Associations among pain catastrophizing, muscle strength, and physical performance after total knee and hip arthroplasty

Table 1 Participant characteristics

	THA	TKA
Sex (male/female)	4/19	9/14
Age	61.17 ± 10.32	69.65 ± 8.52
Height (cm)	155.84 ± 8.34	153.01 ± 10.37
Body weight (kg)	58.66 ± 13.75	60.78 ± 12.87
Body mass index (kg/m2)	24.05 ± 4.30	25.80 ± 4.25

Data for age, height, body weight, and body mass index are presented as mean ± SD. THA: Total hip arthroplasty; TKA: Total knee arthroplasty.

Table 2 Pre- and postoperative data according to site of replacement

	THA			TKA
	Preoperative	Postoperative at 14-d	P-value	Preoperative	Postoperative at 14-d	P-value
TUG (s)	11.51 ± 3.82	13.67 ± 5.65	0.004a	12.22 ± 4.33	16.42 ± 9.09	0.004a
10 m gait speeds at comfortable (m/s)	0.97 ± 0.23	0.92 ± 0.20	0.187	0.99 ± 0.24	0.77 ± 0.23	0.000a
10 m gait speeds at maximum (m/s)	1.28 ± 0.34	1.11 ± 0.32	0.005a	1.19 ± 0.34	0.95 ± 0.32	0.000a
VAS	37.87 ± 24.20	17.61 ± 20.29	0.001a	41.91 ± 27.09	25.22 ± 20.41	0.004a
PCS	28.70 ± 9.28	18.70 ± 11.19	0.000a	28.26 ± 11.90	20.26 ± 10.72	0.003a
Muscle strength (kgf*m)
Hip abductor strength (operated side)	2.62 ± 1.63	2.04 ± 1.36	0.026a	3.49 ± 2.06	2.10 ± 1.63	0.001a
Knee extensor strength (operated side)	4.78 ± 3.19	3.99 ± 1.59	0.240	4.46 ± 2.82	2.55 ± 2.13	0.001a

These data were analyzed with paired t-tests. Data for TUG, 10-m gait speeds, VAS, PCS, and muscle strength are presented as mean ± SD.

^aP < 0.05. THA: Total hip arthroplasty; TKA: Total knee arthroplasty; TUG: Timed Up and Go; VAS: Visual analog scale; PCS: Pain Catastrophizing Scale.

Table 3 Correlation between percent changes from pre- to post-operative physical performance and other variables

	THA				TKA
	ΔTUG (s)	Δ10 m gait speeds at comfortable (m/s)	Δ10 m gait speeds at maximum (m/s)		ΔTUG (s)	Δ10 m gait speeds at comfortable (m/s)	Δ10 m gait speeds at maximum (m/s)
Preoperative				Preoperative
VAS	r = 0.184	0.083	-0.025	VAS	r = 0.237	-0.177	-0.287
	P = 0.402	0.707	0.908		P = 0.276	0.419	0.184
PCS	r = 0.270	0.021	-0.119	PCS	r = -0.184	0.122	0.169
	P = 0.213	0.923	0.588		P = 0.400	0.579	0.442
Hip abductor strength (operated side, kg·f)	r = 0.063	-0.165	-0.161	Hip abductor strength (operated side, kg·f)	r = -0.168	0.142	0.084
	P = 0.774	0.452	0.464		P = 0.444	0.517	0.703
Knee extensor strength (operated side, kg·f)	r = 0.044	-0.235	-0.278	Knee extensor strength (operated side, kg·f)	r = -0.077	0.070	-0.102
	P = 0.842	0.281	0.199		P = 0.726	0.751	0.643
Percent changes				Percent changes
ΔVAS	r = 0.225	-0.093	-0.212	ΔVAS	r = 0.085	-0.265	-0.129
	P = 0.302	0.672	0.332		P = 0.699	0.221	0.558
ΔPCS	r = 0.117	-0.042	-0.047	ΔPCS	r = 0.495	-0.583	-0.427
	P = 0.594	0.849	0.831		P = 0.016a	0.003a	0.042a
ΔHip abductor strength (operated side, kg·f)	r = -0.418	0.642	0.479	ΔHip abductor strength (operated side, kg·f)	r = -0.333	0.373	0.546
	P = 0.047a	0.001a	0.021a		P = 0.121	0.079	0.007a
ΔKnee extensor strength (operated side, kg·f)	r = -0.247	0.434	0.530	ΔKnee extensor strength (operated side, kg·f)	r = -0.389	0.474	0.656
	P = 0.257	0.038a	0.009a		P = 0.066	0.022a	0.001a

These data were analyzed by the Pearson r rank test, with the r value as the correlation coefficient;

^aP < 0.05. THA: Total hip arthroplasty; TKA: Total knee arthroplasty; TUG: Timed Up and Go; VAS: Visual analog scale; PCS: Pain catastrophizing scale.