Presentation
Tripped over a construction cable while walking causing him to fall directly onto his right knee. Patient presented with progressive swelling and pain and only able to partially weight bear. Physical Examination - pre-patellar swelling with minimal tenderness to medial aspect of knee and patella with limited active/passive range of movement.
Patient Data
Nil acute bony injury. A linear lucency noted to the lateral aspect of the patella in keeping with a bipartite patella.
Case Discussion
A bipartite patella (two-part patella) is a patella with an unfused accessory ossification center. It is usually discovered incidentally. However, 2% of patients with bipartite patella experience symptoms such as anterior knee pain, especially after trauma (as with this patient), sports injury, or overuse.
There are three types of Bipartite Patella:-
- type I: inferior pole ~1%
- type II: lateral margin ~20-25%
- type III: superolateral portion ~75% (as with this patient)