Table 6 Studies Assessing Hill-Sachs Bone Loss with Radiography, CT and MRI

Charousset et al. [47]: Retrospective case series

26 patients

Quantitative assessment:

P/R ratio reliability:

Assessment:

P/R ratio on true AP radiography in internal rotation (Fig. 10)

Inter-observer ICC 0.81-0.92

3 observers measured twice

Qualitative assessment:

Intra-observer ICC 0.72-0.97

Outcome:

True AP radiograph in external rotation (present or absent lesion)

Qualitative assessment reliability:

Reliability

Inter-observer ICC 0–0.30

Intra-observer ICC 0.06-0.92

Note: Simple patient positioning and reliable

Ito et al. [38]: Retrospective case series

27 patients (30 shoulders)

Width and depth of Hill-Sachs lesion measured:

Width difference (p > 0.05) :

Assessment:

Supine position; arm 135 ° flexion, 15 ° internal rotation; radiography beam perpendicular

Dislocation group 13.4 mm+/−2.5 mm

Divided into 2 groups: dislocation (11) and dislocation with recurrent subluxation (19); 1 observer measured once

Note: Patient positioning may be cumbersome and difficult to replicate in a clinical setting

With subluxation group 13.8+/−3.5 mm

Outcome:

Depth difference (p < 0.05):

Width difference

Dislocation group 3.9+/−0.9 mm

With subluxation group 2.1+/−1.0 mm

Note: Deeper lesions associated with subjective joint laxity but not number of dislocations

Kralinger et al. [39]: Retrospective cohort study

166 patients

Hill-Sachs Quotient:

Recurrence rate associated with Hill-Sachs Quotient:

Assessment:

Bernageau view and AP view at 60 ° internal rotation (Fig. 8)

Grade I 23.3 %

1 observer measured once

Grade II 16.2 %

Outcome:

Grade III 66.7 %

Recurrence rate

Sommaire et al. [46]: Retrospective cohort study

77 patients

d/R ratio:

Risk of recurrence (p = 0.016):

Assessment:

True AP radiograph in internal rotation (similar to Charousset et al. [2010]; Fig. 9)

9.6 % in d/R ratio <20 %

Final clinical outcome after arthroscopic Bankart repair and imaging; 1 observer measured once

40 % in d/R ratio >20 %

Outcome:

Note: d/R ratio predictive of failure of arthroscopic Bankart repair

Need for revision repair

Hardy et al. [37]: Retrospective cohort study

59 patients

Radiograph 45 ° internal rotation view:

d/R ratio (p < 0.01):

Assessment:

Depth of defect/radius of humerus (d/R) ratio (similar to Charousset et al. [2010])

Good/excellent group: 16.2 %

After arthroscopic stabilization divided into 2 groups based on Duplay clinical functional score: good/excellent (38) fair/poor (21); 1 observer measured all patients once; 10 observers measured 10 patients

CT:

Poor/fair group: 21.3 %

Outcome:

Humeral head radius (best-fit circle to circumference); defect width; defect depth (from edge of circle); defect length (amount of CT slices with the defect); lateralization angle (compared to AP line through center of head)

Mean volume of lesion (p < 0.001):

Correlation of clinical score with radiographic findings; surgical failure rate

Note: Radiographic technique easily obtained

Good/excellent group: 640 mm³

Poor/fair group: 2160 mm³

Surgical failure rate:

d/R >15 %: 56 %

d/R < 15 %: 16 %

Presence of lesion, depth, lateralization angle, lesion, and humeral head volume ratio all non-significant between groups

Reliability :

Inter-observer reliability for depth and radius measurements non-significant

Kodali et al. [72]: Laboratory study

6 anatomic bone substitute models

Circle fit to humeral head:

Inter-observer reliability ICC:

Assessment:

Width and depth measured on sagittal, axial, and coronal planes (similar to Saito et al. (2009)

Depth - 0.879

Circular humeral head defects created; 2DCT width-depth measurements made in 3 planes and compared to the defect sizes measured by a 3D laser scanner

Width 0.721

Outcome:

Accuracy (PE):

5 observers measured once

Width: sagittal 10.9+/−8.6 %, axial 10.5+/−4.4 %, coronal 15.9+/−8.6 %;

Depth: sagittal 12.7+/−10.0 %, axial 16.7+/−10.2 %,coronal 22.5+/−16.6 %

Saito et al. [12]: Retrospective case-controls study

35 patients; 13 normal

Circle fit to the humeral head on axial slices:

Mean size of Hill-Sachs lesion:

Assessment:

Depth: greatest length of distance from floor of defect to edge of circle; width: measured between edges of defect

Depth 5.0+/−4.0 mm; width 22+/−6 mm

1 observer measured 3 times

Intra-observer reliability:

Outcome:

Pearson correlation coefficient: 0.954-0.998

Reliability

Coefficient of variation: 0–7.4 %.

Cho et al. [36]: Prospective cohort study

104 patients (107 shoulders)

Fit circle to articular surface of humeral head:

Inter-observer reliability:

Assessment:

Axial and coronal planes: width and depth measured on axial and coronal slice where lesion was largest

ICC 0.629-0.992

evaluated size, orientation, & location as means to predict engagement; engagement defined arthroscopically; 1 observer measured 27 randomly selected shoulders 3 times; 2nd observer measured once

Intra-observer reliability:

Outcome:

ICC 0.845-0.998

Reliability, size of Hill-Sachs lesion relationship to engaging lesions

Size of Hill-Sachs lesion (axial):

Engaging group width 52 % & depth 14 %

Non-engaging group width 40 % & depth 10 % (both p <0.001)

Size of Hill-Sachs lesion (coronal):

Engaging group width 42 % & depth 13 %

Non-engaging group width 31 %, & depth 11 % (p = 0.012 & 0.007 respectively).

Note: Orientation of Hill-Sachs angle significantly higher in engaging lesions

Kawasaki et al. [73]: Modeling

Evaluated 7 CT scans of bilateral shoulders

Created 3D contour; mirrored the normal shoulder and overlap contours; computer measured defect difference

Proposed a method to calculate humeral head bone loss

Kirkley et al. [70]: Prospective case series

16 patients

Hill-Sachs lesions were categorized as small (<1 cm) or large (>1 cm);

Presence vs. absence of Hill-Sachs lesion:

Assessment:

Note: Did not clarify slice or dimensions measured to determine Hill-Sachs lesion size

Kappa = 1

MRI followed by arthroscopic evaluation; 2 observers measured once

Distinguishing small from large lesion:

Kappa = 0.44

Outcome:

Not able to accurately quantify size

Reliability

Salomonsson et al. [71]: Prospective cohort study

51 patients

Hill-Sachs depth:

Size of Hill-Sachs lesion:

Assessment:

Measured on axial slice at largest point

Stable group 5 mm; unstable group 3 mm (non-significant)

MRI immediately and clinical follow-up to 105 months; divided into stable and unstable (recurrent instability); 2 observers measured once

Outcome:

Size of Hill-Sachs lesion correlation with recurrent instability