tokens: These 20 patients had a total of 28 OCD lesions : 43 % ( 9 femur , 3 talus ) were radiographically stable over time , 50 % ( 10 femur , 2 patella , 2 talus ) were unstable at initial diagnosis , and 7 % ( 2 femur ) were initially stable but progressed to unstable lesions despite drilling .