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Abstract
Ulnar collateral ligament injuries of the
thumb are extremely rare in children. If not detected and
repaired, it can lead to long-term instability of the
metacarpophalangeal joint (Smith, 1977). We report an injury
with a resultant tear of the ulnar collateral ligament in an
11-year-old boy after minor trauma.
J.Orthopaedics 2006;3(4)e25
Introduction:
Ulnar collateral ligament injury of the
thumb is well recognised in adults (Campbell, 1955). However it
is a rare injury in children with no cases reported before 1993
(Wallace & Carr). It is important to have a high index of
suspicion where the mechanism of injury is one of excessive
abduction force on the paediatric thumb, especially in the
absence of any bony injury.
Case Report
An 11-year old boy presented to the A & E
department following a fall from his bed. Inspite of the absence
of any bony injury, his discomfort and a history of his thumb
being ‘pushed over’ led to stress views being done. These showed
gross ulnar-sided instability at the metacarpophalangeal joint
of the thumb and a diagnosis of ulnar collateral ligament injury
was made.
The patient underwent an exploration of
the thumb the next day and a rupture of the ulnar collateral
ligament with a Stener lesion (Stener, 1962) was identified. The
ligament was primarily repaired by anchoring it to the thickened
periosteum and the thumb was immobilised in plaster for 3/52.
Four months later examination revealed normal function with a
stable MCP joint.
 Fig
1: Initial radiograph after injury
showing a normal appearance
Fig 2:Stress radiograph of the
thumb showing an injury to the ulnar collateral ligament
Discussion :
Ulnar collateral ligament injuries in the
paediatric population is a rare condition and can be easily
missed due to the minor discomfort exhibited by this group of
patients and the low diagnostic rate on standard plain
radiographs of the thumb. Clinicians tend to scan radiographs
for an epiphyseal fracture and in its absence tend to label the
injury as a ‘strain’ or ‘sprain’ of the thumb.
If the mechanism of injury is suggestive
then a thorough examination should be carried out with stress
views of the thumb under local anaesthesia and in some cases an
examination under a general anaesthetic may
be necessary. If missed these injuries can lead to long-term
instability of the metacarpophalangeal joint of the thumb.
We emphasise the importance of having a
high index of suspicion to diagnose these injuries since they
are amenable to repair with good results (Derkash, 1987) in this
age group.
Reference :
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Smith. RJ (1977). Post traumatic instability
of metacarpophalangeal joint of the thumb. Journal of Bone and
Joint Surgery, 59A: 1;14-21.
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Campbell CS (1955). Gamekeeper`s thumb.
Journal of Bone and Joint Surgery, 37B: 148-149.
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Wallace DA, Carr AJ (1993). Rupture of the
Ulnar Collateral Ligament of the thumb in a 5- year old girl.
Journal of Hand Surgery, 18B: 501.
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Stener B. (1962). Displacement of the
ruptured ulnar collateral ligament of the metacarpophalangeal
joint of the thumb: A clinical and anatomical study. Journal of
Bone and Joint Surgery, 44B: 4; 869-879.
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Derkash RS, Matyas JR, Weaver JK et al.
(1987). Acute surgical repair of the skier’s thumb. Clinical
Orthopaedics and Related Research, 216; 29- 33.
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