431: Sonographic Phenotyping & Protocol-Based Interventions in Knee Osteoarthritis - Retrospective Study

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Chronic primary musculoskeletal pain, Assessment and Measurement of Pain/Nociception, Treatment/management

Background and Aims: Knee osteoarthritis exhibits marked pathophysiological heterogeneity; yet interventional practice continues to apply uniform treatment algorithms irrespective of disease subtype, yielding inconsistent analgesic and functional outcomes.2 Sonographic phenotyping1 has emerged as a clinically accessible stratification tool capable of rationalising therapy selection at the point of care. We hypothesised that a standardised four-view musculoskeletal ultrasound protocol — capturing synovial, cartilage, biomechanical, and metabolic domains — could reliably classify patients into inflammatory, structural, or mixed phenotypes, and that phenotype-directed protocols would deliver superior outcomes.1,3 This study evaluates the clinical efficacy of a novel sonographic triage algorithm deploying cartilage-sparing lavage and oxidative modulation 4,5, orthobiologics6, and cooled neuromodulation7 according to the dominant phenotype.

Methods: A single-centre retrospective pilot review of 50 patients with knee osteoarthritis was conducted, A standardised four-view ultrasound protocol assessed suprapatellar synovial effusion, medial condylar cartilage thickness, medial joint line meniscal extrusion and osteophyte burden, and infrapatellar fat pad echotexture. Three phenotypic cohorts were identified and managed by protocol. Phenotype A (Inflammatory; N=17, 34%), characterised by predominant synovitis and fat pad heterogeneity with preserved cartilage, received intra-articular saline lavage followed by two sequential ultrasound-guided intra-articular ozone injections (10 mL, 40 µg/mL per session) administered ten days apart. Phenotype B (Structural; N=20, 40%) received regenerative therapy with or without cooled radiofrequency ablation (C-RFA) of the genicular nerves. Phenotype C (Mixed; N=13, 26%) underwent saline lavage with a single ozone session (10 mL, 40 µg/mL) to attenuate inflammatory synovial microenvironment, followed sequentially by regenerative therapy and C-RFA. Numeric Rating Scale (NRS), WOMAC scores recorded at baseline, one, three, and six months.

Results: All three phenotypic cohorts demonstrated statistically significant improvements from baseline (p < 0.05). Phenotype A (N=17) achieved rapid, sustained reductions in both resting and active NRS scores alongside progressive WOMAC improvement at one, three, and six months, confirming the anti-inflammatory and cartilage-sparing efficacy of the sequential lavage-ozone protocol. Phenotype B (N=20) exhibited a mean 62% improvement in WOMAC scores at six months, validating that structurally dominant disease responds optimally to regenerative therapy and genicular neuromodulation when active synovitis is absent. Phenotype C (N=13) achieved 58% sustained functional recovery at six months, demonstrating that prior attenuation of the inflammatory synovial microenvironment through lavage and ozone is essential to maximise the subsequent efficacy of regenerative therapy and C-RFA in complex mixed-phenotype disease.

Conclusions: Sonographic phenotyping successfully transitions knee osteoarthritis management from empirical, trial-and-error intervention to a precision medicine paradigm 1,2. Categorising patients into distinct inflammatory, structural, or mixed pathophysiological cohorts enables deployment of targeted, disease-modifying protocols with measurable functional outcomes. The lavage-ozone protocol for inflammatory phenotypes delivers robust, sustained analgesia while eliminating the chondrotoxic risk inherent to intra-articular corticosteroids. In mixed phenotypes, prior resolution of the inflammatory synovial microenvironment proves essential for maximising the efficacy of subsequent regenerative therapy and neuromodulation. This standardised four-view sonographic triage algorithm is reproducible within a high-volume interventional clinic and offers a scalable, evidence-aligned framework for phenotype-directed musculoskeletal pain management.

References: 1. Karalilova R, Popova V, Batalov K, et al. Ultrasound Phenotype-Based Approach to Treatment Choice in Osteoarthritis. Life. 2025;15(7):1140.

2. Dell'Isola A, Allan R, Smith SL, Marreiros SS, Steultjens M. Identification of clinical phenotypes in knee osteoarthritis: a systematic review of the literature. Osteoarthritis Cartilage. 2016;24(12):2136-2147.

3. Sarmanova A, Hall M, Moses J, et al. Synovial changes detected by ultrasound in people with knee osteoarthritis – a meta-analysis of observational studies. Osteoarthritis Cartilage. 2017;25(9):1383-1398.

4. Lopes de Jesus CC, Dos Santos FC, de Jesus LMOB, Monteiro I, Sant'Ana MSSC, Trevisani VFM. Comparison between intra-articular ozone and placebo in the treatment of knee osteoarthritis: A randomized, double-blinded, placebo-controlled study. PLoS One. 2017;12(7):e0179185.

5. Raeissadat SA, Rayegani SM, Forogh B, Hassan Abadi P, Moridnia M, Rahimi Dehgolan S. Ozone vs. Steroid Injection in Knee Osteoarthritis: A Randomized Clinical Trial. Pain Res Manag. 2018;2018:5340392.

6. Bennell KL, Paterson KL, Metcalf BR, et al. Intra-articular Platelet-Rich Plasma vs Corticosteroid Injections for Knee Osteoarthritis: A Systematic Review and Meta-analysis. JAMA Netw Open. 2021;4(12):e2137228.

7. Kapural L, Lee N, Neal K, Malyak M. Cooled radiofrequency ablation of genicular nerves for knee osteoarthritis pain: A review of current evidence. Pain Manag. 2019;9(6):579-588.

Presenting Author: SENTHIL PRAKASH MOHAN
Submitting Author: SENTHIL PRAKASH MOHAN

Senior Author: SENTHIL PRAKASH MOHAN

IASP 2026 Global Year theme of Neuropathic Pain: No

• SHAJITHA BEGUM NAINA: MBBS, DNB - RESILIO THE PAIN CLINIC