Tourniquet cuff pressure and nerve injury in knee arthroplasty
in a bloodless field - A neurophysiological study
Charlotta Olivecrona1. Richard Blomfeldt1. Sari Ponzer1. Benjamin Ribalta Stanford2. and Bengt Y Nilsson2
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.