Bipartite Patella Q68.2 755.64

bipartitie patella AP

bipartitie patella

synonyms: bipartite, tripartite patella

Bipartite Patella ICD-10

  • Q68.2:    Congenital deformity of knee

Bipartite Patella ICD-9

  • 755.64 (congenital deformity of knee joint): absence of patella, genu valgum, genu varum, rudimentary patella

Bipartite Patella Etiology / Epidemiology / Natural History

  • Failure of ossification of complete ossification of the patella.
  • Occurs in 2-6% of the population.
  • 50% will be bilateral
  • Male:female = 9:1

Bipartite Patella Anatomy

  • The patella is the largest sesmoid bone in the body.
  • Primary ossification center appears to 4-6 years old. Secondary centers at 12 years old.

Bipartite Patella Clinical Evaluation

  • Generally asymptomatic. 2% symptomatic.
  • Generally men <20years old involved in sports.
  • Anterior knee pain. May initially become symptomatic after an injury. Worse with squatting, climibing stairs
  • May have localized tenderness on exam.
  • Trauma can cause the fragment to separate through a fibrous union.

Bipartite Patella Xray / Diagnositc Tests

  • Generally easily identified on plain knee films.
  • If separation has occurred after trauma the space between the fragments will increase in the squatting position (get skyline view in squatting position)
  • Bone scan: low specificity for symptomatic bipartite patella. 81% of asymptomatic patients will have increased uptake. (Oohashi Y, Knee Surg Sports Traumatol Arthrosc 2007;15:1395)
  • MRIL fat-suprressed T2-Weighted images may demonstrate bone marrow edema in the bipartite fragment in symptomatic patients.

Bipartite Patella Classification / Treatment

  • Saupe Classification: Type I:inferior pole of the patella (5%). Type II:lateral margin (20%). Type III:superolateral pole (75%) (Saupe H, Deutshe Z Chir 1943;258:386).
  • Conservative: rest, reduced sports, NSAIDs, quad stretching, dynamic patellar brace
  • Surgery: Small fragments can be excised. (Bourne MK,  J Pediat Orthop 1990;10: 69-73): Lateral retinacular release if non-op treatment fails. (Mori Y,Am J Sports Med 1995;23:13-18): vastus lateralis release: ORIF

Bipartite Patella Associated Injuries / Differential Diagnosis

  • Patella Fracture
  • nail-patella syndrome

Bipartite Patella Complications

  • Patellar instability
  • Incomplete relief of pain
  • Nonunion

Bipartite Patella Follow-up Care

Bipartite Patella Review References