Objective To investigate the therapeutic effect of arthroscopic selective debridement for geriatric knee osteoarthritis (OA). Methods Arthroscopic selective debridement was performed on 182 (206 knees) elderly patients with knee osteoarthritis aged over 60 years, 62 males and 120 females, with 86 cases of knee inversion and 15 cases of knee valgus. The main arthroscopic pathological changes were: patellar tilt, patellofemoral arthritis in 137 cases, medial synovial crease in 103 cases, medial intertrochanteric cartilage 3-4 degree damage in 73 cases, lateral intertrochanteric cartilage 3-4 degree damage in 13 cases, meniscal damage in 82 cases, and free body in 72 cases. In response to the above pathological changes, we chose to release the lateral support band, excise synovial folds, grind and shape the uneven articular cartilage, shape or excise the meniscus, and remove the free body, etc. Postoperatively, we focused on the function of the quadriceps muscle. Results After 6-12 months of postoperative follow-up, the patients felt good about themselves and had no pain in 43 cases (23.6%), had significantly improved symptoms and reduced pain in 87 cases (47.8%), had no improvement in symptoms in 42 cases (23.1%), and had slightly worsened pain symptoms in 10 cases (5.5%). Conclusion Arthroscopic selective and limited joint debridement is less invasive and faster in postoperative functional recovery, which can effectively relieve symptoms (71.4%), improve function and enhance the quality of life of elderly patients. Factors affecting the efficacy were mainly advanced age, inappropriate selection of surgical indications, severe joint degeneration, severe internal and external knee deformity, and postoperative functional recovery of the quadriceps muscle.