An external fixation frame for correcting a bone deformity includes a first fixation ring and a second fixation ring. A posterior adjustable length strut couples a posterior portion of the first fixation ring to a posterior portion of the second fixation ring and has universal joint. Medial and lateral adjustable length struts couples medial and lateral portions of the first fixation ring to medial and lateral portions of the second fixation ring respectively, each of the medial and lateral adjustable length struts including a constrained hinge joint. The fixation frame also includes a half ring hingedly coupled to the second fixation ring, and an anterior adjustable length strut coupling an anterior portion of the first fixation ring to the half ring.