Study on the thermesthesia features of heat-sensitive acupoints in patients with knee osteoarthritis

Objective

To observe the thermesthesia thresholds of the heat-sensitive acupoints in patients with knee osteoarthritis (KOA), and to provide scientific evidence for acupoint selection based on acupoint sensitization.

Methods

Forty-six patients with KOA of swelling type were recruited. By using the quantitative thermesthesia testing, the thermal sensation threshold, thermal pain threshold, and threshold of thermal pain tolerance at Xuehai (SP 10), Neixiyan (EX-LE 4) and Yinlingquan (SP 9) were detected. The subjects were then divided into heat-sensitive groups and non-heat-sensitive groups according to whether there was a phenomenon of heat-sensitive moxibustion sensation at each acupoint, to compare the thermesthesia thresholds between the two groups.

Results

The thermal sensation threshold, thermal pain threshold, and threshold of thermal pain tolerance were respectively (38.21±2.03) °C (44.47±1.8,) °C and (48.59±0.74) °C in the heat-sensitive group of Xuehai (SP 10), versus (36.76±1.93) °C, (42.91±2.05) °C and (46.95±1.14) °C in the non-heat-sensitive group of Xuehai (SP 10); the thermal sensation threshold, thermal pain threshold, and threshold of thermal pain tolerance were respectively (37.47±1.77) °C, (44.55±1.63) °C, and (47.48±0.47) °C in the heat-sensitive group of Neixiyan (EX-LE 4), versus (35.92±1.69) °C, (42.72±1.94) °C and (45.53±0.41) °C in the non-heat-sensitive group of Neixiyan (EX-LE 4); the thermal sensation threshold, thermal pain threshold, and threshold of thermal pain tolerance were respectively (37.30±2.23) °C, (44.39±1.92) °C and (47.76±0.58) °C in the heat-sensitive group of Yinlingquan (SP 9), versus (36.06±1.86) °C, (42.63±1.88) °C and (45.91±0.72) °C in the non-heat-sensitive group of Yinlingquan (SP 9). The statistical analyses showed that the thermal sensation threshold, thermal pain threshold, and threshold of thermal pain tolerance of each heat-sensitive group (all the three acupoints) were significantly higher than those of each corresponding non-heat-sensitive group (P<0.01).

Conclusion

There were differences in the thermesthesia thresholds between heat-sensitized and non-heat-sensitized acupoints in patients with KOA of swelling type; and the thermal sensation threshold, thermal pain threshold, and threshold of thermal pain tolerance of the heat-sensitized points were significantly higher than those of the non-heat-sensitized ones.