Bipartite patella is the failure of the ossification centers of the patella to fuse. There are three types of bipartite patella (published data): the inferior pole, lateral margin, and superolateral pole.
An example of bipartite patella at the superolateral pole; the accessory ossification center at the superolateral pole remains unfused. On an x-ray, you will be able to see that the patella consists of two bones, the smaller part is the unfused segment and it is rounded and usually located laterally—this can be confused with a fracture.
It is often asymptomatic and an incidental findings, causing symptoms to mimic those of a fracture. Minor trauma or injury can cause the fibrous tissue to become inflamed and irritated.
Treatment of bipartite patella consists of:
- Rest
- Knee immobilizer
- Physiotherapy
- NSAIDs
If the fragment is small and very painful, you can excise the fragment. If the fragment is large, painful, and conservative treatments have failed, you can perform a lateral release of the retinaculum to reduce the traction force if needed. Very rarely, it may be necessary for an internal fixation and bone graft if the fragment is large.
