A neurotrophic joint (also known as a Charcot joint) referstoa progressive egenerative / destructive joint disorderinpatients with abnormal painsensation and proprioception[1].

Any condition causing loss of peripheral sensation, proprioception and fine motor control result in neuropathic alteration of the joints. The Etiological causes vary from metabolic disorders like the diabetes mellitus to spinal cord lesions such as syringomyelia, spina bifida, tabes dorsalis etc. The most common cause behind neurotrophic joint is diabetes and the foot is the most is the most affected region. Prevalence differs depending on severity of the disease [2] – 0.1 % in general diabetic population, 15% in high risk diabetic population and 30% in patients with peripheral neuropathy.

Two primary theories have been advanced in the development of neurotrophic joints.

Neurotrauma: The neuropathic patient is blind to the repeated microtrauma to the affected joint caused by loss of proprioception and peripheral sensation. The inflammatory resorption of the damaged bone leaves the affected area weak and vulnerable to more trauma. Furthermore, insufficient fine motor control causes abnormal pressure on some joints, which increases the risk of microtrauma.

Neurovascular : Autonomic nervous system reflexes are dysregulated in neuropathic individuals, and de-sensitized joints have markedly increased blood flow. When combined with mechanical stress, the ensuing hyperemia causes an increase in osteoclastic resorption of bone, which ultimately results in the disintegration of bone.

Inreality, both of these mechanism sprobably play a role in the development of a Charcot joint[3].

Patients frequently exhibit painless instability of the afflicted joint at presentation, and frequently they do not have any medical history that would suggest a spinal lesion as the primary cause of the neurotrophic joint. Therefore, MRI spine examinations must to be performed in each instance of neurotrophic joint and ought to be a standard component of patient care [4].

Aim and objectives

To study the incidence of Spine

• Lesions as a primary causative factor behind aneurotrophic joint.

TostudytheEfficacyofMRIspineexamincorrectlydiagnosingSpinallesionsinpatientspresentingwithaneurotrophicjoint

Study area

The study was carried out in the Department of Radiodiagnosis, S.B.K.S. Medical Institute and Research Centre, Waghodia, Vadodara.

Study design

Type of  the study:   An Observational, Descriptive Hospital Based Study.

Samplesize: 30patients.

Selection of subjectInclusioncriteria

• Only the willing patients were included to participatein study.
• Patients which were referred to the radiology department fore valuation no fneurotrophic joint but giving no history of underlying spinallesions were selected.
• Patients coming for investigations for other diseases, and were accidentally found to haven eurotrophic joint were included in this study.

Exclusioncriteria

• All un willing patients were excluded from this study.

Studyprotocol

30 patients which comprised of male as well as female patients, where, either the patient presented with deformity, disability ordestruction of one or multiple joints were firste valuated by plainradiograph study of the affected joint and a diagnosis of neurotrophic joint wasmade from the dedicated radiographs, or the patient presented with some other complaints and were incidentally found to have neurotrophic joint. All of the above patients were subjected to MRI Spine scan irrespective of them experiencing or notexperiencing complaints because of a spinal lesion.

Atotal30patientswereexaminedwithplainradiographsandMRIspine.

The salient observations are as follows

• In my study neurotrophic joint is more common in males (66.6%) than in females (33.3%) which were a ratio of2:1.
• The result of MRI spine conducted on the above 30 patients came out normal in12(40%) patients and findings were present in 18(60%) patients.
• Diagnosis on MRI spine was as follows: Syringomyeliain6 (20%) patients, Meningomyelocele in 5 (15%) patients, Arnold-Chiarimal formation in4 (15%) patients, and Arterio-venousmalformationin2(5%) patient and Syphillis in 1(5%) patient.
• In my study the upper limb was involved in 20(65%) patients and lower limb in10(35%) patients.
• The most common joint involved knee joint–in30%patients, followed by shoulder joint and hip joint–eachin20%patientsandleastcommonlyinvolved joints were elbow joint, ankle joint and foot joints–in15% patients.

Neuropathic arthropathy (Charcot joint) can bede fined as bone and joint changes that occur secondary to loss of sensation and that accompany a variety of disorders. There are two forms of Charcot joint- atrophic and hypertrophic. Charcot joint saretypically unilateral but are bilateral in ~20% (range 5.9-39.3%) of cases [5].

Common Causes include: Syphilis, Steroid use, Syringomyelia, Spinal cord injury, Spina bifida, Meningomyelocele, Leprosy, Scleroderma.

Thei nvolved jointis highly suggestive of the aetiology: [6]

Wrist:diabetes,syringomyelia

Hip: alcohol, tabesdorsalis

Knee:tabesdorsalis, congenitalinsensitivitytopain

AnkleandFoot:diabetes

Spine: spinalcord injury, diabetes, tabes dorsalis

Clinicalpresentation

Patientstypicallypresent insidiouslyorareidentifiedincidentallyorasaresultofinvestigationfordeformity.Unlikesepticarthritis,Charcotjointsalthough swollenarenormaltemperaturewithoutelevatedinflammatory   markers.    Importantly     theyarepainless.

Radiographicfeatures

Densebones(subchondralsclerosis,degeneration,destructionofarticularcartilage,deformity (pencil-point deformity of metatarsalheads),debris (loosebodies), dislocation.

Diagnosis onMRI

Syringomyleia- Syringomyelia is the development of afluid-filled cavityorsyrinx within the spinal cord. Peripheralneuropathic joints or even neuropathic alteration of the spineit self may developinlong- standing cases of syringomyelia. An atrophic form with resorption of the proximal humerus is described frequently in syringomyelia.

Arterio-venousmalformation-Spinalarteriovenousmalformations(AVMs)areabnormalcollectionsofbloodvesselsinthespinalcanalthathaveadirectconnectionbetweenthearterialsystemandthevenoussystemwithoutinterveningcapillaries.AVMsaccountforabout4percentofprimaryintraspinalmasses.Symptomsinvolveprogressive neurological symptoms over months to years, especially back pain as sociated with progressivesen sory loss and lower extremity weakness. 10 percent to 20 percent in volveasudden on set of weakness, numbness, difficulty urinating, urinaryincontinence, fecalincontinence, orparalysis (usually in patients younger than30) as a result of hemorrhage.

Arnold-Chiari malformation – These are a group of defects associated with congentialcaudald is placement of the cere bellum and brainstem.

Tabesdorsalis-It is a form of tertiaryneurosyphil is in which there is demyelination of the posterior columns of the spinal cord. Patientspresentwithsymptomsrelatedtodorsalcolumn/nerve-rootinvolvementsuchasweakness,sensoryataxia(tabeticgait),lancinatingpain,hypoesthesia,personalitychanges. It has the longest latent period of any neurosyphilis between primary infection and onsetofsymptoms, averaging about 20 years. Radiologically, it can man if estasa Charcot joint

(neuropathic arthropathy), usually involving the hip, the knee or the spine.

A substantial number of neurotrophic joints are caused secondary to lesions of the spine. Many a times the patient does not give any history ndicating as pine lesion .Hence MRI scan of Spine should be made a part of the investigations in every case of neurotrophic joint. It helps to accurately diagnoseavariety of spinal lesions and tells about its exact size, extent and severity and there by contributes immensely in the management of aneurotrophic joint.

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4. AhmadiME,MorrisonWB,CarrinoJA, et al. Neuropathic arthropathy ofthe foot  with  and withoutsuperimposedosteomyelitis:MRimagingcharacteristics.Radiology,2006; 238(2):622-31.
5. TanPL,Teh J. MRI ofthediabeticfoot: differentiation of infection fromneuropathicchange.BrJRadiol.,2007; 80(959):939-48.
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