Several dysfunctions can produce a psoatic limp
- Legg-Calvé-Perthes Disease: 
The psoatic limp in LCP may be caused by weakness or reflex inhibition of the psoas major muscle. The affected legg moves in external rotation, flexion and adduction.
The limp may be accompanied by exaggerated trunk and pelvic movement.
- David J. Magee. Orthopedic physical assessment 5th ed. St Louis: Saunder Elsevier 2008; p 967