A 65-year-old male complains of pain rt hip joint & rt calf muscle on standing & walking fot the past 4 months. Initially, relieved after physiotherapy and oral pregabalin 75 mg twice daily but reappeared after one month. Unable to walk for more than few steps. All biochemical tests normal exept TSH 9.5.

MRI of lumbar spine report attached. What could be the differential diagnosis? How to manage further?