Table 2.

Spearman’s rank correlation coefficients between synovial fluid and serum pain mediators and clinical variables of osteoarthritic pain

Variable	SF PGE2	Serum PGE2	SF SP	Serum SP	PVF	VI	HCPI	Pain on palpation
SF PGE2	1.00	0.23	0.10	−0.05	−0.62*	−0.61*	0.05	0.45*
Serum PGE2	0.23	1.00	−0.11	−0.48*	0.03	0.04	−0.08	−0.14
SF SP	0.10	−0.11	1.00	0.09	−0.02	0.02	0.02	−0.09
Serum SP	−0.05	−0.48*	0.09	1.00	0.12	0.10	−0.03	−0.04

SF synovial fluid, PGE ₂ prostaglandin E₂, SP substance P, PVF peak vertical force, VI vertical impulse, HCPI Helsinki Chronic Pain Index, Pain on palpation = subjective evaluation of pain on palpation of the joint. *P < 0.05