We present a rare case of delayed femoral nerve palsy resulting from a pseudo-aneurysm presenting as excruciating anterior thigh pain 2 months after an uneventful total hip arthroplasty through a Watson Jones approach. The large pseudo-aneurysm of the posterior wall of the femoral artery was treated with open exploration and artery repair since the anatomy of the lesion precluded an embolization. Although pain resolved immediately, the recovery of the femoral nerve started after 3 months, while full quadriceps function was restored by the 6th month. Positioning a Hohmann retractor along the inferior part of the anterior acetabulum rim may place the femoral artery branches under significant stretch. Preserving the capsule and keeping the retractor tension as low as possible may avoid this complication.