Table 4.

Multilevel linear regression of factors associated with PROMIS Physical Function including PCS, accounting for nesting by clinic location

	Regression coefficient (95% CI)	p value	Δ-AIC
Pain Catastrophizing Scale	-0.34 (-0.68 to 0.00)	0.053	1.7
Employment status
Unemployed, student, or retired	Reference value
Employed	3.08 (0.23 to 5.94)	0.03	2.4
Assistive devices
Crutches	Reference value		12.5
Knee scooter	1.44 (-4.24 to 7.11)	0.62
Walker	-2.64 (-6.75 to 1.46)	0.21
Other	1.82 (-2.41 to 6.05)	0.40
None	7.52 (3.66 to 11.38)	< 0.001
Weightbearing status			6.5
Full weightbearing	Reference value
Nonweightbearing	-6.30 (-10.03 to -2.58)	0.001
Partial weightbearing	-2.64 (-6.31 to 1.03)	0.16

SHAI and PROMIS Depression have been dropped because of multicollinearity with PCS. Week to injury and insurance status have been dropped due to multicollinearity with weightbearing status and employment status, respectively. Δ AIC = Akaike Information Criterion; AIC of the full model was compared to the model without each variable. Higher values indicate better fit.