In this series of articles we’ll be discussing sesamoid injuries, hallux limitus and hallux rigidus, turf toe, and other, similar first metatarsophalangeal (MTP) joint injuries. We’ll be starting with a quick overview of mild to moderate turf toe.
A properly functioning first metatarsophalangeal joint is critical for running.
In evolution, the abduction of the first ray, disappearance of an opposable hallux, and realignment of the first metatarsophalangeal joint and first metatarsocuneiform joint marked a complete change from arboreal living to obligate bipedalism. Ardipithecus ramidus, the oldest known hominid, had an adducted first metatarsal, opposable hallux, and was able to walk in a bipedal manner (Lovejoy, Latimer et al. 2009). When Australopithecus evolved with a more modern alignment of the great toe, hominids became obligate bipeds and as they evolved to Homo habilis and Homo erectus gained the ability to run.
The first metatarsophalangeal joint includes 4 bones. The most readily apparent portion of the joint is the articulation between the concave shaped base of the proximal phalanx and the convex, rounded head of the first metatarsal. The plantar surface includes the two sesamoid bones (fibular or lateral and tibial or medial) and the joint capsule. The joint capsule is reinforced on its plantar aspect by both a fibrocartilagenous plate and the plantar accessory ligament. The flexor hallucis longus and flexor hallucis brevis attach on the plantar aspect, along with the abductor hallucis muscle and the adductor hallucis muscle.
Dorsally the tendons of the extensor hallucis longus and the extensor hallucis brevis muscles insert.
Turf toe, sesamoiditis, and hallux rigidus are a functionally interconnected set of injuries. These problems can impair the ability to run. In severe cases a runner may consider giving up their sport permanently. We’ll examine these entities individually and review treatment.
The hallucal sesamoid bones are associated as a portion of the first metatarsophalangeal joint complex, along with the big toe and the first metatarsophalangeal joint. The sesamoid bones are embedded within the tendon of the flexor hallucis brevis and are linked together by the intersesamoidal ligament. They function as a fulcrum, although some describe the function as being more like a pulley. The primary effect of the sesamoids is to increase the mechanical advantage of the flexor hallucis brevis, which plantar flexes the big toe.
Sesamoid pathology is more complex than the term “sesamoiditis” would imply. Methodical analysis will allow one to distinguish among the myriad entities that may occur in this location. Richard Bouché, D.P.M. has lectured often on the “sick sesamoid” and has coined the term sesamoidopathy. That is an excellent term one may apply to sesamoid injuries in which the diagnosis has not been further refined.
Many problems that can affect the sesamoid bones including traumatic fracture, stress fracture, avascular necrosis, chondromalacia of the sesamoid bones, osteoarthritis, and a variety of inflammatory entities.
The sesamoid bones are found up to 10% of the time to be in multiple pieces termed multipartite and most often it would be two pieces or bipartite. Only 25% of the time does this occur on both sides. A comparison x-ray can sometimes be helpful in determining if a fracture is present. If the bipartite appearance is present bilaterally, there is a greater chance that the sesamoid is truly bipartite and not fractured. Clues of fracture include irregular and jagged appearance of the separated surface, irregular and uneven “pulling” apart of the sesamoidal fragments.
X-ray examination should include A-P (D-P – dorsoplantar), lateral, oblique and axial views. Magnetic resonance imaging (MRI) examination can also be useful.
Traumatic fractures can be viewed on either exam. Stress fracture can be determined best with MRI, with a bone scan also an aid.
Differential Diagnosis of Sesamoidopathy
Tapered sesamoid accomodation
Causes of Pain in Sesamoid Region
Treatment of Sesamoidopathy
Treatment of sesamoidopathy may include padding, orthotics, or surgery. Immobilization is used in severe cases. Non-weightbearing is usually not necessary, but may be used if necessary. Gentle hallux range of motion exercises should be begun once improvement is seen, usually within 1 to 2 weeks. A pneumatic walking boot may be found to be more comfortable than a cam walker.
In the long term, orthotics with a sesamoid accommodation are often helpful. Surgical procedures that have been used include relocation, complete or partial excision of the tibial or fibular sesamoid, sesamoidal planing, and metatarsophalangeal joint fusion.
Treatment Summary for Sesamoid Injuries:
Careful assessment followed by the appropriate treatment:
- Off loading orthotic with sesamoid accomodation.
- Gentle Range of Motion exercises or Physical Therapy as needed.
- Rocker sole or stiff forefoot on footwear.
Functional Orthoses Modifications For Sesamoidal Pain
Inverted cast correction
Medial heel skive
Deep heel cup
Minimal arch fill on cast
Reverse Morton’s Padding
Kinetic Wedge (R)
Other techniques to off load the first ray.
Sesamoid Pain - Treatment Summary:
Careful assessment followed by the appropriate treatment:
PRICE: Protection, Rest, Ice, Elevation.
Offloading Orthotic with Sesamoid Accommodation
|“...offloading... directly removes pressure from the sesamoidal apparatus, places the great toe in a good functional position, and eliminates the early, rapid change in position of the great toe that takes place as the gait cycle passes through heel off...”
For information on related topics read the articles available here on hallux rigidus and turf toe. We have reviewed these troubling injuries. Careful assessment and review of differential diagnoses should lead to the proper diagnosis. Successful diagnosis and treatment of your patients is the first step towards overall success.
Clanton TO, Ford JJ., Turf toe injury. Clinics in Sports Med 13(4):731-735, Oct. 1994
Coker, T. P, Arnold, J. A., & Weber, D. L. (1978). Traumatic lesions of the metatarsophalangeal joint of the great toe in athletes. The American Journal of Sports Medicine, 6(6), 326-334.
Lovejoy, C. O., B. Latimer, et al. (2009). "Combining prehension and propulsion: the foot of Ardipithecus ramidus." Science 326(5949): 72e71-78.