1, Data and Methods 1.1 General information In this group, there were 20 cases, 15 males and 5 females; age 11~50 years old, average 25 years old. All patients had a history of trauma, and the duration of the disease ranged from 6 months to 5 years after the injury. Mechanism of injury: 12 cases of internal rotation injury (60%); 3 cases of external rotation injury (15%); 3 cases of posterior rotation injury (15%), 2 cases of anterior rotation injury (10%), and the post-injury X-ray films were normal. They were treated with analgesia, local physical therapy and braking. Clinical manifestations: regardless of the length of time after the injury, they all showed ankle pain, swelling, ankle joint activity restriction of varying degrees, obvious recurrence and aggravation after activity. Preoperative diagnosis: ankle tuberculosis 7 cases, exfoliative osteochondritis 5 cases, chronic synovitis 5 cases, ankle soft tissue impingement syndrome 3 cases. 1.2 Treatment process Preoperative routine examination of ankle joint X-ray film, MRI, joint fluid routine, joint fluid culture + drug sensitivity. Before surgery, potassium permanganate diluted foot soak was used for 20 minutes twice a day to treat foot disorders such as tinea pedis. Hard lumbar joint anesthesia was used, tourniquet was applied to the root of the thigh, routine disinfection and laying of towels, the distal dorsum of the foot was continuously retracted with a homemade retractor belt, saline was injected into the joint cavity to dilate the joint cavity, and then a 5mm small incision was made in the ankle plane on the medial aspect of the anterior tibialis muscle (anterior-inferior) and on the lateral aspect of the extensor digitorum superficialis muscle (anterior-lateral), and small posterior-internal and posterior-external incisions were added according to the need. The skin is incised and subcutaneously separated bluntly with a small striker’s forceps to reach the joint cavity, until water overflows, taking care to avoid injury to the saphenous vein and the anterior tibial vascular nerve. An arthroscopic system was inserted to sequentially explore the various chambers, and a planer was used to excise the proliferated synovial membrane, and a biopsy forceps combined with a planer was used to remove the articular surfaces that were combined with cartilage destruction. Patients with cartilage denudation were drilled with a 1.5-mm grafting needle. Postoperative histopathological examination was given, and the affected limb was treated with elastic bandage and short leg plaster, anti-inflammatory and other symptomatic treatments. For patients with tuberculosis of the joint, anti-tuberculosis treatment was routinely given before and after the operation, and plaster fixation was given after the operation, so as to make the ankle joint fused in the functional position. Percutaneous hollow screw internal fixation was used when necessary. 2.Results The arthroscopic diagnosis was basically consistent with the preoperative diagnosis. Of the 3 cases of ankle soft tissue impingement syndrome, 2 cases were anterolateral and 1 case was posterior. The operation time was 90-120 min. all patients were followed up for 3 months to 2.5 years. After surgery, the patients’ pain disappeared, swelling subsided, and the rest of the joints had good mobility except for the joint tuberculosis for ankle fusion. 3.Discussion 3.1 Ankle arthroscopy access The ankle joint is a stable weight-bearing joint with a relatively narrow joint space. It is composed of lower tibiofibula and talus, and there are many important tendons and neurovascular structures around the joint: anteriorly, there are saphenous vein, tibialis anterior tendon, first phalanx tendon, dorsalis pedis artery, deep peroneal nerve, tendon of extensor digitorum communis, superficial peroneal nerve, and peroneal longus tendon; posteriorly, there are posterior tibialis posterior tendon, flexor digitorum longus tendon, flexor digitorum posterior tibialis tendon, posterior tibial artery and nerve, tendon of first phalanx longus, Achilles tendon, lesser saphenous vein, and peroneal shortus tendon. tendon, Achilles tendon, saphenous vein and short peroneal tendon. The common approaches used in ankle arthroscopy are anteromedial and anterolateral approaches, i.e., medial anterior tibialis muscle and lateral peroneus longus muscle in the ankle joint line. Although there is a risk of injury to the medial saphenous vein, saphenous nerve, and lateral superficial peroneal nerve in this approach, only the skin is incised in the operation, and subcutaneous to the articular cavity is bluntly separated by small striated clamps, so that the vascular and neurological injuries in this area can be avoided. The anteromedial and anterolateral approaches are convenient for revealing the ankle point and the anterior part of the talus, but there are limitations in revealing the posterior compartment and operation, and the addition of the posterolateral and trans-Achilles tendon approaches not only facilitates the revealing of the posterior compartment of the ankle joint. 3.2 Indications for ankle arthroscopy Diagnostic indications: unexplained ankle pain, swelling; interlocking; recurrent instability (habitual ankle sprains); persistent effusion; stiffness; impingement; biopsy. Therapeutic indications: free body removal; lavage for infected arthritis; synovectomy; treatment of degenerative arthritis; arthroscopic joint fusion; treatment of bone and soft tissue impingement; treatment of osteochondral lesions; treatment of recurrent joint instability; adjunctive fracture repositioning or fixation. Contraindications: systemic or local infection, limb ischemia, severe osteoarthritis with joint space narrowing, severe ankle edema, venous insufficiency, poor skin conditions, severe ankle trauma with fascial gap syndrome, reflex sympathetic atrophy. 3.3 Ankle arthroscopy surgical operation and points of attention In all ankle joint diseases, since ordinary X-ray cannot show the soft tissue lesions of the ankle joint, and CT and MRI examination can only indirectly reflect the lesions, arthroscopy can not only clearly observe the nature of intra-articular lesions and the exact location and scope of the lesions, but also carry out effective and targeted treatment. Preoperative joint fluid examination not only helps preoperative diagnosis, but also guides postoperative medication. Soft tissue lesions such as soft tissue impingement syndrome and chronic synovitis without articular cartilage damage can be treated microscopically without special treatment, and good results can be obtained by removing the hyperplastic and embedded chronic inflammatory synovial tissue. The postoperative scores of the cases with soft tissue lesions in the follow-up were excellent, and the subjective efficacy evaluations of the patients after the operation were all very satisfactory, and the resumption of daily life and sports was significantly earlier than that of the other lesions. For osteochondral lesions of the ankle joint, subchondral bone drilling or microfracture treatment should be performed in conjunction with lesion removal, except for infectious lesions such as tuberculosis. For osteochondral lesions, due to the presence of the lesion itself, the slower postoperative recovery and long-term efficacy need to be further tested and communicated to the patient. Tuberculosis of the joint leads to the loss of the entire layer of articular cartilage, and fusion of the joint cannot be avoided, so the ankle joint needs to be fixed in a functional position by internal fixation with screws or external fixation with a plaster cast. Ankle arthroscopy is associated with complications such as nerve injury, tendon and ligament injury, infection, and instrument breakage, so the operation should be performed carefully, with care for the tissues, and the surgical skills should be improved continuously.