July 2016

Understanding turf toe: The role of foot orthoses

Orthotic-Devices-for-the-WinBy Patricia Pande, MClScPT, CSCS, CPed

Sponsored by an educational grant from medi USA.

Turf toe is a common injury in football players competing on artificial turf, but it also occurs in soccer and baseball players on natural grass and other playing surfaces. Turf toe is a sprain of the capsule of the first metatarsophalangeal (MTP) joint; increasing grades of injury may include a strain or avulsion of the plantar plate. Depending on the directional torque on the plantar flexed foot, the medial collateral ligament (MCL) of the first MTP may also be avulsed.1

Typically, turf toe is characterized by a hyperextension of the first MTP joint and involves the capsuloligamentous structures and, often, the sesamoids as well.1-3 Although turf toe also can be a hyperflexion injury, the two mechanisms warrant different modes of treatment. For clarity, turf toe in this article is defined as a hyper­extension injury with pathology to the plantar aspect of the first MTP joint, including muscle, cartilage, and bone.4

Because of its varied prevalence, turf toe is likely more a function of the flexible cleats used in soccer and football than the playing surface, and might be more appropriately named “cleat toe.” Turf toe may be misdiagnosed if the pathology is limited to ligamentous damage, lacking the muscle, cartilage, or bone pathology associated with more severe grades of turf toe.4

Bowers and Morton5 were the first to identify the turf toe injury. Shortly after the introduction of artificial turf in football, turf toe occurred at a rate of four to six injuries per season.6,7 In 1990, Rodeo et al found turf toe in 45% of professional football players.8

More recently, researchers have noted turf toe incidence in collegiate football players as .62 per 1000 athletic exposures.9 It’s 14 times more likely to occur in games than in practice, and is most common in football running backs and quarterbacks.9

Biomechanics

7Medi-iStock_26451144-copyTurf toe occurs when the foot is held in plantar flexion while the first MTP joint hyperextends. This may involve contact from another player (eg, tackling) or a braking motion from the cleat catching in the turf while the player accelerates forward or changes direction.

The first MTP joint is a condyloid joint with two degrees of freedom. During the first 20° of dorsiflexion with the foot planted on the ground, the phalanx is stabilized and the first metatarsal rolls over its base. After 20°, the peroneus longus is activated and the first metatarsal slides in the direction of plantar flexion, with concomitant dorsiflexion at the first MTP joint.10

During gait, the first MTP joint undergoes a series of rolling, sliding, and compression, with the final push-off effect enhanced by the plantar fascia and the muscular attachments.10 During sports play, the first MTP joint is pivotal to running, accelerating, and jumping. During a running jump, it undergoes forces of up to eight times body weight; these forces can make the capsuloligamentous structures more vulnerable to a turf toe injury.11

Ongoing subclinical stress to the first MTP joint has been studied in basketball players; the first ray, however, is an important consideration for football and soccer players as well.12 Its role in the windlass mechanism is most effective when the positions of the first metatarsal, sesamoid apparatus, and hallux are oriented with the plantar fascia or aponeurosis.13 Without this orientation, the sesa­moid apparatus is unable to exert a sling effect on the first metatarsal, and excessive dorsiflexion may occur.

Although turf toe is most common in running backs and quarterbacks, plantar loads (and risk of turf toe) are also very high in football linemen, as the first MTP joint is already subjected to increased tension.8 If a lineman accelerates into contact with another player, the forces are further magnified at the first MTP joint.8 This suggests that treatments to reduce stretching or excessive tension in the plantar capsule and ligament may help prevent turf toe injuries.4 Such treatments could include the use of tape, stiff-soled footwear, and orthoses designed to reduce dorsiflexion of the first MTP joint.

Foot orthoses can be used to lower the head of the first MTP joint—for example, supporting the medial longitudinal arch elevates the base of the first MTP while lowering the head.14 Performing a weightbearing Hubscher test before and after provision of an orthosis can help verify preservation of range of motion and function.14

The role of the sesamoids

The medial and lateral sesamoids are embedded in the flexor hallucis brevis (FHB) and elevate the metatarsal head to reduce plantar trauma.15 The medial sesamoid attaches to the abductor hallucis, the proximal phalanx, and the plantar fascia. The lateral sesamoid is connected to the lateral FHB and the adductor hallucis throughout the intermetatarsal ligament. Proper function of the sesamoids reduces the distraction forces on the plantar plate and may help to reduce the severity of a turf toe injury.4

First MTP joint flexion is accompanied by distal gliding and dorsal tilting of the sesamoids in the normal foot.16 The integrity of the ligaments enhances the function of the sesamoid during cutting activities (involving high varus and valgus forces), which are often associated with turf toe.3

During sports, the hallucal sesamoids are often traumatized, more commonly on the medial or tibial side, and with axial loading in a plantar flexed position.17

Causes of turf toe in sports

There is a paucity of data identifying the primary cause of turf toe, however, much of the literature cites plantar flexion with toe extension. As such, attempts have been made to prescreen athletes for tight Achilles tendons and restricted toe extension.18

Prior injury that results in hallux limitus is positively associated with turf toe injury involving the contralateral limb, while decreased range of motion at the first MTP joint has been disputed as a predictive factor.19 Hallux valgus is often associated with turf toe, and may be a complicating factor in conservative or surgical treatment.4 A survey-based study by Coker et al7 suggested an association between turf toe and pes planus, but those results have not been reproduced, and longitudinal prospective studies have not been conducted to examine the association.

Artificial turf produces a higher peak torque at the shoe-surface interface than natural grass. Whether this leads to increased injury is still a source of contentious debate.20,21 The obvious performance benefits associated with newer generations of artificial turf—including increased speed, acceleration, and torque at the shoe-surface interface—often preclude safety considerations, especially in light of the mixed research results.20,22

Studies comparing rates of injuries sustained on grass and synthetic turf are confusing, and it is difficult to extrapolate from studies of anterior cruciate ligament (ACL) and ankle injuries, for example, to injuries involving the first MTP joint. There are no randomized prospective longitudinal studies of different foot types or footwear choices that assist in our understanding of the mechanism of injury. Most recently, changes in style of play have been suggested as a cause of injury,23 and this remains an intriguing new area of research.

Soccer cleats have evolved over time to enhance performance and reduce midfoot and ankle injury. Unfortunately, the switch to more restrictive midfoot stabilization engenders overcompensation, often in the form of increased forefoot flexibility.24 Football shoes have also become lighter and more flexible, qualities that may enhance players’ performance and improve their feel of the ground.

Studies on the role of cleats in injury have focused on the ACL and ankle sprains. Research has shown the location and number of cleats are factors in reducing varus and valgus translation at the foot, which can help reduce stress on the collateral ligaments and capsuloligamentous structures.25

The role of orthoses

Clinically, foot orthoses are typically used to treat first MTP sprains; however, ultra-rigid carbon fiber is not well tolerated by athletes as it impedes form and function at push off. A prophylactic homopolymer polypropylene foot orthosis with a first ray indentation also was not embraced by most of a small sample of 24 football players;26 only one player wore the orthoses every day and just six wore them “sometimes or infrequently.” The most commonly cited reasons for noncompliance included discomfort and pain from the weight and fit, as well as the perception of performance-inhibiting characteristics associated with the devices.26

Turf toe injuries may be career-changing for many athletes. The return to sports is often slow (up to 16 weeks), depending on the severity of the injury and the position played.19 The ultra-rigid carbon fiber orthosis that is often prescribed for more severe injuries may impede the rocker action of the foot and, as mentioned, is not popular with athletes.18

Treatment must mitigate the deleterious forces on the foot with the following orthotic strategies:

  1. Reduce impact loading without the use of rigid materials that will restrict sesamoid function and increase the risk of noncompliance by the athlete.26 Using more flexible carbon fiber that allows more natural movement will be better accepted.18
  2. Allow the first metatarsal to function properly without blocking or accelerating plantar flexion and sliding of the metatarsal head.20
  3. Accommodate or dissipate forces associated with pivoting, jumping, landing, push off, and rapid changes in direction, but without inhibiting performance.20,26
  4. Allow for activity of the peroneus longus, as this is an essential stabilizer (plantar flexor) of the first ray during push off in sports.27

Turf toe in cleated sports will continue to cause concern. Our level of knowledge and biomechanics must meet this challenge. This topic is fraught with discrepancies on classification and treatment, with a lack of compliance that is not paralleled in any sport.

Patricia Pande, MClScPT, CSCS, CPed, is a physical therapist, pedorthist, and strength and conditioning specialist based in Durham, NC. She is the founder of FootCentric, an online continuing education company dedicated to comprehensive, multidisciplinary foot treatment.

REFERENCES
  1. Glasco W, Glasco G. Conservative evaluation and intervention of a sports related injury: Turf toe. J  Sports Chiropr Rehabil 1998;12(2):82-85.
  2. Brophy RH, Gamradt SC, Ellis SJ, et al. Effect of turf toe on foot contact pressures in professional American football players. Foot Ankle Int 2009;30(5):405-409.
  3. Clanton TO, Ford JJ. Turf toe injury. Clin Sports Med 1994;13(4)731-741.
  4. VanPelt MD, Saxena A, Allen MA, eds. Turf-Toe Injuries. In: Sports Medicine and Arthroscopic Surgery of the Foot and Ankle. Springer; 2012: 13-28.
  5. Bowers KD Jr, Martin RB. Turf-toe: A shoe-surface related football injury. Med Sci Sports 1976;8(2):81-83.
  6. Clanton TO, Butler JE, Eggert A. Injuries to the metatarsophalangeal joint in athletes. Foot Ankle 1986;7(3):162-176.
  7. Coker TP, Arnold JA, Weber DL. Traumatic lesions of the metatarsophalangeal joint of the great toe in athletes. J Ark Med Soc 1978;74(8):309-317.
  8. Rodeo SA, O’Brien S, Warren RF, et al. Turf toe: an analysis of metatarsophalangeal joint sprains in professional football players. Am J Sports Med 1990;18(3):280-285.
  9. George E, Harris AH, Dragoo JL, Hunt KJ. Incidence and risk factors for turf toe in intercollegiate football: data from the National Collegiate Athletic Association injury surveillance system. Foot Ankle Int 2014;35(2):108-115.
  10. Hetherington VJ, Carnett J, Patterson BA. Motion of the first metatarsophalangeal joint. J Foot Surg 1989;28(1):13-19.
  11. Nigg BM. Biomechanical aspects of running. In: Nigg BM, ed. Biomechanics of running shoes. Champaign, Il: Human Kinetics; 1986: 1-25.
  12. Tregouet P. An assessment of hallux limitus in university basketball players compared with noncompetitive individuals. J Am Podiatr Med Assoc 2014;104(5):468-472.
  13. Rush SM, Christensen JC, Johnson CH. Biomechanics of the first ray. Part II: Metatarsus primus varus as a cause of hypermobility. A three-dimensional kinematic analysis in a cadaver model. J Foot Ankle Surg 2000;39(2):68-77.
  14. Author interview with Seamus Kennedy, CPed, president of Hersco Orthotic Labs, New York City.
  15. McCormick JJ, Anderson RB. Turf toe: anatomy, diagnosis, and treatment. Sports Health 2010;2(6):487-494.
  16. Jahss MH. The sesamoids of the hallux. Clin Orthop Relat Res 1981;(157):88-97.
  17. Nwawka OK, Hayashi D, Diaz LE, et al. Sesamoids and accessory ossicles of the foot; anatomical variability and related pathology. Insights Imaging 2013;4(5):581-593.
  18. Chinn L, Hertel J. Rehabilitation of ankle and foot injuries in athletes. Clin Sports Med 2010;29(1):157-167.
  19. Eggert KE. First metatarsal joint range of motion as a factor in turf toe injuries. Master’s thesis. University of Houston, TX; 1991.
  20. Villwock MR, Meyer EG, Powell JW, et al. Football playing surface and shoe design affect rotational traction. Am J Sports Med 2009;37(3):518-525.
  21. Orchard JW, Powell JW. Risk of knee and ankle sprains under various weather conditions in American football. Med Sci Sports Exerc 2003;35(7):1118-1123.
  22. Meyers MC, Barnhill BS. Incidence, causes, and severity of high school football injuries on FieldTurf versus natural grass: a 5-year prospective study. Am J Sports Med 2004;32(7):1626-1638.
  23. Williams JH, Akogyrem E, Williams JR. A meta-analysis of soccer injuries on artificial turf and natural grass. J Sports Med 2013;2013:380523.
  24. Hilgers MP, Walther M. Evolution of soccer shoe design. Athletic Therapy Today 2011;16(3):1-4.
  25. Hennig EM. The influence of soccer shoe design on player performance and injuries. Res Sports Med 2011;19(3):186-201.
  26. Fair J, Keblish D, Rabaiotti A. Foot orthoses and injury prevention in football. LER 2013;5(3):55-59 .
  27. Dullaert K, Hagen J, Kloski K, et al. The influence of the peroneus longus muscle on the foot under axial loading. A CT evaluated dynamic cadaveric study. Clin Biomech 2016;34:7-11.
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3 Responses to Understanding turf toe: The role of foot orthoses

  1. Harvey Johnson C.O. says:

    There are multiple issues with ultra rigid prefab carbon graphite shanks causing fitting problems resulting in the athlete not tolerating the shank.
    1. Sizing is nearly impossible to accommodate the difference in rockers in various shoes from sport to sport shoes as well as the width and length of the shoes. Large football and basketball players require sizes greater than offered in the market place. Often times the rocker on prefab shanks actually “bridges” the area directly under the metatarsal head which increases pressure on the 1st MTP. This not only increases pressure on the sesamoids but also reduces room for a full length custom orthotic. Because these prefab carbon shanks are laminated the rocker cannot be heated and modified to fit the shoe with perfect fit along the length of the rocker.
    I use a product with nylon resin, fiberglass weave overlaid with unidirectional carbon fiber. Heating it to 450 degrees I have templates for different rockers. I also have 3 levels of strength to accommodate the desired level reduction of dorsiflexion to 1st MTP . Depending on the size of the athlete and how acute the injury is determines the material I use. Because I carry the material in 36″ square sheets I can make shanks up to size 22 feet. I have much better compliance with a true custom molder shank than with prefab graphite shanks that commonly bridge the forefoot. Also the prefabs slide around in the shoe to do poor fitting. Size 14 prefab shanks do not have any control over the 1st MTP of a size 15 and above foot. Yet I often see athletes in my clinic with a short shank and long foot. Just dorsiflex the forefoot with my and the shoe bends. Why even bother putting in a short shank? All it does is take up space and lacks any lever arm to reduce motion on the MTPs.
    Full length orthotic insoles I design requires one of 2 modifications depending on whether the sesamoids and plantar plate are involved or just a simpler sprain is the pathology.
    1. Simpler sprains I use a modified full length medial wedge forefoot orthotic where I “drop out” the area under the distal aspect of the great toe from the I.P. joint to the very anterior aspect of the toe. This tapered drop out increases the area for the great toe to have more room for the toe to sit in plantar flexion before the heel rises. As the heel rises there is a delay in the “dorsiflexion lever arm”. I find that adding just a few degrees (2-3) more available room often reduces (judged by pain reported by the athlete) stress to the 1st MTP. Often this modification alone is enough to significantly reduce chronic turf toe symptoms without the use of a shank.
    2. With severe sprains that may or may not include plantar plate disruption and sesamoid involvement I use the same custom shank but modify the orthotic insole differently from the above mentioned mild sprain.
    Again I build a full length medial wedge insert but then I drop out completely the area under the 1st met head and extend it to the very distal aspect of the great toe. I may add a small layer of poron under the area to reduce shock to the sesamoids. Often with football and soccer shoes I have to re-lace the shoe to allow for the extra thickness of both the custom shank and custom full length orthotic. Basketball shoes have much more available room and only sometimes require re-lacing.
    Fine tuning both the custom molded shank and carefully modifications to the foot orthotics have dramatically improved my clinical outcomes with elite athletes.
    Additionally I find that the “drop out” techniques are very useful with hallicus rigidus in the middle aged population as well as H.R. and or sesamoiditis in runners.

  2. Harvey Johnson C.O. says:

    I left out one additional but very important modification for improved function to a good custom molded shank.
    I always grind the area under the heel and just anterior to the heel of the shank to increase flexibility.
    A rigid or even semi rigid shank while pump the heel out of the shoe when the heel rises. As the forefoot of the shank restricts motion at the MTPs the lever arm forces the heel to rise inside the shoe. This is not only uncomfortable to the athlete as the pumping action aggravates the posterior heel but when the heel rises in the shoe it allows the MTPs to flex. This essential reduces the ability of the shank to control dorsiflexion at the MTPs. I learned quickly when I listened to my patients complain of “my heel is coming out he shoe” and then also found that grinding the area under and just anterior to the heel improved function. No wonder that studies have shown athletes do not like shanks.

  3. Harvey Johnson C.O. says:

    I left out one additional but very important modification for improved function to a good custom molded shank.
    I always grind the area under the heel and just anterior to the heel of the shank to increase flexibility.
    A rigid or even semi rigid shank will pump the heel out of the shoe when the heel rises. As the forefoot of the shank restricts motion at the MTPs the lever arm forces the heel to rise inside the shoe. This is not only uncomfortable to the athlete as the pumping action aggravates the posterior heel but when the heel rises in the shoe it allows the MTPs to flex. This essential reduces the ability of the shank to control dorsiflexion at the MTPs. I learned quickly when I listened to my patients complain of “my heel is coming out he shoe” and then also found that grinding the area under and just anterior to the heel improved function. No wonder that studies have shown athletes do not like shanks.

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