Restoring Biomechanical Gait Function with Ultrasound-Guided Acupotomy for Post-Stroke Equinovarus Foot: Two Case Reports and a Protocol (A CARE- and SPIRIT-Compliant Study)

Abstract

Background: Post-stroke equinovarus foot (EVF) impairs gait stability, increases the risk of secondary injuries, and contributes to elevated healthcare costs. However, effective targeted interventions for EVF remain limited.

Patient concerns: Two patients with chronic EVF-a 63.5-year-old male (9.7 months post-stroke) and a 35.7-year-old female (24.5 months post-stroke)-presented with ankle deformity, gait asymmetry, and impaired balance, all of which interfered with daily activities.

Intervention and outcomes: Both patients underwent ultrasound-guided acupotomy targeting spastic ankle muscles, administered over four sessions within two weeks. A quantitative gait analysis revealed substantial improvements in step length ratios (Case 1: 0.61 → 0.86; Case 2: 0.67 → 0.88), as well as enhancements in walking velocity, lateral symmetry, postural balance, and Modified Ashworth Scale scores. No adverse events were reported. Protocol proposal: Based on these observations, a prospective randomized controlled trial is planned to compare ultrasound-guided acupotomy plus conventional therapy versus conventional therapy alone. Outcomes will be assessed quantitatively using gait analysis. Lessons and implications: Ultrasound-guided acupotomy may offer a minimally invasive, targeted approach to releasing spastic muscles while preserving neurovascular structures, thereby improving gait function in patients with post-stroke EVF.

Keywords: case report; equinovarus foot; protocol; stroke; ultrasound-guided acupotomy.

Figure 1

Clinical photographs and corresponding ultrasound images demonstrating the ultrasound-guided acupotomy procedures targeting the medial and lateral heads of the gastrocnemius, soleus (a), and tibialis posterior (b) muscles. In each panel, the left image shows the probe placement on the patient’s lower limb, and the right image presents the transverse ultrasound scan obtained using an in-plane approach. During the procedures, the acupotomy needle was inserted parallel to the orientation of the muscle fibers and manipulated up to three times at each insertion site. (a) Pathways 1 and 2 represent the insertion trajectories targeting the medial and lateral gastrocnemius heads (GN MHs and GN LHs) and the soleus (SOL) muscle, respectively. (b) Pathways 3 and 4 depict the insertion pathways through the soleus (SOL) muscle to access the tibialis posterior (TP) muscle. The choice of insertion pathway was determined based on the relative location of the neurovascular bundle (*), ensuring safe needle placement during the procedure. GN MH, gastrocnemius medial head; GN LH, gastrocnemius lateral head; SOL, soleus muscle; FDL, flexor digitorum longus; FHL, flexor hallucis longus; T, tibia; TP, tibialis posterior; *, neurovascular bundle.

Figure 2

Changes in gait, balance, and spasticity variables before and after ultrasound-guided acupotomy in two stroke patients. While improvements in gait symmetry and balance during standing were observed, no significant differences in the Modified Ashworth Scale (MAS) scores were noted for either case. To facilitate interpretation, the larger value was consistently used as the denominator when calculating the step length ratio. For lateral symmetry, values are expressed as positive (+) when the center of pressure (COP) shifted toward the unaffected side and as negative (–) when shifted toward the affected side, using the midline as the reference. Red arrows (▲ and ▼) indicate increases and decreases in values, respectively. These arrows do not imply clinical improvement or deterioration, as interpretation depends on the specific variable.

Figure 3

Timeline of post-stroke duration and treatment sessions for the two cases. Cases 1 and 2 had elapsed durations of 9.7 and 24.5 months, respectively, since stroke onset, both exceeding the conventional rehabilitation period. Each patient received four sessions of ultrasound-guided acupotomy on Days 1, 5, 10, and 14. Quantitative gait and balance evaluations were conducted twice: immediately before the first treatment (Day 1) and after the final treatment (Day 14). The red arrow indicates the chronological progression of time across the treatment period. US, ultrasound.

Figure 4

Study flow diagram. SCR, screening. Arrows indicate the chronological flow of the study procedures. Text in red highlights interventions that were administered exclusively to the intervention group and not to the control group. Circles indicate that the corresponding intervention or evaluation was performed on that specific visit day.

Figure 5

Procedures for infection prevention. To prevent infection, a sterile disposable surgical contact drape (3M Steri-Drape^TM, model 1050, St. Paul, MN, USA) was applied to the ultrasound probe prior to the procedure (a). The treatment area was then disinfected twice: first with an alcohol swab (left image) and then with povidone–iodine (right image) (b).