"Does advanced imaging improve the reliability of 2018 AO/OTA classification for trochanteric femoral fractures?".

BACKGROUND

The influence of advanced imaging modalities on the reliability of 2018 AO/OTA classification and detection of features contributing to fracture instability have not been adequately studied in the literature.

METHODS

This prospective study was conducted to assess the reliability of 2018 AO/OTA classification for trochanteric femoral fractures, and features of instability in 50 patients using radiographs, multiplanar reformats (MPR), and 3D-reconstruction with fracture segmentation (3DR-FS) by 3 observers on 2 occasions at an interval of 4 weeks.

RESULTS

Mean inter-observer reliabilities on radiographs, MPR, 3DR-FS were 0.36, 0.39, 0.46 after first reading, and 0.35, 0.35, 0.44 after second reading respectively. The mean intra-observer reliabilities for radiographs, MPR, 3DR-FS were 0.36, 0.43, and 0.50 respectively. Inter-observer reliabilities on subgroup analysis were 0.35, 0.27, 0.40 for subgroup A1 and 0.19, 0.22, and 0.30 for subgroup A2 on radiographs, MPR and 3DR-FS respectively. All results were statistically significant (p-value <0.05). Posterior comminution was detected in 125(41 %), 247(82 %), and 255 (85 %) out of total 300 instances on radiographs, MPR and 3DR-FS respectively. Coronal split was detected in 113(37 %), 189(63 %), and 242 (80 %) out of total 300 instances on radiographs, MPR, and 3DR-FS respectively. Flexion of the proximal fragment was detected in 106(35 %), 163(54 %), and 180 (60 %) out of total 300 instances on radiographs, MPR, and 3DR-FS respectively. Lateral wall fracture was detected in 45(15 %), 80(26 %), and 138 (46 %) out of total 300 instances on radiographs, MPR, and 3DR-FS respectively. The banana fragment was detected in 5(1 %), 16(5 %), and 83 (27 %) out of a total of 300 instances on radiographs, MPR, and 3DR-FS respectively.

CONCLUSIONS

2018 AO/OTA classification for trochanteric femoral fractures has 'fair' reliabilities on radiographs and MPR that improve to 'moderate' on adding 3DR-FS. We attribute it mostly to the difficulty in localizing innominate tubercle. Adding advanced imaging helps better detect fracture instabilities.

LEVEL OF EVIDENCE: Level I, Diagnostic.