Hello and welcome to HCM, Sciatica is characterized by pain which radiates from back of hip to side of thigh to front of leg and then to feet and toes. It is caused by compression of nerve in the lower back. A clinical assessment is required to diagnose the condition as sciatica. Sciatica is managed by physiotherapy and rest. The hard bony lump under the knee needs to be examined and its nature needs to be determined. The hard lump is probably bony in nature. A X-ray of the knee joint is required to assess the lump whether it is arising from bone. Bony growth can be a neoplastic lesion and its management depends on its nature, size and location. Thus, I suggest you to consult an orthopedician for clinical assessment and thus management. Thanks and take care Dr Shailja Puri