Regional anaesthesia advocated for certain patients undergoing knee replacement

For patients undergoing primary unilateral total knee arthroplasty (TKA), regional anaesthesia results in a shorter stay in the hospital compared with general anaesthesia, especially among elderly patients and those with normal weight or obesity, as shown in a study from Singapore.

In a cohort of 2,309 patients, the length of hospital stay was shorter by 0.78 days among those who received regional anaesthesia than those who were given general anaesthesia. On further analyses, the relationship between anaesthetic type and hospital stay was modified by age and body mass index (BMI), such that the beneficial effect of regional anaesthesia was stronger among elderly patients (age ≥65 years) and those whose body mass index (BMI) was ≤25 kg/m² or ≥30 kg/m². [J Orthop Surg Res 2021;16:671]

Therefore, according to the researchers, priority for regional anaesthesia is given to the said patient subgroups when TKA is performed.

“Anaesthesia is an important step to ensure the success of the surgery… General anaesthesia is associated with higher rates of postoperative nausea, vomiting, and delirium. On the other hand, regional anaesthesia may be complicated by block failure and destructive complications including epidural abscess, spinal hematoma, and nerve injury,” the investigators said.

The mentioned complications prolong the length of hospital stay, which is considered a key measure of healthcare efficiency and resource utilization. The investigators pointed out that identifying factors to reduce the stay is critical to improving patient care and hospital performance, given that a shorter stay leads to a lower risk of infection and medication side effects as well as increased hospital profit owing to efficient bed management. [J Bone Miner Metab 2019;37:307-318; Cochrane Database Syst Rev 2010;3:CD006632]

In the current study, 791 patients (34.3 percent) received general anaesthesia, whereas 1,518 patients were administered regional anaesthesia. Several risk factors for prolonged length of hospital stay emerged on multivariate regression analyses. These included age ≥65 years (β, 0.48, 95 percent confidence interval [CI], 0.09–0.87; p=0.015), diabetes mellitus (β, 0.8, 95 percent CI, 0.33–1.27; p=0.001), congestive cardiac failure (β, 4.1, 95 percent CI, 2.02–6.17; p<0.001), perioperative blood transfusion (β, 5.71, 95 percent CI, 4.86–6.56; p<0.001), creatinine >2 mg/dL (β, 4.54, 95 percent CI, 2.46–6.62; p< 0.001), the American Society of Anesthesiologists  status III (β, 1.72, 95 percent CI, 0.72–2.71; p=0.001), and general anaesthesia (β, 0.78, 95 percent CI, 0.41–1.66; p<0.001).

On the other hand, receipt of regional anaesthesia reduced the length of stay among patients at advanced age (β, –1.12, 95 percent CI, –1.66 to –0.58; p<0.001), patients with BMI ≤25 kg/m² (β, –1.92, 95 percent CI, –2.73 to –1.11; p<0.001) or ≥30 kg/m² (β, –0.58, 95 percent CI, –1.1 to –0.06; p=0.029).

“This work utilized an extended model approach to adjust the potential confounders and performed subgroup and interaction analyses to ensure a stable relationship between the anaesthetic method and length of stay,” according to the researchers.

Nevertheless, they acknowledged that the results could not be generalized to people of other ethnicities in different countries, as the study population mostly included Chinese patients.

“Importantly, this study did not specify the regional anaesthetic method that had been used. As such, further exploratory studies are essential to analyse a more suitable regional anaesthesia for TKA from the perspective of shortening length of stay,” they added.