HIPPO artificial intelligence: Correlating automated radiographic femoroacetabular measurements with patient-reported outcomes in developmental hip dysplasia

Table 1 Patient-reported outcome measures surveys

Survey	Description
HHS	The HHS is a joint-specific 10-question survey evaluating hip function. The survey parameters include- ability to climb stairs, take public transport, and put on shoes and socks. The test has been shown to have strong construct validity, and thus would be appropriate as a comprehensive assessment of the affected joint’s impact on the patient[16]
SF-12	The SF-12 survey, which was adapted from the SF-36 survey, assesses the patient’s view of their own health and how it relates to their lifestyle. It includes questions, such as asking the patient if they achieved as much as they have liked and whether they have felt calm and peaceful. Thus, the SF-12 can provide insight into the psychological aspect of the patient’s condition[20]
IHOT-12	The iHOT-12 is a 12-question survey adapted from the 33-question survey. The survey evaluates quality of life changes[21]
EQ-VAS	EQ-VAS is a scale from 0 (worst health) to 100 (best health) that allows the patient to indicate their overall perspective of their health state[22]

IHOT: International hip outcome tool; EQ-VAS: Visual Analogue Scale of the European Quality of Life Group; HHS: Harris hip score; SF: Short form.

Table 2 HIPPO radiographic hip measurements and landmarks

Measurement	Description
CCD	The CCD angle was measured as the angle between the femur neck and shaft axis[23]
Pelvic obliquity	The pelvic obliquity was measured with a tangential line from the apex of the femoral heads and a line parallel to the horizontal plane as in Figure 1
Sharps angle	Sharp’s angle was measured with a line connecting the inferior ischial tuberosities and a line connecting the lower medial edge of the acetabular teardrop and the lateral edge of acetabular sourcil[23]
LCEA	The LCEA was measured as a perpendicular line through the center of the femoral head perpendicular to the acetabular tuberosities and the angle between a line from the center of the femoral head to the lateral acetabular sourcil[24]
Extrusion index	The extrusion index was measured by the difference of medial and lateral femoral head and the lateral edge sourcil with three vertical lines at edge aspect. The femoral head coverage was represented by the percentage of femoral head covered: Lateral femoral head to lateral edge sourcil distance minus the total horizontal head diameter[23]
Tönnis angle	The Tönnis angle was measured as the angle between a line connecting the inferior and lateral aspects of the acetabular sourcil and a line connecting the inferior portion of the ischial tuberosities[12]

CCD: Caput-Collum-Diaphyseal; LCEA: Lateral center edge angle.

Table 3 Spearman correlation between manual hip measurements and various patient-reported outcome measures surveys

Patient-reported outcome measures	Hip measures	Estimate	Lower 95%CI	Upper 95%CI	Raw P value	Adjusted P value
Visual Analogue Scale of the European Quality of Life Group	CCD	0.07	-0.11	0.25	0.450	0.802
	Extrusion index	0.02	-0.16	0.20	0.823	0.823
	LCEA	-0.04	-0.22	0.15	0.688	0.823
	Obliquity	-0.17	-0.34	0.01	0.063	0.378
	Sharp	0.06	-0.13	0.24	0.535	0.802
	Tönnis	-0.08	-0.25	0.11	0.419	0.802
Harris hip score	CCD	0.02	-0.16	0.20	0.791	0.791
	Extrusion index	-0.14	-0.31	0.04	0.122	0.183
	LCEA	0.18	0.00	0.35	0.049	0.147
	Obliquity	-0.16	-0.33	0.02	0.081	0.162
	Sharp	-0.06	-0.24	0.12	0.493	0.592
	Tönnis	-0.24	-0.40	-0.06	0.009	0.054
International hip outcome tool	CCD	-0.19	-0.36	0.00	0.045	0.270
	Extrusion index	-0.03	-0.21	0.16	0.764	0.999
	LCEA	0.00	-0.18	0.18	0.999	0.999
	Obliquity	0.13	-0.06	0.30	0.183	0.549
	Sharp	0.00	-0.18	0.18	0.998	0.999
	Tönnis	0.07	-0.12	0.25	0.469	0.938
Short form 12	CCD	0.19	0.01	0.36	0.042	0.252
	Extrusion index	0.03	-0.16	0.21	0.778	0.870
	LCEA	-0.03	-0.22	0.15	0.720	0.870
	Obliquity	-0.13	-0.30	0.06	0.186	0.558
	Sharp	0.06	-0.13	0.24	0.530	0.870
	Tönnis	-0.02	-0.20	0.17	0.870	0.870

CCD: Caput-Collum-Diaphyseal; LCEA: Lateral center edge angle.

Table 4 Spearman correlation between artificial intelligence hip measurements and various patient-reported outcome measures surveys

Patient-reported outcome measures	Hip measures	Estimate	Lower 95%CI	Upper 95%CI	Raw P value	Adjusted P value
Visual Analogue Scale of the European Quality of Life Group	CCD	0.09	-0.09	0.27	0.330	0.509
	Extrusion index	0.07	-0.11	0.25	0.424	0.509
	LCEA	-0.09	-0.27	0.10	0.354	0.509
	Obliquity	-0.22	-0.39	-0.04	0.015	0.090
	Sharp	0.06	-0.13	0.23	0.557	0.557
	Tönnis	-0.11	-0.29	0.07	0.235	0.509
Harris hip score	CCD	0.11	-0.07	0.28	0.238	0.286
	Extrusion index	-0.15	-0.32	0.03	0.112	0.255
	LCEA	0.13	-0.05	0.30	0.170	0.255
	Obliquity	-0.13	-0.30	0.05	0.154	0.255
	Sharp	-0.03	-0.21	0.15	0.723	0.723
	Tönnis	-0.20	-0.36	-0.02	0.033	0.198
International hip outcome tool	CCD	-0.25	-0.42	-0.07	0.007	0.042a
	Extrusion index	0.03	-0.15	0.22	0.718	0.718
	LCEA	-0.05	-0.23	0.14	0.608	0.718
	Obliquity	0.17	-0.02	0.34	0.079	0.237
	Sharp	0.04	-0.15	0.22	0.703	0.718
	Tönnis	0.05	-0.13	0.24	0.565	0.718
Short form 12	CCD	0.25	0.07	0.42	0.008	0.048c
	Extrusion index	0.00	-0.18	0.19	0.972	0.972
	LCEA	-0.07	-0.25	0.12	0.476	0.714
	Obliquity	-0.16	-0.34	0.02	0.088	0.264
	Sharp	0.08	-0.10	0.26	0.385	0.714
	Tönnis	0.02	-0.16	0.21	0.817	0.972

^aP < 0.05.

^cP < 0.001.

CCD: Caput-Collum-Diaphyseal; LCEA: Lateral center edge angle.