Cuboid subluxation in ballet dancers PETER MARSHALL,* MA, PT, AND WILLIAM G. HAMILTON, MD

From the American Ballet Theater, New York, New York

ABSTRACT cuboid will usually yield excellent and often dramatic results in the management of this commonly overlooked affliction. Cuboid subluxation is a common but poorly recognized A dancer (or athlete) with a cuboid subluxation will com- condition. Its include lateral midfoot and symptoms pain plain of lateral pain and weakness in push-off. The pain an to "work the foot." In addition, inability through often radiates to the plantar aspect of the medial foot, the on the surface of the cuboid in a dorsal pressing plantar anterior or the fourth The direction produces pain. The normal dorsal/plantar joint, distally along ray. dancer usually feels an inability to &dquo;work the foot,&dquo; is reduced or absent when to the unin- through play compared while from foot-flat to or full jured side, and subtle forefoot valgus is present. Fre- moving demi-pointe pointe. Dancing vigorously and jumping are usually impossible be- there is a shallow depression on the dorsal quently, cause of dorsalward on the surface of the foot and fullness on the localized, sharp pain. Pressing palpable plantar surface of the cuboid is The cuboid’s mini- aspect of the cuboid. Documentation by radiograph, plantar painful. mal joint play is markedly reduced or absent CT scan, or magnetic resonance imaging is difficult dorsal/plantar because of the normal variations found in the relation- when compared to the uninvolved foot. ship between the cuboid and its surrounding structures. Severely subluxated cuboids sometimes leave a shallow, The diagnosis is primarily subjective, and must be made visible depression on the dorsum of the cuboid and a fullness on the to on the basis of the patient’s history and physical find- plantar aspect. Unfortunately, repeated attempts ings. Treatment requires recognition of the condition, document or confirm the diagnosis by radiographs, comput- erized axial or resonance manual reduction by a therapist or physician familiar tomography (CT) scans, magnetic with the condition, and followup to be certain that the imaging (MRI) studies have been unsuccessful because of cuboid remains in place. Therapists and orthopaedists normal variations between the cuboid and its surrounding involved in the care of dancers should be alert to the structures. Other authors agree that this is probably caused possibility of cuboid subluxation and be able to recog- by the minimal amount of subluxation that is present nize it when it occurs. Indeed, the term &dquo;locked cuboid,&dquo; used by Hiss5 s may more accurately describe this condition. This term suggests a small subluxation that markedly reduces the normal motion in the midtarsal (Chopart’s) joint, altering the normal me- chanics and the between the hindfoot and fore- In spite of the scarcity of information in the medical litera- relationship foot. Other well-known and conditions such ture on cuboid subluxation,’ experience with professional well-accepted as subluxations of the ’ and ballet dancers suggests that this is a common but poorly metatarsophalangeal of the foot&dquo; cannot be documented on recognized affliction.’ We report the incidence of cuboid radiographs and the must be made on the basis of the subluxation in American Ballet Theater, one of America’s diagnosis patient’s premier international ballet companies. The characteristic history and physical examination. symptoms, physical findings, and theories regarding its Occasionally, the fourth metatarsal may subluxate on the cuboid. These subluxations can be mistaken for cause are presented, as well as a variety of manual therapeu- easily plan- tic techniques that reduce the subluxated cuboid and sub- tar subluxations of the cuboid, because the base of the fourth luxation of the fourth metatarsal on the cuboid. When the metatarsal almost always moves dorsally in the dancers we physician is alert to this syndrome, it can be easily recog- have seen. This diagnosis is aided by the fact that a sublux- nized. Patience and practice in manual reduction of the ated metatarsal acts like a log floating in the water-when one end rises, the other end sinks. Thus, when the base of the fourth metatarsal subluxates dorsally on the cuboid, the * Address correspondence and repnnt requests to Peter Marshall, MA, PT, head of the metatarsal will be Physical Therapist, Baryshnikov Productions and The White Oak Dance Project, plantarflexed (&dquo;dropped&dquo;) 111 East 14th Street, Suite 385, New York, NY 10003. when compared to the adjacent metatarsals and the fourth 169 170

metatarsal of the uninvolved foot (Fig. 1). Dancers with dorsal subluxations of the base of the fourth metatarsal present with the same symptoms as dancers with plantar subluxation of the cuboid. They are also predisposed to capsular irritation (&dquo;stone bruises&dquo;) of the plantar aspect of the head of the prominent fourth metatarsal. Most professional female ballet dancers have dorsal cal- losities (&dquo;toe shoe knots&dquo;) over the dorsum of the metatarsal heads. Thus, the absence of a callus over the fourth meta- tarsal head indicates that the fourth metatarsal has been in plantarflexion for some time and may be a normal condition for that particular dancer, especially if she has the same configuration in the other foot. This finding alone does not necessarily rule out an acute dorsal subluxation of the base of the fourth metatarsal, but it greatly diminishes its prob- ability. 2. To an abducted midtarsal the Abduction of the forefoot at the midtarsal joints predis- Figure realign joint, patient’s foot is between the clinician’s , the medial poses an individual to plantar cuboid subluxation.&dquo; Careful positioned foot is contacted at the distal talus and the lateral foot at the inspection of the relative position of the forefoot to the lateral of the and an adduction force is then hindfoot will often reveal a subtle midfoot abduction when aspect cuboid, the clinician’s hand the cuboid subluxates, in comparison to the uninvolved foot. applied by and knees. The abducted position of the foot must be corrected or TABLE 1 diminished to facilitate and maintain reduction of the cuboid Incidence of cuboid injuries in professional dancers (Fig. 2). The tendency for ballet dancers to seek the valgus position of the forefoot when on releve may predispose them to cuboid subluxation. Cuboid subluxation secondary to a of the lateral foot or ankle is more difficult to detect because it is easy for the clinician to assume that the dancer’s complaints are because of injured soft tissues. Effusion and ecchymosis make determination of the cuboid’s joint play, or visible detection of a shallow depression, difficult. While pressing dorsalward on the plantar aspect of the cuboid may be uncomfortable to anyone with a sprain of the lateral foot, it causes severe pain in someone who has sustained a cuboid subluxation accompanying such a sprain. Lingering symp- toms and disability may indicate that cuboid subluxation has occurred along with the injury.

Incidence

The records of all injuries requiring treat- ments in the American Ballet Theater were reviewed during two separate 3-week periods to examine the incidence of cuboid subluxations during both performance and rehearsal schedules. The records examined were from a 3-week per- formance season in Los Angeles during March 1986 and from a 3-week rehearsal schedule in New York City during January 1987. Cuboid subluxations totaled over 17% of foot and ankle injuries during these two periods (Table 1). There were no significant differences between the performance and the rehearsal schedules. Newell and Woodie’ reviewed the records of 3600 athletes with foot injuries and found that 4% of their symptoms came from the region of the cuboid bone. The incidence of cuboid- related difficulties appears to be higher in professional dan- cers than in other athletes. This disparity is presumably due Figure 1. The &dquo;dropped&dquo; fourth metatarsal head. to the technical and aesthetic demands of ballet. 171

Etiology Treatment

While Newell and Woodie8 found that 80% of cuboid sub- Management of a cuboid subluxation involves proper diag- luxations in athletes occurred in pronated feet, we have not nosis, reduction of the subluxation, and maintenance of the found this to be true in dancers. We found that cuboid reduction. The &dquo;cuboid whip&dquo; has been the standard tech- subluxation occurred in all foot types, including cavus feet nique for reducing the cuboid. It was described by Newell (the most desirable in ballet). A cavus forefoot can still and Woodie (although not named as such) in 1981.~ pronate in relation to the hindfoot, and the dancers who Marshall’ described an adaptation of the technique, and pronate (usually to compensate for deficiencies in turnout called it the &dquo;cuboid squeeze.&dquo; He now describes the cuboid from the and ) appear to have an increased incidence whip and squeeze as well as two previously unreported, of cuboid subluxation. effective techniques. Before attempting any of these tech- Newell and Woodie also hypothesized that pronation al- niques, the clinician must relax the long dorsal extensors lowed the to pull the lateral portion of the and peronei with deep massage. cuboid dorsally, causing the medial border to subluxate The cuboid squeeze and cuboid whip are performed with plantarward. In our experience, a cuboid has rarely been the patient in the prone position. The clinician stands at found in this position on physical examination. However, the patient’s feet and holds the forefoot with his fingers the peroneus longus may play a role in some cases. It while his thumbs are placed on the plantar surface of the becomes tight after a cuboid subluxation and should be cuboid. In the cuboid whip, the forefoot is then whipped into relaxed with deep massage of the muscle belly before at- plantarflexion as the physician’s thumbs simultaneously tempting reduction, which is difficult during peroneal spasm. deliver a dorsally directed reduction force on the bottom of Cuboid subluxation occurs more frequently in female dan- the cuboid. An alternate position has the patient prone and cers and is often of a different type than in male dancers. lying at table’s edge with the hip and knee flexed over the Generally, cuboid problems occur acutely in male dancers side of the table. as they land (presumably pronating their foot and ankle) In the cuboid squeeze, the clinician gradually stretches from one jump, or a series of big jumps, in a bravura the foot and ankle into maximal plantarflexion. When the variation. Female dancers, on the other hand, experience examiner feels the dorsal soft tissues relax, the cuboid is cuboid difficulties more often as part of an overuse syn- reduced with a final squeeze with the thumbs (Fig. 3). Our drome. Anyone who has seen a ballerina bourr6 across the experience suggests that the cuboid squeeze is far more stage (move across the stage on full pointe) or perform 32 effective than the cuboid whip. The cuboid squeeze affords fouettes (rapid spinning movements combined with releves the therapist better control of the direction and intensity of from foot-flat to full pointe) can appreciate the contributing the reduction force and, unlike the cuboid whip, none of the factors to cuboid subluxation faced by the ballerina as she reduction force is absorbed by the dorsal soft tissues. performs pointe work. Indeed, cuboid subluxation in female An alternative technique effectively reduces cuboid sub- ballet dancers, and occasionally in male dancers, may be luxations and, with minor changes in hand placement and secondary to dorsal ligamentous laxity associated with hy- direction of the reduction force, is the treatment of choice permobility of the joints of the midfoot that is so frequently for dorsal subluxations of the base of the fourth metatarsal. seen in dancers. This hypermobility may simply be the price This technique can be performed with the patient supine paid by a dancer who has aesthetically pleasing, beautifully pointed feet (plantarflexion in slight valgus), or it may develop over time. We believe that a dancer moving from foot-flat to demi- pointe or full pointe initially places a dorsiflexion moment on the tarsometatarsal joints and joints of the midfoot. If the dancer goes past full pointe, as dancers with flexible feet often do, the forces are reversed and a plantarflexion mo- ment is then in effect as she goes &dquo;over the top&dquo; and begins to dance on the dorsum of the toes and metatarsals. A dorsiflexion force returns as the dancer descends to full-foot contact with the floor. These repetitive force alterations may gradually decrease the stability of the midfoot, predis- posing some dancers to cuboid-related difficulties. Cuboid subluxation can also be the sequelae of a traumatic sprain of the lateral foot. This is particularly true of a sprain involving the dorsal calcaneocuboid and the dorsal cuboid-third, or cuboid-fourth, metatarsal ligament. Cuboid subluxations that occur secondary to such acute must be managed carefully if one is to prevent a chronic Figure 3. The correct position, hand placement, and direction condition from developing. of the reduction force for performing the cuboid squeeze. 172 and the examiner standing at the patient’s feet, and requires the clinician to &dquo;hang&dquo; the patient’s lower extremity by grasping the fourth metatarsal, thus allowing gravity and the weight of the leg to help distract the cuboid-fourth metatarsal joint. This distraction is critical to the success of the technique and requires the complete relaxation of the patient’s involved lower extremity. In cases where the cuboid is subluxated, the fourth metatarsal is then pulled in a longitudinal direction with the forefoot in slight plantarflex- ion (Fig. 4). Successful reductions are usually audible when performed in this manner. Dorsal subluxations of the base of the fourth metatarsal are reduced similarly. The clinician uses the same hand placement as pictured in Figure 4. The fourth metatarsal- cuboid articulation is distracted by gravity as described previously. The final reduction force is produced with the second and third fingers by exerting a force in the plantar direction to the dorsal base of the fourth metatarsal, while simultaneously directing a dorsiflexion force with the thumbs to the plantar aspect of the head of the fourth metatarsal. Although the techniques we have described will result in successful reductions at least 90% of the time, additional Figure 5. The clinician reduces the cuboid using the lateral of his or her second methods are needed in recalcitrant cases. One such method aspect metacarpal. The forefoot is has the patient supine and the therapist standing at the foot maximally pronated on a neutrally positioned rearfoot before a reduction force. of the table. The forefoot is maximally everted on a neutrally delivering positioned rearfoot and maintained by the therapist’s hand. The reduction force is delivered by the lateral aspect of the periods of time will experience a residual discomfort for second metacarpal (Fig. 5). Frequently, the cuboid will re- several days after the reduction. This depends on the sever- duce before the final pressure is delivered. ity and duration of the subluxation, although the feeling of Successful reduction is usually, but not always, audible weakness should disappear immediately. Individuals who and, in cases treated within 24 hours of onset, it produces have chronic subluxations fall into two categories: those who immediate and complete resolution of pain and dysfunction. frequently and easily subluxate and likewise reduce with Individuals who have had a cuboid subluxated for long ease, and those who subluxate with less frequency, but whose reductions can be taxing. The &dquo;easy&dquo; group will usually have complete resolution of symptoms after reduction, while the more difficult group may complain of an ache for a day or two. It is important to realize that despite the type of subluxation present and reduction method employed, there is never any doubt in the mind of the patient if a complete reduction has occurred. A partial cessation of symptoms signals a partial reduction, and complete reduction should be attempted. Occasionally, attempts to reduce a subluxated cuboid will be unsuccessful. Repeated unsuccessful attempts are painful to the patient and should be avoided. In these cases, we recommend that the patient be treated with massage and ice and the reduction be attempted the following day. Whenever possible, the dancer should refrain from vigor- ous activity for a day or two after reduction to avoid a recurrent subluxation. However, when a day of rest is not possible, a 1/a-inch felt pad is placed beneath the cuboid on the plantar aspect of the foot, and secured using the taping method shown in Figure 6. This is recommended to maintain I the reduction. To repeat this method, a 11/2- to 2-inch elastic Figure 4. The examiner &dquo;hangs&dquo; the patient’s injured foot by adhesive tape should be used and placed directly on the skin grasping the fourth metatarsal. Cuboids are reduced with a for maximum stabilization. The dancer is supine on a table distraction force in the direction of the arrow. with his/her foot off the table edge. Begin by applying tape 173

the cuboid squeeze is not recommended because the direction of the reduction force may cause further damage to trau- matized tissues. Successful reduction should be maintained with felt and tape as described previously. A cuboid that subluxates recurrently may indicate that the joint capsule and have not healed adequately to maintain the reduction, and repeated reductions should be avoided. A minimum of 2 to 3 days before attempting another reduction is recommended. The management of chronic subluxations should include instruction in self-mobilization techniques; otherwise, a de- pendency can develop between the dancer and the physical therapist. The most successful self-mobilization techniques are shown in Figure 7. These techniques are particularly successful in individuals who reduce easily when the cuboid squeeze is performed. Dancer and therapist should only reduce chronically subluxating cuboids when absolutely nec- essary, as further laxity may develop that only exacerbates the problem. Acute lateral midfoot pain can be produced by conditions other than subluxation of the cuboid. Therefore, in cases where a cuboid subluxation is suspected but treatment is unsuccessful, other diagnoses should be considered: ~ Unrecognized fracture or stress fracture. ~ Acute tendinitis of the peroneus longus or the os pero- neum. ~ The sinus tarsi syndrome. 1, 10 ~ Lateral process fracture of the talus.’ ~ Fracture or of the anterior of the os calcis.3 6. A minimal, method is used to process Figure three-piece taping ~ of the lateral talocrural and subtalar maintain reduction of the cuboid subluxation. Derangement joints. Begin taping ~ The meniscoid of the ankle.13 from the medial aspect of the foot (A), and continue from the Further diagnostic studies should be as indicated. lateral The final secures the foot. performed aspect (B). step (C) (See If severe is and the cannot bear text for with from Marshall P: pain present patient weight, details.) Reprinted permission obviously the foot should be examined for acute fracture The rehabiliation of overuse foot in athletes and injuries before manipulation is performed. dancers. Clin Sports Med 7: 175-191, 1988. ILLUSTRATIVE CASES to the medial aspect of the foot, starting proximal to the first metatarsal head (Fig. 6A). Place the tape around the Case1 heel and then continue to the plantar aspect of the medial longitudinal arch. Continue by encircling the rearfoot and A 38-year-old male principal dancer made a choreographed midfoot twice. Figure 6B is similar, except that the tape is exit from the stage during the first act of Giselle. As soon as initiated from the lateral aspect of the foot. (For the sake of the wings were cleared, he exhibited an antalgic gait and clarity, the previously applied tape is not shown.) Taping is reported the sudden onset of left lateral foot pain after secured with a final circumferential strip of tape (Fig. 6C), landing from a jump while slightly off balance. He com- which should preferably be 3 inches in width. This taping plained of left foot &dquo;weakness&dquo; and feared that he could not also can be incorporated into a &dquo;J&dquo; strapping for greater continue to perform. He was scheduled to return on stage in control of the subtalar joint. Asking the dancer to releve five less than 5 minutes. A brief examination revealed a marked or six times following a successful reduction will help deter- loss of plantar/dorsal excursion of the cuboid and palpation mine whether the reduction will be maintained. of the plantar aspect of the cuboid was sharply painful. He Cuboid subluxation following a second-degree or third- was positioned supine and the manipulation shown in Figure degree lateral foot sprain calls for special care to prevent a 4 was performed. An audible reduction occurred and the chronic condition from developing. If a cuboid subluxation dancer reported immediate cessation of pain and dysfunc- is suspected after a lateral foot sprain, the therapist should tion with normal weightbearing and releve. He returned to refrain from attempting a reduction until the effusion and the stage as scheduled and performed without pain or dis- ecchymosis have significantly diminished and the possibility comfort. A felt pad and tape were applied at intermission to of fracture has been ruled out. This usually occurs in 3 to 7 maintain the reduction. Five years after the incident, the days. A gentle reduction can then be attempted; however, dancer has not experienced another subluxation. 174

The cuboid was reduced, but subluxated again three times: 5, 8, and 20 days after the original reduction. Each time the cuboid was reduced successfully using the same technique, and taping was used to stabilize the midfoot and hindfoot. Five years after initial injury, the dancer has not experienced any cuboid difficulties.

Case 3 A 23-year-old female soloist presented with complaints of lateral left foot pain that prevented her from rehearsing or performing regularly. There was no trauma associated with the gradual onset of this pain, which persisted for 2 years in spite of treatment with physical therapy, nonsteroidal an- tiinflammatory medications, and multiple cortisone injec- tions. An extensive workup had been negative. Physical examination revealed a complete loss of normal dorsoplantar glide in the left cuboid bone. Slight abduction of the left midfoot and forefoot was present when compared to the opposite foot. Trophic changes were seen over the dorsum of the area secondary to the multiple cortisone injections. The patient was treated daily with midtarsal joint adduc- tion mobilizations (Fig. 2), along with rigorous attempts to return dorsoplantar motion to the cuboid. This motion was reestablished after 1 week and she was able to dance with less pain. The dancer was treated again 3 months later. During this period, marked improvement in cuboid mobility was achieved and several successful manipulations were performed (Fig. 5). The patient was instructed in self-mo- bilization (Fig. 7). Since that time, she has shown continued improvement, rarely experiences any significant cuboid-re- lated discomfort, and has received several promotions in her ballet company.

CONCLUSIONS

Cuboid-related subluxations occur with consistent, signifi- cant frequency in high-level professional ballet dancers. Figure 7. Self-mobilization techniques for cuboid subluxation. With experience, the clinician can recognize and treat this The dancer a reduction force via the cuboid provides squeeze syndrome. Management centers around the appropriate re- (A) or by the base of a ballet barre (B). duction and maintenance of the cuboid or fourth metatarsal. Technique factors predisposing an individual to subluxa- Case 2 tions should also be addressed to avoid recurrence. Lastly, clinicians should that the techniques discussed in A 27-year-old female soloist sprained her lateral left foot recognize this article can be to reduce subluxations of other while in the demi-pointe position. Marked pain and effusion adapted tarsometatarsal articulations. Although much of our study followed and the dancer was sent for orthopaedic evaluation. is based on anecdotal evidence, the suggest a dis- Radiographs taken at that time were normal and the dancer findings received daily physical therapy. Four days later, sharp pain tinct clinical entity. Other conditions, such as subluxations of the and tarsometatarsal are persisted about the lateral foot and a bone scan was per- glenohumeral joint joints, that must based on the and formed to rule out bone abnormality. The scan was normal. diagnoses be history physical Two days later, enough effusion and ecchymosis had re- examination alone. As the cuboid subluxation becomes bet- solved to allow further examination. At this time, a cuboid ter recognized and therapists are more aware of the problem, subluxation was suspected, and a gentle reduction of the perhaps reliable methods of documentation or confirmation cuboid was performed using the method shown in Figure 5. can be found. 175

ACKNOWLEDGMENT 5. Hiss JM: Establishing a foot practice. J Am Osteopath Assoc 27. 536-541, 1928 6. Hiss JM Functional Foot Disorders Los Angeles, The Oxford Press, 1949, The authors thank Gary Giffune, a member of Ballet Ari- pp 295-322 zona, for the illustrations in this manuscript. 7. Jobe F: Diagnoses and nonoperatme treatment of shoulder injuries in athletes Clin Sports Med 8. 419-438, 1989 8. Newell SG, Woodie A: Cuboid syndrome. Physician Sportsmed 9(4) 71- REFERENCES 76, 1981 9. Marshall P. The rehabilitation of overuse foot injuries in athletes and 1 Bernstein RH, Bartolomei FJ, McCarthy DJ: The sinus tarsi syndrome: dancers Clin Sports Med 7(1): 175-191, 1988 Anatomical, clinical, and surgical considerations. J Am Podiatr Med Assoc 10. Taillard W, Meyer JM, Garcia J, et al: The sinus tarsi syndrome int Orthop 75: 475-480, 1985 5: 117-130, 1981 2 Blakeslee TJ, Morris JL Cuboid syndrome and the significance of midtarsal 11. Taplin GC: Foot technique. J Am Osteopath Assoc 27: 606-608, 1928 joint stability. J Am Podiatr Med Assoc 77: 638-640, 1987 12. Thompson FM, Hamilton WG: Problems of the second metatarsophalan- 3 Harburn T, Ross H: Avulsion fracture of the anterior calcaneal process. geal joint Orthopedics 10. 83-89, 1987 Physician Sportsmed 15(4) 73-80, 1987 13. Wolin I, Glassman F, Sideman S, et al: Internal derangement of the 4 Hawkins LG Fracture of the lateral process of the talus. J Bone Joint Surg talofibular component of the ankle Surg Gynecol Obstet 91: 193-200, 47A: 1170-1175, 1965 1950