Vastus Medialis Myofascial Pain Syndrome

Disclaimer: Please read the Disclaimer at the bottom of this page.
Copyright © Educom Pty Ltd: All material on this website (including the text, graphics, videos and downloadable files) is owned by or licensed to Educom Pty Ltd and is subject to copyright and other intellectual property rights under international conventions

Vastus Medialis Myofascial Pain Syndrome

Vastus Medialis Myofascial Pain Syndrome is a common but often underdiagnosed cause of referred pain to the anteromedial aspect of the knee and lower thigh. Myofascial pain syndromes are frequently overlooked because their trigger points are typically located away from the area where pain is experienced, making them easy to miss during a standard physical examination.

The vastus medialis is one of the four muscles comprising the quadriceps femoris group, along with the vastus lateralis, vastus intermedius, and rectus femoris. It is located on the medial aspect of the thigh, featuring a broad muscle belly that tapers into its tendon.

The vastus medialis originates from the lower portion of the intertrochanteric line, the linea aspera of the femur, and the upper part of the medial supracondylar line. It inserts into the medial border of the patella via its tendon and ultimately attaches to the tibial tuberosity through the patellar ligament.

This muscle is primarily innervated by the femoral nerve, which carries fibers from spinal levels L2, L3, and L4, originating from the lumbar plexus.

The primary function of the vastus medialis muscle is knee extension, which is essential for activities such as walking, running, and jumping. The muscle includes a specialized subdivision known as the vastus medialis obliquus (VMO), which plays a critical role in stabilizing the patella and ensuring proper tracking within the femoral groove, particularly during the early phases of knee extension.

Dysfunction or weakness in the vastus medialis, especially the VMO, can lead to various knee problems, including patellofemoral pain syndrome, patellar instability, and anterior knee pain. As a result, strengthening exercises targeting the vastus medialis, with a focus on the VMO, are commonly incorporated into rehabilitation programs for these conditions.

Additionally, myofascial pain syndrome affecting the vastus medialis can disrupt normal biomechanics, potentially contributing to patellar malalignment or dysfunction, further exacerbating knee-related issues.

Vastus Medialis Myofascial Pain Syndrome

Myofascial pain is a common condition and a frequent reason for visits to primary care physicians and pain clinics. Research has shown that myofascial pain syndromes are associated with various pain conditions, including neck pain, lower back pain, extremity pain, and headaches.

In the case of the vastus medialis muscle, trigger points can refer pain to the medial aspect of the anterior knee. These trigger points may be located anywhere within the muscle or its fascia, making a thorough examination of the entire muscle essential. However, based on clinical experience, certain areas within the vastus medialis are more commonly affected, as illustrated in the image below.

Myofascial Trigger Points – A myofascial trigger point is a contraction knot found within a band of a muscle or in the muscle’s fascia. This contraction knot is considered to be responsible for nodularity which can be detected by palpation. Previous publications have suggested that trigger points are found in specific locations within a muscle. However, more recent publications suggest that they can be found anywhere within a muscle. Therefore, the entire muscle should be thoroughly examined in order to locate them.

Diagnostic Criteria for Myofascial Trigger Points – A 2019 international consensus concluded that moderate to excellent reliability for the presence of myofascial trigger points is based on the combination of a taut band, tender spot, local twitch response, and referred pain. The consensus was that at least two of these criteria are required for a myofascial trigger point diagnosis.

Taut Band and Tender Spot – Myofascial trigger points typically involve an exquisitely tender spot found within a taut band of the muscle or in the muscle’s fascia.

Local Twitch Response – A local twitch response is defined as a quick visible or palpable contraction of the muscle fibers when pressure is applied to a taut band of a trigger point.

Active and Latent Trigger Points – Myofascial trigger points can be classified as active or latent. An active trigger point is one that reproduces or intensifies the patient’s familiar (referred) pain when it is compressed. A latent trigger point is one that does not reproduce the patient’s familiar pain when it is compressed.

Referred Pain –  A key feature of an active trigger point is the presence of referred pain which is a manifestation of central sensitisation. This central sensitization results in a spread of perceived pain to distant and larger areas of the body than just the local tenderness found at the taut band.

Research suggests that the combination of acidic pH and pro-inflammatory mediators at the active trigger point contributes to the segmental spread of nociceptive input into the dorsal horn of the spinal cord. The dorsal horn neuron, in turn, sensitizes the central nervous system by transmitting nociceptive impulses superiorly to activate the somatosensory cortex where pain information is perceived and interpreted. This is believed to cause hyperalgesia and referred pain.

Risk Factors –  Many different activities and medical conditions may place individuals at greater risk for developing myofascial pain syndrome. These include:

• Joint hypermobility or ligamentous laxity (i.e., when the ligaments are unable to provide joint stability, muscles remain in constant contraction to stabilize the joint. This is believed to cause the formation of trigger points within muscles)
• Musculoskeletal injuries
• Unaccustomed or intense exercise
• Muscle overload or repetitive physical activity
• Prolonged incorrect posture (e.g., poor ergonomics or habitual postures)
• Cold drafts or an intense cooling of muscles (e.g., sleeping in front of an air conditioner or under a ceiling fan)
• Lack of sleep or poor sleep
• Leg length inequality or other biomechanical disturbances
• Psychological stress, anxiety, and depression
• Fatigue

• Deep, aching pain localized to the anteromedial knee is often described as persistent discomfort.
• Pain may also radiate to the anteromedial lower thigh.
• Nighttime pain is frequently described as a deep ache, which may disrupt sleep.
• Occasional knee buckling during walking, leading to a sensation of instability.
• Reported weakness in the knee, particularly noticeable when descending stairs.
• Pain relief is often achieved through stretching of the quadriceps muscles.

• There is a slight restriction in the range of motion during knee flexion.
• Palpation identifies one or more trigger points within the vastus medialis muscle, characterised by at least two of the following: a taut band, a tender spot, a local twitch response, and/or referred pain.
• Trigger points are most commonly located in the middle and distal portions of the muscle.

Imaging is generally not necessary for diagnosing Myofascial Pain Syndrome but may be utilised to rule out other potential underlying conditions.

The following are examples of “red flags” for patients presenting with knee pain:

• History of a significant injury
• Severe pain
• Unrelenting pain
• Nocturnal pain
• Unexplained weight loss
• Fever
• Deformity
• Large joint swelling
• Significant loss of range of motion
• Significant neurological impairment
• Severe tenderness on palpation or severe pain with any examination procedure

If any red flags are identified during history taking and clinical examination, referral for urgent medical evaluation and further investigation is warranted.

Chilled Muscles and Myofascial Pain Syndrome

• Prolonged exposure of muscles to cold drafts (e.g., sleeping in front of an air conditioner, under a ceiling fan, or leaving hair wet after a shower) is a recognized risk factor for developing myofascial pain syndrome. Patients are often unaware that muscle chilling can contribute to the onset of their pain. As a result, practitioners must inquire about any recent exposure to cold drafts when evaluating patients with myofascial pain. Identifying this potential trigger can aid in diagnosing and preventing symptom recurrence.

Ultrasound Therapy for Myofascial Pain Syndrome

• Based on our clinical experience, many patients with myofascial trigger points respond well to treatment with ultrasound therapy, including ultrasound phonophoresis, applied directly to the trigger points. This therapy aims to disperse the accumulation of congestion, such as lactic acid and other inflammatory chemicals, which are often associated with trigger points.
• Compared to myofascial release techniques (described below), ultrasound offers several advantages: it is non-painful for the patient, can target trigger points at deeper tissue levels, and may accelerate the recovery process.

Myofascial Release Technique

When performing the myofascial release technique, follow these steps:

• Step 1: Start by applying gentle pressure to the trigger point and gradually increase it until the patient experiences mild local pain (you will feel an increase in tissue resistance). Hold this pressure steady without increasing it further until the patient reports that the pain has subsided (you will also notice a reduction in tissue resistance).
• Step 2: Once the initial pain has subsided, gradually apply deeper pressure to the trigger point until the patient again reports local pain (you will once again feel an increase in tissue resistance). Maintain this pressure until the patient indicates that the pain has eased.
• Step 3: After the second easing of pain, apply an even deeper pressure to the trigger point until local pain returns (you will feel an increase in tissue resistance). Continue to hold this pressure until the patient reports that the pain has once again subsided.

Anterior Knee Pain Differential Diagnosis

In addition to vastus medialis myofascial pain syndrome, the differential diagnosis of anterior knee pain in adults should include other conditions such as:

• Rectus femoris myofascial pain syndrome (see below)
• Patellar tendinopathy
• Patellofemoral pain syndrome (also known as Runner’s Knee)
• Suprapatellar, prepatellar, or infrapatellar bursitis
• Quadriceps strain
• Tibiofemoral joint dysfunction
• Internal knee derangement
• Osteoarthritis
• Knee inflammatory joint disease
• Lumbar radiculopathy or femoral neuropathy

Rectus Femoris Myofascial Pain Syndrome

The trigger point in the rectus femoris muscle refers to pain in the anterior knee. The trigger point may be located anywhere within the muscle and its fascia. Therefore, the entire muscle should be examined thoroughly. However, based on our clinical experience, the common location for the rectus femoris trigger point is depicted in the image below.