Blood flow restriction training as a prehabilitation concept in total knee arthroplasty: A narrative review about current preoperative interventions and the potential impact of BFR

Osteoarthritis of the knee is one of the most commonly diagnosed joint ailments and responsible for increased rates of total knee arthroplasty surgeries worldwide. Whereas the surgical approach is able to diminish the perceived knee pain of concerned patients', the postoperative recovery is often accompanied by persistent skeletal muscle dysfunctions and atrophy, which is responsible for functional deficits for up to several years. Recent findings indicate that surgery induced adverse effects on skeletal muscles are largely associated with the use of pneumatic tourniquets, wherefore several studies try to reduce tourniquet use in orthopedic surgery. However, due to comparable incidence of muscle impairment and increased surgical challenge, the most frequently applied surgical technique in TKA is still associated with the use of tourniquets. When attenuating TKA induced adverse effects, the preoperative preparation of patients by specific exercises (called prehabilitation) was able to enhance preoperative overall fitness through associated accelerated recovery. Based on patients' limited functional activity, prehabilitation techniques have to be particularly designed to allow regular adherence. The present paper is based on a narrative review of current literature, and provides a novel hypothesis by which blood flow restriction exercises (BFR) are able to improve patients' compliance to prehabilitation. BFR training is characterized by the application of low-resistance exercise with similar intensities as daily living tasks in association with a suppression of venous blood flow in an extremity, achieving significant morphological and neuromuscular adaptations in skeletal muscles. In addition, preoperative enhancements in muscle health with corresponding benefits in overall fitness, BFR induced molecular alterations could also be able to interfere with TKA induced pathological signaling. Therefore, based on the known major impact of BFR on skeletal muscle physiology, the present paper aims to illustrate the potential beneficial impact of BFR training as a pre-habilitation concept to promote patients regular adherence to preoperative exercises and thus achieve an accelerated recovery and increases in patients' satisfaction.