Keywords:
Trauma, Outcomes, Epidemiology, Surgery, Physiological studies, Health policy and practice, MR, Digital radiography, Conventional radiography, Musculoskeletal soft tissue, Musculoskeletal joint, Bones
Authors:
S. M. Crilly1, J. Ryan2; 1Perth/AU, 2Dublin/IE
DOI:
10.1594/ecr2018/C-0707
Results
Case report: We present the case of a 6 year old male who whilst jumping on a trampoline suffered an injury to his left knee.
He has no past medical history of note,
no allergies and no heritable risk factors for musculoskeletal disease.
On examination at time of clinic visit his knee was swollen,
painful on passive extension and he was unable to fully extend his knee (hence it was imaged in a flexed position,
see MR images).
Plain film imaging of the joint at an outside hospital were reported as normal,
but,
the patient was swollen and unable to weight bear,
therefore his plain film imaging was review at our institution and he also underwent additional MR imaging here.
His plain film imaging demonstrated a Salter Harris Type II fracture of the proximal tibia (figure 4).
He underwent MR imaging of the left knee,
Proton density (PD) and T2 fat saturation sequences were performed.
The growth plate is widened and oedematous and there is a fracture through the anterior aspect of the metaphysis (figure 5),
as well as more diffuse marrow oedema involving the metaphysis suggesting more widespread metaphyseal injury.
Notably, there is a low signal linear structure entrapped within the posterior aspect of the fracture. This is thought to represent one of the components of the distal semimembranosus tendon which is torn. To the authors knowledge this is the first such report of childhood Salter Harris II fracture with insertion of an avulsed tendon into the epiphyseal growth plate.
Epidemiology of Paediatric trampolining injuries
- Male:Female injury rates are largely similar.
- 10-12 age group have highest injury rates.
- Estimated to account for 3% of US paediatric hospital admissions,
and between 3-14% of UK paediatric hospital admissions.
- Extremity injuries are the most common; lower 36%,
upper 31.8%.
- Falls from trampoline are most common mechanism of injury (27-39%),
and are associated with increased severity of injury.
- Rotational manoeuvres such as flips and somersaults are associated with C-spine injury,
most commonly at C5/C6.
- Home use vs trampoline park: injury rates are similar between both but mechanism and location differ somewhat.
Management strategies for injuries for the PMC vary considerably and depend largely upon the extent of damage to the remainder of the knee ligaments and their relative contribution to knee dynamic stability.
However,
the general rule follows that PMC corner injuries are more likely to occur in concert with Posterior Cruciate Ligament (PCL) injuries and in these cases primary repair of the PMC structures should be considered,
as failure of repair of the PMC can result in ongoing knee instability in cases of mild to moderate (incomplete) PCL injuries.
Figure 7 demonstrates AMRI; the tibial anterior rotation that occurs as a result of damage to the PMC,
with anterior subluxation of the medial tibial plateau relative to the distal femur.
This can lead to dynamic instability of the knee when going from a flexed knee position into extension.