Reframing Obesity in Knee Osteoarthritis: A Call for a Transdisciplinary Approach Beyond Biomechanics.

The editorial commentary by LaPrade and colleagues1 provides an insightful overview of the limitations and clinical relevance of the study by Lin et al.2 which explores arthroplasty conversion rates in patients with obesity and osteoarthritis (OA) following knee arthroscopy. Obesity should not be considered solely a mechanical risk factor due to increased joint loading. It is increasingly recognized as a complex chronic inflammatory disease characterized by the dysregulated secretion of adipokines such as leptin, resistin, and adiponectin. These molecules are secreted by adipose tissue and exert systemic and local effects on joint tissues, particularly through the activation of pro-inflammatory pathways and matrix-degrading enzymes within the synovium and cartilage.3 Adiponectin, though classically associated with anti-inflammatory effects in other metabolic conditions, paradoxically exhibits pro-inflammatory behavior within osteoarthritic joints, stimulating nitric oxide and matrix metalloproteinase production in chondrocytes and synoviocytes.4 The study and commentary rightly highlight the limitations of current arthroscopic indications in patients with pre-existing OA and obesity. However, they overlook the potential impact of obesity-induced inflammation on the intra-articular environment, independent of mechanical stress. For instance, chronic systemic inflammation and local cytokine expression—mediated in part by adipokines—can alter the synovial fluid milieu and accelerate cartilage degradation even in the absence of overt biomechanical injury.5 In this light, arthroscopy, particularly when it includes procedures aimed at modifying the intra-articular environment, could play a disease-modifying role by interrupting the cascade of local inflammation. Indeed, this systemic-intra-articular connection may explain why, in select cases, minimally invasive procedures like arthroscopy are associated with temporary disease stabilization or delayed progression to arthroplasty, as the editorial notes. Orthopedic surgeons, as suggested metaphorically, may need to “extend their left hand to their colleague, the biologist” and temporarily “set aside the scalpel” to embrace adjunctive strategies aimed at modulating intra-articular inflammation, such as intra-articular biologics, anti-cytokine therapies, or systemic metabolic interventions. Moreover, a modern diagnostic algorithm for knee OA should be both clinical and laboratory-based, incorporating serum and synovial biomarkers of inflammation and cartilage metabolism. For instance, studies have shown that elevated levels of interleukin-6, tumor necrosis factor-alpha, and C-reactive protein are associated with both structural progression of OA and worsening patient-reported outcomes.6 This biomarker-guided approach could aid in identifying patients with “metabolic OA,” where systemic inflammation, rather than solely joint biomechanics, is the principal driver of disease.7 The commentary by LaPrade et al. opens an important door by reaffirming the nuanced outcomes of arthroscopy in OA patients, but the future of joint preservation lies in understanding the joint as an organ system embedded within a broader inflammatory and metabolic network. A shift toward a multidisciplinary, personalized medicine approach, integrating orthopedic surgery, immunology, and metabolic medicine, is not only justified but essential. In summary, obesity is more than a mechanical burden on the knee; it is a systemic disease with profound inflammatory consequences on joint health. Recognizing and addressing this broader pathophysiological landscape will enable clinicians to refine surgical indications, personalize treatments, and ultimately improve long-term outcomes in patients with knee OA. The authors (F.P., M.T.D.L., G.G.C., S.B., E.L.G., R.S., A.R.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.