• RATIONALE
    • Sinding-Larsen-Johansson syndrome (SLJS) is an osteochondrosis of the inferior patellar pole that typically affects adolescents and usually resolves with conservative treatment. Persistence into adulthood is rare, particularly when associated with symptomatic ossicle formation, and the optimal management of such cases remains uncertain.
  • PATIENT CONCERNS
    • A 21-year-old male recreational basketball player presented with chronic anterior knee pain persisting for 6 years, aggravated by kneeling and jumping, despite prior extensive conservative management during adolescence.
  • DIAGNOSES
    • Clinical examination revealed a firm, mobile swelling distal to the patella, with preserved motion and knee stability. Serial imaging demonstrated progression to a discrete ossicle at the inferior patellar pole, consistent with stage IV-B SLJS.
  • INTERVENTIONS
    • Surgical excision of the symptomatic ossicle was performed through a midline approach with minimal patellar tendon disruption. Bone wax was applied to the exposed cancellous surface of the patella.
  • OUTCOMES
    • Postoperative recovery was uneventful. The patient achieved early mobilization, regained full function by 1 month, and experienced complete resolution of symptoms. Histopathology confirmed benign mature bone.
  • LESSONS
    • This case demonstrates that adult persistence of SLJS with ossicle formation, though exceptionally rare, may require surgical excision when conservative therapy fails. Careful resection with preservation of the extensor mechanism can provide reliable pain relief and restoration of full function.