What is the diagnosis and treatment for an 11-year-old girl with a 3-month history of left knee pain, worsened by jumping, and a tender palpable hard lump at the insertion of the patellar tendon?

Diagnosis: Osgood-Schlatter Disease

This 11-year-old girl has Osgood-Schlatter disease (OSD), a traction apophysitis of the tibial tuberosity where the patellar tendon inserts, and should be treated with activity modification, relative rest from jumping activities, and a structured physical therapy program emphasizing eccentric quadriceps strengthening. 1, 2

Clinical Diagnosis

The diagnosis is clinical and does not require imaging in typical presentations:

• Tender palpable hard lump at the patellar tendon insertion on the tibial tuberosity is pathognomonic for OSD 1
• Pain worsened by jumping and activities that load the patellar tendon (like ballet jumps) is characteristic 1, 2
• Occurs during periods of rapid growth (she grew 2 inches in 4 months), typically ages 10-15 in girls 1, 2
• The insidious onset over 3 months with load-related pain fits the typical presentation 3, 1

Imaging is unnecessary for diagnosis but may be obtained if the diagnosis is unclear: Plain radiographs in acute stages show soft tissue swelling and blurred patellar tendon margins; after 3-4 months, bone fragmentation at the tibial tuberosity appears 1

Treatment Algorithm

Phase 1: Initial Management (First 4-6 Weeks)

• Relative rest from aggravating activities, particularly jumping in ballet class - she should modify participation to avoid movements that reproduce pain 3, 4, 2
• Critical: Avoid complete immobilization or casting, as this causes muscular atrophy and deconditioning 4, 5
• Ice application through a wet towel for 10-minute periods for acute pain relief 4
• NSAIDs (oral or topical) for short-term pain control if needed, though they don't affect long-term outcomes 4
• Patient and parent education that this is a self-limiting condition lasting 12-24 months 2

Phase 2: Progressive Rehabilitation (Weeks 4-12)

• Eccentric quadriceps strengthening exercises are the cornerstone of treatment - these reduce symptoms, increase strength, and promote tendon healing by stimulating collagen production 4, 5
• Progressive stretching of quadriceps and hamstrings 6, 4
• Deep transverse friction massage may provide additional pain relief 3, 4
• Gradual return to modified ballet activities as pain allows, avoiding full jumping until symptoms resolve 2

Phase 3: Return to Full Activity (3-6 Months)

• Sport-specific exercises with gradual progression back to full ballet participation 6
• Maintenance strengthening program to prevent recurrence 6
• Approximately 80% of patients recover completely within 3-6 months with appropriate conservative treatment 4

When to Consider Surgery

Surgery is indicated only after 3-6 months of well-managed conservative treatment has failed and symptoms remain intolerable 4, 7

Surgical options include:

• Open or arthroscopic excision of unresolved ossicles and surrounding bursa 1, 8, 7
• Tubercleplasty to smooth the bony prominence 7
• Repair of patellar tendon to bone using suture anchors 7

Critical Pitfalls to Avoid

• Never inject corticosteroids into or near the patellar tendon, as this inhibits healing, reduces tensile strength, and predisposes to spontaneous rupture 4
• Do not allow complete cessation of all activity - maintain activities that don't reproduce pain to prevent deconditioning 3, 4
• Watch for tibial tuberosity avulsion fracture if patient experiences sudden severe pain after forceful activity, as OSD weakens the apophysis 9
• Avoid allowing return to full jumping activities before adequate quadriceps strengthening, as continued stress on weakened bone can worsen fragmentation 1, 9

Long-Term Considerations

• Symptoms typically resolve after growth plate closure 1, 8
• Some patients may have persistent prominence on the anterior knee or painful kneeling long-term 2
• The condition is generally benign and self-limiting over 12-24 months 2