Predictive Scoring for Recurrent Patellar Instability After a First-time Patellar Dislocation

Abstract

Purpose: Patellofemoral instability is a common acute knee injury seen in the pediatric population. First-time patellar dislocations usually undergo conservative management, but ~15% to 80% of patients experience recurrent instability. This study aims to develop a prediction model using radiographic parameters of the patellofemoral joint seen on computed tomography scans in different degrees of knee flexion, to determine the risk of recurrence after the first episode of patellofemoral instability. Methods: A 12-year retrospective case-control study was performed. All patients in a single institution aged 18 years or younger who had a computed tomography patellar tracking scan performed for patellar instability were included. Predictors included in the score were determined through backward logistic regression and compared using receiver operating characteristic curve analysis. Results: This study revealed that recurrent dislocation in first-time patellofemoral dislocation could be accurately predicted using the prediction score that consisted of age, tibial tubercle-trochlear groove distance and congruence angle at 10- and 20-degree flexion. The sensitivity of the score was 100% and specificity was 73.3%. Three diagnostic zones were identified and used to categorize patients into low-, intermediate-, and high-probability groups. Conclusion: This study presented a scoring system that incorporated radiographic knee kinematics in the risk assessment for recurrent patellofemoral instability for patient stratification. The scoring system could guide the decision for early surgical intervention after the first-episode patellofemoral dislocation for patients at high risk of recurrent patellofemoral dislocation.

Children’s orthopaedics

“…This study from Singapore therefore aimed to develop a predictive model for recurrence. 8 The authors took an innovative approach and attempted to establish a 3D tracking score based on radiological parameters of the patellofemoral joint taken in different degrees of knee flexion as they appear on CT scans. Over a period of 12 years, they retrospectively reviewed all patients undergoing a CT scan for patellar instability in their single centre.…”

“…We would note that MRI in two-year-olds is challenging with anaesthetic or sedation generally required, so practically it is less likely to be a routine investigation for all hips, but it may have use in predicting outcomes and the requirement for selected cases where early intervention might be required.Patellar dislocations are common in adolescents, and first-time dislocations are most commonly treated with nonoperative management, although between 15% and 80% of patients experience recurrent instability. This study from Singapore therefore aimed to develop a predictive model for recurrence 8. The authors tookResearchX-ref For other round ups in this issue that cross-reference with Research see: Hip & Pelvis round ups 2 & 5; Oncology round up 1; Shoulder & Elbow round up 4; Trauma round up 2.Clinical and epidemiological features of scaphoid fracture nonunion X-refA retrospective study from Beijing (China) has described the characteristics of a large consecutive series of patients al presenting with scaphoid nonunions over an 11-year period 1.…”