Effectiveness of Shockwave Treatment Combined With Eccentric Training for Patellar Tendinopathy: A Double-Blinded Randomized Study
Karin M. Thijs, Johannes Zwerver, Frank J. G. Backx, Victor Steeneken, Stephan Rayer, Petra Groenenboom, Maarten H. Moen.
Clinical Journal of Sport Medicine, Volume 27, No. 2, May 2017
Patellar tendinopathy is a common overuse injury that affects the origin of the patellar tendon at the inferior pole of the patella. Overload of the mechanism leads to pain and dysfunction, and this condition can become chronic and difficult to treat. While eccentric training has developed a standard role in the rehabilitation for patellar tendinopathy, the role of extracorporeal shockwave therapy (ESWT) is less understood. The goal of this study was to determine the effectiveness of a combined treatment of eccentric training and ESWT compared with eccentric training and sham shockwave (placebo) in participants with patellar tendinopathy over a 24-week follow-up period.
This multicenter randomized and placebo-controlled trial was conducted at sports medicine departments in a university hospital and general hospital in the Netherlands. Fifty-two physically active male and female participants (mean age 28.6 years, range 18-45) with a clinical diagnosis of patellar tendinopathy were randomly allocated to either eccentric exercises with ESWT (ESWT group), or eccentric exercises in combination with sham-shockwave therapy (placebo group). Extracorporeal shockwave therapy and sham shockwave were applied in 3 sessions at 1-week intervals with a piezoelectric device. All participants in the study were instructed to perform eccentric exercises on a decline board at home (3 sets of 15 repetitions, twice per day). To assess outcomes, the Victorian Insitute of Sport Assessment-Patella (VISA-P) scores, pain scores during functional knee loading tests, and Likert scores were registered at baseline, 6, 12, and 24 weeks after initiating the ESWT or sham-shockwave treatment.
The results of the study revealed that when comparing the ESWT group to the placebo group, there ware no significant differences found. While VISA-P and pain scores significantly improved over the study period, there was no treatment effect between the groups over time.
Despite being a double-blinded, randomized control trial study, the authors note several limitations in their work. The power analysis prior to the start of the study revealed that 56 patients were needed to detect a clinically significant difference in the VISA-P score of 15 points. Unfortunately, there was a large loss to follow-up (31.8% in the ESWT and 13.3% in the placebo groups respectively). Furthermore, the physical therapists that performed the treatments were unblinded (as they needed to adjust the shockwave device to “true” or “sham” treatment), and this could have influenced the results. With these limitations in mind, this study showed no additional benefit of 3 sessions of ESWT in patients with patellar tendinopathy.
Sean Mindra, MD, CCFP
PGY3 – Sport and Exercise Medicine, University of Ottawa
Advisor: Dr. Taryn Taylor BKin, MSc, MD, CCFP (SEM), Dip Sport & Exercise Medicine