The patella, commonly known as the kneecap, is a small bone that sits within the quadriceps tendon at the front of the knee. It is designed to glide smoothly within a specialized groove on the end of the thigh bone, called the trochlear groove. Patellar maltracking occurs when the kneecap does not follow this natural path, instead shifting or tilting incorrectly within the groove. This misalignment is a common orthopedic issue that can lead to irritation and discomfort in the knee joint.
Understanding Patellar Maltracking
Patellar maltracking is often associated with patellofemoral pain syndrome. It describes a mechanism where the kneecap is pulled slightly out of alignment, typically moving laterally or outward, instead of gliding smoothly inside the trochlear groove of the femur. This abnormal movement causes increased friction and pressure on the cartilage surfaces of the patella and the femur. The resulting irritation leads to pain and discomfort located at the front of the knee.
Patients often experience a dull, aching pain around or under the kneecap, which worsens with activities that involve bending the knee under load. This includes walking up or down stairs and hills, squatting, or running. Another common complaint is the “theater sign,” which is pain after prolonged sitting with the knees bent. Sensations of clicking, grinding, or popping (crepitus) may also occur. In more significant cases, people may feel a sense of instability, or that the knee is prone to “giving way” or buckling.
Root Causes of Misalignment
The primary factors contributing to patellar maltracking are related to biomechanical imbalances and anatomical variations within the leg. A significant cause involves an imbalance in the quadriceps muscle group. Specifically, the vastus lateralis muscle on the outer thigh may exert a stronger pull than the vastus medialis obliquus (VMO) on the inner thigh. When the VMO is weak or has a delayed activation, it fails to counteract the outward pull, allowing the patella to track laterally.
Anatomical features can also predispose an individual to maltracking by increasing the lateral forces on the kneecap. One factor is an increased Q-angle, which measures the angle of pull of the quadriceps muscle relative to the patellar tendon. A larger Q-angle can result from structural issues like knock-knees or foot pronation, increasing the outward force on the patella. The shape of the trochlear groove itself also plays a role; a groove that is too shallow (trochlear dysplasia) provides less bony restraint to keep the kneecap centered.
Soft tissue tightness on the outer side of the knee is a major contributor to misalignment. A tight lateral retinaculum, connective tissue on the outside of the kneecap, can chronically tether and tilt the patella laterally. Tightness in the iliotibial band (IT band) can also increase this outward pull, overwhelming the medial stabilizing structures. This combination creates an environment where the patella is constantly being pulled away from its correct central path.
Diagnosis and Non-Surgical Management
Diagnosis of patellar maltracking begins with a thorough physical examination, where a clinician will observe the patient’s gait and perform specific tests to assess patellar mobility and tracking. Palpation around the kneecap can help identify areas of tenderness and determine the degree of tilt or shift. A common maneuver is the patellar apprehension test, where the examiner gently attempts to push the patella laterally, and a positive result is indicated by the patient guarding or showing fear of dislocation.
Imaging techniques are used to confirm structural causes and rule out associated damage. X-rays can measure bony alignment, including the Q-angle, and identify conditions like patella alta, where the kneecap sits too high. An MRI may be ordered to visualize soft tissues, such as the articular cartilage, to assess for wear or fraying (chondromalacia). It also checks for damage to stabilizing ligaments like the medial patellofemoral ligament (MPFL).
Conservative treatment is the primary approach for patellar maltracking. Physical therapy is a core component, focusing on strengthening the VMO to improve its ability to pull the patella medially. Exercises target the hip and core muscles, such as the gluteus maximus, since weakness in these areas contributes to poor lower extremity biomechanics. Stretching tight structures, including the hamstrings, hip flexors, and the IT band, is part of the rehabilitation program.
Patellar taping, such as the McConnell technique, is a common non-surgical adjunct that can provide immediate pain relief. This method uses non-elastic tape to manually shift the patella into a more medial and aligned position within the groove. By reducing pain, the taping allows patients to perform their strengthening exercises more effectively and without discomfort. Bracing or orthotics may also be recommended to provide external support and correct foot mechanics, helping to reduce the forces that encourage lateral tracking.
Surgical Interventions and Recovery
Surgery is reserved for cases of severe maltracking or instability, particularly when conservative treatments have failed to provide relief after six months or more. The goal of surgical intervention is to realign the path of the patella and restore stability to the joint. One common procedure is a lateral release, where the tight lateral retinaculum is cut to reduce the outward pull and tension on the kneecap. This is often performed arthroscopically, involving small incisions.
For more significant anatomical issues, a procedure called tibial tubercle transfer may be necessary. This involves cutting the tibial tubercle, the bony prominence on the shinbone (tibia) where the patellar tendon attaches, and moving it to a new, more medial position. This adjustment effectively changes the angle of pull of the entire quadriceps mechanism, providing a mechanical correction to the alignment. The repositioned bone fragment is then secured with screws.
Recovery from surgical correction requires a structured post-operative rehabilitation program. Initially, the focus is on protecting the surgical site, managing pain, and restoring a controlled range of motion. Patients may use a brace or immobilizer in the early stages until they can demonstrate control of the leg muscles. Intensive physical therapy follows, emphasizing strengthening the entire leg and core. Full return to sports or demanding activities can take several months, as the bone and soft tissues require time to heal and adapt to the new alignment.