Patellar Instability Surgical Treatment

Surgical treatment for patellar instability is typically considered when:

• Nonoperative treatment has failed: Physical therapy and bracing have not provided adequate stability or relief.
• Recurrent dislocations are occurring: The kneecap continues to slip despite nonoperative management.
• A loose fragment is present: A dislocation has broken off a piece of cartilage or bone that should be repaired or removed.
• High-risk anatomy is identified in the first time dislocator: Each dislocation can injure the joint surface, and early treatment protects against long-term cartilage damage, which ultimately leads to arthritis.

Dr. Rynecki Baker pays particular attention to high-risk patients. In patients who are still growing and also have trochlear dysplasia, a high-riding kneecap, and a history of dislocation in the opposite knee, the risk of another dislocation without surgery can approach 88%.

The MPFL is the primary restraint against outward displacement of the kneecap. It is almost always torn with a kneecap dislocation. Dr. Rynecki Baker reconstructs it using a tendon graft, restoring the tether that holds the kneecap in place. Precise positioning of the graft and careful tensioning are critical to restoring stability without over-constraining the kneecap. MPFL reconstruction is the most common surgical treatment for patellar instability and is highly reliable in appropriately selected patients. In patients who are still growing, the reconstruction can be performed using techniques that avoid the growth plates. Dr. Rynecki Baker’s published research has contributed to the evidence guiding patient selection and long-term expectations after MPFL reconstruction.

When bony malalignment, such as an elevated TT-TG distance or a high-riding kneecap (patella alta), contributes to instability, Dr. Rynecki Baker may recommend a tibial tubercle osteotomy. The bony attachment of the patellar tendon is cut, repositioned, and secured with screws. Moving it toward the inside of the knee reduces the outward pull on the kneecap, and moving it downward seats a high-riding kneecap in the groove earlier during knee bending. TTO is often performed alongside MPFL reconstruction in patients with significant anatomic risk factors, and it can also shift load away from damaged areas of cartilage.

In cases of severe trochlear dysplasia, where the groove is too flat to provide meaningful bony support or a “speed bump” at its entrance prevents the kneecap from entering the groove, Dr. Rynecki Baker may address the groove itself. Trochleoplasty deepens and reshapes the trochlear groove to create a more stable track for the kneecap. It is typically combined with MPFL reconstruction and is reserved for selected patients with the most significant bony abnormalities.

In some patients, the underlying cause of instability is the angle or rotation of the thigh bone. When you are bow-legged, this is called valgus, and when there is too much rotation, this is a condition called excessive femoral anteversion. When this malalignment contributes to recurrent dislocation, Dr. Rynecki Baker may recommend a femoral osteotomy, in which she cuts the thigh bone is cut. The angle of the bone can be changed by either elevating the bone or removing a piece of bone. Similarly, it can also be rotated to the correct position if this is the source of the problem. It is either secured with a plate or rod depending on which procedure was performed. By correcting the alignment at its source, osteotomy addresses the root cause of instability rather than compensating for it.

Surgery for patellar instability often includes treatment of associated injuries:

• Knee arthroscopy: A camera inserted through small incisions allows Dr. Rynecki Baker to examine the cartilage, assess how the kneecap tracks, and remove loose fragments.
• Fragment fixation: When a dislocation breaks off a sizable piece of cartilage and bone, it can often be fixed back in place, ideally soon after the injury.
• Cartilage procedures: If cartilage damage is identified, Dr. Rynecki Baker addresses it at the same time, as untreated defects can contribute to long-term pain and arthritis.
• Lateral retinacular lengthening: When the tissues on the outer side of the kneecap are excessively tight, they may be lengthened to allow the kneecap to sit centrally in the groove.

Recovery from surgery for patellar instability is gradual and requires commitment to a structured rehabilitation program. Weightbearing, bracing, and crutch use depend on the procedures performed, with bony procedures such as TTO, trochleoplasty, and osteotomy requiring additional protection while the bone heals. Physical therapy begins early, focused on restoring range of motion, rebuilding quadriceps and hip strength, and retraining movement patterns.

Return to sport after MPFL reconstruction typically occurs around six months, and often later when an osteotomy or trochleoplasty is performed. Progression is guided by motion, strength, and movement quality rather than the calendar alone. Dr. Rynecki Baker works closely with each patient and their physical therapist throughout recovery, and every patient receives individualized guidance at each stage, with the goal of returning to sport or full activity safely and confidently.