causing pain.
The position of the shin bone,
excessive inward or outward rotation of the lower leg can affect the
alignment at the knee. It has been suggested that people with low
arches may be more susceptible to PFP than those with normal arches
as low arches change the alignment of the shin bone. The positioning
of your cleats can affect the position of the shin bone and the
rotation of the lower leg.
Leg length discrepancies: when
setting saddle height only one leg is correctly fitted
to the pedal meaning that if the bike is fitted to suit the
shorter leg, there will be increased compression of the kneecap in
the groove and pain. Leg length discrepancies can occur due to
rotations at the pelvis, or more unusually, if you were born with
them.
Bike Set up &
Training
When cycling, a saddle set to
far forward will increase the wear and tear forces on the knee and
the likelihood of knee pain. Similarly cycling with the saddle too
low will have the same effect. As mentioned above your cleat
positionng will also affect the rotation of the shin bone and
possibly impact your knee.
Training: sudden increases in
training, a lot of hill work, or cycling in high gears with low
cadence can cause problems.
What
can you do to help it?
The best thing to do
is to get assessed and treated by your Physical Therapist. They will
advise you on what needs to be strengthened, work out tight muscles,
perform mobilisations to realign the pelvis and correct leg length
if needed, tape your knee, and determine whether to refer you for
orthotics should you need them. Also consider seeing a bike fit
specialist to ensure your bike setup is optimal.
Just a note on
taping: Tape can be applied to the kneecap to put it into the correct
alignment and try and reduce pain when training or racing and is
often used as part of the rehabilitation process. Kinesio tape (the
bright blue, pink or black tape you might see people wearing) can
also be used to help align the kneecap, as well as supporting the
VMO, and reducing the tension through the tight muscles. But at the
end of the day you need to fix the root cause – muscle
imbalance, gait or feet, pelvic instability – to get longer
term relief from knee pain.
Often prevention
is better than cure so the following are worth
considering:
Prevent imbalances around the knee:
Stretch lateral quads,
hamstring, ITB (or use foam roller) and the calfs to keep all
muscles around the hip and knees flexible
If you notice strain or pain on
the inside of the knee strengthen the VMO. Also consider adding VMO
strengthening exercises to your pre season strength and conditioning
programme. See sample exercises below.
Prevent imbalances at the pelvis
Strengthen the gluteus medius.
The gluteus medius is a key muscle in maintaining pelvic stability.
See exercises below. A study was carried to research the effect of
additional strengthening of hip abductor and lateral
rotator muscles (gluteus medius) in a strengthening quadriceps
exercise rehabilitation programme for patients with the
patellofemoral pain syndrome. The first group focused on
strengthening the quadriceps muscles only, the second group
strengthened the quadriceps and the gluteus medius. After 6 weeks
the second group were found to have a better improvement in symptoms
that the first group.
Stretch or use a foam roller
for the ITB
Stretch the hip flexors. Tight
hip flexors can contribute to pelvic instability
Consider core work to improve
overall pelvic stability.
Massage
Massage can be useful to help
loosen out tight muscles such as quads, ITB, calfs and hamstrings
Use a foam roller self massage
the ITB
Training
Bike.
If you are a time trailer or
tri-athlete a forward seat height can give aerodynamic advantage but
consider adjusting seat height back to relive the forces on the knee
when training on long distance cycles.
Check your cleats and saddle
position and ensure they are not contributing to the problem.
Exercises
I have included some
sample exercises to help prevent or assist with knee pain. If you are
suffering from knee pain a therapist will tailor a more specific
rehabilitation programme for you based on your individual assessment
and requirements.
Neuromuscular
control of VMO
This exercise
ensures that the VMO is contracting correctly. This ability to
contract correctly and at the right time (called neuromuscular
control) can be inhibited by pain or swelling in the knee. Sit on the
ground with your leg outstretched in front of you. Put your hand just
above the knee and a little to the inside – this is the VMO.
Now try and bring the back of your knee to touch the floor, i.e.
straighten the leg more. You should feel your VMO contract. If not
repeat this exercise until you can feel the VMO start to contract,
and continue it until the VMO is contracting for each repetition.
Progress to trying this standing up when weight bearing on the leg so
the exercise then becomes more functional.
VMO Alphabet
Once the VMO is
contracting properly, this exercise will help to continue strengthen
it.
Sit on the floor and support
your body weight on your hands
Raise your leg approx 6 inches
(15 cm) off the floor.
Keeping your leg straight,
point you foot and using your foot as a “pen” draw the
alphabet in the air.
The movements should be small
and you should feel the VMO working as you do the exercise.
Strengthening
the gluteus medius.
See the article
on the ITB pain for pictures of the exercise.
Lie on your side with the side to be strengthened on top
Bend the lower leg slightly at the hip and knee for stability
Bring the leg backwards so it lies behind the hip.
Slowly raise the upper leg until 1-2 inches over the hip
From this position slowly lower the leg (1 repetition)
Repeat: 10-12
repetitions on each side, and build up to being able to perform 3
sets, three times a week
Note: place
your hand on the gluteus medius – this is located above and to
the outside of your jeans back pockets. You should feel the
contraction here as you raise your leg upwards. It is important to
keep the leg behind you as this localises the effort to the gluteus
medius muscle, if it comes forward to much other muscles become
involved. Also do not raise the leg much over the level of hip,
raising it higher just involves use of the back muscles and it’s
not working the gluteus medius. Add ankle weights if 3 sets can be
done easily.
Lunges or squats
When you have built
up the strength of the VMO and gluteus medius perform a lunge or
squat exercise. With weak pelvic stablisers, the knee can roll
inwards when performing a squat or lunge. The aim of this exercise is
to develop knee control and to further strengthen the quads,
abductors and gluteal muscles so that the knee does not roll inward.
When performing the exercise the ensure knee stays in line with the
toes and does not move inwards over the side of the foot. Use a wall
or stable surface for balance to help you get the movement right and
under control. Make sure to stretch quads after these exercises.
Repetitions: 10-12. No of Sets: 3, three times a week.
References:
Brukner P, Kahn
K 2007. Clinical Sports Medicine 3rd
Edn. McGraw-Hill, North Rhyde
Brushø C, lmich P, Nielsen
M, Albrecht-Beste E 2008. Acute patellofemoral pain:
aggravating activities, clinical examination, MRI and ultrasound
findings. British Journal of Sports Medicine 42,
pp.64-67
Cowan S,
Crossley K, Bennell K 2009. Altered hip and trunk muscle function
in individuals with patellofemoral pain. British Journal
of Sports Medicine 43, pp.584-588
Dierks, T,
Manal K, Hamill, J, Davis, I 2008.Proximal and Distal Influences
on Hip and Knee Kinematics in Runners With Patellofemoral Pain
During a Prolonged Run. Journal of Orthopaedic & Sports
Physical Therapy 38 pp.448-456
Fagan V,
Delahunt E 2008. Patellofemoral pain syndrome: a review on the associated neuromuscular deficits and current
treatment options. British Journal of Sports
Medicine,42, pp.789-795
Hertling D,
Kessler R 2006. Management of Common Musculoskeletal Disorders
4th edn. Lippincott Williams &
Wilkins, Philadelphia
Lin Y, Lin J,
Cheng C, Lin D, Jan M 2008. Association Between Sonographic
Morphology of Vastus Medialis Obliquus and Patellar Alignment in
Patients With Patellofemoral Pain Syndrome. Journal of
Orthopaedic & Sports Physical Therapy 38, pp.196-201
Lowry C,
Cleland J, Dyke K 2008. Management of Patients With
Patellofemoral Pain Syndrome Using a Multimodal Approach: A Case
Series. Journal of Orthopaedic & Sports Physical
Therapy 38 pp.691-702
Nakagawa
T, Muniz
T, Baldon
R, Maciel C, Menezes Reiff R, Serrão F, 2008.The
effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized
controlled pilot study. Clinical
Rehabilitation 22, pp. 1051-1060
Schwellnus MP ,
Derman EW 2005. Common injuries in cycling: Prevention, diagnosis
and Management. South African Family Practice 47, pp. 14-19
Van
Zyl E, Schwellnus M, Noakes, T 2001. A
review of the etiology, biomechanics, diagnosis and management of
patellofemoral pain in cyclists. International Sports Medcine
Journal, 2