Non-Achilles ankle tendinopathy

INTRODUCTION — Approximately 50 percent of sports-related injuries are related to overuse. Of injuries seen in running clinics, the majority are due to overuse with about half involving the lower leg [1]. Many such injuries involve a tendinopathy.

The clinical presentation and management of tendinopathies involving ankle tendons other than the Achilles is reviewed here. Achilles tendinopathy, as well as acute ankle injuries, are discussed separately. (See "Achilles tendinopathy and tendon rupture" and "Ankle sprain in adults: Evaluation and diagnosis" and "Ankle fractures in adults".)

TERMINOLOGY — Tendinopathy, or tendinosis, is a clinical syndrome that often follows an initial period of inflammation (tendonitis). Some clinicians mistakenly use the terms tendinopathy, tendinosis, and tendonitis interchangeably. The histopathology and treatment of tendinopathy differs from that of acute tendonitis. An overview of tendinopathy is provided separately. (See "Overview of overuse (persistent) tendinopathy".)

EPIDEMIOLOGY AND RISK FACTORS — Fifteen percent of overuse injuries affect the ankle, most commonly the Achilles, posterior tibialis, peroneus longus, and peroneus brevis tendons [1]. Tendinopathy can develop in both the athletic and sedentary patient but is uncommon in children. Extrinsic factors that can predispose to ankle tendinopathy include improper training, poor biomechanics (eg, running technique), and improper footwear. Intrinsic factors can include foot malalignment, leg length discrepancy, joint laxity, and obesity.

A number of medications have been associated with musculoskeletal injury, including nonsteroidal antiinflammatory drugs (NSAIDs) and statins. Although rare, fluoroquinolone use may be associated with tendinopathy and acute tendon rupture. The association of specific agents with tendon injury is discussed separately. (See "Nonselective NSAIDs: Overview of adverse effects", section on 'Healing of musculoskeletal injury' and "Statin muscle-related adverse events" and "Achilles tendinopathy and tendon rupture", section on 'Measures for patients on fluoroquinolones'.)

Comorbidities, such as rheumatoid or psoriatic arthritis, gout, diabetes mellitus, and spondyloarthropathy, may predispose to tendon injury. Observational studies suggest an association between tenosynovitis and rheumatoid factor [2], and although gout is typically identified with joint involvement, tendons are also often affected by monosodium urate crystal deposition [3]. (See "Clinical manifestations of rheumatoid arthritis" and "Clinical manifestations and diagnosis of psoriatic arthritis" and "Overview of the musculoskeletal complications of diabetes mellitus" and "Clinical manifestations and diagnosis of gout".)

LATERAL ANKLE TENDINOPATHY

Anatomy — The two main tendons that run along the lateral ankle are the peroneus (or fibularis) longus (picture 1) and peroneus (or fibularis) brevis (picture 2). The peroneal muscles that give rise to these tendons reside in the lateral compartment of the leg (figure 1 and picture 3 and figure 2).

The functions of the peroneal muscles and tendons include initiating plantarflexion, everting the foot at the ankle, and stabilizing subtalar motion. As an isolated muscle group, the peroneals' primary function is ankle eversion. However, as with many lower extremity muscles, function varies based on positioning. When the foot is off the ground, peroneal contraction contributes to plantarflexion of the ankle; when the foot is planted on the ground (during gait), peroneal contraction contributes to ankle eversion and dorsiflexion and stabilization of the subtalar joint.

The peroneal tendons enter a common synovial sheath approximately 4 cm proximal to the superior tip of the lateral malleolus. They course posterior to the lateral malleolus through a fibro-osseous tunnel called the retromalleolar groove, with the peroneus longus lying posterolateral to the peroneus brevis tendon. The tendons are secured in the retromalleolar groove by the superior peroneal retinaculum, which acts as the primary restraint to peroneal tendon subluxation.

Distal to the ankle, the tendon sheath bifurcates around the peroneal tubercle. The tendons then pass through the inferior peroneal retinaculum with the peroneus brevis inserting at the base of the fifth metatarsal, while the peroneus longus wraps around the cuboid and crosses the plantar surface ultimately inserting at the base of the first metatarsal and the lateral aspect of the medial cuneiform (picture 4) [4].

Two additional tendons may be present at the lateral ankle: the peroneus (or fibularis) tertius (picture 5) and peroneus (or fibularis) quartus. The peroneus tertius is present in 80 to 90 percent of the population and is unique to humans. It originates at the distal third of the fibula and inserts onto the dorsal aspect of the fifth metatarsal. The peroneus quartus is present in 15 to 20 percent of the population and arises from the peroneal muscles in the lateral leg. It can have a variety of attachments including the retrotrochlear eminence of the calcaneus, the cuboid, or the peroneus longus tendon. Although usually asymptomatic, the peroneus quartus may cause crowding in the retromalleolar groove and predispose to peroneus tendon dislocation or tear [5].

Clinical presentation and physical examination — Patients with tendinopathy of either the peroneal longus or brevis typically participate in one of any number of activities that place stress on the peroneal tendons, including running on banked or uneven surfaces (eg, trail running), sports that involve a lot of quick lateral movements and changes of direction (eg, soccer, American football, basketball), exercise drills involving such movements, and playing such sports or performing such drills on a slippery field. Skating in loose, poorly fitting skates also predisposes to peroneal tendon injuries.

Patients usually complain of several weeks of worsening lateral ankle pain that began without any known acute injury. Typically, symptoms are worse while standing or walking and the patient often walks with a slight limp. The patient may complain of a popping sensation along the lateral ankle. Tenderness is usually noted just posterior to the lateral malleolus and may be present along the course of the tendons distally. Swelling varies depending upon the severity of the condition. Pain is often reproducible with resisted active dorsiflexion and eversion of the ankle, which best isolates peroneal function [6]. With more severe tendinopathy, passive inversion or possibly eversion may produce pain. Observation may reveal a cavus foot (high arch), which observational studies suggest is associated with an increased risk of peroneal tendon disorders [4].

Observational studies and our clinical experience suggest that subluxation or dislocation of peroneal tendons predisposes them to tendinopathy [7,8]. Such subluxations and dislocations can be acute or chronic. Acute injuries are the result of acute trauma involving sudden, forceful ankle dorsiflexion, and patients often recall feeling a "pop" in the lateral ankle. Chronic cases are caused by underlying instability associated with recurrent ankle sprains. This chronic instability causes the peroneal retinaculum to become torn or incompetent, which in turn causes the peroneal tendons to move in and out of the retromalleolar groove. Over time, the extra strain placed on the tendons by weakened ankle ligaments and the loss of the retinaculum causes pathology ranging from tenosynovitis to tendon tears. Therefore, some patients with complaints suggesting peroneal tendinopathy will have signs of subluxation or dislocation, such as tendons that protrude from behind the lateral malleolus as the patient attempts to dorsiflex and evert their ankle against the examiner's resistance.

Imaging studies — In patients without a history of acute ankle trauma and a presentation suggesting peroneal (ie, fibularis) tendinopathy, we typically do not obtain plain radiographs but do perform an ultrasound (US) examination to assess the peroneal tendons as part of the standard workup in the clinic (image 1 and image 2 and image 3). In clinics without ready access to US, it is reasonable to diagnose peroneal tendinopathy on the basis of the history and clinical findings alone, foregoing imaging altogether. Imaging can be obtained subsequently if there is no improvement with conservative treatment. Ultrasound of the ankle is reviewed in detail separately. (See "Musculoskeletal ultrasound of the ankle and hindfoot".)

In patients who give a history of acute ankle injury, particularly patients with difficulty weight-bearing or focal bony tenderness or deformity, we typically obtain plain radiographs of the ankle, and possibly the foot depending upon the presentation. For patients with a likely ankle sprain, we refer to the Ottowa Ankle Rules to help determine the need for radiographs. The Rules are discussed separately. (See "Ankle sprain in adults: Evaluation and diagnosis", section on 'Diagnostic imaging'.)

When necessary, the initial imaging studies we obtain are weight-bearing plain radiographs, typically anteroposterior (AP), lateral, and mortise views of the ankle. These may reveal a fracture, osseous lesions associated with peroneal tendonitis, or other findings, such as an accessory bone (eg, os peroneum). Although useful for bony lesions, plain radiographs seldom provide useful information about soft tissue injury so we perform an US examination along with the radiographs during the initial evaluation. If US is not readily available, radiographs reveal no abnormalities that explain the patient's symptoms, and the history and examination suggest peroneal tendinopathy, it is reasonable to initiate conservative treatment based upon the presumptive clinical diagnosis and refer the patient for US evaluation or magnetic resonance imaging (MRI) subsequently if the patient does not improve.

Examination with US allows the examiner to identify many tendon tears and to compare tendon appearance in the affected and unaffected ankles [4,9-11]. Typical ultrasound findings of ankle tendinopathy include tendon thickening with hypoechoic swelling (image 4) and splits within the tendon fibers [12,13]. There may be increased blood flow to the tendon, which can be seen using the Doppler feature of the US machine and which may represent a healing response. If peroneal tendon subluxation or dislocation is suspected, US enables the clinician to see the tendons as they move in and out of the retromalleolar groove [14]. In some cases, the relative positions of the peroneus brevis and peroneus longus rapidly reverse as the tendons move out of the retromalleolar groove and over the lateral malleolus. This same type of sudden tendon movement (sometimes described as snapping) and shift in tendon position can also occur in a type of subluxation within the peroneal sheath in which the tendons do not leave the retromalleolar groove but continue to snap. This can only be seen with dynamic ultrasound [15,16]. (See "Musculoskeletal ultrasound of the ankle and hindfoot".)

Some observational studies suggest that US is more sensitive and as specific as MRI in identifying tendon abnormalities around the ankle. In a small prospective study using operative findings as the gold standard, US was reported to have a sensitivity of 100 percent, specificity of 90 percent and accuracy of 94 percent, while MRI was reported to have a sensitivity of 23 percent, specificity of 100 percent, and accuracy of 66 percent [17]. In addition, several studies report discrepancies between preoperative MRI reports and the lesions identified during surgery [7,18]. Nevertheless, MRI may be the best imaging study available to assess lateral ankle tendon injuries in some settings, particularly if local expertise with musculoskeletal US is limited [19,20]. The accuracy of MRI in centers where it is used frequently to assess the lateral ankle may be superior to that noted in some studies and newer technologies for MRI of the ankle are in development [21,22]. MRI may offer advantages when lateral ankle symptoms are less consistent with a typical tendinopathy. As an example, peroneal tendinopathy may be associated with osteochondral lesions (OCD) of the talus and such lesions are not identified as consistently using US as with MRI [23]. Thus, MRI may lead to a more accurate diagnosis when both tendons and the talar dome are injured.

As noted above, we rely on ultrasound and plain radiograph for the initial evaluation of lateral ankle injuries when tendinopathy is suspected. However, we use MRI (and possibly MR arthrograms) in patients with persistent lateral ankle pain that has failed to improve with appropriate treatment for tendinopathy, or whenever findings on the initial imaging studies are not consistent with our presumptive diagnosis.

Diagnosis — The diagnosis of peroneal tendinopathy can usually be made on the basis of the history and examination, without advanced imaging. Patients typically participate in an activity involving quick lateral movements that places stress on the peroneal tendons, and complain of several weeks of worsening lateral ankle pain that began without any known acute injury. Distance runners may note symptoms more quickly, sometimes even within a day of a long run performed on a sloped surface. This history plus findings of tenderness to palpation along the course of the peroneal tendons coupled with swelling and pain with resisted ankle dorsiflexion and eversion are highly suggestive of the diagnosis. Characteristic findings of tendinopathy on ultrasound examination (eg, tendon thickening with hypoechoic swelling, splits within the tendon fibers) confirm the diagnosis.

Differential diagnosis of lateral ankle tendinopathy — Lateral ankle pain is common and may be caused by a range of conditions, including the following:

●Ankle sprain or fracture – Acute trauma to the ankle is common and raises suspicion for a lateral ankle sprain or fracture, rather than tendinopathy. Most acute fractures are apparent on diagnostic imaging (typically a plain radiograph), while most ankle sprains that cause patients to seek medical attention occur from trauma and cause immediate symptoms or pain and instability, rather than worsening over weeks as is typical with peroneal tendinopathy. Symptoms from a chronic ankle injury, especially an ankle sprain, can mimic peroneal tendinopathy. Patients with a chronic ankle sprain typically complain of turning or "rolling" their ankle frequently, and manifest laxity with performance of the anterior drawer or talar tilt examination maneuvers, features absent with peroneal tendinopathy. (See "Ankle sprain in adults: Evaluation and diagnosis" and "Ankle fractures in adults".)

●Peroneal (fibularis) tendon dislocation or rupture – Trauma to the lateral ankle may cause dislocation or a tear of the peroneal tendon. Dislocation results from an incompetent or torn superior peroneal retinaculum, or possibly a shallow fibular groove. In addition to the history of acute trauma, swelling and ecchymosis are typically more extensive with such injuries, and these findings help to distinguish tendon tears and dislocations from peroneal tendinopathy. The Kleiger test can help to distinguish between a peroneal tendon subluxation and tendinopathy, and is performed by stabilizing the lower leg just above the ankle with one hand while the other hand dorsiflexes and externally rotates the ankle. Although this test is best known for evaluating "high" ankle sprains, it can also be used to evaluate possible peroneal tendon subluxation and dislocation. A positive test suggesting subluxation causes the tendon to bowstring over the lateral malleolus. Peroneal subluxation predisposes patients to developing tendinopathy. (See 'Clinical presentation and physical examination' above.)

●Stress fracture – Stress fractures of the proximal fifth metatarsal occur in participants in running, and sports involve sudden change of direction (cutting) and jumping. The patient (usually a young athlete) gives a history of a recent increase in activity volume or intensity and complains of lateral foot pain. Examination typically reveals tenderness directly over the proximal metatarsal, rather than over the tendons, and focal pain develops at the bone when the patient hops. (See "Proximal fifth metatarsal fractures", section on 'Stress fractures of proximal diaphysis: Zone 2 injury' and "Overview of stress fractures".)

●Os peroneum and os trigonum – The os peroneum is an accessory bone found in approximately 20 percent of the population that is situated within the substance of the peroneus longus tendon along the lateral foot (figure 3 and picture 6) [4]. It can become symptomatic and present in a manner similar to tendinopathy. Without imaging studies, it is difficult to distinguish between the two. The os trigonum is found in approximately 13 percent of the population and lies just posterior to the talus (figure 3 and image 5 and image 6). Patients with a symptomatic os trigonum have tenderness posterior to the lateral malleolus but not directly over the tendons. Also, the swelling seen in peroneal tendinopathy is absent and resisted dorsiflexion and eversion does not elicit pain. Often os trigone injuries become more painful during forceful plantarflexion. Both os peroneum and os trigonum can be evaluated with plain radiographs. (See "Ankle pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Os peroneum' and "Ankle pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Os trigonum syndrome (posterior ankle impingement)'.)

●Neuropathy – Pain around the lateral ankle may be caused by peroneal neuritis, peroneal nerve palsy, or lumbar radiculopathy. Neuropathic pain is often described as constant and burning or tingling, radiates along the course of the nerve, and is unaffected by ankle position or weightbearing. Focal tenderness at the tendon is absent. (See "Overview of lower extremity peripheral nerve syndromes", section on 'Fibular (peroneal) nerve' and "Acute lumbosacral radiculopathy: Etiology, clinical features, and diagnosis", section on 'L5 radiculopathy'.)

●Apophysitis of fifth metatarsal – Children and adolescents can develop apophysitis at the base of the fifth metatarsal where the peroneus brevis inserts. The child may walk with a limp, and typically the base of the fifth metatarsal is focally tender. If pain started after a traumatic injury, plain radiographs can differentiate between apophysitis and fracture. Ultrasound findings of apophysitis include an open apophysis and accumulation of fluid, noted by hypoechoic changes that are greater than the unaffected side. (See "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Iselin disease (fifth metatarsal traction apophysitis)'.)

●Cuboid subluxation – Subluxation of the cuboid (sometimes referred to as cuboid syndrome) can mimic peroneal (fibularis) tendinopathy and is difficult to diagnose [24,25]. It can occur as the result of an acute ankle inversion injury or as an overuse syndrome, which is common among professional ballet dancers (from dancing en pointe) [26,27]. Cuboid syndrome is hypothesized to be due to small disruptions in the calcaneocuboid ligament that allow the cuboid to slip from its normal, anatomic position. Imaging is generally normal and the diagnosis is made clinically.

In contrast to peroneal (fibularis) tendinopathy, focal tenderness over the cuboid is often present [24,25]. The condition typically presents similar to a lateral foot ligament sprain, with pain and tenderness localized to the cuboid and its calcaneal articulations proximally, and possibly the fourth and fifth metatarsals distally. Patients may describe minor foot trauma or feeling a small “pop” in the lateral midfoot. Other examination findings may include mild swelling and ecchymosis over the plantar cuboid surface. Pronounced swelling or tenderness suggest more severe injury. The midtarsal adduction test elicits pain. This test is performed by stabilizing the ankle and subtalar joint with one hand, while the other hand applies an adduction (or varus) force to the midfoot (picture 7).

Treatment is to manipulate the cuboid back into position [28,29]. This manipulation is performed with the patient prone and their knee flexed to about 70 to 90 degrees. The clinician then gradually places the patient's foot and ankle into maximal plantarflexion. As the soft tissues relax, the clinician applies pressure to the cuboid in a plantar to dorsal orientation. Theoretically, this manipulation is thought to realign the calcaneocuboid joint, but this theory has yet to be confirmed. The whip maneuver is also used to reposition a subluxed cuboid and is performed by having the athlete lie prone with their knee flexed to about 90 degrees and the ankle relaxed in neutral position. With the patient relaxed, the clinician grasps the foot and rapidly whips it up and down, moving rapidly between ankle dorsiflexion and plantarflexion until the cuboid pops back into place. The standard whip maneuver and a variation are shown in the accompanying video clips (movie 1 and movie 2). Placement of a lateral heel wedge or longitudinal arch strap (acutely taping is used) may be performed to try to maintain the position of the cuboid after manipulation.

●Osteochondral dissecans of the talus – Osteochondral dissecans (OCD) of the talus is uncommon and can be difficult to diagnose but should be considered in a young patient who presents with chronic ankle pain following an ankle inversion injury that fails to improve with standard treatment. Patients complain of diffuse ankle pain possibly associated with swelling, stiffness, and/or weakness. Examination may reveal tenderness along the anterolateral joint line of the ankle. Plain radiographs of the ankle sometimes reveal pathology (image 7) but may be normal. If suspicion is high and plain radiographs are unrevealing, an MRI is needed to make the diagnosis (image 8). Osteochondral fractures can sometimes be seen at the anterior lateral or medial corner of the talus during ultrasound of the ankle. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis".)

Treatment — The initial treatment for peroneal tendinopathy is standard conservative care, including relative rest. Eccentric strength exercises are essential for rehabilitation. The treatment of chronic tendinopathy is reviewed in detail separately, but issues of relevance to peroneal tendinopathy are discussed here. (See "Overview of the management of overuse (persistent) tendinopathy".)

In addition to standard conservative therapy, lateral heel wedges and ankle taping can help to reduce the stress placed on the peroneal tendons [6]. Standard taping is used as would be performed for an ankle sprain. Compression sleeves may provide additional support for some patients (picture 8).

Eccentric exercises are an essential part of treatment, and the accompanying table outlines these exercises (table 1 and picture 9). Note that the foot must be positioned properly in order for the eccentric stress to be placed primarily on the peroneal tendons (picture 10). This entails the ankle first descending so the foot is placed in an everted position. The everted position initiates firing of the peroneal muscles. Next, the eccentric phase of contraction is performed when elevating the heel, so we emphasize to our patients that they should perform this movement slowly, before lowering the heel below the level of the step to reset for the next repetition.

In addition to the rehabilitation protocol, the author uses a three-month trial of topical nitroglycerin patches; although, published evidence supporting this therapy is limited. (See "Overview of the management of overuse (persistent) tendinopathy", section on 'Topical nitroglycerin (glyceryl trinitrate)'.)

If conservative treatment, including full participation for six months in a well-designed rehabilitation program emphasizing eccentric exercise, is unsuccessful, patients may be referred to a surgeon with expertise managing foot and ankle pathology. However, although operative treatment of peroneal tendinopathy after failed conservative treatment leads to improved function in some patients [30], studies assessing the results of surgical management of tendinopathy are limited and outcomes are unpredictable [31]. Discrete mechanical problems are more amenable to surgical treatment. If peroneal tendon subluxation or dislocation, or a significant tendon tear, is diagnosed, the patient should be referred to foot and ankle surgeon for definitive treatment, as these conditions often require surgical repair, especially in high-demand individuals [32].

MEDIAL ANKLE TENDINOPATHY

Anatomy — Three tendons run alongside the medial ankle (figure 4 and figure 5): posterior tibialis (picture 11), flexor hallucis longus (picture 12), and flexor digitorum longus (picture 13). Most tendon problems at the medial ankle involve the posterior tibialis tendon, but sometimes problems develop in the flexor hallucis longus. Flexor digitorum tendinopathy is rare.

Located in the deep posterior compartment of the leg, the posterior tibialis muscle functions as a powerful dynamic stabilizer of the foot's longitudinal arch and the primary inverter of the foot [33,34]. The tendon passes posterior to the medial malleolus where it changes from a vertical to a horizontal direction. It is held in place behind the medial malleolus by the flexor retinaculum. The majority of the tendon inserts onto the navicular, but a second slip of tendon attaches to the plantar surfaces of the middle and lateral cuneiforms and the cuboid, as well as to the bases of the corresponding metatarsals.

The flexor hallucis longus muscle functions as the primary flexor of the great toe but also assists in ankle plantarflexion [34]. The muscle originates at the distal two-thirds of the posterior fibula and inserts at the base of the distal phalanx of the great toe. The flexor digitorum longus muscle flexes the lesser toes and seldom develops tendinopathy. It originates at the posterior three-fifths of the tibia and branches into four tendons, each of which inserts onto the base of the four lesser distal phalanges. The flexor digitorum longus is an accessory muscle found in 4 to 12 percent of cadaver specimens that may be associated with clinical symptoms [35].

Clinical presentation and physical examination — Medial ankle tendinopathy most often involves the posterior tibialis or flexor hallucis longus. In most cases of posterior tibialis tendinopathy, pain increases gradually over weeks and patients do not recall a traumatic event. Some patients may recall a twisting type of injury, such as stepping off a curb or stepping into a hole, and in such cases, the condition is often misdiagnosed as a medial ankle sprain. Women are more commonly affected than men and patients are often over the age of 40 [6].

Patients with posterior tibialis tendinopathy typically complain of pain around the posteromedial ankle. Swelling may be present along the course of the tendon, particularly several centimeters proximal to its insertion on the navicular. However, as the condition progresses, partial tearing of the tendon or avulsion from its insertion on the navicular can occur, and the longitudinal arch may drop resulting in a "flat foot" (pes planus). This collapse causes midfoot rotation and impingement of lateral structures. The patient may then complain of lateral ankle pain and a gradual "turning out" of the foot [33].

If posterior tibialis tendinopathy is suspected, the physical examination should include close inspection of the foot and ankle, looking in particular for a collapsed arch, midfoot rotation, and other structural differences between the affected and unaffected extremities, and an assessment of gait. One common finding is the "too many toes sign" (figure 6). When observing the affected foot from behind, the examiner will see more toes exposed on the lateral side of the involved foot [6]. In addition to pes planus (picture 14 and picture 15), the clinician may note hindfoot valgus (picture 16) or forefoot abduction. Excessive pronation may be seen due to weakness of the tendon.

As part of the examination, the patient can be asked to perform 10 successive heel raises. Incomplete inversion of the heel, difficulty or inability to raise the heel, or sensations of weakness or pain below or behind the medial malleolus while performing the test suggests posterior tibialis tendon dysfunction [33]. Patients with normal foot and ankle strength should be able to complete 5 to 10 single limb heel raises without difficulty. Particularly in patients with signs of more severe injury (eg, collapsed arch), the clinician should assess subtalar motion (movie 3). This is done by holding the ankle firmly in dorsiflexion and then passively inverting and everting the foot. It there is little or no motion, the subtalar joint is said to be locked and referral is needed (movie 4). (See 'Posterior tibialis tendinopathy' below.)

Posterior tibialis tendinopathy may be categorized by grade. Grade 1 injury is defined by pain and swelling of the tendon, but the patient is able to perform a single heel raise and there is no foot deformity. Grade 2 injury is defined by pain and swelling of the tendon, inability of the patient to perform a single-leg heel raise, and the presence of pes planus and forefoot abduction. Grade 3 injury includes all the criteria for a Grade 2 injury plus a fixed subtalar joint (movie 4).

Tendinopathy of the flexor hallucis longus (FHL) occurs most often in dancers, particularly classical ballet dancers but can develop in those who participate in activities requiring frequent, forceful plantarflexion of the ankle and foot or in jumping sports [36-38]. Runners, football (soccer) players, and basketball players may be affected. Pain from FHL tendinopathy usually develops insidiously along the posteromedial aspect of the ankle behind the malleolus. The examiner can elicit pain by resisting great toe flexion while the patient's foot is held in plantarflexion. Varying degrees of hallux rigidus may be present. If the tendon is ruptured, the patient will be unable to flex their great toe.

A number of less common conditions may contribute to FHL tendinopathy, including os trigonum syndrome [39]. In rare instances, patients with FHL tendinopathy develop an "intersection syndrome" of the foot (similar to the wrist) caused by friction between the FHL and the flexor digitorum tendons that leads to fibrosis and restricted movement [40]. Another rare cause of FHL tendinopathy is crowding and entrapment from an accessory flexor digitorum muscle. This muscle may attach to the FDL or FHL tendon or both and can inhibits free movement or restrict space leading to tarsal tunnel compression. While an accessory FDL is commonly noted in cadaver specimens, only rarely does it become large enough or attach in such a way as to trigger clinical symptoms. Magnetic resonance imaging (MRI) or ultrasound (US) can identify accessory muscles when symptoms are noted or an abnormal soft tissue mass is palpated in the space between the Achilles tendon and the medial retromalleolar space [41,42].

Imaging studies — Our approach to imaging patients whose presentation suggests medial ankle tendinopathy is identical to that described above for patients with suspected lateral ankle tendinopathy. (See 'Imaging studies' above.)

In patients without acute trauma, we typically do not obtain radiographs and use ultrasound to help assess tendon appearance and function. The following long-axis ultrasound images provide examples of normal and injured tendons (image 9 and image 10 and image 11); the following short-axis ultrasound images provide additional examples (image 12 and image 13). In patients who give a history of acute ankle injury, particularly patients with difficulty weight-bearing or focal bony tenderness or deformity, we typically obtain plain radiographs of the ankle, and possibly the foot. In patients with remote ankle trauma, a plain radiograph may demonstrate spurs or other bony changes impinging on the tarsal tunnel. For patients diagnosed initially with tendinopathy whose symptoms do not improve with conservative treatment, radiographs of the foot and ankle may be needed to rule out an os naviculare, an accessory bone that can become symptomatic, or advanced imaging studies may be needed for diagnosis [43]. Ultrasound of the ankle is reviewed in detail separately. (See "Musculoskeletal ultrasound of the ankle and hindfoot".)

MRI is more useful for identifying lesions of the posterior tibialis tendon and other posterior ankle pathology than it is for assessing the peroneal tendons and lateral ankle. One small observational study reported that both MRI and US demonstrated comparably good sensitivity and specificity for diagnosing posterior tibial tendinopathy [44]. In addition, MRI may have a specific role in individuals with significant posterior tibial dysfunction who have both tendinopathy and plantar calcaneonavicular (ie, spring) ligament tearing [45]. In patients who have posterior tibial tendinopathy in association with an accessory navicular, MRI may demonstrate bone edema or separation of the accessory navicular, suggesting that the extra ossicle is playing a significant role in the pathology [46].

Diagnosis — The diagnosis of posterior tibialis or flexor hallucis longus (FHL) tendinopathy can usually be made on the basis of the history and examination without advanced imaging. Posterior tibialis tendinopathy causes pain around the posteromedial ankle, while swelling may be present just proximal to the tendon insertion. Advanced tendinopathy can cause the tendon to tear or avulse, causing a collapsed foot arch and lateral foot pain. Difficulty or inability to perform a heel raise combined with pain below or behind the medial malleolus is suggestive. FHL tendinopathy occurs most often in dancers but can develop in those involved in activities requiring frequent, forceful plantarflexion of the ankle and foot or jumping. While there are occasional acute full or partial tears of the FHL, pain usually develops insidiously along the posteromedial aspect of the ankle behind the malleolus; examination reveals pain with resisted great toe flexion. Characteristic findings of tendinopathy on ultrasound examination (eg, tendon thickening with hypoechoic swelling, splits within the tendon fibers) confirm the diagnosis of either condition.

Differential diagnosis of medial ankle tendinopathy — The differential diagnosis for medial ankle tendinopathy includes the following:

●Ankle sprain or fracture – A history of acute trauma makes tendinopathy less likely and raises concern for a fracture, tendon tear, or ligament sprain. Injuries may include fracture of the medial malleolus and deltoid ligament sprain. The history combined with physical signs associated with trauma (eg, focal bony tenderness or deformity, ecchymosis) and appropriate imaging studies (plain radiograph in the case of suspected fracture; ultrasound or possibly MRI in the case of tendon injury) readily distinguish such injuries from tendinopathy in most cases. (See "Ankle sprain in adults: Evaluation and diagnosis" and "Ankle fractures in adults".)

Isolated deltoid ligament sprains are uncommon and are usually the result of acute trauma involving forced eversion of the foot and ankle. Tenderness to palpation along the ligament is common and there may be diffuse swelling of the medial ankle.

●Plantar fasciitis – FHL tendinopathy is frequently misdiagnosed as plantar fasciitis [37]. Both can cause medial foot and ankle pain. Plantar fasciitis is diagnosed clinically by tenderness to palpation at the calcaneal origin of the plantar fascia (medial calcaneal tubercle), and possibly pain with passive dorsiflexion of the toes, while FHL tendinopathy causes pain with resisted great toe flexion and sometimes swelling or tenderness to deep palpation behind the malleolus. (See "Plantar fasciitis".)

●Medial malleolus stress fracture – Like medial ankle tendinopathy, stress fractures of the medial malleolus typically cause medial ankle pain that develops insidiously over weeks. A new or more vigorous exercise regimen is a common cause. Unlike tendinopathy, tenderness is present directly over the medial malleolus, rather than along the tendon (although this distinction may be difficult to make in some cases), and the pain from a stress fracture does not increase with passive stretch or resisted contraction of the involved tendon. Plain radiographs of a medial malleolus stress fracture may be normal, but the fracture is associated with a high risk of nonunion and careful assessment, possibly involving advanced imaging, is needed. (See "Overview of stress fractures".)

●Accessory navicular (os naviculare) – The difference between a painful navicular prominence and a symptomatic accessory navicular (os naviculare) is difficult to diagnose clinically, but these accessory bones can be seen easily on plain radiographs [47]. They often present as pain that mimics posterior tibial tendinopathy since fibers of the posterior tibialis tendon attach to the accessory ossicle. Because of this, examination maneuvers that stress the posterior tibial tendon also cause pain in symptomatic accessory navicular syndromes. The key to making the diagnosis is to obtain radiograph studies when there is direct tenderness at the insertion of the posterior tibial tendon into the navicular, particularly if this insertion point looks more prominent than usual.

●Tarsal tunnel syndrome – Tarsal tunnel syndrome refers to tibial nerve compression in the region of the ankles as the nerve passes under the transverse tarsal ligament. Patients with tarsal tunnel syndrome typically complain of aching, burning, numbness, and/or tingling involving the sole of the foot, the distal foot, the toes, and occasionally the heel. In contrast to medial tendinopathy, tenderness along the flexor tendons is absent (unless tarsal tunnel compression occurs in association with posterior tibialis tendinopathy, which is uncommon), while the Tinel sign (tapping over the tibial nerve causes pain that radiates along the nerve into the plantar surface of the foot) and the Valleix sign (tapping over the nerve causes pain that radiates proximally along the nerve into the leg) may be positive [48]. (See "Overview of lower extremity peripheral nerve syndromes", section on 'Tarsal tunnel syndrome'.)

●Neuropathy – Medial plantar nerve entrapment presents with burning heel pain, aching in the arch, and decreased sensation in the plantar surface of the foot proximal to the great toe [49]. Low lumbar radiculopathy causes pain, numbness, tingling, and possibly weakness with foot or toe movements. Neuropathic pain from either mechanism radiates along the course of the nerve but is unaffected by ankle position or weightbearing. Tenderness at the posterior tibialis or FHL tendon is absent, and the ankle exam reveals full range of motion, no swelling, and no focal tenderness. (See "Overview of lower extremity peripheral nerve syndromes", section on 'Fibular (peroneal) nerve' and "Acute lumbosacral radiculopathy: Etiology, clinical features, and diagnosis", section on 'Clinical presentations'.)

Treatment

Posterior tibialis tendinopathy — Treatment of posterior tibialis tendinopathy is based upon the severity of tendon damage, which is generally divided into three grades of injury:

●Grade 1 injury – Grade 1 injury is defined by pain and swelling of the tendon, but the patient is able to perform a single heel raise and there is no foot deformity. Initial treatment consists of rest, analgesics (eg, acetaminophen or NSAIDs), and an arch support or medial heel wedge. Physical therapy for ankle strengthening and flexibility, with a focus on the posterior tibialis, is introduced as symptoms allow [33]. Eccentric strength exercises are an essential part of rehabilitation (table 2 and picture 17 and picture 18). The author uses topical nitroglycerin patches, although the evidence supporting this intervention is limited. If pain and swelling are severe, immobilization in a removable fracture boot for four to six weeks may be necessary, with the patient allowed to bear weight as tolerated. For milder cases, a lace-up ankle support or a compression sleeve can be used to stabilize the foot and reduce the degree of dynamic pronation and swelling.

●Grade 2 injury – Grade 2 injury is defined by pain and swelling of the tendon, inability of the patient to perform a single-leg heel raise, and the presence of pes planus and forefoot abduction. In contrast with Grade 3 injuries, the subtalar joint remains flexible and can be moved passively during examination (movie 3). Treatment is similar to that for Grade 1 injury, but a supportive custom foot orthosis may be necessary [33]. If there is no improvement after three to six months of conservative treatment, including properly performed physical therapy involving eccentric strength exercises, referral may be made to a foot and ankle surgeon.

●Grade 3 injury – Grade 3 injury includes all the criteria for a Grade 2 injury plus a fixed subtalar joint (movie 4). All Grade 3 injuries should be referred to a foot and ankle surgeon for definitive treatment. Many of these prove to be complete tendon ruptures.

Flexor hallucis longus tendinopathy — Most cases of flexor hallucis longus (FHL) tendinopathy respond well to conservative measures, including rest, soft tissue and joint mobilization, and a shoe implant (eg, orthotic). Surgical release of the FHL tendon may be performed in cases refractory to conservative care [50]. If tendon dysfunction is associated with an accessory FDL, resection of this muscle may also resolve the FHL tendinopathy [35]. A complete tear of the FHL warrants referral to a foot and ankle surgeon; severe FHL injuries can be career-ending for athletes [36].

ANTERIOR ANKLE TENDINOPATHY

Anatomy — The anterior ankle tendons (picture 4 and figure 7) are the anterior tibialis (picture 19), extensor hallucis longus (picture 20), and extensor digitorum longus (picture 21). Tendinopathy and other pathology occur most often in the anterior tibialis tendon. Injury to the extensor digitorum longus or extensor hallucis longus tendons is rare.

The anterior tibialis muscle originates along the proximal two-thirds of the lateral tibia and inserts onto the plantar aspect of the base of the first metatarsal and first cuneiform. The muscle functions as the main dorsiflexor of the foot but also plays a role in foot adduction and inversion.

Clinical presentation and physical exam — Tendinopathy of the anterior tibialis is typically a chronic overuse injury in patients over the age of 45 [6]. It is common in cyclists who do a lot of hill training, as this requires a lot of upward pull on the pedal strap or cleated cycling shoe. It is also seen in distance runners, particularly those who incorporate a lot of hill training, and hikers who make steep climbs, which places stress on the anterior tibialis both during forceful push-off on ascent and deceleration during descent. A heavy backpack further increases the stress placed on the anterior leg compartment muscles and tendons. Football (soccer) players and American football kickers, who must often dorsiflex their ankle against resistance but often begin their kicking movements with the ankle plantar-flexed are also susceptible to anterior tibialis tendinopathy.

Tendinopathy of the anterior tibialis typically presents with insidious pain and swelling along the course of the tendon. The patient may have difficulty walking. Resisted ankle dorsiflexion reproduces the pain and may reveal some weakness compared with the opposite foot and ankle. Rupture of the anterior tibialis tendon is uncommon in the absence of direct trauma or comorbidities affecting tendon function, and results in a foot drop and a "slapping gait" due to the loss of dorsiflexion [6].

Imaging studies — Our approach to imaging patients whose presentation suggests tendinopathy of the anterior tibialis is identical to that described above for patients with suspected lateral ankle tendinopathy. In patients without acute trauma, we typically do not obtain radiographs and use ultrasound to help assess tendon appearance and function (image 14). Ultrasound of the ankle is reviewed in detail separately. (See "Musculoskeletal ultrasound of the ankle and hindfoot".)

In patients who give a history of acute ankle injury, particularly patients with difficulty weight-bearing or focal bony tenderness or deformity, we typically obtain plain radiographs of the ankle, and possibly the foot. In difficult cases, advanced imaging may be useful [51]. (See 'Imaging studies' above.)

When obtained, plain radiographs of the ankle may reveal osteoarthritis or anterior bone spurs off the distal tibia or talus, which can impinge on the anterior tibialis tendon.

Diagnosis — The diagnosis of anterior tibialis tendinopathy can usually be made on the basis of the history and examination, without advanced imaging. Patients are often runners or soccer (football) players and typically complain of pain along the anterior ankle and possibly weakness. The examination is notable for tenderness, and possibly swelling and warmth in more severe cases, along the course of the tendon on the dorsum of the foot, while resisted ankle dorsiflexion exacerbates the pain and may reveal weakness compared to the unaffected side. Characteristic findings of tendinopathy on ultrasound examination (eg, tendon thickening with hypoechoic swelling, splits within the tendon fibers) confirm the diagnosis.

Differential diagnosis of anterior ankle tendinopathy — The differential diagnosis for anterior tibialis tendinopathy includes: tendon rupture, lumbar radiculopathy, peroneal nerve palsy, ankle arthritis, and gout.

●Osteoarthritis – Ankle arthritis presents with limited active and passive ankle motion, chronic joint pain that increases with activity, and possibly an effusion. The pain may worsen with resisted dorsiflexion of the foot, mimicking anterior tibialis tendinopathy. Plain radiographs of the ankle can show findings associated with osteoarthritis, such as joint space narrowing, osteophytes, sclerosis, and subchondral cyst formation (image 15). (See "Clinical manifestations and diagnosis of osteoarthritis".)

●Crystal Arthropathy (gout or pseudogout) – Crystal arthropathy presents with an acute onset of pain, swelling, and erythema, whereas tendinopathy is characterized by insidious pain, focal tenderness, and the absence of erythema. Joint aspiration, the gold standard for diagnosis, reveals monosodium urate or calcium pyrophosphate (CPPD) crystals. In addition, crystal arthropathies often develop despite minimal activity, and patients may have a personal or family history suggesting increased risk. Ultrasound examination often reveals findings suggestive of crystal arthropathy [52]. (See "Clinical manifestations and diagnosis of gout" and "Clinical manifestations and diagnosis of calcium pyrophosphate crystal deposition (CPPD) disease".)

●Neuropathy – Patients who present with a slapping gait but no history of trauma may have a peroneal nerve palsy or an L4 lumbar radiculopathy. Neuropathic pain from either mechanism radiates along the course of the nerve but is unaffected by ankle position. Focal tenderness at the anterior tibialis tendon is absent, and the ankle exam reveals full range of motion (with the exception of absent active dorsiflexion in patients with a slapping gait), no swelling, and no tenderness. (See "Overview of lower extremity peripheral nerve syndromes", section on 'Fibular (peroneal) nerve' and "Acute lumbosacral radiculopathy: Etiology, clinical features, and diagnosis", section on 'Clinical presentations'.)

●Tendon rupture – Rupture of the anterior tibialis tendon is uncommon. It presents with a "slapping gait," as the patient is unable to actively dorsiflex the ankle causing the foot to slap the ground with each step. Often the patient recalls an acute injury that coincides with the onset of symptoms and may have been associated with an audible "pop" in the ankle.

Treatment — The treatment of anterior tibialis tendinopathy is similar to that for other ankle tendinopathies, and is usually successful [6]. Initial care consists of ankle rest and in cases of more severe injury, including patients with difficulty ambulating or partial tendon tears, three to six weeks of immobilization in a walking boot (picture 22) or cast is often necessary. Patients are usually encouraged to remove the boot when not bearing weight in order to maintain ankle mobility by performing simple, gentle range-of-motion exercises. Once immobilization is no longer needed, physical therapy including eccentric strength exercises is performed. If complete tendon rupture is suspected (inability to dorsiflex ankle, slapping gait), consultation with a foot and ankle surgeon is required.

ADDITIONAL ULTRASOUND RESOURCES — Instructional videos demonstrating proper performance of the ultrasound examination of the ankle and related pathology can be found at the website of the American Medical Society for Sports Medicine: sports US ankle-foot pathology. Registration must be completed to access these videos, but no fee is required.

FOLLOW-UP AND RETURN TO WORK OR SPORT — Evidence and practice guidelines to inform how best to follow patients being treated for ankle tendinopathy are lacking. We see patients in the clinic every three to four weeks until they are able to return to their preinjury level of activity. For more severe injuries requiring immobilization as part of the initial treatment, we encourage patients to discontinue immobilization as soon as possible in order to minimize joint stiffness, muscle atrophy, and Achilles tendon tightness, in addition to other problems that may develop in the hips, low back, or knees from the imbalances created by a cast or walking boot. In most cases, we have patients use a compression ankle sleeve for support and to continue this for at least several weeks following the completion of treatment. We perform serial ultrasound examinations to monitor tendon healing throughout treatment. There is usually no need to repeat a plain radiograph or magnetic resonance imaging (MRI), assuming the patient is making progress with physical therapy and there is no new trauma.

Once the patient can demonstrate full, painless ankle range of motion and is able to perform activities of daily living without pain, we allow them to return to most occupations and for athletes to begin a gradual return to sport. Athletes may return to full, competitive sport once they have demonstrated the ability to perform functional movements at full speed with minimal or no pain. This timetable varies from four weeks to six months depending upon many factors, including the severity of the injury, patient comorbidities, the patient's baseline level of fitness, compliance with physical therapy, and the nature of the sport (sports involving extensive running and jumping require longer rehabilitation).

Decisions about returning to work must be made on a case-by-case basis depending upon the demands of the work (eg, desk job versus heavy labor), the severity of the injury, and the fitness of the patient. Patients whose work involves no stress on the ankle can often return to work immediately. For athletes and patients whose work involves heavy physical labor, knowledgeable allied health specialists, such as athletic trainers or physical therapists, can assist with such determinations. On average, patients with mild anterior tibialis tendinopathy return to work in three to four weeks, with moderate tendinopathy six to eight weeks, and with severe tendinopathy three months or possibly longer.

PREVENTION — There are no high quality studies demonstrating the relative effectiveness of strategies for preventing ankle tendinopathy. Eccentric strength exercise is effective treatment for many tendinopathies [53], and we counsel our patients to continue performing these exercises two to three times per week once they are symptom-free and have returned to full activity. Before permitting patients to resume full activity, we make certain they have achieved adequate strength and mobility in the affected ankle. In addition, we ask patients to consider carefully any activities that may have contributed to their tendinopathy, and to approach such activities cautiously. As an example, runners or cyclists who believe that hill intervals played a role in their condition should resume such training gradually and increase training volume in small increments. Many experts suggest increases in training volume of no more than 10 percent per week.

Gait analysis, including running gait, performed by a knowledgeable clinician may identify biomechanical flaws needing correction or conditions amenable to treatment with a foot orthosis. Active patients and athletes should be instructed about how to increase their training volume and intensity to avoid injury. Patients with comorbidities such as obesity and diabetes mellitus that increase their risk for tendon problems should be encouraged to manage these conditions properly and to increase their exercise volume more gradually.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues in muscle and tendon injury diagnosis and management" and "Society guideline links: Muscle and tendon injuries of the lower extremity (excluding Achilles)".)

SUMMARY AND RECOMMENDATIONS

●Lateral ankle tendinopathy

•Etiology and clinical presentation – Tendons most commonly involved include peroneal longus or peroneal brevis. Tendinopathy may be caused by any activity that stresses these tendons, including running on banked or uneven surfaces, sports involving quick lateral movements and changes of direction (eg, football [soccer], American football, basketball), and skating in loose or poorly fitting skates.

Patients usually complain of several weeks of worsening lateral ankle pain not associated with an acute injury. The patient may have a slight limp and complain of a popping sensation along the lateral ankle. Tenderness is usually noted just posterior to the lateral malleolus and may be present along the course of the tendons distally. Pain is often reproducible with resisted active dorsiflexion and eversion of the ankle. Subluxation or dislocation of peroneal tendons predisposes them to tendinopathy. (See 'Clinical presentation and physical examination' above.)

•Management – Treatment for peroneal tendinopathy consists of conservative care, including relative rest. Lateral heel wedges and ankle taping can help to reduce the stress placed on the tendons. Eccentric strength exercises are an essential part of physical therapy. A rehabilitation program is described in the text. (See 'Treatment' above.)

●Medial ankle tendinopathy

•Etiology and clinical presentation – Medial ankle tendinopathy most often involves the posterior tibialis or flexor hallucis longus (FHL). In most cases of posterior tibialis tendinopathy, pain increases gradually over weeks. Some patients may recall a mild ankle twisting injury, which may lead to misdiagnosis as a medial ankle sprain.

Patients typically complain of pain around the posteromedial ankle. Swelling may be present several centimeters proximal to the tendon insertion on the navicular. A common finding is the "too many toes sign" where more toes are exposed on the lateral side of the involved foot when observed from behind. Other examination findings include incomplete inversion of the heel and difficulty performing a heel raise.

As the condition progresses, partial tearing of the tendon or avulsion from its insertion can occur, and the longitudinal arch may drop, resulting in a "flat foot" (pes planus). This collapse causes midfoot rotation, leading to lateral ankle pain, a gradual "turning out" of the foot, and possibly excessive pronation. (See 'Clinical presentation and physical examination' above.)

•Management – Treatment of posterior tibialis tendinopathy depends upon the extent of injury. Mild and moderate injuries generally do well with conservative care, consisting of rest, structural support, and physical therapy, including eccentric strength exercises. Severe injuries involving a rigid subtalar joint should be referred to a surgeon. (See 'Posterior tibialis tendinopathy' above.)

FHL tendinopathy occurs most often in classical ballet dancers but can develop in participants in activities requiring frequent, forceful plantarflexion of the ankle and foot or in jumping sports. Pain usually develops insidiously along the posteromedial aspect of the ankle behind the malleolus. The examiner can elicit pain by resisting great toe flexion while the patient's foot is held in plantarflexion. If the tendon is ruptured, the patient will be unable to flex their great toe. Most cases of FHL tendinopathy respond well to conservative treatment; a complete tear warrants surgical referral. (See 'Clinical presentation and physical examination' above and 'Flexor hallucis longus tendinopathy' above.)

●Anterior ankle tendinopathy

•Etiology and clinical presentation – Tendinopathy of the anterior tibialis is typically a chronic overuse injury in patients over the age of 45. It is common in cyclists and runners who do hill training as well as football (soccer) players, and it can also occur in hikers who make steep climbs. The condition typically presents with insidious pain and swelling along the course of the tendon. The patient may have difficulty walking. Resisted ankle dorsiflexion reproduces the pain and may reveal some weakness compared with the opposite foot and ankle. (See 'Clinical presentation and physical exam' above.)

•Management – Conservative treatment, consisting of rest, structural support, and physical therapy, including eccentric strength exercises, is usually successful. (See 'Treatment' above.)

●Management common to all injuries

•Diagnostic imaging – In patients without a history of acute ankle trauma and a presentation suggesting ankle tendinopathy, we typically do not obtain plain radiographs but do perform an ultrasound (US) examination to assess the tendons likely to be involved. In clinics without ready access to US, it is reasonable to diagnose ankle tendinopathy on the basis of the history and clinical findings alone, foregoing imaging altogether. Imaging can be obtained subsequently if there is no improvement with conservative treatment. (See 'Imaging studies' above.)

•Differential diagnosis – The differential diagnosis for ankle tendinopathy is comprised primarily of other musculoskeletal, neurologic, and rheumatologic ailments, which are described in the text and organized by location. (See 'Differential diagnosis of lateral ankle tendinopathy' above and 'Differential diagnosis of medial ankle tendinopathy' above and 'Differential diagnosis of anterior ankle tendinopathy' above.)

•Follow-up care and return to activity – We see patients with ankle tendinopathy in the clinic every three to four weeks until they are able to resume their preinjury level of activity. Once a patient can demonstrate full, painless ankle motion and perform activities of daily living without pain, we allow them to return to most occupations and begin a gradual return to sport. Athletes may return to full competitive sport once they have demonstrated the ability to perform functional movements at full speed with minimal or no pain. (See 'Follow-up and return to work or sport' above and 'Prevention' above.)