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Tripartite Fracture of the Ulnar Sesamoid Bone of the Thumb
The Journal of Emergency Medicine, Vol. -, No. -, pp. 1–2, 2017 Ó 2017 Elsevier Inc. All rights reserved. 0736-4679/$ - see front matter
http://dx.doi.org/10.1016/j.jemermed.2017.08.020
Visual Diagnosis in Emergency Medicine
TRIPARTITE FRACTURE OF THE ULNAR SESAMOID BONE OF THE THUMB Dunya N. Alfaraj, MD and Gary M. Vilke, MD Department of Emergency Medicine, UC San Diego Health System, San Diego, California Reprint Address: Dunya N. Alfaraj, MD, Department of Emergency Medicine, UC San Diego Health System, 200 West Arbor Drive, San Diego, CA 92103
hand identified tenderness over the base of the right thumb at the palmar aspect of the hand, with minimum soft-tissue swelling. Passive and active ranges of movement of interphalangeal and MCPJs were normal. Distal neurovascular was intact. No joint instability was noted. Anteroposterior digital x-ray study of the right hand (Figure 1) and its blown-up version (Figure 2) revealed tripartite fracture of the sesamoid bone at the ulnar side of the pollex MCPJ. The patient was treated with immobilization with a thumb spica splint and planned for follow-up.
INTRODUCTION Sesamoid fractures and dislocations are rare, and publications about them are typically case reports or small series. Fracture through a single sesamoid bone of the pollex has rarely been reported and its exact incidence is still uncertain, on the basis of unspecific clinical signs and equivocal radiologic findings (1,2). We report a case of a patient with a tripartite fracture of the ulnar-sided pollex metacarpophalangeal joint (MCPJ) sesamoid, to increase sensitivity and observation regarding this fracture because it is possible for a fracture of the sesamoid not to be detected in the absence of clinical suspicion or adequate radiologic views. The diagnosis and correct management of this fracture should be emphasized, as sesamoid arthritis of the MCPJ is a known consequence of trauma to the thumb, as is posttraumatic sesamoiditis, a chronic disabling thumb pain, which at times can only be managed successfully by sesamoidectomy (3,4).
DISCUSSION Sesamoid bones are usually round or oval-shaped bones, a few millimeters in diameter. Most people have five sesamoid bones in each hand. Two at the pollex MCPJ, one at the interphalangeal joint of the thumb, one at the MCPJ of the index finger, and one at the MCPJ of the little finger (5). The sesamoid bones are the part of a gliding mechanism that reduces friction and protects the tendon. Our case represents a fracture of the ulnar side of the sesamoid bone of the thumb. The most frequent mechanism of this injury is a violent hyperextension of the thumb. A fracture can be caused also by a violent abduction of the thumb, and less frequently from direct trauma. The digital radiographs are the diagnostic modality of choice. In conventional postero-anterior radiologic views, these fractures often remain occult, especially if
CASE REPORT A 55-year-old female helmeted bicycle rider arrived to the emergency department complaining of pain at the base of the right thumb after she fell off her bike to her right side when handle bars locked and her thumb was hyperextended. She was going 8–10 mph. Her medical history was noncontributory. Examination of the right
RECEIVED: 14 March 2017; FINAL SUBMISSION RECEIVED: 29 May 2017; ACCEPTED: 8 August 2017 1
2
Figure 1. Anteroposterior digital x-ray of right hand revealed tripartite fracture of the sesamoid bone at the ulnar side of the pollex metacarpophalangeal joint (arrow).
an oblique view is not obtained and the fragments are small. Computed tomography scan and magnetic resonance imaging are highly reliable diagnostic modalities, but they share some limitations in terms of immediate availability and high expenditure. Ossification may occur from multiple centers, which may not unite and can give a bipartite appearance of the sesamoid. Fractures of the sesamoids should be distinguished from such bipartite sesamoids. The edges of the bipartite sesamoids are smooth radiographically and the opposite thumb may show a similar bipartite sesamoid. The fractured fragments have usually irregular margins. In our case, the patient’s right ulnar-sided MCPJ sesamoid was tripartite, had irregular margins with clinically correlated tenderness directly over the region, indicating an acute fracture rather than normal variant. Sesamoid fractures are sometimes associated with tears of the volar plate ligament of the MCPJ. Patel et al. classified these injuries into types I and II, according to whether there was volar plate rupture (type II) or not (type I). Our case was a type I injury. Failure to recognize type II injury may lead to long-term hyperextension instability on pinching (2). Treatment is generally non-surgical, with a functional taping or static splinting during 2–3 weeks. In case of associated and complete volar plate rupture, dorsal blocking
D. N. Alfaraj and G. M. Vilke
Figure 2. Blown-up version of the anteroposterior digital xray of right hand demonstrated tripartite fracture of the sesamoid bone at the ulnar side of the pollex metacarpophalangeal joint obviously (arrow).
splint is recommended, allowing normal MCP flexion but limited extension for 3 weeks. Finally, in the case of continued pain after conservative treatment, removal of the sesamoid is reported via sesamoidectomy. In most cases the prognosis is very good, with full recovery of the function and recession of pain. In conclusion, the diagnosis of fractures of the sesamoids of the pollex MCPJs is established with high clinical suspicion and adequate radiologic view. The detection and correct management will prevent posttraumatic sesamoiditis, chronic pain, and long-term hyperextension instability on pinching. REFERENCES 1. Ozcanli H, Sekerci R, Keles N. Sesamoid disorders of the hand. J Hand Surg 2015;40:1231–2. 2. Deabate L, Garavaglia G, Lucchina S, et al. Fracture of the radial sesamoid bone of the thumb: an unusual fracture. Chin J Traumatol 2011;14:309–11. 3. Fotiadis E, Samoladas E, Akritopoulos P, et al. Ulnar sesamoid’s fracture of the thumb: an unusual injury and review of the literature. Hippokratia 2007;11:154–6. 4. Connolly CM, Alsousou J, Hassan S, et al. Don’t avoid the sesamoids: fracture to the ulnar sesamoid of the first metacarpophalangeal joint. Emerg Med J 2008;25:184. 5. Wood VE. The sesamoid bones of the hand and their pathology. J Hand Surg Br 1984;9:261–4.
http://dx.doi.org/10.1016/j.jemermed.2017.08.020
Visual Diagnosis in Emergency Medicine
TRIPARTITE FRACTURE OF THE ULNAR SESAMOID BONE OF THE THUMB Dunya N. Alfaraj, MD and Gary M. Vilke, MD Department of Emergency Medicine, UC San Diego Health System, San Diego, California Reprint Address: Dunya N. Alfaraj, MD, Department of Emergency Medicine, UC San Diego Health System, 200 West Arbor Drive, San Diego, CA 92103
hand identified tenderness over the base of the right thumb at the palmar aspect of the hand, with minimum soft-tissue swelling. Passive and active ranges of movement of interphalangeal and MCPJs were normal. Distal neurovascular was intact. No joint instability was noted. Anteroposterior digital x-ray study of the right hand (Figure 1) and its blown-up version (Figure 2) revealed tripartite fracture of the sesamoid bone at the ulnar side of the pollex MCPJ. The patient was treated with immobilization with a thumb spica splint and planned for follow-up.
INTRODUCTION Sesamoid fractures and dislocations are rare, and publications about them are typically case reports or small series. Fracture through a single sesamoid bone of the pollex has rarely been reported and its exact incidence is still uncertain, on the basis of unspecific clinical signs and equivocal radiologic findings (1,2). We report a case of a patient with a tripartite fracture of the ulnar-sided pollex metacarpophalangeal joint (MCPJ) sesamoid, to increase sensitivity and observation regarding this fracture because it is possible for a fracture of the sesamoid not to be detected in the absence of clinical suspicion or adequate radiologic views. The diagnosis and correct management of this fracture should be emphasized, as sesamoid arthritis of the MCPJ is a known consequence of trauma to the thumb, as is posttraumatic sesamoiditis, a chronic disabling thumb pain, which at times can only be managed successfully by sesamoidectomy (3,4).
DISCUSSION Sesamoid bones are usually round or oval-shaped bones, a few millimeters in diameter. Most people have five sesamoid bones in each hand. Two at the pollex MCPJ, one at the interphalangeal joint of the thumb, one at the MCPJ of the index finger, and one at the MCPJ of the little finger (5). The sesamoid bones are the part of a gliding mechanism that reduces friction and protects the tendon. Our case represents a fracture of the ulnar side of the sesamoid bone of the thumb. The most frequent mechanism of this injury is a violent hyperextension of the thumb. A fracture can be caused also by a violent abduction of the thumb, and less frequently from direct trauma. The digital radiographs are the diagnostic modality of choice. In conventional postero-anterior radiologic views, these fractures often remain occult, especially if
CASE REPORT A 55-year-old female helmeted bicycle rider arrived to the emergency department complaining of pain at the base of the right thumb after she fell off her bike to her right side when handle bars locked and her thumb was hyperextended. She was going 8–10 mph. Her medical history was noncontributory. Examination of the right
RECEIVED: 14 March 2017; FINAL SUBMISSION RECEIVED: 29 May 2017; ACCEPTED: 8 August 2017 1
2
Figure 1. Anteroposterior digital x-ray of right hand revealed tripartite fracture of the sesamoid bone at the ulnar side of the pollex metacarpophalangeal joint (arrow).
an oblique view is not obtained and the fragments are small. Computed tomography scan and magnetic resonance imaging are highly reliable diagnostic modalities, but they share some limitations in terms of immediate availability and high expenditure. Ossification may occur from multiple centers, which may not unite and can give a bipartite appearance of the sesamoid. Fractures of the sesamoids should be distinguished from such bipartite sesamoids. The edges of the bipartite sesamoids are smooth radiographically and the opposite thumb may show a similar bipartite sesamoid. The fractured fragments have usually irregular margins. In our case, the patient’s right ulnar-sided MCPJ sesamoid was tripartite, had irregular margins with clinically correlated tenderness directly over the region, indicating an acute fracture rather than normal variant. Sesamoid fractures are sometimes associated with tears of the volar plate ligament of the MCPJ. Patel et al. classified these injuries into types I and II, according to whether there was volar plate rupture (type II) or not (type I). Our case was a type I injury. Failure to recognize type II injury may lead to long-term hyperextension instability on pinching (2). Treatment is generally non-surgical, with a functional taping or static splinting during 2–3 weeks. In case of associated and complete volar plate rupture, dorsal blocking
D. N. Alfaraj and G. M. Vilke
Figure 2. Blown-up version of the anteroposterior digital xray of right hand demonstrated tripartite fracture of the sesamoid bone at the ulnar side of the pollex metacarpophalangeal joint obviously (arrow).
splint is recommended, allowing normal MCP flexion but limited extension for 3 weeks. Finally, in the case of continued pain after conservative treatment, removal of the sesamoid is reported via sesamoidectomy. In most cases the prognosis is very good, with full recovery of the function and recession of pain. In conclusion, the diagnosis of fractures of the sesamoids of the pollex MCPJs is established with high clinical suspicion and adequate radiologic view. The detection and correct management will prevent posttraumatic sesamoiditis, chronic pain, and long-term hyperextension instability on pinching. REFERENCES 1. Ozcanli H, Sekerci R, Keles N. Sesamoid disorders of the hand. J Hand Surg 2015;40:1231–2. 2. Deabate L, Garavaglia G, Lucchina S, et al. Fracture of the radial sesamoid bone of the thumb: an unusual fracture. Chin J Traumatol 2011;14:309–11. 3. Fotiadis E, Samoladas E, Akritopoulos P, et al. Ulnar sesamoid’s fracture of the thumb: an unusual injury and review of the literature. Hippokratia 2007;11:154–6. 4. Connolly CM, Alsousou J, Hassan S, et al. Don’t avoid the sesamoids: fracture to the ulnar sesamoid of the first metacarpophalangeal joint. Emerg Med J 2008;25:184. 5. Wood VE. The sesamoid bones of the hand and their pathology. J Hand Surg Br 1984;9:261–4.