The presence of the posterior talar triangle was first described by Rosenmuller in 1840, with an overall incidence of 1.7-7%. Usually the posterior talar triangle does not cause symptoms such as pain. However, in sports such as soccer, gymnastics and dance, excessive plantarflexion can cause the posterior talar triangle to impinged between the posterior tibial labrum and the heel bone, resulting in painful discomfort that interferes with movement and is called a painful posterior talar triangle. The painful posterior talar triangle should be surgically removed if conservative treatment is not effective. Incisional surgery is usually performed using a posterior lateral incision of the Achilles tendon, but it is prone to damage the peroneal nerve, and the incidence can be as high as 19.5% [1]. From January 2002 to June 2007, 22 cases of posterior talocrural triangle bone were resected by the posterior ankle arthroscopic approach technique in our institute, and good results were achieved. 1. clinical data and methods 1.1 General data From January 2002 to October 2007, 22 cases of painful posterior talocrural triangle bone were resected arthroscopically at our institute using the posterior approach technique. A total of 21 cases were followed up for a mean of 33 months (8-75 months). 15 of the 21 patients were male and 6 were female, with a mean age of 23.7 years (13-47 years). 15 cases were athletes or dancers, including 7 cases of soccer, 2 cases of basketball, and 1 case each of gymnastics, diving, tennis, javelin, weightlifting, and dance. The time interval from the onset of symptoms to the consultation was 3 months to 2 years. Twelve of the 22 cases had a clear history of trauma, including 9 cases of post-spin injury and 3 cases of unspecified sprain; 9 cases had no clear history of trauma. All patients showed symptoms of posterior ankle pain, which was aggravated when performing sports such as running and jumping. Physical examination could produce significant pain by pressing at the posterior aspect of the ankle joint and both sides of the Achilles tendon toward the level of the posterior talus, and was positive for plantarflexion squeezing pain. All 22 cases in this group underwent a frontal and lateral X-ray examination of the ankle joint before surgery, and the lateral films showed a triangular or oval posterior talar triangle behind the talus. 11 cases had mild osteoarthrosis of the ankle joint. 8 cases underwent MRI examination before surgery and found edema signal in the posterior talar triangle and surrounding tissues, and the normal low signal fiber connection between the posterior talar triangle and the talus was interrupted and fluid signal appeared. 1.2 Surgical method, microscopic performance and postoperative rehabilitation All 21 patients underwent ankle arthroscopic surgery. The surgery was performed using intra-lumbar anesthesia with the patient in prone position and a tourniquet at the root of the affected thigh with a pressure of 300 mm Hg. A 30° diameter 4.0 mm arthroscope was used with a posterior-lateral (located 1.5 cm above the tip of the outer ankle and 0.5 cm lateral to the Achilles tendon) and a posterior-medial approach (located 1.5 cm above the tip of the outer ankle and 0.5 cm medial to the Achilles tendon) to the ankle joint. After the skin was cut with a small knife and the subcutaneous tissue was bluntly separated with a vascular clamp, the blunt-tipped trocar was first inserted through the posterior lateral approach in a vertical direction and at an angle of 15 degrees to the sagittal plane to place the arthroscope, and after the water entry was opened, the blunt-tipped trocar was then inserted through the posterior medial incision toward the arthroscope. After the blunt tip cannula was observed from the posterior lateral approach, the blunt tip was withdrawn, the planer was inserted, and the fatty tissue was cleared from the posterior medial approach to the posterior aspect of the ankle joint to expose the [long flexor tendon, after which the fatty tissue was further cleared lateral to the [long flexor tendon to reveal the posterior lip of the tibia and the posterior border of the heel bone. The posterior talar triangle can be found lateral to the [long flexor tendon, between the talus and the heel bone. The planer is used to remove the connection of the posterior talar triangle to the surrounding tissue, including part of the posterior talofibular ligament attached to it. If the posterior talar triangle is small and not tightly attached to the talus, it can be removed intact with free body grasping forceps; conversely, the posterior talar triangle is removed by crushing it with medullary forceps. During intraoperative plantarflexion microscopically, the posterior tibial rim and heel bone can be observed to extrude and impinged on the posterior talar triangle, and the impingement disappears after resection. If there was also [long flexor tendon tenosynovitis, the inflammatory tendon sheath could be removed with a planing knife, and care was taken to remove the bone tissue immediately outside the tendon to avoid entrapment of the tendon. Arthroscopically, the synovial membrane of the posterior aspect of the ankle joint was found to be inflamed to varying degrees in 21 cases, and eight cases were combined with [long flexor tendon tenosynovitis, and arthroscopic tendon release/tendon sheath resection was performed. Postoperatively, sterile dressings and thick cotton pads were applied to the affected ankle and calf for 3 days, and the elastic bandage was replaced. On the first postoperative day, the patient was able to go to the ground (partial weight-bearing on the affected side), and gradually progressed to full weight-bearing in 2-3 days. No cast immobilization is required. Ankle flexion and extension exercises (with emphasis on dorsiflexion exercises) were started in the first week after surgery, and normal daily activities could be resumed 2 weeks after surgery, and sports were started 4 to 6 weeks after surgery. 2. Results The preoperative and postoperative American Foot and Ankle Surgery (AOFAS) hindfoot scores, as well as subjective pain (VAS scale, 0 to 10 points) scores, were performed in 21 patients who obtained follow-up, and paired t-tests were performed separately. The preoperative AOFAS hindfoot score was 73.3±3.6 (34-75); postoperatively, 94.8±5.1 (90-100). The mean postoperative improvement of 21.5 points over the preoperative was statistically different.