Poster 207: Muscle Activation in Postoperative Ambulation Protocols Following Proximal Hamstring Tendon Repair
Authors: Athanasian Christian , Czerwonka Natalia , Reynolds Alan , Mather Richard C. , Christian Robert A. 
Published: August 2024

Objectives:

Postoperative rehabilitation protocols for patients undergoing proximal hamstring tendon repair have not been explored extensively. There is no consensus regarding the optimal rehab protocol and bracing strategy to protect the surgical repair. Herein, we have tested for the optimal postoperative weight-bearing and bracing protocol utilizing novel transcutaneous electromyography (EMG) technology.

Methods:

Healthy volunteers without any history of hip or knee surgery were included in this study. Participants first walked a standardized distance with Myontec Mbody 3 shorts, and then completed the following over the same standardized distance with crutches: flat foot weightbearing (FFWB), FFWB with a Newport abduction hip brace restricting motion past 90 degrees of flexion, FFWB with an unlocked hinged-knee brace, hinged-knee brace locked in 90 degrees of flexion, hinged-knee brace locked in 60 degrees of flexion, and hinged-knee brace locked in 30 degrees of flexion. Each condition was tested on both right and left extremities. Ipsilateral and contralateral quadricep, hamstring, and gluteal group muscle activation were measured. Data from each trial were standardized with the walking trial muscle activation as the reference. Primary outcome measures were normalized cumulative muscle group activation and normalized maximal muscle group activation.

Results:

ANOVA testing across the different trials demonstrated a statistically significant difference between means of ipsilateral hamstring standardized cumulative muscle activation (p= 0.00128) and means of ipsilateral hamstring standardized peak muscle activation (p= 0.00231). Tukey test of Honestly Significant Differences demonstrated significant differences between hinged-knee brace locked at 90 degrees and hinged knee brace locked at 30 degrees (p=0.0399208), and hinged-knee brace locked at 90 degrees and FFWB with unlocked hinged-knee brace (p=0.0235594) for normalized cumulative muscle activation. Significant differences were noted for normalized peak muscle activation between hinged-knee brace locked at 60 degrees and FFWB (p=0.0188864), hinged-knee brace at locked at 60 degrees and FFWB with a hip brace restricting motion past 90 degrees of flexion (p=0.0314595), and hinged-knee brace at 60 degrees and FFWB with hinged-knee brace unlocked (p=0.0046806).

Conclusions:

Statistically significant differences were noted in cumulative muscle activation and peak muscle activation between trials involving FFWB (including no brace, a hip brace, and an unlocked knee brace) and trials involving hinged-knee braces locked in a high degree of flexion, with better outcomes trials involving FFWB. No significant differences were noted between FFWB trials involving no brace or the use of a brace. Postoperative bracing may not be necessary, with FFWB without the use of a brace appearing to be a viable option for patients. [Figure: see text][Figure: see text]