pain in the first metatarsal sesamoid is an underdiagnosed clinical entity that may contribute up to 4% of overuse - type foot injuries , sesamoiditis maybe defined as inflammation of the sesamoid bones and/or apparatus due to varied biomechanical and nonmechanical factors causing pain in the anatomical region of the sesamoids .
the pain of sesamoiditis maybe a dull aching type or a sharp throbbing type of pain , usually of insidious onset , and may prevent the patient from walking .
it maybe over one or both the sesamoids , although the medial one is involved more frequently .
point tenderness is elicitable over the inflamed bone , usually over the inferior and medial aspect of the ball of the great toe .
however , this may not always be present as was the case in the present study . under such circumstances ,
we present here such a case and the utility of tc - methylene diphosphonate ( mdp ) single photon emission tomography - computed tomography ( spect - ct ) in making an accurate diagnosis .
a 37-year - old lady was sent for a tc - mdp bone scintigraphy for evaluation of nonspecific pain in the right foot .
three - phase bone scintigraphy was done after intravenous injection of 740 mbq ( 20 mci ) of tc - mdp .
flow [ figure 1a ] and pool images [ figures 1b and c ] of the feet were unremarkable . delayed planar imaging acquired three hours after radiotracer injection showed a faint focal area of tracer uptake in the region of the right great toe [ figure 1d ] .
spect - ct images of bilateral feet were acquired on a dedicated spect - ct system ( symbia t6 , seimens medical solutions , usa ) .
spect [ figure 2b ] and spect - ct [ figure 2c ] images showed focally increased radiotracer uptake in the lateral right sesamoid bone .
volume - rendered spect - ct image [ figure 3 ] showed the radiotracer uptake in the right lateral sesamoid bone . based on spect - ct findings
the patient underwent a change of footwear and used specifically advised shoes having insoles with sesamoid protective padding .
tc methylene diphosphonate ( mdp ) planar scintigraphy images of the patient . flow ( a ) and pool ( b ) anterior ; ( c ) posterior ) images are unremarkable . on delayed images ,
mild focal uptake noted in the region of great toe ( arrow ) [ r : right ] single photon emission tomography - computed tomography ( spect - ct ) images of feet .
ct images ( a ) do not show any abnormality of right lateral sesamoid ( arrow ) .
spect ( b ) and spect - ct ( c ) images show focal uptake of radiotracer in right lateral sesamoid ( arrow ) [ r : right ] volume - rendered tc methylene diphosphonate ( mdp ) single photon emission tomography - computed tomography ( spect - ct ) images of right foot .
the volume of focal uptake of spect ( arrow ) is superimposed on the volume - rendered ct images .
the sesamoid bones are usually two seed - shaped bones ( medial or tibial and lateral or fibular ) that lie below the first metatarsal head , embedded in the two tendons of the split flexor hallucis brevis .
their location allows them not only to modify the pressure of weight bearing but also to provide a biomechanical advantage during walking .
sesamoid disorders account for 9% of foot and ankle injuries and 1.2% of running injuries .
although anyone can suffer from a sesamoid disorder , chronic sesamoid afflictions seem to occur more frequently in active patient populations . given the myriad disorders that may affect the first metatarsophalyngeal joint ( mtpj ) ,
sesamoid disorders are often a diagnosis of exclusion and so it is important to evaluate this condition thoroughly and follow the clinical course closely .
sesamoiditis is a generalized term for a painful inflammatory condition associated with a sesamoid complex devoid of radiographic changes .
factors that increase susceptibility include a plantar flexed first ray , asymmetry in size , condylar malformation , rotational malalignment , and symmetric enlargement .
physical examination can reveal pain with direct palpation or passive distal push on the sesamoid apparatus , passive dorsiflexion of the hallux , and crepitus along the distal course of the flexer hallucis longus .
the differential diagnosis of first metatarsal sesamoid pain is varied and includes inflammatory bone disease , for example , rheumatoid arthritis or bony infection , ligamentous or tendinous disruption , avascular necrosis or osteochondritis , stress fractures , sesamoiditis , and osteoarthritis , normally occurring in a bipartite sesamoid and gout .
a sesamoid axial view allows inspection of the sesamoids , cristae , and the position of the sesamoidal apparatus .
however , they are of no help in sesamoiditis and are usually normal , as in the present case . hence , ancillary imaging maybe warranted .
a ct scan can assist the clinician in diagnosing a stress fracture or nonunion , and can delineate post - traumatic changes compared with the contralateral part .
however , its utility in the diagnosis of sesamoiditis appears limited . magnetic resonance imaging ( mri )
offers little in the direct diagnosis of sesamoid disorders , but does provide clues to the surrounding first mtpj disorders including flexor hallucis tendonitis , plantar plate disorders , osteochondral injury , or gout . although other imaging modalities are of limited use , tc - mdp bone scintigraphy maybe useful for sesamoiditis .
however , it is to be remembered that uptake of tc - mdp is seen only in 26 - 29% of asymptomatic patients .
moreover , because of its limited anatomical resolution , it is not able to accurately localize the site of radiotracer uptake to the sesamoid bone .
this is especially problematic if the radiotracer uptake is less intense , as in the present case . on planar scintigraphy , a faint focus of tracer uptake
was noted in the region of the great toe ; however , we were not able to localize its site as well as to determine its clinical significance because of faint uptake
first , it localized the uptake to the right lateral sesamoid , and second , by correcting for attenuation , it increased the uptake .
spect - ct has already been shown to be useful for foot arthritis . however , to our knowledge , no published literature exists regarding its utility in sesamoiditis .
conservative treatment for chronic sesamoiditis includes rest , ice , nonsteroidal anti - inflammatory medications , and custom - modified orthosis .
these conditions are often caused by repetitive stress , and correcting any abnormal biomechanical influences is the key to long - term success .
this correction can be done in a variety of ways including modification of activity , custom - modified orthoses , gel inserts under the sesamoids , a metatarsal bar , or an orthowedge shoe . in resistant cases , surgery maybe the only option . in the present case ,
the patient was advised specifically designed shoes having insoles with sesamoid - protective padding , and the condition improved .
sesamoiditis is an uncommon but treatable cause of metatarsalgia . in patients presenting with nonspecific symptoms ,
the present report highlights the utility of tc - mdp spcet - ct in identifying sesamoiditis as a cause of foot pain .
awareness of this fact will help in early diagnosis and proper management of such patients .
 metatarsalgia is a general term for pain in the area of the metatarsophalangeal joints . 
 sesamoiditis is an uncommon cause of metatarsalgia . 
 it is pain at the sesamoid bones beneath the head of the first metatarsal with inflammation or fracture . 
 the diagnosis is usually clinical , with localized tenderness on palpation . 
 diagnosing the cause of metatarsalgia in patients without this classical sign is difficult . 
 we present here such a case of a 37-year - old lady in whom sesamoiditis was diagnosed with technetium-99 m ( 99mtc)-methylene diphosphonate ( mdp ) single photon emission tomography - computed tomography ( spect - ct ) . 
INTRODUCTION
CASE REPORT
DISCUSSION