Review on Nerve Blocks Utilized for Perioperative Total Knee Arthroplasty Analgesia

[Comparison of the effects of sciatic nerve block combined with continuted femoral nerve block or continuted adductor canal block on pain and motor function after total knee arthroplasty]

Objective

To compare the effect of sciatic nerve block (SNB) combined with continuted femoral nerve block (FNB) or continuted adductor canal block (ACB) on pain and motor function after total knee arthroplasty (TKA).

Methods

A total of 60 patients with TKA-treated osteoarthritis of the knee who met the selection criteria were enrolled between November 2020 and February 2021 and randomised allocated into the study group (SNB combined with continuted ACB) and the control group (SNB combined with continuted FNB), with 30 cases in each group. There was no significant difference in gender, age, body mass, height, body mass index, preoperative Hospital for Special Surgery (HSS) score, femoral tibial angle, and medial proximal tibial angle between the two groups ( P>0.05). The operation time, the initial time to the ground, the initial walking distance, and the postoperative hospital stay were recorded. At 2, 4, 6, 12, 24, and 48 hours after operation, the numerical rating scale (NRS) score was used to evaluate the rest pain around the knee joint, the quadriceps femoris muscle strength was evaluated by the freehand muscle strength method, and the knee flexion and extension angles were measured.

Results

There was no significant difference in the operation time and initial walking distance between the two groups ( P>0.05); the initial time to the ground and postoperative hospital stay of the study group were significantly shorter than those of the control group ( P<0.05). Except for the 48-hour postoperative NRS score of the study group, which was significantly lower than that of the control group ( P<0.05), there was no significant difference in the NRS scores between the two groups at the remaining time points ( P>0.05). The quadriceps femoris muscle strength from 4 to 24 hours postoperatively and the knee extension angle from 2 to 6 hours postoperatively of the study group were significantly better than those of the control group ( P<0.05); the differences in the quadriceps femoris muscle strength and knee extension and flexion angles between the two groups at the remaining time points were not significant ( P>0.05).

Conclusion

SNB combined with either continuted ACB or continuted FNB can effectively relieve pain in patients after TKA, and compared with combined continuted FNB, combined continuted ACB has less effect on quadriceps femoris muscle strength, and patients have better recovery of knee flexion and extension mobility.

Pain Control Associated With Gabapentinoid Prescription After Elective Total Knee Arthroplasty

BACKGROUND

Gabapentinoid (GABA) prescribing has substantially increased as a nonopioid analgesics for surgical conditions. We examined the effectiveness of GABA use for postoperative pain control among patients receiving total knee arthroplasty (TKA).

METHODS

This retrospective cohort study using 2016 to 2019 data from a 20% national sample of Medicare enrollees included patients aged 66 and over years who received an elective TKA, were discharged to home, received home health care, and had both admission and discharge assessments of pain (n = 35,186). Study outcomes were pain score difference between admission and discharge and less-than-daily pain interfering with activity at discharge. Opioid and GABA prescriptions after surgery and receipt of nerve block within 3 days of surgery were also assessed.

RESULTS

There were 30% of patients who had a pain score decrease of 3 to 4 levels and 55.8% had pain score decreases of 1 to 2 levels. In multivariable analyses, receiving a nerve block was significantly associated with pain score reduction. A GABA prescription increased the magnitude of pain score reduction among those receiving a nerve block. Results from inverse probability weighted analysis with propensity score showed that coprescribing of GABA and low-dose opioid was associated with significantly lower pain scores.

CONCLUSIONS

Post-TKA opioid use was not associated with pain score reduction. Receiving a nerve block was associated with a modest pain score reduction. Co-prescribing GABA with low-dose opioid or receiving a nerve block was associated with increasing magnitudes of pain reduction. Further research should identify alternatives to opioid use for managing postoperative TKA pain.

IPACK Block Efficacy for Acute Pain Management after Total Knee Replacement: A Review

PURPOSE OF REVIEW

Patients often experience a significant degree of knee pain following total knee replacement (TKR). To alleviate this pain, nerve blocks may be performed such as the adductor canal block (ACB). However, ACBs are unable to relieve pain originating from the posterior region of the knee. A new type of nerve block known as the IPACK block may be used in conjunction with ACBs as it is designed to inhibit nerve branches innervating this area. In this article, we examine the rationale behind the IPACK procedure, how it is performed, and clinical trials examining its efficacy.

RECENT FINDINGS

5 of the 7 clinical trials examined in this article showed the IPACK + ACB block to show superior efficacy in treating pain following TKR compared to other blocks. These blocks included PMDI+ACB, SPANK+ACB, PAI+ACB, ACB alone, and SCAB. 2 of the 7 clinical trials showed the IPACK + ACB to be less effective in managing patients pain following TKR compared to other blocks which included the CACB and 4 in 1 block. In most instances, the IPACK + ACB showed superior efficacy in managing patients' pain following TKR when compared to other types of nerve blocks. This was determined by measuring usage of opioids, reported postoperative pain, and length of hospital stays following TKR. Thus, we suppose the IPACK block may be used in conjunction with the ACB to effectively reduce patient's pain following TKR.

Predictive Ability of Perfusion Index for Determining the Success of Adductor Canal Nerve Block for Postoperative Analgesia in Patients Undergoing Unilateral Total Knee Arthroplasty

BACKGROUND

The perfusion index (PI) is an objective method used to determine a successful nerve block. This study aimed to investigate the prognostic ability of the PI for a successful adductor canal nerve block (ACB) and suggest the optimal PI cut-off value for predicting a block.

METHODS

This study was a prospective observational study and enrolled a total of 39 patients. The patients were dichotomized into successful and inappropriate ACB groups according to the results of the sensation tests. The PI value, Pleth variability index (PVi) value, and heart rate were recorded one minute before the block, at the time of the block, and one to 30 min after the block at one-minute intervals. Delta (dPI), which was defined as the difference in PI value from the baseline (the value one minute before the block), was the primary outcome. The area under the receiver operating characteristic curve (AUROC) was calculated to determine the dPI prognostic accuracy and optimal cut-off value.

RESULTS

Successful ACB was achieved in 33 patients, while ACB was inappropriate in six patients. The dPI showed significant differences between the two groups under the time interval measured (p = 0.001). The dPI at 5 and 20 min showed good prognostic ability for a successful block, with optimal cut-off values of 0.33 (AUROC: 0.725, 95% CI 0.499-0.951) and 0.64 (AUROC: 0.813, 95% CI 0.599-1.000), respectively.

CONCLUSIONS

The dPI is an effective predictor of successful ACB. The suggested dPI cut-off values at 5 and 20 min were below 0.33 and 0.64, respectively.