A 45-year-old male presents with progressive left knee pain and varus deformity. An AP weight-bearing radiograph of the knee is obtained. The structure marked **C** (intercondylar notch and tibial spines) is examined. Which of the following radiographic findings in the medial compartment would be MOST consistent with primary osteoarthritis of the knee, and what would be the expected appearance at the intercondylar region?