A patella fracture, commonly known as a broken kneecap, is an injury to the small, flat bone at the front of the knee joint. The patella shields the knee, protecting underlying structures. It also connects the thigh muscles (quadriceps) to the shinbone (tibia), enhancing quadriceps power during leg extension. Fractures often result from direct impact, like a fall or car accident, or less commonly, from a sudden, forceful contraction of thigh muscles.
Recognizing a Patella Fracture
A patella fracture typically causes immediate, intense pain and swelling in the front of the knee. Bruising around the kneecap is also common shortly after injury. Many find it difficult or impossible to straighten their leg, hold it extended, or bear weight. Sometimes, a noticeable gap in the kneecap can be felt through the skin if bone fragments have moved significantly.
Medical professionals diagnose a patella fracture by asking about the injury mechanism and symptoms. A physical examination assesses for swelling, tenderness, deformities, and the knee’s ability to extend and bear weight.
Imaging studies confirm the diagnosis and determine severity. X-rays are the primary diagnostic tool, providing clear bone images and identifying fracture type and displacement. For complex situations or to evaluate cartilage/soft tissue damage, a computed tomography (CT) scan or magnetic resonance imaging (MRI) may be used.
Treatment Options
Treatment for a patella fracture depends on factors like fracture type, displacement, and the knee’s extensor mechanism integrity. Options range from non-surgical to surgical interventions.
Non-surgical treatment suits small, stable fractures with minimal bone displacement (typically less than a few millimeters). It’s also considered if the knee’s extensor mechanism remains intact, allowing leg straightening. Initial management involves immobilizing the knee, often in a cast or brace, for four to eight weeks to allow healing. Activity is restricted, and weight-bearing may be limited or avoided initially to protect the healing bone. Pain management, using over-the-counter or prescription medications, is also part of non-surgical care.
Surgical intervention is necessary for displaced fractures (fragments separated or misaligned by over two millimeters) or open fractures (bone broken through skin). Surgery is also indicated if the injury disrupts the knee’s extensor mechanism, affecting leg straightening. The goal is to realign and stabilize bone fragments to restore knee function.
Several surgical techniques are employed. Tension band wiring is a frequent choice for transverse fractures, using pins (Kirschner wires) inserted into bone fragments and connected with a figure-of-eight wire loop on the patella. This converts quadriceps pulling forces into compressive forces at the fracture site, promoting healing. Screw fixation uses screws, sometimes with plates or wires, to hold fragments together. Cannulated screws can also be combined with a tension band for enhanced stability.
If the kneecap is severely shattered into many small, unreconstructable pieces, particularly at one of its poles, a partial patellectomy may be performed. This procedure removes damaged bone fragments and reattaches the remaining patellar tendon to the preserved kneecap portion. Complete kneecap removal, a total patellectomy, is a rare last resort for extremely severe fractures, as it significantly impacts knee strength and motion.
The Recovery Journey
Recovery following a patella fracture, whether treated surgically or non-surgically, is a rehabilitation journey crucial for regaining full knee function. The timeline varies widely based on fracture severity, treatment method, and individual factors, often taking three to six months to return to most normal activities. Initial immobilization, typically for four to eight weeks, is common in both pathways.
Physical therapy (PT) usually begins once the fracture achieves sufficient stability, often one to six weeks after injury or surgery. Its focus is to restore knee range of motion, strengthen surrounding leg muscles, and reduce stiffness from immobilization. Early exercises may include isometric quadriceps sets (muscle tightened without joint movement) and gentle range-of-motion exercises like heel slides.
As healing progresses, the PT program advances to include strengthening exercises, such as straight leg raises, wall squats, and hip muscle targeting. Gradual increases in weight-bearing activities are introduced as tolerated, moving from partial to full. Stationary cycling may also improve endurance and range of motion.
Challenges during recovery include persistent knee joint stiffness and muscle weakness, particularly in the quadriceps, due to prolonged immobilization. Some individuals may experience post-traumatic arthritis (cartilage damage leading to pain and stiffness over time). Chronic pain in the front of the knee is another potential long-term issue. Pain management, using prescribed or over-the-counter medications, along with ice and elevation, helps control discomfort and swelling.
The ultimate goal is to achieve a return to pre-injury function, with many able to resume sports and other activities within three to four months, though full recovery can extend beyond this timeframe. Sometimes, continued knee brace use may be suggested for ongoing support if stiffness or weakness persists.