Case contribution: Dr Radhiana Hassan
Clinical:
- A 71 years old man
- Underlying hypertension and IHD
- Complaint of right knee pain
- History of twisting knee with mild swelling
- Able to ambulate without aid
Radiographic findings:
- There is a well-defined linear line seen at superolateral aspect of right patella (yellow arrows) separating the patella.
- The line has well corticated bone borders
- No displacement of the bone fragment
- No associated soft tissue swelling at knee region
Diagnosis: Bipartite patella
Discussion:
- A bipartite patella is a patella with an unfused accessory ossification centre at the superolateral aspect.
- Prevalence of bipartite patella is about 2% of population
- It occurs bilaterally in about 43% of cases.
- It is more common in male than females.
- Mostly are asymptomatic but patient can present with knee pain after trauma or overuse.
- Different location: superoplateral portion (75%), lateral margin (20-25%) and inferior pole (1%).
- Differentiation with fracture; most common patella fracture is transverse (linear fracture is very uncommon), fracture commonly occurs after direct trauma to knee and volume of fracture fragment usually equivalent of normal patella
