Elsevier

Injury

Volume 36, Issue 7, July 2005, Pages 858-861
Injury

Reliability of classification systems for intertrochanteric fractures of the proximal femur in experienced orthopaedic surgeons

https://doi.org/10.1016/j.injury.2005.02.005Get rights and content

Summary

Introduction:

The aim of this study was to determine the reliability of currently used classification systems for intertrochanteric fractures of the proximal femur, and to determine the reliability of these systems in experienced orthopaedic surgeons.

Materials and methods:

Forty intertrochanteric fractures of the proximal femur were classified independently by five experienced observers using the AO, Evans, Kyle, and Boyd classification systems on two separate occasions 3 months apart. The interobserver and intraobserver variation was assessed using kappa statistics.

Results:

The level of agreement for classification into AO groups was almost perfect or substantial, and higher than other classification systems. When the fractures were further classified using the AO classification with subgroups, reliability became worse.

Conclusions:

The current study suggests that the AO classification system with groups can be used more reliably to measure intertrochanteric fractures of the proximal femur than Evans, Kyle, and Boyd classification systems. However, the reliability of the AO classification with subgroups is not satisfactory.

Introduction

There are several classification systems for intertrochanteric fractures of the proximal femur, which have been widely used in clinical practice. Evans8 developed a classification system based on the direction of the fracture line and the assessment of stability on the likelihood of fracture reduction and redisplacement. Thereafter, Boyd and Griffith2 and Kyle et al.11 described their classifications. In 1990, the AO classification system13 was introduced. These classification systems have been used for planning treatment and predicting the outcome.

Any ideal classification system must be reliable5. Studies have assessed the reliability of the AO and Evans classifications1, 9, 14, 15. These studies show that the AO (group) classification is reliable, but the AO (subgroup) and Evans classification systems have poor agreement. The observers participating in these studies were not usually fully trained specialists. This may explain the unacceptably low levels of reliability demonstrated in these studies. Specialists have been shown to have a higher reliability than non-specialists for some classification systems6, 7, 16.

The aim of this study was to determine the reliability of currently used classification systems for intertrochanteric fractures of the proximal femur, and to determine whether they have an acceptable reliability when applied by experienced orthopaedic surgeons.

Section snippets

Materials and methods

We included all patients treated for intertrochanteric fractures of the proximal femur in our hospital between January and March 2003. We excluded patients whose radiographs were of inadequate quality, leaving a total of 40 patients. Plain anteroposterior and lateral radiographs were available for all cases.

These radiographs were reviewed by five orthopaedic surgeons who each had more than 10 years experience in orthopaedic trauma. Each observer was given a brief introduction and shown the

Results

The results of interobserver and intraobserver agreement were summarised in Table 1, Table 2, Table 3.

For the classification with AO groups, the mean kappa value of interobserver agreement was 0.80 (range, 0.62–0.91) in the first classification session and 0.75 (range, 0.62–0.91) in the second session. The mean kappa value for intraobserver agreement between the two sessions was 0.82 (range, 0.69–0.90). When the fractures were classified with AO subgroups, the mean kappa value of interobserver

Discussion

Our study demonstrated almost perfect or substantial interobserver and intraobserver agreement for the AO groups. In contrast, poorer interobserver and intraobserver agreement was found with the remaining three systems. Only a few studies have addressed the reliability of classification systems for intertrochanteric fractures of the proximal femur. Andersen et al.1 examined the reliability of Evans classification of trochanteric femoral fractures. Their kappa values showed moderate agreement

References (16)

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