Preoperative sleep quality affects postoperative pain and function after total joint arthroplasty: a prospective cohort study

From March 2017 to March 2018, patients who were scheduled to undergo primary unilateral TJA were eligible for study enrollment. Patients were excluded based on the following criteria: primary sleep disorders (insomnia, apnea, and restless legs), mental disorders (depression, anxiety), chronic uncontrolled medical illnesses beyond their joint disease (preoperative hepatic or renal dysfunction and serious cardiac and/or cerebrovascular comorbidities), planned revision surgery, bilateral arthroplasty, and refusal to participate.

All total hip and knee replacement surgeries were performed under general anesthesia by two orthopedic surgeons. The patients were sent to the inpatient orthopedic unit where they spent 3–4 days before being discharged to continue their recovery at home after the surgery. The lights in the inpatient unit were dimmed between 10 pm and 6 am, and patient doors were closed. Six beds were placed in each inpatient unit. No attempt was made to manage the sleep quality for this group of patients.

Pain management [16] was used for pain control in all patients according to the standard practice at our institution, as described by Lei et al. [17]. Multimodal oral analgesic drugs (diclofenac 50 mg q 12 h, Novartis Biomedical Research Co., Ltd., Switzerland, and pregabalin 75 mg q 8 h, Pfizer Pharmaceuticals Co., Ltd., USA) were administered for preemptive analgesia 1 day before surgery. This analgesic regimen was repeated when patients resumed postoperative oral intake. When patients reported pain greater than 4 on a 0–10 visual analog scale (VAS), oral oxycodone (10 mg q 8 h) was utilized. An intramuscular injection of parecoxib (40 mg) was used if a patient claimed severe pain greater than 6 on the VAS [17].

Prophylaxis against venous thromboembolism was administered following the standard practice at our institution [18, 19]. An examination of the clinical symptoms of deep vein thrombosis (DVT) in all patients was conducted according to the standard practice at our institution [18]. During hospitalization, the patients were examined daily for any clinical symptoms of DVT. Ultrasound examinations were also performed routinely at specific time points (preoperatively, at discharge, and at the 2-week and 3-month follow-ups). If a patient was symptomatic, an ultrasound examination was performed immediately. A contrast-enhanced chest spiral computed tomography was performed immediately for any clinical signs of pulmonary embolism (PE) [18, 20]. In addition, other complications including superficial infection, hematoma, and wound secretion were also diagnosed according to the standardized list and definitions [21, 22].

Sleep quality was evaluated by 2 separate assessments (ZY. L. and D. W.). Sleep quality can be measured by using three subjective methods. The patients were required to complete the Pittsburgh Sleep Quality Index (PSQI), a self-rated questionnaire that assesses sleep quality and disturbances over a 1-month time interval prior to admission [9, 23]. Nineteen individual items generate 7 “component” scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The sum of scores for these 7 components yields 1 global score, with a maximum score of 21. A higher score indicates worse sleep dysfunction, and a score greater than 5 indicates poor sleep quality [8]. Daytime sleepiness assessment was assessed using the Epworth Sleepiness Scale (ESS) [24]. The ESS is a standardized, validated questionnaire for assessing daytime sleepiness. It contains 8 questions that ask respondents to assess on a 4-point scale the typical opportunities for them to fall asleep or doze off during various daily activities. The Epworth sleep scale score ranged from 0 to 24 (sum of 8 scores, 0–3), with higher scores indicating a greater propensity for daytime sleepiness. In general, ESS scores can be interpreted as follows: 0–5 lower normal daytime sleepiness, 6–10 higher normal daytime sleepiness, 11–12 mild excessive daytime sleepiness, 13–15 moderate excessive daytime sleepiness, and 16–24 severe excessive daytime sleepiness [25]. Finally, we used a ten-point scale to measure the patient’s sleep quality, defined on a scale from 0 (extremely poor sleep quality) to 10 (extremely good sleep quality). The higher the score was, the better the quality of sleep.

The primary study outcome measured was the VAS pain score, defined on a scale from 0 (no pain) to 10 (severe pain). In particular, we recorded active and nocturnal VAS pain scores, respectively, which can provide additional useful and detailed information about patients’ pain sensations before and after surgery. Night pain was assessed in the morning by nursing staff. In addition, the consumption of analgesic rescue drugs (oxycodone and parecoxib) was recorded, and the doses of oxycodone were expressed in morphine milligram equivalents. We also measured functional parameters, including ROM, Knee Society Score (KSS), and Harris hip score (HHS). In addition, all patients were required to complete a 10-point satisfaction questionnaire upon discharge to assess their satisfaction level, defined on a scale from 0 (very dissatisfied) to 10 (extremely satisfied) [26, 27], and the postoperative LOS was recorded. At our institution, patients undergoing arthroplasty are prospectively followed up at 2 weeks and 12 weeks to record their clinical outcomes. For enrolled patients who did not return to their postoperative outpatient appointments, the results were obtained by telephone at the appropriate follow-up points. All complications were also recorded during the first 3 postoperative months.

Distributions of demographic data, baseline data, and primary and secondary outcomes were assessed using measures of central tendency (mean, standard deviation) for quantitative variables and with percentages for qualitative variables. Pearson correlations were performed between the PSQI, ESS, and sleep quality scores with the VAS scores, dose of analgesic rescue drugs, ROM, HHS, KSS, satisfaction score, and LOS. Spearman correlations were also performed between sleep parameters and the number of patients requiring analgesic rescue drugs. An independent sample t test was used to compare patients with and without complications against their PSQI, ESS, and sleep quality measures. All data analyses were performed using SPSS for Windows, Version 19.0 (SPSS Inc., Chicago, IL, USA). Significance was set at P < 0.05.

From March 2017 to March 2018, 691 and 724 patients were scheduled to undergo total knee and hip replacement, respectively, at our institution. Among these patients, 191 and 187 were ineligible, while 29 and 14 refuse to participate. Hence, 471 and 523 patients were enrolled in the cohort. No patients were lost or excluded during the follow-up.

The mean patient age (and standard deviation) for those that underwent TKA and THA was 64.28 ± 9.68 and 54.85 ± 13.20 years, respectively. A total of 114 (24.2%) and 289 (55.2%) patients were men among the TKA and THA patients, respectively. The mean patient body mass index (BMI) was 25.81 ± 3.57 and 24.10 ± 3.97 kg/m², respectively (Table 1). Preoperative sleep parameters (i.e., PSQI, ESS, sleep quality scores) were 10.27 ± 3.77, 7.70 ± 2.31, and 7.86 ± 1.39 for TKA patients, and 10.11 ± 3.56, 7.36 ± 2.41, and 8.19 ± 3.72 for the THA patients (Table 1).

Postoperative pain and clinical outcomes are reported in Table 2. Notably, the nocturnal and active pain scores in the TKA group were 3.14 ± 1.41 and 4.99 ± 1.73 on postoperative day (POD) 1, and the pain was gradually relieved 3 days, 14 days, and 3 months after surgery. In addition, the pain scores in the THA group showed a similar trend than the TKA group. The average ROM was 98.11 ± 11.29 and 97.69 ± 7.47 for the TKA and THA groups on POD1 and 110.20 ± 5.96 and 110.13 ± 6.07 on POD3, respectively (Table 2). The number of patients requiring parecoxib and oxycodone (morphine milligram equivalents) is shown in Table 2. No PE or DVT was observed in any group (Table 3). The average satisfaction level of the two groups after joint replacement reached 8.9 points. The average postoperative LOS in the knee replacement group was 4.21 ± 2.23 days, while that in the hip replacement group was 4.05 ± 2.51 days (Table 3).

The correlations between the sleep parameters and postoperative pain, ROM, postoperative LOS, and clinical function outcomes after TKA are presented in Table 4. Before TKA, the PSQI scores were significantly correlated with increased nocturnal (r = 0.123, P = 0.008) and active (r = 0.118, P = 0.010) pain scores. In addition, the PSQI scores were significantly correlated with nocturnal (r = 0.098, P = 0.034) and active (r = 0.127, P = 0.006) pain scores and ROM (r = − 0.149, P = 0.001) and KSS (r = − 0.209, P = 0.001) on POD1. Similarly, sleep quality was significantly correlated with active pain scores (r = − 0.099, P = 0.031) and ROM (r = 0.129, P = 0.005) on POD1. There was also a significant correlation between the PSQI and active pain scores measures on POD3 (r = 0.119, P = 0.009). However, no significant correlations were noted between the sleep parameters and functional outcomes on POD14. In addition, a negative correlation between the active pain scores and ESS scores was noted on POM3 (r = − 0.091, P = 0.049).

The correlations between the sleep parameters and postoperative pain, ROM, postoperative LOS, and clinical function outcomes after THA are presented in Table 4. The PSQI scores were significantly correlated with increased nocturnal (r = 0.111, P = 0.011) and active (r = 0.120, P = 0.006) pain scores and the HHS (r = − 0.134, P = 0.002) before THA. Similarly, the ESS (r = − 0.134, P = 0.002) and sleep quantity (r = − 0.098, P = 0.025) measures were also noted to be significantly correlated with the HHS before THA. In addition, the PSQI scores significantly correlated with the pain scores on POD1 and POD3.

The correlations between sleep parameters and analgesic use are documented in Table 5. The average doses of parecoxib after knee arthroplasty were significantly correlated with the PSQI scores (r = 0.114, P = 0.013). In addition, the number of patients requiring parecoxib was also correlated with the PSQI scores in the THA group (r = 0.086, P = 0.048). However, no significant correlations were noted between the other sleep parameters and consumption of the analgesics.

Moreover, significant correlations were noted between the sleep parameters and postoperative LOS, which indicated that increased postoperative LOS correlated with poor sleep quality (Table 4). However, there were no significant correlations between sleep parameters and perioperative complications, and postoperative satisfaction levels were also not significantly correlated with sleep parameters (Table 6).