The patella, or kneecap, is a small but crucial bone situated at the front of the knee joint. It plays an important role in knee extension and protects the joint from injury. When this bone breaks, it is known as a patella fracture. These injuries can range from minor cracks to severe, displaced breaks, and their treatment depends on the type of fracture and its severity.
By Arete Orthopaedic Centre
Medically Reviewed by Dr Wang Lushun
Patella fractures commonly result from either a direct or indirect force to the knee. The most frequent cause is a direct blow, such as a fall directly onto the kneecap. A definitive diagnosis is made through a physical examination and imaging (typically X-rays), which can reveal the location, type and displacement of the fracture. The symptoms of a patella fracture often include:
Patella fractures are typically classified based on the fracture pattern and whether the bone fragments have remained in place.
In this type of fracture, the bone fragments remain in their correct position and maintain contact. The crack in the bone may be minor, and the knee's extensor mechanism (the quadriceps tendon, patella and patellar tendon) remains intact. The patient can often still straighten their leg, although doing so may be painful.
A displaced fracture occurs when the bone fragments move out of alignment and separate from each other. This separation may be visible or felt as a gap in the kneecap. Because the knee’s extensor mechanism is disrupted, the patient is unable to straighten their leg.
A comminuted fracture is a severe injury in which the patella shatters into three or more fragments, significantly compromising knee function.
There are two main forms of comminuted fractures:
A transverse fracture is one of the most common types of patella fractures, occurring when the bone breaks into two pieces along a horizontal line. This creates a clear break across the middle of the kneecap. The fracture can be either stable (non-displaced), where the bone fragments remain aligned, or unstable (displaced), where the fragments shift out of position, making it impossible for the patient to straighten their leg.
A vertical fracture is less common than a transverse fracture and runs along the length of the patella, from top to bottom. These fractures are often non-displaced and stable because the surrounding soft tissues help hold the bone fragments in place. As a result, patients can usually straighten their leg, though it may still be painful.
The treatment for a patella fracture is determined by the type of fracture, the degree of displacement, and the patient's overall health and activity level. The primary goal is to restore the knee's extensor mechanism, allowing the patient to regain full function and strength.
This approach is typically reserved for stable, minor, non-displaced fractures. The principle is to allow the bone to heal naturally while protecting the knee joint.
Surgical intervention is the standard of care for displaced and comminuted patella fractures. The primary objectives are to realign the bone fragments and secure them in place to allow for healing and early mobilisation.
Recovery after a patella fracture varies depending on the severity of the injury and the type of treatment received.
If you experience persistent knee pain, swelling or difficulty moving your leg, please seek prompt medical care. Our orthopaedic doctor provides expert evaluation and personalised treatment plans to help you heal effectively and regain mobility. Contact us today to book an appointment.
MBBS (S’pore), MRCS (Edin), MMed (Ortho), FRCS (Ortho) (Edin)
With over 18 years of experience, Dr Wang Lushun is an orthopaedic surgeon who specialises in treating a wide range of sports injuries and musculoskeletal conditions. He has in-depth experience in minimally invasive surgery and advanced robotic surgery. Dr Wang provides orthopaedic care to athletes and everyday individuals throughout their journey to recovery.
