LAUSR

We read the article by Mukartihal et al. [1] regarding the temporal changes in sleep quality and knee function following primary total knee arthroplasty (TKA) with great interest. The authors prospectively included a cohort of 168 patients who underwent primary TKA. They found that patients experience changes in sleep quality but report an overall improvement in knee function during the first postoperative year. Sleep quality has a moderate-to-strong correlation with knee function in the early post-operative period beyond which there is a low correlation with knee function, thereby suggesting a transient phenomenon. We would like to offer some insights into their study. First, the authors excluded patients with conditions that could impact study design adherence (psychiatric disorders and history of alcohol abuse). This is commendable. But other factors that can lead to addiction should also be noted, such as smoking. Previous studies revealed that smoking increased the rate of complication, early revision, and mortality for patients who underwent total joint arthroplasty (TJA) [2, 3]. Strategies to help patients quit smoking before TJA are routine practice. But only part of them remained abstinent from smoking after the surgery [4]. Many studies have revealed that those who smoke cigarettes are more likely to experience poor sleep quality than those who do not smoke [5]. We recommend authors describe the smoking information of the patients to eliminate this potential confounder. Second, as the authors emphasized, pain is one of the main factors that may influence post-operative sleep quality. Mathias et al. found that individuals with pain experience significant sleep disorders [6]. In this study, the postoperative pain relief included paracetamol, tramadol, and diclofenac if required. However, the authors did not specify the trigger of medications nor quantify the dose of painkillers. This was a confounding factor that was not taken into account. Third, the authors did not explain drug nor psychological intervention protocol for patients with post-operative sleep disorders. A set of pre-determined schemes should be implemented to limit this potential confounder. We appreciate the study by Mukartihal et al. in exploring the relationship between sleep quality and knee function following TKA. This is a meaningful issue, and we expect more studies investigating this topic in the future.