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ULTRASOUND-GUIDED TREATMENT OF CHRONIC KNEE PAIN DUE
TO OSTEOARTHRITIS: DIAGNOSTIC AND THERAPEUTIC APPROACH
BASED ON THE TYPE OF PAIN
Maykon Hayak Pereira Lopes1
Abstract: Knee osteoarthritis (OA) is a prevalent cause of chronic pain and disability. Pain phenotyping
(inammatory, mechanical, and neuropathic) guides more effective interventions. Ultrasound (USG)
allows diagnostic stratication (synovitis, effusion, periarticular changes) and accurately guides
intra-articular injections (corticosteroid, local anesthetic, hyaluronic acid), genicular nerve blocks,
and Valeix injections. This review summarizes the diagnostic basis, technique, and pharmacological
choices guided by USG, discussing evidence and practical applications.
Keywords: osteoarthritis; knee; ultrasonography; genicular block; joint injection; chronic pain.
1 Anesthesiologist certied by the Brazilian Society of Anesthesiology, he graduated in Medi-
cine from the University Center of Espírito Santo (UNESC) and completed a Medical Residency in
Anesthesiology. He also works as a Medical Residency Professor in Anesthesiology at HMSJ.
Introduction
Osteoarthritis (OA) of the knee is the most common joint disease and one of the leading
causes of disability after age 50. (Hunter DJ et al, 2019)
Pain in OA results from the interaction of inammatory, mechanical, and neuropathic
mechanisms; Identifying the predominant mechanism improves therapeutic selection. (Bannuru RR
et al, 2019)
Ultrasonography (USG) has been consolidated in interventional practice because it combines
dynamic evaluation and real-time guidance of the needle, with greater accuracy and safety of the
procedures. (Finlayson RJ et al, 2012)
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Diagnosis and differentiation of pain types
Chemical/inammatory pain: mediated by cytokines (IL-1, TNF-α) and prostaglandins;
clinically it progresses with morning stiffness and pain at rest; USG shows synovial thickening,
effusion, and Doppler hyperemia. (Hunter DJ et al, 2019)
Physical/mechanical pain: related to structural overload due to chondral degeneration,
osteophytes, and subchondral bone alterations; it manifests with pain on exertion and relief at rest;
US may show effusions, chondral irregularity, and osteophytes. (Bannuru RR et al, 2019)
Neurological/neuropathic pain: involves peripheral and central sensitization; it is characterized
by burning, shocks, allodynia and hyperalgesia; DN4 and PainDETECT instruments aid clinical
screening. (Freynhagen R et al, 2006)
USG-guided therapeutic strategies
Inammatory (chemical) pain
USG-guided intra-articular inltration with corticosteroids (triamcinolone or
methylprednisolone), with or without local anesthetic, rapidly reduces synovial inammation with
short-term benets. (Bannuru RR et al, 2019)
Viscosupplementation with hyaluronic acid (HA) can be added when there is persistence
of inammatory pain or coexistence of mechanical pain; formulations with higher molecular weight
have greater persistence of effect. (Jevsevar DS et al, 2013)
Physical/mechanical pain
In predominantly mechanical pain, HA reduces joint friction and improves function in the
medium term. (Jevsevar DS, 2013)
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Platelet-rich plasma (PRP) shows expanding evidence for improvement in pain and function
in knee OA, with results superior to HA in some studies. (Filardo G et al, 2015)
Neurological/neuropathic pain
USG-guided genicular nerve block (GNB), directed at the superomedial, superolateral, and
inferomedial branches, is indicated when there is peripheral hypersensitization or refractoriness to
intra-articular inltration. (El-Hakeim EH et al, 2018)
Local anesthetics, corticosteroids, or 5–10% glucose solution may be used for perineural
neuromodulation, depending on the clinical phenotype and previous response. El-Hakeim EH et al,
2018)
Valeix suture inltrations (PIT) focus on periarticular sensory branches that are painful to
palpation and may employ local anesthetic or hyperosmolar glucose. (Jevsevar DS, 2013)
Role of Ultrasonography (USG): Accuracy, Safety, and Personalization
USG enables real-time guidance (in-plane and out-of-plane planes), needle tip visualization
and solution spreading, and the use of hydrodissection to open tissue planes, increasing the hit rate
and reducing failures. (Finlayson RJ et al, 2012)
Color Doppler maps genicular and periarticular vessels prior to puncture, mitigating
intravascular injection and hematomas—especially useful in genicular blocks and periarticular
inltrations. (Finlayson RJ et al, 2012)
Compared to uoroscopy, ultrasound eliminates radiation, is portable, enables outpatient
procedures, allows dynamic evaluation and longitudinal documentation (e.g., post-inltration stroke
reduction) without patient displacement. (Valeix B et al, 1948)
Good practices include transducer and puncture plane selection, ne echogenic needles (22–
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25G), conservative volumes with intermittent aspiration, and imaging/video recording. Prociency
requires structured training and a supervised learning curve. (Valeix B et al, 1948)
Chart 1 – USG-guided management of chronic knee pain due to osteoarthritis
Type of pain Clinical features USG ndings USG-guided interventions Usual drugs Evidence
Chemical /
Inammatory
Pain at rest,
morning stiffness,
improvement with
NSAIDs
Synovitis, effusion,
Doppler hyperaemia
Intra-articular inltration Corticosteroids
± local
anesthetics; OH
Forte (OARSI/
ACR)
Physics /
Mechanics
Pain on exertion,
worsening on stairs,
relief on rest
Osteophytes, chondral
irregularity, meniscopathy
Viscosupplementation;
PRP/Prolotherapy
OH; PRP Moderate–
strong (HA/
PRP)
Neurological /
Neuropathic
Burning, shock,
a l l o d y n i a ,
hyperalgesia
low-specic USG; Lock
Test
GNB; PIT (Valeix) L A ,
corticosteroid,
glucose 5–10%
M o d e r a t e
(GNB RCT;
PIT series)
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Figure 1 – USG-guided diagnostic-therapeutic algorithm for knee OA
Discussion
Stratifying pain by mechanism guides choices: intra-articular inltration (corticosteroid/
HA) for inammatory and mechanical pain; GNB and ITP for refractory neuropathic component.
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(El-Hakeim EH et al, 2018)
Therapeutic combinations (e.g., HA for mechanics associated with GNB for neuropathic
pain) and non-pharmacological measures (exercise, weight loss, physiotherapy) enhance clinical
outcomes. (Bannuru RR et al, 2019)
Limitations include methodological heterogeneity, technical variations, and lack of
standardization of volumes/drugs and outcomes—requiring better quality comparative studies. (El-
Hakeim EH et al, 2018)
Conclusion
The management of chronic pain in knee OA should be individualized according to the
predominant mechanism of pain.
USG is a central tool because it integrates diagnostic evaluation, precise needle guidance,
and response monitoring, increasing safety and efcacy. (Finlayson RJ et al, 2012)
Under USG, inltrations with corticosteroids and HA, PRP, prolotherapy, GNB, and ITP
make up a versatile arsenal; Selection should be guided by pain phenotyping and functional goals.
(Filardo G et al, 2015)
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