Skeletal Radiology
Skeletal Radiol (1992) 21:319-320
Case report 721 J.F.M. Meaney, M.R.C.P.I., D.M.R.D., and J.M. Desmond, D.M.R.D., F.R.C.R. Department of Radiology, Warrington General Hospital, Warrington, UK
Radiological studies
Clinical information A 24-year-old man stubbed his foot while "hill-walking ". The great toe became acutely painful, and he could not bear weight on it. Examination revealed fixed hyperextension of the interphalangeal joint, which was exquisitely tender. Plain radiographs revealed widening of the interphalangeal joint space with the sesamoid projected over the joint space on both AP and lateral views (Fig. 1).
Fig. 1. A An AP radiograph demonstrates widening of the joint space with projection of the sesamoid bone over the joint space. B A lateral radiograph shows hyperextension of the joint and confirms the intraarticular position of the sesamoid
Address reprint requests to: Dr. J.M. Desmond, Department of Radiology, Warrington General Hospital, Lovely Lane, Warrington, UK
9 1992 International Skeletal Society
320
J.F.M. Meaney et al.: Case report 721
Diagnosis: Intraarticular dislocation of a sesamoid in the first toe (type I) The findings confirm the presence of a dislocated sesamoid within the interphalangeal joint. Manual reduction was successfully achieved under local anesthesia, and post-manipulation radiographs confirmed that the sesamoid had been successfully reduced (Fig. 2). The patient regained full use of the joint without sequelae.
Discussion Intraarticular dislocation of a sesamoid is extremely rare, and review of the English literature has revealed few previous cases at this site [1-8]. the mechanism appears to involve a forceful axial load being applied to the end of the digit [3], and all published cases appear to have followed injuries of some severity. Masaki described the presence of a sesamoid at this site in 93% of patients [4]. However, routine radiographic demonstration depends on the size of the sesamoid and the quality of the radiograph. The interphalangeal (SP) sesamoid of the hallux is a type A sesamoid (i.e., one incorporated along with its tendon into the joint capsule; tape B seasamoids are located where tendons are angled around a bony surface and are separated from the underlying bone by a bursa) [8]. The anatomy of the IP joint of the hallux is relatively straightforward and simple [5]: The sesamoid bone is located in the volar plate which is a strong condensation of fascia on the dorsal aspect of the joint capsule. The sesamoid in the volar plate is connected by ligaments to both the proximal and distal phalanges at the articular margins and separated from the tendon of flexor hallicus longus by loose connective tissue. The paired collateral ligaments confer lateral stability. For dislocation of the joint to occur, the vo-
Fig. 2 A, B. AP and lateral radiographs confirm a successful reduction
lar plate must detach from its proximal and/or distal attachments. In type 1 dislocations [5], subluxation or dislocation occurs with the plantar plate displaced into the IP joint space. Type 2 dislocations, the plantar plate, including the sesamoid, is displaced dorsally over the proximal phalangeal head. Radiographically, the two types of dislocation differ in that the sesamoid is located within the joint in type 1 dislocations, resulting in marked widening of the joint space. Dislocation occurs but dorsally over the proximal phalageal head with hyperextension of the IP joint in type 2 dislocations.The case we report is a type 1 dislocation. Although the literature suggests that treatment is rarely successful [9], this patient was treated by closed reduction which should be attempted before resorting to surgery [8], followed by application of an immobilizing splint for 6 weeks. In summary, a case of intraarticular dislocation (due to trauma) of a hallux sesamoid is presented. The two-types of dislocation are described. Treatment was by closed reduction.
References 1. Barnett JC, Crespo A, Daniels VC (1979) Intra-articular accessory sesamoid dislocation of the great toe. J F1 Med Assoc 66:613 2. Eibel P (1954) Dislocation of the interphalangeal joint of the big toe with interposition of a sesamoid bone. J Bone Joint Surg [Am] 36:880 3. Kursonoglu S, Resnick D, Goergen T (1987) Traumatic dislocation with sesamold entrapment in the interphalangeal joint of the great toe. J Trauma 27:959 4. Masaki T (1984) An anatomical study of the interphalangeal sesamoid bone of the hallux (Japanese). J Jpn Orthop Assoc 58:417 5. Miki T, Yamamuro T, Kitoi T (1988) An irreducible dislocation of the great toe. Report of two cases and review of the literature. Clin Orthop 230:200 6. Muller GM (1944) Dislocation of sesamoid of hallux. Lancet I: 789 7. Nelson TL, Uggen W (1981) Irreducible dorsal dislocation of the interphalangeal joint of the great toe. Clin Orthop 157:110 8. Szucs R, Hurwitz J (1989) Traumatic subluxation of the interphalangeal joint of the hallux with interposition of the sesamoid bone. Am J Roentgenol 152:652 9. Yasuda T, Fujio K, Kiyoshi T (1990) Irreducible dorsal dislocation of the interphalangeal joint of the great toe: report of two cases. Foot Ankle 10:331
Skeletal Radiol (1992) 21:319-320
Case report 721 J.F.M. Meaney, M.R.C.P.I., D.M.R.D., and J.M. Desmond, D.M.R.D., F.R.C.R. Department of Radiology, Warrington General Hospital, Warrington, UK
Radiological studies
Clinical information A 24-year-old man stubbed his foot while "hill-walking ". The great toe became acutely painful, and he could not bear weight on it. Examination revealed fixed hyperextension of the interphalangeal joint, which was exquisitely tender. Plain radiographs revealed widening of the interphalangeal joint space with the sesamoid projected over the joint space on both AP and lateral views (Fig. 1).
Fig. 1. A An AP radiograph demonstrates widening of the joint space with projection of the sesamoid bone over the joint space. B A lateral radiograph shows hyperextension of the joint and confirms the intraarticular position of the sesamoid
Address reprint requests to: Dr. J.M. Desmond, Department of Radiology, Warrington General Hospital, Lovely Lane, Warrington, UK
9 1992 International Skeletal Society
320
J.F.M. Meaney et al.: Case report 721
Diagnosis: Intraarticular dislocation of a sesamoid in the first toe (type I) The findings confirm the presence of a dislocated sesamoid within the interphalangeal joint. Manual reduction was successfully achieved under local anesthesia, and post-manipulation radiographs confirmed that the sesamoid had been successfully reduced (Fig. 2). The patient regained full use of the joint without sequelae.
Discussion Intraarticular dislocation of a sesamoid is extremely rare, and review of the English literature has revealed few previous cases at this site [1-8]. the mechanism appears to involve a forceful axial load being applied to the end of the digit [3], and all published cases appear to have followed injuries of some severity. Masaki described the presence of a sesamoid at this site in 93% of patients [4]. However, routine radiographic demonstration depends on the size of the sesamoid and the quality of the radiograph. The interphalangeal (SP) sesamoid of the hallux is a type A sesamoid (i.e., one incorporated along with its tendon into the joint capsule; tape B seasamoids are located where tendons are angled around a bony surface and are separated from the underlying bone by a bursa) [8]. The anatomy of the IP joint of the hallux is relatively straightforward and simple [5]: The sesamoid bone is located in the volar plate which is a strong condensation of fascia on the dorsal aspect of the joint capsule. The sesamoid in the volar plate is connected by ligaments to both the proximal and distal phalanges at the articular margins and separated from the tendon of flexor hallicus longus by loose connective tissue. The paired collateral ligaments confer lateral stability. For dislocation of the joint to occur, the vo-
Fig. 2 A, B. AP and lateral radiographs confirm a successful reduction
lar plate must detach from its proximal and/or distal attachments. In type 1 dislocations [5], subluxation or dislocation occurs with the plantar plate displaced into the IP joint space. Type 2 dislocations, the plantar plate, including the sesamoid, is displaced dorsally over the proximal phalangeal head. Radiographically, the two types of dislocation differ in that the sesamoid is located within the joint in type 1 dislocations, resulting in marked widening of the joint space. Dislocation occurs but dorsally over the proximal phalageal head with hyperextension of the IP joint in type 2 dislocations.The case we report is a type 1 dislocation. Although the literature suggests that treatment is rarely successful [9], this patient was treated by closed reduction which should be attempted before resorting to surgery [8], followed by application of an immobilizing splint for 6 weeks. In summary, a case of intraarticular dislocation (due to trauma) of a hallux sesamoid is presented. The two-types of dislocation are described. Treatment was by closed reduction.
References 1. Barnett JC, Crespo A, Daniels VC (1979) Intra-articular accessory sesamoid dislocation of the great toe. J F1 Med Assoc 66:613 2. Eibel P (1954) Dislocation of the interphalangeal joint of the big toe with interposition of a sesamoid bone. J Bone Joint Surg [Am] 36:880 3. Kursonoglu S, Resnick D, Goergen T (1987) Traumatic dislocation with sesamold entrapment in the interphalangeal joint of the great toe. J Trauma 27:959 4. Masaki T (1984) An anatomical study of the interphalangeal sesamoid bone of the hallux (Japanese). J Jpn Orthop Assoc 58:417 5. Miki T, Yamamuro T, Kitoi T (1988) An irreducible dislocation of the great toe. Report of two cases and review of the literature. Clin Orthop 230:200 6. Muller GM (1944) Dislocation of sesamoid of hallux. Lancet I: 789 7. Nelson TL, Uggen W (1981) Irreducible dorsal dislocation of the interphalangeal joint of the great toe. Clin Orthop 157:110 8. Szucs R, Hurwitz J (1989) Traumatic subluxation of the interphalangeal joint of the hallux with interposition of the sesamoid bone. Am J Roentgenol 152:652 9. Yasuda T, Fujio K, Kiyoshi T (1990) Irreducible dorsal dislocation of the interphalangeal joint of the great toe: report of two cases. Foot Ankle 10:331
