Knee osteoarthritis is a common cause of severe pain and functional limitation. Total knee arthroplasty is an effective procedure to relieve pain, restore knee function, and improve quality of life for patients with end stage knee arthritis. The aim of this study was to investigate the inflammatory process in patients with primary knee osteoarthritis before surgery and in subsequent periods following total knee arthroplasty. A prospective study of 49 patients undergoing primary total knee replacements was conducted. The patients were evaluated by monitoring serum interleukin-6 (IL-6), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), knee skin temperature, and clinical status. Measurements were carried out preoperatively and postoperatively on day one and at two, six, 14, and 26 weeks during follow-up review in the knee clinic. The serum IL-6 and CRP were elevated on the first postoperative day but fell to preoperative values at two weeks postoperatively. Both returned to within the normal range by six weeks postoperatively. In addition, the postoperative ESR showed a slow rise with a peak two weeks after surgery and returned to the preoperative level at 26 weeks postoperatively. The difference in skin temperature between operated and contralateral knees had a mean value of +4.5°C at two weeks. The mean value decreased to +3.5°C at six weeks, +2.5°C at 14 weeks, and +1.0°C at 26 weeks. The difference in skin temperature decreased gradually and eventually there was no statistically significant difference at 26 weeks after surgery. A sustained elevation in serum IL-6, CRP, ESR, and skin temperature must raise the concern of early complication and may suggest the development of postoperative complication such as haematoma and/or infection.

ABSTRACT. Osteoarthritis is a chronic progressive degenerative joint disease characterized by age-related regressive change in articular cartilage. A single nucleotide polymorphism has been described at position -174 of the interleukin-6 (IL-6) promoter region, leading to three possible genotypes, GG, GC, and CC. We investigated a possible association of the IL-6 -174G/C gene polymorphism with knee osteoarthritis in a Thai population. Genotype distributions and allelic frequencies of the IL-6 -174G/C polymorphism were investigated in 115 knee osteoarthritis patients and 100 healthy controls. Genotyping was performed using PCR-RFLP. The genotype distribution of IL-6 was 79 GG, 36 GC, 0 CC in knee osteoarthritis patients and 88 GG, 12 GC, 0 CC in controls. The frequency of the GC genotype in subjects with knee osteoarthritis was higher than in controls (P < 0.001). Logistic regression analysis showed Association of IL-6 -174G/C polymorphism with knee OA that the GC genotype was independently associated with increased risk of knee osteoarthritis (odds ratio = 3.3, 95% confidence interval = 1.6-6.9, P = 0.001). These findings suggest that the -174G/C polymorphism of the IL-6 gene promoter plays a role in the pathogenesis of knee osteoarthritis.

Background: Demineralized bone matrix (DBM) is extensively used in orthopedic, periodontal, and maxillofacial application and investigated as a material to induce new bone formation. Small intestinal submucosa (SIS) derived from the submucosa layer of porcine intestine has widely utilized as biomaterial with minimum immune response. Objectives: Determine the osteoinductive potential of SIS, DBM, SIS/DBM composites in the in vitro cell culture and in vivo animal bioassays for bone tissue engineering. Materials and methods: Human periosteal (HPO) cells were treated in the absence or presence SIS, DBM, and SIS/DBM. Cell proliferation was examined by direct cell counting. Osteoblast differentiation of the HPO cells was analyzed with alkaline phosphatase activity assay. The Wistar rat muscle implant model was used to evaluate the osteoinductive potential of SIS, DBM, and SIS/DBM composites. Results: HPO cells could differentiate along osteogenic lineage when treated with either DBM or SIS/DBM. SIS/ DBM had a tendency to promote more cellular proliferation and osteoblast differentiation than the other treatments. In Wistar rat bioassay, SIS showed no new bone formation and the implants were surrounded by fibrous tissues. DBM demonstrated new bone formation along the edge of old DBM particles. SIS/DBM composite exhibited high osteoinductivity, and the residual SIS/DBM was surrounded by osteoid-like matrix and newly formed bone. Conclusion: DBM and SIS/DBM composites could retain their osteoinductive capability. SIS/DBM scaffolds may provide an alternative approach for bone tissue engineering.

We regret that the value of serum CRP was reported incorrectly. Serum CRP levels were reported incorrectly to be 10 times higher than their true value. The value of serum CRP in osteoarthritis patients following total knee arthroplasty should have been reported in milligrams per litre (mg/l), instead of milligrams per decilitre (mg/dl) for the whole article. The authors apologise for this error.The online version of the original article can be found at http://dx.doi.