A lady of 57 yrs had complained of pain knee jts, treated for Osteoarthritis with SYSDOA, analgesics and Physical Therapy. For last 3 months, she has hypertrophy of calf muscles and hamstring leading to mechanical restriction of knee flexion.

Muscle tone raised, body weight 84 kg, non-diabetic, euthyroid, non-hypertensive. What could be the probable management?