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Complete avulsion of the extensor apparatus of the little finger
COMPLETE
AVULSION OF THE EXTENSOR THE LITTLE FINGER
APPARATUS
OF
K. WATANABE, T. U R A S A K I and J. N I S H I K I M I
From the Department of Orthopaedic Surgery, Gifu Prefectural Tajimi Hospital, TajimL Japan We report a case of simultaneous closed avulsions of the terminal extensor insertion and the central slip of the little finger which required operative treatment.
Journal of Hand Surgery (British and European Volume, 1997) 22B: 2:281-282 Closed avulsions of the terminal extensor tendon insertion or the central slip of a finger are common injuries, resulting in mallet deformity and boutonni6re deformity, respectively. Each injury usually occurs in isolation. We present a case of simultaneous closed avulsions of both tendon attachments. To our knowledge there has been no previous report of this type of injury in the literature. CASE REPORT
A 57-year-old man caught his gloved hand in a drill which forced the interphalangeal (IP) and metacarpophalangeal (MP) joints of his fifth finger into excessive flexion. Active flexion of the IP joints was possible, although restricted by severe pain. Active extension was absent (Fig 1). X-rays showed significantly displaced avulsion fractures from the dorsum of the bases of both the distal and middle phalanges, i.e. the insertions of the terminal tendon and the central slip (Fig 2). At exploration 2 days after injury, the extensor apparatus was found to be avulsed from the distal and middle phalanges with a distal laceration of the ulnar lateral band. The avulsed fragments were reduced and fixed with the tension band wire technique (Jupiter and Sheppard, 1987), and the ulnar lateral band was sutured to the radial lateral band. Kirschner wires (1.1 mm) were used to maintain the IP joints in extension for 4 weeks, and the MP and wrist joints were splinted in extension for 3 weeks after the operation. Protected motion was begun after removal of the wires. Fifteen months after the injury, X-rays showed bony union
Fig 2
X-ray showing avulsion fractures from the dorsum of the bases of the distal and middle phalanges.
(Fig 3). The range of flexion of the little finger was 20 to 35° at the distal IP joint, 5 to 70 ° at the proximal IP joint, and minus 5 to 100° at the MP joint (Fig 4). The patient was pain-free in normal everyday activities and satisfied with the functional result. DISCUSSION
Fig 1
Avulsion of the extensor tendon at the insertion of the phalanx is usually caused by sudden forceful flexion of the extended finger. In this case, the mechanism was forceful and excessive flexion of both the IP joints. Sarrafian et al (1970) have described that the peak strain on the terminal tendon is during the initial phase of flexion, and that the peak strain on the central slip occurs just before full flexion. These experimental results suggest that avulsion of the terminal tendon occurred initially, followed by avulsion of the central slip. Since there was significant displacement of both small fragments operative treatment was indicated. Tension band wiring, although not effective for very small
The little finger after the hyperflexion injury. 281
282
T H E J O U R N A L O F H A N D S U R G E R Y VOL. 22B No. 2 A P R I L 1997
Fig4
Fig 3
X-ray showing bony union of both the avulsed fragments 15 months after the operation.
f r a g m e n t s because o f p o o r m a i n t e n a n c e o f tensile forces (Bischoff et al, 1994), was utilised. A l t h o u g h the distal f r a g m e n t was very small, b o n y u n i o n was achieved. References Bischoff R, Buechler U, De Roche R, Jupiter J (1994). Clinical results of tension band fixation of avulsion fractures of the hand. Journal of H a n d Surgery, 19A: 1019 1026.
(a) Active flexion and (b) extensaon of the little finger 15 months after the operation.
Jupiter JB, Sheppard JE (1987). Tension wire fixation of avulsion fractures in the hand. Clinical Orthopaedics and Related Research, 214:113 120. Sarrafian SK, Kazarian LK, Topouzian LK, Sarrafian VK, Siegelman A (1970). Strain variation in the components of the extensor apparatus of the finger during flexion and extension. Journal of Bone and Joint Surgery, 52A: 980-990.
Received: 31 July 1996 Accepted after revision: 30 September 1996 K. Watanabe MD, Gifu Prefectural Tajimi Hospital, 5-161 Maehata-cho, Tajimi, Gifu 507, Japan. © 1997 The British Society for Surgery of the Hand
AVULSION OF THE EXTENSOR THE LITTLE FINGER
APPARATUS
OF
K. WATANABE, T. U R A S A K I and J. N I S H I K I M I
From the Department of Orthopaedic Surgery, Gifu Prefectural Tajimi Hospital, TajimL Japan We report a case of simultaneous closed avulsions of the terminal extensor insertion and the central slip of the little finger which required operative treatment.
Journal of Hand Surgery (British and European Volume, 1997) 22B: 2:281-282 Closed avulsions of the terminal extensor tendon insertion or the central slip of a finger are common injuries, resulting in mallet deformity and boutonni6re deformity, respectively. Each injury usually occurs in isolation. We present a case of simultaneous closed avulsions of both tendon attachments. To our knowledge there has been no previous report of this type of injury in the literature. CASE REPORT
A 57-year-old man caught his gloved hand in a drill which forced the interphalangeal (IP) and metacarpophalangeal (MP) joints of his fifth finger into excessive flexion. Active flexion of the IP joints was possible, although restricted by severe pain. Active extension was absent (Fig 1). X-rays showed significantly displaced avulsion fractures from the dorsum of the bases of both the distal and middle phalanges, i.e. the insertions of the terminal tendon and the central slip (Fig 2). At exploration 2 days after injury, the extensor apparatus was found to be avulsed from the distal and middle phalanges with a distal laceration of the ulnar lateral band. The avulsed fragments were reduced and fixed with the tension band wire technique (Jupiter and Sheppard, 1987), and the ulnar lateral band was sutured to the radial lateral band. Kirschner wires (1.1 mm) were used to maintain the IP joints in extension for 4 weeks, and the MP and wrist joints were splinted in extension for 3 weeks after the operation. Protected motion was begun after removal of the wires. Fifteen months after the injury, X-rays showed bony union
Fig 2
X-ray showing avulsion fractures from the dorsum of the bases of the distal and middle phalanges.
(Fig 3). The range of flexion of the little finger was 20 to 35° at the distal IP joint, 5 to 70 ° at the proximal IP joint, and minus 5 to 100° at the MP joint (Fig 4). The patient was pain-free in normal everyday activities and satisfied with the functional result. DISCUSSION
Fig 1
Avulsion of the extensor tendon at the insertion of the phalanx is usually caused by sudden forceful flexion of the extended finger. In this case, the mechanism was forceful and excessive flexion of both the IP joints. Sarrafian et al (1970) have described that the peak strain on the terminal tendon is during the initial phase of flexion, and that the peak strain on the central slip occurs just before full flexion. These experimental results suggest that avulsion of the terminal tendon occurred initially, followed by avulsion of the central slip. Since there was significant displacement of both small fragments operative treatment was indicated. Tension band wiring, although not effective for very small
The little finger after the hyperflexion injury. 281
282
T H E J O U R N A L O F H A N D S U R G E R Y VOL. 22B No. 2 A P R I L 1997
Fig4
Fig 3
X-ray showing bony union of both the avulsed fragments 15 months after the operation.
f r a g m e n t s because o f p o o r m a i n t e n a n c e o f tensile forces (Bischoff et al, 1994), was utilised. A l t h o u g h the distal f r a g m e n t was very small, b o n y u n i o n was achieved. References Bischoff R, Buechler U, De Roche R, Jupiter J (1994). Clinical results of tension band fixation of avulsion fractures of the hand. Journal of H a n d Surgery, 19A: 1019 1026.
(a) Active flexion and (b) extensaon of the little finger 15 months after the operation.
Jupiter JB, Sheppard JE (1987). Tension wire fixation of avulsion fractures in the hand. Clinical Orthopaedics and Related Research, 214:113 120. Sarrafian SK, Kazarian LK, Topouzian LK, Sarrafian VK, Siegelman A (1970). Strain variation in the components of the extensor apparatus of the finger during flexion and extension. Journal of Bone and Joint Surgery, 52A: 980-990.
Received: 31 July 1996 Accepted after revision: 30 September 1996 K. Watanabe MD, Gifu Prefectural Tajimi Hospital, 5-161 Maehata-cho, Tajimi, Gifu 507, Japan. © 1997 The British Society for Surgery of the Hand