Orthopaedic device (10, 110, 210, 310) for correcting deformities of a long bone (11), comprising a bar (12), extended along an axis (Y-Y) and intended to be placed alongside the bone (11), at least a first clamp (14, 214, 314) for a first group of osseous screws (16) and a second clamp (18, 19, 118) for a second group of osseous screws (20, 22), removably mounted on said bar (12), wherein the first of said clamps (14, 214, 314) is placed onboard a support base (21, 221, 321) in turn mounted on said bar (12), and angularly movable in relation to the support base around a given rotation axis (X-X, X′-X′, Z-Z) by means of a rotary coupling, characterised in that said rotary coupling comprises a male element (35; 235, 236, 237, 238, 239; 333, 334) associated with the first clamp (14, 214, 314) and having a surface at least partially cylindrical, and a corresponding female element (36; 130; 250, 254, 255; 336, 337) associated with the support base (21, 221, 321) and having a surface at least partially cylindrical constituting a seat for the loose coupling of the male element (35; 235, 236, 237, 238, 239; 333, 334).