June 20, 2021
Progressive Tendon-loading Exercises Vs Eccentric Exercise Therapy in Patellar Tendinopathy cover

Paper Review:Progressive Tendon-loading Exercises Vs Eccentric Exercise Therapy in Patellar Tendinopathy

Patellar tendinopathy (PT), often termed jumper’s knee, is a common cause of knee pain in running and jumping sports. It is the most common overuse injury of the knee extensor mechanism. Although it can occur acutely, it is classically considered an overuse injury due to repetitive microtrauma. Common sports include basketball and volleyball where up to 45% of athletes suffer from PT (Lian 2005). The diagnosis is primarily clinical based on pain and tenderness at the inferior pole of the patella. Treatment is centered around activity modification, medications and physical therapy.

Case vignette

You are evaluating a 17 year old volleyball athlete with patellar tendinopathy. She is point tender on the inferior pole of the patella with an intact extensor mechanism. You want to ultrasound her patellar tendon to help confirm your diagnosis. Which of the following are you most likely to see?

A) Joint effusion with increased signal of hoffa fat pad
B) Thickened tendon with hypoechoic areas
C) Large hypoechoic area with discontinuity of fibers
D) Hypoechoic mass within the tendon

In this week’s blog post, we review a study by Breda et al comparing progressive tendon loading exercises to eccentric exercise therapy in patients with PT.
concentric eccentric isometric exercise ilustration

Image 1. Illustration of concentric, eccentric and isometric exercise (courtesy of wodconnect)

Physical therapy for PT has classically focused on eccentric exercise therapy (EET). Eccentric exercises involve tendon lengthening, while concentric involves shortening of the tendon fibers. Eccentric exercises have been shown to be superior to concentric exercises (Jonsson 2005). Progressive tendon loading exercises (PTLE) has been proposed as an alternative therapy for PT but it is currently unknown how PTLE compares to EET (Malliaras 2015).
The authors performed an investigator blinded, block randomized trial of 76 patients with clinically and ultrasound confirmed PT. They were randomly assigned to PTLE or EET. PTLE exercises involved 4 stages progressing from isometric (stage 1), isotonic (stage 2), explosive (stage 3), sport specific (stage 4). EET involved single leg decline squats followed by sports specific exercises. The outcome of interest at 24 weeks was the Victorian Institute of Sports Assessment for patellar tendons (VISA-P) questionnaire measuring pain, function and ability to play sports. Secondary outcomes included the return to sports rate, subjective patient satisfaction and exercise adherence.
patellar tendinopathy rehab protocol

Image 2. Visual depiction of progressive tendon-loading exercise and eccentric exercise protocol (Breda et al)

The average age was 24, 76% were male with an average of 2 years of PT symptoms. 82% had previously undergone treatment for PT but failed to recover. Improvements in the VISA-P scoring were significantly higher for PTLE compared to EET at 24 weeks (28 vs 18 points, adjusted mean between-group difference, 9 (95% CI 1 to 16); p=0.023). There was also a trend towards a higher return to sport in the PTLE group. Patients in the PTLE group tended to have less pain with the exercises and trended towards higher satisfaction scores. This was true despite the chronicity of symptoms and previous conservative treatment.

Summary

Somewhat surprisingly, PTLE provided superior clinical outcomes compared to EET at 24 weeks. This is significant because EET is commonly used in clinical practice and is included in most tendinopathy management guidelines. PTLE also trended towards a higher rate to play than EET, less pain with the protocol and higher satisfaction scores. Ultimately, we need bigger and better studies to see if PTLE truly is superior for PT, but this initial study is promising. PTLE should be part of a conservative management protocol for PT. It will also be curious to find out if the same concept applies to other tendinopathies where EET is considered the standard.

Case Conclusion

Answer B. Diagnostic ultrasound of patellar tendinopathy should show a thickened but intact tendon. There may be areas of hypoechoic tissue and increased signal on collar doppler. Joint effusion and hyperechogenicity of hoffa fat pad should not be seen in patellar tendinopathy. Discontinuity of fibers and a large hypoechoic area is something you would expect with patellar tendon rupture. A hypoechoic mass can be seen with enthesophytes, gout or even potentially apophysitis of the inferior pole, none of which fit the clinical vignette.

Rodriguez-Merchan, E. Carlos. “The treatment of patellar tendinopathy.” Journal of Orthopaedics and Traumatology 14.2 (2013): 77-81.

References

  1. Lian, Østein B., Lars Engebretsen, and Roald Bahr. “Prevalence of jumper’s knee among elite athletes from different sports: a cross-sectional study.” The American journal of sports medicine 33.4 (2005): 561-567.
  2. Jonsson P, Alfredson H. Superior results with eccentric compared to concentric quadriceps training in patients with jumper’s knee: a prospective randomised study. Br J Sports Med. 2005;39:847-850
  3. Malliaras, Peter, et al. “Patellar tendinopathy: clinical diagnosis, load management, and advice for challenging case presentations.” journal of orthopaedic & sports physical therapy 45.11 (2015): 887-898.

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