title: Snapping popliteus tendon in a 21-year-old female.
abstract: METHODS
  Case report.
  
  
  BACKGROUND
  Determining the cause of painful snapping on the lateral aspect of the knee can be a challenge. The differential diagnosis includes iliotibial band friction syndrome, lateral meniscus tear, intra-articular loose body, discoid lateral meniscus, snapping biceps femoris tendon, degenerative joint disease, proximal tibiofibular joint instability, and snapping popliteus tendon.
  
  
  METHODS
  A 21-year-old female presented with a 7-year history of a painful snapping on the lateral aspect of her left knee. She reported the snapping occurred with all activities involving knee flexion and extension, including running and walking. With a diagnosis of snapping iliotibial band, she had received a variety of physical therapy interventions, including various lower extremity stretching and strengthening exercises. Nonsteroidal anti-inflammatory medications were also prescribed by her physician. Conservative and pharmoclogical interventions were unsuccessful in improving her symptoms. Similarly, our attempt with conservative treatment consisting of ice, taping, and a short period of immobilization was not successful.
  
  
  RESULTS
  The patient underwent a surgical procedure consisting of removal of a prominent tubercle on the lateral femoral condyle and tenodesis of the popliteus tendon to the proximal aspect of the fibular (lateral) collateral ligament, followed by a postoperative program of physical therapy including range-of-motion and progressive strengthening exercises. At 6 weeks following surgery, the patient had returned to all activities with complete resolution of her symptoms.
  
  
  CONCLUSIONS
  Painful snapping at the lateral aspect of the knee may be caused by a variety of disorders, including the popliteus tendon. Clinical diagnosis is challenging. Clinical suspicion of a snapping popliteus tendon as a source of the signs and symptoms of the condition is important for inclusion in the differential diagnosis.
  
  
  METHODS
  Differential diagnosis, level 4.
authors.affiliation: Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA. krause.david@mayo.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Krause
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stuart
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008022:Ligaments / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D017063:Outcome Assessment, Health Care; D010146:Pain / Q000601:surgery; D013710:Tendons / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery