Pain in the anterior knee joint

Anterior knee pain Anterior knee pain refers to pain that is localized in the anterior or central portion of the knee joint. The following conditions can be considered as causes:

Patellofemoral pain syndrome.
Osgood-Schlatter disease.
Sinding-Larsen-Johanson syndrome.
Synovial fold syndrome.
Hoff's disease.
Damage to articular cartilage.
Oncology. Most patients will experience pain in the area where the tumor is located. The pain can intensify during physical activity and often makes itself felt at night. The bone mass around the tumor becomes weaker, and bone fracture may result.
Osteochondritis dissecans.
Patellofemoral instability/subluxation.
Stress fracture of the patella. A stress fracture of the patella is caused either by fatigue from submaximal stress loads or by failure where the bone has previously been weakened due to physiological stress. Decreased shock-absorbing capacity due to repeated loads leads to stress fractures.
Patellar tendonitis.
Patellofemoral osteoarthritis.
Anserine bursitis of the knee joint. The anserine bursa is one of many bursae surrounding the knee joint and is located under the pes anserine. Patients with anserine bursitis often complain of spontaneous pain and tenderness on palpation of the inferomedial surface of the knee joint.
Quadriceps tendinopathy.
Prepatellar bursitis.
Iliotibial tract syndrome.

Epidemiology/Etiology

The etiology of anterior knee pain (AKP) is multifactorial and not well defined due to the variety of symptoms, location of pain, and level of pain experienced by the patient. The underlying factors may be patellar abnormalities, muscle imbalances, or weakness that cause the patella to malalign when the knee joint flexes and extends. This also includes overuse and related conditions: tendinopathy, insertional tendinopathy, patellar instability, chondral and osteochondral damage.

Causes of bone growth under the knee

The following are the main factors that contribute to the growth of bone tissue:

Prolonged physical activity accompanied by strong pressure on the kneecap area (teenagers and professional athletes often face this problem).
A pathology that is accompanied by severe pain, swelling and tension in muscle tissue.
Genetic predisposition.
Arthritis and arthrosis.

Pain when a growth occurs may be absent, constant or intermittent, and occur only during physical activity.

Characteristics/Clinical picture

Knee pain!
What to do? Diagnostics. Yuri Sdobnikov There is no clear definition of pain in the anterior knee joint, since patients may present with various symptoms. Functional deficits, crepitus and/or instability may occur. In daily activities, pain often occurs or worsens when walking down stairs, squatting, pressing the clutch pedal in a car, wearing high-heeled shoes, or sitting for long periods with bent knees. Patients may also experience instability, especially when walking up and down stairs or across ramps. People with overuse injuries may report a feeling of instability or giveness, likely due to neuromuscular inhibition due to pain, muscle weakness, or patellar or joint instability.

Causes of knee pain

The causes of knee pain can be very different. The future mobility of the knee often depends on how timely qualified medical care was provided. There are a number of diseases, the presence of which is indicated by pain symptoms in the knee joint.

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Pain due to chronic disease

The following clinical manifestations are typical for arthrosis of the knee joint:

stiffness in the joint after waking up;
crunching sound when moving;
limitation of joint mobility;
pain when walking, getting out of a chair, going up and down stairs.

Pain in this disease does not bother you only when the knee joints are at complete rest.

Osteoarthritis of the knee joint in most cases occurs in patients over 45 years of age and is characterized by the following symptoms:

swelling of the diseased joint;
pain when moving;
joint discomfort; mild pain that increases as the disease progresses.

The following clinical manifestations are characteristic of rheumatoid arthritis:

severe pain in the knee even with a light touch;
swelling of the joint, its redness, local increase in temperature;
change in the shape of the affected joint.

More about rheumatoid arthritis

Gout, which occurs due to the buildup of uric acid in the body, can also cause severe pain and redness in one or both knee joints. If left untreated, your knees may hurt for several weeks or months.

Pain due to exercise

Causes of knee pain due to excessive exercise include the following:

chronic microdamage to cartilage - pain in the normal state is practically not manifested, but increases significantly when jogging or fitness;
dislocation of the patella - is a professional injury of dancers and athletes, manifested by severe pain, inability to move the leg, deformation of the joint and its increase in size;
damage to the meniscus, as well as sprain, rupture of the ligaments around the knee joint - occurs due to an unsuccessful sharp turn or squat and is manifested by sharp pain inside the joint; inability to move the leg, the knee hurts when bending and, especially, when extending; swelling appears;

Pain due to disorders in the vascular system

Insufficient blood circulation in the knee joint and the tissues that surround it is the cause of aching pain in the knee, which intensifies when the weather changes.

Diagnostic methods

Knee Testing (Photo from Knee Treatment Workshop)
Assessing anterior knee pain is challenging because the pain can be nonspecific and the differential diagnosis is broad. This requires a thorough examination, analysis of symptoms, in-depth knowledge of the associated structures and typical injuries. Assessing the growth and development of young people is also important for making a diagnosis.

Diseases of the hip joint and lumbar spine can provoke knee pain and should be excluded.

Some key factors to consider when making a diagnosis:

localization of pain, its nature, onset and duration, how it manifests itself during movement and at rest (at night), factors that increase and decrease pain;
trauma (acute macrotrauma, repetitive microtrauma, recent/remote);
mechanical symptoms (blocking, instability, worsening during or after physical activity);
symptoms of inflammation such as morning stiffness, swelling;
the effectiveness of previous treatment and the patient’s current level of functional activity: is there a history of gout, pseudogout, rheumatoid arthritis or other degenerative joint diseases.

The use of instrumental diagnostic methods, such as ultrasound and magnetic resonance therapy, are excellent ways of differential diagnosis and identification of intra-articular pathologies.

Thus, diagnosis and choice of treatment tactics are quite labor-intensive procedures. The European College of Rehabilitation has developed guidelines that should lead to simplified choice of therapy and, ultimately, improved treatment outcomes.

They offer the following evaluation options:

Symptoms: (1) pain (location and type) or (2) instability problems.
Lower extremity configuration: (1) asymmetrical patella, (2) high Q angle, (3) genu valgus, (4) knee recurvation, (5) subtalar joint pronation.
Patellar position: (1) patellar high, (2) patellar low, (3) patellar displacement, (4) patellar inclination, (5) patellar rotation.
Muscles and soft tissues: (1) wasting of the vastus medialis, (2) imbalance between the vastus medialis and vastus lateralis, (3) weakness of the knee extensors and hip flexors and abductors, (4) tightness of the medial patellar retinaculum, ( 5) tension in the lateral muscle structures, hamstrings and/or rectus femoris.
Knee function (pain and/or changes in the trajectory of the patella): during various types of physical activity, such as walking up stairs, exercises on a step platform, and single-leg squats.

The Kujala Anterior Knee Pain Scale (AKPS), which was developed for patients with anterior knee pain, can be used to screen for patellofemoral pain in adolescents and young adults. Ittenbach et al suggest that this questionnaire is highly reliable ( it has shown good test-retest reliability), but it is not without limitations and further research is needed into its use outside the clinical environment and in the general population.

The Lower Extremity Functional Scale (LEFS) is an additional self-assessment test to assess the patient's difficulty in physical activity. This scale is less specific for patients with BPACS than the AKPS questionnaire described above, however, it also has high test-retest reliability.

Choice of treatment tactics

In the presence of a bony abnormality or dysfunction of the patellar retinaculum, conservative treatment may be less successful. However, surgical treatment should only be considered when individuals with correctable anatomical abnormalities have failed conservative therapy.

Physical therapy

Knee Mobilization Technique
To achieve long-term results, you must first correct postural imbalances and altered movement patterns before moving on to a strengthening program. When assessing functional impairment and compensatory patterns, the entire lower extremity should be tested. Significant discrepancies in leg length should be corrected as this is a precipitating factor. Eng et al. believe that for patients with BPACS, orthosis along with exercises gives better results compared to exercises alone. However, any exercise and/or stretching program should be individualized depending on the symptoms and movement dysfunctions present.

If the patellar retinaculum is tight and negatively affecting the patellofemoral joint, manual techniques and McConnell knee taping can be used. There is evidence that knee taping combined with exercise provides superior pain reduction compared to exercise alone. Treatments such as proprioceptive training, taping and orthotics are best used as an adjunct to traditional physical therapy—research shows they are not as effective when used alone.

Improving eccentric muscle control is more effective than concentric exercises. Moreover, exercises in a closed kinematic chain are more functional and minimize the load on the patellofemoral joint. Patients with BPACS show decreased knee extensor strength as well as vastus medialis strength, although Witvrouw et al. came to the conclusion that the vastus medialis muscle cannot work in isolation. Vastus medialis weakness is thought to be caused by neuromuscular dysfunction.

The length of the hamstrings, the gastrocnemius and rectus femoris, influences patellofemoral mechanics. Tight hamstrings lead to increased reaction force at the patellofemoral joint level, since in this case the quadriceps muscle works with greater force. Therefore, regular stretching of hamstrings is recommended.

However, according to Mason et al, who compared the effectiveness of stretching exercises, quadriceps strengthening exercises, and taping (isolated and in combination), isolated stretching and quadriceps strengthening resulted in better results than taping. They also concluded that a combination of these techniques is recommended as an initial approach to treating patellofemoral pain, but that further individualized treatment is more functional. Global treatment is also important.

Conclusion

Anterior knee pain is a symptom, not a diagnosis. Making a diagnosis requires taking into account many pathologies that may be suspected during the analysis of the clinical picture and testing of the patient. There is also a high correlation between BPACS and hip biomechanical impairment, so any assessment must include the entire kinetic chain. Treatment is highly individualized and the European Rehabilitation College guidelines are a useful tool for choosing a non-operative treatment protocol.