By Jessica Jahoda, Corey Steinman, Jonathan Kwok, William Duggan, Tyler Price, Brant Grisel
An eleven-year-old girl with an unremarkable medical history presents with severe right knee pain after falling from a bike and landing on her flexed knee. She presented to the ER with swelling, severe tenderness along the knee joint, and a palpable gap at the inferior border of the patella. Intact skin in this area indicates no signs of open fracture. The patient had an extension lag of 35-40 degrees. Passive range of motion was preserved with pain throughout an arc of motion. No neurovascular deficit in the right lower limb was noted. Lateral knee X-Ray and CT scan revealed high-riding patella with joint effusion and an osteochondral fragment distal to the patella, confirming a patellar sleeve fracture diagnosis. Surgical intervention is not required if the fracture is nondisplaced, displaced less than 3 mm, or if the extensor mechanism is intact.
In this scenario, operative management was indicated secondary to displacement of the fracture with disruption of the extensor mechanism. The patient underwent an ORIF with stabilization of the fracture using a single headless interfragmentary screw. An above-knee cast was applied in 10 degree flexion for 6 weeks. Stitches were removed after two weeks. Post-operative wounds healed without complications. Repeat X-ray showed normal anatomical alignment of the fracture site and hardware in place. The cast was removed six weeks post-operative. X-ray showed completely healed fracturePatient recovered full ROM after a month of weight-bearing physical therapy. Two years postoperatively, the patient was symptom-free with no complications.
This diagnosis is challenging to make secondary to its subtle radiographic findings. It is a rarity, accounting for less than 1% of pediatric fractures easily missed by emergency physicians. Complications such as duplicated patella, quadricep muscle atrophy, or active extensor lag highlight the importance of early recognition of this fracture to ensure better outcomes.