Ultrasound Knee

An ultrasound of the knee visualizes superficial soft tissues in real time: tendons (patellar, quadriceps), bursae, joint effusion, synovial thickening, Baker’s cysts, and some ligament or extensor mechanism tears. It detects fluid, inflammation, cysts, and guides aspiration or injections. It is limited for deep intra‑articular structures (menisci, cruciate ligaments) and bone/cartilage—MRI is preferable for those.

Yes. Knee ultrasound is a safe, non‑radiation, bedside tool for assessing soft tissues: tendons, nearby ligaments, bursae, joint effusions, synovitis, Baker’s cysts, and for guiding injections or aspirations. It’s limited for deep intra‑articular structures and detailed bone or cartilage evaluation—MRI is preferable for cruciate ligaments and cartilage. Accuracy depends on operator skill and equipment quality.

Ultrasound can detect many superficial knee problems—effusions, Baker’s cysts, tendon and collateral ligament tears—and is useful for guided procedures. However, it’s limited for intra‑articular structures: meniscal and cruciate ligament tears are often missed. MRI remains the preferred test for suspected internal knee derangement. Ultrasound’s accuracy is operator‑dependent, so imaging choice depends on clinical suspicion.

Knee ultrasound is very safe and non‑invasive, with no ionizing radiation. Risks are minimal: mild discomfort from probe pressure, rare skin irritation or allergic reaction to the gel, and theoretical thermal/cavitation effects (not typical at diagnostic settings). If ultrasound guides a needle (aspiration or injection), added risks include infection, bleeding or nerve injury. It may also miss deep bone injuries, requiring further imaging.

Yes. Knee ultrasound can detect many features of arthritis, including joint effusion, synovial thickening and inflammation, cartilage defects, increased Doppler blood flow, and some osteophytes. It is useful for diagnosing inflammatory arthritis and guiding injections. However, it is operator dependent and less effective than X‑ray or MRI for deep bone changes and joint space narrowing, so it complements clinical exam and other imaging.

Ultrasound is generally much cheaper than MRI. Ultrasound exams commonly cost a fraction of MRI fees—often tens to a few hundred dollars versus hundreds to several thousand for MRI—because ultrasound equipment is less expensive, procedures are quicker, portable, and require less infrastructure and operating cost. MRI’s high purchase, maintenance, and staffing costs make it substantially more expensive for most indications.