- Email: [email protected]
An Atypical Presentation of Hallucial Sesamoid Avascular Necrosis: A Case Report
An Atypical Presentation of Hallucial Sesamoid Avascular Necrosis: A Case Report Geraint Williams, MBCHB,1 Peter Kenyon, MBCHB,1 Benjamin Fischer, MBCHB,2 and Simon Platt, MBCHB3 Sesamoid bone disorders are a rare cause of metatarsal pain and can be difficult to diagnose. This article describes an atypical case of avascular necrosis of the fibular sesamoid in a 62-year-old male. Avascular necrosis of the sesamoid is an infrequent and incompletely defined process. The case described in this report is somewhat atypical as this condition is usually associated with female sex, adolescence, or a precipitating factor of minor trauma. Level of Clinical Evidence: 4. ( The Journal of Foot & Ankle Surgery 48(2):203–207, 2009) Key Words: avascular necrosis, case report, sesamoid bone
P edal sesamoid bone disorders are a rare cause of metatarsal pain, the diagnosis of which can be rather difficult to make. Once the diagnosis is made, moreover, the condition can be difficult to treat. Avascular necrosis (AVN) of the metatarsal sesamoids was first described by Renander, in 1924 (1), and the condition remains an infrequent and incompletely defined pathology of the hallux sesamoid bones. This report describes an atypical case of hallucial sesamoid avascular necrosis. Case Report A 62-year-old retired male engineer with a body mass index of 26 (overweight) (2), presented to our outpatient clinic with a 2-year history of pain under the base of his right great toe, which was aggravated by weight bearing, and he related no history of preceding trauma. The patient was a lifelong heavy smoker with suspected but unconfirmed peripheral vascular disease. His significant past med-
Address correspondence to Geraint Williams, MBCHB, ST2 Orthopaedics, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom CH49 5PE. E-mail: [email protected]. 1 ST2 Orthopaedics, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom. 2 FY2 Orthopaedics, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom. 3 Consultant Orthopaedic Surgeon, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom. Financial Disclosure: None reported. Conflict of Interest: None reported. Copyright © 2009 by the American College of Foot and Ankle Surgeons 1067-2516/09/4802-0017$36.00/0 doi:10.1053/j.jfas.2008.11.004
ical history included depression, diverticular disease, and a previous right leg deep vein thrombosis in the distant past. On presentation, simple observation of the patient’s gait revealed a reluctance to push off or sustain weight through the right great toe. An area of maximal tenderness was identified under the metatarsal head, and this site corresponded to the sesamoid bones of his right foot. Radiographic inspection demonstrated the presence and correct alignment of the sesamoids of the right first metatarsophalangeal joint (MTPJ); and the fibular sesamoid demonstrated an irregular shape and sclerosis that was suggestive of the presence of avascular necrosis (Figure 1). After 6 months of conservative management with custom orthotic devices, the patient related little improvement in regard to his symptoms, and he consented to an injection of 40 mg of triamcinolone acetonide mixed with 10 mL of 1% plain lidocaine. Image intensification was used to guide the needle between the metatarsal head and fibular sesamoid from a plantar approach. This procedure provided 3 days of total symptom relief, followed by a recurrence of symptoms. Steroid injection is not a recognized treatment for sesamoid bone necrosis but is often administered in the early stages of the disease as a relatively conservative measure before sesamoid excision and confirmatory histological diagnosis (3). A technetium (99Tc) bone scan demonstrated focal uptake in the region of his right first MTPJ, during the third phase of the scan (Figure 2). Magnetic resonance image (MRI) scans demonstrated a small, irregular fibular sesamoid with surrounding fat edema (Figure 3). T1-weighted coronal MRI scans demonstrated low signal intensity that was indicative of fibular sesamoid marrow edema (Figure 4). The combination of clinical findings, along with the diagnostic imaging studies and the lack of a history of direct trauma, suggested a diagnosis of AVN of the fibular sesamoid. VOLUME 48, NUMBER 2, MARCH/APRIL 2009
203
FIGURE 1 Anteroposterior radiographic view demonstrating irregular shape and sclerosis of the fibular sesamoid (arrow).
FIGURE 3 Anteroposterior T1-weighted MRI demonstrating a small, irregular fibular sesamoid with surrounding fat edema (arrows).
FIGURE 4 Coronal T1-weighted MRI demonstrating low signal intensity indicative of fibular sesamoid marrow edema (arrow).
FIGURE 2 A technetium (99Tc) bone scan demonstrating focal uptake in the region of his right first MTPJ (arrow).
In response to his unresolved symptoms and the suspected diagnosis of sesamoidal AVN, the decision was made to pursue excision of the fibular sesamoid through a small, curvilin204
THE JOURNAL OF FOOT & ANKLE SURGERY
ear, plantar incision over the first metatarsal head (Figure 5). The plantar nerve was identified and protected throughout the dissection. The fibular sesamoid was accessed through the flexor hallux brevis tendon, which was repaired with a continuous multifilament absorbable suture (Figure 6). The patient was discharged to his home on the same day as the surgery, with advice to bear weight and to ambulate to his tolerance.
FIGURE 6 The fibular sesamoid was accessed via retraction of the flexor hallux brevis tendons.
FIGURE 5 A small curvilinear, plantar approach was used to excise the fibular sesamoid.
Subsequent, histological examination of the excised fibular sesamoid verified bone necrosis (Figure 7), with micrographic (⫻10) evidence of a zone of transition from relatively healthy cortical bone with abundant viable osteoblasts, to necrotic bone devoid of viable osteoblasts and empty lacunae. Histological inspection also revealed the appearance of end-on capillaries traversing necrotic sections of bone, which was indicative of attempted revascularization (Figure 7). The specific histopathological features observed in the specimen related to this case report were consistent with a diagnosis of AVN of the fibular sesamoid bone (4). Twenty months after surgery, our patient’s gait pattern returned to normal and most of his symptoms had resolved. The patient did not display any clinical or radiographic evidence of hallux varus, despite having had his fibular sesamoid removed (Figures 8 and 9). He did, however, begin to develop intermittent discomfort in the region of the tibial sesamoid of the right first MTPJ, and this required occasional use of paracetamol and his orthotic insoles, and continues to maintain periodic follow-up examinations.
FIGURE 7 Microscopic inspection of the excised fibular sesamoid revealed a zone of transition from healthy cortical bone (A) with abundant viable osteoblasts, to necrotic bone (B) with empty lacunae devoid of viable osteoblasts, as well as end-on capillaries traversing necrotic sections of bone (C).
Discussion Osteonecrosis of the hallucial sesamoid bones is a relatively rare disorder, and the prevalence of this condition is unclear (5). The case described in this report was somewhat atypical, in that the condition is classically reported in females presenting in adolescence with a precipitating history of minor forefoot trauma (1, 4 – 6). Under normal conditions the hallucial sesamoids act as a fulcrum to increase mechanical force in the toe off phase of gait, and they are also thought to protect the MTPJ and the long flexor tendon to the hallux, as the tendon of flexor hallucis brevis and the sesamoids serve as shock absorbers plantar to the first metatarsal head (6, 7). As demonstrated by our patient, mechanically induced pain plantar to the first metatarsal on VOLUME 48, NUMBER 2, MARCH/APRIL 2009
205
FIGURE 8 At 20 months following excision of the fibular sesamoid, the weight-bearing clinical appearance of the right foot revealed no evidence of hallux varus.
FIGURE 9 Latest anteroposterior radiographic view demonstrating absence of fibular sesamoid following excision with no radiographic evidence of hallux valgus.
weight bearing is the foremost presenting symptom in patients with avascular necrosis of a hallucial sesamoid and, in this particular respect, our case was rather conventional. Sclerosis, flattening, and demineralization are classical radiographic findings of sesamoid AVN. Fragmentation into 2 or more pieces is also common, and a “bone dust” appearance due to a multitude of fragments can sometimes be seen radiographically (4, 5). Care should be exercised not to mistake ossification, which is complete between 9 and 14 years of age (8), for fragmentation. It should also be noted that a lag time of up to 6 months between the onset of symptoms and distinct radiographic change is not an unusual occurrence (9). Therefore, in the acute situation, other 206
THE JOURNAL OF FOOT & ANKLE SURGERY
imaging techniques should be considered if radiographs are normal and a diagnosis of AVN is suspected. Our patient presented after an approximately 2-year period of slowly worsening symptoms and, as such, it was not surprising that distinct radiographic changes were evident at that time. It has been postulated that bone scanning is most useful for early diagnosis, since increased technetium (99Tc) uptake in areas of revascularization and remodeling supersedes the onset of radiographic changes. However, decreased or no uptake may occur in the early stages of the necrotic process (4, 5). We feel that technetium bone scanning may not be as useful a diagnostic measure as previously suggested, since our case demonstrated equivocal findings using this technique after a prolonged symptomatic period. MRI is probably the single most useful noninvasive investigative modality, when osteonecrosis is being considered, because signal abnormalities become visible during the first few days of the osteonecrotic process and T1weighted sequences rapidly show replacement of fat and hematopoietic tissue with fibrosis (10). The pathophysiology of sesamoid avascular necrosis is unclear. Trauma leading to the disruption of the tenuous blood supply of the hallucial sesamoids has been postulated as a potential cause (1, 4 – 6, 11). The extraosseous blood supply to the sesamoids originates from a branch of the medial plantar artery, and the intraosseous supply is derived mainly from a single vessel that commonly enters the proximal aspect of each bone. Plantar vessels also penetrate the nonarticular surfaces of the sesamoids, and occasionally capsular vessels provide a minor contribution to the distal zone of each sesamoid. Despite this network of blood vessels, the hallucial sesamoids do not demonstrate the rich anastomotic ring of vessels that is required to maintain adequate perfusion after disruption of the primary intraosseous arterial supply (11). Because the onset of symptoms in the case described in this article was insidious, and there was no history of trauma, spontaneous osteonecrosis may have occurred secondary to a microvascular event that interrupted the primary blood supply to the fibular sesamoid. Our patient presented with the unusual finding of radiographic evidence of an abnormal fibular sesamoid, suggesting the diagnosis of AVN at the time of presentation to our practice. Bipartite and abnormally shaped hallucial sesamoids have been show to demonstrate variability in regard to vascular supply, wherein the blood supply enters either the proximal or distal pole of the ossicle (11). For this reason, treatment by means of partial sesamoidectomy, which has been recommended by some authors (12, 13), could result in necrosis of the remaining fragment of bone, and symptom recurrence. Because we were concerned about this potential problem in the patient described in this article, and because the MRI scans did not clearly localize the precise extent of the necrotic process, we felt that the best option for our patient was total excision of the pathological sesamoid.
Published literature regarding the management of sesamoid avascular necrosis suggests that patients follow an initial course of conservative treatment, followed by complete sesamoidectomy if the patient fails to satisfactorily respond to nonsurgical treatment efforts (1, 4 – 6). It should also be noted that, as was the case with the patient described in this article, removal of the entire lateral sesamoid could be followed by the development of increased pain localized to the medial (tibial) sesamoid. The development of pain plantar to the first metatarsal because of the absence of the fibular sesamoid is generally understood to be a relatively common complication of complete sesamoidectomy. This condition has been attributed to alteration of weight-bearing mechanical function around the metatarsal head, and to postsurgical scaring with neuromalike symptoms (14). Occasionally, patients may develop hallux varus following complete excision of the fibular sesamoid (15). The prevalence of these complications, as well as the optimal method of treatment, has not been thoroughly defined; and the use of analgesic medications and custom foot orthoses can be helpful, as was the case with the patient described in this report. Future investigations into the prevalence of hallucial sesamoid AVN, and the outcomes of conservative and surgical treatments, as well as the incidence of complications following partial or total excision of a sesamoid, would be a welcome contribution to the foot and ankle surgical literature. References 1. Renander A. Two cases of typical osteochondropathy of the medial sesamoid bone of the first metatarsal. Acta Radiologica 3:521–527, 1924.
2. National Heart, Lung, and Blood Institute. Calculate your body mass index. Available at: http://www.nhlbisupport.com/bmi/. Accessed November 8, 2008. 3. Ogata K, Sugioka Y, Urano Y, Chikama H. Idiopathic osteonecrosis of the first metatarsal sesamoid. Skeletal Radiol 15(2):141–5, 1986. 4. Toussirot E, Jeunet L, Michel F, Kantelip B, Wendling D. Avascular necrosis of the hallucal sesamoids update with reference to two casereports. Joint Bone Spine 70(4):307–309, 2003. 5. Keating S, Fisher D, Keating D. Avascular necrosis of an accessory sesamoid of the foot. A case report. J Am Podiatr Med Assoc 77(11): 612– 615, 1987. 6. Fleischli J, Cheleuitte E. Avascular necrosis of the hallucial sesamoids. J Foot Ankle Surg 34(4):358 –365, 1995. 7. Miller TT. Painful accessory bones of the foot. Semin Musculoskelet Radiol 6(2):153–161, 2002. 8. Jahss MH. The sesamoids of the hallux. Clin Orthop Relat Res 157:88 –97, 1981. 9. Mann RA, Coughlin MJ. Sesamoids and accessory bones of the foot. In Surgery of the Foot and Ankle, pp 467–538, edited by J Ryan, Mosby CV, St Louis, 1993. 10. Karasick D, Schweitzer ME. Disorders of the hallux sesamoid complex: MR features. Skeletal Radiol 27(8):411– 8, 1998. 11. Chamberland PD, Smith JW, Flemming LL. The blood supply to the great toe sesamoids. Foot Ankle 14(8):435– 442, 1993. 12. Ozkoç G, Akpinar S, Ozalay M, Hersekli MA, Pourbagher A, Kayaselçuk F, Tandogan RN. Hallucal sesamoid osteonecrosis: an overlooked cause of forefoot pain. J Am Podiatr Med Assoc 95(3):277– 280, 2005. 13. Waizy H, Jäger M, Abbara-Czardybon M, Schmidt TG, Frank D. Surgical treatment of AVN of the fibular (lateral) sesamoid. Foot Ankle Int 29(2):231–236, 2008. 14. Kanatli U, Ozturk AM, Ercan NH, Ozalay M, Daglar B, Yetkin H. Absence of the medial sesamoid bone associated with metatarsophalangeal pain. Clin Anat 19(7):634 – 639, 2006. 15. Sexena A, Krisdakumtorn T. Return to activity after sesamoidectomy in athletically active individuals. Foot Ankle Int 24(5):415– 419, 2003.
VOLUME 48, NUMBER 2, MARCH/APRIL 2009
207
P edal sesamoid bone disorders are a rare cause of metatarsal pain, the diagnosis of which can be rather difficult to make. Once the diagnosis is made, moreover, the condition can be difficult to treat. Avascular necrosis (AVN) of the metatarsal sesamoids was first described by Renander, in 1924 (1), and the condition remains an infrequent and incompletely defined pathology of the hallux sesamoid bones. This report describes an atypical case of hallucial sesamoid avascular necrosis. Case Report A 62-year-old retired male engineer with a body mass index of 26 (overweight) (2), presented to our outpatient clinic with a 2-year history of pain under the base of his right great toe, which was aggravated by weight bearing, and he related no history of preceding trauma. The patient was a lifelong heavy smoker with suspected but unconfirmed peripheral vascular disease. His significant past med-
Address correspondence to Geraint Williams, MBCHB, ST2 Orthopaedics, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom CH49 5PE. E-mail: [email protected]. 1 ST2 Orthopaedics, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom. 2 FY2 Orthopaedics, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom. 3 Consultant Orthopaedic Surgeon, Wirral University Hospital NHS Trust, Arrowe Park Hospital, Arrowe Park Road, Upton, Merseyside, United Kingdom. Financial Disclosure: None reported. Conflict of Interest: None reported. Copyright © 2009 by the American College of Foot and Ankle Surgeons 1067-2516/09/4802-0017$36.00/0 doi:10.1053/j.jfas.2008.11.004
ical history included depression, diverticular disease, and a previous right leg deep vein thrombosis in the distant past. On presentation, simple observation of the patient’s gait revealed a reluctance to push off or sustain weight through the right great toe. An area of maximal tenderness was identified under the metatarsal head, and this site corresponded to the sesamoid bones of his right foot. Radiographic inspection demonstrated the presence and correct alignment of the sesamoids of the right first metatarsophalangeal joint (MTPJ); and the fibular sesamoid demonstrated an irregular shape and sclerosis that was suggestive of the presence of avascular necrosis (Figure 1). After 6 months of conservative management with custom orthotic devices, the patient related little improvement in regard to his symptoms, and he consented to an injection of 40 mg of triamcinolone acetonide mixed with 10 mL of 1% plain lidocaine. Image intensification was used to guide the needle between the metatarsal head and fibular sesamoid from a plantar approach. This procedure provided 3 days of total symptom relief, followed by a recurrence of symptoms. Steroid injection is not a recognized treatment for sesamoid bone necrosis but is often administered in the early stages of the disease as a relatively conservative measure before sesamoid excision and confirmatory histological diagnosis (3). A technetium (99Tc) bone scan demonstrated focal uptake in the region of his right first MTPJ, during the third phase of the scan (Figure 2). Magnetic resonance image (MRI) scans demonstrated a small, irregular fibular sesamoid with surrounding fat edema (Figure 3). T1-weighted coronal MRI scans demonstrated low signal intensity that was indicative of fibular sesamoid marrow edema (Figure 4). The combination of clinical findings, along with the diagnostic imaging studies and the lack of a history of direct trauma, suggested a diagnosis of AVN of the fibular sesamoid. VOLUME 48, NUMBER 2, MARCH/APRIL 2009
203
FIGURE 1 Anteroposterior radiographic view demonstrating irregular shape and sclerosis of the fibular sesamoid (arrow).
FIGURE 3 Anteroposterior T1-weighted MRI demonstrating a small, irregular fibular sesamoid with surrounding fat edema (arrows).
FIGURE 4 Coronal T1-weighted MRI demonstrating low signal intensity indicative of fibular sesamoid marrow edema (arrow).
FIGURE 2 A technetium (99Tc) bone scan demonstrating focal uptake in the region of his right first MTPJ (arrow).
In response to his unresolved symptoms and the suspected diagnosis of sesamoidal AVN, the decision was made to pursue excision of the fibular sesamoid through a small, curvilin204
THE JOURNAL OF FOOT & ANKLE SURGERY
ear, plantar incision over the first metatarsal head (Figure 5). The plantar nerve was identified and protected throughout the dissection. The fibular sesamoid was accessed through the flexor hallux brevis tendon, which was repaired with a continuous multifilament absorbable suture (Figure 6). The patient was discharged to his home on the same day as the surgery, with advice to bear weight and to ambulate to his tolerance.
FIGURE 6 The fibular sesamoid was accessed via retraction of the flexor hallux brevis tendons.
FIGURE 5 A small curvilinear, plantar approach was used to excise the fibular sesamoid.
Subsequent, histological examination of the excised fibular sesamoid verified bone necrosis (Figure 7), with micrographic (⫻10) evidence of a zone of transition from relatively healthy cortical bone with abundant viable osteoblasts, to necrotic bone devoid of viable osteoblasts and empty lacunae. Histological inspection also revealed the appearance of end-on capillaries traversing necrotic sections of bone, which was indicative of attempted revascularization (Figure 7). The specific histopathological features observed in the specimen related to this case report were consistent with a diagnosis of AVN of the fibular sesamoid bone (4). Twenty months after surgery, our patient’s gait pattern returned to normal and most of his symptoms had resolved. The patient did not display any clinical or radiographic evidence of hallux varus, despite having had his fibular sesamoid removed (Figures 8 and 9). He did, however, begin to develop intermittent discomfort in the region of the tibial sesamoid of the right first MTPJ, and this required occasional use of paracetamol and his orthotic insoles, and continues to maintain periodic follow-up examinations.
FIGURE 7 Microscopic inspection of the excised fibular sesamoid revealed a zone of transition from healthy cortical bone (A) with abundant viable osteoblasts, to necrotic bone (B) with empty lacunae devoid of viable osteoblasts, as well as end-on capillaries traversing necrotic sections of bone (C).
Discussion Osteonecrosis of the hallucial sesamoid bones is a relatively rare disorder, and the prevalence of this condition is unclear (5). The case described in this report was somewhat atypical, in that the condition is classically reported in females presenting in adolescence with a precipitating history of minor forefoot trauma (1, 4 – 6). Under normal conditions the hallucial sesamoids act as a fulcrum to increase mechanical force in the toe off phase of gait, and they are also thought to protect the MTPJ and the long flexor tendon to the hallux, as the tendon of flexor hallucis brevis and the sesamoids serve as shock absorbers plantar to the first metatarsal head (6, 7). As demonstrated by our patient, mechanically induced pain plantar to the first metatarsal on VOLUME 48, NUMBER 2, MARCH/APRIL 2009
205
FIGURE 8 At 20 months following excision of the fibular sesamoid, the weight-bearing clinical appearance of the right foot revealed no evidence of hallux varus.
FIGURE 9 Latest anteroposterior radiographic view demonstrating absence of fibular sesamoid following excision with no radiographic evidence of hallux valgus.
weight bearing is the foremost presenting symptom in patients with avascular necrosis of a hallucial sesamoid and, in this particular respect, our case was rather conventional. Sclerosis, flattening, and demineralization are classical radiographic findings of sesamoid AVN. Fragmentation into 2 or more pieces is also common, and a “bone dust” appearance due to a multitude of fragments can sometimes be seen radiographically (4, 5). Care should be exercised not to mistake ossification, which is complete between 9 and 14 years of age (8), for fragmentation. It should also be noted that a lag time of up to 6 months between the onset of symptoms and distinct radiographic change is not an unusual occurrence (9). Therefore, in the acute situation, other 206
THE JOURNAL OF FOOT & ANKLE SURGERY
imaging techniques should be considered if radiographs are normal and a diagnosis of AVN is suspected. Our patient presented after an approximately 2-year period of slowly worsening symptoms and, as such, it was not surprising that distinct radiographic changes were evident at that time. It has been postulated that bone scanning is most useful for early diagnosis, since increased technetium (99Tc) uptake in areas of revascularization and remodeling supersedes the onset of radiographic changes. However, decreased or no uptake may occur in the early stages of the necrotic process (4, 5). We feel that technetium bone scanning may not be as useful a diagnostic measure as previously suggested, since our case demonstrated equivocal findings using this technique after a prolonged symptomatic period. MRI is probably the single most useful noninvasive investigative modality, when osteonecrosis is being considered, because signal abnormalities become visible during the first few days of the osteonecrotic process and T1weighted sequences rapidly show replacement of fat and hematopoietic tissue with fibrosis (10). The pathophysiology of sesamoid avascular necrosis is unclear. Trauma leading to the disruption of the tenuous blood supply of the hallucial sesamoids has been postulated as a potential cause (1, 4 – 6, 11). The extraosseous blood supply to the sesamoids originates from a branch of the medial plantar artery, and the intraosseous supply is derived mainly from a single vessel that commonly enters the proximal aspect of each bone. Plantar vessels also penetrate the nonarticular surfaces of the sesamoids, and occasionally capsular vessels provide a minor contribution to the distal zone of each sesamoid. Despite this network of blood vessels, the hallucial sesamoids do not demonstrate the rich anastomotic ring of vessels that is required to maintain adequate perfusion after disruption of the primary intraosseous arterial supply (11). Because the onset of symptoms in the case described in this article was insidious, and there was no history of trauma, spontaneous osteonecrosis may have occurred secondary to a microvascular event that interrupted the primary blood supply to the fibular sesamoid. Our patient presented with the unusual finding of radiographic evidence of an abnormal fibular sesamoid, suggesting the diagnosis of AVN at the time of presentation to our practice. Bipartite and abnormally shaped hallucial sesamoids have been show to demonstrate variability in regard to vascular supply, wherein the blood supply enters either the proximal or distal pole of the ossicle (11). For this reason, treatment by means of partial sesamoidectomy, which has been recommended by some authors (12, 13), could result in necrosis of the remaining fragment of bone, and symptom recurrence. Because we were concerned about this potential problem in the patient described in this article, and because the MRI scans did not clearly localize the precise extent of the necrotic process, we felt that the best option for our patient was total excision of the pathological sesamoid.
Published literature regarding the management of sesamoid avascular necrosis suggests that patients follow an initial course of conservative treatment, followed by complete sesamoidectomy if the patient fails to satisfactorily respond to nonsurgical treatment efforts (1, 4 – 6). It should also be noted that, as was the case with the patient described in this article, removal of the entire lateral sesamoid could be followed by the development of increased pain localized to the medial (tibial) sesamoid. The development of pain plantar to the first metatarsal because of the absence of the fibular sesamoid is generally understood to be a relatively common complication of complete sesamoidectomy. This condition has been attributed to alteration of weight-bearing mechanical function around the metatarsal head, and to postsurgical scaring with neuromalike symptoms (14). Occasionally, patients may develop hallux varus following complete excision of the fibular sesamoid (15). The prevalence of these complications, as well as the optimal method of treatment, has not been thoroughly defined; and the use of analgesic medications and custom foot orthoses can be helpful, as was the case with the patient described in this report. Future investigations into the prevalence of hallucial sesamoid AVN, and the outcomes of conservative and surgical treatments, as well as the incidence of complications following partial or total excision of a sesamoid, would be a welcome contribution to the foot and ankle surgical literature. References 1. Renander A. Two cases of typical osteochondropathy of the medial sesamoid bone of the first metatarsal. Acta Radiologica 3:521–527, 1924.
2. National Heart, Lung, and Blood Institute. Calculate your body mass index. Available at: http://www.nhlbisupport.com/bmi/. Accessed November 8, 2008. 3. Ogata K, Sugioka Y, Urano Y, Chikama H. Idiopathic osteonecrosis of the first metatarsal sesamoid. Skeletal Radiol 15(2):141–5, 1986. 4. Toussirot E, Jeunet L, Michel F, Kantelip B, Wendling D. Avascular necrosis of the hallucal sesamoids update with reference to two casereports. Joint Bone Spine 70(4):307–309, 2003. 5. Keating S, Fisher D, Keating D. Avascular necrosis of an accessory sesamoid of the foot. A case report. J Am Podiatr Med Assoc 77(11): 612– 615, 1987. 6. Fleischli J, Cheleuitte E. Avascular necrosis of the hallucial sesamoids. J Foot Ankle Surg 34(4):358 –365, 1995. 7. Miller TT. Painful accessory bones of the foot. Semin Musculoskelet Radiol 6(2):153–161, 2002. 8. Jahss MH. The sesamoids of the hallux. Clin Orthop Relat Res 157:88 –97, 1981. 9. Mann RA, Coughlin MJ. Sesamoids and accessory bones of the foot. In Surgery of the Foot and Ankle, pp 467–538, edited by J Ryan, Mosby CV, St Louis, 1993. 10. Karasick D, Schweitzer ME. Disorders of the hallux sesamoid complex: MR features. Skeletal Radiol 27(8):411– 8, 1998. 11. Chamberland PD, Smith JW, Flemming LL. The blood supply to the great toe sesamoids. Foot Ankle 14(8):435– 442, 1993. 12. Ozkoç G, Akpinar S, Ozalay M, Hersekli MA, Pourbagher A, Kayaselçuk F, Tandogan RN. Hallucal sesamoid osteonecrosis: an overlooked cause of forefoot pain. J Am Podiatr Med Assoc 95(3):277– 280, 2005. 13. Waizy H, Jäger M, Abbara-Czardybon M, Schmidt TG, Frank D. Surgical treatment of AVN of the fibular (lateral) sesamoid. Foot Ankle Int 29(2):231–236, 2008. 14. Kanatli U, Ozturk AM, Ercan NH, Ozalay M, Daglar B, Yetkin H. Absence of the medial sesamoid bone associated with metatarsophalangeal pain. Clin Anat 19(7):634 – 639, 2006. 15. Sexena A, Krisdakumtorn T. Return to activity after sesamoidectomy in athletically active individuals. Foot Ankle Int 24(5):415– 419, 2003.
VOLUME 48, NUMBER 2, MARCH/APRIL 2009
207