Tourniquet cuff pressure and nerve injury in knee arthroplasty in a bloodless field

Abstract

Background and purpose Tourniquet-related nerve injuries remain a concern in orthopedic surgery. The cuff pressures used today are generally lower, and therefore a decreasing incidence of peripheral nerve injuries might also be expected. However, there have been few neurophysiological studies describing the outcome after bloodless field surgery. We describe the results of neurophysiological examinations and report the incidence of nerve injuries after total knee arthroplasty (TKA) in a bloodless field.

Patients and methods This study was part of a prospective, randomized controlled clinical trial in patients scheduled for TKA in a bloodless field. 20 consecutive patients were enrolled. Electroneurography (ENeG) and quantitative sensory testing (QST) of thermal thresholds were performed on day 3. These tests were repeated 2 months after surgery when electromyography (EMG) with a concentric-needle electrode was also performed.

Results The mean tourniquet cuff pressure was 237 (SD 33) mmHg. Electromyographic signs of denervation were found in 1 patient, who also had the highest cuff pressure in the study population (294 mmHg). The sensory nerve response amplitudes were lower in the operated leg on day 3; otherwise, the neurophysiological examinations showed no differences between the legs.

Interpretation When low tourniquet cuff pressures are used the risk of nerve injury is minor.

CO: study design, inclusion of patients, data analysis, follow-up, and writing of the manuscript. RB and SP: study design and provision of feedback on the manuscript. BRS: study design, neurophysiological examinations, and provison of feedback on the manuscript. BYN: study design, neurophysiological examinations, recording of data, data analysis, and provision of feedback on the manuscript.

We thank Lena Bergqvist, registered neurophysiology technician, who organized and performed most of the electroneurography examinations. The first author was given time for research work by the Department of Orthopedics, Södersjukhuset, Stockholm. The examinations carried out were financed by funds from the Karolinska Institute.

No competing interests declared.