Habitual dislocation of patella: A review

Abstract

Habitual dislocation of patella is a condition where the patella dislocates whenever the knee is flexed and spontaneously relocates with extension of the knee. It is also termed as obligatory dislocation as the patella dislocates completely with each flexion and extension cycle of the knee and the patient has no control over the patella dislocating as he or she moves the knee(1). It usually presents after the child starts to walk, and is often well tolerated in children, if it is not painful. However it may present in childhood with dysfunction and instability. Very little literature is available on habitual dislocation of patella as most of the studies have combined cases of recurrent dislocation with habitual dislocation. Many different surgical techniques have been described in the literature for the treatment of habitual dislocation of patella. No single procedure is fully effective in the surgical treatment of habitual dislocation of patella and a combination of procedures is recommended.

Tibial Tubercle Proximalization: A Novel Technique to Lengthen the Extensor Mechanism in Skeletally Mature Patients With Lateral Habitual Patellar Dislocations

“…The typical clinical presentation of an HPD in young children is an odd-looking knee and, less often, pain and instability. 2 Contracture and fibrosis of the quadriceps muscle, mainly the vastus lateralis, 1 and iliotibial band contracture 11 may give rise to HPDs. In this study, all of the included patients developed HPDs as children, presenting many years after their initial instability event.…”

“…Further flexion is then possible only if the patella is allowed to dislocate, when a full range of motion (ROM) is readily obtainable. 1 – 3 …”

“…Further flexion is then possible only if the patella is allowed to dislocate, when a full range of motion (ROM) is readily obtainable. [1][2][3] Various pathological factors have been described in the pathogenesis of HPDs, such as femoral trochlear dysplasia, increase in the Q angle, increase in the tibial tubercletrochlear groove (TT-TG) distance, lateral soft tissue contracture, and medial soft tissue relaxation. 7 Jeffreys 8 in 1963 described an abnormal attachment of the iliotibial tract to the patella, producing HPDs in knee flexion.…”

Extensive Lateral Release and Medial Patellofemoral Ligament Reconstruction in 25 Years of Chronic Fixed Lateral Patellar Dislocation: A 5-Year Follow-Up Case Report

“…It could be divided into acute and chronic patellar dislocation. Chronic patellar dislocation could be found in many types of manifestations and must be differentiated with the habitual and obligatory patellar dislocation, which was also chronically manifested [14]. As the patella is constantly dislocated, the patella could not enter the trochlear groove, eventually causing pain, apprehension, and loss of function [15].…”

Diagnosis and Management of Traumatic Patellar Instability in the Pediatric Patient

“…This may be a sign of habitual dislocation (ie, spontaneously dislocates with flexion and reduces with extension). 29,30 The Q angle is the angle formed by a line drawn from the anterior superior iliac spine to the central aspect of the patella and a second line drawn from the central aspect of the patella to the TT. Normal values are 14° for males and 17° for females.…”