Imaging for Osgood-Schlatter Disease
Start with plain radiographs of the knee as the initial imaging study for an 11-year-old girl with a tender, palpable, hard lump at the patellar tendon insertion. 1, 2
Initial Imaging Approach
Radiographs are the first-line imaging modality for any suspected musculoskeletal soft-tissue mass or knee pathology in this age group, as they can identify calcifications, bone involvement, fragmentation at the tibial tuberosity, and rule out other bony abnormalities 1, 2
Obtain anteroposterior and lateral views of the knee as a minimum two-view examination 1
Radiographs demonstrate positive findings in 62% of soft-tissue masses and can be diagnostic for specific conditions involving the patellar tendon insertion 2
In the setting of a palpable mass at the tibial tuberosity in an adolescent athlete, radiographs will typically show fragmentation, irregularity, or soft-tissue swelling at the insertion site consistent with Osgood-Schlatter disease 1
When Additional Imaging May Be Needed
Ultrasound is highly appropriate if radiographs are normal but clinical suspicion remains high, particularly for evaluating the patellar tendon itself, detecting tendinopathy, or confirming the relationship between the mass and adjacent structures 1, 2
Ultrasound has 94.1% sensitivity and 99.7% specificity for superficial soft-tissue masses and can differentiate solid from cystic lesions 2
MRI without contrast is reserved for cases where radiographs and ultrasound are inconclusive, there is concern for deep-seated pathology, or preoperative planning is needed 1, 2
MRI is not routinely used as the initial imaging study for acute knee conditions but provides superior soft-tissue characterization when needed 1
Clinical Context
The clinical presentation described (tender, palpable, hard lump at patellar tendon insertion in an 11-year-old) is classic for Osgood-Schlatter disease, a traction apophysitis of the tibial tuberosity 3
Palpation tenderness at the patellar tendon insertion is a reliable clinical finding (Pearson r = 0.82) but should be confirmed with imaging 4
The diagnosis remains primarily clinical, as asymptomatic tendon pathology may exist, but imaging helps confirm the diagnosis and exclude other pathology 3
Key Pitfalls to Avoid
Do not skip radiographs and proceed directly to advanced imaging—this violates standard imaging algorithms and increases costs unnecessarily 1, 2
Do not rely on physical examination alone, as it correctly identifies only about 85% of soft-tissue tumors 2
Avoid ordering MRI as the initial study, as it cannot adequately assess for calcification or bone involvement that radiographs readily demonstrate 1, 2