Original Article

The Relationship Between Lateral Ankle Sprain and Ankle Tendinitis in Ballet Dancers

Stephanie Ritter, M.P.T., and Marjorie Moore, P.T., M.S.(kines.), Ph.D.

Abstract and ankle tendinitis in ballet dancers. attempt to compensate. Their overuse for The lateral ligament complex of the ankle Informal interviews were conducted with this static stabilizing function, as well as for is the most frequently injured structure physical therapists who specialize in treat- dynamic dance movements, then leads to in the body. Although most simple ankle ing ballet dancers, providing a clinical tendonitis. This knowledge may heighten sprains do not result in long-term disability, context for this report. An extensive review awareness of the potential for developing a significant number do not completely of the literature was conducted, includ- tendonitis following ankle sprains, and resolve, leading to residual symptoms that ing electronic databases, reference lists lead to better rehabilitation of the injured may persist for years. The most commonly from papers, and relevant reference texts. ballet dancer. reported symptoms, particularly among Numerous studies have investigated ankle athletes, include instability, re-injury, and sprains and residual complaints; nearly all allet dancers spend a pre- tendinitis. Ballet dancers are a combination report that lateral ankle sprains commonly ponderance of their time in of artist and high-performance athlete; lead to chronic ankle instability. Studies ex- extreme plantar flexion, par- consequently, they are subjected to the ploring ankle stability have demonstrated Bticularly females who are en pointe same types of injuries as other athletes, that the peroneal muscles play a crucial including lateral ankle sprains and their role in ankle stabilization; EMG studies (on toe). This position is potentially sequelae. Furthermore, ballet dancers confirm they are the first to contract during unstable, especially in ankles with perform in unusual positions such as en ankle inversion stress. The dancer’s need decreased ligamentous support follow- pointe, which places the ankle in extreme for exceptional ankle stabilization may ing a sprain. To compensate for this plantar flexion, requiring stabilization by lead to peroneal overuse and tendinitis. instability ballet dancers may overuse surrounding muscles. Dancers’ extraordi- Studies have linked peroneal pathology to their peroneal muscles. The result nary performance demands place them a history of ankle sprain, but there is no may be development of tendinitis in at risk for other ankle injuries as well, dance medicine literature linking peroneal these muscles. In fact, clinicians who including inflammation of several tendons, tendinitis to prior ankle sprains. A growing work with dancers report that this especially the peroneals. This report reviews body of literature confirms myriad connec- tendinitis is common in ballet danc- the relevant literature to characterize the tions between lateral ankle sprains, residual ers. Interestingly, studies exploring the scope of lateral ankle sprains and sequelae, instability, peroneal muscle increased ac- discuss the importance of the peroneal tivity, and tendinitis. It is our belief that relationship between this ubiquitous muscles in ankle stability, and explore a ankle sprains lead to instability, particular tendinitis and prior ankle sprains can- relationship between lateral ankle sprain en pointe, for which the peroneal muscles not be found in the dance medicine literature. The purpose of this paper is to Stephanie Ritter, M.P.T., was a student in the Master of Physical Therapy Program review the current literature to: 1. at the College of St. Catherine at the time this paper was written. Marjorie Moore, characterize the scope of lateral ankle P.T., M.S.(kines.), Ph.D., is an Associate Professor, College of St. Catherine, Minneapolis, Minnesota. sprains and their sequelae; 2. highlight the role that bony anatomy plays in Correspondence: Marjorie Moore, P.T., M.S.(kines.), Ph.D., College of St. Catherine, reduced ankle stability when ballet 601 25th Avenue South, Minneapolis, Minnesota 55454; [email protected]. dancers are plantar flexed en pointe; Versions of this article were presented as posters at the Minneapolis chapter of the 3. discuss the importance of the pe- American Physical Therapy Association, Brooklyn Park, Minnesota, April 2005; roneal muscles in ankle stability; and and the International Association for Dance Medicine and Science, Stockholm, 4. explore the evidence for a relation- Sweden, November 2005; and was published in the IADMS Annual Conference ship between lateral ankle sprain and Proceedings, 2005. peroneal tendinitis. 23 24 Volume 12, Number 1, 2008 • Journal of Dance Medicine & Science

We hypothesized that there may Lateral ankle sprains are also the are often complex, involving multiple be a direct link between a history of most common injury in sports, con- structures; therefore, “ankle sprain lateral ankle sprain and subsequent stituting 38% to 45% of all injuries syndrome” may be a more appropri- development of peroneal tendinitis in athletic populations.2,7,8 Most stud- ate descriptor.7 Furthermore, previous so commonly seen in ballet dancers. ies agree that the lateral ligamentous literature has inadequately described This clinical relationship may also be complex of the ankle is the most fre- this multi-component involvement. present in other types of dance, but quently injured structure in the body.2,5 The result may be suboptimal care, we believe it will be stronger in ballet Furthermore, it has been reported that incomplete healing, and, ultimately, dancers due to their more precarious ankle injuries account for 25% of all persistent residual symptoms. ankle positions over a smaller base of time-loss injuries in sports involving support in pointe shoes. In addition running and jumping.4,11,12 Residual Symptoms Following to this increased need for lateral ankle Lateral Ankle Sprains stabilization, ballet dancers may also Sprained Ankle Syndrome Although most acute ankle sprains overuse the peroneals to achieve an A sprain is a tear of one or more do not lead to long-term disability, a aesthetically everted foot. ligaments at a joint (Fig. 1). An significant number do not completely To provide a clinical context for this ankle sprain or “twisted ankle” is often resolve, leading to residual symptoms report, informal interviews were con- thought of as a relatively simple injury that may persist for years.14 Symptoms ducted with two local physical therapists involving trauma to only the ankle liga- widely reported in the literature in- who specialize in treating ballet dancers.1 ments.7 However, Fallat and colleagues clude recurrent pain and swelling, While treating dancers with ankle ten- proposed that these injuries are actually functional and mechanical instability, donitis these therapists had noted a fre- more complicated, frequently involv- recurrent re-injury, and tendinitis.5 quent history of ankle sprain. Given this ing injury to additional surrounding Among the general medical clinic anecdotal information, we conducted an structures, such as the joint capsule.7 population up to 40% of patients extensive review of the literature to sup- Indeed, in recent studies of the char- experience these residual symptoms port the hypothesis that there is a direct acteristics of acute ankle sprains the after sprains,5,9,10,15,16 some even ten link between the two clinical conditions. investigators confirmed the presence years later.14 Chronic instability is First, several electronic databases were of concomitant soft tissue injuries to the most common complaint, and searched, including CINAHL, Medline, multiple structures surrounding the symptoms can be severe enough to Infotrac, PubMed, and Rehabilitation ankle.7,13 This finding was true in a limit the patient’s lifestyle.9 Despite and Physical Medicine. Then, further ci- majority of 639 cases7 and in all 61 efforts to rehabilitate these injuries, tations were identified from the reference cases13 examined surgically. Moreover, the recurrent re-injury rate for ath- sections of the papers retrieved. Finally, the investigators encountered tendini- letes has been reported to be as high relevant anatomy and kinesiology refer- tis of the peroneal tendons in 15.2%7 as 80%.12,16-19 ence texts were consulted. to 77%13 of these patients with ankle sprains. They noted that incidence of Lateral Ankle Sprains and Epidemiology of Lateral Ankle involvement of the peroneals had not Sequelae in Ballet Dancers Sprains previously been documented.7 It was Dance has long been understood to More than 20 years ago studies concluded that acute ankle injuries be an art form requiring tremendous identified ankle sprains as the most common injury treated in physi- cians’ offices and emergency rooms.2-4 Since then, research literature has consistently reported that the ankle continues to be the most frequently injured joint in the body. Fully 85% of those ankle injuries are sprains, and 85% of sprains occur to the lateral ligamentous complex,5 result- ing from the combined motions of plantar flexion and inversion.5-8 In fact, it is estimated that each day one ankle inversion sprain occurs for every 10,000 people, totaling 23,000 to 27,000 injuries per day in the Figure 1 Ankle sprain. Inversion sprain with tearing of lateral ankle ligaments. (Re- U.S. and accounting for up to 10% printed from: Peterson L, Renstrom P. Sports Injuries: Their Prevention & Treatment. of all visits to hospital emergency Chicago: Year Book Medical Pub. Inc., p. 344, lower fig., 1986, with permission from 7-9 rooms. Elsevier.) Journal of Dance Medicine & Science • Volume 12, Number 1, 2008 25 discipline. More recently, the medical such as age, gender, training, or The two long bones of the lower leg community has come to recognize the even range of motion could be used are known as the “crura” or “pillars” extraordinary athletic skill dancers to predict future injuries following of the leg. Hence, the ankle joint is must possess. In fact, research exam- ankle sprain. They did find that ankle also known as the talo-crural joint, ining physical performance profiles sprain and tendinitis about the ankle between the talus and the two crura. compares dancers to the most elite (including peroneal tendinitis) were Kinesiologically, it is a modified hinge athletes in competitive sports.19 the two most commonly recorded joint, with one degree of freedom in Dancers are often subjected to the new injuries. Furthermore, these the sagittal plane. Its normal motions same types of injuries as other ath- investigators concluded that history consist of dorsiflexion (ankle flexion letes.6 It is not surprising, then, that of previous injury, especially ankle or “flexed foot” in dance parlance) the most common acute injury found sprain, was the only factor found to and plantar flexion (ankle extension among ballet dancers is lateral ankle be statistically significant in predicting or “pointed foot” in dance parlance). sprain.6,19-21 Moreover, many authors further injury. They did not, however, Normal range of dorsiflexion is 0° emphasize that, like other athletes, expand upon specific mechanisms of to 20° from anatomical position. ballet dancers are likely to experience injury nor hypothesize about the link Normal range of plantar flexion is 0° complications following sprains, between history of ankle injury and to 50° from anatomical position.28-30 including residual instability, pain, subsequent injuries in dancers. Verha- However, plantar flexion range may swelling, muscle weakness, muscle gen has remarked upon the number be considerably increased in ballet imbalances, and tendinitis.5,6,20-22 of studies investigating residual ankle dancers (average 113°).31 Clinicians who work with dancers complaints over the years and noted Constraints on excessive move- point out that ballet dancers’ rigorous that an explanation for these pervasive ments at the ankle joint involve both training and exceptional performance symptoms still cannot be found in the static and dynamic joint components. circumstances also expose them to literature.10 Most investigators simply The joint is first protected by unique unique injuries. The most common categorize tendinitis as an overuse bony anatomy that provides varying of these include inflammation of sev- injury.6,19-21,27 Verhagen concluded amounts of stability depending on eral tendons around the ankle, most that future research should focus on the position of the ankle. Next, the notably flexor hallucis longus, Achil- the cause, treatment, and prevention capsule and ligamentous structures les, and peroneal tendons.22,23 In fact, of these residual complaints. stabilize the joint, guide motion, and references to “dancer’s tendinitis” can provide proprioceptive input. Finally, be found dating back over 20 years. Ankle Bony Anatomy and tendons crossing the joint connect to Hamilton, for example, asserts that Biomechanics of Ankle Stability muscles that contract actively to move “tendinitis about the ankle joint is The ankle joint controls movements the joint, and reflexively to protect the common in classical ballet dancers.”24 of the foot in relation to the lower leg. joint.12,29,32 Hardaker agrees,19 and Sammarco It also controls placement of the body The distal ends of the lower leg states that peroneal tendinitis is “com- over the foot during weight bearing on bones, the tibia and fibula, form the mon to all dancers.”25 the foot. Anatomically, the ankle con- shape of an inverted “U,” and grip What is perhaps more interesting sists of three bones: the talus (upper the wedge-shaped dome of the foot’s is what is not found in the literature, bone of the foot), the tibia (weight- talus bone, forming a tight mortise namely an explanation for this ubiqui- bearing “shin” bone), and the fibula and providing good bony stability tous tendinitis. While Hamilton21 and (non-weight-bearing lower leg bone). (Fig. 2A and B). However, the dome others19,23,25 have noted that tendinitis is one of the “miscellaneous problems following ankle sprains,” none of these investigators elaborates upon potential risk factors. In a more recent report, Milan reviewed ballet injury preva- lence and mechanisms of injury.26 He noted that peroneal tendinitis is reportedly the third most common injury about the ankle, but he did not discuss specific causative factors. Weisler and associates did explore A B C relationships between previous lower Figure 2 A extremity injuries and new injuries Bones of ankle (mortise) joint. , Ankle (anterior view) bones separated to show talus dome. B, Mortise joint model. C, Talus dome (superior view). Note that the sustained by dancers over the course 22 talus dome is wider anteriorly (in full dorsiflexion), but narrower posteriorly (in plantar of one year. Interestingly, they found flexion). (Reprinted from: Neumann D. Kinesiology of the Musculo-Skeletal System. St. no evidence to suggest that factors Louis: Mosby, pp. 484 and 488, 2002, with permission from Elsevier.) 26 Volume 12, Number 1, 2008 • Journal of Dance Medicine & Science of the talus is approximately 5 mm ligament (PTFL).8 The names of its synovial lining), surrounding wider anteriorly than posteriorly (Fig. these ligaments indicate their bony ligaments, and associated nerves and 2C).29 In ankle dorsiflexion the wide attachments. Each ligament originates vessels. Sprains are clinically graded anterior portion of the talus becomes on the tip of the lateral malleolus from I (least severe) to III (most wedged tightly between the two lower (the distal end of the fibula bone), severe), according to the extent of leg bones. Thus, the ankle is “locked” then fans out to attach to the talus ligament tearing and the amount of (minimal medio-lateral talar tilt is or calcaneus bones of the foot. These joint stability that is lost. allowed) and extremely stable when three ligaments may be palpated just There are two kinds of ankle the foot is dorsiflexed. In contrast, anterior, inferior, and posterior to the sprains: inversion and eversion. The in plantar flexion this wedge effect is malleolus, and are tender following most common type involves the lost. The narrow posterior end of the an ankle sprain. For further details of motion of inversion, or turning the talus slides between the distal tibia and their individual anatomy see a thor- foot sole inward, usually (in dancers) fibula, allowing a looser fit. Thus, the ough anatomy text.33-35 when landing from a jump.6 This ankle is “unlocked” (more talar tilt is Because of their various orienta- motion puts excessive stress on the allowed) and loses some of its bony tions at the ankle, the three lateral lateral ligaments of the ankle, pos- stability when plantar flexed.28 The ligaments stabilize the ankle in differ- sibly resulting in tears. This type is ankle must then rely on ligamentous ent positions. All three ligaments resist more common because the distal tip and musculotendinous support. As ankle inversion. The ATFL is taut in of the tibia (the medial malleolus) plantar flexion increases and bony plantar flexion, so it is the most com- does not extend as far distally. Thus stability decreases these soft tissues monly injured ligament.8 For further it provides a buttress against only have higher demands placed on them information about the biomechanics part of the medial side of the talus, and are more susceptible to injury. of each ligament see a kinesiology potentially allowing the talus to tilt text.36,37 under it. We will focus on this type Lateral Ligaments: Their Role in of sprain. The other kind involves the Ankle Stability Lateral Ankle Sprain Types opposite motion, eversion, or tilting The ankle’s lateral ligament complex A sprain is a tear (partial or complete) the foot sole laterally. This motion (Fig. 3) is composed of three liga- of a joint. (In contrast, a torn muscle puts excessive stress on the medial ments: anterior talo-fibular ligament or tendon is called a strain.) The ligaments of the ankle. It is less com- (ATFL), calcaneo-fibular ligament structures that are injured include mon because the lateral malleolus of (CFL), and posterior talo-fibular the joint capsule (fibrous sleeve and the fibula extends farther distally,

Figure 3 Lateral ligaments of the ankle. The three major sta- bilizing ligaments are the 1. anterior talo-fibular ligament, 2. posterior talo-fibular ligament, and 3. calcaneo-fibular ligament. (Modified from: Magee D. Orthopedic Physical Assessment (4th ed). Philadelphia: WB Saunders, p. 766, fig. 13-1B, 2002, with permission from Elsevier.)

Figure 4 Peroneal muscles. The tendons of the three peroneal (fibularis) muscles that stabilize the lateral ankle. (Modified from: Magee D. Orthopedic Physical Assessment (4th ed). Philadelphia: WB Saunders, p. 779, 2002, with permission from Elsevier.) Journal of Dance Medicine & Science • Volume 12, Number 1, 2008 27 providing a good buttress to the of the fifth metatarsal. In contrast, Thus, the peroneus muscles are lateral side of the talus, preventing the longer tendon of the peroneus vital to effective ankle function. They it from tilting in that direction. longus turns under the lateral border provide major support to the arches of of the foot at the cuboid bone and the foot, adjust the foot in relation to Lateral Ankle Tendon Anatomy: travels medially across the sole of the sloped stages, and control placement The Peroneals foot, under the plantar arch, to insert of the body over the foot.41 They work The muscles acting upon the ankle upon the plantar aspect of the medial synergistically with other muscles joint originate on the tibia and fibula cuneiform and base of the first meta- to provide medio-lateral stability to bones. No muscles attach to the talus; tarsal.28 Therefore, the peroneus brevis the ankle, midfoot, and first ray. The instead, they cross the ankle (both the helps to support the low lateral plantar peroneals are exceedingly important talo-crural and sub-talar joints) to arch and the peroneus longus helps in absorption of stress at the ankle, insert more distally on the foot.28 The to support the higher medial plantar providing support and preventing most important muscles that prevent arch. Along their paths both muscles injury to the lateral ligaments. Finally, inversion ankle sprains are the two pass behind the lateral malleolus, when static ankle stabilizers (such as muscles located on the lateral side helping to reinforce the lateral ankle. ligaments) are compromised by injury, of the lower leg: the peroneus longus These muscular stabilizing functions the peroneals function as dynamic and peroneus brevis. Their tendons are even more critical in an unstable stabilizers.11,28,41,42 pass along the lateral ankle (Fig. 4). ankle after a sprain. (Note that these muscles recently have The two primary actions of the Role of Peroneal Muscles in the been renamed “fibularis longus” and peroneal muscles are foot eversion Unstable Ankle “fibularis brevis.”38,39 Their accom- and plantar flexion. Eversion turns The role of the peroneal muscles in the panying tendons, retinacula, nerves the foot sole out laterally. This motion unstable ankle has been controversial. and vessels have also been similarly occurs primarily at the sub-talar joint Many studies exploring evertor mus- renamed. However, throughout this (between the talus and calcaneus).36,37 cle function in the unstable ankle have article the older terms have been re- Plantar flexion occurs at the talo-cru- been published recently. The peroneal tained in order to facilitate reference ral joint, pulling the sole of the foot muscles play a role in protecting a to the cited literature.) The fibers of downward, so that the foot dorsum vulnerable joint against further injury; the peroneus longus muscle originate moves away from the shin (“pointing” however, the extent to which these from the fibula head and proximal the foot, in dance parlance). muscles are able to provide dynamic two-thirds of its shaft and from the stability remains unclear. intermuscular septum. The peroneus Role of the Peroneal Muscles in Some researchers have examined brevis muscle originates just inferior Ankle Stability post-injury muscle strength, suggest- to the longus, from the distal two- In addition to the above voluntary ing that residual symptoms in the thirds of the fibula and intermuscular ankle movement function, these ankle are associated with weakness septum. The distal tendons of both peroneal muscles are also activat- of the peroneal muscles following muscles pass behind the lateral mal- ed reflexly, during excessive ankle sprains16,43,44; other investigators have leolus bony prominence (“outside movements, to protect the ankle since refuted that claim.11,45,46 In ankle bone”). Thus, they are behind from injury. When structures of the fact, recent studies have found that the ankle joint axis, which allows ankle are abnormally stretched, sen- the evertor muscles are often stron- them to perform plantar flexion. The sory receptors (proprioceptors) are ger than the invertors following a tendons are tightly anchored in place stimulated. This signal elicits spinal sprain.47-49 It has been suggested that by two connective tissue bands, the reflexes that cause muscles to fire this increased strength represents an superior and inferior peroneal reti- (contract) and stabilize the joints.40 adaptive response by the body (given naculae. Passing under these bands, Electromyographic (EMG) studies sufficient rehabilitation time), in an the tendons are encased in a synovial show that the peroneal muscles are effort to protect a vulnerable ankle.11 tendon sheath, or “tunnel.” It is here the first ones activated in response to Furthermore, it has been demon- that symptoms of peroneal tendinitis unintended ankle inversion.32 These strated that as inversion increases are commonly felt. muscles must then be strong enough (vulnerable positioning for an ankle Although the origins (proximal to counteract this unexpected inver- lacking ligamentous stability) the pe- attachments) of the two peroneal sion motion. Otherwise, inversion roneal muscles progressively contract muscles are nearby one another, they continues and the tensile stress of more forcefully.17 insert in very different locations distal- the resisting lateral ligaments may be Many researchers have proposed ly on the foot.33-35 The tendons diverge exceeded, leading to a sprain injury. It that peroneal muscle reflex response upon emerging from the tunnel. The has been demonstrated that weakness time is a more important factor than short tendon of the peroneus brevis or paralysis of the peroneal muscles strength in providing dynamic control proceeds directly along the lateral bor- leaves the ankle joint unstable and at of ankle stability. Again, the research der of the foot, to insert on the base risk for lateral ankle sprain.4,11,28,29 findings have been equivocal. Some 28 Volume 12, Number 1, 2008 • Journal of Dance Medicine & Science investigators found significantly are the best protection against further delayed peroneal reaction time in re- ankle injury.5 sponse to unexpected ankle inversion in subjects with unstable ankles.50-54 Tendinitis Conversely, other investigators ob- Tendons are cords of connective tis- served no significant differences in sue that link muscle to bone. Forces response times between stable and produced by contracting muscles are unstable ankles.39,48,55-57 Based on these transmitted through tendon tissue to and other reports, many researchers act upon a bone to produce move- have concluded that the peroneal re- ment. The structure of tendons is de- sponse is too slow to act as a dynamic signed specifically to withstand these protector of the ankle joint during tensile (tension) forces, but tendon sudden inversion stress.32 structure can be damaged in response Vaes and colleagues reached a to excessive tension, compression, different conclusion.54 They noted and friction stressors.58 The result that previous studies measured EMG may be an acute tendon injury called response of peroneal muscles to su- tendinitis, an inflammatory response pination and inversion used tilting in a tendon or its surrounding sheath trap-door mechanisms that started (in contrast, chronic tendon injury is with the ankle in a neutral ankle posi- tendinosis, or a non-inflammatory de- tion (0°) and did not exceed changes generative pathology of the tendon). of 30° to 35° of plantar flexion. Yet, Signs and symptoms of tendinitis are Figure 5 Foot skeleton in en pointe posi- normal range of plantar flexion is 0° localized pain, swelling, tenderness, tion. Tibia and fibula bones of lower leg to 50°. Consequently, in their own and crepitus (grating sensation). Spe- are unlabeled. Foot bones: T = talus, CAL study they decided to measure muscle cific mechanisms of injury to tendon = calcaneus, C = cuboid, N = navicular, response time in a more plantar flexed may include: CUN = cuneiform, MT = metatarsal, PP position. Peroneal response time was • Movement patterns performed = proximal phalanx, DP = distal phalanx, S = sesamoid. (Reprinted from: Atlas of studied by starting with the ankle repetitively which do not allow Human Anatomy, Spalteholz & Spanner, plantar flexed to 40° and then tilting sufficient time for tissue repair, Amsterdam, Netherlands: Sheltema & into supination. At this increased resulting in cumulative micro- Holkema, p. 401, 1967.) range of motion the peroneal muscles trauma; did initiate a motor response fast • A high magnitude (or high enough to decelerate the supination velocity) single stressor event, Tendinitis in Ballet Dancers stress, possibly limiting the impact producing tissue injury which is As previously noted, all athletes are on surrounding ligaments and other then sustained by normal daily at risk for lateral ankle sprains and soft tissues, thereby preventing injury. activities; the residual symptoms that may fol- Thus, the investigators concluded that • Uneven ground, requiring sudden low. The extraordinary performance the peroneal muscles respond more adaptation of the foot for walk- demands that ballet dancers place quickly to inversion stress when the ing; and on their ankles, including extreme ankle is already at increased ranges of • Shoes and their ribbons that range of motion, may make them plantar flexion. They demonstrated impose compression or friction particularly vulnerable. In fact, a bal- that there is sufficient time for these upon a tendon.58 let dancer must obtain at least 90° of muscles to restrain supination in a Most investigators note that the ma- plantar flexion in the foot and ankle plantar flexed ankle and thereby con- jority of tendon injuries are the result complex—enough to extend the axis tribute to ankle stability. of repetitive movements—that is, of the leg through the metatarsals to Several investigators have noted overuse.6,19-21 the floor—in order to achieve the that, despite the continuing ques- Peroneal tendinitis is a small subset relevé positions of demi-pointe and tions regarding how quickly and of all tendinitis problems about the en pointe (Fig. 5).21 This plantar forcefully the peroneal muscles are ankle. Achilles tendinitis is much flexed position is fundamental to able to respond to sudden stressors, more common, at 6.5% to 11% of ballet, as dancers spend much of there is widespread agreement that all lower extremity injuries in ath- their time in relevé.25 This position pre-planned, voluntary evertor muscle letes. Peroneal tendinitis is relatively requires exceptional range of motion, activity does indeed protect the joint uncommon, at about 1.5% in this stability, proprioception, and balance in the absence of static stabilizers (as in population. Female ballet dancers control. the ankle with injured ligaments).17,32 also have a unique predisposition to Ballet dancers are also at risk for Furthermore, they argue that fully tendinitis of the flexor hallucis longus tendinitis because of their rigorous activated and strong peroneal muscles due to overuse in pointe work.19,59-61 training and performance schedules. Journal of Dance Medicine & Science • Volume 12, Number 1, 2008 29

They are subjected daily to the repeti- vestigated disruption of the superior better rehabilitation of the injured tive performance of the same extreme peroneal retinaculum, which restrains ballet dancer. Therapists treating postures and movement patterns the peroneal tendons in their groove patients with ankle tendinitis should throughout their careers. Ligaments behind the ankle. He posed the ques- suspect and inquire about a history that become lax, torn, or scarred tion as to whether this injury was due of ankle sprain.13 Additionally, when following a lateral ankle sprain may to a single traumatic ankle sprain or ballet dancers experience an ankle not be able to provide the stability to “repeated episodes of overloading sprain, medical personnel should be required for these extraordinary ankle of the peroneal tendons.”66 aware that these dancers may be at activities. It has been demonstrated Geppert also noted that lateral increased risk for future tendinitis. that ligaments containing scar tissue ankle instability was associated with Therefore, special attention should be have reduced capability (lower loads several peroneal pathologies, including focused on rehabilitation of peroneal to failure and lower energy absorbing superior peroneal retinaculum laxity, strength and balance and propriocep- capacities of only 60% of normal).12 subluxing peroneal tendons, and splits tive training. Decreased bony protection in the of the peroneus brevis tendon. How- Current therapy protocols may not plantar flexed position due to the ever, he did not specify whether the adequately rehabilitate lateral ankle talus dome wedge shape, combined instability led to these pathologies or sprains and their sequelae, especially with decreased ligamentous stabil- they caused the associated instability.67 in ballet dancers. Dancers may return ity commonly associated with lateral Similarly, Clark noted that repetitive to activity too soon, before rehabilita- ankle sprains, will require increased lateral ankle sprains and instability tion is complete.5 Early return to full stabilization by surrounding muscles, can lead to laxity of the superficial activity must be weighed against the especially the peroneal group. All peroneal retinaculum, resulting in risk of long-term complications. Func- of these factors place high loads on subluxation and splitting of the pero- tional tests, such as hopping on one an already unstable ankle position, neus brevis tendon.68 Interestingly, he, foot, may indicate when the dancer is resulting in chronic overuse of these as well as others,69 recognized that the ready to return to full activity (lateral muscles, and ultimately may lead to link between these entities can also hopping appears to be a more sensitive tendinitis. occur in the opposite direction; that test than forward hopping).5 For ballet is, complete peroneal tendon rupture dancers rehabilitation should also be Sprain-Tendinitis Link can lead to recurrent ankle sprains and performed in their functional posi- Is there a link between prior ankle ankle instability. Other investigators tions, that is at significantly increased sprain and subsequent ankle tendi- have noted that peroneal tendinitis ranges of plantar flexion. nitis? A growing body of literature has been found concomitant with confirms myriad connections between delayed reconstruction of lateral ankle Suggestions for Future various pieces of this puzzle. The ligaments, but they did not make a Research literature does support the following causal connection.13 Future studies should investigate separate links: Only one investigator, Sammarco, tendinitis risk factors, the potential • Ballet dancers perform in unstable has speculated about the mechanism direct link between history of lateral ankle positions of extreme plantar of this link between ankle sprains and ankle sprain and ankle tendinitis, and flexion27; peroneal pathology.27 He noted that rehabilitation protocols for bal- • Lateral ankle sprain leads to ankle ankle instability increases the stress on let dancers following lateral ankle instability5,9,10,12,15,16; the peroneus brevis tendon, leading to sprain. Specifically, future studies to • Instability is linked to muscle tendon tears. confirm this hypothesized link could over-activity27,62; and Based on this review of the litera- include retrospective chart reviews of • Muscle overuse leads to tendon- ture, it is our belief that ankle sprains patients with tendinitis, looking for itis.27,56,61 lead to instability, for which the pero- the percentage of these dancers with a Only within the past 20 years has a neal muscles attempt to compensate. history of prior sprain, or prospective link between prior ankle sprains and Their overuse for this static stabilizing studies could be performed, following ankle tendinitis or other peroneal in- function, as well as for dynamic dance up with dancers who initially present juries been recognized. Larsen was the movements, then leads to tendinitis. with ankle sprain to determine what first to describe cases of longitudinal percentage of them go on to develop rupture of the peroneus brevis, noting Ankle Rehabilitation in tendinitis. that both of the patients in his study Dancers had a history of ankle sprain (rang- There is likely a relationship between Conclusion ing from one to ten years prior).64 A a history of lateral ankle sprain and A number of studies have investi- later review by Jones also noted that subsequent peroneal tendinitis. This gated lateral ankle sprains and their patients with split peroneus brevis knowledge may heighten awareness of residual complaints. Nearly all report tendon rents often have a history of the potential for developing tendinitis that these sprains commonly lead to lateral ankle instability.65 Sobel in- following ankle sprains and enable chronic ankle instability. The bony 30 Volume 12, Number 1, 2008 • Journal of Dance Medicine & Science

anatomy of the ankle provides reduced Orthop Trauma Surg. 1995;114:92- 25. Sammarco GJ. The foot and ankle stability in the plantar flexed position. 6. in classical ballet and modern dance. The peroneal muscles play a crucial 11. Kaminski TW, Perrin DH, Gansned- In: Jahss M (ed): Disorders of the Foot. role in stabilization of the ankle, with er BM. Eversion strength analysis Philadelphia: WB Saunders, 1982, EMG studies confirming that they of uninjured and functionally un- pp. 1626-1659. stable ankles. J Athletic Training. 26. Milan KR. Injury in ballet: a review are the first muscle group to contract 1999;34(3):239-45. of relevant topics for the physical during inversion stress. Furthermore, 12. Safran MR, Benedetti RS, Bartolozzi therapist. J Orthop Sports Phys Ther. as plantar flexion increases, bony AR, Mandelbaum BR. Lateral ankle 1994;19(2):121-9. stability declines and the muscular sprains: a comprehensive review. 27. Sammarco GJ. 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