Evaluation of the Analgesic Effect of Blood Flow Restriction Training in Patients With Anterior Knee Pain

Anterior knee pain is one of the prevailing musculo-skeletal pathologies amend adults. In general, anterior knee pain has an extensive differential diagnosis as it is not specific in any way. In addition to resistance exercise possible hypoalgesic effect to decrease pain perception, blood flow restriction (BFR) training may furnish a surrogate therapeutic protocol to treat anterior knee pain when added to low intensity quadriceps strengthening. The aim of the current study was to evaluate the effect of low load resistance training with BFR or sham-BFR in pain perception by measuring Pressure Pain Thresholds (PPTs) in individuals with AKP. Twenty adult male patients with AKP complaints aged ˃ 18 years were recruited and distributed randomly into 2 groups (BFR and Sham interventions). The percentage of occlusion was set between 70-80% of complete limb occlusion pressure for the BFR intervention and only 10% for the Sham intervention group. This was automatically calculated by the BFR (MadUP©, France). Results showed a significant pain reduction in step-down, shallow and deep single leg squat tests from baseline to post-BFR evaluation on day 1 and 2, this pain reduction sustained for 45 minutes from baseline at the post physiotherapy evaluation. On the contrary, no significant pain reduction during step down and shallow single leg squat tests in the sham BFR group on both days, however, significant pain reduction in deep single leg squat evaluation on day 2 prior to intervention was reported. No significant differences were detected when PPTs were measured proximally or distally to the site of applied BFR. Rating of perceived exertion showed a greater rating following BFR intervention when compared to a sham intervention. As a conclusion, high pressure BFR training was reported to have an immediate pain-reducing effect on the three functional tests included in the study.