Neuromotor Treatment of Arthrogenic Muscle Inhibition After Knee Injury or Surgery

Abstract

Background: Persistent weakness of the quadriceps muscles and extension deficit after knee injuries are due to specific alterations in neural excitability - a process known as arthrogenic muscle inhibition (AMI). The effects of a novel neuromotor reprogramming (NR) treatment based on the use of proprioceptive sensations associated with motor imagery and low frequency sounds have not been studied in AMI after knee injuries.

Hypothesis: This study aimed to assess quadriceps electromyographic (EMG) activity and the effects on extension deficits in persons with AMI who completed 1 session of NR treatment. We hypothesized that the NR session would activate the quadriceps and improve extension deficits.

Study design: Case series.

Level of evidence: Level 4.

Methods: Between May 1, 2021 and February 28, 2022, patients who underwent knee ligament surgery or sustained a knee sprain with a deficit of >30% of the vastus medialis oblique (VMO) on EMG testing in comparison with the contralateral limb after their initial rehabilitation were included in the study. The maximal voluntary isometric contraction of the VMO measured on EMG, the knee extension deficit (distance between the heel and the table during contraction), and the simple knee value (SKV) were assessed before and immediately after completion of 1 session of NR treatment.

Results: A total of 30 patients with a mean age of 34.6 ± 10.1 years (range, 14-50 years) were included in the study. After the NR session, VMO activation increased significantly, with a mean increase of 45% (P < 0.01). Similarly, the knee extension deficit significantly improved from 4.03 ± 0.69 cm before the treatment to 1.93 ± 0.68 after the treatment (P < 0.01). The SKV was 50 ± 5.43% before the treatment, and this increased to 67.5 ± 4.09% after the treatment (P < 0.01).

Conclusion: Our study indicates that this innovative NR method can improve VMO activation and extension deficits in patients with AMI. Therefore, this method could be considered a safe and reliable treatment modality in patients with AMI after knee injury or surgery.

Clinical relevance: This multidisciplinary treatment modality for AMI can enhance outcomes through the restoration of quadriceps neuromuscular function and subsequent reduction of extension deficits after knee trauma.

Keywords: arthrogenic muscle inhibition; knee; neuromotor reprogramming.

Figure 1.

Technique for measuring knee extension deficit. (a) Distance between the heel and the table (DHT) during VMO contraction and holding the heel up (black arrow). (b) Distance between the popliteal fossa and the wall (DPW) during stand-up position (white arrow).

Figure 2.

Description of neuromotor reprogramming.

Figure 3.

Mean EMG change for the injured and uninjured limbs during maximum voluntary isometric contraction. (a) Mean EMG changes across individual patients. (b) Mean EMG increase at the group level. Positive values indicate an increase of VMO activity after intervention compared with baseline. EMG, electromyographic; VMO, vastus medialis oblique.

Figure 4.

Barplots with 95% CIs (error bars) of extension deficit measurements before and after NR. (a) DHT during VMO contraction and holding the heel up. (b) DPW during stand-up position. *P < 0.05, ***P < 0.01. DHT, distance between the heel and the table; DPW, distance between the popliteal fossa and the wall; NR, neuromotor reprogramming; NS, not statistically significant; VMO, vastus medialis oblique.

Figure 5.

Scores of self-reports on knee function (SKV) before and after NR session. Error bars, 95% CI; P < 0.01. NR, neuromotor reprogramming.