Page 51 - The value of total hip and knee arthroplasties for patients

Outcome of total hip arthroplasty, but not of total knee arthroplasty, is related to the preoperative radiographic severity of osteoarthritis
Overall, our results are in line with the literature, with the majority of studies
concluding that more severe radiographic OA preoperatively is associated with
better outcomes inTHA orTKA.3-5 ConcerningTHA specifically, similar to the present
study,Valdes et al.3 reported greater improvements in pain 3 years after surgery in
patients with severe radiographic OA preoperatively. Greater improvements in the
SF subscale and summary scale scores were seen in patients with higher KL scores 3 in a study by Keurentjes et al.5, but the differences were not statisticaly significant.
RegardingTKA, our study did not show any statistically significant differences between the outcomes in patients with different grades of radiographic severity, although—as in the study by Cushnaghan et al.2—greater improvements were generally seen in patients with higher KL grades. In contrast,Valdes et al.3 and Keurentjes et al.5 found statistically significantly better outcomes in TKA patients with severe radiographic OA, and similar results were seen in some of the analyses in the study by Dowsey et al.4 Comparisons with the literature are, however, hampered by the large diversity in study designs and analyses.
It is difficult to draw conclusions about the clinical relevance of the results of our study and of previous ones. Firstly, there are several factors associated with worse outcomes after THA/TKA, such as older age, female sex, obesity, worse general health, involvement of other joints, and a lower level of education.13, 14 Only from large, prospective studies using a standardized set of preoperative characteristics and outcome assessments done at fixed time points can true prediction models including all potentially relevant determinants be derived, which afterwards need to be validated in multiple settings and countries. However, we can interpret the absolute change scores as observed in the different groups according to radiographic severity. A recent systematic review by Keurentjes et al.15 found that overall minimally clinically important differences (MICDs) in HRQoL in THA/TKA have limited precision and are not validated using external criteria.The study which is most comparable to our study is that from Clement et al.16 In that study, the MCID in OKS for the difference between preoperatively and 1 year postoperatively was 15.5 (95% CI: 14.7–16.4). In our study, generally patients in both the mild and severe OA groups achieved this improvement, indicating that the clinical relevance of a statistically significant difference may be limited.
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