A patellectomy is a surgical procedure that removes part or all of the kneecap (patella). It’s considered a last resort when the kneecap is too damaged to repair, typically after a severe fracture that shatters the bone into multiple pieces. While surgeons today try to preserve the kneecap whenever possible, patellectomy remains a necessary option when other approaches fail.
Total vs. Partial Patellectomy
The two types of patellectomy differ significantly in how much bone is removed and how well the knee functions afterward.
A partial patellectomy removes only the damaged portion of the kneecap while keeping as much healthy bone as possible. This is the preferred approach because preserving even a single fragment of the patella substantially improves the knee’s ability to extend and bear force. When surgeons can keep at least three-quarters of the upper portion of the kneecap intact, biomechanical outcomes are notably better. The force needed to straighten the knee is lower when half or less of the patella is removed compared to taking out the entire bone.
A total patellectomy removes the kneecap entirely. This is reserved for cases where the bone has shattered into so many small fragments that none are large enough to stabilize with hardware. It’s also used for rare situations like failed prior surgical repair or bone infection.
Why a Patellectomy Is Performed
The kneecap sits inside the tendon that connects your thigh muscle to your shinbone, acting as a lever that increases the power of your leg when you straighten it. Removing it is a significant trade-off, so surgeons only recommend it when the alternatives are worse. The most common reasons include:
- Comminuted fractures: A break that shatters the kneecap into many small pieces, making it impossible to reconstruct with screws or wires.
- Failed prior repair: When a previous surgery to fix the kneecap didn’t hold or the bone didn’t heal properly.
- Severe arthritis: Advanced cartilage damage on the underside of the kneecap that hasn’t responded to other treatments.
- Infection: Bone infection (osteomyelitis) in the patella that can’t be controlled while the bone remains in place.
- Tumors: Growths in or around the kneecap that require removal of the bone.
When a kneecap fracture can be pieced back together, surgeons strongly prefer open reduction and internal fixation (ORIF), which uses wires or screws to hold the fragments in place while they heal. A study comparing the two approaches in patients with severely shattered kneecaps over 10 to 20 years of follow-up found that total patellectomy was a safe and reliable alternative when reassembling the bone wasn’t feasible, though it came with higher rates of calcification in the surrounding tissue.
What Happens During Surgery
After the damaged kneecap is removed, the surgeon’s main task is reconnecting the quadriceps tendon (coming from the thigh) to the patellar tendon (attached to the shinbone). These two tendons normally attach to the top and bottom of the kneecap, so without it, they need to be joined directly to each other or to any remaining bone fragment.
In a partial patellectomy, the tendons are reattached to the remaining piece of kneecap using strong, permanent sutures threaded through tunnels drilled in the bone. In a total patellectomy, the quadriceps and patellar tendons are sewn together end-to-end, recreating a continuous connection so you can still straighten your knee. The repair may be reinforced with additional materials to provide extra stability during healing.
How It Affects Knee Strength and Movement
The kneecap increases the mechanical advantage of your thigh muscle by about 30 to 50 percent. Losing it means your quadriceps has to work considerably harder to produce the same force, and in practice, it can’t fully compensate.
Research on patients after patellectomy found that even those with the best outcomes experienced a 45% loss of quadriceps power compared to their unaffected leg. Patients with less favorable results saw a 60% loss. That’s a meaningful reduction that affects everyday activities like climbing stairs, rising from a chair, and walking on uneven ground.
Total patellectomy causes more problems than partial removal across every measure. Patients who lose the entire kneecap have greater ligament instability, more muscle wasting in the thigh, and more pronounced weakness than those who keep part of it. Gait studies show that people without a kneecap bend their knee less during the stance phase of walking, both on flat surfaces and when going up or down stairs. This changes how they walk and can make movements feel less stable or controlled.
Recovery Timeline
Recovery from patellectomy follows the same general framework as other major tendon repairs around the knee, though individual timelines vary based on how much bone was removed and how well the repair holds.
For the first two weeks, the knee is kept in a locked brace held straight, and bending is limited to no more than 60 degrees. You can put weight on the leg with the brace locked in extension from the start, but crutches or a walker are needed for balance and protection. By six weeks, most patients are bearing full weight.
Knee bending progresses slowly, about 10 degrees per week during the first several weeks. The goal is to reach 90 degrees of flexion by week five, which is roughly the amount needed to sit comfortably in a chair. Between weeks six and fifteen, the brace is unlocked to allow movement during walking, and the focus shifts to restoring full range of motion. Weight-bearing activities with the knee bent past 90 degrees are typically restricted until after eight weeks to protect the repair.
By four to six months, most patients are working toward at least 120 degrees of flexion and rebuilding quadriceps strength and flexibility. Return to sport or physically demanding activities generally falls in the six-to-eight-month window, though many patients after total patellectomy find that high-impact activities remain permanently limited due to the loss of mechanical advantage in the knee.
Long-Term Outlook
Living without a kneecap is manageable, but it does change what your knee can do. Many people return to daily activities, walking, and light exercise. The biggest ongoing challenge is quadriceps weakness, which can make stairs and getting up from low surfaces more difficult than before surgery.
If knee arthritis develops later in life, having had a prior patellectomy doesn’t rule out knee replacement surgery. A meta-analysis of patients who underwent total knee replacement after a previous patellectomy found significant improvements in functional outcome scores, with high retention rates at mid-term follow-up. So while patellectomy changes the knee permanently, it doesn’t close the door on future treatment options if the joint continues to deteriorate.