Short-term effectiveness of high- and low-intensity percutaneous electrolysis in patients with patellofemoral pain syndrome: A pilot study

Table 1 Sociodemographic features of the total sample and by group

	Subjects, n (%)	Age (yr)	Height (m)	Weight (kg)	BMI (kg/m2)
Sample	15 (100)	25.6 ± 1.9	1.73 ± 0.05	73.5 ± 6.7	24.4 ± 1.6
Intervention group
HIPE	5 (33.3)	25.4 ± 2.3	1.71 ± 0.05	72.0 ± 7.7	24.5 ± 2.1
LIPE	5 (33.3)	26.8 ± 1.4	1.75 ± 0.04	75.9 ± 6.1	24.6 ± 1.4
DN	5 (33.3)	24.8 ± 1.8	1.73 ± 0.05	72.8 ± 6.9	24.1 ± 1.6

HIPE: High-intensity percutaneous electrolysis; LIPE: Low-intensity percutaneous electrolysis; DN: Dry needling; BMI: Body mass index.

Table 2 Pain pressure thresholds

Variable	Time of measurement	HIPE	LIPE	DN	Mean difference	ANOVA interaction effect	Bonferroni post-hoc analysis
MTrP (kg/cm2)	Pre	4.20 ± 0.57	4.10 ± 0.54	3.80 ± 0.67	0.10 (-0.95-1.15)1; 0.40 (-0.65-1.45)2; 0.30 (-0.75-1.35)1	F = 0.65; P = 0.562; η2 = 0.09	Group	NA
	Post	3.50 ± 0.61	3.60 ± 0.41	4.00 ± 0.35	0.10 (-0.73-0.93)1; 0.50 (-0.33-1.33)2; 0.40 (-0.43-1.23)3	F = 1.55; P = 0.251; η2 = 0.20	Time
	7 d follow-up	5.00 ± 1.00	5.00 ± 0.50	4.50 ± 0.70	0.00 (-1.34-1.34)1; 0.50 (-0.84-1.84)2; 0.50 (-0.84-1.84)3	F = 0.71; P = 0.509; η2 = 0.10		Follow up > post, P < 0.0014,5
Patellar tendon (kg/cm2)	Pre	5.20 ± 0.83	5.30 ± 0.27	5.20 ± 0.83	0.10 (-1.13-1.33)1; 0.00 (-1.23-1.23)2; 0.10 (-1.13-1.33)3	F = 0.03; P = 0.967; η2 = 0.00	Group	NA
	Post	4.90 ± 1.19	4.70 ± 0.44	5.00 ± 0.79	0.20 (-1.32-1.72)1; 0.10 (-1.42-1.62)2; 0.30 (-1.22-1.82)3	F = 0.15; P = 0.858; η2 = 0.02	Time	Follow-up > pre, P < 0.0014,5,6
	7 d follow-up	9.10 ± 0.82	9.50 ± 0.35	9.00 ± 0.86	0.40 (-1.66-0.86)1; 0.10 (-1.16-1.36)2; 0.50 (-0.76-1.76)3	F = 0.67; P = 0.526; η2 = 0.10		Follow-up > post, P < 0.0014,5,6

¹High-intensity percutaneous electrolysis (HIPE) vs low-intensity percutaneous electrolysis (LIPE).

²HIPE vs dry needling (DN).

³LIPE vs DN.

⁴Simple within-group effects in the HIPE group.

⁵Simple within-group effects in the LIPE group.

⁶Simple within-group effects in the DN group.

MTrP: Myofascial trigger point; HIPE: High-intensity percutaneous electrolysis; LIPE: Low-intensity percutaneous electrolysis; DN: Dry needling; ANOVA: One-way analysis of variance.

Table 3 Subjective anterior knee pain perception

Variable	Time of measurement	HIPE	LIPE	DN	Mean difference	ANOVA interaction effect	Group: Bonferroni post-hoc analysis; time: Student t-test
VAS (0-10)	Pre	4.2 ± 0.5	4.5 ± 1.0	4.6 ± 1.3	0.3 (-1.6-2.1)1; 0.3 (-1.5-2.2)2; 0.1 (-1.8-1.9)3	F = 0.14; P = 0.868; η2 = 0.02	Group	NA
	7 d follow-up	2.9 ± 0.9	2.8 ± 0.7	3.2 ± 0.9	0.1 (-1.5-1.6)1; 0.3 (-1.2-1.9)2; 0.4 (-1.1-1.9)3	F = 0.30; P = 0.741; η2 = 0.05	Time	Follow up < pre, P < 0.054,5

¹High-intensity percutaneous electrolysis (HIPE) vs low-intensity percutaneous electrolysis (LIPE).

²HIPE vs dry needling (DN).

³LIPE vs DN.

⁴Simple within-group effects in the HIPE group.

⁵Simple within-group effects in the LIPE group.

VAS: Visual Analogue Scale; HIPE: High-intensity percutaneous electrolysis; LIPE: Low-intensity percutaneous electrolysis; DN: Dry needling; ANOVA: One-way analysis of variance.

Table 4 Pain induced during the interventions

Variable	HIPE (n = 5)	LIPE (n = 5)	DN (n = 5)	Mean difference (95%CI)	ANOVA interaction effect	Bonferroni post-hoc analysis
VAS (0-10)	3.2 ± 0.8	3.2 ± 0.8	5.0 ± 1.1	0.0 (-1.4-1.4)11.80 ± (-3.2--0.4)21.80 (-3.2--0.4)3	F = 8.52; P = 0.005; η2 = 0.587	Group	P < 0.014,5

¹High-intensity percutaneous electrolysis (HIPE) vs low-intensity percutaneous electrolysis (LIPE).

²HIPE vs dry needling (DN).

³LIPE vs DN.

⁴Simple between-group effects between HIPE and DN.

⁵Simple between-group effects between LIPE and DN.

VAS: Visual Analogue Scale; HIPE: High-intensity percutaneous electrolysis; LIPE: Low-intensity percutaneous electrolysis; DN: Dry needling; ANOVA: One-way analysis of variance.