Arthroscopic treatment of ankle impingement syndrome

Abstract

Arthroscopic treatment of ankle impingement syndrome (AIS) is a minimally invasive surgical procedure used to address symptoms caused by impingement in the ankle joint. This syndrome occurs when there is abnormal contact between certain bones or soft tissues in the ankle, leading to pain, swelling, or limited range of motion. Traditionally, open surgery was the standard approach for treating AIS. However, with advancements in technology and surgical techniques, arthroscopic treatment has become a preferred method for many patients and surgeons. With improved visualization and precise treatment of the arthroscopy, patients can experience reduced pain and improved functionality, allowing them to return to their daily activities sooner. In this paper, we reviewed the application and clinical efficacy the of arthroscopic approach for treating AIS, hoping to provide a reference for its future promotion.

Introduction

Ankle impingement syndrome (AIS) encompasses a group of disorders in which friction occurs between the joint and surrounding tissues due to various reasons, leading to pain.¹ It is a common clinical condition characterized by severe pain during activity within the ankle joint. The ankle joint is highly congruent, and even minor structural abnormalities can result in varying degrees of secondary changes. Prolonged physical activity can exacerbate the symptoms and eventually lead to irreversible degeneration of the ankle joint. Clinically, this condition is often characterized by ankle joint effusion, synovial proliferation, and osteophyte formation, making it challenging to diagnose and treat.²

Ankle fractures, sprains, and prolonged excessive use of the ankle joint often lead to overgrowth of the synovium and injuries to the ligaments or cartilage, which are early factors contributing to AIS and are easily overlooked. Misdiagnosis in the early stage often occurs, leading to persistent symptoms, accelerated ankle joint degeneration, long-term irreversible pain in patients, and even the need for joint arthroplasty or arthrodesis. In recent years, the diagnosis of AIS has improved due to advancements in imaging technology.³

Clinical manifestations of AIS

The characteristic clinical manifestations of this condition include ankle pain, swelling, and restricted joint mobility. The imaging manifestations vary depending on the location and mode of impingement. Based on the anatomical sites of impingement, it can be classified into anterior ankle impingement syndrome (AAIS), anterolateral ankle impingement syndrome (ALAIS), anteromedial ankle impingement syndrome (AMAIS), posterior ankle impingement syndrome (PAIS), and posteromedial AIS. The most common are AAIS, ALAIS, and PAIS.⁴ According to the etiology, it can be further classified into osseous impingement, soft tissue impingement, and combined osseous/soft tissue impingement. Osseous impingement factors include the presence of a Stieda process, elongated posterior process of the talus, hypertrophic posterior process of the talus, increased slope of the posterior edge of the tibia, and loose bodies in the posterior ankle; soft tissue impingement factors include posterior tibiofibular ligament injuries, posterior deltoid ligament injuries, posterior talofibular ligament injuries, ankle ligament injuries, flexor hallucis longus (FHL) tendonitis, tibiotalar and subtalar arthritis, synovial proliferation, and edema in the surrounding fat.⁵

AAIS is the most common cause of chronic pain in the anterior ankle that worsens with dorsiflexion. Morris⁶ first reported these impingement manifestations in athletes in 1943, and McMurray⁷ later named it “footballer's ankle”. This term was subsequently extended to other populations by O'Donoghue⁸ in the 1950s. The typical symptoms are chronic pain in the anterior ankle and a history of recurrent ankle sprains. Physical examination reveals soft tissue swelling of the ankle joint, localized tenderness in the anterior ankle, limited dorsiflexion function, and a range of motion of the calcaneus and tibia less than 60°. ALAIS often occurs secondary to lateral collateral ligament injury and abnormal thickening of the soft tissues in the anterolateral recess caused by varus ankle joint. AMAIS is less common, and the potential causes are not clear. It may be secondary to repetitive, forceful rotational valgus injuries with tearing of the deep fibers of the medial collateral ligament, impingement of the thickened anterior portion of the medial collateral ligament on the talar dome, and impingement between the tibia and the lateral malleolus. This leads to cartilage damage and the formation of osteophytes. The main clinical symptoms are focal tenderness and swelling in the anterior inferior of the medial malleolus, worsening when the foot is passively everted, and a positive in the drawer test.⁹ PAIS, also known as os trigonum bone impingement syndrome, is characterized by chronic, recurrent pain and limited dorsiflexion caused by increased stress on the posterior process of the talus and the posterior tibia, compressed soft tissues around the calcaneus, in cases of acute trauma, ankle joint plantarflexion, or excessive plantarflexion.10, 11, 12, 13 It is common among individuals who frequently perform plantarflexion activities, such as ballet dancers and football players.¹⁴ In some reports, PAIS is often misdiagnosed in children and adolescents, and awareness of this condition needs to be increased in the diagnosis of young patients.^15,16 Posteromedial AIS is clinically and radiologically rare, and represents the least common type of AIS. Cedell fracture, which involves posterior talar process fracture with injury to the posteromedial tubercle due to forced dorsiflexion, is a rare and easily missed fracture that can cause posteromedial impingement of the ankle joint.¹⁷ This may occur due to the displacement of bone fragments compressing the surrounding structures. In addition to clinical manifestations of symptoms and signs such as local tenderness, diagnosis of AIS may be assisted by an ankle impingement test. For example, anterior ankle pain during dorsiflexion or posterior ankle pain during plantarflexion may indicate positive. To further confirm the diagnosis, lidocaine 1% can be injected into the painful area to see if the pain is significantly relieved.

Conservative treatment for AIS

Conservative treatment is often preferred for the early stage of AIS, to relieve symptoms and enhance the patient's quality of life. Conventional conservative treatment includes physical therapy, strengthening exercises, activity adjustments, braces, and non-steroidal anti-inflammatory drugs.¹⁸ In the clinical management of AIS, standard anti-inflammatory and analgesic methods are commonly used, such as applying ice, and taking non-steroidal anti-inflammatory drugs to alleviate pain symptoms. Additionally, immobilization with a plaster cast is applied to restrict ankle movement. Techniques such as tendon massage and strength training are utilized to promote the recovery of ankle joint function. Literature reports a success rate of 60% − 84% for non-surgical treatment of AIS over 3 − 6 months.¹⁹ For conditions such as tenosynovitis caused by soft tissue impingement, local steroid injections, and oral non-steroidal anti-inflammatory drugs are commonly used in the early stages to quickly relieve pain symptoms, but they should not be used long-term due to potential adverse reactions. Ribbans et al.²⁰ indicated that non-surgical treatment was more effective for soft tissue impingement in AIS. Kudaş et al.²¹ treated 10 patients with AIS using oral anti-inflammatory drugs and physical therapy, and after 4 weeks of treatment, there were increases in the American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot scores for 6 patients and decreases in the visual analogue scale (VAS) pain scores. Opdam et al.²² found that local injection of corticosteroids under ultrasound guidance effectively alleviated pain symptoms in AIS. However, there are conflicting reports on the success rate of corticosteroid injections, and the safety of such drugs remains unclear, thus multiple short-term injections are not recommended.²³ Nazarian et al.²⁴ treated 49 patients with AAIS using ultrasound-guided percutaneous injection of corticosteroids, resulting in a decrease in the foot pain level VAS score from (6.76 ± 1.84) points to (2.73 ± 2.21) points. However, for 10 patients with no significant improvement in clinical symptoms, surgical methods were chosen for further treatment. While non-surgical treatment can relieve pain symptoms in AIS, there is a possibility of recurrence. Overall, the efficacy of conventional treatment is limited, often resulting in slower patient recovery and uncertain therapeutic effects.²

Arthroscopic surgical treatment of AIS

Ankle arthroscopy was attempted by surgeons many years ago, but due to the narrow ankle joint space, these all went unsuccessfully. Therefore, ankle arthroscopy has not been widely developed and applied for a long time since its invention.^25,26 In the 1980s, with the improvement of arthroscopic equipment and the introduction of new devices, such as radiofrequency devices, arthroscopic techniques rapidly advanced. Ankle arthroscopy has been increasingly applied in the diagnosis and treatment of ankle joint diseases and has gradually become the main method for diagnosing and treating AIS.²⁷ The advantage of this technique lies in its ability to directly observe the ankle joint, the subtalar joint, and adjacent structures through small incisions, allowing targeted treatment of lesions.^28,29 Postoperative pain of ankle arthroscopy is minimal, complications are few, and recovery is rapid, enabling patients return to sports early. Therefore, this technique is widely accepted by medical practitioners and the patients.

Arthroscopic treatment for AAIS is reliable and has become a routine technique. During the procedure, it is important to completely remove osteophytes, with normal subchondral bone and articular cartilage serving as the boundaries for osteophyte resection.³⁰ The patient's position is determined depending on the surgical site of resection. For anterior lesions, the supine position is commonly chosen; for posterior lesions, the prone position is selected, and some surgeons may choose the lateral position. The resection area of the anterior ankle osteophyte is also the key content during surgery. Since osteophytes have no hyaline cartilage attachment, resection can be stopped when reaching the hyaline cartilage area; if necessary, arthroscopic monitoring can be applied for an impingement test to confirm that there is no bone or soft tissue impingement during ankle joint movements. Before the end of surgery, C-arm fluoroscopy can be used for confirmation. Preoperative three-dimensional (3D) CT image-reconstruction also helps to determine the range of bony impingement, and the promotion and application of 3D printing technology in recent years has also created conditions for accurate guidance of surgery.³¹ One of the authors (Xiao-Jun Duan) treated a 15-year-old male patient with right AAIS. After arthroscopic treatment, the patient's postoperative pain is significantly relieved and motor function is improved (Fig. 1). A follow-up study by Cavallo et al.³² suggested that patients with normal preoperative ankle joint spaces or less pronounced ankle joint degeneration experienced more satisfactory postoperative outcomes. For pain caused by the posterior process of the talus, van Dijk et al.³³ reported satisfactory results in 2000 using a prone position and medial and lateral incisions next to the Achilles tendon to remove the symptomatic os trigonum bone. It is crucial to identify the FHL tendon intraoperatively, and operating on its lateral side helps avoid vascular and nerve damage. Ankle arthroscopic debridement is an effective method for removing osteophytes and diseased soft tissue, restoring normal range of motion of ankle joint, and has advantages such as minimal trauma and quick functional recovery. It is the preferred surgical method for treating AAIS.³⁴ Complications of ankle arthroscopic debridement for AAIS include incision infection, nerve, tendon, and ligament injuries, with nerve injury being the most common.³⁵ A meta-analysis conducted by Simonson et al.³⁶ regarding complications of arthroscopic treatment for AAIS showed an incidence rate of approximately 4%. Currently, there is controversy among scholars regarding the use of tourniquets during arthroscopic surgery.^35,37, 38, 39 Most clinicians believed that tourniquet use could improve visibility during arthroscopic procedures, but Ahn et al.³⁵ argued that tourniquet use during ankle arthroscopic debridement was a significant factor contributing to complications such as nerve injury, soft tissue injury, and deep venous thrombosis, etc. A study by Zaidi et al.³⁷ found that tourniquet use during ankle arthroscopy had no significant impact on visibility or operative time, suggesting that not using a tourniquet did not affect the arthroscopic visualization of the ankle joint. Yabiku et al.⁴⁰ conducted a cross-sectional study that found athletes with AAIS might have more severe cartilage lesions than non-athletes and suggested that osteophyte protrusion should be assessed before applying arthroscopic treatment for AAIS. Due to the narrow ankle joint space, increasing the ankle joint space through traction can expand the field of view and improve clarity during ankle arthroscopy. Previously, invasive traction increased the incidence of complications such as infection and vascular and nerve damage, while non-invasive traction significantly reduces relevant complications.^41,42 The anteromedial and anterolateral approach are the conventional 2-portal approach for anterior arthroscopy. Wang et al.⁴³ introduced a 3-portal approach by adding an additional anterior median approach and conducted a propensity score-matched analysis. They reported that both the 2-portal and the 3-portal approach of arthroscopy showed good results with no statistically significant difference, and suggested that for the patients with more serious illness, the 3-portal approach was better.

Fig. 1.

Arthroscopic treatment for a 15-year-old male patient with AAIS. (A) Preoperative lateral ankle radiograph shows bony impingement of the anterior ankle, and the white arrow show osteophyte formation of bony impingement; (B) Anterior ankle osteophytes under arthroscope before surgery (black arrow); (C) Osteophyte resection under arthroscope after surgery (black arrow); (D) Postoperative lateral ankle radiograph shows complete resection of the anterior ankle osteophytes.

Treatment of PAIS with arthroscopic technique generally involves using both the posteromedial approach and posterolateral approach. Blázquez et al.⁴⁴ found that the use of arthroscopic technique with 2-portal approach for the treatment of PAIS yielded good results. Maffulli et al.⁴⁵ used a double posteromedial portal technique for arthroscopic management of PAIS in athletes, and demonstrated that this technique with the patient in a supine position was safe and could have satisfactory results. During arthroscopic surgery, the FHL tendon can be identified through dorsiflexion of the ankle or examination of the first metatarsophalangeal joint, which can avoid damaging the nerves and blood vessels surrounding the tendon while removing the impinging bone. In addition, after resection of the os trigonum bone under arthroscope, the impingement or compression of the FHL tendon can be examined to determine whether repair or release of FHL is necessary. As for the comparison between open surgery and arthroscopy for PAIS, Guo et al.⁴⁶ conducted a study comparing the outcomes of traditional open surgery and arthroscopic technique for the treatment of PAIS in 41 patients. The study showed no significant differences in the AOFAS scores and VAS scores between the 2 groups, but the arthroscopic group had an earlier postoperative recovery time. Carreira et al.⁴⁷ found that arthroscopic technique for the treatment of PAIS resulted in fewer complications, improved foot function, and shorter recovery time. Xiang et al.⁴⁸ also reported that posterior ankle arthroscopy had shown promising results in treating symptomatic os trigonum, with faster recovery and return to previous activity levels compared to open surgery.

Common pathological types of ALAIS include localized synovial hyperplasia, fibrous band, anterior tibiofibular ligament tear, and local scars. Moustafa El-Sayed⁴⁹ reported the arthroscopic outcomes of 25 patients with ALAIS. During surgery, 65% of the patients showed synovial tissue hyperplasia, 10% had fibrous band in the anterior region of the anterior tibiofibular ligament, 15% had tears in the anterior tibiofibular ligament, and 10% had local scar thickening. Symptom relief was achieved after surgical removal of the lesioned soft tissues, with an overall excellent rate of 85%. Patients with tears in the anterior tibiofibular ligament had slightly worse surgical outcomes. For concomitant cartilage injuries, the effect on the outcomes was not significant due to the mild nature of the injuries.

Ankle soft tissue impingement syndrome (ASTIS) is a common cause of chronic ankle pain. In ASTIS patients, the soft tissues of the ankle joint produce inflammatory mediators, leading to synovial tissue hyperplasia and osteophyte formation.⁵⁰ ASTIS can occur in the anterior, posterior, anteromedial, and anterolateral aspects of the ankle joint.^51,52 Among them, anterolateral ASTIS is the most common type in clinical practice. Changes in the anatomical structures and biomechanical characteristics of the ankle joint occur in ASTIS patients, and in the advanced stage, severe ankle pain and functional impairments may develop. Arthroscopy is commonly used for the diagnosis and treatment of ASTIS. Parma et al.⁵³ treated patients with anterior ASTIS using arthroscopic debridement and followed them for 9 years. They found a significant improvement in postoperative AOFAS scores compared to preoperative scores. In the systematic review of Zwiers et al.⁵⁴, they reviewed studies using arthroscopic treatment for anterior ASTIS patients with an average follow-up period of 35.3 months; patient satisfaction was reported in 6 studies and 74% – 100% of the patients were satisfied with the surgical outcomes; in another 2 studies, the incidence of postoperative complications was 5.1%. Devgan et al.⁵⁵ treated 14 patients with anterior ASTIS using arthroscopic debridement and followed up them for 15 months. The results were excellent in 11 cases, good in 2, and poor in 1. The AOFAS scores improved from 50.5 points preoperatively to 85.71 points postoperatively. Arthroscopic debridement for ASTIS minimizes the trauma to the patients, allows for the observation of any remaining proliferative matter within the joint during repeated ankle flexion and extension activities, and lowers the incidence of postoperative complications while facilitating a faster recovery process.⁵⁶ Arthroscopic debridement for ASTIS also allows for the identification and timely treatment of concomitant diseases such as cartilage injuries and loose bodies, which could yield significant improvement in ankle joint function and have a low incidence of postoperative complications.

The current mainstream arthroscopes have a diameter of 4.0 mm, which are primarily used for larger joint cavities such as the knee and shoulder joints. For smaller joints such as the ankle joint and subtalar joints, a 2.7 mm arthroscope is commonly used. Consequently, in the 1990s, needle arthroscopy (NA), with an even smaller diameter, emerged as a technique for visualizing and evaluating joints. Initially, NA had many limitations and was not widely used, but with continuous product iterations, the latest NA systems can visualize the joints and be used for surgeries under local anesthesia in the office or at the bedside.⁵⁷ Moreover, the new in-office needle arthroscopy (IONA) system now has instruments that were previously unavailable, allowing for relevant operations during the joint exploration process, and for patients to have reduced anesthesia expenses and fewer surgical risks.^58,59

In a retrospective cohort study on IONA treatment for PAIS, Mercer et al.⁵⁷ evaluated the efficacy and patient satisfaction of IONA treatment for PAIS. All 10 patients reported similar or lower pain-related results compared to preoperative scores, as well as higher functional, quality of life, and daily living activity scores. The authors concluded that IONA treatment for PAIS could significantly reduce pain, lower complication rates, achieve better patient-reported outcomes, and, more importantly, have high patient satisfaction. IONA is also suitable for the treatment of AAIS. In a prospective study, Colasanti et al.⁶⁰ followed 31 anterior ankle impingement (AAI) patients treated with IONA with a minimum follow-up period of 12 months. In their study, 27 patients (87%) preferred receiving the procedure in an outpatient setting rather than in the operating room, and 29 patients (94%) expressed willingness to undergo the same surgery again. The study indicated that IONA treatment for AAI could significantly reduce pain, lower complication rates, yield excellent patient-reported outcomes, and have a high probability of returning to work or physical activity, resulting in high patient satisfaction. For patients suspected of having PAIS or AAI, IONA has significant advantages in making prompt and efficient diagnoses and providing simultaneous treatment, thus reducing healthcare costs. The examination and treatment results are comparable to traditional methods. Additionally, patient satisfaction is higher; therefore, IONA is recommended for the treatment of PAIS and AAI.

However, NA technology also has some technical limitations. The NA lens angle is 0°, unlike other arthroscopic lenses with a 30° angle. Orthopedic surgeons using NA are unable to observe the entire joint cavity by rotating the camera and need to change the view by tilting the entire arthroscope. This requires some time and a learning curve for orthopedic surgeons who are new to NA. If patients have osteophyte or impingement syndrome, the possibility of tilting the arthroscope is limited, which may hinder intraoperative visualization of the joint. Besides, NA also has a relatively lower resolution.^57,61 The IONA system provides feedback on the intra-articular view through an external 13-inch display screen, which has lower image quality compared with the 4 K-resolution screens used in traditional arthroscopy.

Treatment of AIS with accompanying comorbidities

Arthroscopic treatment of ankle joint instability combined with AMAIS

Studies have shown that 86% of patients with ankle instability are associated with soft tissue impingement and 26% with osseous impingement.⁶² Odak et al.⁶³ reviewed 100 cases of surgical treatment for ankle instability and found that 63% (63/100) had soft tissue impingement and 12% (12/100) had osseous impingement. A small sample study showed that 25% of ankle sprains resulted in anterior impingement.⁶⁴ Murawski et al.⁶⁵ reported that among 41 patients with anteromedial impingement syndrome, 6 cases had concomitant lateral ligament injury, 3 had concomitant osteochondral lesions of the talus, and 1 had concomitant lateral ligament injury and osteochondral lesions of the talus. The average follow-up period was 34.41 months (24 − 52 months), AOFAS ankle-hindfoot scores improved from 62.83 points preoperatively to 91.17 points postoperatively; 36-item short form survey (SF-36) scores improved from 61.54 points preoperatively to 92.21 points postoperatively. A total of 40 cases returned to their previous level of sports activity. There were 3 cases who had postoperative complications (7%), including 1 of superficial peroneal nerve injury (recovered after 6 weeks postoperatively), 1 of joint fibrosis, and 1 of reflex sympathetic dystrophy. The midterm follow-up results of Arrondo et al.⁶⁶ also showed significant therapeutic effects of arthroscopic treatment for anteromedial impingement syndrome of the ankle. AMAIS combined with ankle joint instability is easily overlooked in clinical practice. These patients often have osteophyte on the medial side of talar neck, which can obstruct the proper placement of the ankle joint during arthroscopy, hindering the clearance of the medial gutter and impeding the repair of the lateral ligament. Arthroscopic removal of talar neck osteophyte can effectively treat ankle instability combined with AMAIS, with precise therapeutic effects, minimally invasive and safe, and worthy of promotion.

Arthroscopic treatment of PAIS combined with flexor hallucis longus tendinopathy

PAIS is a syndrome of bone and soft tissue impingement caused by acute inversion or repeated excessive plantarflexion activities of the ankle joint. When the ankle joint is excessively plantarflexed, the FHL tendon can develop tendinitis or tenosynovitis due to repeated impingement or friction, leading to longitudinal tearing or rupture of the FHL tendon.^67,68 The 2 conditions can coexist or exist separately.⁶⁷ Most patients respond well to non-operative treatment, but surgery is needed when non-operative treatment is ineffective, including open surgery and arthroscopic minimally invasive surgery. Lui et al.⁶⁹ pointed out through dissection and measurement of 14 ankle joint samples from 7 cadavers that the risk of injuring the posterior tibial neurovascular bundle was higher when operating through the posteromedial approach compared to the posterolateral approach. Mak et al.⁷⁰ applied the double posterolateral portal approach to access the posterior ankle joint cavity and achieved satisfactory clinical outcomes by operating and treating the PAIS and decompressing the FHL tendon without damaging the posterior tibial neurovascular bundle. Therefore, in patients with PAIS combined with FHL tendinopathy, when non-operative treatment fails, arthroscopic surgery can be used to achieve minimally invasive treatment, allowing for thorough decompression of the FHL tendon and improvement of ankle joint function.

For osseous PAIS combined with FHL tenosynovitis, Rietveld et al.⁷¹ believed that PAIS, FHL tenosynovitis, or PAIS combined with FHL tenosynovitis had their pathological basis. Simple resection might not relieve the clinical symptoms caused by FHL tenosynovitis. Therefore, combined surgery to treat both osseous PAIS and FHL tenosynovitis could be conducted. Heyer et al.⁷² achieved good surgical results by performing an excision of the os trigonum through an open approach and simultaneous release of the FHL tendon. Nishimura et al.⁷³ repaired and sutured the FHL according to the extent of its injury during the treatment of PAIS. Compared to open surgery, arthroscopic surgery has significant advantages, as it can achieve the same goals as open excision and can simultaneously address FHL tenosynovitis. It has smaller trauma and avoids the scar adhesions and other complications caused by excessive length of the surgical incision.

Summary

Arthroscopy of the ankle joint is the most effective treatment approach for AIS as it allows for a definitive diagnosis and corresponding treatment. It particularly demonstrates significant efficacy in relieving ankle joint pain and swelling, greatly alleviating patient suffering, and improving their quality of life, which is a safe and effective treatment option.⁷⁴ Although ankle arthroscopy plays an important role in the diagnosis and treatment of ankle conditions, its popularity is currently lower than that of knee and shoulder arthroscopy. This could be attributed to the narrow operating space and long learning curve of ankle arthroscopy, where the lack of proficiency may significantly affect surgical outcomes; the difficulty in diagnosing ankle disorders, such as chronic lateral ankle pain following trauma, which often involves controversies in differentiating between tibiofibular syndesmosis injury, ankle joint instability, or subtalar instability; and the lack of dedicated instruments. With an in-depth understanding of foot and ankle pathologies, the indications for ankle arthroscopy may become more refined. Moreover, a large number of arthroscopy surgeons who have received specialized training can help reduce surgical complications, while the development and popularization of specialized instruments can further enhance surgical outcomes.

Funding

Chongqing Postgraduate Education and Teaching Reform Research Project (No. yjg203136); Army Medical University Graduate Teaching Program (Y2022W04).

Ethical statement

Not applicable.

Declaration of competing interest

All authors declare no competing interest.

Author contributions

Xin Chen and He-Qin Huang wrote and revised the manuscript.

Xiao-Jun Duan designed and supervised the study.