The effect of cold air application on intra-articular and skin temperature in the knee

The present study was performed to investigate the effect on the skin and the intra-articular structures of 5-minutes of cold air application. During and after 5 minutes of cold air application on 20 healthy subjects, the skin and intra-articular temperatures were measured by means of an infrared thermogram and a digital k-wire probe, respectively. The results showed that 1) Skin temperature dropped very rapidly by a total of 22.1 °C after 5 minutes of cold air application. 2) Intra-articular temperature dropped by 3.9 °C after 5 minutes of cold air application. 3) Two hours after the start of treatment with cold air, intra-articular temperatures had still not returned to their baseline values (p < 0.01). 4) The baseline skin temperature and the baseline intra-articular temperature were significantly correlated r=0.51 (p<0.05). However, there was no significant correlation between the skin temperature change and the intra-articular temperature change after 5 minutes and after two hours of cold air application. Finally, 5) a significant correlation r=-0.72 (p < 0.01) between the body mass index and the baseline skin temperatures was found. There was no significant correlation between the body mass index and the temperature changes, at the skin or in the knee joint, either during or after cryotherapy (p > 0.05).