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Chronic ankle instability

91 citationsUpdated Sep 2026

Overview

Chronic ankle instability is a condition where persistent ligamentous laxity leads to reduced self-reported function compared to healthy individuals or those who have recovered from acute sprains [4]. The clinical picture is often complicated by chronic syndesmotic or medial ankle instability, both of which are significantly associated with unsatisfactory outcomes [1]. While a consensus exists on identifying patients who require surgery, the optimal intervention, and the role of arthroscopic treatment [2], surgical practices remain heterogeneous, particularly in specific clinical situations [32]. Assessment is critical because operative procedures focusing only on part of the pathology should be approached with caution until all deficiencies are defined [43]. Arthroscopy provides more accurate information than current imaging studies for the definitive assessment of ligament lesions [20]. Although the clinimetric qualities of the Foot and Ankle Ability Measure (FAAM) require further demonstration in this specific population [30], it remains a key tool for evaluating functional status.

Initial management of chronic lateral ankle instability, particularly in military service members, involves appropriate nonoperative treatment [3]. Surgical management is warranted when nonoperative treatment fails to prevent long-term sequelae [3]. A randomised controlled trial protocol has been designed to determine the effects of mobilisation with movement on anatomical and clinical characteristics, including long-term effectiveness at 12 months [5]. When surgery is indicated, options include anatomic direct repair, anatomic reconstruction with an autograft or allograft, and arthroscopic repair [151]. Symptomatic chronic lateral ankle instability can be successfully managed with surgical reconstruction methods [6]. Arthroscopic diagnosis and treatment of associated intra-articular lesions is a safe and effective method [9], and arthroscopic treatment is emerging as the potential gold standard technique, offering the advantage of addressing both instability and associated pathology in a single procedure [78].

While only fair-quality evidence exists in support of open operative treatment, systematic review data help reassure clinicians of their current practices [11]. Arthroscopic ankle stabilisation repair and reconstruction techniques hold considerable promise but require further evaluation to determine indications of repair versus reconstruction and to obtain information on long-term outcomes [65]. Clinical and radiologic outcomes improve after all-inside arthroscopic anterior talofibular ligament repair [12], where additional inferior extensor retinaculum augmentation is not necessary [12]. Ultrasound-guided anterior talofibular ligament repair with or without augmentation is safe and results in clinical improvement at 6 months [22]. Lateral ligament reconstruction with allograft represents a valid treatment option in patients with severe chronic lateral ankle instability, leading to satisfying outcomes and reduced joint morbidity [33]. An arthroscopic Broström procedure results in resumed ankle stability with a high clinical success rate at mid-term follow-up [39]. Combined treatment of chronic ankle instability and anterior ankle impingement produces satisfactory surgical outcomes [8], and ligament stabilization with arthroscopic procedures for individuals with chronic ankle instability and medial ankle osteoarthritis yields significant functional outcomes with high patient satisfaction, even without radiographic improvement [67]. The literature would benefit greatly from the standardization of the definition of ankle instability treatment failure [44].

Anatomy & Pathophysiology

Bony Anatomy

The ankle mortise is formed by the tibial plafond, medial malleolus, and lateral malleolus, which articulates with the dome of the talar body [83]. During motion from plantar flexion to dorsiflexion, the mortise widens 1 to 1.5 mm [83]. The ankle becomes more stable in dorsiflexion owing to the shape of the talar dome, which is wider anteriorly and narrower posteriorly [83]. The distal tibiofibular joint consists of the convex medial surface of the distal fibula and the concave incisura fibularis of the distal lateral tibia [83]. The fibula rotates approximately 2 degrees within the incisura during ankle motion and ambulation [83]. Ankle dorsiflexion results in external rotation and proximal translation of the fibula [83].

Radiographic parameters define normal alignment. The talocrural angle is approximately 83 degrees and symmetrical with the contralateral ankle [94]. The medial clear space should be less than 5 mm and no more than 2 mm greater than the tibiotalar clear space [94]. The tibiofibular clear space 10 mm above the joint line is relatively constant with rotation and has an accepted normal parameter of greater than 5 mm [94]. The tibiofibular overlap 10 mm above the joint line is highly variable dependent on rotation, with accepted normal parameters of less than 5 mm on AP view and less than 1 mm on the mortise view [94]. The "ball sign" on the AP view is an unbroken curve connecting the recess in the distal tip of the fibula and the lateral process of the talus when the fibula is out to length [94]. Shortening of the fibula results in lateral and valgus subluxation of the talus [94]. The size of the medial clear space more than doubles depending upon the rotational position of the limb [94]. There is a significant increase in medial clear space with ankle plantarflexion [94].

Ligamentous Anatomy

The lateral ankle ligaments function as restraints to varus and inversion forces at the ankle [83]. The anterior talofibular ligament (ATFL) originates from the anteroinferior aspect of the lateral malleolus, 1 cm proximal to its tip, and extends to the lateral aspect of the talar neck [83]. The calcaneofibular ligament (CFL) extends from the tip of the lateral malleolus to the lateral aspect of the calcaneus [83]. The posterior talofibular ligament (PTFL) extends from the posterior lateral malleolus to the posterolateral talus [83]. The ATFL is the weakest ankle ligament, while the PTFL is the strongest [83]. The distal tibiofibular joint and fibula provide stability against lateral talar translation [83].

The deep deltoid ligament extends from the apex of the medial malleolus to the medial talar body and functions primarily to resist lateral talar translation and external rotation [83]. The posterior deep deltoid is the most important component of the deltoid ligament complex [83]. The superficial deltoid ligament extends from the distal medial malleolus to the navicular bone, sustentaculum tali of calcaneus, medial talus, and spring ligament [83]. The superficial deltoid ligament functions primarily to resist valgus and eversion ankle forces [83]. The deltoid ligament complex is the primary ankle stabilizer during stance [83].

Biomechanical testing reveals distinct failure modes. The deep deltoid ligament has the highest load to failure at 713.8 N ± 69.3 compared with the lateral collateral ligaments [91]. The dominant mode of failure for the deep deltoid ligament occurs as an intrasubstance rupture near its talar insertion [91]. The failure of the superficial deltoid ligament is most commonly at its insertion on the anterior malleolus [91]. The deltoid ligament has a rich vascular supply from three separate extraosseous sources: the medial tarsal artery, the posterior tibial artery, and the tibialis anterior artery [91]. The deltoid ligament also has a component of intraosseous vascular supply from either the talus or the medial malleolus [91]. The CFL contributes to both ankle and subtalar stability [73]. Subtalar instability is difficult to directly differentiate from ankle instability because the CFL contributes to the stability of both joints [73].

Pathophysiology

Chronic ankle instability is a multifactorial condition involving mechanical and functional insufficiencies resulting from primary ankle sprain [16]. Deformities such as hindfoot varus, first ray plantar flexion, midfoot cavus, and generalized laxity play a role in the predisposition to lateral ankle sprain [16]. The development of chronic lateral ankle instability can involve abnormal neuromuscular response and proprioception, abnormal gait mechanics, global ligamentous laxity, increased body weight, and anatomic features of the hindfoot and ankle including cavus alignment and hindfoot stiffness [26]. Approximately 30% of those suffering an initial lateral ankle sprain develop chronic ankle instability or repetitive giving way of the ankle during functional activities [144]. Chronic ankle instability is defined by repetitive episodes of giving way with persistence of symptoms and a limitation on self-reported function that persist for greater than 1 year [148].

The pathomechanics of chronic ankle instability are caused by mechanical instability due to ligamentous laxity and functional instability due to deficits in proprioceptive control [148]. Mechanical instability is most commonly associated with pathologic joint laxity [144]. Functional instability is typically ascribed to sensorimotor deficits [144]. The number of mechanoreceptors was negatively correlated with ankle sensorimotor dysfunction in patients with chronic ankle instability [46]. Subjects with chronic ankle instability show less variability in muscle activation patterns between test conditions [10]. Patients with chronic ankle instability had longer electromechanical delay times in neutral but not when the ankle was placed in inversion [64].

Individuals with chronic ankle instability demonstrate altered lower limb biomechanics, particularly greater ankle inversion angles and reduced ankle eversion moments [86]. Athletes with chronic ankle instability had a relatively inverted ankle, reduced muscle co-contraction, and a lower dynamic stiffness in the ankle joint during the landing phase of sports maneuvers [112]. Alterations of kinematics in athletes with chronic ankle instability were found not only at the ankle but also at hip joints during the side-cutting movement [100]. The injured and uninjured sides of individuals with chronic ankle instability demonstrate biomechanical characteristics associated with increased risk of ankle sprain [90]. Chronic ankle instability alters central organization of movement [145]. Treatment of ankle instability may need to account for alterations in brain activity in addition to deficits in the mechanical restraint of the joint provided by the articular, ligamentous, and muscular stabilizers [129].

Three-dimensional talar shape is not a factor in chronic mechanical ankle instability [87]. The dynamic congruency of the joint, which is influenced by ligamentous integrity, remains the main anatomical component in mechanical ankle instability [87]. Valgus rearfoot alignment and poorer dynamic postural control were associated with chronic ankle instability among adolescent athletes [133]. Increased fear of movement is associated with increased ankle joint position sense errors and postural sway in individuals with functional ankle instability [114]. The CAI, coper, and control groups displayed different ankle joint coupling patterns and coordination variability during a walking gait cycle [117]. Dynamic stability deficits are present in athletes with chronic ankle instability, and the direction of the jump can affect dynamic postural stability in the sagittal and frontal planes [138]. Reduced sagittal plane motions at the hip, knee, and ankle joints, and reduced capacity of the stance limb to avail of its supporting base, are observed in individuals with chronic ankle instability compared to ankle sprain copers [106]. Significant differences between players with and without chronic ankle instability were seen in the support leg kinematics at flat-foot contact with the ground during the kicking cycle [115]. The presence of chronic ankle instability negatively affected ankle function and health-related quality of life in adolescent athletes [131]. An acute lateral ankle sprain significantly decreases physical activity across the lifespan [13].

Classification

Pathophysiology: Chronic ankle instability arises from the combination of mechanical and functional insufficiencies resulting from a primary ankle sprain [16]. The clinical hallmarks of this condition include persistent pain, recurrent sprains, and repeated instances of the ankle giving way [16]. Preoperative ankle arthroscopy reveals abnormalities in various structures involved in chronic ankle instability, with no single causal entity identified [29]. Notably, the presence of chronic ankle instability is not correlated with the number of ruptured ligaments in severe anterolateral sprain [165].

Predisposing Factors: Specific deformities play a role in predisposing patients to lateral ankle sprain. These include hindfoot varus, first ray plantar flexion, midfoot cavus, and generalized laxity [16].

Other Considerations: Musculoskeletal Deficits: Patients with chronic ankle instability demonstrate atrophy of intrinsic and extrinsic foot and ankle musculature accompanied by lower ankle strength [17]. Neurological and Sensorimotor Findings: Individuals with chronic ankle instability experience impaired proprioception compared to healthy individuals, while showing no notable differences in key muscle activation patterns [62]. Chronic ankle instability is associated with smaller sensorimotor deficits and greater integrity of the superior cerebellar peduncles with aging [168]. Functional Outcomes: Only subjects with chronic ankle instability had reductions in self-reported function when compared to ankle sprain copers and healthy individuals [4].

Clinical Presentation

Symptoms and History

Chronic lateral ankle instability is frequently encountered in military service members [3]. Patients typically present with a sensation of instability, often accompanied by recurrent and frequent inversion injuries [26]. Symptoms are provoked by walking on uneven ground or participating in athletic activity [26]. The condition can be debilitating to athletes and active individuals, while also hampering activities of daily living in lower-demand patients [16]. Only subjects with chronic ankle instability demonstrate reductions in self-reported function compared to ankle sprain copers and healthy individuals [4]. Decreased perceived ankle and knee joint health is associated with increased symptomology in individuals with perceived chronic ankle instability [25]. Residual ankle symptoms were found in 33 per cent of patients following acute ankle sprains, and persistent abnormal changes of the ankle were found in 60 per cent [15].

Physical Examination

Clinical examination findings for chronic instability may be more subtle than in acute injuries, with minimal ecchymosis and swelling limited to the joint line suggestive of an effusion [16]. Ligament laxity is more easily noted in the patient with chronic instability because the limb tends to be less painful [16]. An ankle effusion may be present because of chronic instability and synovitis or from an associated osteochondral lesion or loose body [26]. Anterior drawer testing and talar tilt stress are performed to evaluate competency of the anterior talofibular ligament and calcaneofibular ligament, respectively [26]. Patients should be assessed for evidence of global ligamentous laxity and weight-bearing hindfoot alignment [26]. Individuals with chronic ankle instability experience impaired proprioception compared to healthy individuals [62]. The number of mechanoreceptors was negatively correlated with ankle sensorimotor dysfunction in patients with chronic ankle joint instability [46].

Imaging and Diagnostic Assessment

Magnetic resonance imaging evaluation can be useful in demonstrating associated causes of ankle pain, such as chondral injury, bone bruising, radiographically occult fractures, sinus tarsi injury, periarticular tendon tears, degeneration, and impingement syndrome [16]. The cardinal signs of ligament injury on magnetic resonance imaging scans are ligament swelling, discontinuity, a lax or wavy ligament, and nonvisualization [16]. MRI does not help determine functional instability in chronic ankle instability [26]. Arthroscopy plays a crucial role in the definitive assessment of ligament lesions in patients with chronic ankle instability, supplying far more accurate information than any of the current imaging studies [20]. Preoperative ankle arthroscopy revealed an essential amount of information that would otherwise have been undetected, showing that abnormalities of different structures are involved in chronic ankle instability with no single causal entity [29]. The sensitivity of MRI may not be adequate to detect lesions in patients with chronic ankle instability before surgery [54]. In a symptomatic patient, negative results on MRI must be viewed with caution and an arthroscopy may still be required for a definitive diagnosis and treatment [54]. A load–displacement ratio measured via digital arthrometer would be a reliable and promising approach for chronic ankle instability diagnosis [27]. Ankle arthroscopy was performed more frequently in female patients and most commonly in patients younger than 50 years, with a significant increase in its use for lateral ankle instability management [19]. Intra-articular pathological findings are observed in patients with anterolateral pain after an ankle sprain despite no demonstrable abnormal lateral laxity [58]. Antero-lateral ankle impingement syndrome is closely linked to anterior talo-fibular ligament injury and, in some patients, to chronic ankle instability [59]. The presence of a symptomatic peroneus quartus muscle should be considered in athletes with chronic ankle pain, swelling, and instability [107].

Investigations

Clinical Examination and Physical Testing

Anterior drawer testing and talar tilt stress are performed to evaluate the competency of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL), respectively [26]. Patients with chronic ankle instability should be assessed for evidence of global ligamentous laxity and weight-bearing hindfoot alignment [26]. The load–displacement ratio measured via digital arthrometer is a reliable and promising approach for the diagnosis of chronic ankle instability [27]. A comprehensive stress radiographic technique has been presented as a reliable and representable measurement tool to assess additional injury or instability of the subtalar joint in patients with chronic lateral ankle instability [45]. Subjects with chronic ankle instability show less variability in muscle activation patterns between test conditions during the transition from double-leg to single-leg stance [10]. Increased symptomology associated with decreased ankle joint health supports information demonstrating joint degeneration in young adults with chronic ankle instability [25].

Imaging

Plain radiography: AP, mortise, and lateral weight-bearing radiographs of the ankle are performed as part of the diagnostic workup for chronic ankle instability [26]. Stress radiographs can be used to confirm instability by obtaining a lateral radiograph while performing the anterior drawer test and a mortise radiograph while performing the talar tilt test [26].

MRI: Magnetic resonance imaging (MRI) is useful in evaluating for associated pathology to the peroneal tendons or talar articular surface [26]. MRI confirms the abnormal appearance of affected ligaments, which may be thickened or indistinct, but does not help determine functional instability [26]. MRI has excellent interobserver reliability (intraclass correlation coefficient, 0.915) for detecting ATFL injuries in patients with clinical suspicion of chronic lateral ankle instability [139]. Preoperative MRI is a helpful tool for evaluation but is not sufficient to detect all associated lesions in patients with chronic ankle instability [164]. Isolated injury to the superior fascicle of the lateral ligaments identified on 3D volumetric MRI may be useful when diagnosing patients presenting with symptoms of subtle instability without overt ankle laxity on clinical examination [166].

Arthroscopy

Arthroscopy remains the gold standard in the diagnosis of associated lesions in patients with chronic ankle instability [164]. Arthroscopy supplies far more accurate information than current imaging studies for the definitive assessment of ligament lesions in patients with chronic ankle instability [20]. Preoperative ankle arthroscopy reveals essential information that would otherwise have been undetected, showing that abnormalities of different structures are involved in chronic ankle instability with no single causal entity [29]. An arthroscopic classification of chronic ATFL lesions confirms the diagnostic role for arthroscopy in assessing ligaments in patients with chronic ankle instability and is helpful for determining the best surgical technique for stabilizing the ankle [42]. The final diagnosis of chronic instability of the anterior syndesmosis can be made during arthroscopy of the ankle [34].

Treatment

Non-Operative

Conservative management for chronic ankle instability centers on functional rehabilitation, specifically peroneal strengthening and proprioceptive training [26]. This structured program may be supplemented with external splinting [16] and bracing [26]. Neuromuscular training paired with functional bracing reduces the risk of recurrent low ankle sprains more effectively than neuromuscular training alone [74]. A supervised impairment-based program has demonstrated superiority over control groups, with effect sizes exceeding the minimal clinically important difference [50]. Conservative measures, including rehabilitation, taping, and bracing, may reduce the occurrence of recurrent sprains and effectively manage chronic instability [54]. In cases of hindfoot varus alignment, an orthotic with a lateral-based wedge is considered [26].

Manual therapy options include high-velocity low-amplitude (HVLA) thrust techniques to improve sensory input to corticospinal pathways, enhancing proprioception and balance [113]. Two randomized controlled trials reported that HVLA techniques reduce pain and improve functional test performance [113]. However, evidence regarding Maitland mobilizations and mobilization with movement (MWM) is conflicting; while range of motion may improve, carryover to functional performance is inconsistent [113]. A case series found no improvement in single-limb stance postural control after six sessions of grade II traction and grade III posterior talar glides [113]. Additionally, a literature review reported weak evidence for ankle joint mobilizations improving performance on the Star Excursion Balance Test [113].

Operative

Indications: Surgical management is warranted when nonoperative treatment fails to prevent long-term sequelae [3]. The primary indication for surgery is the failure of nonsurgical management [16]. Chronic lateral ankle instability is best treated with physical therapy and bracing, followed by direct anatomic repair if nonsurgical treatment fails [73]. Ankle arthrodesis is considered for patients with painful limited motion, failed conservative measures, and arthritis resulting from chronic instability [71].

Surgical Approach / Technique: The most commonly used anatomic repair is the Gould modification of the Broström repair, which involves imbrication of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) with reinforcement using the lateral talocalcaneal ligament and inferior extensor retinaculum [26]. Anatomic procedures closely recreate native anatomy and preserve motion at the ankle and subtalar joints [26]. Numerous studies report greater than 85% excellent results using anatomic repairs at short-, intermediate-, and long-term follow-up [26]. Anatomic stabilization techniques provide superior functional outcomes compared to non-anatomic techniques [68]. Repair of only the ATFL yields similar outcomes to repair of both the ATFL and CFL [13].

Arthroscopic treatment is emerging as a potential gold standard, allowing simultaneous addressing of instability and intra-articular pathology [78]. All-inside arthroscopic ATFL repair improves clinical and radiologic outcomes [12], and additional inferior extensor retinaculum augmentation is not necessary [12]. Arthroscopic all-inside repair with suture augmentation successfully treats instability with poor remnant ligament-tissue quality [49]. A new arthroscopic Broström procedure achieves high clinical success rates [39]. Open and arthroscopic ATFL repairs equally achieve statistically significant functional improvement and address mechanical instability [72]. Both Ahlgren-Larsson and arthroscopic methods are safe and effective [109]. Arthroscopic techniques hold promise but require further evaluation to determine indications for repair versus reconstruction and to establish long-term outcomes [65].

Implant Selection: A tendon graft should be considered to supplement repair in patients with prior surgical failure, generalized ligamentous laxity, or high functional demands [73]. Nonanatomic peroneal tendon procedures (Evans procedure, Chrisman-Snook) or allograft procedures are reserved for recurrent instability after initial operative treatment [74]. Allograft tendon reconstruction of the ATFL and CFL increases ankle stability in clinical and functional outcomes [31]. The application of allogeneic tendons for malunited lateral malleolar avulsion fractures combined with chronic instability appears safe and effective [69]. A popular modification of the modified Broström-Gould technique supplements ligament repair with suture tape affixed to the fibula and talus using knotless anchors, providing increased stability in patients with poor native tissue or other risk factors [26]. This suture tape supplementation may allow for a more rapid and aggressive rehabilitation protocol [26].

Alignment / Balancing Strategy: Malalignment associated with chronic lateral ankle instability must be corrected when considering lateral ligament stabilization [73]. Coleman block testing helps distinguish between fixed and flexible hindfoot varus in this context [73].

Other Considerations: Operative procedures focusing only on part of the pathology should be approached with caution until a comprehensive assessment defines all deficiencies [43]. Although only fair-quality evidence supports open operative treatment, systematic reviews reassure clinicians of current practices [11]. Reconstruction of the lateral ankle ligament is a relatively stable treatment for chronic ankle instability [126]. Symptomatic chronic lateral ankle instability can be successfully managed with easy and effective surgical reconstruction methods [6]. A four-step approach provides a suitable minimally invasive method for mild to moderate ankle instability with long-term functional outcomes [47]. Combined treatment of chronic ankle instability and anterior ankle impingement produces satisfactory outcomes [8]. Newer adaptations of the modified Broström-Gould technique include arthroscopic performance, which may reduce postoperative pain and swelling and allow concomitant evaluation for impingement and osteochondral lesions [26].

Postoperative Management and Outcomes: Two postoperative treatments differing by weightbearing status after the modified Brostrom procedure showed good clinical results and similar outcomes in clinical and radiological parameters [48]. Subtalar stiffness is a common complication after tendon rerouting reconstruction for chronic ankle instability [73]. In one case, a patient undergoing salvage reconstruction using a tendon allograft maintained a stable, painless ankle with no additional instability fourteen years post-procedure [21].

Complications

Neurologic and Soft Tissue: Neurologic complications occur in 10% of patients undergoing arthroscopic ligament repair or reconstruction, manifesting as transient dysesthesia and neuroma [137]. Entrapment of the peroneus tertius, extensor tendons, and the superficial peroneal nerve can occur when tying sutures for the anterior talofibular ligament during arthroscopic repair [137]. In one case of arthroscopic isolated reconstruction of the anterior talofibular ligament with a free ipsilateral gracilis graft, the patient reported transient dysaesthesiae on the dorsolateral aspect of the foot and heel [163].

Wound and Infection: Cutaneous complications and infection occur in 4.2% of patients undergoing arthroscopic ligament repair or reconstruction, requiring surgical revision [137]. The rate of cutaneous complications in arthroscopic ligament repair or reconstruction is at least half that of open surgery [137].

General Complication Rates: Complication rates for arthroscopic repair or reconstruction of the talofibular ligament range between 11.5% and 18% [137]. A systematic review of level IV studies regarding arthroscopic Broström techniques reported a 17% complication rate [137]. Two-stage arthroscopy is associated with significantly higher complication rates compared with single-stage arthroscopy for lateral ligament repair [137]. Higher complications are noted with suture anchor fixation (29%) compared with suture fixation (9%) in arthroscopic ligament repair [137]. Although the complication rate of arthroscopic ligament repair or reconstruction is a concern, it did not seem to affect patient satisfaction in some studies [137].

Arthroscopic Findings and Associated Pathology: Preoperative ankle arthroscopy reveals abnormalities of different structures involved in chronic ankle instability, indicating no single causal entity [29]. Anterolateral impingement is a less frequent finding in chronic lateral ankle instability, presenting with synovitis and fibrosis [137]. Twelve percent of patients with chronic ankle instability have anterior bony impingement [137].

Long-Term Joint Health and Arthritis: Augmented direct anatomical repair and lateral tenodesis for chronic ankle instability do not lead to significant arthritic changes up to 15 years from surgery [66]. Lateral ankle ligamentoplasty provides protection against secondary osteoarthritis in the management of chronic ankle instability [80].

Risk Factors for Unsatisfactory Outcomes: Chronic syndesmotic instability is significantly associated with unsatisfactory outcomes in patients with chronic ankle instability [1]. Chronic medial ankle instability is significantly associated with unsatisfactory outcomes in patients with chronic ankle instability [1].

Recovery

Light activity (weeks): The provided evidence does not specify a typical week range for desk work, driving, or light activities of daily living.

Full activity (months): The provided evidence does not specify a month range for manual work, sport, or full range of motion and strength return.

Complete recovery / outcome plateau (months): The provided evidence does not specify a month range for the stabilization of pain, strength, and final functional outcomes.

Rehabilitation protocol: The success of lateral ankle instability surgery depends on proper phases of the rehabilitation period [170]. Although a supervised impairment-based program after chronic ankle instability was superior to control, followup in the included trials tended to be short and inconsistent, although the effect size exceeded the MCID and so likely would be identified as clinically important by patients [50].

Functional milestones: Only subjects with chronic ankle instability had reductions in self-reported function [4]. The increased symptomology associated with decreased ankle joint health further supports information demonstrating joint degeneration in young adults with chronic ankle instability [25].

Other Considerations: Symptomatic chronic lateral ankle instability could be successfully managed with this easy and effective surgical reconstruction method [6]. Ankle stability resumed with a high clinical success rate following a new arthroscopic Broström procedure [39]. Augmented direct anatomical repair and lateral tenodesis provide satisfying long-term outcomes in terms of subjective and objective parameters up to 15 years from surgery in patients with chronic ankle instability without leading to significant arthritic changes [66]. This case series showed increased stability of the ankle in clinical and functional outcomes following allograft tendon reconstruction of the anterior talofibular ligament and calcaneofibular Ligament [31]. Fourteen years post-procedure, the patient maintained a stable, painless ankle with no additional instability following salvage reconstruction using a tendon allograft [21]. One year after the procedure, roentgenograms showed stable ankles with a full range of motion [82]. The review identifies a clear deficiency in the literature pertaining to consistent, meaningful postoperative return to sport timeline following lateral ankle ligament repair [173]. She experienced a return to the same level of sports activities and reported no pain on either ankle following bilateral os trigonum fracture treatment [172]. An inability to complete jumping and landing tasks within 2 weeks of a first-time lateral ankle sprain and poorer dynamic postural control and lower self-reported function 6 months after a first-time lateral ankle sprain were predictive of eventual chronic ankle instability outcome [169]. Residual ankle symptoms were found in 33 per cent. of the patients, and persistent abnormal changes of the ankle were found in 60 per cent. following acute ankle sprains [15]. The prognosis for a simple inversion injury without visible instability is the same as that for a completely unstable ankle treated by primary ligament suture [171].

Key Evidence

• [L4] Chronic syndesmotic instability and chronic medial ankle instability are significantly associated with unsatisfactory outcomes in patients with chronic ankle instability. [1] (10.1016/j.arthro.2015.02.021)
• [L4] This paper summarizes a consensus on identifying which patients with chronic ankle instability may require surgery, the optimal surgical intervention, and the role of arthroscopic treatment based on available evidence. [2] (10.1016/j.otsr.2013.10.009)
• [L5] Chronic lateral ankle instability is frequently encountered in military service members; appropriate nonoperative treatment should be attempted initially, but surgical management is warranted when nonoperative treatment fails to prevent long-term sequelae. [3] (10.1016/j.csm.2014.06.011)
• [L3] Only subjects with chronic ankle instability had reductions in self-reported function. [4] (10.2519/jospt.2012.3923)
• [L2] This document is a protocol for a randomised controlled trial designed to determine the effects of MWM on anatomical and clinical characteristics of chronic ankle instability, including long-term effectiveness at 12 months. [5] (10.1186/s12891-019-2447-x)
• [L4] Symptomatic chronic lateral ankle instability could be successfully managed with this easy and effective surgical reconstruction method. [6] (10.1016/j.injury.2003.09.035)
• [L3] Combined treatment of chronic ankle instability and anterior ankle impingement produced satisfactory surgical outcomes in patients with CAI accompanied by anterior ankle impingement symptom. [8] (10.1186/s12891-018-2168-6)
• [L4] Arthroscopic diagnosis and treatment of intra-articular lesions associated with chronic lateral ankle instability is a safe and effective method. [9] (10.1177/0363546508319050)
• [L3] Subjects with chronic ankle instability show less variability in muscle activation patterns between test conditions. [10] (10.1177/0363546506294470)
• [L2] Although only fair-quality evidence exists in support of open operative treatment of chronic ankle instability, this systematic review helps reassure clinicians of their current practices. [11] (10.1136/jisakos-2018-000265)
• [L3] The clinical and radiologic outcomes of patients with chronic ankle instability improved after all-inside arthroscopic ATFL repair. [12] (10.1177/03635465211008097)
• [L4] Residual ankle symptoms were found in 33 per cent. of the patients, and persistent abnormal changes of the ankle were found in 60 per cent. [15] (10.2106/00004623-195537060-00011)
• [L5] [16] (10.5435/00124635-200810000-00006)
• [L3] Patients with chronic ankle instability demonstrate atrophy of intrinsic and extrinsic foot and ankle musculature accompanied by lower ankle strength. [17] (10.1177/2325967116653719)
• [L4] Ankle arthroscopy was performed more frequently in female patients and most commonly in patients younger than 50 years, with a significant increase in its use for lateral ankle instability management. [19] (10.1016/j.arthro.2015.01.020)
• [L2] Arthroscopy plays a crucial role in the definitive assessment of ligament lesions in patients with chronic ankle instability, supplying far more accurate information than any of the current imaging studies. [20] (10.1016/j.otsr.2018.09.008)
• [L4] Fourteen years post-procedure, the patient maintained a stable, painless ankle with no additional instability. [21] (10.1097/01.blo.0000092976.12414.b0)
• [L4] Ultrasound-guided ATFL repair with or without augmentation for chronic lateral ankle instability is safe and results in clinical improvement at 6 months. [22] (10.1016/j.jisako.2025.100386)
• [L3] The increased symptomology associated with decreased ankle joint health further supports information demonstrating joint degeneration in young adults with chronic ankle instability. [25] (10.1007/s00167-018-5163-4)
• [L2] The load–displacement ratio would be a reliable and promising approach for chronic ankle instability diagnosis. [27] (10.1186/s13018-022-03177-3)
• [L4] Preoperative ankle arthroscopy revealed an essential amount of information that would otherwise have been undetected, showing that abnormalities of different structures are involved in chronic ankle instability with no single causal entity. [29] (10.1177/03635465020300031601)
• [L1] The clinimetric qualities of the FAAM need to be further demonstrated in a specific population of patients with chronic ankle instability. [30] (10.1186/1471-2474-8-6)
• [L4] This case series showed increased stability of the ankle in clinical and functional outcomes. [31] (10.1186/s12891-017-1492-6)
• [L4] This survey reflected the heterogeneity of surgical practices in ankle instability and provided indications for areas of research in clinical situations with the least consensus. [32] (10.1177/2325967120s00009)
• [L4] Lateral ligament reconstruction with allograft represents a valid treatment option in patients with severe chronic lateral ankle instability, leading to satisfying outcomes and reduced joint morbidity. [33] (10.1007/s00402-013-1911-6)
• [L4] The final diagnosis of chronic instability of the anterior syndesmosis can be made during arthroscopy of the ankle. [34] (10.1186/1471-2474-12-212)
• [L4] Ankle stability resumed with a high clinical success rate. [39] (10.1186/s13018-023-03789-3)
• [L4] This arthroscopic classification of chronic ATFL lesions confirms the diagnostic role for arthroscopy in assessing the ligaments in patients with CAI and is helpful for determining the best surgical technique for stabilising the ankle. [42] (10.1016/j.otsr.2018.09.004)
• [L5] Operative procedures that only focus on part of the pathology should be approached with caution until assessment of a patient with ankle instability defines all deficiencies. [43] (10.2106/jbjs.21.00726)
• [L4] The literature would benefit greatly from the standardization of the definition of ankle instability treatment failure. [44] (10.1177/03635465231153165)
• [L2] A new comprehensive stress radiographic technique for diagnosis of chronic lateral ankle instability presented in this study might be a reliable and representable measurement tool to assess additional injury or instability of the subtalar joint. [45] (10.1007/s00167-016-4037-x)
• [L5] The number of mechanoreceptors was negatively correlated with ankle sensorimotor dysfunction. [46] (10.1177/03635465231217490)
• [L4] These findings are of clinical relevance because they provide a suitable minimally invasive method for the treatment of mild to moderate ankle instability. [47] (10.1007/s00167-020-06368-9)
• [L2] Two postoperative treatments differing by weightbearing status after modified Brostrom procedure for chronic lateral ankle instability showed good clinical results and similar outcomes in clinical and radiological outcomes. [48] (10.1016/j.arthro.2017.08.158)
• [L4] Chronic ankle instability with poor remnant ligament-tissue quality can be successfully treated by an arthroscopic all-inside repair and suture augmentation of the ligament. [49] (10.1007/s00167-018-5117-x)
• [L1] Although a supervised impairment-based program after chronic ankle instability was superior to control, followup in the included trials tended to be short and inconsistent, although the effect size exceeded the MCID and so likely would be identified as clinically important by patients. [50] (10.1097/01.blo.0000534691.24149.a2)
• [L4] [54] (10.1007/s00402-011-1421-3)
• [L4] Intra-articular pathological findings are observed in patients with anterolateral pain after an ankle sprain despite no demonstrable abnormal lateral laxity. [58] (10.1007/s00167-014-3454-y)
• [L4] Antero-lateral ankle impingement syndrome is closely linked to anterior talo-fibular ligament injury and, in some patients, to chronic ankle instability. [59] (10.1016/j.otsr.2017.09.004)
• [L3] Individuals with chronic ankle instability experience impaired proprioception compared to healthy individuals, while showing no notable differences in key muscle activation patterns. [62] (10.1186/s12891-025-09212-8)
• [L3] Patients with chronic ankle instability had longer electromechanical delay times in neutral but not when the ankle was placed in inversion. [64] (10.1007/s00167-016-4243-6)
• [L3] Arthroscopic ankle stabilisation repair and reconstruction techniques hold considerable promise but require further evaluation to better determine the indications of repair versus reconstruction and to obtain information on long-term outcomes. [65] (10.1016/j.otsr.2018.09.005)
• [L3] Augmented direct anatomical repair and lateral tenodesis provide satisfying long-term outcomes in terms of subjective and objective parameters up to 15 years from surgery in patients with chronic ankle instability without leading to significant arthritic changes. [66] (10.1007/s00167-018-5244-4)
• [L4] Ligament stabilization with arthroscopic procedures for individuals with chronic ankle instability and medial ankle OA yielded significant functional outcomes with high patient satisfaction, even without radiographic improvement. [67] (10.1007/s00167-020-05845-5)
• [L4] [68] (10.1007/s00167-017-4730-4)
• [L4] In this population and with this follow-up, the application of allogeneic tendons to treat malunited lateral malleolar avulsion fractures combined with chronic lateral ankle instability appeared safe and effective. [69] (10.1186/s12891-023-06390-1)
• [L2] Open and arthroscopic ATFL repairs equally achieved statistically significant improvement in functional outcome and effectively addressed functional and mechanical ankle instability. [72] (10.1177/23259671261417357)
• [L5] Arthroscopic treatment of ankle instability is emerging as the potential gold standard technique, offering the advantage of addressing both instability and associated intra-articular pathology in a single procedure with excellent results. [78] (10.1016/j.arthro.2020.10.043)
• [L4] The results confirm the interest of lateral ankle ligamentoplasty in the management of instability and protection against secondary osteoarthritis, and of precise lesion assessment (CT-scan/MRI) to adapt surgery to the ligamentary and associated lesions. [80] (10.1016/j.otsr.2010.04.004)
• [L4] Individuals with CAI demonstrate altered lower limb biomechanics, particularly greater ankle inversion angles and reduced ankle eversion moments, which may increase the risk of recurrent lateral ankle sprains. [86] (10.1186/s12891-026-09968-7)
• [L3] This supports the interpretation that the dynamic congruency of the joint, which is influenced by ligamentous integrity remains the main anatomical component in mechanical ankle instability. [87] (10.1186/s12891-025-09458-2)
• [L3] The study showed that the injured and uninjured sides of CAI demonstrate biomechanical characteristics associated with increased risk of ankle sprain, suggesting that management strategies should target both ankles. [90] (10.1177/23259671251394031)
• [L3] Alterations of kinematics in athletes with chronic ankle instability were found not only at the ankle but also at hip joints during the side-cutting movement. [100] (10.1007/s00167-015-3745-y)
• [L3] This was attested to reduced sagittal plane motions at the hip, knee and ankle joints, and reduced capacity of the stance limb to avail of its supporting base. [106] (10.1007/s00167-015-3744-z)
• [L4] The presence of a symptomatic peroneus quartus muscle should be considered in athletes with chronic ankle pain, swelling, and instability. [107] (10.1177/03635465010290032101)
• [L2] Both Ahlgren-Larsson and arthroscopic methods are safe and effective for chronic lateral ankle instability. [109] (10.1007/s00402-021-03799-y)
• [L3] Athletes with chronic ankle instability had a relatively inverted ankle, reduced muscle co-contraction, and a lower dynamic stiffness in the ankle joint during the landing phase of sports maneuvers, which may jeopardize the stability of the ankle. [112] (10.1177/0363546511406868)
• [L4] Increased fear of movement is associated with increased ankle joint position sense errors and postural sway in individuals with functional ankle instability. [114] (10.3390/ijerph19052792)
• [L4] Significant differences between players with and without CAI were seen in the support leg kinematics at flat-foot contact with the ground during the kicking cycle. [115] (10.1177/23259671221112966)
• [L3] The CAI, coper, and control groups displayed different ankle joint coupling patterns and coordination variability during a walking gait cycle. [117] (10.1177/23259671221139482)
• [L1] Reconstruction of the lateral ankle ligament is a relatively stable treatment for chronic ankle instability. [126] (10.1016/j.injury.2020.05.031)
• [Paper] Treatment of ankle instability in the future may need to account for alterations in brain activity in addition to deficits in the mechanical restraint of the joint provided by the articular, ligamentous, and muscular stabilizers. [129] (10.1097/corr.0000000000002991)
• [L3] The presence of CAI negatively affected ankle function and HRQoL in adolescent athletes. [131] (10.1177/2325967119900962)
• [L3] Valgus rearfoot alignment and poorer dynamic postural control were associated with chronic ankle instability among adolescent athletes. [133] (10.1177/23259671231202220)
• [L3] Athletes with chronic ankle instability demonstrated dynamic stability deficits, and the direction of the jump can affect dynamic postural stability in the sagittal and frontal planes. [138] (10.1186/s12891-025-09307-2)
• [L3] This study showed that MRI has excellent interobserver reliability (intraclass correlation coefficient, 0.915) for detecting ATFL injuries in patients in whom there is a clinical suspicion of chronic lateral ankle instability. [139] (10.1016/j.arthro.2015.02.024)
• [L5] [144] (10.1016/j.csm.2008.03.006)
• [L3] [145] (10.1177/0363546509351562)
• [L4] Surgical procedures for managing chronic lateral ankle instability include anatomic direct repair, anatomic reconstruction with an autograft or allograft, and arthroscopic repair. [151] (10.5435/jaaos-d-16-00623)
• [Paper] [163] (10.1016/j.injury.2020.03.054)
• [L3] MRI is a helpful tool for preoperative evaluation, but arthroscopy remains gold standard in the diagnosis of associated lesions in patients with CAI. [164] (10.1007/s00167-017-4567-x)
• [L1] [165] (10.1007/s00167-021-06610-y)
• [L3] Isolated injury to the superior fascicle identified on MRI may be useful when diagnosing patients presenting with symptoms of subtle instability without overt ankle laxity on clinical examination. [166] (10.1007/s00167-022-07275-x)
• [L3] [168] (10.1097/corr.0000000000003604)
• [L2] An inability to complete jumping and landing tasks within 2 weeks of a first-time lateral ankle sprain and poorer dynamic postural control and lower self-reported function 6 months after a first-time lateral ankle sprain were predictive of eventual chronic ankle instability outcome. [169] (10.1177/0363546516628870)
• [L5] The success of lateral ankle instability surgery also depends on proper phases of the rehabilitation period. [170] (10.1177/2325967124s00376)
• [L4] The prognosis for a simple inversion injury without visible instability is the same as that for a completely unstable ankle treated by primary ligament suture. [171] (10.1007/bf00932312)
• [L5] She experienced a return to the same level of sports activities and reported no pain on either ankle. [172] (10.5435/jaaosglobal-d-23-00237)
• [L4] The review identifies a clear deficiency in the literature pertaining to consistent, meaningful postoperative return to sport timeline following lateral ankle ligament repair. [173] (10.1136/jisakos-2016-000064)

See Also

• Lateral ligament reconstruction
• Ankle impingement
• Ankle osteoarthritis
• Ankle arthroscopy
• Ankle arthrodesis

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