Limb threatening arterial occlusion during total hip or knee arthroplasty is an uncommon complication. The authors present two cases of thrombosis of the common femoral artery that occurred following and during total hip arthroplasty respectively. Acute thrombectomy was performed in both patients within 3-4 hours after the diagnosis. Both patients permanently kept some numbness over the foot and slight weakness in the extensors. With a delayed diagnosis such lesion may have lead to the loss of their limb. This underlines the absolute need for regular control of the arterial supply, sensory and motor conditions following joint arthroplasty during the first 24 hours following surgery.