Degenerative joint disease of the lower limbs and degenerative lumbar stenosis are commonly seen in the elderly population. Although hip arthroplasty is routinely performed, it is not without complications. We present a case of a 64-year-old lady with arthritic hip pain and asymptomatic lumbar spine stenosis. This patient underwent a primary total hip replacement for hip arthritis and developed an ipsilateral foot drop one day after surgery. A hip MRI showed likely sciatic nerve impingement over a tense capsule. Despite revision surgery, the foot drop persisted. Nerve conduction studies and a lumbosacral MRI revealed spinal canal stenosis at L4/5. When nerve palsies such as a foot drop occur after hip arthroplasty, spinal stenosis must be considered as part of differential diagnosis and should be radiologically excluded before performing exploratory surgery.