Temporal changes in sleep quality and knee function following primary total knee arthroplasty: a prospective study

Area of Science:

• Orthopedic Surgery
• Rehabilitation Medicine
• Sleep Science

Background:

• Patient-reported outcome measures (PROMs) are crucial for assessing quality of life after total knee arthroplasty (TKA).
• Limited research exists on sleep quality and knee function changes following TKA.
• Understanding these outcomes is vital for comprehensive patient care and recovery management.

Purpose of the Study:

• To evaluate sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and knee function via the Knee Society Score (KSS) in primary TKA patients.
• To determine the correlation between sleep quality and knee function during the first post-operative year after TKA.
• To identify factors influencing sleep quality post-TKA.

Main Methods:

• A cohort of 168 primary unilateral TKA patients (cemented, posterior-stabilised implant, no patella resurfacing) were assessed.
• Global PSQI and KSS were recorded pre-operatively, weekly for six weeks, and at one year post-surgery.
• Demographic data, Body Mass Index (BMI), and Charlson Comorbidity Index (CCI) were collected pre-operatively.

Main Results:

• Pre-operative PSQI scores significantly worsened in the first six weeks post-TKA, then improved by the one-year mark (p < 0.001).
• Knee Society Score (KSS) demonstrated significant improvement from pre-operation to six weeks and one year (p < 0.001).
• A moderate to strong correlation was observed between pre-operative PSQI and early post-operative KSS (r=0.47, p<0.001), diminishing by one year (r=0.10, p=0.19). Age, CCI, and pre-operative range of motion predicted PSQI.

Conclusions:

• Total knee arthroplasty patients experience transient sleep quality changes alongside improving knee function in the first post-operative year.
• The correlation between sleep quality and knee function is strongest in the early post-operative phase, suggesting a temporary relationship.
• Patients should be counseled on potential post-TKA sleep variations and reassured about the transient nature of these changes.