Five patients with femoral-shaft fractures were treated by cast-brace application and early ambulation. As fracture healing progressed, pressures between the thigh and the cast were recorded with the patients lying still, contracting the quadriceps while lying down, and in four weight-bearing postures. Control results were gained by application of a second cast-brace to three of the patients when they had recovered completely. Resting pressures averaging sixteen millimeters of mercury were recorded under the whole cast. Much higher values were recorded under the proximal two-thirds of the cast, and these increased as healing proceeded. Removal of the hip hinge, thereby eliminating fixed abduction, reduced pressure recordings significantly.