Application of Three-Dimensional Computed Tomography Improved the Interrater Reliability of the AO/OTA Classification Decision in a Patellar Fracture.

Seong-Eun Byun,Wonchul Choi,Oog-Jin Shon,Yong-Bum Joo,Young-Gon Na,Jae-Ang Sim,Ji-Wan Kim

doi:10.3390/jcm10153256

Abstract

We investigated whether interrater reliabilities of the AO/OTA classification of patellar fracture change with the imaging modalities applied, including plain radiography and two- and three-dimensional (2-D and 3-D) computed tomography (CT). Seven orthopedic specialists and four orthopedic residents completed a survey of 50 patellar fractures to classify the fractures according to the AO/OTA classification for patellar fractures. Initially, the survey was conducted using plain radiography only, then with 2-D CT introduced three weeks later and 3-D CT introduced six weeks later. Fleiss’ Kappa coefficients were calculated to determine interrater reliability. The overall interrater reliability of the AO/OTA classifications was 0.40 (95% CI, 0.38–0.42) with plain radiography only and 0.43 (95% CI, 0.41–0.45) with the addition of 2-D CT. With the addition of 3-D CT, the reliability was significantly improved to 0.54 (95% CI, 0.52–0.56). In specialists, interrater reliability of the classifications was moderate with all three imaging modalities. With the use of 3-D CT, interrater reliability of the classification was 0.53 (95% CI, 0.50–0.56), which was significantly higher than that with the use of 2-D CT (κ = 0.45; 95% CI, 0.42–0.48). In residents, interrater reliability of the classification was 0.30 (95% CI, 0.24–0.36) with plain radiography. The reliability improved to 0.49 (95% CI, 0.43–0.56) with the addition of 2-D CT, which was significantly higher than that with plain radiography only. The use of 3-D CT imaging improved interrater reliability of the classification. Therefore, surgeons, especially residents, may benefit from using 3-D CT imaging for classifying and planning the treatment of patellar fractures.

Highlights

The patella functions as a lever for the extensor mechanism of the knee joint, and it constitutes the patellofemoral joint with three-quarters of the posterior aspect covered by articular cartilage [1]
The overall interrater reliability of the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification was fair (κ = 0.40; 95% confidence interval [CI], 0.38–0.42) with plain radiography only, and moderate (κ = 0.43; 95% CI, 0.41–0.45) with the addition of 2-D computed tomography (CT)
With the addition of 3-D CT, interrater reliability of the AO/OTA classification was 0.54, which was significantly higher than that of other modalities (Figure 2)

Summary

Introduction

The patella functions as a lever for the extensor mechanism of the knee joint, and it constitutes the patellofemoral joint with three-quarters of the posterior aspect covered by articular cartilage [1]. More than 80% of patellar fractures are intraarticular fractures [2,3], and complications such as joint stiffness and postoperative arthritis can occur [4]. Anatomic reduction of the articular surface and rigid fixation are the treatment goals to prevent such complications. For anatomic reduction and selection of the appropriate fixation method, precise evaluation and in-depth understanding of the fracture patterns are essential. The classification of the fractures plays an important role in the evaluation. The Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification has been used and was recently revised [5]. The interrater reliability of the AO/OTA classification of patellar fractures were found to be only fair among trauma specialists, even with the use of two-dimensional (2-D) computed tomography (CT) [6]

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Conclusion