Comparison of Glenoid Dimensions Between 3D Computed Tomography and 3D Printing

INTRODUCTION

Glenoid dimensions can be measured in vivo with various imaging methods including two-dimensional (2D) and three-dimensional computed tomography (CT) and magnetic resonance imaging scans. Printing of three-dimensional (3D) models of the glenoid using imaging data is feasible and can be used to better understand skeletal trauma and complex skeletal deformations such as glenoid bone loss in patients with shoulder instability. The purpose of this study was to compare measurements of glenoid dimensions on 3D CT scan reconstructed models and 3D printed models of the glenoid.

METHODS

CT scans from 62 young, male adults acquired for non-trauma-related causes were evaluated. Following volume rendering, a stereolithography model of each scapula was constructed and a 3D model was printed. Additionally, 3D CT models of each glenoid were reconstructed using dedicated software. Measurements of the maximum glenoid height and width were performed on both the 3D printed and the 3D reconstructed models. To assess intra- and interrater reliability, measurements of 15 glenoids were repeated by two observers after three weeks. The measurements of the 3D printed and 3D reconstructed models were compared.

RESULTS

Inter- and intra-rater reliability was excellent or perfect. Analysis of height and width values demonstrated a strong correlation of 0.91 and 0.89 respectively (p<0.001) for both the 3D printed models and the 3D reconstructed models. There was a strong correlation between the height and width, but no significant difference between the glenoid width and height in both models. There was no statistical significance between height and width when measurements on the two models were examined (p=0.12 and 0.23 respectively).

CONCLUSION

3D printed glenoid models can be used to evaluate the glenoid dimensions, width, and height, as they provide similar accuracy with 3D reconstructed models as provided from CT scan data.

Intra-articular Hip Injection Using Anatomical and Radiological Landmarks Without the Use of Ultrasound or Radiological Guidance

INTRODUCTION

Intra-articular hip injections are routinely performed under sonographic or fluoroscopic guidance in order to improve accuracy. The purpose of this study was to evaluate the safety and accuracy of a hip injection technique that does not require the use of fluoroscopic or ultrasound guidance and can be performed in the clinic. A combination of radiographic and anatomic landmarks was used in order to perform the hip injection, based on the use of simple hip radiographs.

METHODS

In this prospective study 35 patients with hip osteoarthritis or femoroacetabular impingement were included. All patients underwent intra-articular hip joint injection using the technique we describe. The injection location was determined based on measurements performed on hip radiographs using as reference points fixed anatomical landmarks, i.e., the anterior superior iliac spine (ASIS), the cephalic, and caudal femoral head-neck junctions. The vertical distance between the ASIS and the greater trochanter and the horizontal distance between the two head-neck junctions, and the vertical line were also measured. The accuracy of the injection was assessed using ultrasound examination before and after the injection in order to verify intra-articular fluid injection.

RESULTS

Intra-articular hip joint injections using the described non-guided technique were successful in 33 of 35 (94.3%) patients without any complications.

CONCLUSION

 Hip injections can be performed with high accuracy without the need for radiological or ultrasound guidance using the described technique. The combination of radiological and anatomical landmarks to perform intra-articular hip injections is safe, cost-effective, and accurate.

Interobserver and Intraobserver Variability of Four Suprascapular Notch Classification Systems

INTRODUCTION

Knowledge of the morphology of the suprascapular notch is clinically beneficial in patients with suspected suprascapular nerve compression or palsy. Several classification systems have been proposed for the morphological classification of the suprascapular notch and its several anatomical variations. The purpose of this study was to evaluate the inter- and intraobserver reliability of four different classification systems for suprascapular notch typing analysing shoulder computed tomography (CT) scans.

METHODS

Shoulder CT scans from 109 subjects (71.5% males) were examined by three raters of various experience levels, one senior, one experienced, and one junior orthopaedic surgeon. The CT scans were evaluated quantitatively and qualitatively and the suprascapular notch was classified according to four classification systems at two separate timepoints, four weeks apart. To determine consistency among the same or different raters, the Kappa statistic was performed and intrarater reliability for each rater between the first and the second evaluation was assessed using Cohen's kappa. Reliability across all raters at each timepoint was assessed using the Fleiss kappa.

RESULTS

Agreement was almost perfect for all the classification systems and amongst all raters, regardless of their experience level. There were no significant differences between the raters on any of the evaluations. The overall interobserver agreement for all classifications was almost perfect.

CONCLUSION

The four suprascapular notch classification systems are reliable, and the rater's experience level has no impact on the evaluation.