Background: Hypertrophic nonunion after intramedullary (IM) nailing represents a failed self-organization of the fracture healing system. In the language of Wolfram’s principle of computational irreducibility, the coupled biological and mechanical cascade is a complex program whose exact trajectory cannot be shortcut. Experimental work in fracture mechanobiology, however, points to a shear-dominated interfragmentary environment as a major driver of this unpredictability. Objective: To formulate a unified framework that links mechanoregulatory physics, interfragmentary strain (IFS) mathematics, and a physics-informed AI planner, and to illustrate its clinical application in femoral hypertrophic nonunion and shear-prone fractures treated with a shear-shielding nail-plate construct. Methods: IFS was decomposed into axial (?x) and transverse (?y) components to quantify the “shear trap.” Building on stiffness superposition, we modeled how adding a short non-locking 3.5-mm lateral plate in parallel to an IM nail alters the local strain field. A physics-informed surrogate model, trained on a library of finite-element simulations, was conceptualized to predict ?x and ?y for candidate nail-plate constructs and to optimize plate length and position under constraints of osteogenic strain, cost, and implant availability. Four femoral cases were treated with an IM nail plus a short lateral buttress plate without nail exchange. Results: Theoretical modeling shows that nail-plate augmentation can move the construct from a shear-dominant regime (high ?y) toward an axial-favourable regime (preserved ?x with reduced ?y), consistent with mechanobiology favoring callus bridging. Clinically, three hypertrophic or shear-prone femoral cases achieved progressive consolidation after addition of a short lateral plate without nail exchange, with pain relief and functional recovery. In a fourth case, the same side-plating strategy was used to lock a corrected rotational alignment after symptomatic malrotation from IM nailing, with CT-confirmed restoration of near-symmetric femoral torsion. Conclusion: By using AI to operationalize vector mechanics and shear control, the shear-shielding nail-plate construct suppresses the stochastic noise of transverse shear while preserving axial load sharing. This framework offers a mechanistically rational, cost-conscious, and potentially generalizable strategy to tame computational irreducibility in hypertrophic nonunion and shear-prone fractures.