A healthy 11-year-old boy landed on his trampoline and complained immediately to his parents of bilateral knee pain. He was jumping vertically straight up and down at the time and no other person was on the trampoline. He had no significant past medical, drug, or family histories. He specifically had no history of anterior knee pain nor was he hypermobile (Beighton score 0). He attended hospital with bilateral knee pain with significant effusions, the left being larger clinically than the right (Figure 1). Radiographs of the knees were suspicious of sleeve fractures (Figures 2(a)-2(d)) and an MRI of both knees was organised. The MRI clearly revealed the extent of the displaced sleeve fractures (Figure 3).
He underwent open reduction and internal fixation of the injuries within 24 hours. A midline incision was used. The paratenon was incised in the midline and dissected off the proximal few centimetres of the proximal patellar tendon and the fracture site defined. The knee then underwent a copious lavage. Three transosseous tunnels were drilled in the coronal plane with a 2.5 mm drill. Number 5 Ethibond was then used to anatomically oppose the ends of the sleeve fracture. The construct was reinforced with a circlage wire, passing through the tibial tuberosity and above the superior pole of the patella, with the wire twisted so that it could be retrieved later through a small incision (Figures 4(a) and 4(b)). The torn extensor retinaculum was then repaired using absorbable sutures.
Postoperatively, the legs were immobilised in lightweight casting material in extension for a period of 6 weeks nonweightbearing. Followed by a hinged knee brace for 6 weeks, gradually increasing the range of motion and weight bearing status. Had the injury been unilateral then he would have been FWB in extension from surgery. The circlage wires were subsequently removed uneventfully at 6 months, prior to this he had regained full symmetrical range of motion (0-135 degrees) and was pain-free. He was allowed to return to full activity 6 weeks after removal of the circlage wires during which time he attended physiotherapy.