Abstract
Total knee arthroplasty (TKA) is the final treatment for knee osteoarthritis, and 15–30% of patients show little or no improvement. This high percentage is related to aspects of the surgical technique, the selected implant, and specific patient characteristics. The aim of this study was to analyze whether there are differences in quality of life (QoL) and functional capacity among patients undergoing TKA with conventional implants compared to those treated with hypoallergenic oxinium implants. A pragmatic clinical study was carried out that included patients who underwent TKA between January 2013 and December 2015. During this period, 245 knees in 228 patients were treated. Eleven patients were excluded, leaving a sample of 161 conventionally treated knees, 72 knees treated with hypoallergenic implants, and one patient who received both implant types. In all patients, QoL and functional capacity were measured with the WOMAC index, the SF-12 questionnaire, and the Euro-Qol-5D L-VAS. We also assessed the psychological distress of each patient and related the findings to the functional results. The differences in QoL were tested using ANCOVA and propensity score matching (PSM) models adjusted for sex, age, weight, psychiatric history and associated complications. Patients who underwent TKA using conventional prostheses had significantly better scores on the total WOMAC index and in the pain domain (p < 0.05) than those who received hypoallergenic prostheses, but no significant differences were observed for the other domains in the ANCOVA. In contrast, with the PSM, we also found statistically significant differences in the difficulty domain of the WOMAC. Significant differences were found for the SF-12 mental health questionnaire results (p = 0.038), but the same did not occur for the physical health domain in the ANCOVA and PSM. We also found statistically significant differences in the Euro-Qol-5D index results (p = 0.041), but not in the VAS scale scores for the same questionnaire in the ANCOVA, and we did not find significant differences in either with the PSM. Patients with metal allergies and those who present psychological distress had WOMAC, SF-12, and Euro-Qol-5D results that were statistically significantly worse than those of patients who received conventional implants. Patients who underwent hypoallergic TKA had lower scores on the QoL and functional capacity scales than patients who received conventional Cr–Co implants. Additionally, patients with psychological distress had worse results on the questionnaires, and those with a metal allergy had even lower scores; the differences were statistically significant.
Highlights
Osteoarthrosis of the knee is a progressive and complex degenerative joint disease that produces chronic pain, reduces mobility, and influences quality of life and work capacity, as well as psychosocial interaction [1,2]
Hallab et al [13] have observed that skin patch tests are highly subjective, not standardized, limited to skin tissues rather than deep, and perhaps most importantly, an assessment of an exposure mechanism in which Langerhans cells initiate a hypersensitivity reaction, which differs from macrophages or a lymphocyte-mediated response that occurs in the periprosthetic environment
The scores on the WOMAC total and pain scales were significantly higher, and the mental and physical components of the Short Form-12 Health Questionnaire (SF-12) and the Euro-Qol-5D index, and the VAS were significantly lower among the patients who received hypoallergenic prostheses (p < 0.05)
Summary
Osteoarthrosis of the knee is a progressive and complex degenerative joint disease that produces chronic pain, reduces mobility, and influences quality of life and work capacity, as well as psychosocial interaction [1,2]. Total knee arthroplasty (TKA) is the final treatment for knee osteoarthritis, reducing pain and improving the quality of life of patients [3,4,5,6,7], but between 15% and 30% of patients who undergo TKA have little or no improvement [6,7,8] This high percentage involves factors related to the surgical technique [5,8], patient characteristics [1,2,9], and the selected implant [2,10]. We consider whether suffering from psychological distress influences the results in patients who are allergic and not allergic to metals
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