Fig. 3.

a Initial 3D rendering of the segmentation result of the MCP 4 joint of a 72-years-old male, diagnosed with HH 31 years ago. The metacarpal head is depicted in light blue, while the base of the proximal phalanx is shown in dark blue. The local joint space width was mapped in the joint space in pseudo-color. Blue and green colors reflect a narrow joint space width, while red colors code for a broader joint space width. Note the very narrow and irregular joint space depicted in light green. b Final 3D surface reconstruction of the MCP 3 joint of a 55-years-old male (BMI 21.9 kg/m²) diagnosed with HH 8 years ago. The local joint space width was mapped in the joint space in pseudo-color. Blue and green colors reflect a narrow joint space width, while red colors signify a broader joint space width