[Objective] To summarize the clinical and pathological characteristics of ankle soft tissue impingement syndrome (ASTIS) and the effect of arthroscopic surgical treatment. [Methods] From November 2000 to April 2005, 21 cases of ASTIS were admitted and underwent arthroscopic surgery 13.6±9.9 months after injury, with microscopic removal of impingement tissue and pathological examination. The mean postoperative follow-up was 34.3 (7-60) months, and the surgical results were evaluated using the AOFAS (American Foot and Ankle Surgery Society) hindfoot-ankle score. [Results] Twenty cases occurred after ankle sprains, with the majority of inversion injuries (76.2%, 16/21); one case was secondary to osteoarthritis. There were 9 cases (42.9%) of anterolateral impingement alone, 2 cases (9.5%) of medial impingement alone, 1 case (4.8%) of combined lateral and anterolateral impingement, and 9 cases (42.9%) of both medial and anterolateral impingement. Arthroscopy revealed the presence of synovial impingement in 20 cases, followed by the distal bundle of the inferior anterior tibiofibular ligament in 5 cases, fibrous scar tissue in 4 cases, anterior talofibular ligament tissue in 3 cases, and meniscus-like tissue in 3 cases. 16 cases had combined articular cartilage damage. the objective and subjective scores of the AOFAS were significantly higher after surgery than before (overall score 67±9.7 preoperatively, 94±6.4 postoperatively, t=-7.205, P< 0.0001; subjective scores were 20.7±6.6 preoperatively and 35.7±4.9 postoperatively, t=-5.003, P<0.001). [Conclusion] Soft tissue impingement syndrome of the ankle joint is mostly secondary to ankle trauma. The site of occurrence was more common in the anterolateral aspect of the ankle joint. The impinging tissues were synovial, ligamentous, scar tissue and meniscus-like tissue. Arthroscopic treatment of soft tissue impingement syndrome of the ankle is satisfactory. Arthroscopic Treatment of Ankle Soft Tissue Impingement Syndrome JIAO Chen HU Yuelin The Institute of Sports Medicine, The Third Hospital of Peking University (100083) [Objective] To study the clinical characteristics and to assess the efficacy of arthroscopy in treatment of ankle soft tissue [Material and Method] From November, 2000 to April, 2005 21 patients with ASTIS were treated with From November, 2000 to April, 2005 21 patients with ASTIS were treated with arthroscopy to remove the impingement soft tissues 13.6±9.9 months after injury and the efficacy of arthroscopy was statistically assessed with AOFAS scoring system . [Result] Twenty of twenty one patients had history of ankle sprain which most were inversion injury. Anterolateral impingement occurred in nine Anteromedial impingement occurred in two. Lateral and anterolateral impingement simultaneously existed in one patient. Synovium was the most common impingement tissue followed by distal fascicle of anterior Synovium was the most common impingement tissue followed by distal fascicle of anterior tibiofibular ligament, fibrous scar, anterior talofibular ligament and meniscoid tissue. Sixteen patients had impingement syndrome combined with cartilage injury. AOFAS subjective and total score significantly improved postoperatively. [Conclusion] Ankle soft tissue impingement syndrome It occurs more in anterolateral side of ankle. Impingement tissues were synovium, distal Impingement tissues were synovium, distal fascicle of anterior tibiofibular ligament, fibrous scar, anterior talofibular ligament or meniscoid tissue. The result of arthroscopy in treatment of ankle soft tissue impingement syndrome is satisfactory. It is a condition in which the soft tissues of the ankle joint become embedded and rub together, causing pain, swelling, interlocking and restricted movement. It can occur as a result of altered joint forces or as a result of altered joint forces. It is usually associated with trauma to the ankle joint and can also be caused by synovial disorders. MRI is the main imaging basis for preoperative diagnosis of the disease, and arthroscopic resection of the impinging tissue is the main treatment measure. We retrospectively analyzed 21 cases of soft tissue impingement syndrome of the ankle joint admitted from November 2000 to April 2005, analyzed their etiology, arthroscopic manifestations and pathological characteristics, and evaluated the surgical results by follow-up. 1 , Clinical data and methods 1.1 General data The 21 cases in this group were 16 males and 5 females. The age ranged from 13 to 47 (24.7±6.5) years. There were 7 cases of athletes (3 cases of soccer, 1 case each of basketball, baseball, swimming and sports dance) and 14 cases of non-athletes. There were 9 cases of left ankle and 12 cases of right ankle. The time between onset and surgery ranged from 1 to 48 (13.6±9.9) months. 20 cases had a history of ankle sprain, including 16 cases of internal derangement (76.2%, 16/21), 1 case of external derangement, and 3 cases with unknown trauma mechanism; 1 case was secondary to osteoarthritis. The clinical manifestations all had ankle swelling and pain, which were aggravated after exercise, and 10 cases had deep squatting pain. On examination, the joint swelling was found in 9 cases; the pressure pain in the confined joint space (impact site) was positive; all cases had dorsal extension crushing pain, 6 cases had dorsal extension limitation of the ankle joint, 4 cases had both dorsal extension and plantar flexion limitation, and the mobility of the remaining 11 cases was normal. Preoperative X-ray examination was performed in all cases. 1 case of ankle avulsion fracture, 5 cases of ankle osteoarthrosis (1 case combined with medial heel talar bridge, 1 case combined with intra-articular free body), and the remaining 15 cases had no significant abnormalities. 14 cases of preoperative MRI examination suggested 6 cases (43%) of soft tissue embedded in the ankle joint, 1 case of uneven medial cartilage surface of the talus, 1 case of osteochondral exfoliation of the medial talus, 2 cases of laxity of the heel fibular ligament, 1 case of ankle avulsion fracture, one case of joint effusion, and two cases with no significant abnormalities. Severe ankle osteoarthropathy, rheumatoid arthritis, acute ligament injury and severe instability of the old ankle joint were excluded from this study. 1.2 Surgical methods All performed ankle arthroscopic exploration and excision of soft tissues embedded in the ankle joint, lumbar anesthesia combined with epidural anesthesia, supine position, and self-made traction belt with bandages. A 2.7 mm diameter 30ºarthroscope was applied, and an anterior external incision was first made on the lateral side of the third peroneal tendon or extensor tendon, saline was injected to fill the joint cavity, the joint was carefully separated to the joint with mosquito forceps under the skin, the joint was explored, and an anterior internal incision was made on the medial edge of the anterior tibial tendon under arthroscopic irradiation to avoid injury to the saphenous vein, which was separated into the joint with mosquito forceps, and this approach was used to enter the operating instrument. Arthroscopic observation of the soft tissue embedded in the ankle joint and cartilage injury, medullary forceps were used to remove part of the embedded soft tissue (impingement tissue) for pathological examination, and the impingement tissue was removed with basket forceps or a planer. 1 case was cleaned up with an additional anterior external approach 1 cm in front of the fibular tip. 14 cases of cartilage injury were planed with a planer to remove the raised cartilage, and the edges were trimmed to neatness with medullary forceps or cartilage scrapers. In 2 cases, the cartilage injury of layer IV with an area of less than 2 cm2 was treated with microfracture, i.e., the bone surface was cleaned until the subchondral bone was completely exposed, and 3 mm diameter tapered microfractors were used to punch holes at 3 mm intervals, 3 mm deep, to cover the cartilage defect area. 2 cases combined with rupture of the anterior talofibular ligament were incised intraoperatively, 1 case of rupture of the ligament was located on the proximal fibular side of the body and was closed with end overlap sutures, and 1 case was ruptured at the fibular stop and underwent stop In one case, the ligament rupture was located on the side of the body near the fibula, and the sutures were overlapped at the ends. Intraoperative tourniquet time ranged from 40 to 100 (67.25±14.75) min, and no surgical complications occurred in all patients. 1.3 Study methods AOFAS (American Foot and Ankle Surgery Society) scores were used before and after surgery and paired t-tests and satisfaction rate surveys were done. 2, Results 2.1 Microscopic findings and impingement histopathology Ankle arthroscopy revealed anteroinferior impingement in 2 cases, anteroinferior impingement in 9 cases, anteroinferior and posteroinferior impingement in 9 cases, and anteroinferior and posteroinferior impingement in 1 case (Figures 1 to 4). There were 20 cases of synovial impingement (including 6 cases of simple synovial impingement); 4 cases of scar impingement (1 case of simple scar impingement and 3 cases of combined synovial impingement); 5 cases of impingement of the distal bundle of the inferior tibiofibular ligament, 3 cases of impingement of the fibers of the anterior talofibular ligament, and 3 cases of meniscus-like impingement were combined with synovial impingement. The pathology of synovial impingement was characterized by chronic inflammation of synovial tissue with small vessel hyperplasia. The pathological findings of scar tissue impingement were granulomatous tissue hyperplasia or dense connective tissue. The pathology of impingement of the distal bundle of the inferior tibiofibular ligament and the fibers of the anterior talofibular ligament both showed ligamentous tissue. The pathology of meniscus-like tissue impingement showed chronic synovitis or degenerative dense connective tissue with focal chondrogenesis, or chronic synovitis with granulation tissue formation. 2.2 Cartilage injuries Sixteen cases (76.2%, 16/21) had cartilage injuries of different degrees in the talotibial joint, including 11 cases of cartilage injuries in the talus, 3 cases of cartilage injuries in the tibia, and 2 cases of cartilage injuries on the opposite sides of the talotibial joint. The soft tissue impingement and cartilage injury occurred at the same site in 10 cases (47.6%), and the correlation between the two is represented by the correlation between the two, and the х2 test showed no significant correlation (х2=2.524, P=0.112). 2.4 Follow-up At 7-60 (34.3±9.4) months postoperative follow-up, the overall AOFAS score was 67±9.7 preoperatively and 94±6.4 postoperatively, with a significant difference (t=-7.205, P<0.0001). the subjective AOFAS score was 20.7±6.6 preoperatively and 35.7±4.9 postoperatively, with a significant improvement compared to the preoperative score (t=- 5.003, P<0.001). Only one case had an AOFAS score less than 85 (77) after surgery, and the subjective scores were not less than 30. The patient's satisfaction rate with the surgical results was 90% (19/21), and all the other 19 cases were close to or reached the pre-injury sports level except for two cases that were dissatisfied. Ankle sprain is the most common sports trauma, with an incidence of 30% in the general population and 40% in athletes. Trauma is an important cause of soft tissue impingement in the ankle joint. In our group, 95% (20/21) of soft tissue impingement syndromes of the ankle occurred after trauma, especially after internal derangement injuries. A few cases can also be secondary to non-traumatic disorders, such as joint infection, osteoarthritis, pigmented villous nodular synovitis, hemophilic synovitis and intra-articular tumors. One case in our group was secondary to ankle osteoarthropathy. The symptoms of ankle soft tissue impingement syndrome are not specific, and the final diagnosis relies on clinical physical examination and MRI. The sensitivity of the ankle impingement test was 94.8% and the specificity 88%, which has some diagnostic value for this disease. The accuracy of conventional MRI examination is not high, and the diagnostic rate of conventional MRI in this group of 14 cases is only 42.86%. The accuracy of MRI is 97%, sensitivity 96% and specificity 100%, which is an important basis for the diagnosis of this disease. Therefore, the diagnosis of this disease should be based on the history, symptoms, physical examination and MRI (imaging). There are different reports on the sites of soft tissue impingement syndrome in the ankle, mainly divided into lateral impingement, anterolateral impingement, medial impingement and posterior impingement, and some literature divided medial impingement into anteromedial impingement and posterior medial impingement. The proportion of anterolateral impacts was close to the total of 19 (61%,19/31) in this group. It can be seen that anterolateral impingement is more common than other sites, which is related to the high incidence of anterolateral tissue injury due to ankle inversion injury, and the abnormal thickening of the distal bundle of the inferior tibiofibular anterior ligament is also a cause. In the literature, impingement tissues are roughly divided into five categories: synovial tissue, ligament fibers, scar, distal bundle of the inferior tibiofibular ligament, and meniscus-like tissue. The pathological examination of the impinging soft tissue in our group also confirmed the above tissue classification, among which synovial impingement was the most common. Local tissue hyperplasia due to trauma, with increased content and embedding in the joint, was the main cause of impingement. The impingement caused by thickening of the distal bundle of the anterior tibiofibular ligament was due to both congenital and traumatic factors. In particular, three cases were impingement of meniscus-like tissue with typical meniscus-like manifestations microscopically and pathology with focal chondrogenesis, which was formed by repeated friction of the impinging tissue and induced chondrogenesis, or may be congenitally formed tissue. There was no significant correlation between the site of impingement and the site of cartilage injury in our group of 16 cases with combined cartilage injury (P = 0.112). Due to the limitation of the number of cases, the relationship between the two should be determined after further study. Treatment of soft tissue impingement syndrome of the ankle joint includes conservative and surgical treatment. Conservative treatment includes physical therapy, braking rest, oral NSAIDs, rehabilitation exercises and local closure therapy, while the definitive treatment is arthroscopic removal of the impinging tissue.Gulish et al [11] arthroscopically treated 25 cases of anterolateral soft tissue impingement syndrome in adolescents with a follow-up of 12 cases, 11 had an AOFAS score of more than 85 with a 100% satisfaction rate, except for 3 cases that did not recover due to re-injury. Kim et al [2] arthroscopically treated 52 cases of anterolateral soft tissue impingement syndrome, divided into two groups of joint stability and joint instability, with an average follow-up of 30 months and an overall treatment excellent rate of 94%, with no significant difference in treatment outcome between the two groups, which means that whether the joint is stable or not has no effect on the treatment outcome of this disease. Wang Lide et al [12] performed arthroscopic treatment in 30 cases of anterior internal and anterior external soft tissue impingement syndrome with an average follow-up of 28 months, with an excellent rate of 87% and a satisfaction rate of 100%. From the literature, the results of arthroscopic treatment are relatively satisfactory. Liu Hongtao et al. treated 36 cases of soft tissue impingement syndrome of the ankle joint with an excellent rate of 77.8%, but 14 cases in this group were treated by incisional surgery, so the excellent rate may be affected. Our group also used arthroscopic resection of impingement tissue to treat this disease, and applied the AOFAS evaluation system for pre- and post-operative assessment, and the overall score improved significantly after surgery compared with that before surgery, with all but one case above 85 points. The subjective score (pain) was higher than 30 after surgery, which was a significant improvement compared to the preoperative score, and the patient satisfaction rate was 90%. 2 patients showed improvement in pain and activity level, and the postoperative AOFAS score also improved compared to the preoperative score, but they considered the results unsatisfactory because they did not reach the pre-injury activity level, but were willing to undergo the same surgery or recommend it to others. The rest of the patients were close to or at the pre-injury level of motion. This shows that the overall results of arthroscopic treatment of this disease are good. In patients with combined joint instability, the results of arthroscopic treatment alone for this disease combined with joint instability are inconclusive, although some literature suggests that joint instability does not affect the results, but the results are better if the joint stability is restored while treating the impingement, which also helps to reduce or avoid secondary injuries due to joint instability. The surgical procedure is not very difficult, and the most important aspect for a physician skilled in the use of knee arthroscopy is the choice of approach. The anterolateral approach should be located at the lateral border of the third peroneal tendon or extensor tendon, with careful subcutaneous separation to avoid injury to the superficial peroneal nerve. The arthroscope can clearly show the subcutaneous vascular nerves by shining the anteromedial space from within the joint, so that damage to these tissues can be avoided during the anteromedial approach. In addition to observing the anterior, medial and lateral ankle spaces, it is important to examine the talofibular and talotibial spaces, which are prone to soft tissue embedding and free body concealment. The arthroscopy is best performed with a 1.9 mm, 2.5 mm, or 2.7 mm small arthroscope, which is particularly convenient for joints with relatively small gaps, and can even be used to extend the small arthroscope into the posterior joint cavity from the anterior approach for exploration and manipulation. 30º2.7 mm arthroscope is used. 70ºarthroscope is useful for exploring the talar neck and the posterior ankle from the anterior approach, and can be flexibly used intraoperatively. The arthroscope is flexible for intraoperative exchange. The surgical instruments used are a small medullary forceps, a small planer, and a probing hook, which facilitate manipulation. A curved planer can also be used to clean the deep part of the joint. Instruments such as radiofrequency vaporizer, microscopic electric knife or laser can also be used when necessary, but are not required. Overall, soft tissue impingement syndrome of the ankle is mostly caused by trauma and has a variety of pathological manifestations. The main clinical symptoms are joint pain and limitation of motion, and impingement tests and MRI (imaging) are the main basis for the diagnosis of this disease. Arthroscopic treatment of soft-tissue impingement syndrome of the ankle is currently the ideal treatment and should be used when conservative treatment is not effective.