A history of eponym usage in hip and pelvis radiography part 2: the adult hip

Eponyms, while inherently flawed, remain a constant in medical vernacular, especially in orthopaedic surgery. It is essential to understand how these eponyms came to be named and for whom they were named after in order to understand their correct usage and definitions. In this second part of a 2-part review, we describe the history of eponym usage in the radiography of the adult hip; who, when, what, where, and how. We hope to provide a historical perspective of interest, resolve any controversies in semantic definitions, and create a comprehensive library of eponymous terms related to adult hip radiography.

Determining the number of states in dynamic functional connectivity using cluster validity indexes

BACKGROUND

Clustering analysis is employed in brain dynamic functional connectivity (dFC) to cluster the data into a set of dynamic states. These states correspond to different patterns of functional connectivity that iterate through time. Although several cluster validity index (CVI) methods to determine the best clustering partition exists, the appropriateness of methods to apply in the case of dynamic connectivity analysis has not been determined.

NEW METHOD

Currently employed indexes do not provide a crisp answer on what is the best number of clusters. In addition, there is a lack of CVI testing in the context of dFC data. This work tests a comprehensive set of twenty four cluster validity indexes applied to addiction data and suggest the best ones for clustering dynamic functional connectivity.

RESULTS

Out of the twenty four considered CVIs, Davies-Bouldin and Ray-Turi were the most suitable methods to find the number of clusters in both simulation and real data. The solution for these two CVIs is to find a local minimum critical point, which can be automated using computational algorithms.

COMPARISON WITH EXISTING METHODS

Elbow-Criterion, Silhouette and GAP-Statistic methods have been widely used in dFC studies. These methods are included among the tested CVIs where the performances of all twenty four CVIs are compared.

CONCLUSIONS

Davies-Bouldin and Ray-Turi CVIs showed better performance among a group of twenty four CVIs in determining the number of clusters to use in dFC analysis.

The anatomical reduction of a moderate or severe stable slipped capital femoral epiphysis by modified Dunn subcapital osteotomy using the Ganz approach: functional and radiological outcomes

AIMS

This study analysed the clinical and radiological outcome of anatomical reduction of a moderate or severe stable slipped capital femoral epiphysis (SCFE) treated by subcapital osteotomy (a modified Dunn osteotomy) through the surgical approach described by Ganz.

PATIENTS AND METHODS

We prospectively studied 31 patients (32 hips; 16 females and five males; mean age 14.3 years) with SCFE. On the Southwick classification, ten were of moderate severity (head-shaft angle > 30° to 60°) and 22 were severe (head-shaft angle > 60°). Each underwent open reduction and internal fixation using an intracapsular osteotomy through the physeal growth plate after safe surgical hip dislocation. Unlike the conventional procedure, 25 hips did not need an osteotomy of the apophysis of the great trochanter and were managed using an extended retinacular posterior flap.

RESULTS

Clinical outcome was assessed using the range of movement and the Harris Hip (HHS), Western Ontario and McMaster Universities Osteoarthritis (WOMAC), and Merle d'Aubigné scores, while radiological measurements included slip and alpha angles. The mean duration of follow-up was 24.1 months (12 to 40). There was a significant improvement in all clinical and radiological measurements after treatment (p < 0.001). Post-operative major complications were one deep infection and one case of femoral head collapse.

CONCLUSION

These findings suggest that a modified Dunn osteotomy carried out through Ganz approach is a safe and effective method of treating the stable SCFE with a high degree of slip. Cite this article: Bone Joint J 2016;98-B:1283-8.