Background and aims Equinus foot due to damage of the common peroneal nerve is a dreaded complication after total knee arthroplasty (TKA) and high tibial osteotomy (HTO) but can also occur after sciatic nerve block (SNB). We have previously reported the risk factors of equinus foot after TKA with SNB and introduced selective tibial nerve block (STNB) instead of SNB. The aim of this retrospective cohort study was to compare STNB and SNB with respect to the postoperative equinus foot incidence in HTO.

Methods After institutional review board approval and informed consent, we reviewed the medical charts of 198 consecutive ASA-PS 1–2 patients who underwent HTO under general anesthesia with SNB using 0.125% levobupivacaine 10–40 ml or STNB using the same less than 10 ml. The primary outcome was the incidence of postoperative equinus foot incidence using Fischer’s exact test.

A p<0.05 was considered statistically significant.

Multivariable logistic regression analysis was used to determine significant equinus foot predictors.

Results There were 171 cases of SNB and 27 cases of STNB during the study period. While equinus occurred in 17 cases after SNB and none after STNB, this difference did not reach statistical significance (p=0.136). Logistic regression analysis revealed that the amount of local anesthetics was significantly associated with the occurrence of postoperative equinus foot (odds ratio 1.18 [95% confidence interval: 1.02–1.38]).

Conclusions No postoperative equinus foot was observed after STNB. This may be because of the use of smaller amount of local anesthetic.