<div>Title : surgical treatment for the uncommon bi-articular fracture of
trapezium: a case report</div><div>Abstract</div><div>Trapezium bone fracture is a rare condition that often goes undetected
and exposes to long-term comorbidities, including chronic pain and
rhizartrosis. In the presence of a very suggestive clinical presentation
with a normal radiograph, a CT scan of the wrist should be considered.
The therapeutic guidelines are not well established due to the lack of
series reported in the literature. Our work aims to is to enrich the
literature by reporting the case of a 37-year-old man who underwent open
reduction internal fixation with mini-screws for a displaced fracture of
the body of the trapezium with a satisfactory outcome.</div><div>keywords : carpus , trapezium bone , fracture , surgery , microscrews</div><div>Introduction</div><div>Hand bone fractures represent 18% of all fractures, of which carpal
bone fractures constitute 8%. Trapezium bone fractures are uncommon and
represent only 4% of all carpal bone fractures (1,2), and they are
often associated with a fracture of the base of the 1st metacarpal.
These fractures are mostly missed on conventional radiographs with only
18% sensitivity (3), leading to chronic pain of the thumb column, loss
in grip strength, and rhizarthrosis (4) if ignored.</div><div>The physical findings for this type of fracture are not accurate, and
usually mimic a scaphoid fracture, therefore, in case of inconclusive
radiographs, a CT scan is to be considered.</div><div>There are two main types of fractures of the trapezium, the avulsion
fractures of the tubercle of the trapezium, which serves as an
attachment to the flexor retinaculum, and the body fracture, which is
the most frequently found.</div><div>We are reporting the case of a 37-year-old male presented for a vertical
shape displaced fracture of the body of the trapezium, who has undergone
an open reduction internal fixation. Through this case, we describe the
surgical technique and the functional results; and we also present a
brief literature review.</div><div>Case presentation:</div><div>A 37-year-old right-handed male disc jockey, with no notable
pathological history,was involved in a traffic accident, and fell from
his motorcycle, landing on the palm of his left hand, hyperextended
wrist with radial deviation. On admission to the emergency room, the
patient presented a swollen wrist with a filled anatomical snuffbox,
exquisite pain on compression and rotation maneuver on the thumb column,
and palpation of the anatomical snuffbox. The radial artery and other
vascular examinations were normal. The hand radiographs showed a
vertical fracture of the body of the trapezium bone with a displacement
of more than 2 mm, with no associated comminution (figure 1). The CT
scan confirmed the absence of comminution and the absence of any other
associated carpal bone lesions. The patient was treated surgically by
open reduction and internal fixation with a single microscrew, a dorsal
approach was chosen (Figure 2) between extensors pollicis longus and
brevis, paying attention to the sensitive branches of the radial nerve
and the radial artery, the correct reduction of the articular surface
was checked through a longitudinal capsulotomy and fluoroscopic control.</div><div>Postoperative radiographs confirmed the accurate reduction of the
fracture (Fig. 3), and immobilization of the wrist and thumb column in a
cast was conducted for three weeks. At cast removal, self-education was
encouraged. The patient regained full mobility of the thumb column and
wrist after five weeks (Figure 4), with a return to work at seven weeks.
the full recovery of grip strength took nine weeks. No complications
were reported in our patient.</div><div>Discussion:</div><div>The trapezium bone is the most radial bone of the 2nd row of carpal
bones, it articulates with the scaphoid and trapezoid bones proximally
and forms a double saddle joint with the base of the 1st metacarpal
distally, providing the thumb a range of mobility in all axes. On its
palmar side, the trapezium bone has a central longitudinal crest, which
gives an attachment to the flexors’ retinaculum, it’s called the
trapezium ridge.</div><div>There are two distinct fractures of the trapezium bone (5); the body
fracture is the most common one, occurring as a result of a fall onto a
hyperextended wrist, with radial deviation and various degrees of
abduction of the thumb. The second type is the fracture of the trapezium
ridge, which is more unusual and follows a hyperextension of the wrist
or a straight impact to the anterior aspect of the trapezium bone, such
as a motorcycle handlebars injury. Trapezium ridge fractures are
subdivided into two types: Type I is the detachment of the base of the
tuber, while Type II is the detachment of the tip. Walker’s
classification describes 5 Types of trapezium body fractures, depending
on the fracture line and the involvement of the articular surfaces,
either carpometacarpal (CMC) or scaphotrapezial joint. Type I: fracture
with a horizontal line, Type IIa: fracture of the radial tuberosity with
involvement of the carpometacarpal joint, Type IIb: fracture of the
radial tuberosity through the scaphotrapezial joint, Type III: fracture
of the ulnar tuberosity, Type IV: fracture with a vertical line, Type V:
comminuted fracture (6).</div><div>The clinical presentation of a trapezium fracture is often similar to
that of a scaphoid fracture, with swelling and filling of the anatomical
snuffbox, ecchymosis, and pain at this level, in some rare cases, the
pain is at the anterior aspect, corresponding to a fracture of the
trapezium ridge, the pain is aggravated by compression and torsion of
the thumb column. Constrained flexion of the wrist, from the position of
the wrist in hyper-extension, may indicate a fracture of the trapezium
tubercle (5,7). The neurovascular examination is mandatory. One case of
radial artery involvement during a fracture of the trapezium bone has
been reported in the literature (8).</div><div>The standard radiographs of the hand front and side can be completed by
including a Kapandji incidence, with the wrist pronated at 15°, to
eliminate superposition of the trapezium bone with the remaining bones
of the carpus or a carpal arch incidence in case of a possible fracture
of the trapezial tubercle. However, the sensitivity of standard
radiographs for detecting trapezium fractures is still limited.
According to a study on 137 wrists with a trapezium fracture diagnosed
on CT, the sensitivity of radiographs for detecting this type of
fracture was only 18% (3). When a trapezium fracture is suspected with
inconclusive standard radiographs, it should be followed by CTscan or
cone beam imaging, which is less radiating and more accessible than a
CTscan and more sensitive than standard radiography (9).</div><div>Orthopedic treatment is proposed for a nondisplaced fracture of the body
or the tubercle of the trapezium (10). Surgical treatment is recommended
for displaced body fractures with more than 2 mm displacement. Open
reduction and internal fixation with a miniscrew or Herbert screw allow
an anatomical restoration of the articular surface with excellent
long-term functional outcomes (11).</div><div>Some authors suggest excision of the bony fragment in type I fracture of
the trapezium tuberosity because of the high incidence of pseudarthrosis
and chronic pain (5,12). Trapezectomy with or without suspension
ligamentoplasty remains a possible indication in elderly patients with
preexisting rhizarthrosis, whereas primary arthrodesis remains the only
alternative in young, active patients with a highly comminuted fracture.</div><div>The purpose of our work is to enrich the literature through the report
of our case, especially with the rarity of this type of fracture and the
lack of a series of studies that would allow us to reach a well-coded
therapeutic consensus. Surgical treatment of trapezium body fractures
allows anatomical restoration of the articular surfaces, thus achieving
a good functional outcome and preventing progression to rhizarthrosis
and chronic pain.</div><div>Conclusion</div><div>Isolated trapezium bone fracture is rare, which often goes unnoticed,
and this is not sequelae-free, it should be systematically searched for
before a clinical presentation simulating a scaphoid fracture,
especially when radiographs seem to be without abnormalities.</div>