Purpose The objective of this study was to evaluate the in vivo wear resistance of cobalt-chromium femoral components coated with titanium nitride (TiN). Our null hypothesis was that the surface damage and the thickness of the TiN coating do not correlate with the time in vivo.Methods Twenty-five TiN-coated bicondylar femoral retrievals with a mean implantation period of 30.7 ± 11.7 months were subjected to an objective surface damage analysis with a semi-quantitative assessment method. A visual examination of scratches, indentations, notches and coating breakthroughs of the surfaces was performed. The roughness and the coating thickness of the TiN coating were evaluated in the main articulation regions.ResultsNarrow scratches and indentations in the range of low flexion angles on the retrieval surfaces were the most common modes of damage. There was no evidence of delamination on the articulation surface but rather at the bottom of isolated severe indentations or notches. An analysis of three retrievals revealed a coating breakthrough in the patellofemoral joint region, resulting from patella maltracking and a dislocation. The arithmetical mean roughness of the TiN surface slightly increased with the implantation period. In contrast, the maximum peak height of the roughness profile was reduced at the condyles of the retrieved components in comparison with new, unused surfaces. No significant association between the coating thickness and implantation period was determined. Moreover, the measured values were retained in the range of the initial coating thickness even after several years of in vivo service.ConclusionsAs was demonstrated by the results of this study, the surface damage to the TiN coating did not deteriorate with the implantation period. The calculated damage scores and the measured coating thickness in particular both confirmed that the TiN coating provides low wear rates. Our findings support the use of wear-resistant TiN-coated components in total knee arthroplasty with the objective of reducing the risk of aseptic loosening. However, in terms of TiN-coated femoral components, particular attention should be paid to a correct patellar tracking in order to avoid wear propagation at the implant.

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A variety of different bearing surfaces have been used to avoid osteolysis following hip replacement. We report a retrospective review of medium-term results of a modern ceramic-ceramic bearing (Biolox, CeramTec, Plochingen, Germany) and uncemented components (Alpha Cera Fit Alphanorm, Lassnitzhohe, Austria) in 107 hip arthroplasties. The clinical outcome based on serial radiographs and scoring was assessed with a minimum follow-up of 7 years (mean, 7, 6 years; range, 7, 1-8, 3 years). The average age of the patients at surgery was 64, 6 + 11, 7 years (range: 21-88 years). The mean Harris hip score was 90, 4 (range, 84, 7-99, 2). Three patients with an extra long femoral neck experienced fracture of the ceramic femoral head, resulting in cessation of use of this combination. Radiological evaluation did not reveal any signs of lysis or loosening. Massive heterotopic ossification was seen in three patients. Medium-term follow-up showed excellent clinical and radiological results. Continued follow-up will be required to determine if this ceramic-on-ceramic bearing is associated with extended survivorship.

Background Spontaneous recurrent hemorrhage after arthroplasty of the hip or knee is a rare condition. In patients who do not have coagulopathy, the likeliest etiology for hemarthrosis is hypertrophic vascular synovium.

We determined the density of natural killer (NK) cells in frozen sections of malignant melanoma (nine cases), squamous cell carcinoma (six cases) and non-neoplastic tonsil (five cases) by immunohistological and stereological methods. The mean density of NK cells in malignant melanoma (5.0 +/- 1.5 X 10(3)/mm3) and in squamous cell carcinoma (5.1 +/- 2.7 X 10(3)/mm3) was significantly lower than in germinal centres of normal human tonsils (5.0 +/- 0.8 X 10(4)/mm3). The NK cell/tumour cell ratio (0.03 +/- 0.015 in malignant melanoma and 0.02 +/- 0.015 in squamous cell carcinoma) is 10(2)-10(4) times lower than that commonly used for in vitro assays. The possible role of NK cells in malignant skin tumours should be viewed with caution.

Background: The impact of titanium nitride (TiN) coating on implant components is controversial. TiN coating is proposed as having superior biomechanical properties compared to conventional cobalt-chromium (CoCr) alloy. This study compared long-term clinical data as well as meteoro-sensitivity in patients who underwent total knee arthroplasty (TKA), with either CoCr alloy or TiN coating. Methods: In this retrospective observational study, the clinically approved cemented “low contact stress” (LCS) TKA with conventional CoCr coating, was compared to un-cemented TiN-coated “advanced coated system” (ACS) TKA. Propensity score matching identified comparable patients based on their characteristics in a one-to-one ratio using the nearest-neighbor method. The final cohort comprised 260 knees in each cohort, with a mean follow-up of 10.1 ± 1.0 years for ACS patients and 14.9 ± 3.0 years for the LCS group. Physical examinations, meteoro-sensitivity, and knee scoring were assessed. Results: The clinical and functional Knee Society Score (KSS) (82.6 vs. 70.8; p < 0.001 and 61.9 vs. 71.1; p = 0.011), the postoperative Visual Analogue Scale (VAS) (2.9 vs. 1.4; p = 0.002), and the postoperative Tegner Score (2.6 vs. 2.2; p = 0.001) showed significant intergroup differences. The postoperative Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) was similar (79.9 vs. 81.3; p = 0.453) between groups. Meteoro-sensitivity of the artificial joint was significantly more prevalent in the ACS patient cohort (56% vs. 23%; p < 0.001). Conclusion: This study suggests that TiN coating does not provide improved clinical outcomes in this patient cohort after a long-term follow-up. Interestingly, sensitivity to weather changes were more correlated with un-cemented ACS implants.

Introduction Smoking has been associated with numerous adverse outcomes following surgical procedures. The purpose of this study was to investigate, whether smoking status at time of surgery influences the outcome of primary TKA. Materials and methods Six hundred and eighty-one patients who underwent primary TKA between 2003 and 2006 were included in the study. Smoking status was defined as current, former, and never smoker. Complications leading to revisions were assessed until 17 years of follow-up. Functional outcome was evaluated using clinical scores: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Visual Analogue Scale (VAS) for pain, Short Form-12 Physical and Mental Component Summaries (SF-12PCS/MCS), and Knee Society Function and Knee Score (KSFS and KSKS). Results At a mean follow-up of 95 months (± 47 months), 124 complications led to revision surgery. Soft-tissue complications (OR, 2.35 [95% CI 1.08–5.11]; p = 0.032), hematoma formation (OR, 5.37 [95% CI 1.01–28.49]; p = 0.048), and restricted movement (OR, 3.51 [95% CI 1.25–9.84]; p = 0.017) were more likely to occur in current smokers than never smokers. Current smokers were more likely to score higher at KSFS (p < 0.001) and SF-12PCS (p = 0.0197) compared to never smokers. For overall revision, differences were noted. Conclusion Current smoking increases risk of soft-tissue complications and revision after primary TKA, especially due to hematoma and restricted movement. Smoking cessation programs could reduce the risk of revision surgery.

Introduction High BMI is associated with increased risk for knee osteoarthritis, ultimately necessitating total knee arthroplasty (TKA). The aim of this retrospective study was to (1) analyse the amount of postoperative long-term weight loss as reflected by BMI change in TKA patients, (2) identify factors associated with increased change in BMI, and to (3) compare changes with BMI trends of a general population. Materials and methods Overall, 298 TKA patients [198 females; mean age: 65.1 ± 7.9 years, median follow-up 8.8 (interquartile range: 5.9–10.8 years)] were included in the final evaluation and compared with an age group-matched control group from the general population regarding weight trends between 2006 and 2014. Main variable of interest in both cohorts was body mass index (BMI). Linear regression analyses were performed to assess changes in weight and BMI over time between TKA patients and the general population. Furthermore, mixed linear-effects models were constructed to analyse the potential change in BMI independent from age and gender. Results In TKA patients, a significant drop in BMI by 0.8 ± 3.2 points from postoperative to final follow-up was observed (p < 0.001), with reduction being significant independently from age (p = 0.382), gender (p = 0.310), or revision surgery (p = 0.195). In the general population, likewise a significant BMI-decrease by 0.7 ± 6.1 points was observed between 2006 and 2014, with younger people (p = 0.004) and females (p < 0.001) being more likely to reduce BMI. Yet, BMI-decrease between TKA patients and the general population over time was comparable (p = 0.734). Notably, patients with initially higher BMI were significantly more likely to lose weight postoperatively than normal-weight patients (p < 0.001). Conclusions Our results point against the notion that TKA patients lose a considerable amount of weight in comparison to the general population as soon as improved joint function and pain relief have been achieved. Thus, individualized patient education programmes should be reinforced, promoting a healthy lifestyle.