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Sesamoid displacement: a rare cause of `clicking thumb'
PERGAMON
Injury, Int. J. Care Injured 30 (1999) 141±143
Case Report
Sesamoid displacement: a rare cause of `clicking thumb' N.V. Deshmukh *, A.N. Saikia, E.R. Norton, S.V. Sonanis Department of Orthopaedics, Airedale General Hospital, Steeton, West Yorkshire, UK Accepted 28 September 1998
1. Case report A 43 year old male supermarket manager presented with pain, restricted movement and clicking of his ®rst metacarpophalangeal (MCP) joint. He had been assaulted one year earlier sustaining an injury to his right thumb. His injury had not been investigated or formally treated. Sudden pain and clicking occurred frequently and were almost unbearable causing him considerable diculty in writing and working. On examination there was slight thickening of the MCP joint with limitation of ¯exion as well as radial and ulnar deviation. Passive straightening of the joint from the ¯exed position produced a fairly constant and extremely painful click. There was generalised tenderness and it was not possible to locate the source of click. There was no triggering of the thumb. Radiographs revealed ¯attening of the ®rst metacarpal head (Figs 1 and 2). It was presumed that he had a ®brosed joint capsule which had led to an overall restriction of joint motion. CT scans and reconstruction views revealed proximal displacement of the radial sesamoid (Figs 3±5). The ulnar sesamoid was in its normal position. By a midlateral longitudinal incision the displaced sesamoid was explored. There was a loose strip of articular cartilage on the ®rst metacarpal head held in place by a dorsal attachment. It was clear that the displaced sesamoid bone undermined this loose articular cartilage and lifted it against the base of the proximal phalanx causing extreme pain and
clicking. The articular surface of the sesamoid bone was degenerate and the sesamoid, together with the loose strip, was excised. The acute symptoms completely settled. The MCP joint remains relatively sti but painless.
* Corresponding author. Department of Orthopaedics, Royal Shrewsbury Hospital, Shrewsbury, Shropshire SY3 8XQ, UK. Tel.: +44-1743-261-000; fax: +44-1743-261-006. 0020-1383/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
Fig. 1. Radiograph of ®rst metacarpophalangeal joint.
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N.V. Deshmukh et al. / Injury, Int. J. Care Injured 30 (1999) 141±143
Fig. 2. Radiograph of ®rst metacarpophalangeal joint.
2. Discussion Although dislocations of the metacarpophalangeal joint of the thumb are common [1], displacement with clicking of the sesamoid in the joint is rare. Intraarticular displacement of the sesamoid without dislocation of the thumb MCP joint is possible with hyperextension injuries [2] and is well described but we could not ®nd any references regarding clicking due to sesamoid displacement. The thenar sesamoids are present in 100% of hands [1]. Both sesamoids are ®rmly encased in the substance of the volar plate of the ®rst metacarpophalangeal joint. The volar plate has a thin, redundant proximal membranous portion and a tough, ®brous, distal portion in which the sesamoids are deeply seated. The insertion of ¯exor pollicis brevis is intimately associated with the radial sesamoid and volar plate. The ulnar sesamoid has a similar association with adductor pollicis tendon [3, 4]. The volar plate has to be avulsed from its proximal phalanx attach-
Fig. 3. CT and reconstruction views showing proximal radial sesamoid displacement.
ment to bring the sesamoid to lie in the joint space [3]. Our patient had a wrenching/twisting injury to his thumb with possible hyperextension injury of the MCP joint with distal volar plate avulsion as con®rmed intraoperatively. There was probably no dislocation of the joint. Reconstruction views revealed that the radial sesamoid was displaced proximally indicating a distal rupture of the volar plate. Posttraumatic arthritis of the sesamoid has been reported previously after hyperextension injury of thumb [5]. Sesamoid excision was carried out in our patient as there was signi®cant proximal sesamoid displacement due to stripping of the sesamoid from the distal volar plate and severe associated articular cartilage damage.
References [1] Rockwood CA, Green DP, Fractures in adults, vol. 1. 4th ed.; Upper extremity. 1996. p. 718±9.
N.V. Deshmukh et al. / Injury, Int. J. Care Injured 30 (1999) 141±143
143
Fig. 4. CT and reconstruction views showing proximal radial sesamoid displacement.
Fig. 5. CT and reconstruction views showing proximal radial sesamoid displacement.
[2] Ishizuki M, Nakagawa T, Ito S. Hyperextension injuries of the metacarpophalangeal joint of the thumb. J Hand Surg 1994;19B:361±7. [3] Desai SS, Morgan W. Locked thumb metacarpophalangeal joint caused by sesamoid entrapment. J Hand Surg 1991;16A:1052±5.
[4] Gibeault JD, Saba P, Hoenecke H, Graham A. The sesamoids of the metacarpophalangeal joint of the thumb: an anatomical and clinical study. J Hand Surg 1989;14B:244±7. [5] Trumble TE, Watson HK. Posttraumatic sesamoid arthritis of the metacarpophalangeal joint of the thumb. J Hand Surg 1985;10A:94±100.
Injury, Int. J. Care Injured 30 (1999) 141±143
Case Report
Sesamoid displacement: a rare cause of `clicking thumb' N.V. Deshmukh *, A.N. Saikia, E.R. Norton, S.V. Sonanis Department of Orthopaedics, Airedale General Hospital, Steeton, West Yorkshire, UK Accepted 28 September 1998
1. Case report A 43 year old male supermarket manager presented with pain, restricted movement and clicking of his ®rst metacarpophalangeal (MCP) joint. He had been assaulted one year earlier sustaining an injury to his right thumb. His injury had not been investigated or formally treated. Sudden pain and clicking occurred frequently and were almost unbearable causing him considerable diculty in writing and working. On examination there was slight thickening of the MCP joint with limitation of ¯exion as well as radial and ulnar deviation. Passive straightening of the joint from the ¯exed position produced a fairly constant and extremely painful click. There was generalised tenderness and it was not possible to locate the source of click. There was no triggering of the thumb. Radiographs revealed ¯attening of the ®rst metacarpal head (Figs 1 and 2). It was presumed that he had a ®brosed joint capsule which had led to an overall restriction of joint motion. CT scans and reconstruction views revealed proximal displacement of the radial sesamoid (Figs 3±5). The ulnar sesamoid was in its normal position. By a midlateral longitudinal incision the displaced sesamoid was explored. There was a loose strip of articular cartilage on the ®rst metacarpal head held in place by a dorsal attachment. It was clear that the displaced sesamoid bone undermined this loose articular cartilage and lifted it against the base of the proximal phalanx causing extreme pain and
clicking. The articular surface of the sesamoid bone was degenerate and the sesamoid, together with the loose strip, was excised. The acute symptoms completely settled. The MCP joint remains relatively sti but painless.
* Corresponding author. Department of Orthopaedics, Royal Shrewsbury Hospital, Shrewsbury, Shropshire SY3 8XQ, UK. Tel.: +44-1743-261-000; fax: +44-1743-261-006. 0020-1383/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
Fig. 1. Radiograph of ®rst metacarpophalangeal joint.
142
N.V. Deshmukh et al. / Injury, Int. J. Care Injured 30 (1999) 141±143
Fig. 2. Radiograph of ®rst metacarpophalangeal joint.
2. Discussion Although dislocations of the metacarpophalangeal joint of the thumb are common [1], displacement with clicking of the sesamoid in the joint is rare. Intraarticular displacement of the sesamoid without dislocation of the thumb MCP joint is possible with hyperextension injuries [2] and is well described but we could not ®nd any references regarding clicking due to sesamoid displacement. The thenar sesamoids are present in 100% of hands [1]. Both sesamoids are ®rmly encased in the substance of the volar plate of the ®rst metacarpophalangeal joint. The volar plate has a thin, redundant proximal membranous portion and a tough, ®brous, distal portion in which the sesamoids are deeply seated. The insertion of ¯exor pollicis brevis is intimately associated with the radial sesamoid and volar plate. The ulnar sesamoid has a similar association with adductor pollicis tendon [3, 4]. The volar plate has to be avulsed from its proximal phalanx attach-
Fig. 3. CT and reconstruction views showing proximal radial sesamoid displacement.
ment to bring the sesamoid to lie in the joint space [3]. Our patient had a wrenching/twisting injury to his thumb with possible hyperextension injury of the MCP joint with distal volar plate avulsion as con®rmed intraoperatively. There was probably no dislocation of the joint. Reconstruction views revealed that the radial sesamoid was displaced proximally indicating a distal rupture of the volar plate. Posttraumatic arthritis of the sesamoid has been reported previously after hyperextension injury of thumb [5]. Sesamoid excision was carried out in our patient as there was signi®cant proximal sesamoid displacement due to stripping of the sesamoid from the distal volar plate and severe associated articular cartilage damage.
References [1] Rockwood CA, Green DP, Fractures in adults, vol. 1. 4th ed.; Upper extremity. 1996. p. 718±9.
N.V. Deshmukh et al. / Injury, Int. J. Care Injured 30 (1999) 141±143
143
Fig. 4. CT and reconstruction views showing proximal radial sesamoid displacement.
Fig. 5. CT and reconstruction views showing proximal radial sesamoid displacement.
[2] Ishizuki M, Nakagawa T, Ito S. Hyperextension injuries of the metacarpophalangeal joint of the thumb. J Hand Surg 1994;19B:361±7. [3] Desai SS, Morgan W. Locked thumb metacarpophalangeal joint caused by sesamoid entrapment. J Hand Surg 1991;16A:1052±5.
[4] Gibeault JD, Saba P, Hoenecke H, Graham A. The sesamoids of the metacarpophalangeal joint of the thumb: an anatomical and clinical study. J Hand Surg 1989;14B:244±7. [5] Trumble TE, Watson HK. Posttraumatic sesamoid arthritis of the metacarpophalangeal joint of the thumb. J Hand Surg 1985;10A:94±100.