γγN fossa cysts, also known as Baker’s cysts, generally occur in the medial head of the gastrocnemius muscle and are located posterior to the semimembranosus muscle flap of the gastrocnemius muscle often communicating with the posterior joint capsule N fossa cysts are mostly caused by chronic injuries to the knee joint such as posterior meniscal horn injuries, while the onset in the elderly is mostly associated with knee pathology and proliferative arthritis mostly seen in middle age or older with limited pain in knee extension or flexion. Patient complaints are often characterized by gradual swelling of the N-fossa area. Occasionally, the enlarged capsule can compress and obstruct venous return causing calf edema.γγIn the past, N-fossa cysts were routinely removed via the posterior knee joint, and the incision required 10-20 cm, with long postoperative walking time and large scars, even affecting walking. Now we use arthroscopic minimally invasive treatment for N-fossa cysts, which only requires 3-4 small incisions of about 0.5cm, and you can walk on the ground the day after surgery, with fast recovery, good efficacy and low recurrence rate.