Study Of The Value Of Infrared Thermography In Diagnosing Osteoarthritis(OA) Of Knee

[Objective]observe the thermogram formation characteristics of articular genus of OA of knee patients and the law on temperature changes of their knee skin surface, understand the diagnosis value for OA of Infrared thermography, and explore into the relation between the formation of articular genu OA and blood flow condition.[Methods]choose 30 people suffering from primary OA of knee on single knee, and then take their trouble knees as the test group while healthy one as the control group. At the constant room temperature of 22-27℃and before and after pressurizing with tourniquet, use HR-2 series of medical infrared cameras to conduct infrared thermographical scanning of every group of articular genus and every front and flank sides separately. Then thermograms are worked out from computers and the Thermogram formation characteristics of OA of knee observed. Then computers are used to measure the average skin surface temperature of the front side, inner side (tibial), outer side (fibula side) of every group of articular genu (the rear side skin surface temperature shall be excluded since it is highly subject to popliteal blood current to cause big analytical error). Then analyze the temperature changes of their knee skin surface before and after pressurizing articular genus and explore into the relation between the formation of OA of knee and blood flow condition.[Results]1.The infrared thermograms of OA of knee presents rising temperature centered on articular genu while higher temperature with pressure increased.2.Of the temperatures of the three sides of normal articular genu(front side: 23.72±0.38, tibial:24.14±0.34, fibula side:24.22±0.37),that of the front side is the lowest (P is less than 0.05), and there is no remarkable difference between those of the tibial and fibula-side (P=0.337). Compared with normal knees, the above three temperatures of trouble knees(front side: 24.09±0.70, tibial: 24.59±0.56, fibula side: 24.70±0.63) are also the lowest for the front side (P is less than 0.05),and there is no remarkable difference between those of the tibial and fibula-side (P=0.279).3.The three sides of temperatures of OA articular genu rise by about 0.3～1.0℃, presenting remarkable difference from those of healthy knees. 4.There is no remarkable difference among all side temperatures of trouble knees in terms of the sex and left or right side of patients (P is always over 0.05). the temperatures are connected with ache, swelling and malformation, so all the temperatures of trouble knees with ache, swelling and malformation are relatively high and have the P of below 0.05, except for the fibula-side temperatures with swelling and malformation (P is respectively 0.083,0.056), in light of the error due to the small number of swelling and malformation cases (there are only 6 knees with swelling and 5 with malformation among the said 30 knees).5.For the articular genu with OA, X-ray images show the side stenosis temperature of the patellofemoral joint, articulatio wall femorotibialis, and articulatio lateral femorotibialis, higher than the corresponding temperature of the articular genu without stenosis (P is always below 0.05).6.After pressurizing with tourniquet, the masculine rate of trouble knees aching is respectively 23.33% and 46.67%, and 0.10>P>0.05 is obtained by comparing them. Take 0.10 as a, and there is remarkable difference, which shows that pressurizing with tourniquet can make trouble knees ache.7.After pressurizing with tourniquet, all the side temperatures of healthy knees rise by about 0..2～0.4℃. Compared with the temperatures before pressurizing, the difference is significantly remarkable (P is always below 0.05). It shows that the stagnant blood due to pressurizing with tourniquet can raise knee temperature..8.After pressurizing with tourniquet, all the side temperatures of the knees of articular genu OA patients rise. Compared with the temperatures before pressurizing, the difference is significantly remarkable (P is always below 0.05). It shows that the stagnant blood due to pressurizing with tourniquet can raise knee temperature, too. Take as covariates the same side temperatures of normal and trouble knees before pressurizing while as dependent variables those after pressurizing to carry out covariance analysis (for three independent parts of front side, tibial and fibula-side) and we can P below 0.05. It shows that excluding the influence from temperature before pressurizing, all the side temperatures of trouble knees rise to a greater extent than those of normal knees, which demonstrates that the stagnant blood due to pressurizing with tourniquet have a greater impact on trouble knees.[Conclusion]infrared thermograms can sensitively measure the changes in the temperature and thermograms and thus have a certain diagnostic value for the articular genu with OA; the temperature changes of trouble knees aren't related to sex or aching part while closely related to whether there is ache, swellinm, malformation and joint space stenosis on X-ray images or not; the skin surface temperatures of trouble and normal knees rise as a result of pressurizing with tourniquet with a greater influence on trouble knees, which demonstrates that there may be close relation between the formation of articular genu OA and blood flow condition.