Prospective cohort study, Level II.

Background Failure after total knee arthroplasty (TKA) may be related to emerging technologies, surgical techniques, and changing patient demographics. Over the past decade, TKA use in Korea has increased substantially, and demographic trends have diverged from those of Western countries, but failure mechanisms in Korea have not been well studied.Questions/purposes We determined the causes of failure after TKA, the risk factors for failure, and the trends in revision TKAs in Korea over the last 5 years. The Knee Society, patient demographics, information on index and revision of TKAs, and indications for index TKA. The influences of patient demographics and indications for index TKA on the risk of TKA failure were evaluated using multivariate regression analysis. The trends in revision procedures and demographic features of the patients undergoing revision TKA over the last 5 years were assessed. Results The most common cumulative cause of TKA failure was infection (38%) followed by loosening (33%), wear (13%), instability (7%), and stiffness (3%). However, the incidence of infections has declined over the past 5 years, whereas that of loosening has increased and exceeds that of infection in the more recent 3 years. Young age (odds ratio [OR] per 10 years of age increase, 0.41; 95% confidence interval [CI], 0.37-0.49) and male sex (OR, 1.88; 95% CI, 1.42-2.49) were associated with an increased risk of failure. The percentage of revision TKAs in all primary and revision TKAs remained at approximately 3%, but the annual numbers of revision TKAs in the more recent 3 years increased from that of 2008 by more than 23%. Conclusions Despite a recent remarkable increase in TKA use and differences in demographic features, the causes and risk factors for failures in Korea were similar to

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We hypothesized that changes in patellar thickness following patellar resurfacing affect patellar tilt in total knee arthroplasty (TKA) patients. The study enrolled 272 TKAs and categorized them into four groups according to change in patellar thickness: (A) thinner by 1 mm or more, (B) equal or thinner by less than 1 mm, (C) thicker by 1 mm or less, and (D) thicker by more than 1 mm. Patellar tilt angle was measured postoperatively using Merchant radiography. There were no significant differences in postoperative patellar tilt among groups A, B, and C (n.s). However, the postoperative patellar tilting angle of group D was significantly higher than that of all other groups (P < 0.05). Postoperative patellar tilt increased when the postoperative patella was >1 mm thicker than the preoperative patella.

Our results suggest that IL-32gamma stimulation can induce the production of IL-6 and IL-8 from RA FLS via Erk1/2 activation.

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Three hundred and sixty-four low contact stress (LCS) total knee arthroplasties that could be followed up for more than 5 years were clinically and radiographically analyzed. The median postoperative Hospital for Special Surgery score improved from 56 (range 32-77) to 91 (range 64-100) points, but median range of motion did not change from 120° (range 50°-135°) to 120° (range 85°-135°). Complications occurred in 16 cases (4%), and included postoperative polyethylene dislocation and intraoperative tibial condylar fracture, while five knees (1%) required revision surgery due to mechanical reasons. The overall prosthesis survival rate was 91% at 12 years. Although the LCS mobile-bearing knee system has theoretical advantages in terms of wear and loosening, the problem of polyethylene dislocation, intraoperative tibial fracture, and radiolucent lines should be solved for long survival. The clinical relevance of this study is that the LCS system provided good clinical and survival results.