Validation of Lawrence and Botte classification of proximal fifth metatarsal fractures.

BACKGROUND

The Lawrence and Botte (LB) classification of proximal fifth metatarsal fractures guides clinical management, yet its reliability has been sparsely evaluated. This study investigated intra- and inter-rater reliability of the LB system among trained observers.

METHODS

A retrospective chart review identified patients with proximal fifth metatarsal fractures. Deidentified radiographs (AP, lateral, oblique) were reviewed by two orthopedic surgeons and one radiologist. Each observer classified fractures using the LB system in two surveys separated by at least two weeks. Identical radiographs were reordered between surveys to assess inter- and intra-rater reliability. Statistical analysis included Kruskal-Wallis, Friedman, weighted kappa, Cohen's kappa, and Fleiss' kappa.

RESULTS

200 patients were screened, and 85 radiographs included. Inter-rater reliability in Survey A showed no significant differences by Kruskal-Wallis; Friedman testing suggested minimal but significant variability. In Survey B, Kruskal-Wallis indicated significant differences in rankings. Weighted kappa coefficients for inter-rater reliability ranged 0.58-0.69 (moderate-substantial agreement). Intra-rater reliability ranged 0.61-0.82, with observer 2 highest (0.82). Cohen's kappa values were 0.58-0.71. Agreement between surveys (Fleiss' kappa) was 0.56, indicating moderate reliability.

CONCLUSION

The LB classification system demonstrates moderate inter-rater and substantial intra-rater reliability, though variability persists between raters and time points. While reasonably consistent, the findings highlight subjectivity in interpretation and suggest potential benefit in simplified schemes to improve agreement.