Leprosy (Hansen’s disease) is a chronic granulomatous infectious disease which has plagued man since before the beginning of recorded history.

Studies have shown the appearance of the illness stretching back well over 4,000 years ago in India [1].  The disease has been mentioned in numerous texts, including the Bible (Exodus 4:6) [2].

Leprosy is caused by Mycobacterium Leprae and Mycobacterium Lepromatosis.  In 1873, Dr. G.A. Hansen was credited with the discovery of Mycobacterium Leprae, but as recently as 2008, Mycobacterium Lepromatosis was also found to be a causative agent of the disease.  These bacterium are thought to be aerobic, acid fast, gram positive, rod shaped bacillus in nature.  They typically thrive in tropical climates [3-5].  The bacteria is an obligate intracellular parasite inhabiting and replicating within macrophages, endothelial cells, and schwann cells of the peripheral nervous system.  The bacterium is not able to be grown in artificial media [6].

Transmission is unclear and in many cases under dispute.  Transmission is difficult, and is thought to occur through the mucosa of the respiratory or alimentary tracts through inhalation or ingestion, via prolonged skin to skin contact (possibly through micro abrasions), through insect bites, and via trans-placental transmission in rare cases [7, 8].   It is speculated that in nasal secretions, Mycobacterium leprae can survive up to 36 hours or more outside of a biological host in non-tropical conditions [9], and up to 9 days under tropical conditions [10].  Thus, fomites are also thought to act as a source of infection.  The incubation period ranges from 6 months to 40 years or longer, but on average 2 to 3 years [10, 11].  Symptoms can take up to 20 years to appear in infected individuals at times [12].

Leprosy manifests itself in different forms.  Via laboratory methods with the use of skin smears from infected individuals, leprosy can be categorized as either paucibacillary leprosy (PB) or multibacillary leprosy (MB) [12].  This classification system is used to determine the course of treatment for the infected individual.  In clinical practice, leprosy can be classified by its numerous presentations, as either lepromatous, borderline, borderline tuberculoid, tuberculoid, mid-borderline cases, indeterminate, or polar leprosy.  Diagnosis can be made in the field, based on clinical presentations but definite diagnosis is best made with the use of skin smears from infected individuals and histopathological studies [13].  Different manifestations of the condition occur at different rates in different individuals and in different regions of the world.  For example, adult men tend to have a higher prevalence of the lepromatous type of leprosy verse women [12], but children appear to present with the tuberculoid form more often [11]. 

If left untreated for long enough, it may cause permanent damage to the limbs, skin, vasculature, nerves, and eyes.  These symptoms are progressive, drastically increasing in severity if left untreated.  Throughout history, leprosy has brought upon its victims stigmatization and ostracization.  This is in part due to the physical deformities caused by the disease [14].  These emotions culminated in 1881 in India when the central government passed the Lepers Act of 1898, giving legal provision for forcible confinement of leprosy sufferers in India [15].

Clinical presentations of Hansen's disease reflect three aspects of the illness which include; bacterial proliferation, bacterial accumulation, and the host immunologic responses to bacillary antigens causing damage to the patient.  The bacterium has an affinity for the cooler temperatures of the peripheral nerves.  This explains the majority of the manifestations appearing in the extremities and the resulting peripheral neuritis [5]. 

In leprosy, pyogenic organisms readily enter through lesions in the skin.  This may lead to abscesses and resultant treatment of bone, joint, and tendon sheath infections.  The body becomes anesthetic due to the destruction of sensory fibers contained within the peripheral nerves, therefore making the affected areas prone to the injuries that result in open wounds and ulcerations.  Due to the loss of sensation the leprosy patient is not aware of self incurred injuries, leading to neglect of surface injuries which progresses to ulcerations and infections.   Motor fiber destruction leads to paralysis, wasting &contractures of muscles, and extremity deformation.  Most peripheral nerves are considered “mixed” (containing both sensory and motor nerve fibers) thus these events occur simultaneously.  The end result is that the limbs become anesthetic, ulcerated, possibly infected, paralyzed, and deformed [16].  Deformities such as claw hand and drop foot are common.  Foot drop is due to paralysis of the lateral popliteal nerve, where it winds round the neck of the fibula.  This causes some or all of the muscles of the anterior and lateral compartments to become paralyzed, therefore causing a “drop foot” [17].  “Clawed Hand” results from Ulnar, Median and/or Radial Nerve paralysis.  Wasting is seen in the hypothenar eminence in the thumb web and between the metacarpals.  Paralysis of the dorsal interossei results in failure of abduction of the fingers.  The Median Nerve is usually affected, where it is cooler (near the surface) just proximal to the wrist joint [18].

The progressive accumulation of anesthesia, ulcers, contractures and deformities leads to many complications.  These include a feeling of hopelessness and disability by the patient, leading to an ever growing state of emotional distress.  The constant open ulcerations also create a nidus for possible infection.  This may result in ulcers needing septic surgery.  Under such conditions amputation is indicated in leprosy.  In order to have a positive outcome, the amputation should be managed and supported by prosthetic devices.  85% of amputations in lepers are in the lower extremities, due to long-standing consequences of plantar ulcers and severe bone and joint disintegration [19]. 

Neural surgery is also an option for some leprosy patients, although it is rarely done.  Attempts to restore autonomic function and sensation are seldom performed because evidence lacks to prove that autonomic function can be significantly regained through such procedures.  Some physicians choose to drain acute nerve abscesses and perform fascicular dissection, which are regarded as “nerve decompression surgeries”.  These can reduce the pressure on nerves and has been shown to improve extremity sensation in some circumstances.  In some cases, longitudinal epineurotomy, neurovascular decompression via release of the flexor retinaculum, and calcaneal band slits have also shown some promise in regaining nerve function.  In the case of leprosy, neurological surgery can also be used with some patients who complain of unremitting nerve pain [20].

Neuritis and ulcerations of the skin lead to numerous lesions which call for reconstructive and plastic surgery.  For example, gross deformation of the nasal skeleton is not uncommon.  This may lead to subsequent formation of a classical “saddle-nose deformity”.  Surgical reconstruction of the nose, due to lesions caused by the disease, are troublesome for physicians to treat [21].  Other reconstructive and plastic surgery procedures include skin grafts, removal of excess skin, replacement of eyebrows using transplants of scalp hair, and removal of breast tissue formation due to gynecomastia induced by leprosy [20].

Numerous complications of the globe exist in lepers.  The invading bacteria may lead to enucleation when the globe becomes infected.  It is not uncommon to experience paralysis of the facial nerve with lagophthalmos (so that the eye cannot be closed) and loss of sensation in the ophthalmic division of the fifth cranial nerve (making the cornea anesthetic).  Many lepers also experience acute and chronic iritis and uveitis, causing atrophy of the dilator pupillae and an unreactive pupil [16].  In leprosy, the loss of eyelid function has been treated in the past by passing a strip of muscle from the temporalis muscle through the eyelid, thus connecting it to the inner canthus.  Tarsorrhaphy have been shown to help in cases where narrowing of the eyelid is needed.  Canthoplasty procedures reduce sagging of the eyelids [20].  It is apparent that ophthalmology based complications lead to numerous surgical treatment options in leprosy.

Due to the accumulation of various lesions as a result of Hansen’s disease, varying levels of functional deficits may occur in the performance of the activities of daily living (ADLs).  The deficits and disabilities are typically quantified by use of what is known as the World Health Organization (WHO) Disability Grading System,  “SALSA Scale” (measuring activity limitation) and Safety Awareness Score (indicating an  increasing awareness of the risks of certain activities) [12, 22].


Long-term use of medication allows for afflicted individuals to enter a noninfectious state, where they do not transmit the disease causing organism [23].  Leprosy is curable and when treatment is provided in the early stages, disability may be averted [12].  World-wide support has grown for the use of WHO recommended MDT (Multi Drug Therapy) which is Dapsone, Rifampicin, and Clofazimine.  Mycobacterium leprae can be resistant to these medications individually; therefore they are used in combination to combat resistant strains.  Since the implementation of MDT by the WHO in the 1980s, the world-wide number of individuals suffering from leprosy has dropped from a staggering 5.4 million to a currently estimated 212,802 globally [12, 24].

Although the disease has been shown throughout history to affect individuals on every continent, Hansen’s disease is more often found in rural areas with tropical climates [11].  It is most particularly prevalent in Angola, Brazil, Central African Republic, The Congo, Madagascar, Mozambique, Nepal, Tanzania, and India [12].   India in the 1990’s, was credited as the home of 75% of the world’s leprosy cases, and despite aggressive treatment of the disease the country is still home to the largest number of leprosy patient on earth [25].

The disease has not been shown to be limited to any particular age, sex, or race.  A 3 week old infant was proven to have the disease, with trans-placental transmission as a hypothesized mode of transmission, although, the disease is rare in infants.  Individuals over the age of seventy are also able to contract leprosy [12].  Although all age groups are susceptible, certain groups are more prone than others.  The young are at particularly higher risk.  Children less than 15 years have significantly higher risk than adults. “Maximum risk groups” in regards to children are considered to be boys in the age-group of 5-14 years, and females in the age-group of 5-9 years.  A bimodal age distribution exists with leprosy, with peak age groups of 10–14 and 35–44 years of age [20, 26, 27].  The sexes also have differences in distribution.  Adults show as much as 2:1 in male-to-female ratio for some forms of the disease.  Male preponderance is not uniform for all forms of the disease or certain regions of the globe.  Particular regions display equal occurrence of leprosy in both sexes or else a higher prevalence among females [12].

Many of the proposed pathological mechanisms of leprosy and vast majority of the pathological sequela has proven to be orthopedic in nature.  The disease is not typically thought of as being orthopedic in scope, but the effects are devastating.  Musculoskeletal debility and complications makes the disease of leprosy a key region of interest to the well trained orthopedic surgeon.

1.            Holden, C., Skeleton Pushes Back Leprosy's Origins, in Science Now. 2009.

2.            The Holy Bible. Vol. New International Verision. 1983, New York: Harper.

3.            Sasaki, S., et al., Mycobacterium leprae and leprosy: a compendium. Microbiol Immunol, 2001. 45(11): p. 729-36.

4.            Han, X.Y., et al., A new Mycobacterium species causing diffuse lepromatous leprosy. Am J Clin Pathol, 2008. 130(6): p. 856-64.

5.            Medical Microbiology. 4th ed, ed. S. Baron. 1996, Galveston, TX: The University of Texas Medical Branch at Galveston.

6.            Barker, L.P., Mycobacterium leprae interactions with the host cell: recent advances. Indian J Med Res, 2006. 123(6): p. 748-59.

7.            van Beers, S.M., M.Y. de Wit, and P.R. Klatser, The epidemiology of Mycobacterium leprae: recent insight. FEMS Microbiol Lett, 1996. 136(3): p. 221-30.

8.            Abraham, S., et al., Epidemiological significance of first skin lesion in leprosy. Int J Lepr Other Mycobact Dis, 1998. 66(2): p. 131-9.

9.            Davey, T.F. and R.J. Rees, The nasal dicharge in leprosy: clinical and bacteriological aspects. Lepr Rev, 1974. 45(2): p. 121-34.

10.         Desikan, K.V., Viability of Mycobacterium leprae outside the human body. Lepr Rev, 1977. 48(4): p. 231-5.

11.         Hussain, T., Leprosy and tuberculosis: an insight-review. Crit Rev Microbiol, 2007. 33(1): p. 15-66.

12.         Leprosy elimination. 2011, World Health Organization.

13.         Anuja Sharma, R.K.S., K C Goswsami, Subash Bardwaj, Clinico-Histopathological Correlation in Leprosy. JK SCIENCE, 2008. 10(3).

14.         Lifting the stigma of leprosy: a new vaccine offers hope against an ancient disease. Time, 1982. 119(19): p. 87.

15.         Chronological List of Central Acts, Ministry of Law and Justice: New Delhi, India.

16.         Nelson Awori, A.B., Alan Beasley, James Boland, Michael Crawford, Frits Driessen, Allen Foster, Wendy Graham, Brian Hancock, Branwen Hancock, Gerald Hankins, Neville Harrison, Ian Kennedy, Julius Kyambi, Samiran Nundy, Joe Sheperd, John Stewart, Grace Warren, Michael Wood Primary Surgery. Non-trauma, ed. P.C.B. Maurice King, James Cairns, Jim Thornton. Vol. 1. 1999: Deutsche Gesellschaft für Internationale Zusammenarbeit.

17.         Andersen, J.G., Foot Drop in Leprosy and its Surgical Correction. Acta Orthopaedica, 1963. 33(1-4): p. 151-171.

18.         Anderson, G.A., The surgical management of deformities of the hand in leprosy. J Bone Joint Surg Br, 2006. 88(3): p. 290-4.

19.         Virmond, M., Amputations in leprosy. Lepr Rev, 2007. 78: p. 85-87.

20.         Darvin Smith, T.R., Leprosy, in eMedicine: Infectious Disease. 2008.

21.         Shah, A.R., D. Zeitler, and J.B. Wise, Nasal reconstruction of the leprosy nose using costal cartilage. Otolaryngol Clin North Am, 2009. 42(3): p. 547-55.

22.         van Veen, N.H., et al., Evaluation of activity limitation and social participation, and the effects of reconstructive surgery in people with disability due to leprosy: a prospective cohort study. Disabil Rehabil. 33(8): p. 667-74.

23.         Leprosy, in U.S. National Library of Medicine, J.M.V. Linda Vorvick, David Zieve, Editor. 2011, U.S. Department of Health and Human Services: Bethesda, MD.

24.         Noordeen, S.K., Elimination of leprosy as a public health problem: progress and prospects. Bull World Health Organ, 1995. 73(1): p. 1-6.

25.         Report of the Global Forum on Elimination of Leprosy as a Public Health Problem. 2006. Geneva, Switzerland: World Health Organization.

26.         Rao, P.S., et al., Transmission of leprosy within households. Int J Lepr Other Mycobact Dis, 1975. 43(1): p. 45-54.

27.         Epidemiology of Leprosy in Relation to Control. 1985, World Health Organization: Geneva, Switzerland.

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