Patella instability in children and adolescents

Abstract

Patellar instabilities are the most common knee pathologies during growth. Congenital dislocations are rare. Extensive, early soft tissue releases relocate the extensor mechanism and may enable normal development of the femoro-patellar anatomy.Conservative management is the preferred strategy after a ‘first-time’ traumatic dislocation. In cases with concomitant anatomical predisposing factors such as trochlear dysplasia, malalignment, malrotation or ligamentous laxity, surgical reconstruction must be considered. The same applies to recurrent dislocations with pain, a sense of instability or re-dislocations which may also lead to functional compensatory mechanisms (quadriceps-avoiding gait in knee extension) or cartilaginous lesions with subsequent patello-femoral osteoarthritis. The decision-making process guiding surgical re-alignment includes analysis with standard radiographs and MRI of the trochlear groove, joint cartilage and medial patello-femoral ligament (MPFL). Careful evaluation of dynamic and static stabilisers is essential: the medial patello-femoral ligament provides stability during the first 20° of flexion, and the trochlear groove thereafter.Excessive femoral anteversion, general ligamentous laxity with increased femoro-tibial rotation, patella alta and increased distance between the tibial tuberosity and the trochlear groove must also be taken into account and surgically corrected.In cases with ongoing dislocations during skeletal immaturity, soft tissue procedures must suffice: reconstruction of the medial patello-femoral ligament as a standalone procedure or in conjuction with more complex distal realignment of the quadriceps mechanism may lead to a permanent stable result, or at least buys time until a definitive bony procedure is performed.Cite this article: Hasler CC, Studer D. Patella instability in children and adolescents. EFORT Open Rev 2016;1:160-166. DOI: 10.1302/2058-5241.1.000018.

Development of an innovative measurement method for patellar tracking disorder

“…If patellar maltracking was present in individuals from childhood, but it was not corrected in a timely manner, there would be an increase in patellofemoral joint pressure, potentially causing the cartilage injury and femoral trochlear severe deformity to progress. This could lead to an increased risk of long-term adverse outcomes and accelerate the rate of the patellofemoral joint osteoarthritis [ 28 – 30 ] as an adult. Studies have shown that the incidence of patellofemoral osteoarthritis within 15 years of patellar maltracking detection was as high as 50%, even after the initial patellar dislocation was corrected by surgery.…”

Medial Patellofemoral Ligament Reconstruction and Nonanatomic Stabilization Techniques in Skeletally Immature Patients

“…However, counseling regarding second-stage definitive surgery after the end of growth is mandatory. 48 Further studies are required to identify the most reliable surgical techniques in these challenging cases.…”

Isolated Avulsion Fracture of Patellar Attachment of Medial Patellotibial and Medial Patellomeniscal Ligaments in the Presence of Trochlear Dysplasia: An Indication for Acute Surgical Repair

“…Several anatomic structures stabilize the patella throughout knee motion. These structures are classified as dynamic (vastus medialis), passive (ligaments: medial and lateral restraints) and static (osseous anatomy: patella, trochlea, tibial tubercle) [1,2,6]. Medial restraints are the main passive stabilizers against lateral patellar dislocation and are further classified as proximal [medial quadriceps tendon femoral ligament (MQTFL), MPFL], and distal (MPTL, MPML) [1,2].…”