Patella Fracture Flashcards
How common are patella fractures?
Patella fractures account for approximately 1% of all skeletal injuries and are most prevalent in 20-50 year olds. They are twice as common in males.
Briefly describe the anatomy of the patella
The patella itself is the largest sesamoid bone in the body, formed within the tendon of the quadriceps femoris muscle as it crosses over the anterior aspect of the knee joint, attaching to the patellar ligament inferiorly. Its posterior surface consists of medial and lateral facets that articulate with their respective femoral condyles.
What are the clinical features of a patella fracture?
Patients will present with anterior knee pain, following a mechanism of injury such as a hard blow to the patella (e.g. dashboard injury in a RTA) or strong contraction of the quadriceps.
The pain will be made worse with movement and the patient will be unable to straight leg raise (due to damage to the extensor mechanism). They may not be able to weight bear.
On examination, the affected knee will be significantly swollen and bruised. Often a visible and palpable patellar defect is present between the bone fragments.
What investigations should be ordered for a patella fracture?
The mainstay of investigation for suspected patella fracture is plain film radiographs, obtaining three separate views (antero-posterior, lateral, and skyline).
More advanced imaging (usually CT) is indicated in comminuted fractures or in cases not overtly apparent on plain films but clinically suggestive.
Briefly describe the AO Foundation Classification
The AO Foundation Classification classifies patella fractures into three groups (1) extra-articular or avulsion fractures (2) partial articular fractures (3) complete articular fractures.
