Coronal and Transverse Malalignment in Pediatric Patellofemoral Instability

Abstract

Patellofemoral instability (PFI) encompasses symptomatic patellar instability, patella subluxations, and frank dislocations. Previous studies have estimated the incidence of acute patellar dislocation at 43 per 100,000 children younger than age 16 years. The medial patellofemoral ligament (MPFL) complex is a static soft tissue constraint that stabilizes the patellofemoral joint serving as a checkrein to prevent lateral displacement. The causes of PFI are multifactorial and not attributed solely to anatomic features within the knee joint proper. Specific anatomic features to consider include patella alta, increased tibial tubercle–trochlear groove distance, genu valgum, external tibial torsion, femoral anteversion, and ligamentous laxity. The purpose of this paper is to provide a review of the evaluation of PFI in the pediatric and adolescent patient with a specific focus on the contributions of coronal and transverse plane deformities. Moreover, a framework will be provided for the incorporation of bony procedures to address these issues.

Patellar Tendon Imbrication for the Treatment of Patella Alta in Skeletally Immature Patients

“…Patellar instability is a common pathology among adolescent patients, and the anatomical predisposition of patella alta can further play a role in frequent subluxation and dislocation events. [1][2][3] While tibial tubercle osteotomy has been used successfully for the correction of patellar height, [9][10][11] it can cause damage to the open physes of skeletally immature patients. In light of these limitations, soft-tissue procedures are better suited to treat this patient population, and may avoid the complications associated with tibial tubercle osteotomy such as nonunion, fracture, or hardware irritation.…”

“…Patella alta is a major contributor to recurrent patellar instability, which is commonly seen in young athletes. 1 , 2 This anatomical predisposition is characterized by an abnormally high-riding patella in relation to the tibia, femur, and trochlear groove and can interfere with proper joint kinematics and cartilage contact points. 3 , 4 Patella alta was found in 24% of patients with episodic patellar dislocation compared with only 3% in controls.…”

Alteration of patellar tendon morphology in patellofemoral instability (trochlear dysplasia)

“…5,6 It has yet to be ascertained whether TD is congenital or developmental. 5,7 Both osseous and dynamic soft tissue structures around the knee joint contribute to the stability of the PFJ at the knee joint. 8 Instability of the PFJ due to static abnormalities such as TD (trochlear morphology), patella Alta (higher position of patella), abnormal skeletal alignment due to genu valgum and/or torsion (excessive femoral anteversion or external tibial torsion) is well described in the literature.…”

Tibial Derotational Osteotomy for Patellofemoral Instability: A Systematic Review

“…Patellofemoral (PF) instability afects 23 in 100,000 personyears, with the majority of these cases occurring in young females [1]. Patellofemoral pain and instability can be caused by a variety of underlying conditions, including but not limited to insufcient medial patellofemoral ligament, patella alta, alignment deformity in the coronal plane, dysplastic trochlea, femoral torsional malalignment, or increased tibial tuberosity-trochlear groove distance (TTTG) [2][3][4][5][6][7]. Tibial torsion deformities have also been associated with patellofemoral (PF) pain and instability in the literature [8,9].…”