Plateau–patella angle: An option for the evaluation of patellar height in patients with patellar instability

• Published in: The knee Vol. 24; no. 2; pp. 340 - 344
• Main Authors: Bonadio, Marcelo Batista, Helito, Camilo Partezani, do Prado Torres, Julio Augusto, Gobbi, Riccardo Gomes, Pécora, José Ricardo, Camanho, Gilberto Luis, Demange, Marco Kawamura
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2017; Elsevier Limited
• Subjects: Adolescent; Adult; Body Weights and Measures; Child; Conflicts of interest; Dislocation; Female; Humans; Instability; Joint Instability - diagnostic imaging; Joint surgery; Knee; Male; Measurement; Methods; Middle Aged; Orthopedics; Patella; Patella - diagnostic imaging; Patellar dislocation; Patellar Dislocation - diagnostic imaging; Patellar height; Patients; Plateau–patella angle; Radiograph; Radiography; Recurrence; Retrospective Studies; Skin & tissue grafts; Tibia - diagnostic imaging; Young Adult; Young adults; Knee; Measurement; Radiograph; Patellar dislocation; Plateau–patella angle; Patellar height
• ISSN: 0968-0160; 1873-5800
• DOI: 10.1016/j.knee.2017.01.006

Abstract Background Patellar instability is a debilitating disease. An important factor related to recurrent dislocation is patellar height. A new method of patellar height measurement, the plateau–patella angle (PPA), was proposed in 2011. However, to date, there is no study evaluating the use of this method in patients with patellar instability. The aim of this study was to evaluate the PPA in patients with recurrent patellar dislocation. Methods This was a retrospective evaluation of the radiographs of 78 knees with patellar instability. Patellar height was measured using the Insall–Salvati (I/S), Caton–Deschamps (C/D) and Blackburne–Peel (B/P) indices and the PPA. The qualitative and quantitative correlations between the various methods and between observers were calculated. Results The PPA had a Pearson correlation of 0.76 ( P < 0.001) with the I/S index, 0.78 ( P < 0.001) with the C/D index and 0.90 ( P < 0.001) with the B/P index. In the qualitative correlation using the Spearman coefficient, the PPA had a correlation of 0.52 ( P < 0.001) with the I/S index, 0.72 ( P < 0.001) with the C/D index and 0.70 ( P < 0.001) with the B/P index. The correlations between the conventional methods were as follows: 0.57 ( P < 0.001) between the I/S and C/D indices; 0.61 ( P < 0.001) between the I/S and B/P indices; and 0.73 ( P < 0.001) between the C/D and B/P indices. Conclusion The determination of the PPA is a reproducible method that is consistent with the methods currently used to measure patellar height in patients with recurrent patellar dislocation.