Isolated Pathological Fracture o f the Cap#ate Bone. A Case Report Carl D. Enna
I S O L A T E D P A T H O L O G I C A L F R A C T U R E OF T H E C A P I T A T E BONE A Case Report CARL D. ENNA, Carville, Louisiana SUMMARY Isolated fracture of the capitate bone is rare, but an isolated pathological fracture due to leprosy has not been previously reported. Although varying degrees of trauma is implied to be associated with fractures, this case illustrates a pathological fracture o f the capitate apparently due solely to a specific disease. Fracture has occurred without a history of trauma and there has been no displacement of the fragments on x-rays over a period exceeding ten years even though it has been subjected to unrestricted activities by the patient who has clinically inactive disease.
INTRODUCTION Varying degree of forces, either sudden and severe, or an accumulation of repetitive stresses are usually incriminated as producing pathological fractures. Where ever differentiation between apparently normal and diseased bone is usually lacking, such factors as osteogenic abnormaXity, bone pathology due to neoptasia and infection, and fatigue can lead to decreased resistance and greater vulnerability to injury (Adler, 1962; Vizkelety, 1972). The report of this case is warranted not only due to the rarity o f an isolated fracture of the capitate bone, but because of the absence of a report in the literature of a pathological fracture due solely to a specific infection and no known implication by trauma. CASE REPORT The patient is a forty-three year old Caucasian male in hospital with the diagnosis of active lepromatous leprosy and recurring episodes of erythema nodosum leprosum (ENL) reactions. During an episode of ENL, the left middle finger became involved with diffuse reaction evident by fusiform swelling and generalised redness. Radiographs of the hand, which did not include the carpus, revealed osteolytic changes involving the metaphysis of the left second and third metacarpal bones. The patient responded to specific drug therapy with the osteolytic lesions of the metacarpal bones resolving despite the omission of splinting of the digits for protection. Follow-up radiographs o f the hand, which included the carpus, revealed a pathological fracture of the capitate and residual changes of healed osteitis in the second and third metacarpal bones (Fig. 1). The pathological fracture of the left capitate bone, in retrospect, was considered to have existed concomitantly with the initial changes that involved the metacarpal bones. Subsequent annual routine radiographs o f the hands have shown no significant interval change in this fracture. This patient has been living a normal life with unrestricted activities for a period exceeding ten years, yet the radiographic changes of the capitate have persisted and have remained constant. DISCUSSION Questions may be raised as to what constitutes a pathological fracture, how does it differ from stress fracture, and in what ways is stress related to the Carl D. Enna, MD, FACS, USPHS Hospital, Carville, Louisiana, 70721, U.S.A. The Hand-- Volume t l
No. 3
1979
329
Isolated Pathological Fracture o f the Capitate Bone. A Case Report Carl D. Enna
Fig. 1. (A) Normal admission radiograph of hands. (B) Osteolvticchanges involvingthe heads of the second and third metacarpals. (C) Pathological fracture of the capitate and almost complete resolution of osteolyticchanges of the metacarpals. pathological fracture of this case? Fracture is defined as an interruption in the continuity of bone, and trauma is generally inferred and is taken for granted to be the cause of a fracture. However, it does not appear to be an absolute requirement as demonstrated in this case. Leprosy, a specific disease, is incriminated as the only probable cause o f the pathological fracture of the capitate bone. This opinion is derived from the observation of constant radiographic changes of the gross configuration of the capitate bone retained without deformity over a period exceeding ten years. A review of the gross anatomy and the circulation of the capitate, correlated with the disease process due to leprosy, provides a better understanding how the development of the fracture could result solely from the disease process. The capitate presents a rounded head proximally, with a constricted intervening portion, the neck, and a broad body distally. It is the largest carpal bone, and is located centrally in the distal carpal row, possessing extensive articular surfaces for seven bones. It is considered as occupying a keystone position due to its alignment with the anatomical axis of the hand and wrist. The body of the capitate is fixed to the bases of the second, third and fourth metacarpals, with lateral and medial support by the trapezoid and hamate respectively. The head articulating with the scaphoid and lunate maintains its alignment in the anatomical axis during ulnar and radial deviation of the wrist, and thus issubject to strain during movement (Bunnell, 1948). T r a u m a and disease of bone are often related to the circulation and this is particularly true in leprosy. The circulation of the capitate is variable with nutrient vessels entering the bone primarily at the neck, but also through ligamentous 330
The Hand--Volume 11
No. 3
1979
Isolated Pathological Fracture o f the Capitate Bone. A Case Report Carl D. Enna
attachments. The areas covered by articular cartilage receive their blood supply from vessels that ha~e entered the medullary bone especially at the cervical region (Laing, 1960). The development of leprous osteitis is cli~sely related to the circulation with involvement occurring in nearly every severe case. Patients with lepromatous leprosy have large numbers of Mycobacterium leprae in the marrow of the small bones in the hands and feet without radiographic evidence of osteitis (Gass, 1934). Leprous osteitis, on the other hand, is due to disease; however, its onset is often first apparent during ENL reactions, a clinical syndrome generally manifested by erythematous nodular skin eruptions and occasionally a painful neuritis, synovitis and osteitis among other findings. Histopathologically, ENL is characterised by vasculitis with infiltration by polymorphonuclear leucocytes. Radiographic evidence o f enlarged nutrient foramina exceeding 4 mm. in diameter is interpreted as indicating diseased vessels. Embolic and single bacilli are reported in the lumen and endothelium of vessels respectively, and especially within terminal vascular loops (Fite, 1941). The site of the greatest vascularity in the capitate is in the cervical region where the initiation of leprous osteitis would be expected to occur. The absorptive bone changes due to leprosy are attributed to the action o f acid hydrolases liberated from lysosomes of histiocytes containing M. leprae (Brieger, 1962). Destruction of bone has been correlated with an increase in the acid phosphatase lysozyme. (Enna, 1971). CONCLUSION
An isolated fracture of the capitate bone is rare and pathological fracture due solely to leprosy has not been previously reported. The mechanism by which the fracture is produced differs from fracture produced by trauma. The osteolytic changes attributed to leprosy are due to the direct action o f acid hydrolases liberated from lysosomes of macrophages associated with the M.leprae infection. This case illustrates a pathological fracture of the capitate due solely to a specific disease, in which trauma apparently is not a factor either causing or contributing to aggravation of the pathological lesion. REFERENCES ADLER, J. B. and SHAFTAN, G. W. (1962) Fractures of the Capitate. The Journal of Bone and Joint Surgery 44:1537-1547. BRIEGER, E. M. and ALLEN, J. M. 11962) Cytopathological Changes In Lepra Cells. Experimemal Cell Research, 28: 438-440. BUNNELL, S. Surgery of the Hand, 2nd Edition Philadelphia, London, J. B. Lippincon Company. 1948, p.34. ENNA, C. D., PRABHAKARAN, K. and HARRIS, E.. B. (1971) The Role of Lysosomes in Resorption of Bone. International Journal of Leprosy, 39: 54-59. FITE, G.L. (1941) The Vascular Lesions of Leprosy. International Journal of Leprosy. 9: 193-202. GASS, H. H. and RISHI, D. P. (1934) Examination of Bone Marrow For M.Leprae. Leprosy in India 6: 8. LAING, P. G. (1960) The Blood Supply of the Bones of the Forearm and Hand. Surgical Clinics of North America 40:311-320. VIZKELETY, T. and WOUTERS, H. W. Stress Fractures of the Capitate. Case Report. Archivum Chirurgicum Neerlandicum 24: 47-57, 1972. The Hand--Volume l l
No. 3
1979
331
I S O L A T E D P A T H O L O G I C A L F R A C T U R E OF T H E C A P I T A T E BONE A Case Report CARL D. ENNA, Carville, Louisiana SUMMARY Isolated fracture of the capitate bone is rare, but an isolated pathological fracture due to leprosy has not been previously reported. Although varying degrees of trauma is implied to be associated with fractures, this case illustrates a pathological fracture o f the capitate apparently due solely to a specific disease. Fracture has occurred without a history of trauma and there has been no displacement of the fragments on x-rays over a period exceeding ten years even though it has been subjected to unrestricted activities by the patient who has clinically inactive disease.
INTRODUCTION Varying degree of forces, either sudden and severe, or an accumulation of repetitive stresses are usually incriminated as producing pathological fractures. Where ever differentiation between apparently normal and diseased bone is usually lacking, such factors as osteogenic abnormaXity, bone pathology due to neoptasia and infection, and fatigue can lead to decreased resistance and greater vulnerability to injury (Adler, 1962; Vizkelety, 1972). The report of this case is warranted not only due to the rarity o f an isolated fracture of the capitate bone, but because of the absence of a report in the literature of a pathological fracture due solely to a specific infection and no known implication by trauma. CASE REPORT The patient is a forty-three year old Caucasian male in hospital with the diagnosis of active lepromatous leprosy and recurring episodes of erythema nodosum leprosum (ENL) reactions. During an episode of ENL, the left middle finger became involved with diffuse reaction evident by fusiform swelling and generalised redness. Radiographs of the hand, which did not include the carpus, revealed osteolytic changes involving the metaphysis of the left second and third metacarpal bones. The patient responded to specific drug therapy with the osteolytic lesions of the metacarpal bones resolving despite the omission of splinting of the digits for protection. Follow-up radiographs o f the hand, which included the carpus, revealed a pathological fracture of the capitate and residual changes of healed osteitis in the second and third metacarpal bones (Fig. 1). The pathological fracture of the left capitate bone, in retrospect, was considered to have existed concomitantly with the initial changes that involved the metacarpal bones. Subsequent annual routine radiographs o f the hands have shown no significant interval change in this fracture. This patient has been living a normal life with unrestricted activities for a period exceeding ten years, yet the radiographic changes of the capitate have persisted and have remained constant. DISCUSSION Questions may be raised as to what constitutes a pathological fracture, how does it differ from stress fracture, and in what ways is stress related to the Carl D. Enna, MD, FACS, USPHS Hospital, Carville, Louisiana, 70721, U.S.A. The Hand-- Volume t l
No. 3
1979
329
Isolated Pathological Fracture o f the Capitate Bone. A Case Report Carl D. Enna
Fig. 1. (A) Normal admission radiograph of hands. (B) Osteolvticchanges involvingthe heads of the second and third metacarpals. (C) Pathological fracture of the capitate and almost complete resolution of osteolyticchanges of the metacarpals. pathological fracture of this case? Fracture is defined as an interruption in the continuity of bone, and trauma is generally inferred and is taken for granted to be the cause of a fracture. However, it does not appear to be an absolute requirement as demonstrated in this case. Leprosy, a specific disease, is incriminated as the only probable cause o f the pathological fracture of the capitate bone. This opinion is derived from the observation of constant radiographic changes of the gross configuration of the capitate bone retained without deformity over a period exceeding ten years. A review of the gross anatomy and the circulation of the capitate, correlated with the disease process due to leprosy, provides a better understanding how the development of the fracture could result solely from the disease process. The capitate presents a rounded head proximally, with a constricted intervening portion, the neck, and a broad body distally. It is the largest carpal bone, and is located centrally in the distal carpal row, possessing extensive articular surfaces for seven bones. It is considered as occupying a keystone position due to its alignment with the anatomical axis of the hand and wrist. The body of the capitate is fixed to the bases of the second, third and fourth metacarpals, with lateral and medial support by the trapezoid and hamate respectively. The head articulating with the scaphoid and lunate maintains its alignment in the anatomical axis during ulnar and radial deviation of the wrist, and thus issubject to strain during movement (Bunnell, 1948). T r a u m a and disease of bone are often related to the circulation and this is particularly true in leprosy. The circulation of the capitate is variable with nutrient vessels entering the bone primarily at the neck, but also through ligamentous 330
The Hand--Volume 11
No. 3
1979
Isolated Pathological Fracture o f the Capitate Bone. A Case Report Carl D. Enna
attachments. The areas covered by articular cartilage receive their blood supply from vessels that ha~e entered the medullary bone especially at the cervical region (Laing, 1960). The development of leprous osteitis is cli~sely related to the circulation with involvement occurring in nearly every severe case. Patients with lepromatous leprosy have large numbers of Mycobacterium leprae in the marrow of the small bones in the hands and feet without radiographic evidence of osteitis (Gass, 1934). Leprous osteitis, on the other hand, is due to disease; however, its onset is often first apparent during ENL reactions, a clinical syndrome generally manifested by erythematous nodular skin eruptions and occasionally a painful neuritis, synovitis and osteitis among other findings. Histopathologically, ENL is characterised by vasculitis with infiltration by polymorphonuclear leucocytes. Radiographic evidence o f enlarged nutrient foramina exceeding 4 mm. in diameter is interpreted as indicating diseased vessels. Embolic and single bacilli are reported in the lumen and endothelium of vessels respectively, and especially within terminal vascular loops (Fite, 1941). The site of the greatest vascularity in the capitate is in the cervical region where the initiation of leprous osteitis would be expected to occur. The absorptive bone changes due to leprosy are attributed to the action o f acid hydrolases liberated from lysosomes of histiocytes containing M. leprae (Brieger, 1962). Destruction of bone has been correlated with an increase in the acid phosphatase lysozyme. (Enna, 1971). CONCLUSION
An isolated fracture of the capitate bone is rare and pathological fracture due solely to leprosy has not been previously reported. The mechanism by which the fracture is produced differs from fracture produced by trauma. The osteolytic changes attributed to leprosy are due to the direct action o f acid hydrolases liberated from lysosomes of macrophages associated with the M.leprae infection. This case illustrates a pathological fracture of the capitate due solely to a specific disease, in which trauma apparently is not a factor either causing or contributing to aggravation of the pathological lesion. REFERENCES ADLER, J. B. and SHAFTAN, G. W. (1962) Fractures of the Capitate. The Journal of Bone and Joint Surgery 44:1537-1547. BRIEGER, E. M. and ALLEN, J. M. 11962) Cytopathological Changes In Lepra Cells. Experimemal Cell Research, 28: 438-440. BUNNELL, S. Surgery of the Hand, 2nd Edition Philadelphia, London, J. B. Lippincon Company. 1948, p.34. ENNA, C. D., PRABHAKARAN, K. and HARRIS, E.. B. (1971) The Role of Lysosomes in Resorption of Bone. International Journal of Leprosy, 39: 54-59. FITE, G.L. (1941) The Vascular Lesions of Leprosy. International Journal of Leprosy. 9: 193-202. GASS, H. H. and RISHI, D. P. (1934) Examination of Bone Marrow For M.Leprae. Leprosy in India 6: 8. LAING, P. G. (1960) The Blood Supply of the Bones of the Forearm and Hand. Surgical Clinics of North America 40:311-320. VIZKELETY, T. and WOUTERS, H. W. Stress Fractures of the Capitate. Case Report. Archivum Chirurgicum Neerlandicum 24: 47-57, 1972. The Hand--Volume l l
No. 3
1979
331
