Study On The Analgesic Effect Of Adductor Canal Block For Total Knee Arthroplasty

Total knee arthroplasty?TKA?is the ideal therapy that restores function of knee joint for patients with degeneration of knee joint at the end-stage.Statistically 60%of patients suffer severe pain and 30%experience moderate pain following TKA.So it is the common goal of anesthesiologist and surgeon to provide perfective perioperative analgesic for patients following TKA.Adductor canal block?ACB?can reduce the pain score and the dosage of opioids and be beneficial to early recovery for patients following TKA.However,the puncture location for ACB is controversial.In this study,we will investigate the puncture location,effective dose of ropivacaine,analgesic effect and effect for inflammatory reaction of adductor canal block for patients following TKA.Part one The puncture location for adductor canal blockObjective To discuss the accurate puncture location for adductor canal block using ultrasound.Methods Twenty patients with non-left lower extremity surgery were scanned anatomic structure of left thigh using ultrasound from the anterior superior iliac spine to the base of patella.The femoral triangle?FT?,adductor canal?AC?,beginning of adductor canal?BAC?and terminal point of adductor canal?TAC?were identified and marked.The base of patella,the greater trochanter,the anterior superior iliac spine,the midpoint of the anterior superior iliac spine and the patella?MT?and the midpoint of the greater trochanter and the patella?HT?were marked.The distances from the base of patella to MT,HT,BAC,TAC and the length of AC were measured.Results The FT,BAC and TAC were identified in all subjects using ultrasound.The distances from the base of patella to MT was 23.32±1.23,the distances from the base of patella to HT was 16.06±1.26,the distances from the base of patella to BAC was 18.63±1.31,the distances from the base of patella to TAC was 9.73±0.82 and the length of AC was 8.96±1.00.The location of BAC was distal to MT in all subjects.The location of BAC was proximal to HT in 18 subjects and distal to HT in 2 subjects?1.5 and 2.3 cm?.Conclusion In this study of 20 subjects,under ultrasound,MT was in the femoral triangle and BAC was distal to MT.The accurate puncture location for adductor canal block using ultrasound was in the level of HT.Part two Study on analgesic effect of saphenous nerve block in different approaches for total knee arthroplastyObjective To compare the analgesic effect of saphenous nerve block in different approaches for total knee arthroplasty.Methods Sixty patients undergoing TKA were randomly divided into two groups:Group ACB and Group saphenous nerve block in femoral triangle?FTSNB?.The VAS scores were assessed at 4,8,24,48 and 72 h after saphenous nerve block at rest and during activity.The muscle strength of quadriceps femoris were assessed at 4,8,24,48 and 72 h after saphenous nerve block.The incidence of use pethidine and adverse effects and patient satisfaction scores were recorded at 72 h after saphenous nerve block.Results The VAS scores at rest in Group ACB was lower than in Group FTSNB at8 and 24h?P<0.05?.The VAS scores during activity in Group ACB was lower than in Group FTSNB at 4,8,24 and 48 h?P<0.05?.The muscle strength of quadriceps femoris in Group ACB was higher than in Group FTSNB at 4,8 and 24h?P<0.05?.The incidence of use pethidine in Group ACB was lower than in Group FTSNB at 72 h after saphenous nerve block?P<0.05?,but the incidence of adverse effects and patient satisfaction scores were not different significantly in Group ACB and Group FTSNB?P>0.05?.Conclusion Both ACB and FTSNB can provide effective analgesic for patients following TKA.However,ACB is superior to FTSNB in terms of analgesic effect and motor function.Part three Study on effective volume in 50%patients of ropivacaine for adductor canal blockObjective To investigate the effective volume in 50%patients(EV₅₀)of ropivacaine for ACB.Methods Twenty-four patients undergoing TKA were carried out ACB with 0.5%ropivacaine.The EV₅₀ of ropivacaine was determined by up and down sequential trial.The initial volume of ropivacaine was set at 20 ml,and the ratio between the two successive volume was 1:1.2.Each time the volume increased or decreased in the next patient according to whether or not the sensory block was complete at 0.5 h after injected ropivacaine.The EV₅₀and 95%confidence interval of 0.5%ropivacaine for ACB were calculated.Results The EV₅₀ and 95%confidence interval of 0.5%ropivacaine for ultrasound-guided ACB was 10.79 ml?10.10,11.52?.Conclusion The EV₅₀of 0.5%ropivacaine for ultrasound-guided ACB was 10.79 ml.Part four Effect of local application dexmedetomidine on the effective concentration in 50%patients of ropivacaine for adductor canal blockObjective To investigate the effect of local application dexmedetomidine on the effective concentration in 50%patients(EC₅₀)of ropivacaine for ACB.Methods Fifty-four patients undergoing TKA were divided into two groups:control group?Group C?and dexmedetomidine group?Group D?.ACB was performed using only ropivacaine in Group C.In Group D the mixture of ropivacaine and 1?g/kg dexmedetomidine was used for ACB.The EC₅₀ of ropivacaine was determined by up and down sequential trial.The initial concentration of ropivacaine was set at 0.5%,and the ratio between the two successive concentration was 1:1.2.Each time the concentration increased or decreased in the next patient according to whether or not the sensory block was complete at 0.5 h after injected ropivacaine.The EC₅₀ and 95%confidence interval of ropivacaine for ACB were calculated.Results The EC₅₀ and 95%confidence interval of ropivacaine for ultrasound-guided ACB was 0.38%?0.36%,0.41%?in Group C and 0.29%?0.28%,0.31%?in Group D.The EC₅₀ of ropivacaine for ultrasound-guided ACB was lower in Group D than in Group C?P<0.05?.ConclusionThe EC₅₀ of ropivacaine could be decreased by local application dexmedetomidine for ultrasound-guided ACB.Part five Study on analgesic effect of adductor canal block and local infiltration analgesia for total knee arthroplastyObjective To investigate the analgesic effect of ACB and local infiltration analgesia?LIA?for total knee arthroplasty and the effect for inflammatory reaction.Methods Sixty patients undergoing TKA were randomly divided into two groups:contral group?Group C?and ACB group?Group ACB?.LIA was performed in Group C.In Group ACB,LIA and ACB were used for TKA.The VAS scores were assessed at 4,8,24,48 and 72 h after surgery at rest and during activity.The muscle strength were assessed at4,8,24,48 and 72 h after surgery.The incidence of use pethidine and adverse effects and patient satisfaction scores were recorded at 72 h after surgery.The blood samples were acquired to measure the concentration of IL-6 and IL-10 before surgery and 8,24,48 and72 h after surgery.Results The VAS scores at rest in Group ACB was lower than in Group C at 8,24,48 and 72h after surgery?P<0.05?.The VAS scores during activity in Group ACB was lower than in Group C at 4,8,24,48 and 72 h after surgery?P<0.05?.The muscle strength in Group ACB was lower than in Group C at 4h after surgery?P<0.05?,the muscle strength at 8,24,48 and 72 h after surgery were not different significantly in both group?P>0.05?.The patient satisfaction scores was higher than in Group C at 72 h after surgery?P<0.05?,the incidence of use pethidine in Group ACB was lower than in Group C at 72 h after surgery?P<0.05?,but the incidence of adverse effects were not different significantly in Group ACB and Group C?P>0.05?.The plasma concentration of IL-6and IL-10 in Group ACB was lower than in Group C at 8,24,48 and 72 h after surgery?P<0.05?.Conclusion Under the background of multimodal analgesia,LIA and ACB is superior to LIA in terms of analgesic effect,ratio of utility opioid,satisfaction of patient and the effect of anti-inflammatory.