Patellar Instability With and Without Trochlear Dysplasia: New Arthroscopic Medial Soft Tissue Plication With Pullout Technique

Abstract

The aim of this study was to analyze clinical and radiologic results of an arthroscopic medial plication with the pullout technique and to define indications and limitations of this procedure for patellar instability. Records of 45 patients treated for patellar instability with arthroscopic medial plication with the pullout technique were reviewed. The mean patient age was 22.8±8.3 years. The tibial tuberosity-trochlear groove distance, trochlear depth (TD), and Insall-Salvati ratio were measured using magnetic resonance imaging taken preoperatively. Patients were evaluated clinically by the Insall and Kujala score and radiographically by measuring the congruence angle, lateral patellofemoral angle, and lateral patellar translation pre- and postoperatively. Patients were classified into 2 groups: group 1 comprised 23 patients with TD greater than or equal to 3.0 mm and group 2 comprised 22 patients with TD less than 3.0 mm. A significant improvement (P=.007) in postoperative clinical scores compared with preoperative values was observed. The congruence angle improved to 11.0°±20.6° (P=.006), the lateral patellofemoral angle improved to -1.6°±7.7° (P≤.0001), and the lateral patellar translation improved to 8.7±5.3 mm (P≤.0001) postoperatively. There were 5 (11%) failure cases. No significant difference existed in the number of failure cases and clinical scores between the 2 groups. This arthroscopic medial soft tissue pullout technique showed good clinical and radiologic results for patellar instability even in the presence of mild to moderate trochlear dysplasia. However, the technique showed limited success in severe trochlear dysplasia cases.

Quality-of-Life Outcomes of Patients following Patellofemoral Stabilization Surgery: The Influence of Trochlear Dysplasia

“…This is consistent with other literature on the success rate of MPFL-I. 22,23 Interestingly, there were more patients with highgrade dysplasia in the MPFL-R group. This between-groups difference likely represents purposeful selection bias in the à la carte surgical approach, whereby patients with more pathoanatomic risk factors such as trochlear dysplasia are selected to receive a more robust procedure.…”

“…The main finding in this study was a statistically significant correlation between measures of trochlear dysplasia and QOL physical symptoms scores, an average of 2 years following patellofemoral stabilization surgery. This statistically significant finding aligns with previous research that demonstrated poorer clinical outcomes for MPFL imbrication 22,23 and MPFL reconstruction 18,19,21,31 in patients with high-grade trochlear dysplasia. This study used a disease-specific patient-reported outcome measure as an assessment tool, and therefore provided further evidence that trochlear dysplasia is a predictor of surgical outcome in patients with patellofemoral instability.…”

“…The measurements of the lateral radiographs were performed as described by Dejour and Le Coultre 1 which has previously been established as a reliable method. 22,30 The degree of trochlear dysplasia (no, low-grade, high-grade), the presence or absence of a crossing sign, the presence of a trochlear bump, and the height of the trochlear bump, if present, were assessed and documented.…”

“…[12][13][14][15][16][17] Trochlear dysplasia has also been implicated as a significant risk for the failure of stabilization procedures such as reconstruction [18][19][20][21] and imbrication of medial patellofemoral ligament (MPFL). 22,23 A systematic review of the indications for MPFL reconstruction noted that trochlear dysplasia was the second most common reason cited in studies for not performing an isolated MPFL reconstruction. 24 In addition, correcting high-grade trochlear dysplasia with a trochleoplasty procedure results in improved outcomes compared with an isolated patellofemoral stabilization.…”

Tibial Tubercle Osteotomy and Medial Patellofemoral Ligament Imbrication for Patellar Instability Due to Trochlear Dysplasia

“…However, other studies have demonstrated an increased rate of redislocation after MPFL reconstruction or imbrication alone in the setting of trochlear dysplasia. 1,16,24…”