Anterior knee pain due to recurrent patellar instability is one of the most common entities seen in a sports medicine practice.
Anterior knee pain due to recurrent patellar instability is one of the most common entities seen in a sports medicine practice. In the 17 year old population, the incidence of patellar instability is 29 cases per 100,000. These injuries will typically occur when the leg internally rotates with a fixed foot with simultaneous quadriceps contraction.
The challenge in treating patellar instability is that the rate of subsequent patellar dislocation increases after the first episode. These dislocations can also cause patellofemoral cartilage damage, osteochondral fracture, pain, and development of patellofemoral arthritis. Case A 17 year old female comes to your office after a first time patella dislocation.
An MRI was done by her Pediatrician who found a 5mm osteochondral defect and loose body along the lateral femoral condyle. What is first line treatment? A) Physical therapy for 6 weeks B) Referral to Orthopedic Surgery C) MRI with contrast to evaluate the osteochondral defect D) RICE for 4 weeks and then closed chain exercises Diagnosis Patella stability relies on the patella, femoral trochlea, medial-patella femoral ligament, quadricep muscle, and limb alignment.
Radiographic imaging with both lateral and Merchant views help assess for patella instability. A Merchant view allows for assessment of patella tilt and trochlear dysplasia. It is also important to assess the Q angle, which is the angle between the lines of action of the patella and the quad tendon.
An increased Q angle causes a lateral directed vector on the patella and can lead to patella instability. Another marker of MPFL alteration is the tibial tubercle lateralization (TT-TG) with an abnormal TT-TG being reported as >25 mm. The TT-TG distance suggests lateralization of the tibia tubercle compared to the trochlear groove.
If you are experiencing symptoms that may be related to recurrent patellar instability, it is important to see a sports medicine physician. Early evaluation and treatment typically lead to better outcomes. Do not ignore pain or symptoms that are limiting your activity.
*This article is for educational purposes only and does not substitute for professional medical advice. Always consult a qualified healthcare provider.*
Connect with a doctor, physical therapist, or imaging center near you.
Find a Provider Near You โ