Significantly earlier ambulation and reduced risk of near-falls with continuous infusion nerve blocks: a retrospective pilot study of adductor canal block compared to femoral nerve block in total knee arthroplasty

Abstract

Background Near-falls should be detected to prevent falls related to the earlier ambulation after Total knee arthroplasty (TKA). The quadriceps weakness with femoral nerve block (FNB) has led to a focus on adductor canal block (ACB). We purposed to examine the risk of falls and the earlier ambulation in each continuous infusion nerve block. Methods Continuous infusion nerve block (FNB or ACB) was performed until postoperative day (POD) 2 or 3. Pain levels and falls/near-falls with knee-buckling were monitored from POD 1 to POD 3. The score on the manual muscle test, MMT (0 to 5, 5 being normal), of the patients who could ambulate on POD 1, was investigated. Results A total of 73 TKA cases, 36 FNB and 37 ACB, met the inclusion criteria. No falls were noted. But episodes of near-falls with knee-buckling were witnessed in 14 (39%) cases in the FNB group and in 4 (11%) in the ACB group (p = 0.0068). In the ACB group, 81.1% of patients could ambulate with parallel bars on POD 1, while only 44.4% of FNB patients could do so (p = 0.0019). The quadriceps MMT values in the ACB group was 2.82, significantly higher than 1.97 in the FNB group (p = 0.0035). There were no significant differences in pain as measured with a numerical rating scale (NRS) and rescue analgesia through POD 3. Conclusion ACB was associated with significantly less knee-buckling and earlier ambulation post-TKA, with better quadriceps strength. Our study indicated the incidence of falls and near-falls with continuous infusion nerve blocks, and support the use of ACB to reduce the risk of falls after TKA. It is suggested that a certain number of the patients even with continuous ACB infusion should be considered with the effect of motor branch to prevent falls.

Application of Preoperative Adductor Canal Block Coupled with General Anaesthesia in Elderly Patients Undergoing Total Knee Arthroplasty

“…The ACB is assumed to serve the purpose of preserving quadriceps muscle strength since the block is performed distal to the motor fibre branches of the femoral nerve (with the exception of the nerve to the medial femoral muscle). Such is a point for clinicians to be aware of as well [ 19 , 20 ].…”

Safety and Efficacy of Early Rehabilitation With Assistance From a Single-Joint Hybrid Assistive Limb in Patients With Total Knee Arthroplasty: A Randomized Controlled Clinical Pilot Study

“…Quadricep weakness, which increases the risk of falling, is a known complication of femoral nerve blocks [ 20 ]. However, associations between the adductor canal block, which blocks the saphenous nerve, and significantly less knee buckling post-TKA and less quadriceps strength weakness have been reported [ 21 , 22 ]. Therefore, using an adductor canal block in this study might have allowed the use of the HAL-SJ within four hours postoperatively without exacerbating pain.…”

Femoral nerve block using lower concentration ropivacaine preserves quadriceps strength while providing similar analgesic effects after knee arthroscopy

“…Peripheral nerve block anaesthesia/analgesia is now irreplaceable after knee surgery and is not associated with complications [ 22 ]. Among them, ACB is considered a motor-sparing block and seems to have a similar effect on postoperative analgesia following total knee arthroplasty while preserving quadriceps strength [ 12 , 14 , 15 , 25 ], probably because ACB is performed distal to where the motor fibres of the femoral nerve have branched off. However, a reduction in quadriceps strength of 52% of baseline strength in patients with continuous ACB was reported by Jager et al [ 14 ].…”