Patellofemoral pain syndrome, also known as skeletal tenderness syndrome, is clinically more common and is bilateral and seen in young people. It is caused by a bare fracture or excessive activity of the skeleton or femur, degeneration of the skeleton, or poor alignment of the skeleton. The clinical manifestations are pain and friction sounds on the posterior aspect of the skeleton, knee flexion, limited knee movement after prolonged sitting, and pain relief after a little activity. Occasionally, the knee joint is swollen, and there is pain on pressure on the patella and percussion on the inner edge of the patella. Knee x-ray can be used to understand the degenerative changes of the knee joint and the alignment of the skeleton. Knee arthroscopy may aid in the diagnosis. Conservative treatment for this sign includes internal NSAIDs, cold compresses, proper rest, avoiding excessive use of the knee joint, and strengthening quadriceps exercises. If non-surgical treatment is ineffective, surgical treatment is feasible, such as patellar tendon grafting, which can change the poor patellar axis; tibial tuberosity padding, which can reduce the pressure on the surface of the skeleton; patellar cartilage cutting is suitable for those with more severe patellar cartilage surface breakage.