Objective To investigate the diagnostic value of knee skin temperature and serum soluble intercellular adhesion molecule-1 (sICAM-1) level in peri-prosthetic infection after total knee arthroplasty (TKA).Methods Thirty patients (11 males and 19 females,aged 59.3±9.5 years old) underwent primary TKA during November 2012 and October 2015.Ten patients with peri-prosthetic infection (3 males and 7 females,aged 60.9±8.2 years old) underwent two-stage revision TKA from November 2012 to October 2015.The interleukin-6 (IL-6),C-reactive protein (CRP),erythrocyte sedimentation rate (ESR),sICAM-1 in serum and the skin temperature in knee joint were recorded preoperatively (revision patients on diagnosis),at days 1,7 and at 1,3,6,12 months post-operatively.Results All of the 40 patients were followed up for 12 months.The serum CRP,IL-6 and ESR levels in the primary TKA group were normal preoperatively and increased after operation,reaching their peaks at 1-7 days postoperatively.These indexes then returned slowly to the normal levels within 3 months.The serum sICAM-1 level in the primary TKA group did not change significantly during the follow up.The serum levels of CRP,IL-6,ESR,and sICAM-1 in the revision group were significantly higher than that in the primary TKA group preoperatively (P＜0.05),IL-6,CRP,ESR returned slowly to the normal levels within 3 months after the second-stage revision,while the level of sICAM-1 returned to normal within 3 months after the first-stage revision.During whole follow-up after the second-stage revision,the level of sICAM-1 didn't change significantly.The preoperative mean differential temperature (MDT) in the primary TKA group was 0.73±0.62 ℃ preoperatively and elevated to 4.37±1.06 ℃ at 7 days postoperatively,which returned to the baseline within 6 months after primary TKA.The preoperative MDT in the revision group was 5.03±0.81 ℃,which was significantly higher than that in the primary TKA group (P＜0.05).The MDT returned to the normal level within 6 months after the second-stage revision TKA.Conclusion The change of MDT is in accordance with serum CRP,IL-6,and ESR,which together may predict the occurrence of infection.Serum sICAM-1 level may also be valuable in the diagnosis of peri-prosthetic infection.

BACKGROUNDTotal knee arthroplasty (TKA) is a successful and frequently performed procedure in orthopedic surgery. The diagnosis of peri-prosthetic joint infection following TKA remains challenging. The present study estimated the usefulness of knee skin temperature (measured by infrared thermography) and serum soluble intercellular adhesion molecule-1 (sICAM-1) in the diagnosis of post-operative knee peri-prosthetic infection.

METHODSPatients were divided into three groups: 21 patients undergoing uncomplicated TKAs, seven with prosthesis infection, and three undergoing TKA revisions. The serum levels of interleukin-6 (IL-6), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and sICAM-1 as well as the local knee skin temperature were measured pre-operatively and on Days 1 and 7 and at 1, 3, and 6 months post-operatively in Groups 1 and 3. The same parameters were measured in Group 2 at the time of prosthesis infection diagnosis.

RESULTSIn Group 1, the levels of IL-6, CRP, ESR, and knee skin temperature were significantly elevated post-operatively, but returned to baseline levels within 6 months. The sICAM-1 levels were not significantly different. The mean differential temperature (MDT) and levels of siCAM-1, IL-6, CRP, and ESR differed significantly between Groups 1 and 2. The MDT had returned to normal in Group 3 by 6 months post-operatively.

CONCLUSIONSElevations in IL-6, CRP, ESR, and MDT in patients undergoing TKA could be a normal response to surgical trauma, but sustained elevations may be indicative of complications. The knee skin temperature and sICAM-1 may be used as indicators in the diagnosis of knee prosthesis infection following TKA.

Adult ; Aged ; Arthroplasty, Replacement, Knee ; adverse effects ; Blood Sedimentation ; C-Reactive Protein ; metabolism ; Female ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; Interleukin-6 ; blood ; Knee Joint ; immunology ; surgery ; Male ; Middle Aged ; Prospective Studies ; Skin Temperature ; physiology ; Thermography ; methods