How often do you utilize NMES? For a while we have known the efficacy of NMES on quads strength in various patient populations, ranging from post-operative TKA to ACL patients. NMES can be a useful tool to allow early recruitment of the quadriceps muscle, especially in those with inhibition. Typically, NMES is utilized while performing quad sets in order to improve contraction and activation. This study , however, looks at NMES superimposed on a sit-to-stand-to-sit (STSTS) movement in the ACL reconstruction patient population to not only improve strength, but to also improve loading through the affected limb as this can be a significant deficit in return to sport criteria.
The inclusion criteria include the following:
- Males with unilateral ACLR
- Ages: 18 – 40 years
- Patellar tendon graft (performed via the same surgeon)
- 90* knee flexion (at 15 days post-op)
- Physical Activity level: 7-10 (via Tegner scale)
The exclusion criteria include the following:
- Prior injury of the affected limb
- Injury to other ligaments (meniscal repairs were included in the trial)
- VAS scores that prevented the subject from performing STSTS movements
A standard rehabilitation protocol was followed as noted by the outline below:
- Prior to initiation of the NMES/STSTS protocol (post-operative day 15) the following were implemented:
- NMES: low frequency/high volume
- Day 2 weight-bearing initiation
- Isometric straight leg raises (through 1 month)
- At 3-4 weeks post op the following were implemented:
- Water exercises: cycling, stepping, walking
- Squatting Exercises
- At month 2, strengthening exercises were then incorporated. Through months 3-6 strengthening and power exercises were added along with sports specific training.
The following groups were created for the trial (50 total participants): 1) NMES with STSTS movements 2) STSTS movements only 3) No Additional Treatment. Treatment was carried out 5 days/week from Day 15 – Day 60.
NMES with STSTS Group:
- For the NMES group, treatment was applied at 35 and 50 Hz (alternating days) to address both slow and fast-twitch fibers with intensity (max intensity: 120 mA) increasing as patient tolerated at each repetition of each session.
- Duty Cycle: 16 seconds (8″ on/8″ off)
- Day 15-20: 3 sets, 6 reps
- Day 20-45: 3 sets, 10 reps
- Day 45-60: 3 sets, 12 reps
- Knee extensor and flexor maximal isometric voluntary contraction was measured at 60 and 180 days post-operative. Knee extensors were measured at 30 and 90 degrees, knee flexors at 90*.
- Lower extremity loading was measured via force plates with a STSTS movement at 15, 30, 60, and 180 days post-operative. A jump was added at the 180 testing only.
- Thigh circumference was analyzed at post-operative days 15, 30, 60, and 180 days.
- STSTS + NMES: higher knee extensor forces generated at 60 & 180 days post-operative
- STSTS + NMES: higher knee flexor forces generated at 60 days post-operative
- Limb Symmetry:
- STSTS + NMES: higher limb symmetry index at 30 days post-operative compared to day 15
- STSTS + NMES: Higher limb symmetry index at 60 days post-operative compared to STSTS group
- STSTS + NMES: Higher limb symmetry index at 30, 60, 180 days post-operative compared to NAT group
- Girth Measurements:
- Thigh circumference: Lower between-limb difference at 30, 60, 180 days post-operative compared to both STSTS and NAT groups
This study suggests improved quadriceps activation, hypertrophy, and lower extremity loading with the use of NMES superimposed on functional movements as another great tool to add to the ACL rehabilitation patient. How often do you, or your clinical instructor, employ NMES in the post-operative patients.