Osteoarthritis (OA) and rheumatoid arthritis (RA) have long been framed as degenerative and autoimmune entities, respectively; mounting evidence instead supports a unified mechano-immune paradigm in which joint loading and inflammatory signaling are reciprocally reinforcing. In this review, we synthesize advances across mechanotransduction (Piezo1; YAP/TAZ), focal-adhesion/cytoskeletal regulation (vinculin, filamin-A; upstream talin-1/Kindlin-2/paxillin), and niche inflammatory mediators (HE4, IL-36/IL-38) to explain how mechanical stress and cytokines co-produce persistent catabolism, synovial invasion, and fibrotic remodeling. We articulate a dual-hit model in which OA is predominantly mechanical-overload-driven, with secondary inflammation, whereas RA is immune-driven but imposes abnormal mechanical stress that further distorts joint biomechanics; both converge on canonical hubs (NF-κB/MAPK/JAK-STAT) to accelerate matrix degradation and apoptosis. Building on this framework, we propose integrated multi-marker panels that combine mechanosensors and adhesion proteins with conventional assays (CRP, ESR, anti-CCP) to enhance differential diagnosis and prognostication, particularly in postmenopausal women, where estrogen decline heightens mechano-immune susceptibility, thereby offering a means to quantify the impact of mechano-immune dysregulation. Integrating mechanotransductive and cytoskeletal biomarkers with conventional serological indices has been reported to improve differential diagnosis between osteoarthritis and rheumatoid arthritis in exploratory studies. While the magnitude of diagnostic gain varies across cohorts, combined biomarker strategies generally show enhanced discriminatory performance compared with single-marker approaches. These findings highlight translational potential but require validation in large, standardized clinical populations before routine implementation. Finally, we map translational opportunities spanning Piezo1 inhibition (GsMTx4), YAP/TAZ blockade (verteporfin), IL-36 axis antagonism (IL-36Ra, IL-38), anti-HE4 strategies for RA-ILD, and adhesion-stabilizing approaches, alongside mechanoresponsive biomaterials for regenerative applications and precision medicine guided by biomarker profiles. Collectively, this review reframes OA and RA as mechano-immune syndromes and delineates a clinically actionable roadmap from biophysics to bedside.