Patella fracture repair restores the broken kneecap and the extensor mechanism of the knee. The procedure is reserved for displaced fractures and fractures in which the extensor mechanism is disrupted, where non-surgical treatment would produce significant functional loss. Treatment depends on fracture pattern, displacement, and bone quality.
What Is Patella Fracture Repair?
The patella is a sesamoid bone within the quadriceps tendon, functioning as a pulley for the extensor mechanism that straightens the knee. Patellar fractures occur from direct blows to the front of the knee or from forceful eccentric quadriceps contraction.
Surgical fixation depends on the fracture pattern:
- Tension band wiring: indicated for transverse fractures with displacement; uses parallel pins or screws with a figure-of-eight tension band wire that converts tensile force across the fracture into compressive force during knee extension
- Screw fixation: indicated for vertical or partial fractures; uses lag screws to compress the fragments
- Plate fixation: indicated for comminuted fractures with multiple fragments; uses a contoured plate with multiple screws
- Partial patellectomy: indicated when severely comminuted lower pole fragments cannot be reconstructed; the small comminuted fragments are removed and the patellar tendon is repaired to the remaining patella
Total patellectomy is avoided whenever possible because it significantly weakens the extensor mechanism.
Who Is a Candidate?
Candidates for surgical repair typically have:
- Displaced fractures (more than 2 to 3 mm displacement or 1 to 2 mm articular step-off)
- Fractures with disruption of the extensor mechanism (inability to actively extend the knee or maintain a straight leg)
- Open fractures (an emergency)
- Failed non-surgical treatment with persistent fracture displacement or nonunion
Non-displaced fractures with intact extensor function are treated non-surgically with bracing in extension.
How the Procedure Is Performed
The procedure is performed through a vertical or curved incision over the front of the knee. The fracture is exposed and any blood clot is removed. The fracture surfaces are cleaned and the fragments are reduced anatomically with attention to both bone alignment and the articular surface.
Fixation is then applied based on fracture pattern. For tension band wiring, two parallel pins or cannulated screws are placed across the fracture, with a figure-of-eight wire passed around them on the front of the patella. For screw fixation, lag screws compress the fragments. For plate fixation, a contoured plate is applied to the front of the patella with multiple screws.
The extensor mechanism (quadriceps tendon, retinaculum, patellar tendon) is repaired if disrupted. Active extension is tested before closing.
Recovery and Rehabilitation
Recovery follows a protected protocol:
- Brace immobilization in extension for two to four weeks with early gentle range of motion
- Progressive weight-bearing and motion over the following month
- Strengthening at six to eight weeks
- Return to most daily activities by three months
- Return to sport at four to six months
Early motion within safe ranges helps prevent stiffness, the most common complication.
Risks and Outcomes
Risks include hardware irritation (a common late complication often requiring removal after union), nonunion, malunion, stiffness, and post-traumatic patellofemoral arthritis. Outcomes are generally good when the fracture is anatomically reduced and the extensor mechanism is restored.
Comminuted patellar fractures have higher rates of post-traumatic arthritis because of the articular damage at the time of injury.
Why Dr. Chudik for Patella Fracture Repair
Dr. Chudik treats the full range of extensor mechanism injuries, from patellar fractures to associated quadriceps and patellar tendon ruptures. His experience across the spectrum of knee pathology informs implant selection and surgical sequencing in complex cases. For severely comminuted fractures, his approach prioritizes preserving as much native patella as possible to maintain extensor mechanism function.