Patellofemoral pain is the preferred term used to describe pain in and around the patella. There are numerous factors that may contribute to the development of such symptoms and can be further categorised as extrinsic or intrinsic.
Extrinsic factors concern the load created by the body’s contact with the ground (ground reaction force) and is therefore modified by body mass, speed of gait, surfaces and footwear.
During weight-bearing activities, any increase in the amount of patellofemoral load (e.g. higher training volume, increased speed of running, hill running, plyometrics), may overload the patellofemoral structures sufficiently to initiate a painful process.
Intrinsic factors, or local factors is recognised as those related to movement of the patella within the femoral trochlea : patella tracking.
Remote Contributing Factors
The following may also contribute to the development of patellofemoral pain :
* increased femoral internal rotation
* increased knee valgus
* increased tibial rotation
* increased subtalar pronation
* inadequate flexibility
Local Contributing Factors
Local factors may also contribute to the development of patellofemoral pain :
* patella position
* soft tissue contributions
* poor neuromuscular control
Treatment of Patellofemoral Pain
1. Immediate reduction in pain
This may require some or all of the following : rest from aggravating activities, ice, anti-inflammatory medication, electrotherapy (e.g. ultrasound), soft tissue mobilisations, dry needling, acupuncture. Taping can also provide an immediate pain-relieving effect.
2. Addressing extrinsic contributing factors
Whilst initially it is vital to advise the patient to reduce the load on the patellofemoral joint, as rehabilitation progresses, it is essential that any extrinsic factors that may have been placing excessive load on the patellofemoral joint (e.g. training, shoes, surfaces) are discussed and modified if necessary.
3. Addressing intrinsic contributing factors
Remote intrinsic factors may be addressed through hip muscle retraining, improving musculotendinous compliance or fot orthoses. Local intrinsic factors may be addressed with techniques such as patella taping or bracing, improved soft tisue compliance and quadriceps strengthening.
The aim of taping is to correct the abnormal position of the patella in relation to the femur. Patella taping reduces patellofemoral pain sunstantially and immediately.
Patella taping effects are assessed immediately using a pain-provoking activity such as a single or double leg squat. However, if patients are able to perform strengthening exercises pain-free without tape, then exercises alone will usually correct the abnormality.
Some braces are commercially available to maintain correct patella position and reduce patellofemoral stress.
Patellar tendinopathy was first referred to as ‘jumpers knee’ , due to its frequency in jumping sports. However, the condition also occurs in sportspeople who change direction, or who do not carry out excessive jumping activities within their sport.
The patient complains of anterior knee pain, aggravated by activities such as jumping, hopping and bounding. The most common site of tendinopathy is the deep attachment of the tendon to the inferior pole of the patella. The tendon is tender on palpation either at the inferior pole or in the body of the tendon.
It is essential that the practitioner and the patient recognize that tendinopathy that has been present for months may require a considerable period of treatment associated with rehabilitation before symptoms disappear. Conservative management of patellar tendinopathy requires appropriate strengthening exercises, load reduction, correcting biomechanical faults, and soft tissue therapy. Surgery is indicated after a considered and lengthy conservative programme has failed.
1. Relative load reduction : modified activity and biomechanical correction
There are numerous ways of reducing the load on the patellar tendon without resorting to complete rest or immobilisation. Relative rest means that the patient may be able to continue playing or training if it is possible to reduce the amount of jumping or sprinting, or the total weekly training hours.
There are numerous functional biomechanical abnormalities. Inflexibility of the hamstrings, iliotibial band and calf muscles, as well as restricted ankle range of motion, are likely to increase the load on the patellar tendon.
Interventions such as eccentric strengthening on a decline board, squats and isokinetics have been shown to reduce the pain of patellar tendinopathy. However, it should be stated that some cases can take between 6-12 months before a full functional recovery is achieved.
Soft Tissue Therapy
Techniques such as transverse frictions combined with ultrasound have been shown to reduce pain amongst patients with patellar tendinopathy.
We recommend surgery only after a thorough, high-quality conservative programme has failed. Surgeons should advise patients that while symptomatic benefit is very likely, return to sport at the previous level cannot be guaranteed, and if achieved is likely to take between 6-12 months.
Less Common Causes of Anterior Knee Pain
An inflamed plica may cause anterior knee pain. The patient typically complains of sharp pain on squatting. On examination, the plica is sometimes palpable as a thickened band under the medial border of the patella. In this case, arthroscopy should be performed and the synovial plica removed.
This is an osteochondrosis that occurs at the tibial tuberosity. This is a common condition in girls of about 10-12 years and boys of about 13-15 years, but these ages may vary. It results from excessive traction on the soft apophysis of the tibial tuberosity by the patellar tendon. It occurs in association with high levels of activity during a period of rapid growth.
Whether or not to play sport depends on the severity of the symptoms. Children with mild symptoms may continue to play some or all sport; others may choose to reduce their sporting workload accordingly. There is no definitive timescale for recovery, although it usually subsides within 12 months.
There are a number of bursae around the knee joint.The most commonly affected is the pre-patellar bursa.
Pre-patellar bursitis (housemaid’s knee) presents as superficial swelling on the anterior aspect of the knee. Treatment of mild cases of bursitis includes ice application and anti-inflammatory medication. More severe cases require aspiration and injection of a corticosteroid. If despite these measures, there are several recurrences, surgical bursectomy may be required.
Lateral Knee Pain
Pain about the lateral knee is a frequent problem, especially among distance runners. The most common conditions tend to be; iliotibial band friction syndrome; lateral meniscus abnormality, degenerative changes or a cyst formation.
Iliotibial Band Friction Syndrome
This condition occurs as a result of friction between the iliotibial band and the underlying lateral epicondyle of the femur. It is a common condition among distance runners, where the friction or impingement occurs near foot strike, or foot contact phase with the ground. Studies have shown that runners with this condition have significant weakness of their hip abductors in the affected limb.
The patient complains of an ache over the lateral aspect of the knee, aggravated by running. Longer runs or those downhill or on cambered courses are particularly aggravating.
On examination, tenderness is elicited over the lateral epicondyle of the femur, just above the joint line. Crepitus may also be felt and repeated flexion/extension of the knee may reproduce the patients symptoms.
Ober’s Test may reveal ITB tightness which may be a secondary condition. There can also be palpable trigger points along the body of the ITB which can also contribute to the symptoms.
* Activity modification. Avoid all pain-provoking exercises.
* Ice, anti-inflammatory medication, interferential therapy, ultrasound
* Corticosteroid injection into the bursa between the ITB and the lateral epicondyle reduces pain in acute cases
* Soft tissue therapy to correct tightness of the ITB. Trigger point treatment. Self-massage with foam roller.
* Frequent stretching of the ITB
* Strengthening of the gluteals / hip abductors
* Biomechanical abnormalities such as excessive sub-talar pronation should be corrected
* Surgery to release the ITB and excise the bursa may be indicated if conservative management fails.
* Resume running when there is no local tenderness and the strengthening exercises can be performed without pain. Initially run on alternate days and avoid downhill running.
Lateral Meniscus Abnormality
Degeneration of the lateral meniscus can also present as gradual-onset lateral knee pain. The meniscus is typically tender along the joint line, 2-3 cm below the site of tenderness at the ITB. A positive McMurray’s test can help confirm any suspicion of meniscal pathology. It is also worth noting that a degenerate meniscus can present as a painful or non-painful lump at the lateral joint line.
Osteoarthritis of the Lateral Compartment of the Knee
Lateral knee pain can also be caused by degeneration of the lateral tibial plateau and this is often found in conjunction with meniscal injury. As the disease progresses, the patient experiences pain at night that may disturb sleep associated with morning stiffness.
Initial treatment of osteoarthritis includes symptomatic relief with painkilling and anti-inflammatory medication, exercise prescription and weight loss if indicated. Intra-articular hyaluronic acid (Synvisc) injections have a similar effect to anti-inflammatories, but the patient does not have to take tablets daily.
Superior Tibiofibular Joint Injury
This injury may result from direct trauma or in association with rotational knee or ankle injuries. Pain occurs with activities such as pivoting or cutting. The patient may feel the pain distally at the shin and not localise it to the superior tibiofibular joint. On examination, the joint is tender and there may be restricted or excessive movement on passive gliding of the joint.
Manual mobilisation is an effective treatment for a stiff joint. Local electrotherapy may also help relieve pain. Biomechanical factors may also need to be addressed. Occasionally in patients who fail to respond to conservative measures, a corticosteroid injection may be used.
Medial Knee Pain
The main causes of medial knee pain are; patellofemoral syndrome, medial meniscus injury, degenerative changes or cyst formation.
The patellofemoral joint (as discussed before), commonly refers pain to the medial aspect of the knee.
Medial Meniscal Abnormality
In the young, adult patient, a small tear of the medial meniscus may cause a synovial reaction and medial knee pain. In the older patient, gradual degeneration of the medial meniscus can also present as pain. The patient can complain of clicking and pain on certain twisting activities, such as getting out of the car or rolling out of bed. Treatment is the same as for acute medial meniscal injury.
Osteoarthritis of the Medial Compartment of the Knee
Management of this condition involves symptomatic relief with painkilling and anti-inflammatory medication, modification of activities, exercise prescription, and weight loss if indicated. Intra-articular hyaluronic acid (Synvisc) injections can be highly effective, with beneficial effects on pain and overall function. Occasionally, bracing can off-load the aggravating aspect of the knee joint and provide symptom relief.
Pes anserinus tendinopathy / bursitis
The pes anserinus (goose’s foot) is the combined tendinous insertion of the sartorius, gracilis and semitendinosus tendons at their attachment to the tibia. The pes anserinus bursa lies between this insertion and the bone and may become inflamed.
These conditions are characterised by localised tenderness and swelling. Active contraction or stretching of the medial hamstring muscles reproduces pain. Treatment follows the general principles of tendinopathy / bursitis management. Corticosteroid injection into the bursa can be extremely effective.
This is a disruption of the femoral origin of the medial collateral ligament with calcification at the site of injury. This syndrome is an important cause of knee stiffness. The patient complains of difficulty straightening the leg and twisting.
Examination reveals marked restriction in knee joint range of motion with a tender lump in the proximal portion of the medial collateral ligament. Treatment consists of active mobilisation of the knee joint and infiltration of a corticosteroid to the tender medial collateral attachment if pain persists.
Other causes of medial knee pain
The medial collateral ligament may also become inflamed as a result of activities that put a constant valgus strain on the knee, such as swimming breaststroke. This condition is commonly referred as ‘breaststrokers knee’, and is actually a first degree sprain of the medial collateral ligament, or inflammation of the medial collateral ligament bursa due to excessive stress. Finally, a synovial plica may also present as medial knee pain.
Posterior Knee Pain
The main causes of posterior knee pain are referred pain from the lumbar spine, tendinopathies or cyst formation.
Posterior knee pain precipitated by acceleration or deceleration when running and when kicking, is likely to be biceps tendinopathy or popliteus tendinopathy. Pain described as a poorly localised dull ache not directly related to activity suggests referred pain from the lumbar spine.
The main clinical finding is tenderness on palpation along the proximal aspect of the tendon. Resisted knee flexion in external tibial rotation will be painful in popliteus injuries.
Treatment includes strengthening of the tibial rotators and hamstring muscles. Massage therapy and mobilsation may help to correct any restriction of tibial rotation or knee flexion. Posterior knee structures, especially the hamstring muscles, should be stretched. Anti-inflammatory medication, ultrasound and interferential therapy may prove useful adjuncts to rehabilitation.
Patients who fail to respond to the above regimen may be helped by a corticosteroid injection posteriorly into the point of maximal tenderness.
This may result from excessive hill running or a rapid increase in mileage. Examination may reveal local tenderness and reproduced pain on calf raising, jumping or hopping. Treatment consists of ice, electrotherapy, soft tissue therapy, and importantly, a graduated stretching / strengthening programme.
This is a chronic knee joint effusion that herniates between the two heads of the gastrocnemius muscle. It occurs most commonly secondary to degenerative or meniscal abnormality. The amount of swelling may fluctuate and examination findings are a swollen, tender mass over the posterolateral joint line.
Occasionally the cyst may rupture, leading to lower leg swelling simulating venous thrombosis. A ruptured cyst usually displays a ‘crescent sign’ – a bruised area around the ankle. Treatment of the Baker’s cyst involves treatment of the associated abnormality.