NEUROMUSCULAR ELECTRICAL STIMULATION (NMES) REHABILITATION PROTOCOL FOR SURGICALLY TREATED ACHILLES TENDON RUPTURE (EVALUATION AND IMPROVEMENT)

Open Access
- Author:
- Rahimnezhad Baghche Jooghi, Shabnam
- Graduate Program:
- Mechanical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 02, 2024
- Committee Members:
- Robert Kunz, Professor in Charge/Director of Graduate Studies
Jason Moore, Major Field Member
Meghan Vidt, Outside Unit & Field Member
Daniel Cortes Correales, Chair & Dissertation Advisor
Reuben Kraft, Major Field Member - Keywords:
- Neuromuscular Electrical Stimulation Rehabilitation
Achilles Tendon Rupture
Calf Muscle Volume Estimation
Muscle Deficits Post-Injury
Magnetic Resonance Imaging (MRI)
Diffusion Tensor Imaging (DTI) - Abstract:
- The Achilles tendon (AT), the strongest tendon in the human body, transmits the contraction forces of the gastrocnemius and soleus muscles to the calcaneus. Due to excessive loading and limited vascular supply, AT is particularly susceptible to degenerative conditions and ruptures. Recovery from an Achilles tendon rupture (ATR), whether treated conservatively or surgically, can take up to a year, with many patients failing to regain pre-injury performance fully. Long-term complications often include muscle atrophy, increased fat infiltration, and permanent alterations in the structural and mechanical properties of the tendons. Current rehabilitation protocols remain inadequate, primarily because of a limited understanding of tendon biology and scarring processes. This dissertation evaluated neuromuscular electrical stimulation (NMES) as an adjunct to conventional ATR rehabilitation. We introduce a novel NMES protocol with specified parameters and provide documented and video implementation instructions. Using a REDCap environment, we collected data over six weeks on applied load, daily steps, and pain levels, while also assessing patient-reported outcomes at weeks 6 and 12. On week 6 and week 12, we performed an ultrasound evaluation and finally at week 12 we performed a heel-rise test on the participants. One requirement of this study was to measure muscle volume during routine evaluations. To achieve this, ultrasound-based calf muscle estimations were suggested and validated by recruiting 12 healthy subjects and 10 recovered patients, providing data on a total of thirty legs. Validation was performed using leave-one-out cross-validation (LOOCV). Preliminary results from a randomized evaluation of six participants suggested that NMES may effectively reduce muscle atrophy, although this alone does not guarantee improved functional performance. This raises further questions regarding additional factors that influence recovery after ATR. In the second phase of the study, we aimed to gain a deeper understanding of the long-term changes and challenges experienced by patients with ATR beyond what is currently acknowledged in the literature. To achieve this, ten participants were studied: two who had undergone surgery within the past six months and eight who had surgery more than a year and a half ago. Imaging techniques, including magnetic resonance imaging (MRI) (T1 structural and Diffusion Tensor Imaging (DTI)) and ultrasound (US), have been used to assess persistent changes in muscle structures, focusing on fatty infiltration and fibrosis at the distal end of the soleus muscle. The findings of this study offer valuable insights into the possible causes and characteristics of fatty infiltration after ATR surgery, potentially informing future surgical techniques and enhancements in postoperative care. While the sample size for the first aim was limited, making it difficult to draw definitive conclusions about the benefits of NMES in rehabilitation protocols, all participants completed the study without experiencing any adverse effects related to NMES. This finding suggests its feasibility as an adjunct therapy for ATR rehabilitation. Additionally, we developed an analytical method utilizing ultrasound data to estimate the muscle volumes of the gastrocnemius (R² = 0.93) and soleus (R² = 0.92), furthering our understanding of muscle adaptations after ATR. This approach can serve as a valuable procedure for routine evaluation of treatment efficacy following ATR.