Clinical History
An 11-year-old boy attended the orthopaedic outpatient clinic complaining of pain in his left wrist. He had survived Meningococcal meningitis at the age of
8-years, albeit with the loss of several digits on both hands and feet.
Imaging Findings
An 11-year-old boy attended the orthopaedic outpatient department complaining of pain in the left wrist. At the age of 8-years, he had been severely ill with
Meningococcal meningitis, which necessitated a lengthy stay in the paediatric intensive care unit. As a complication of his illness, he suffered necrosis and spontaneous amputation of portions of
all of the digits of his left hand and several digits from the right hand and both feet. His hearing remained intact. He had been well in the interval, returning to his primary school, and recently
starting high school.
The pain in his left wrist had come on gradually over the past few months. There was no history of antecedent trauma. On physical examination, the left hand
was radially deviated. There was amputation through the proximal phalanx of the thumb and through the middle phalanges of the fingers of the left hand. Plain radiographs of the left wrist
demonstrated premature fusion of the distal radial growth plate.
Discussion
Premature epiphyseal fusion can result from trauma (fractures involve the growth plate in nearly 3 per 1000 children), infection, frostbite, radiation,
electrical injury, sensory neuropathy and scurvy1, 2. The mechanism is thought to be due to ischaemia. If the blood supply to the growth plate from the epiphysis is interrupted, then
damage to the growth plate can occur, resulting in it being replaced by a bony ridge1. When the bony ridge is large and centrally placed, growth is stopped and limb shortening results.
If the bony ridge is small and peripheral, then growth is tethered and angulation occurs. Both these possible outcomes can result in long term disability for the child involved; the younger the
child, the more severe the disability2.
In children who are less than one year old, the epiphysis is primarily cartilaginous. Metaphyseal blood vessels cross the growth plate and end in a spray
of vessels, located in the centre of the cartilage. These vessels provide most of the nutrition to the epiphyseal cartilage and it is thought that when there is a vascular insult at this stage,
central epiphyseal fusion results1.
Studies have shown that premature fusion of the epiphysis occurs more frequently in the lower than the upper limbs, and when it is due to trauma, it tends to
occur more distally2. Consequently, the knee and ankle have the highest incidence of growth arrest3.
The initial imaging for premature epiphyseal fusion is plain radiography. However, if the growth plate is not parallel to the x-ray beam, it can be difficult
to interpret the radiograph3. Typical appearances are a cone-shaped epiphysis or cupped metaphysis. Growth arrest lines are sometimes present, and if they extend across the metaphysis
parallel to the growth plate, then bridge formation is reported less likely3.
Magnetic Resonance Imaging is now the preferred imaging modality for the growth plate2, 3. Fat saturated spoiled gradient echo sequences and 3D
modelling of the growth plate can display areas of bone bridging and deformity, and help guide the surgeon3. When MR is not available, then CT utilising MPR and 3DVR techniques can also
demonstrate a bony bridge.
Management of premature epiphyseal fusion is surgical, and options include bridge excision (if the bridge measures less than 50% of the growth plate area),
with interposition of an inert material, epiphysiodesis for larger bridges and osteotomies to correct angular deformities2.
Differential Diagnosis List
Premature epiphyseal fusion as a sequel to Meningococcal meningitis
Final Diagnosis
Premature epiphyseal fusion as a sequel to Meningococcal meningitis
