Knee ultrasound

Before the knee ultrasound examination

Before performing an ultrasound examination of the knee, the orthopedic surgeon or radiologist conducts a detailed interview with the patient regarding the characteristics and location of pain symptoms. Chronic knee pain most often results from a degenerative disease or soft tissue overload caused by sports or work. A systemic disease such as rheumatoid arthritis or psoriatic arthritis may also cause chronic knee pain with periods of exacerbation and remission. Acute sudden pain in the knee is usually associated with an injury. In order to focus the ultrasound examination on specific structures of the joint, it is necessary to determine the circumstances of the injury, the possible direction of the traumatic force and the nature and dynamics of the symptoms after the injury (pain, swelling, blockage of the knee movement). Diffuse pain is more often associated with damage to intra-articular structures or arthritis, while local superficial pain is usually associated with pathologies of collateral ligaments or tendons of muscles surrounding the knee joint.

During the examination, the doctor assesses the contours of the joint and the range of motion in relation to the opposite limb. If necessary, it performs specific tests to indicate the presence of damage to specific structures of the knee joint. The ultrasound examination may also be preceded by the assessment of radiographs of the knee, if they were previously taken.

What conditions and injuries can be diagnosed with ultrasound of the knee?

Below are listed the most common pathologies of the knee joint, which can be partially or completely assessed during knee ultrasound.

Pain in the middle of the knee or general diffuse knee pain:

• Damage to the meniscus (visible on ultrasound to a limited extent),
• Injuries of the anterior cruciate ligament ACL and posterior cruciate PCL (visible to a limited extent, most often MRI of the knee is necessary),
• Degeneration of the knee joint (partial assessment of the cartilage of the femoral block),
• The presence of free bodies in the joint (partially),
• Synovitis of the knee,
• Blood and fat discharge into the joint,
• Some tumors on the knee joint.

2. Pain in the front of the knee:

• hamstring tendinopathy of the thigh,
• acute damage to the quadriceps tendon,
• pathological changes of the patellar ligament (e.g. jumper's knee),
• medial synovial fold syndrome,
• prepatellar bursitis,
• deep and superficial postpatellar bursitis,
• damage to the patella straps.

3. Pain in the medial side of the knee:

• damage to the medial colateral ligament (MCL),
• damage to the medial meniscus,
• goose foot tendinopathy,
• goose foot bursitis.

4. Pain in the side of the knee:

• damage to the lateral colateral ligament (LCL),
• iliotibial band friction syndrome (runner's knee),
• ganglions of the tibiofibular joint.

5. Pain in the back of the knee / vascular pathologies:

• Baker's cyst,
• periarticular ganglions,
• semimembrane bursitis,
• damage to the hamstring muscle of the thigh,
• cruciate ligament ganglions,
• popliteal aneurysms (Doppler ultrasound),
• popliteal entrapment syndrome (ultrasound doppler).

Other:

Compression neuropathy of the peroneal nerve in the area of ​​the arrowhead (symptoms present at the level of the foot).

The knee ultrasound cannot assess:

• Cartilages 1/3 of the femoral block,
• Tibia cartilage,
• Patellar cartilage (including chondromalacia of the patella),
• Edema of the bone marrow, endosseous changes.

If cartilage or chondro-bone damage is suspected, an MRI of the knee must be performed.

How is the knee ultrasound performed?

Standard ultrasound of the knee joint includes the evaluation of the following compartments of the knee: anterior, lateral, medial and posterior. During the examination, the patient lies on his back with the limb extended or bent at the knee. Your doctor may ask you to rotate the limb outward or inward. When examining the structures of the popliteal fossa, the patient lies on his stomach.

The dynamic test is based on the assessment of selected structures during stress tests, movement in a joint or during muscle activity. The efficiency of the knee collateral ligaments is most often assessed, e.g. during the valgus test, the MCL collateral ligament is assessed. Post-traumatic tendons and muscles are examined at rest and when the muscles are tense. Dynamic knee ultrasound provides important information on the morphology of the examined structures under conditions similar to the functional loading of the joint.

Knee sonosurgery

Sonosurgery is the term for a procedure that is performed under the control of ultrasound. The most common treatment is an injection. Monitoring the position of the needle on the ultrasound image enables precise administration of a given substance to the diseased area. Sonosurgery is also used during Baker cyst puncture, which allows it to bypass important vessels and nerves in the popliteal fossa. Performing procedures under ultrasound control increases the effects of treatment and minimizes the risk of complications.

At the Dworska Hospital in Krakow, we perform ultrasound examinations on modern USG 4D, USG 3D General Electric® machines of the Voluson® series.

Frequently asked questions about knee ultrasound: