3 DECEMBER 2021 ausdoc . com . au the testosterone kicks in and young males do dangerous things . 6
In the toddler population , there is usually an undisplaced greenstick fracture — typically a torus fracture where the bone bends with a bulge that would look like a doughnut in cross section . Because the periosteum is intact , the overall architecture of the bone is intact . These injuries are distant from the growth plate . Forearm fractures have relatively little effect on longitudinal growth and can be minimally symptomatic .
The hallmark / diagnostic sign is the toddler who will not use one arm , so a toy or food placed on the affected side of the high-chair tray will be picked up with the contralateral hand . Careful examination reveals tenderness over the distal radius as opposed to anywhere else . The fracture itself is not palpable in these chubby arms , and because the corticoperiosteal envelope is not disrupted , there is minimal bruising .
Treatment is generally symptomatic . In an acute and obviously painful injury , an above-elbow cast protects against reinjury and provides pain relief . Below-elbow casts tend to fall off short arms . Modern waterproof casting materials — typically with a polyester resin and a hydrophobic fabric liner — allow bathing and are surprisingly comfortable compared with the older plaster cast or fibreglass , which could get quite itchy and sharp .
If the child is seen again after a week , they will generally have started to use the arm again as union is already occurring , so there may be no need for casting . The author usually advises parents to keep the child away from whatever originally caused the injury . If the parent appears particularly distraught and is having difficulty controlling older siblings , there may still be a case for a short period of casting . A rule of thumb for casting is that two weeks is long enough for a two-year-old , three weeks for a six-year-old and four weeks for a 10-year-old . Midshaft fractures need about 50 % longer to unite . 7
The older the child gets the greater the tendency to have a Salter II fracture of the distal radius , with the displacement and angulation being proportional to the energy of the impact .
The author believes it good medical practice to give a child a general anaesthetic for a painful procedure , such as fracture reduction . Good casting technique is like any good manual trade , where there is an immediately visible difference in the work of an expert plasterer and an amateur . The major question is whether the reduction is anatomic , and if not , is it acceptable ?
We are becoming increasingly aware of the long-term sequelae of minor malunion . Almost all the distal radioulnar joint pathology the author sees in the 15-30-year-old group is a result of paediatric malunion . The author feels that modern internal fixation devices allow the fracture to be reduced perfectly with minimal scarring , as opposed to repeated attempts at reduction and casting . Plating will allow less time off school and limit later complications ( see figure 11 ).
PREVENTION Specific splints for snowboarding / skateboarding / rollerblading are
Table 1 . Salter – Harris classification of fractures Grade I
II
III
IV
V
Characteristics
The fracture goes through the growth plate This means there is no actual bone fragment visible on X-ray
The fracture goes through the growth plate , with a fragment of metaphysis attached to the epiphyseal fragment ( see figures 7 and 8 )
The fracture goes partway through the growth plate and then through the epiphysis into the joint ( see figure 9 ) This means the growth layer of cells is disrupted and there is articular incongruency
The fracture goes through the metaphysis , then partway through the growth plate , through the epiphysis and into the joint ( see figure 10 ) Not only is the joint incongruent and the growth layer of cells injured but there is a great risk of cross union if the epiphyseal fragment unites to the metaphysis or the metaphyseal fragment to the epiphysis
This fracture is radiologically indistinguishable from the Salter I on the first X-ray It represents a direct crush injury , severe enough to kill cells in the growing layer of the epiphysis This means either the bone will not grow , as a bony bridge forms between the epiphysis and the metaphysis , or that the bone will grow distorted
Figure 7 . The little finger base of proximal phalanx is abducted , typically from an attempted ball – catch or snagging on furniture . The Salter II fracture has a tiny metaphyseal fragment and a widened growth plate . This is easily reduced in the first few days , but rapid malunion prevents reduction beyond about a week in a 10-year-old .
available at sports stores . These have a stiff palmar bar , typically 3-5mm thick nylon . They are much stronger than ‘ medical ’ splints because they are designed to be fallen on .
Motocross splints use a dorsal bar and are ideal for gripping handlebars . More expensive than volar splints , they are articulated to allow throttle use . They decrease the risk of radial and scaphoid fractures significantly in falls from motorbikes / mountain bikes and can be worn over gloves , which protect against abrasion . 8-10
Splints , like helmets and seatbelts , only work when they are strapped on firmly .
REMODELLING Longitudinal limb growth is genetically determined , and when a bone is deformed by a fracture , it has a natural tendency to recover to its normal anatomy .
In a neonate , a 90 ° angle can remodel in a few weeks because the baby has doubled in size . A twoyear-old is half of their adult height ,
Figure 8 . Salter II fracture in a seven-year-old boy . Closed reduction is stable , with buddy taping and a thermoplastic splint to protect against re-injury . Despite gross angulation , the chance of growth arrest is less than 1 %.
so there is much less potential for growth . Many 10-year-old girls and 12-year-old boys are completely skeletally mature . Hands and feet stop growing a year or two before the child reaches full height , with a final growth spurt often noted by outgrowing two pairs of school shoes in a year .
The general principle is that a malunion close to a growth plate , in the same plane as the major movement of the joint , can remodel if there is enough growth remaining .
This means that a 10 ° dorsally angulated distal radial malunion in a fiveyear-old will almost certainly correct over the next two or three years . A 10 ° radial / ulnar angulatory malunion may never correct . Rotational malunion does not correct nor does articular incongruency .
Forearm rotation occurs at the body ’ s most unusual joint . It is a bicondylar joint ( as is the knee ), but one condyle is the radial head at the elbow , and the other condyle is the ulnar head at the wrist . In PAGE 28