Table 2.

Multinomial regression analysis of hip data from 270 vignettes with “rarely appropriate” as the reference category.

Classification	AAOS Prognostic/Predictor Variable	Rating for Each Prognostic/Predictor Variable	B	OR
Appropriate	Intercept		−1044.27
	Function-limiting pain	Pain at rest or night	269.14	7.66 × 10¹¹⁶
		Short distances	211.96	1.13 × 10⁹²
		Moderate to long distances	0^a
	Range-of-motion limitation	Severe	85.61	1.51 × 10³⁷
		Moderate	52.00	3.86 × 10²²
		Minimal	0^a
	Risk of negative outcome	No modifiable risk factors	153.92	7.05 × 10⁶⁶
	Risk of negative outcome	Modifiable risk factors	0^a
	Hip radiographic evaluation	Severe OA^b	723.67	> 1.60 × 10³⁰⁸
		Moderate OA	327.61	1.90 × 10¹⁴²
		Minimal OA with FAI	3.71	40.66
		Minimal OA with AD	8.80	6624.08
		Minimal OA	0^a
	Age	Elderly	541.11	1.00 × 10²³⁵
		Middle-aged	326.87	9.08 × 10¹⁴¹
		Young	0^a
May be appropriate	Intercept		−82.54
	Function-limiting pain	Pain at rest or night	24.97	7.00 × 10¹⁰
		Short distances	28.56	2.54 × 10¹²
		Moderate to long distances	0^a
	Range-of-motion limitation	Severe	25.70	1.45 × 10¹¹
		Moderate	21.24	1.68 × 10⁹
		Minimal	0^a
	Risk of negative outcome	No modifiable risk factors	1.97	7.15
	Risk of negative outcome	Modifiable risk factors	0^a
	Hip radiographic evaluation	Severe OA	81.56	2.64 × 10³⁵
		Moderate OA	81.56	2.64 × 10³⁵
		Minimal OA with FAI	3.69	40.08
		Minimal OA with AD	8.76	6402.33
		Minimal OA	0^a
	Age	Elderly	54.04	2.94 × 10²³
		Middle-aged	22.81	8.04 × 10⁹
		Young	0^a

↵a Parameter fixed to zero because it is redundant.
↵b Computing the exponent of the coefficient for severe OA in the “appropriate” relative to “rarely appropriate” classification exceeds computational limits, producing a value of infinity. Therefore, a lower value than the coefficient was used to compute the reported OR. OA: osteoarthritis; AAOS: American Academy of Orthopaedic Surgeons; FAI: femoroacetabular impingement; AD: acetabular dysplasia.