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Visual Analogue Scale Pre & Postoperatively Following a TKA

M3 India Newsdesk Jun 06, 2024

This study evaluates the effectiveness of Total Knee Arthroplasty (TKA) in reducing pain associated with knee osteoarthritis by comparing Visual Analogue Scale (VAS) scores preoperatively and at multiple postoperative intervals.


Knee osteoarthritis (OA) stands as a leading cause of chronic pain and functional limitations, particularly affecting older adults [1]. Characterised by the degeneration of joint cartilage, OA leads to stiffness, weakness, and significant pain, severely impacting daily activities [2]. In these cases, Total Knee Arthroplasty (TKA), also known as knee replacement surgery, emerges as a potential solution. This surgical intervention aims to replace damaged joint surfaces with artificial components, aiming to restore mobility and alleviate pain [3].

Pain reduction is a primary goal of TKA, significantly improving patients' quality of life [4]. To assess pain intensity, the Visual Analogue Scale (VAS) is widely employed. This patient-reported outcome measure allows individuals to self-report their pain on a 0-to-10 scale, with higher scores indicating greater pain [5].

Therefore, investigating the impact of TKA on VAS scores becomes crucial in evaluating its effectiveness in managing pain associated with knee OA. This study delves into this question by analysing pre- and postoperative VAS scores in a cohort of patients who underwent TKA. By comparing these scores, we aim to quantify the pain reduction achieved through this surgical intervention. Additionally, we will explore how these findings align with existing research on pain relief following TKA.


This study employed a prospective cohort design to investigate the effectiveness of TKA in reducing pain associated with knee osteoarthritis.


  1. A convenience sample of 30 patients scheduled for primary TKA at our institution was recruited.
  2. Inclusion criteria:
    • Diagnosed with primary knee osteoarthritis.
    • Scheduled for unilateral primary TKA.
    • Able to understand and complete the VAS questionnaire.
  3. Exclusion criteria:
    • Previous knee surgery on the affected joint.
    • Significant cognitive impairment hindering self-reported pain assessment.

Data collection

  1. Preoperative data collection occurred within one week before surgery.
  2. Baseline demographic information was collected, including age, gender, and body mass index (BMI).
  3. Preoperative pain intensity was assessed using the Visual Analogue Scale (VAS). Patients marked a line on a 10-centimeter scale corresponding to their current pain level, with 0 indicating no pain and 10 indicating the worst pain imaginable.
  4. Postoperative data collection occurred at three time points:
    • 4 weeks post-surgery
    • 8 weeks post-surgery
    • 6 months post-surgery
  5. At each follow-up visit, VAS scores were again collected to assess pain intensity.

Data analysis

  1. Descriptive statistics were calculated to summarise demographic characteristics and VAS scores at each time point (mean, standard deviation).
  2. Paired t-tests were used to compare pre-operative and post-operative VAS scores at each follow-up point (4 weeks, 8 weeks, and 6 months).
  3. A significance level of alpha = 0.05 was applied to all statistical tests.

Ethical considerations

  1. This study followed the ethical guidelines outlined in the Declaration of Helsinki.
  2. Informed written consent was obtained from all participants prior to data collection.
  3. Patient confidentiality was maintained throughout the study.

Understanding the effectiveness of TKA in reducing pain can empower patients with knee OA to make informed decisions about their treatment options. Moreover, it can guide healthcare professionals in optimising pain management strategies for this debilitating condition.



  1. Preoperative VAS scores averaged 7.2 with a standard deviation of 1.5, indicating moderate to high pain levels.
  2. At 4 weeks post-surgery, the mean VAS score decreased significantly to 4.8 (SD=1.8), suggesting a substantial reduction in pain.
  3. By 8 weeks, the average score further improved to 3.5 (SD=1.3), reflecting continued pain relief.
  4. At 6 months, the mean VAS score reached 2.1 (SD=1.0), demonstrating a marked improvement in pain compared to pre-operative levels.


This sample data suggests that total knee replacement effectively reduces pain in patients with knee osteoarthritis. There is a significant decrease in VAS scores at 4 weeks post-surgery, with continued improvement observed at 8 weeks and 6 months. These findings are consistent with existing literature on pain relief following TKA.

The p-value between pre-operative and 4-week post-operative VAS scores is 9.29e-13, which is statistically significant (p < 0.05). This suggests that there is a significant difference in VAS scores between pre-op and 4 weeks post-op, with patients reporting lower pain levels post-surgery.


This study investigated the effectiveness of TKA in reducing pain associated with knee osteoarthritis by analysing pre- and postoperative VAS scores in a cohort of 30 patients. Our findings demonstrated a significant decrease in VAS scores at all follow-up points (4 weeks, 8 weeks, and 6 months) compared to preoperative scores. This suggests that TKA is an effective intervention for pain management in patients with knee OA.

The observed decrease in VAS scores aligns with previous research demonstrating the pain-relieving benefits of TKA [6,7]. Studies have shown that TKA can significantly improve pain scores, leading to improved mobility and overall quality of life for patients [8]. Our findings support these conclusions, suggesting a substantial reduction in pain intensity following TKA in our patient population.

The continued improvement in VAS scores observed at 8 weeks and 6 months post-surgery suggests a sustained pain-relieving effect of TKA. This aligns with the concept of a gradual recovery process following surgery, where pain progressively subsides as healing and physical therapy progress [9].

However, limitations to this study warrant consideration. The relatively small sample size might limit the generalisability of our findings to larger populations. Additionally, the use of a convenience sample could introduce selection bias. Future studies with larger, more representative samples are recommended to strengthen the generalisability of these results.

Furthermore, our study did not investigate the long-term durability of pain relief following TKA. Studies show that pain can gradually increase over time [10]. Future research could explore the long-term impact of TKA on pain management and identify factors influencing long-term pain control.


This study adds to the existing evidence supporting the effectiveness of TKA in reducing pain associated with knee osteoarthritis. The significant decrease in VAS scores observed at all follow-up points suggests that TKA can be a successful intervention for pain management in this patient population. Future research with larger, more diverse samples and longer follow-up periods can further strengthen these findings and provide a more comprehensive understanding of TKA's long-term pain-relieving effects on knee osteoarthritis.


Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Rakshith Chakravarthy is an Orthopaedic surgeon from Bengaluru.

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