Ultrasound-guided Pulsed Radiofrequency of the Saphenous Nerve for Knee Osteoarthritis Pain: A Pilot Randomized Trial

Figures & data

Figure 1. Recruitment and flow of participants throughout the trial.

Table 1. Clinical and demographical characteristics at screening of 16 participants who completed both arms of the crossover intervention.

Clinical and demographical variables	At baseline (n = 16)	Real PRF at baseline (n = 8)	Sham PRF at baseline (n = 8)	Differences between sham and real PRF p-value
Age (years) (m ± SD)	70.63 ± 9.51	70.37 ± 7.36	70.87 ± 11.81	0.908
Gender (males/females)	(5/11)	(2/6)	(3/5)	NA
BMI (kg/m^2) (m ± SD)	29.56 ± 3.83	29.48 ± 4.42	29.62 ± 3.43	0.953
Pain duration (months) (m ± SD)	10 ± 3.18	9.62 ± 2.06	10.37 ± 1.92	0.544
Primary outcome (pain intensity)
Numerical rating scale (m ± SD)	8.03 ± 1.01	8.25 ± 0.70	8 ± 1.19	0.668
Secondary outcomes (function and quality of life)
Oxford Knee Score (m ± SD)	17 ± 8.26	19.5 ± 10.70	15.75 ± 4.55	0.409
SF-36 Physical functioning (m ± SD)	33.12 ± 23.65	31.25 ± 15.97	36.12 ± 29.45	0.725
SF-36 Role limitations from physical health (m ± SD)	17.18 ± 31.62	16.25 ± 24.78	19.62 ± 36.35	0.837
SF-36 Pain (m ± SD)	26.48 ± 13.61	27.87 ± 15.81	25.87 ± 11.10	0.799
SF-36 General health (m ± SD)	35.93 ± 16.93	36.95 ± 13.75	37.03 ± 18.47	0.992
SF-36 Energy/fatigue (m ± SD)	36.56 ± 18.36	39.25 ± 23.66	32.81 ± 10.22	0.424
SF-36 Social functioning (m ± SD)	48.82 ± 26.68	57.62 ± 28.93	40.06 ± 20.90	0.255
SF-36 Role limitations from emotional problems (m ± SD)	33.33 ± 42.17	32.87 ± 41.64	33.56 ± 38.83	0.932
SF-36 Emotional well-being (m ± SD)	53.62 ± 22.12	50.62 ± 26.10	56. 62 ± 17.25	0.600

BMI: Body mass index; m: Mean; NA: Not applicable; PRF: Pulsed radiofrequency; SD: Standard deviation; SF-36: 36-Item Short Form Health Survey Questionnaire.

Figure 2. Within-groups variation of pain intensity and OKS at study time-points compared to baseline.

(A) Pain Intensity measured by NRS at study time points (baseline [T0] and after 2 weeks [T1], 1 month [T2], 3 months [T3] and 6 months [T4]). A statistically significant pain reduction was observed only after real PRF until 1-month after the procedure. (B) OKS at study time points (baseline [T0] and after 2 weeks [T1], 1 month [T2], 3 months [T3] and 6 months [T4]). A statistically significant improvement of function was observed only after real PRF until 3 months after the procedure.

m: Mean; NRS: Numerical rating scale; OKS: Oxford Knee Score; PRF: Pulsed radiofrequency; SD: Standard deviation.

Table 2. SF-36 domains at study time points (baseline [T0], after 2 weeks [T1], 1 month [T2], 3 months [T3] and 6 months [T4]).

Real PRF	T0–T1 Mean change (95% CI for difference)	p-value	T0–T2 Mean change (95% CI for differences)	p-value	T0–T3 Mean change (95% CI for differences)	p-value	T0–T4 Mean change (95% CI for differences)	p-value
SF-36 Items
Physical functioning (m ± SD)	-6.25 (-10.96 to -1.63)	ns	-15.31 (-26.59 to -4.03)	ns	-5 (-13.70–3.70)	ns	-7.03 (-18.43–4.36)	ns
Role of limitations from physical health (m ± SD)	-1.5 (-10.62–7.49)	ns	-3.12 (-14.91–8.66)	ns	3.12 (-13.63–19.88)	ns	8.75 (-10.76–28.26)	ns
Pain (m ± SD)	-11.25 (-18.14 to -4.35)	0.003	-17.34 (-25.50 to -9.18)	<0.001	-16.87 (-27.40 to -6.34)	0.004	-18.48 (-26.56 to -10.40)	<0.001
General health (m ± SD)	-1.25 (-6.53–4.03)	ns	-6.56 (-13.14–0.01)	ns	-5.31 (-10.50 to -0.12)	ns	-5 (-12.78–2.78)	ns
Energy/fatigue (m ± SD)	-1.87 (-7.87–4.11)	ns	-10 (-20.44–0.44)	ns	-2.81 (-10.77–5.14)	ns	-1.87 (-8.62–4.87)	ns
Social functioning (m ± SD)	-3.90 (-15.99–8.18)	ns	-6.25 (-15.97–3.47)	ns	-9.37 (-18.63 to -0.11)	ns	-9.37 (-25.23–6.48)	ns
Role of limitations from emotional problems (m ± SD)	-10.93 (-33.08–11.22)	ns	-18.74 (-34.58 to -2.89)	ns	-39.58 (-65.71 to -13.45)	ns	-25 (-50.54–0.54)	ns
Emotional well-being (m ± SD)	-7 (-14.40–0.40)	ns	-2.18 (-8.49–4.11)	ns	-12.50 (-23.16 to -1.83)	ns	-11.87 (-24.92–1.17)	ns
Sham PRF	T0–T1 Mean change (95% CI for difference)	p-value	T0–T2 Mean change (95% CI for differences)	p-value	T0–T3 Mean change (95% CI for differences)	p-value	T0–T4 Mean change (95% CI for differences)	p-value
Physical functioning (m ± SD)	3.75 (-10.39–17.89)	ns	0.93 (-9.77–11.64)	ns	2.81 (-8.69–14.32)	ns	3.43 (-8.02–14.89)	ns
Role of limitations from physical health mean (SD)	-7.81 (-22.97–7.35)	ns	-3.12 (-17.61–11.36)	ns	0 (-16.13–16.13)	ns	-3.64 (-21.10–13.81)	ns
Pain (m ± SD)	-6.56 (-13.55–0.43)	ns	-5.93 (-13.37–1.50)	ns	-2.96 (-10.69–4.75)	ns	-1.71 (-10.52–7.08)	ns
General health (m ± SD)	-0.93 (-9.86–7.99)	ns	0.93 (-9.22–11.10)	ns	-1.56 (-12.11–8.99)	ns	-0.31 (-11.20–10.58)	ns
Energy/fatigue (m ± SD)	3.75 (-1.25–8.75)	ns	2.50 (-3.80–8.80)	ns	4.68 (-1.42–10.79)	ns	3.75 (-2.20–9.70)	ns
Social functioning (m ± SD)	-4.68 (-11.06–1.68)	ns	-4.68 (-12.33–2.95)	ns	3.12 (-6.45–12.70)	ns	4.06 (-6.50–14.62)	ns
Role of limitations from emotional problems (m ± SD)	-12.49 (-25.25–0.26)	ns	-20.82 (-40.14 to -1.50)	ns	-31.25 (-59.87 to -2.62)	ns	-22.90 (-50.96–5.15)	ns
Emotional well-being (m ± SD)	-7 (-16.09–2.09)	ns	-7 (-17.27–3.25)	ns	-7 (-17.25–3.25)	ns	-5.75 (-16.81–5.31)	ns

m: Mean; PRF: Pulsed radiofrequency; SD: Standard deviation.

Table 3. Between groups changes in primary and secondary outcomes (ANOVA with repeated measures).

		Time points					Time X group	Time
		T0	T1	T2	T3	T4
NRS scores	rPRF (n = 16)	7.93 ± 1.06	4.93 ± 1.8	4.62 ± 2.44	6 ± 2.9	6.9 ± 1.7	F(4,27) = 2.76, p = 0.04^†	F(4,27) = 12.26, p < 0.001^†
	sPRF (n = 16)	8.1 ± 0.9	6.9 ± 1.7	7 ± 1.8	7.5 ± 1.9	7.6 ± 1.7
OKS scores	rPRF (n = 16)	16.33 ± 8.80	26.58 ± 10.18	28.5 ± 11.05	24.25 ± 11.09	23.5 ± 10.32	F(4,27) = 4.28, p < 0.001^†	F(4,27) = 8.50, p < 0.001^†
	sPRF (n = 16)	17.4 ± 8.15	19.65 ± 9.4	22.35 ± 8.45	22.05 ± 7.65	20.15 ± 6.36
SF-36 Physical functioning	rPRF (n = 16)	34.37 ± 21.67	40.62 ± 22.57	49.68 ± 23.63	39.37 ± 22.86	41.40 ± 19.87	F(4,27) = 1.31, p = 0.289	F(4,27) = 1.16, p = 0.347
	sPRF (n = 16)	31.87 ± 25.68	28.12 ± 18.51	30.93 ± 17.14	29.06 ± 14.85	28.43 ± 14.80
SF-36 Role limitations from physical health	rPRF (n = 16)	23.43 ± 35.90	25 ± 31.02	26.56 ± 32.23	20.31 ± 29.18	14.68 ± 28.60	F(4,27) = 1.22, p = 0.322	F(4,27) = 0.461, p = 0.764
	sPRF (n = 16)	10.93 ± 27.33	18.75 ± 30.95	14.16 ± 18.18	10.93 ± 18.13	14.58 ± 22.66
SF-36 Pain	rPRF (n = 16)	24.84 ± 12.39	36.09 ± 15.94	42.18 ± 18.94	41.71 ± 19.86	43.33 ± 14.81	F(4,27) = 2.53, p = 0.6	F(4,27) = 5.32, p < 0.001^†
	sPRF (n = 16)	28.12 ± 14.81	34.68 ± 20.16	34.06 ± 19.16	31.09 ± 15.86	29.84 ± 18.15
SF-36 General health	rPRF (n = 16)	35 ± 13.54	36.25 ± 9.91	41. 56 ± 11.93	40.31 ± 10.87	40 ± 8.94	F(4,27) = 1.14, p = 0.35	F(4,27) = 1.66, p = 0.187
	sPRF (n = 16)	36.87 (20.32)	37.81 ± 17.22	35.93 ± 15.29	38.43 ± 10.11	37.18 ± 9.30
SF-36 Energy/fatigue	rPRF (n = 16)	36.25 ± 17.17	38.12 ± 14.70	38.43 ± 12.20	39.06 ± 13.31	39.06 ± 13.31	F(4,27) = 12.38, p < 0.001^†	F(4,27) = 11.97, p < 0.001^†
	sPRF (n = 16)	36.25 ± 19.53	32.5 ± 19.74	33.75 ± 18.02	62.25 ± 17.15	32.5 ± 15.91
SF-36 Social functioning	rPRF (n = 16)	50.78 ± 30.77	54.68 ± 25.76	57.03 ± 27.37	60.15 ± 21.99	60.81 ± 17.80	F(4,27) = 0.80, p = 0.195	F(4,27) = 0.91, p = 0.468
	sPRF (n = 16)	46.87 ± 22.59	51.56 ± 25.57	51.56 ± 23.2	43.75 ± 19.36	42.81 ± 20.75
SF-36 Role of limitations from emotional problems	rPRF (n = 16)	33.33 ± 42.17	44.26 ± 38.34	52.08 ± 43.67	72.91 ± 36.95	58.33 ± 33.34	F(4,27) = 0.14, p = 0.966	F(4,27) = 4.42, p < 0.001^†
	sPRF (n = 16)	33.33 ± 42.17	45.83 ± 43.67	54.16 ± 38.25	64.58 ± 35.42	56.24 ± 35.95
SF-36 Emotional well-being	rPRF (n = 16)	52 ± 23.41	59 ± 16.42	62 ± 18.41	64.50 ± 17.51	63.87 ± 16	F(4,27) = 0.51, p = 0.72	F(4,27) = 2.10, p = 0.10
	sPRF (n = 16)	55.25 ± 20.82	62.25 ± 19.75	58.25 ± 12.97	62.25 ± 17.15	61 ± 17.37

† p = 0.05.

T0: Baseline; T1: 2-weeks post PRF; T2: 1 month post PRF; T3: 3 months post PRF; T4: 6 months post PRF; NRS: Numerical Rating Scale; OKS: Oxford Knee Score; rPRF: Real pulsed radiofrequency; SF-36: 36-item Short Form Health Survey Questionnaire; sPRF: Sham pulsed radiofrequency.

Data sharing statement

The authors certify that this manuscript reports original clinical trial data. Deidentified, individual data that underlie the results reported in this article (text, tables, figures and appendices), along with the study protocol, will be available for meta-analyses for five years following publication. Parties seeking access to this information should submit a formal request to the corresponding author of this study.