How Genicular Artery Embolization Works
A Minimally Invasive Procedure That Is Changing How Knee Pain Is Treated
For patients in Lahore living with chronic knee pain from osteoarthritis who are not yet ready for — or not suitable for — knee replacement surgery, genicular artery embolization offers something genuinely new. It is a minimally invasive interventional radiology procedure that targets the abnormal blood vessels driving synovial inflammation in the arthritic knee, reducing pain without surgery, without general anaesthesia, and without the prolonged recovery that joint replacement demands.
Understanding exactly how this procedure works — from the moment the patient arrives to the mechanism by which it relieves pain — helps patients and referring clinicians make informed decisions about whether it is the right option. At Alnoor Diagnostic Centre in Shadman, Lahore, our interventional radiology team performs genicular artery embolization with precision imaging guidance and a patient-centred approach to care.
Why Abnormal Blood Vessels Are Central to Knee Pain
Before understanding how the procedure works, it helps to understand the biological problem it addresses. In a healthy knee, the synovial membrane — the lining of the joint — has a modest, well-regulated blood supply that supports its normal functions. In osteoarthritis, chronic synovial inflammation triggers the formation of abnormal new blood vessels within the synovium — a process called neovascularisation. These vessels are structurally abnormal, leaky, and accompanied by nerve fibres that transmit pain signals.
This abnormal vascular network feeds and sustains the inflammatory environment inside the joint, perpetuating the cycle of synovitis, cartilage degradation, and pain. The more abnormal vessels present, the more active the inflammation and the more severe the pain. Genicular artery embolization works by selectively blocking the blood supply to these abnormal vessels, reducing the inflammatory activity they sustain and thereby reducing pain.
Step One — Patient Assessment and Imaging Review
The procedure begins well before the patient enters the procedure room. Careful patient selection is essential — not every patient with knee osteoarthritis is an appropriate candidate. The ideal candidate has moderate to severe knee pain from osteoarthritis that has not responded adequately to physiotherapy, oral medication, and joint injections, but whose joint damage is not yet at the stage requiring replacement.
Pre-procedure imaging review is mandatory. MRI of the knee confirms the presence of active synovial inflammation and assesses the degree of cartilage and structural damage. The interventional radiologist reviews this imaging alongside the clinical history to confirm that the pain pattern is consistent with inflammatory synovitis rather than primarily mechanical joint failure, which would not respond to embolization.
Step Two — Arterial Access Under Local Anaesthesia
On the day of the procedure, the patient is positioned on the angiography table and the skin over the access site — typically the femoral artery in the groin or the popliteal artery behind the knee — is cleaned and draped. Local anaesthetic is injected into the skin and underlying tissue. This is the only injection the patient feels — the procedure itself is performed entirely under local anaesthesia with mild sedation if needed, requiring no general anaesthetic.
A small needle is inserted into the artery under ultrasound guidance, and a short plastic tube called a sheath is placed through which all subsequent instruments pass. The arterial puncture site is tiny — just a few millimetres — and requires no surgical incision.
Step Three — Angiography to Map the Blood Vessels
Once arterial access is established, a thin flexible catheter is advanced through the sheath into the arterial system. The interventional radiologist uses fluoroscopy — real-time X-ray imaging — to guide the catheter through the arterial tree toward the genicular arteries — the network of blood vessels supplying the knee joint.
Contrast dye is injected through the catheter and fluoroscopy shows the blood vessels filling in real time — a technique called angiography. This produces a detailed roadmap of the arterial anatomy around the knee, identifying which vessels are normal and which show the characteristic pattern of abnormal neovascularisation associated with inflammatory synovitis — typically appearing as dense, irregular blushes of contrast in the synovial tissue rather than the clean, defined vessels of normal anatomy.
This angiographic mapping is critical. It tells the radiologist exactly which vessels are feeding the abnormal synovial tissue and therefore which specific vessels need to be embolized. Treating the wrong vessels achieves nothing and risks complications. Treating the right vessels with precision is what makes the procedure effective.
Step Four — Selective Catheterisation of Target Vessels
Once the target vessels are identified, the radiologist advances a microcatheter — an extraordinarily fine catheter just a fraction of a millimetre in diameter — through the larger catheter and selectively positions it within the specific abnormal vessel to be treated. This microcatheter navigation requires considerable skill, as the genicular arteries are small and the target vessels feeding the synovium are even smaller branches arising from them.
The position of the microcatheter tip is confirmed on fluoroscopy before any embolic material is delivered — a critical safety step ensuring treatment is delivered precisely where intended.
Step Five — Embolization
With the microcatheter positioned correctly, tiny embolic particles — microspheres approximately 75 to 200 micrometres in diameter — are injected through the catheter directly into the target vessels. These microspheres lodge within the small abnormal vessels, physically blocking blood flow to the inflamed synovial tissue they supply.
The embolization endpoint is confirmed angiographically — contrast injection after particle delivery shows reduced or absent flow in the treated vessels while normal vessels in the surrounding tissue remain unaffected. The radiologist embolizes each abnormal vessel systematically, working through all the identified target vessels on the affected side of the knee — typically treating the medial, lateral, and sometimes superior genicular arteries depending on which show abnormal neovascularisation.
Step Six — Procedure Completion and Recovery
Once all target vessels have been treated and the angiographic result is confirmed, the catheters are removed and the arterial access site is closed with gentle manual pressure or a closure device. No surgical stitches are required. The patient is moved to the recovery area and monitored for one to two hours.
Most patients experience mild aching around the knee in the first 24 to 48 hours as the treated tissue responds to the reduction in blood supply. This is expected and managed with simple oral pain relief. Patients are typically discharged the same day or the following morning and can walk immediately, resuming light normal activities within a few days.
Pain relief from genicular artery embolization typically develops gradually over two to eight weeks as the inflammatory activity in the synovium reduces following the interruption of its abnormal blood supply. Clinical studies show meaningful pain reduction in the majority of appropriately selected patients, with benefits persisting for one to three years in many cases.