Patella Fracture Treatment
The kneecap is the largest sesamoid bone in the body, meaning a bone embedded within a tendon, and it sits at the front of the knee where it protects the joint and gives the quadriceps its leverage. A fracture of the kneecap is uncommon, and it is significant out of proportion to its size, because breaking it interrupts the mechanism that straightens the leg.
Steven Struhl, MD is board certified in orthopedic surgery and separately in sports medicine, has practiced in New York since 1991, and serves as an attending surgeon at NYU Hospital for Joint Diseases. A kneecap fracture is not only a broken bone, it is a disruption of the mechanism that straightens the leg, and whether that mechanism still works is the finding that decides between a brace and an operation.
How Patella Fractures Happen
- Direct Blow to the Kneecap: a fall onto the front of the knee or a dashboard injury in a collision, which is the most common mechanism.
- Forceful Quadriceps Contraction: the muscle pulling hard enough against a bending knee to break the bone it pulls through.
- Sports Impact: direct contact in collision sport or a hard fall onto a flexed knee.
- Osteoporosis: lowering the force required, particularly in older patients.
Patella fracture is more common in adult men and is uncommon overall relative to other fractures around the knee.
Patella Fracture Symptoms
- Pain at the Front of the Knee: immediate and severe, directly over the kneecap.
- Inability to Straighten the Knee: the finding that matters most, since it indicates the extensor mechanism is disrupted.
- A Palpable Gap: a defect felt across the kneecap where the fragments have separated.
- Rapid Swelling: blood filling the joint within minutes.
- Bruising: developing across the front of the knee.
- Inability to Walk: the knee buckling on any attempt to bear weight.
The straight leg raise is the test that decides the treatment. A patient who can lift the heel with the knee straight has an intact extensor mechanism, and one who cannot does not.
Diagnosis
Radiographs establish the fracture and the pattern, and a skyline view shows the kneecap in profile. It is worth noting that a bipartite patella, a normal variant in which the bone forms in two pieces, is sometimes mistaken for a fracture, and comparing with the other knee usually settles it. CT is used for complex or multi fragment patterns where the joint surface needs to be assessed in detail before surgery.
Non Surgical Treatment for a Patella Fracture
- Non Displaced Fractures: fragments still in position with the joint surface intact.
- Intact Extensor Mechanism: the ability to straighten the knee actively against gravity.
- Immobilization: a brace or cast holding the knee in extension for four to six weeks.
- Weight Bearing: generally permitted in the brace with the knee locked straight.
- Early Motion: introduced gradually once healing is established radiographically.
- Serial Radiographs: confirming the fragments have not separated during healing.
Patella Fracture Surgery
Displaced fractures and any fracture where the knee cannot be straightened are treated surgically, since the fragments will not come together on their own and the extensor mechanism has to be restored.
- Tension Band Fixation: the standard technique for transverse fractures, using wires and pins that convert the pull of the quadriceps into compression across the fracture.
- Screw Fixation: used alone or combined with a tension band in suitable patterns.
- Plate Fixation: applied in comminuted fractures with multiple fragments.
- Partial Patellectomy: removing a small fragment that cannot be reconstructed and reattaching the tendon.
- Total Patellectomy: rarely performed, and reserved for fractures where nothing is salvageable.
Rehabilitation After a Patella Fracture
- Weeks One to Six: the knee protected in extension, with weight bearing usually permitted in the brace.
- Weeks Two to Six: controlled motion started, with the range advanced as the fixation allows.
- Weeks Six to Twelve: brace discontinued, full motion restored, strengthening begun.
- Months Three to Six: quadriceps strength rebuilt toward the other side and return to most activity.
Some loss of terminal extension strength and occasional discomfort kneeling persist in a minority of patients. Hardware irritation is common enough that removal is sometimes requested once the fracture has healed, since the wires sit directly beneath thin skin.
Schedule a Kneecap Fracture Consultation in New York City
If you fell onto the front of your knee and cannot lift the leg straight, that is a specific finding and it should be evaluated the same week rather than treated as a bruise. Dr. Struhl treats knee fractures at his Manhattan and Westchester offices. Contact us to schedule an appointment.
