Popliteal plexus block compared with tibial nerve block on rehabilitation goals following total knee arthroplasty: a randomized non-inferiority trial

doi:10.21203/rs.3.rs-4847589/v1

This trial examined the effectiveness of the popliteal plexus block (PPB) and tibial nerve block (TNB) for early rehabilitation after total knee arthroplasty (TKA). We allocated 136 participants to receive PPB or TNB with 0.25% levobupivacaine 10 mL in a randomized, double-masked manner. The primary outcome was achieving rehabilitation goals with a non-inferiority 9-hour margin, including adequate pain relief, knee flexion angles over 90 degrees, and enabling ambulatory rehabilitation. The time to reach rehabilitation goals showed non-inferiority with 49.7 ± 10.5 hours for TNB and 47.4 ± 9.7 hours for PPB, whose mean difference (PPB - TNB) was − 2.3 hours (95% CI -5.8 to 1.2 hours; P < 0.001). PPB showed higher dorsal and plantar percentage of maximum voluntary isometric contraction (dorsal, PPB 87.7% ± 11.4% vs. TNB 74.0% ± 16.5%: P < 0.001; plantar, PPB 90.9% ± 10.3% vs. TNB 72.1% ± 16.0%; P < 0.001) at six hours after nerve block. No significant differences between the two groups emerged in pain scores, knee range of motion, additional analgesic requirements, success in the straight leg raise, and adverse events. PPB exhibited non-inferiority to TNB in achieving postoperative rehabilitation goals and had superiority in preserving foot motor strength after TKA. (200)

Health sciences/Medical research

Health sciences/Medical research/Outcomes research

Health sciences/Diseases

Health sciences/Health care

Health sciences/Health care/Therapeutics

Health sciences/Health care/Therapeutics/Pain management

Health sciences/Health care/Therapeutics/Rehabilitation

Total knee arthroplasty

Ultrasound-guided

Peripheral nerve block

Lower extremity

Rehabilitation

Acute postoperative pain

Total knee arthroplasty (TKA) is a surgical procedure that effectively alleviates pain and enhances mobility for individuals suffering from knee joint disorders. It is widely known that a combination of regional anesthesia, including peripheral nerve blocks (PNB), and multimodal analgesic techniques is effective in obtaining postoperative analgesia for TKA. [1] Periarticular injection (PAI) and selective tibial nerve block have been reported to be useful in obtaining postoperative analgesia in the posterior knee joint while preserving ankle joint motion. [2] In addition, the interspace between the popliteal artery and the posterior capsule of the knee block (IPACK) has also been shown to provide good quality analgesia when combined with adductor canal block (ACB) or femoral triangular block (FTB) while preserving lower leg motor function. [3]

Although previous studies have shown that TNB was less likely to cause the common peroneal nerve block than SNB [4], thus preserving postoperative dorsal foot motion, it is worth noting that TNB may affect ankle mobility, depending on the extent of local anesthetic spread. [5] Additionally, a case report observed IPACK causing spread to the terminal branch of the sciatic nerve, leading to a motor deficiency of dorsal foot motion known as "foot drop" [6].

Popliteal plexus block (PPB) is a procedure where local anesthetics are injected into the adductor canal, positioned about 1–2 cm above the adductor hiatus. The injected solutions then disperse distally to the adductor hiatus and towards the popliteal fossa. To mitigate the risk of SNB, limiting the volume of local anesthetic to 10-15 mL is recommended, allowing for the blockage of the genicular nerve, posterior obturator, and tibial nerves [7-9]. Recent research showed that PPB with FTB resulted in a significant reduction in postoperative opioid consumption after TKA compared with FTB or ACB alone. [10]

This study aims to investigate the impact of PPB on the postoperative pain management and rehabilitation progress following TKA combined with a single-shot ACB. We hypothesize that PPB will demonstrate non-inferiority to TNB in achieving rehabilitation objectives during the early postoperative period. Our secondary outcomes of interest include postoperative pain scores, ankle mobility gauged through muscle strength assessment, knee range of motion (ROM), additional analgesics, and potential adverse events.

This study included 136 patients (Figure 2), of whom 132 completed the protocols; four were excluded due to protocol violations. Patient demographics were not significantly different (Table 1).

Analysis of the primary outcome showed a difference in the mean time to reach rehabilitation goals between the TNB (49.7 ± 10.5 hours) and PPB (47.4 ± 9.7 hours) groups of -2.3 hours (95% CI -5.8 to 1.2 hours; P < 0.001) (Table 2). The upper CI of the difference was lower than the non-inferiority margin (Figure 3).

No significant differences in NRS scores at rest or during knee flexion were observed between the groups at any point (Figure 4). No statistical differences were found in knee ROM, ability to perform the SLR test at any time point, additional analgesic requirements, and incidence of postoperative adverse events, including postoperative nausea and vomiting, falls, and pruritus (Table 2).

The dorsal and plantar %MVIC 6 hours after PNB were significantly higher in the PPB group (dorsal, PPB 87.7% ± 11.4% vs. TNB 74.0% ± 16.5%; difference, 13.6% [8.8%-18.5%]; P < 0.001; plantar, PPB 90.9% ± 10.3% vs. TNB 72.1% ± 16.0%; difference, 18.9% [14.2%-23.5%]; P < 0.001, Table 2). However, both %MVIC 24 hours after PNB were insignificant between the two groups.

This trial demonstrated that PPB showed non-inferiority to TNB in achieving rehabilitation goals, including knee flexion, ambulation, and pain control with oral analgesics after TKA. Regarding secondary outcomes, PPB maintained statistically higher levels of dorsi flexion and plantar flexion muscle strength six hours after surgery. When examining postoperative NRS pain scores, frequency of analgesic use, knee ROM, and adverse effects, the results emphasized PPB as a viable alternative to TNB for post-TKA pain management.

The actual value and 95% CI, assuming non-inferiority in postoperative rehabilitation goals, indicates that at least PPB did not increase the time to meet the discharge criteria beyond the standard 9 hours compared to TNB, and 95% CI for the difference between the two groups ranges from − 5.8 hours to 1.2 hours, showed no clinically significant impact on outcome. The ability of PPB to achieve rehabilitation outcomes without lagging behind TNB has several advantages, including prompt postoperative gait training, appropriate analgesia with oral medications, and knee flexion rehabilitation. These factors help to reduce postoperative disability, resulting in early recovery, discharge, and lower medical costs [11]. As demonstrated in this study, PPB excels in maintaining dorsi flexion and plantar flexion.

Additionally, PPB reduces the risk of the common peroneal nerve block compared to TNB, potentially impacting the immediate postoperative demonstration of the absence of surgical common peroneal nerve injury. PPB can be performed in the same leg position as ACB, making it more accessible than TNB, which requires a change in leg position. Furthermore, the comparable results regarding the ability to perform SLR suggest that the combination of proximal ACB with TNB or PPB did not affect quadriceps motor weakness in the early period after TKA. The absence of differences in postoperative adverse effects, including nausea, vomiting, falls, and pruritus, suggests that our study setting did not interfere with rehabilitation progress immediately after TKA.

Anatomical evidence from a cadaveric study has clarified the neural branches innervating the posterior knee capsule, including the posterior division of the obturator and tibial nerves, articular branches of the common peroneal nerve, and the sciatic nerve, which form the intricate popliteal plexus [12]. This anatomical understanding supports the augmentation of femoral triangle block or ACB combined with obturator or sciatic nerve block to improve postoperative pain control after TKA [13, 14]. In addition, TNB has emerged as a viable pain management technique that provides adequate blockade of the posterior division of the tibial nerve while avoiding ankle motor impairment [4]; however, the recent trial showed TNB had no superior analgesic efficacy compared to the local infiltration analgesia in the posterior knee capsule. [15]

We consider that the advent of the IPACK technique highlights its efficacy in targeting the terminal branches of the sciatic and posterior obturator nerves, which innervate the posterior knee capsule. A cadaveric study showed that both the proximal and distal IPACK injection methods resulted in comparable dye distribution within the popliteal region and extensive staining of the articular branches supplying the posterior capsule [16]. In contrast, PPB extends the dye from the adductor canal into the posterior knee, encompassing the popliteal area through the adductor hiatus [8, 17]. This spread depends on the volume of local anesthetic administered [9]. PPB delivers local anesthetic to a more superficial area around the adductor canal and femoral artery than IPACK. Our study suggests that this indirect distribution effectively provides adequate analgesia for post-TKA, as evidenced by postoperative NRS scores.

A previous study compared the administration of 0.25% levobupivacaine (20ml) in TNB, proximal IPACK, and distal IPACK. The results demonstrated that the two IPACK procedures were significantly less likely to induce motor weakness than TNB [18]. The present study showed that administering a reduced quantity of levobupivacaine in either PPB or TNB was an efficacious method for providing postoperative pain relief while simultaneously preserving the muscle strength of plantar and dorsi flexion at the six-hour postoperative mark. Notably, our study employed a lower dosage than that utilized in previously published PAI or IPACK protocols [19, 20]. These results provide a rationale for selecting PPB in institutions prioritizing early gait training within 24 hours of the surgery. However, we should notice that this difference became practically insignificant 24 hours after surgery. A previous clinical finding indicated that the injection of local anesthetic and contrast solutions into the adductor canal distributes to the sciatic nerve territory via the adductor hiatus without resulting in foot motor weakness. [21] Another cadaveric study demonstrated a significant proximal spread of local anesthetic after TNB, which may result in unwanted motor blocks of the peroneal nerve. [5] The results of our trial confirm those of previous studies indicating that TNB may induce motor weakness in dorsal foot movement due to the common peroneal nerve block. While muscle sparing is advantageous in fast-track rehabilitation programs, especially when early gait training is initiated after surgery, avoiding excessive local anesthetic administration is critical to prevent inadvertent spread to the sciatic nerve. Therefore, selecting a nerve block technique such as PPB that does not significantly reduce foot motor function is beneficial.

Effective pain management is of paramount importance for the active engagement of patients in the early postoperative rehabilitation process [22]. Some institutions have implemented an accelerated gait rehabilitation program for patients discharged on postoperative day (POD) 0 or POD 1, intending to reduce hospital stay and healthcare costs [23, 24]. However, the surgical team hesitated to perform gait training on POD 0 due to the participants' advanced age and declining physical abilities. Moreover, the surgical team hypothesized that initiating gait training on POD 0 would not markedly reduce the duration of hospitalization compared to commencing on the morning of POD 1, based on the findings of a prior study [22]. Variations in postoperative management and rehabilitation strategies have resulted in discrepancies in length of stay and rehabilitation objectives across institutions [25, 26].

It is important to acknowledge the limitations of this study, particularly concerning the relatively large non-inferiority margin for the primary outcome. The margin may not have fully reflected the reality in other institutions prioritizing early rehabilitation. The larger margin for rehabilitation goals was accepted because our institution did not have a predisposition for postoperative management of gait training on the same day after surgery. Additionally, early discharge within one day after surgery did not contribute to our hospital revenue in terms of national insurance reimbursement. Furthermore, the start time of postoperative rehabilitation interventions was set at a later point in the day, with a larger margin, due to the assumption that the difference of up to 9 hours between early morning and afternoon interventions would not contribute to hospital revenue. Nevertheless, evidence from other countries indicates that a narrower margin may be more appropriate. In settings with intensive rehabilitation, increasing the sample size may enhance the statistical power of the study. Earlier rehabilitation and discharge could diminish the healthcare resource consumption associated with pain management therapy and potentially augment hospital revenue while reducing national health insurance costs. [27]

Our view is that the achievement of the primary endpoint is an indicator of the success of the surgery. It should be noted, however, that each participant's knee mobile ability and walking ability may vary. In addition, the mere administration of regional anesthesia to relieve postoperative pain does not necessarily guarantee a positive surgical outcome. Therefore, the primary outcome was limited to measuring participants' ability following TKA for early discharge, including pain, ambulation, and knee flexibility. Furthermore, at the trial outset, we did not regard IPACK as a procedure that could be meaningfully compared with PPB or TNB. Future studies should evaluate the postoperative analgesic and motor-sparing effects of IPACK versus PPB plus proximal ACB. In our study, we limited the volume of a local anesthetic to 10ml for PPB or TNB based on a cadaver study that indicated the potential for spread from the proximal adductor canal to the posterior knee, which could affect outcomes. [17, 28] Because the optimal dose of local anesthetic required to achieve analgesia of the posterior knee and knee capsule varies with patient background and surgical invasiveness, differences in motor function may be observed with increasing doses of local anesthetic.

The results confirmed that PPB had non-inferiority to TNB in accelerating the achievement of postoperative rehabilitation goals. In addition, PPB demonstrated superiority in preserving ankle strength in the early postoperative period.

Patients, blinding, and allocation

This study adhered to the principles of the Declaration of Helsinki, and data presentation followed the guidelines of the CONSORT statement. The Institutional Review Board of Daiyukai General Hospital approved the trial protocol (No. 2019-024, March 4, 2020), and all participating patients provided written informed consent. Before patient recruitment, the study was registered in the University Hospital Medical Information Network (UMIN000040054, registered on 04/April/ 2020, URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045668). Recruitment for the study took place between April 6, 2020, and June 23, 2021. Inclusion criteria included patients over 20 years of age, American Society of Anesthesiologists (ASA) I-III classification, undergoing unilateral TKA for knee osteoarthritis. Exclusion criteria included unplanned implants or surgical procedures, concurrent bilateral TKA, revision TKA, allergy to study medications, chronic opioid use, neuromuscular deficits, infection, and contraindications to PNB.

Before surgery, participants were randomly assigned to receive either PPB or TNB using a computer-generated random number sequence with a block size of 4 and an allocation ratio of 1:1. Information regarding treatment group allocation was concealed in a sealed envelope. All surgeons, nurses, and physiotherapists were blinded to the allocation.

Regional Anesthesia Techniques

An experienced anesthesiologist performed preoperative nerve blocks in an operating room. An electrocardiogram, pulse oximetry, and blood pressure monitoring were also performed. Peripheral intravenous (IV) access was established, and intravenous midazolam (0.03–0.04 mg/kg) was administered before block procedures for blinding. PNB procedures were performed using a high-frequency linear ultrasound transducer (Logic E Premium, GE Healthcare, Chicago, IL) and a 10-cm, 21-gauge PNB needle (Echoplex plus; Vygon, Paris, France).

The ACB procedure targeted the proximal end of the adductor canal where the medial edges of the sartorius and adductor longus muscles intersect. [28] The needle was inserted perpendicular to the nerve at this level using an in-plane approach from a lateral-to-medial direction. The needle tip was positioned at the nerve structures, including the bifurcated saphenous nerve and the vastus medialis branch. We then administered 10 mL of levobupivacaine 0.25% around the nerve.

During the TNB procedure, the subject was placed supine with the hip and knee joints flexed (Figure_1_A1). The ultrasound probe was positioned in the popliteal fossa, perpendicular to the femur, and moved slightly cephalad to locate the popliteal artery and nerve structures. The bifurcation of the sciatic nerve into the common peroneal and tibial nerves was visualized. The needle was then inserted from the lateral thigh using the in-plane technique. The needle tip was advanced into the medial aspect of the tibial nerve and approached tangentially [4] (Figure_1_A2). We then administered 10 mL of levobupivacaine 0.25% on the medial side of the tibial nerve.

For the PPB procedure, the subject remained supine with the knee slightly flexed (Figure_1_B1). The ultrasound probe was positioned at the same level as the ACB and moved downward along the femoral artery until the artery separated from the sartorius muscle at the distal end of the adductor canal, resulting in the adductor hiatus [7]. We identified the target site as the space between the vastus medialis and adductor magnus muscles, with slight posteromedial encroachment of the sartorius muscle. The needle was inserted through the vastus medialis muscle and positioned to approach the artery tangentially in the medial artery region (Figure_1_B2). We then administered 10 mL of levobupivacaine 0.25% to allow for distribution between the artery and the adductor magnus muscle.

To maintain blinding, all subjects in each group who were sedated with midazolam were positioned in the lower extremity for TNB or PPB, performed the disinfection maneuver, and then received local anesthesia with lidocaine at the intended puncture site and held in this position for 1 minute. However, the actual block needle insertion was not performed.

Perioperative Management

All participants underwent general anesthesia with a supraglottic airway. Anesthesia was induced and maintained with air/oxygen, propofol, fentanyl, and intravenous dexamethasone (3.3 mg) as an antiemetic. The same surgical team performed TKA using a mini-mid parapatellar approach with a 12–15 cm midline skin incision and the same prosthetic implant (Fine CR, Teijin-Nakashima Medical, Okayama, Japan). After patella replacement, fixation was secured with bone cement, and a drainage tube was inserted. A tourniquet was applied with an inflation pressure of 300 mmHg. Before skin closure, surgeons only injected 10 mL of ropivacaine 0.75% (75 mg) into the surgical incision line.

After surgery, all participants received 1000 mg of paracetamol by intravenous injection one hour after surgery. Subsequently, they received paracetamol 500 mg every eight hours and celecoxib 200 mg every 12 hours. If they had a patient-reported numeric rating scale (NRS) of ≥ 5 at rest, they received tramadol 25 mg. For breakthrough pain, diclofenac 50 mg was administered by suppository or pentazocine 15 mg by intramuscular injection. The drainage tube was removed on the morning of the first postoperative day.

Study results and analysis

The primary endpoint was the time to rehabilitation goal, defined as achieving an NRS ≤ 4 at rest with scheduled analgesics, walking 30 meters with a walker, and demonstrating the voluntary performance of 90° knee flexion [11, 29]. Secondary endpoints included the following: 1) NRS at rest and during knee flexion rehabilitation at 1, 6, 10, and 24 hours postoperatively, 2) active knee range of motion (ROM) on postoperative days 1–3, 3) additional analgesic requirements for 72 hours postoperatively, 4) straight leg raise (SLR) success at 1, 6, 24, and 72 hours postoperatively, defined as the ability to raise the operative limb 10 cm above the waist for at least 10 seconds in the supine position, 5) frequency of postoperative adverse events, including postoperative nausea and vomiting, falls, pruritus, and 6) assessment of maximum voluntary isometric contraction (MVIC) of foot movement.

Nurses recorded NRS scores and adverse events every two hours from 6:00 am to 10:00 pm. Physical therapists assessed patients at least twice daily (morning and afternoon), SLR test feasibility, knee ROM, and gait training, specifically the patient's ability to walk over 30 meters.

Ankle plantar and dorsi flexion strengths were measured using a handheld dynamometer (µ-TAS F1; Anima, Tokyo, Japan) as the MVIC [29]. During the measurement, the participants lay supine with the leg immobilized, and the evaluator applied the dynamometer to the plantar or dorsal foot. The evaluator instructed the participants to exert maximum effort for a 5-second contraction followed by relaxation, with the procedure repeated twice. The average of these measurements was recorded the day before surgery and 6 and 24 hours after surgery following nerve blocks. These values were expressed as a percentage of preoperative MVIC (%MVIC) [30].

Statistics and sample size calculation

To assess the non-inferiority of PPB compared to TNB, we conducted an unpublished pilot study with ten participants in each group. The mean time to achieve rehabilitation goals was 64.1 ± 14.6 hours for TNB and 60.2 ± 15.5 hours for PPB in the ten participants. Previous studies in TKA comparing continuous FNB with placebo showed a median difference of 15 hours in the time to meet discharge criteria, including pain relief, additional opioids, and ambulation [11]. Considering the acceptable non-inferiority margin that should be established relative to placebo [31], we expected the subjective difference to be approximately 50% of the previously mentioned results from a placebo-controlled trial. The standard deviation (SD) was adopted from our preliminary results; thus, each group should consist of 63 patients, with a power of 0.9, a one-sided α of 0.025, a non-inferiority margin of 9 hours, and an SD of 15.5 hours. We enrolled 136 patients, accounting for potential dropouts.

A one-tailed t-test with a significance level of 2.5% was used to test the non-inferiority hypothesis. Categorical data were presented as percentages (%) and analyzed using the chi-squared test with a calculation of the 95% confidence interval (CI) for the odds ratio. Non-normally distributed continuous and nonparametric data were expressed as median and range, and we used the Mann-Whitney U test, including a 95% CI for the median difference when possible. For normally distributed data, we reported the mean and standard deviation, along with a 95% CI, and analyzed them using Student's t-test. A two-tailed P value of less than 0.05 was considered statistically significant, except for the non-inferiority hypothesis. All statistical analyses were performed with R version 4.1.6 (The R Foundation, Vienna, Austria). (The R Foundation, Vienna, Austria).

TKA, total knee arthroplasty; PAI, periarticular injection; PNB, peripheral nerve block; FNB, femoral nerve block; FTB, femoral triangle block; ACB, adductor canal block; SNB, sciatic nerve block; TNB, tibial nerve block; ONB, obturator nerve block; IPACK, the interspace between the popliteal artery and posterior capsule of the knee block; PPB, popliteal plexus block; ROM, range of motion; CONSORT, Consolidated Standards of Reporting Trials; UMIN, University Hospital Medical Information Network; ASA, American Society of Anesthesiologists; NRS, Numeric Rating Scale for pain; SLR, straight leg raise; MVIC, maximum voluntary isometric contraction; %MVIC, percentage of preoperative MVIC; SD, standard deviation; CI, confidence interval. POD, postoperative day

Competing interest:

The authors declare no conflicts of interest.

Funding:

The authors have no sources of funding to declare for this manuscript from any funding agency in public, commercial, or not-for-profit sectors.

Ethics approval:

The Institutional Review Board of Daiyukai General Hospital approved the trial protocol (No. 2019-024, March 4, 2020), and all participating patients provided written informed consent. The study was registered in the National Registry (Study ID: UMIN40054: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045668, April 4, 2020) before patient recruitment. Participants gave informed consent to participate in the study before taking part.

Presentation:

The abstract of this trial was presented at the 39th Annual Congress of The European Society of Regional Anaesthesia and Pain Therapy in Thessaloniki, Greece, on June 23, 2022.

Author Contribution

All authors designed the study protocol. N.S., T.A., T.S., C.T., and Y.U. recruited patients and conducted this study. N.S. and T.A. analyzed the data, and C.T., T.S., and Y.U. interpreted the study data. M.T. supervised the entire study process. N.S. prepared the first draft of the manuscript, and then all authors revised it and approved the final version to be published.

Acknowledgement

Dr. Tomohiro Michino (Department of Anesthesiology, Daiyukai General Hospital, Ichinomiya, Japan) for his advice and generous contribution to the data analysis and manuscript preparation. Enago, a member of Crimson Interactive Pvt. Ltd. (http://www.enago.com/), contributed to the proofreading and editing of this manuscript.

Data Availability

The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request. In addition, sequence data that support the findings of this study have been deposited in the University Hospital Medical Information Network Clinical Trial Registry (UMIN-CTR) with the primary accession code UMIN000040054. (need UMIN ID)UMIN CTR: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045668

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Table 1 Participant characteristics and perioperative parameters

	PPB	TNB	SMD
Sample size, n	67	65
Patient characteristics
Gender, n (%)
Male	20 (29.9)	20 (30.8)	0.020
Female	47 (60.1)	45(69.2)
ASA classification, n (%)
I	8 (11.9)	4 (6.2)	0.212
II	56 (83.6)	57 (87.6)
III	3 (4.5)	4 (6.2)
Left and Right, n (%)
Left	43 (64.1)	32 (49.2)	0.305
Right	24 (35.9)	33 (50.8)
Mean age (SD) in years	76 (8)	75 (7)	0.056
Mean height (SD) in cm	154 (6)	154 (10)	0.015
Mean weight (SD) in kg	60 (10)	60 (11)	0.090
Mean BMI (SD) in kg/m²	25.0 (3.3)	25.4 (3.5)	0.122
Preoperative knee flexion (SD), degree	126 (13)	123 (15)	0.222
Preoperative knee extension (SD), degree	7 (7)	8 (7)	0.106
Surgical values
Mean duration of surgery (SD) in minutes	114 (17)	115 (16)	0.078
Mean duration of operation room occupied (SD) in minutes	165 (19)	167 (19)	0.105
Mean duration of tourniquet ischemia (SD) in minutes	105 (13)	107 (11)	0.202
Mean bleeding (SD) in mL	129 (75)	114 (56)	0.227
Mean water balance (SD) in mL	722 (267)	716 (241)	0.022

Abbreviations: SMD, standardized mean differences; SD, standard deviation; ASA: American Society of Anesthesiologists; TNB, the tibial nerve block; PPB, the popliteal plexus block

Table 2 Postsurgery outcomes for participants that underwent total knee arthroplasty

Outcomes	PPB	TNB	Difference /Odds ratio	95% CI	p.value^d,e
Sample size, n	67	65
Mean hours (SD) in achieving rehabilitation goals	47.4 (9.7)	49.7 (10.5)	−2.3^a	−5.8−1.2	< .001
Dorsiflexion %MVIC, % (SD)
Postoperative 6-hour	87.7 (11.4)	74.0 (16.5)	13.6^a	8.8−18.5	< .001
Postoperative 24-hour	92.1 (11.8)	89.6 (12.3)	2.5^a	−1.6−6.7	0.230
Plantarflexion %MVIC, % (SD)
Postoperative 6-hour, %	90.9 (10.3)	72.1 (16.0)	18.9^a	14.2−23.5	< .001
Postoperative 24-hour, %	92.7 (16.5)	93.4 (11.8)	−0.7^a	−5.6−4.3	0.795
PONV, n (%)
Yes	2 (3.0)	1 (1.5)	0.51^c	0.008−10.0	1.000
No	65 (97.0)	64 (98.5)
Falling, n (%)
No	67 (100)	65 (100)	null		null
Pruritus, n (%)
YES	2 (3.0)	0 (0)	0^c	0.000−5.48	0.496
No	65 (97.0)	65 (100)
Ability of SLR
Postsurgical, n (%)
Yes	58 (86.6)	58 (89.2)	1.29^c	0.39−4.3	0.791
No	9 (13.4)	7 (10.8)
Post 6 hours, n (%)
Yes	61 (91.0)	60 (92.3)	1.18^c	0.28−5.2	1.000
No	6 (9.0)	5 (7.7)
Post 24 hours, n (%)
Yes	62 (95.4)	58 (89.2)	1.66^c	0.31−11.2	0.718
No	5 (4.6)	7 (10.8)
Post 72 hours, n (%)
Yes	67 (100)	65 (100)	null		null
Additional analgesic requirements for postoperative 72 hours, n (%)
0 time	34 (50.7)	27 (41.5)			0.535
1 time	22 (32.8)	24 (36.9)
2 times or more	11 (16.5)	14 (21.6)
Postoperative active knee flexion, degree (SD)
POD 1	87 (15)	86 (15)	0.9^a	−4.2−6.1	0.199
POD 2	94 (10)	95 (12)	−0.4^a	−4.2−3.4	0.841
POD 3	102 (11)	104 (11)	−2.0^a	−5.8−1.9	0.311
Postoperative active knee extension, degree (SD)
POD 1	−15 (5)	−16 (4)	0.1^a	−1.5−1.6	0.946
POD 2	−8 (3)	−9 (4)	−0.4^a	−1.7−1.0	0.580
POD 3	−6 (3)	−6 (3)	−0.2^a	−1.3−0.9	0.723

Abbreviations: SD, standard deviation; IQR, interquaritile range, POD: postoperative day; TNB, tibial nerve block; PPB, popliteal plexus block; NRS, Numerical Rating Scale; SLR, straight leg raise; %MVIC, the percentage of maximum voluntary isometric contraction;
a: Mean difference (95% CI) between TNB and PPB

b: Median difference (95% CI) between TNB and PPB

c: Odds ratio (PPB/TNB) and (95% CI)

d: p-value compares PPB versus TNB

e: t-test used to compare means, Mann-Whitney U test to compare medians, and chi-squared test used to compare proportions

No competing interests reported.

Popliteal plexus block compared with tibial nerve block on rehabilitation goals following total knee arthroplasty: a randomized non-inferiority trial

Status:

Journal Publication

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Abstract

Figures

Introduction

RESULTS

Discussion

Conclusions

METHODS