Changes in Maximal Isometric Quadriceps Strength after the Application of Ultrasound-Guided Percutaneous Neuromodulation of the Femoral Nerve: A Case Series

Abstract

Abstract Introduction For those individuals who have suffered an injury to the knee or undergone a surgical intervention, the early recovery of the muscle strength contraction properties of the quadriceps is essential for a favorable recovery and for a return to the activities of daily living and other work- or sports-related activities. Objectives To evaluate the changes in maximal isometric strength (MIS) of the quadriceps muscle after the application of ultrasound-guided percutaneous neuromodulation (US-guided PNM) on the femoral nerve. Materials and Methods A case series involving subjects who had previously presented unilateral knee pathology and were in the stage of recovery of quadriceps strength. The subjects were pain-free at the time of the dynamometry measurements, which were performed before and after the application of the US-guided PNM technique. The isometric measurement was performed using the KINEO dynamometry system, performing a preintervention measurement of the mean maximal isometric strength (mMIS) based on 3 repetitions (3 seconds contraction and 6 seconds relaxation). The US-guided PNM technique was performed on the femoral nerve, using the Physio Invasiva CE0120 device (Prim Physio, Madrid, Spain) and a GE Logiq e R7 ultrasound (GE Healthcare, Chicago, IL, USA). Results In total, 13 subjects participated in the present study. Significant changes were obtained (p < 0.001) in the mMIS of the quadriceps of the affected knee, which progressed from a mean strength of 25.91 kg (standard deviation [SD]: 7.17 kg) to a mean strength of 29.98 kg (SD: 9.06 kg). Discussion In subjects with knee pathology, the quadriceps muscle is inhibited despite being pain-free during the strength measurements. This process of inhibition can improve with the application of low frequency percutaneous electrical stimulation on the femoral nerve. This technique represents a complementary strategy for the recovery of the normal strength values in pathological knees with or without prior surgery. Conclusions Ultrasound-guided PNM is an effective technique for the reestablishment of quadriceps strength in inhibited muscles.