Os hypotriquetrum. Radiographic Examination  The sesamoids and collateral ligaments provide medial and lateral stability to the metatarsophalangeal joint. B4 and B5, Custom inserts with sesamoid region molded to diminish pressure. Table 10-1 Jahss46 noted that bipartism was 10 times more common in the medial sesamoid. 1928 Jan; 62 (Pt 2):182.6–18183. Surface Anatomy and Surface Markings You may also needSesamoids and Accessory Bones of the FootBiomechanics of the Foot and AnkleBiomechanics of the Foot and AnkleCongenital and Acquired Neurologic DisordersCongenital and Acquired Neurologic DisordersImaging of the Foot and AnkleSoft Tissue and Bone TumorsImaging of the Foot and Ankle A, The most common pattern of arterial circulation to the sesamoids (52% of cases) involves a direct branch from both the medial plantar artery and the plantar arch. They may be totally or partially contained within the tendinous structure. This variability in ossification might explain the radiographic absence or presence of various sesamoids, as well as the incidence of bipartism of sesamoids. 10-3). D, From Jahss MS, editor: Disorders of the foot and ankle: medical and surgical management, ed 2, Philadelphia, 1991, WB Saunders.) Congenital variations of the sesamoids can lead to localized discomfort if the plantar surface of the sesamoid is irregular. Top and side views. E, Gross pathology of a specimen. Evaluation and Treatment  Anatomy and Incidence  Although ossification of the hallucial sesamoids is variable, Kewenter reported that ossification usually occurs between the sixth and seventh years. Avascular necrosis secondary to fracture was noted in 9 cases, 16 cases were diagnosed as stress fractures, and 12 cases were related to direct trauma. D and E, From Jahss MS, editor: Disorders of the foot and ankle: medical and surgical management, ed 2, Philadelphia, 1991, WB Saunders.). Kewenter54,214 examined a series of sesamoids in cadavers and found that congenitally divided sesamoids fracture with much less force than normal sesamoids when experimental trauma was introduced. 10-5), which is an extension of the flexor hallucis brevis tendon. 10-12A, B, and C). Sesamoid bones were found in the IP joint of the thumb at 67% (212 of 318), while the index, middle, ring, little fingers had sesamoid bones in the proximal interphlangeal (PIP) joint at 0% (0 of 172), 0.4% (1 of 244), 0.5% (1 of 183), and 1% (2 of 179), respectively. Anteroposterior (AP) (A) and lateral (B) radiographs of patient with absence of medial and lateral sesamoids. The dictionary definition, however, states that sesame is an East Indian herb with oily edible seeds. Pretterklieber and Wanivenhaus,77 in dissections of 29 cadavers, reported three different types of arterial circulation. Clinical Significance  Kewenter54,214 noted that the medial sesamoid is located slightly more distal than the lateral sesamoid and is slightly larger. C, Moderate hallux valgus deformity associated with moderate sesamoid subluxation. (From Toussirot E, Jeunet L, Michel F, et al: Avascular necrosis of the hallucal sesamoids update with reference to two case-reports, Joint Bone Spine 70:307–309, 2003.) C, Magnetic resonance imaging of lateral sesamoid fragmentation. C, An axial radiograph demonstrates a longitudinal bipartite medial sesamoid. 10-24). First MTP sesamoid abnormalities are uncommon, but degeneration or isolated injury can cause pain and significant dysfunction. Rosenfield and Trepman85 have described the use of a rocker-soled walking shoe with a full-length steel shank. The inferior surface of the sesamoids is covered by a thin layer of the flexor hallucis brevis tendon, whereas the superior surface is articular in nature. Clinical Significance  Two patients had a persistent nonunion. They speculated that the medial sesamoid has a higher frequency of bipartism than the lateral sesamoid because it is more often traumatized, a result of its greater weight-bearing capacity. They noted that a dorsolateral approach may be more difficult for fibular sesamoidectomy and that the two nerve problems both occurred with a dorsolateral approach. Figure 10-22 Absence of fibular sesamoid. Riley and Selner82 used a circlage wire and bone grafting in one case, and Blundell et al9 used a percutaneous screw in nine cases and reported successful union. Meanwhile, differences among each HSB type may be a major factor affecting the occurrence and development of HV. Through an inferior extraarticular approach, they curetted and bone grafted the diastasis “nonunion site.” No internal fixation was used. Injury to the Sesamoids. 10-13D). This complex joint is the source of many knee complaints especially in active individuals. Congenital absence of both sesamoids. When a person rises onto the toes, the sesamoids (especially the medial sesamoid) act as the main weight-bearing focus for the medial forefoot (Fig. D, A medial oblique radiograph shows more clearly the tibial sesamoid. Arthritis is more likely to be a problem in people who have high arches in their feet. Sesamoid bones are also found occasionally at the metacarpophalangeal joints of the middle and ring fingers, at the interphalangeal joint of the thumb and at the distal interphalangeal joint of the index finger. This variability in ossification might explain the radiographic absence or presence of various sesamoids, as well as the incidence of bipartism of sesamoids.91. The sesamoid arteries branch off from the digital plantar arteries of the hallux, which, in turn, are derived from the medial plantar artery and the plantar arch (type A), the plantar arch (type B), or the medial plantar artery (type C). Kewenter54,214 examined 800 feet and found a 31% incidence of bipartite tibial sesamoids (Fig. The fibular sesamoid is best demonstrated in a lateral oblique radiograph (Fig. Figure 10-19 Anteroposterior radiograph (A1), computed tomography scan (A2), and lateral radiograph (A3) demonstrating nondisplaced fracture of tibial sesamoid. ARTHRITIS  Progressive insidious deviation of the hallux can develop with sesamoid disruption caused by trauma or fracture. Anatomy The other patients returned to normal activities in 12 weeks. 10-19). B2, Plastazote insert with proximal Hapad and area beneath sesamoid relieved. Although absence of a sesamoid can be asymptomatic, removal of a sesamoid for painful plantar keratosis can cause postoperative pain beneath the remaining sesamoid. D, An extra-depth shoe might be necessary to accommodate the specific insert used to relieve sesamoid pain. J Anat. It has not been determined whether continued trauma with ambulation prevents the union of divided sesamoids or whether some of these partite sesamoids are actually nonunions of fractures. 44 The anatomic location of several of the sesamoids is constant, but the frequency of occurrence of other sesamoids is quite variable. 10-23A, B, and C). B1, Insole with Hapad placed just proximal to the sesamoids, relieving pressure. Sesamoid bones are common in humans, and vary in number. Rodeo et al83 reported on four cases of injuries to the hallux with progressive diastasis of bipartite sesamoids. Clinical Significance  B, AP radiograph of symptomatic bipartite medial sesamoid. Tags: Manns Surgery of the Foot and Ankle Expert Consult Learn more. D, From Jahss MS, editor: Disorders of the foot and ankle: medical and surgical management, ed 2, Philadelphia, 1991, WB Saunders. A, Anteroposterior radiograph of absent fibular sesamoid with bipartite medial sesamoid. Bipartite Sesamoids and Fractures An anteroposterior (AP) radiograph demonstrates the normal position of the sesamoids. 10-15) and a symptomatic bipartite sesamoid.30,104 With a divisionary line between two segments of a sesamoid, a careful physical examination and history must be correlated with radiographic findings to differentiate between a partite sesamoid and a superimposed fracture.30 With a sesamoid fracture, pain is localized to the region of the specific sesamoid. Sobel et al97 and Rath et al,78 in their evaluation of sesamoid vascularity, mapped the vascular supply as well of both the medial and lateral sesamoids. On the dorsoplantar view, the metatarsal head overlies both the medial and lateral sesamoid and often obscures detail; on the lateral projection, the medial and lateral sesamoids overlap each other. (Courtesy R. Anderson, MD, Charlotte, N.C.) A crista, or intersesamoid ridge (Fig. Although ossification of the hallucial sesamoids is variable, Kewenter reported that ossification usually occurs between the sixth and seventh years. Brodsky et al13 retrospectively reviewed a series of 37 patients with fractured sesamoids. The patients were placed in a below-knee cast and kept non–weight bearing for 4 weeks. Sesamoids occur in the substance of their corresponding tendon. (C, From Williams TH, Pasapula C, Robinson AH: Complete sesamoid agenesis: a rare cause of first ray metatarsalgia, Foot Ankle Int 30:465–467, 2009. On the medial aspect of the MTP joint, the abductor hallucis tendon (Fig. Vascular anastomoses occur between the proximal supply and that derived from the plantar surface to the body of the sesamoid (Fig. The distal portion of the sesamoid has the most tenuous vascular supply, and this can lead to delayed or unsuccessful healing after injury. Conservative Treatment  cartilaginous dorsal surface articulates with the grooved undersurface of the first metatarsal head; Attachments. With compression of either the medial or lateral digital nerve by either the tibial or fibular sesamoid, a Tinel sign can be elicited along the border of the sesamoid. Taping of the toe to reduce dorsiflexion can also relieve symptoms. 10-11C), where it can be seen between the first and second metatarsal heads. Treatment  NSAIDs, reduced weightbearing, activity modification, orthoses. They also reported that the incidence of division decreased with time, thus implying that osseous union occurs with time in the divided sesamoid. Anatomy and Incidence  OS TALONAVICULARE DORSALE, OS SUPRATALARE  Congenital variations of the sesamoids can lead to localized discomfort if the plantar surface of the sesamoid is irregular. Clinical Significance  Rosenfield and Trepman85 have described the use of a rocker-soled walking shoe with a full-length steel shank. They demonstrated both proximal and distal vessels branching off the two major arteries. D, Severe hallux valgus associated with severe subluxation of the sesamoids. D, Radiograph of the medial sesamoid, demonstrating a large plantar exostosis. Close inspection of the plantar articular surface of the first metatarsal frequently reveals substantial cartilage erosion and degenerative arthritis in this area (Fig. C, Lateral radiograph demonstrating alignment of proximal and distal fragments. D, Axial view after excision of medial sesamoid. The sesamoids not only absorb weight-bearing forces on the medial aspect of the forefoot but also increase the mechanical advantage of the intrinsic musculature in plantar-flexing the proximal phalanx. D, Radiograph of the medial sesamoid, demonstrating a large plantar exostosis. 10-25A and B). The sesamoids function to alter the direction of muscle pull, diminish friction, and modify pressure. The fibular sesamoid is best demonstrated in a lateral oblique radiograph (, The incidence of partite sesamoids as well as their cause has been the subject of substantial discussion in the literature (Table 10-1). F and G, Immediately after surgery. Examination of the sensory nerves of the first ray is important in diagnosing a compressed digital nerve, Routine dorsoplantar and lateral radiographs (Fig. Vascular anastomoses occur between the proximal supply and that derived from the plantar surface to the body of the sesamoid (Fig. The proximal arterial supply, through the flexor hallucis brevis, supplies one third to two thirds of the proximal sesamoid. The major vascular supply enters the sesamoids from the proximal and plantar aspect, with a minor arterial supply entering through the distal pole of the sesamoids (Fig. B3, Custom insert with proximal Hapad. ACCESSORY BONES OF THE FOOT AND THE UNCOMMON SESAMOIDS  Custom and prefabricated orthotics and scaphoid and metatarsal pads can relieve pressure in the sesamoid region, diminishing symptoms. In the less common types, circulation was derived mainly from either the plantar arch or only from the medial plantar artery (Fig. 10-24). Three other patients had excessive motion at the diastasis site and were not considered candidates for bone grafting. Like other joints in the body, this joint can also develop arthritis. Routine dorsoplantar and lateral radiographs (Fig. D and E, From Jahss MS, editor: Disorders of the foot and ankle: medical and surgical management, ed 2, Philadelphia, 1991, WB Saunders.) If conservative methods fail, surgical removal of the involved sesamoid may be necessary (see Fig. OS CALCANEUS SECUNDARIUS  Hobart40 recommended non–weight bearing and casting until the sesamoid fracture had healed, which usually occurred in 6 to 8 weeks (Fig. Anatomy and Incidence  Figure 10-13 Many variations can occur in ossification of sesamoids of the metatarsophalangeal joint of the hallux. D and E, Fifteen-year follow-up. Alignment of the first metatarsophalangeal joint is well maintained. (Courtesy R. Anderson, MD, Charlotte, N.C.). Complications included one varus deformity, one valgus deformity, and two cases of neuroma formation associated with fibular sesamoidectomy. How to use sesamoid in a sentence. 10-14). Ossification Figure 10-20 A, Intractable plantar keratotic lesion directly beneath the tibial sesamoid. The most common sesamoid bones are those of the foot, including the hallucal sesamoids, lesser metatarsal sesamoids, interphalangeal joint sesamoid of the great toe, os peroneum, sesamoid within the anterior tibial tendon, and sesamoid within the post… Decision Making in the Excision of a Sesamoid (Video Clips 64 and 65)  The absence of a tibial sesamoid can produce a clawing of the hallux or development of a progressive postoperative hallux valgus deformity (see Fig. Alignment of the first metatarsophalangeal joint is well maintained. Clinical Significance  (C, From Williams TH, Pasapula C, Robinson AH: Complete sesamoid agenesis: a rare cause of first ray metatarsalgia, Foot Ankle Int 30:465–467, 2009. Figure 10-8 A, Anteroposterior (AP) radiograph immediately after hyperextension injury of the first metatarsophalangeal joint. Treatment  (Modified from Sobel M, Hashimoto J, Amoczky SP, Bohne WH: The microvasculature of the sesamoid complex: its clinical significance, Foot Ankle 13:359–363, 1992.). Figure 10-15 A, An anteroposterior radiograph demonstrates a painful bipartite sesamoid. C, Magnetic resonance image demonstrating absent lateral sesamoid. Some sesamoids totally ossify, some remain entirely cartilaginous, and some partially ossify with a fibrocartilaginous interface between the ossified fragments. Figure 10-8 A, Anteroposterior (AP) radiograph immediately after hyperextension injury of the first metatarsophalangeal joint. Bone scan helps distinguish a bipartite sesamoid from a fracture ; use caution with interpretation as 25%-30% of asymptomatic patients can have increased uptake increased uptake compared to uninjured side helps diagnosis; Treatment: Nonoperative . In severe cases of hallux valgus, with substantial subluxation of the sesamoid complex in relation to the first metatarsal head, the intersesamoid ridge atrophies and at times is obliterated (Fig. * Substantial trauma with MTP joint dislocation and simultaneous fractures of both sesamoids have been reported23,103; in general, the most frequently reported mechanism of injury is a fall onto the forefoot, sudden loading of the forefoot, or a crush injury. CONGENITAL ABSENCE OF THE SESAMOIDS  Progressive insidious deviation of the hallux can develop with sesamoid disruption caused by trauma or fracture. Two patients had a persistent nonunion. Symptoms are typically exacerbated with ambulation and reduced with rest. MRIs may demonstrate increased vascularity, bone edema, or acute changes, indicating a disruption of a partite sesamoid49 (see Fig. This focuses strain and pressure on the sesamoids. The patients were treated with a distal resection of a smaller fragment and repair of the sesamoid mechanism. A fractured medial sesamoid (arrow) is demonstrated. Complete or partial rupture of the plantar plate attachement may lead to a turf toe deformity with retraction of the sesamoids, restricted motion, and degenerative arthritis of the first metatarsophalangeal joint. OS TRIGONUM  Both these intrinsic muscles also insert into their respective sesamoids. 10-7) inserts into the plantar-medial base of the proximal phalanx as well as the medial sesamoid and functions to stabilize the sesamoid mechanism medially. Anatomy and Incidence  Splanchnology Dobas and Silvers reported that 80% of bipartite sesamoids involve the tibial sesamoid. It can be difficult to distinguish between a fractured sesamoid (see Fig. B, Lateral radiograph of the sesamoids. C, Computed tomography of first ray. Richardson. Kuo et al57 reported a case of nonunion of the fibular sesamoid in association with chronic gout that required surgical excision. D, With dorsiflexion of the hallux, the alignment of the fragments changes, demonstrating motion consistent with a fracture of a partite sesamoid. B, An anteroposterior radiograph demonstrates a bipartite medial sesamoid. They speculated that the medial sesamoid has a higher frequency of bipartism than the lateral sesamoid because it is more often traumatized, a result of its greater weight-bearing capacity. Figure 10-4 Avascular necrosis of the lateral sesamoid. Delay in diagnosis of a sesamoid fracture is therefore common because of the difficulty of confirming the fracture by radiography.102,110. The most common type (type A, 52%), was characterized by arterial circulation derived from the medial plantar artery and the plantar arch. Patellofemoral stress syndrome (PFSS) is a general name for poorly localized anterior knee pain arising from the knee extensor mechanism, without another concrete … Patient remains completely asymptomatic. On the medial aspect of the MTP joint, the abductor hallucis tendon (Fig. C, Lateral radiograph demonstrating alignment of proximal and distal fragments. A cross section of the first metatarsal head demonstrates the sesamoid and the intersesamoidal ridge. 10-23A, B, and C). (Courtesy Hansen Orthotics, Sun Valley, Idaho.). Jeng et al48 and others60,108 have reported cases of an absent fibular sesamoid (Fig. SUBLUXATION AND DISLOCATION OF THE SESAMOIDS  10-11A and 10-11B) can provide limited information in the evaluation of a painful sesamoid. When there is only one blood vessel supplying a sesamoid, a fracture may be at greater risk for avascular necrosis or nonunion. 10-3). An anteroposterior (AP) radiograph demonstrates the normal position of the sesamoids. Figure 10-11 A, Dorsoplantar radiograph demonstrating the metatarsophalangeal sesamoids. This can predispose a bipartite sesamoid to fracture or disruption of the synchondrosis with minimal injury (see Fig. 10-4).10. 10-6) on both the medial and lateral aspects of the MTP joint. There are also two sesamoids in the thumb, within the adductor pollicis and abductor pollicis brevis tendons, and one in each forefinger and one in each wrist. Computed tomography (CT) examination can define osseous changes, such as acute fracture or fragmentation, and magnetic resonance imaging (MRI) examination may demonstrate bone edema, avascular regions, fragmentation or degeneration of a sesamoid early before radiographic changes are demonstrated on plain radiographs (see Fig. B, AP radiograph of both feet 1 year later, demonstrating retraction of the sesamoid complex after disruption of the plantar plate.