Inter and Intra-Observer Reliability of Dorr Classification in Proximal Femur Morphology

Abstract

Background: Proximal femur morphology determines the choice of cemented or uncemented Total Hip Arthroplasty (THR), and Dorr classification is widely used to type this characteristic. As a result, a considerable reliability for such typing system is expected. Objectives: The current study aimed at assessing inter and intra-observer reliability of Dorr classification in proximal femur morphology. Methods: A total of 50 standard hip radiographs from patients with trauma or THR candidates were evaluated by 6 observers, including 2 senior orthopedic residents, 2 orthopedic surgeons, and 2 hip fellowship-trained orthopedic surgeons, using the Dorr classification system. Subsequently, radiographs were re-numbered and re-evaluated, 6 weeks after the first review. Cohen's Kappa statistic was used for statistical analysis of inter and intra-observer reliability. Results: The mean intra-observer and inter-observer kappa value for the residents was 0.560 and 0.592, respectively. The mean intra-observer and inter-observer kappa value for the orthopedists was 0.566 and 0.540, respectively. The mean intra-observer and inter-observer kappa value for the hip fellowships was 0.477 and 0.490, respectively. Conclusions: A minimum to moderate inter and intra-observer reliability of Dorr classification system was seen between the observers of the current study. These results suggest that the classification of the femur morphology is more challenging than previously described and characterization of a single Dorr type, especially in case of uncertainty between type B and C of Dorr might need reconsideration, in order to prevent its adverse effect on the patients' outcome.

Influence of bone morphology and femur preparation method on the primary stability of hip revision stems

“…Since CT scans are recommended before revisions, the patient would not be exposed to additional radiation. 39 The semi-automatic, numerical determination of femoral morphology, additionally improves the inter-and intraobserver reliability deplored in literature 29,30 Standard powered reaming appears to be superior compared to the manual approach since it is time-efficient, involves less physical work and yields to higher torsional strength, presumably due to a more uniform cavity. It is uncertain whether straight reamers further improve the junction due to their changed geometry or merely due to the sharper cutting edges caused by the less previous operating time of the reamer.…”

“…Since CT scans are recommended before revisions, the patient would not be exposed to additional radiation 39 . The semi‐automatic, numerical determination of femoral morphology, additionally improves the inter‐ and intraobserver reliability deplored in literature 29,30 and could be implemented fully automatically in modern preoperative planning software. The negative correlation between CCR and CI was already mentioned by Dorr et al but not pursued further 26 .…”

“…Furthermore, using the CCR or the CI does not necessarily yield the same Dorr type for a specific femur, which makes a unique classification impossible in some cases. Combined, this can lead to ambiguous results even for the most experienced surgeons 29,30 . A unique classification to evaluate the morphology of the proximal femur based on the original work of Dorr is desirable to support surgeons' implant choices and to elucidate differences in clinical outcomes.…”

“…Combined, this can lead to ambiguous results even for the most experienced surgeons. 29,30 A unique classification to evaluate the morphology of the proximal femur based on the original work of Dorr is desirable to support surgeons' implant choices and to elucidate differences in clinical outcomes.…”

Evaluation of the Relationship between Osteoporosis Parameters in Plain Hip Radiography and DXA Results in 156 Patients at a Single Center in Turkey

“…Mazhar et al performed a DI reliability analysis and stated that this resulted in moderate intra-observer and inter-observer agreements and stated that more reliable characterization systems are needed to classify femoral morphology [17]. In another study, inter-examiner reproducibility was found to be κ = 0.32 (fair agreement) in the inexperienced group and κ = 0.52 (moderate agreement) in the experienced group [18].…”