The post-operative rehabilitation of an ACL reconstruction is something that many sports physiotherapists perform on a daily basis. Many will know that muscular atrophy is quite common; particularly affecting the quadriceps, hamstrings and triceps surae. In fact, quadriceps atrophy and strength will often exceed 20% during the first three months (Nicholas et al., 2001). Therefore, we see post-operative rehabilitation protocols focusing on quick restoration of the patients muscle function and strength. Thus, we are often quick to, appropriately so, prescribe exercises.
However, of course there is the potential for the additional clinical utility of electrical muscle stimulation (electro-stimulation). This is something that I utilise in my clinic given the previously identified benefits to strength following ACL reconstruction (Hasegawa et al., 2011), however, I have been unsure of any benefits to ROM or joint effusion/swelling. This is because the effect of early electro-stimulation on joint effusion-swelling and pain recovery after anterior cruciate ligament reconstruction has not yet been evaluated. However, a new pilot study has given us some promising results…
New Research On Electro-Stimulation Following ACL Reconstruction
Ediz et al (2012) have evaluated the impact of the addition of electro-stimulation to normal post-operative rehabilitation following ACL reconstruction in 28 patients. The aim of the study was to assess the effects of 30 sessions (i.e. 5 days a week for 6 weeks) of electro-stimulation on effusion, swelling, pain recovery, range of motion and muscle atrophy.
The patients were divided into 2 groups, the first undergoing exercise based rehabilitation and icing for the first 6 weeks. The second group had the addition of electro-stimulation (frequency of 30 Hz, pulse width of 300 ms with a duty cycle of 10s on and 20s off for a period of 20 min, 30 sessions, five consecutive days in each week for six weeks).
So, What Did They Assess?
The authors evaluated the following outcomes:
- Effusion: graded as 3 (>60 cm3 – tight capsule), 2 (25–60 cm3 – visible), 1 (<25 cm3 – palpable by smoothing out the joint capsule), or 0 (no effusion).
- Swelling: circumference was measured at the mid-centre of the patella to assess swelling. The contralateral, non-operated knee served as a control. Differences in circumferences between operated and non-operated knees were used as measurement of swelling.
- Pain: resting pain was documented using a visual analogue scale
- ROM and Extension Deficit: using standard goniometric assessment
- Thigh Atrophy: circumference was measured at 10 cm proximal to the upper patellar margin and 10 cm distal to tibial tuberosity to determine atrophy. Interestingly, it has been shown that this measurement correlates significantly with isokinetic strength testing (Jaervelae et al., 2002).
- Functional Measures: scored using the International Knee Documentation Committee scoring system and Tegner Activity Scale.
And, What Did They Find?
Well, if I could sum it up in just one sentence: the results were small but positive. The authors found the following results:
- Effusion and Swelling: after one week the electro-stimulation group had significantly less effusion and swelling. The results were similar up to the 12 week mark.
- Pain: the electro-stimulation had significantly lower visual analogue scale scores from seven days up to 12 weeks postoperatively.
- Extension Deficit: mean differences in extension deficit at 14 days, eight weeks and 12 weeks proved significant in favour of the electro-stimulation group.
- Muscle Atrophy: there were significant differences between the groups at 14 days and eight weeks of the treatment
- Functional Measures: at the 12 week mark (but at no other point) the mean International Knee Documentation Committee subjective knee score was significantly greater in electro-stimulation group.
Limitations of The Research
There are quite a few limitations to the study, many of which the authors are fully aware. These include:
- Small sample size, but this is a pilot study
- Questionable validity and reliability of some outcome measures utilised e.g. joint effusion-swelling has not been assessed by a radiologic method such as ultrasound or magnetic resonance imaging
- No use of sham or placebo treatment
- High dosage (30 treatments in 6 weeks) utilised affects the generalisability to many clinical settings
- The outcome assessor was not blinded to the patient groups
Clinical Implications of This Research
Quite simply, the addition of electro-stimulation initiated four days after anterior cruciate ligament reconstruction surgery can provide more decreases in effusion, swelling, pain, extension deficit and can prevent muscle volume loss greater than exercise alone. Whilst statistically significant, the results shown in this pilot study were quite modest. However, as we can appreciate has the potential to positively influence and accelerate the rehabilitation process. If you are dealing with athletes who want the quickest recovery possible (which would be nearly 100% of mine) then this is an option worth considering.
What Are Your Thoughts?
What are your thoughts on this new pilot study. Do you effectively use electro-stimulation in your practice? If so (or if NOT) be sure to let me know in the comments or catch me on Facebook or Twitter.
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Photo Credit: snowpeak
Ediz L, Ceylan MF, Turktas U, Yanmis I and Hiz O. A randomized controlled trial of electrostimulation effects on effussion, swelling and pain recovery after anterior cruciate ligament reconstruction: a pilot study. Clin Rehabil 2012;26(5): 413
Eriksson E, Haggmark T, Kiessling KH and Karlsson J. Effects of electrical stimulation on human skeletal muscle. Int J Sports Med 1981; 2: 18–22.
Hasegawa S, Kobayashi M, Arai R, Tamaki A, Nakamura T and Moritani T. Effect of early implemen- tation of electrical muscle stimulation to prevent muscle atrophy and weakness in patients after anterior cruciate ligament reconstruction. J Electromyogr Kinesiol 2011; 21: 622–630.
Jaervelae T, Kannus P, Latvala K and Jaervinen M. Simple measurements in assessing muscle performance after an ACL reconstruction. Int J Sports Med 2002; 23: 196–201.
Nicholas SJ, Tyler TF, McHugh MP and Gleim GW. The effect on leg strength of tourniquet use during anterior cruciate ligament reconstruction: a prospective random- ized study. Arthroscopy 2001; 17: 603–607.