Reviewed by Mark Boyland PT, DPT, CSCS

Knee osteoarthritis is a common condition that produces pain and limits patient function.  Patients are regularly referred to Physical Therapy for complaints related to knee osteoarthritis and practice guidelines indicate exercise therapy should be the primary emphasis in the treatment of knee osteoarthritis.  The authors were well aware and sought to compare two exercise types and their effect on patient’s knee pain.

Patients included in the trial were of 50 years age and up, able to walk without an assistive device, and has x-ray findings noting knee osteoarthritis.  The study had 86 patients complete the study.  There were 42 participants who completed the hip abductor and quadriceps strengthening protocol and 44 participants in the quadriceps strengthening protocol only.  Participants completed the Knee Injury and Osteoarthritis Outcomes Scores (KOOS) throughout the study.

The exercise protocol explored only two exercises.  The quadriceps strengthening group performed a knee extension exercise again for 4 sets of 10 with a 10 second hold at the top of the motion, performed in the morning and in the evening.  The hip abductor strengthening group performed 4 sets of 10 of sidelying hip abduction with a 10 second hold at the top as well as the quadriceps strengthening exercise, performed in the morning and in the evening. The patients added a weight as needed to increase the difficulty as directed by the study design.  The patients began with 50% of their 10 rep maximum for weeks 1 and 2, 60% for weeks 2-4, 70% for weeks 4-6, 80% for weeks 6-8, and 90% weeks 8-10. 

Both study groups had improvements in their KOOS scores every 2 weeks.  At the 10 week mark participants had at a minimum of 9.09% of improvement on the symptoms KOOS subsection up to 27.09% improvement in regards to quality of life.  On average there was a 17.98% improvement across all subsections of the KOOS regardless of the group participants were placed in.

What can this mean for my patients? I attempted the 4 sets of 10 for 10 second holds with a 3 lb ankle weight and found it relatively challenging for myself and starting with a lighter weight was likely recommended.  If my patients can tolerate this exercise protocol they only need to do 1 exercise for about 20 minutes per day.  If my patients crave a little more variety they could do two exercises which would take about 40 minutes per day.  The authors note that further studies need to be completed and that this may have been a relatively small sample size but I think most of my patients would be quite pleased with a minimum 9% improvement in the pain, function, and quality of life with just 1 exercise even if it could take up to 10. 

doi: 10.1186/s12891-020-03316-z.