Total Knee Replacement (TKR) is one of the most successful surgeries in modern-day orthopedics, performed mainly to treat end-stage knee osteoarthritis (OA) . degenerative spondylolisthesis is one of the most common causes of low back pain where a spinal vertebra slides from its anatomical position, affecting about 11.5% of the population, furthermore, many elderly patients undergoing TKR usually suffer from spondylolisthesis.~Spondylolisthesis with subsequent lumbar spine degenerative disease presents as lower back and radiating pain to the legs at rest or during activity, Spondylolisthesis causes hamstring tightness which is felt as pain at the back of the knee, lumbar radiculopathy of the L3 root nerve could vary from thigh pain to hip and/or knee pain, all of which could be misled as pain due to knee OA . On the other hand, patients having knee OA with a flexion deformity compensate their posture by increasing the lumbar lordosis, if the lumbar spine lost its ability to compensate for the knee deformity, this could aggravate low back pain and enhance further lumbar spine instability and spondylosis .~In addition, the persistence of coexisting lumbar spine symptoms after TKA might adversely affect postoperative outcomes in terms of pain and function, even after successful TKA .~Chang et al., studied the prevalence and severity of coexisting lumbar spondylosis in terms of radiographic lumbar spine degeneration and lumbar spine symptoms in patients with advanced knee OA undergoing TKR, in their study, 51% of patients undergoing TKR had at least one moderate to severe lumbar spine symptom, and patients with severe radicular pain on the activity before the TKR was likely to demonstrate poor knee function 2 years post-TKR . This is why lumbar spine pathologies should be fully investigated in patients coming for TKR.
This study aims to detect the incidence of spondylolisthesis in patients candidate for Total knee replacement (TKR) and to investigate the effect of TKR on the course of low back pain.