Fracture of the patella

Cont.. Fig

Anatomy Largest sesamoid bone in the body. Quadriceps tendon inserted on the superior pole and the patellar ligament originates from the inferior pole. Funtion of the patella is to increase the mechanical advantage and protection.

Cont.. Fig

Mechanism of injury Direct trauma : Due to direct fall over the patella Usually cause comminuted fractures and are the common causes Indirect trauma (quadriceps contraction ): Sudden forceful contraction of the quadriceps (as in sports ) Age : common in 20 – 50 years age group

Clinical evaluation- Patient usually non ambulatory. Pain, swelling Abrasion over the patella. Unable to extend the knee Both the active and passive movements are restricted

On examination Palpable gap Tenderness signs of effusion Positive patellar

Classification Undisplaced Transverse fracture (80%) Vertical fracture Comminuted fracture Displaced Transverse (85 %) Oblique fracture Comminuted fracture osteochondral fracture

Classification Fig

Investigation X – ray : AP view lateral view Skyline view CT scan Bone scan MRI

Lateral view Fig :

Skyline view Fig

Tests : Patellar tap Fluctuation test

Patellar tapping Fig :

Treatment Non operative For non displaced fracture Cylinder cast: extending from the groin to just above the malleoli for 4 to 6 weeks. Followed by physiotherapy- quadriceps strengthening exercise.

Operative- Tension band wiring. (figure of 8) Patellectomy Partial:for proximal pole fracture; major fragment is preserved;. Complete: for comminuted fractures. Knee should be immobilized for 3 to 6 weeks in a long leg cast at 10degrees flexion for both partial and complete patellectomy.

Patella Knee Support Fig

Cont.. Open reduction and internal fixation for transverse fracture

Complications Refracture Non union Avascular necrosis of fragments Osteoarthritis Knee stiffness Patellar instability