The How and Why of Patients’ Sleep Disorders After A Total Knee Arthroplasty (TKA)

Many individuals suffer from impaired quality of sleep after undergoing a TKA. There have been multiple studies done in the past that confirm poor sleep quality effects the outcomes of a patient’s rehabilitation including a reduced pain threshold, decline in performance, increased fatigue and emotional dysregulation. There are 8 categories of sleep disorders with 81 major disorders according to the Diagnostic Classification of Sleep and Arousal Disorders. Insomnia is the category that occurs most frequently post TKA, therefore, that will be the focus going forward.

Insomnia Definitions and Classifications

• Insomnia
  • Individuals with a primary complaint of difficulty falling asleep, difficulty staying asleep, waking up too early, or low-quality of sleep. Individuals must have this complaint despite having acceptable circumstances and opportunity to achieve a good night’s sleep.
• Primary Insomnia
  • Adjustment sleep disorder (acute insomnia)
    • Insomnia that lasts less than 3 months.
    • Brought on by an identifiable stressor such as an environmental change, depression, anxiety and/or pain after surgery
    • Typically resolves once the stressor is removed from the individual’s life
  • Insomnia due to mental disorder
    • Occurs when individual who has been previously diagnosed with anxiety or depression have an increased worry about things. Some common items that cause the mental disorder to heighten may be the act of surgery, costs of medical bills, recovery process, etc.
  • Inadequate sleep hygiene
    • Occurs when individuals partake in activities that directly affect their sleep
    • Activities may include taking too many naps, consuming caffeine close to bed time, and going to sleep/waking up at different times every day.
  • Psychophysiological insomnia
    • Occurs when individuals are overly worried about sleeping, causing them to have sleep disruptions
  • Idiopathic Insomnia
    • Insomnia that occurs since childhood with no known cause
    • Typically, chronic and relentless in nature
  • Secondary Insomnia
    • Insomnia due to medical condition
      • Individuals may develop insomnia due to medical conditions that arise such as heart failure and asthma
    • Insomnia due to drug or substance
      • Occurs when individuals are withdrawing from drugs such as analgesics and sedatives.
    • Physiological (organic) insomnia
      • Occurs when insomnia does not fit into any of the categories listed above or there isn’t enough information to classify an individual into a specific category

In the article titled: Analysis of patients’ sleep disorder after a total knee arthroplasty- A retrospective study; the authors looked at the reasons for insomnia in patients who have received a TKA. The authors analyzed data from 965 patient cases using their medical records.

The authors found that ~3/4 of the patients were classified into primary insomnias, with adjustment sleep disorder being the most common. The sleep disorders with higher prevalence are as follows: adjustment sleep disorder (43.7%), insomnia due to a mental disorder (24.1%), insomnia due to a medical condition (19.2%), inadequate sleep hygiene (6.3%). All other sleep disorders had 5% or less of patients in the classification.

The study also looked at the causes of insomnia in the patient’s following a TKA. The top 4 causes found were as follows: pain (40.1%), mental elements such as depression and anxiety (31.3%), other medical conditions such as heart failure (15%), and noise (4.4%).

Overall, individuals who described their insomnia complaint as difficulty staying asleep or low-quality of sleep had worse pain and longer stays in the hospital. These patients also had more rehabilitative deficits such as decreased active range of motion. This was compared to the individuals who described their insomnia complaint as difficulty falling asleep or waking up too early.

The physical therapists at Physical Therapy First will provide you with the highest quality of care following surgery for a total knee arthroplasty. During each session, you will be provided 1-on-1 care with your physical therapist for a full 60-minutes. Give us a call or visit the website to schedule an appointment!

Reference:

Long G, Suqin S, Hu Z, Yan Z, Huixin Y, Tianwang L, Yang Y, Zhenhu W. Analysis of patients’ sleep disorder after total knee arthroplasty-A retrospective study. J Orthop Sci. 2019 Jan;24(1):116-120. doi: 10.1016/j.jos.2018.07.019. Epub 2018 Aug 23. PMID: 30146382.