Can Ultrasound Therapy Effectively Treat Knee Osteoarthritis?

Warren Han, Mercer University College of Pharmacy

According to the Arthritis Foundation, osteoarthritis is a degenerative joint disease caused by the damage or break down of cartilage leading to inflammation and bone pain. Weight management, stretching, anti-inflammatory and anti-pain medications, physical and occupational therapy, and surgery have been recommended as treatment strategies. [1]

A review of therapeutic ultrasound for osteoarthritis that used sound waves to relieve pain and disability suggested best results occur after two to eight weeks of treatment. [2] The American Academy of Orthopedic Surgeons (AAOS) guideline for the treatment of osteoarthritis of the knee stated that it was neutral on the use electrotherapeutic modalities or other physical agents due to inconclusive data. [3]

Efficacy of focused low-intensity pulsed ultrasound therapy for the management of knee osteoarthritis: a randomized, double blind, placebo-controlled trial [4]
Design Randomized, double-blind, placebo-controlled; N= 106
Objective To investigate the effects of focused low-intensity pulsed ultrasound (FLIPUS) therapy on functional and health status of patients with knee osteoarthritis (OA)
Study Groups Group I: FLIPUS + diclofenac sodium (n= 53)

Group II: placebo FLIPUS + diclofenac sodium (n= 53)

Methods No physiotherapy and pharmacotherapy were given prior to ultrasound (US) treatment to either of the groups.  Ultrasound treatment was applied to both sides of the knee.  Group I received FLIPUS for 20 minutes once daily, and group II received a placebo treatment (without energy output) for 20 minutes.  All patients received diclofenac sodium tablets once daily for the entire 10-day treatment period.  Outcomes were measured after 10 days of treatment, and follow-ups were conducted at week 4 and 12.  The visual analog scale (VAS) measured knee pain on movement for 5 minutes, the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) scores were used to measure knee functional ability, and the Lequesne Index (LI) score were used to measure disability.
Duration February 2015 to February 2016
Primary Outcome Measure VAS pain, WOMAC scores, and LI scores
Baseline Characteristics FLIPUS + diclofenac sodium Placebo FLIPUS + diclofenac sodium p-value
Male/female, n 14/39 16/37 0.666
Mean age, yrs ± SD 63.42 ± 9.73 61.34 ± 10.25 0.774
BMI, kg/m2 ± SD 25.79 ± 3.46 26.17 ± 5.92 0.568
Mean duration of knee OA, months ± SD 140.36 ± 87.32 137.45 ± 92.48 0.532
Mean systolic blood pressure, mmHg ± SD 125.65 ± 8.25 126.35 ± 9.79 0.676
Mean diastolic blood pressure, mmHg ± SD 75.45 ± 7.85 76.38 ± 7.78 0.725
Mean glucose, mmol/L ± SD 9.59 ± 8.24 9.69 ± 7.87 0.458
Results Baseline Endpoint Between-group difference
Group I

 

 

Group II Group I Group II Mean (95% CI) p-value
Mean VAS ± SD 6.98 ± 1.06 6.76 ± 1.02 1.54 ± 0.81 2.28 ± 1.01 N/A 0.000
VAS mean change from baseline ± SD, (95% CI) N/A N/A 5.44 ± 0.84 (5.05 to 5.79) 4.48 ± 0.84 (4.08 to 4.88) 0.96 (0.63 to 1.29) 0.000
Mean WOMAC ± SD 44.34 ± 10.79 42.42 ± 9.39 10.92 ± 8.57 15.88 ± 5.26 N/A 0.001
WOMAC mean change from baseline ± SD, (95% CI) N/A N/A 33.42 ± 7.99 (29.55 to 37.29) 26.54 ± 5.85 (23.52 to 29.56) 6.88 (4.10 to 9.66) 0.000
Mean LI ± SD 7.56 ± 2.73 7.10 ± 2.12 1.82 ± 1.44 2.66 ± 1.12 N/A 0.000
LI mean change from baseline ± SD, (95% CI) N/A N/A 5.74 ± 1.99 (4.87 to 6.61) 4.44 ± 1.39 (3.57 to 5.02) 1.30 (0.62 to 1.98) 0.000
Adverse Events Common Adverse Events:

FLIPUS related: N/A

Diclofenac sodium related:

Group I: dizziness (2%), vertigo (2%), and gastrointestinal symptoms (13%)

Group II: vertigo (2%), transaminase elevation (2%), and gastrointestinal symptoms (15%).

Serious Adverse Events: N/A
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions Focused low-intensity pulsed ultrasound (FLIPUS) is a safe and effective treatment modality that relieves pain, improves function and provides a higher quality of life (HRQoL) in patients with knee OA.

The small sample size, lack of long-term follow up, and safety profile of ultrasound therapy as studied makes long-term outcomes difficult to predict.  Although diclofenac sodium may have influenced positive results, it was administered to every patient and statistical significance confirmed the efficacy of FLIPUS over placebo treatment.  Since adverse events were minimal and the primary outcomes measured were thorough, this trial shows promising data which may provide the evidence needed to change future guidelines for therapy in osteoarthritis of the knee.

References

  1. What is osteoarthritis? Arthritis Foundation. http://www.arthritis.org/about-arthritis/types/osteoarthritis/what-is-osteoarthritis.php. Accessed November 8, 2016.
  2. Rutjes AWS, Nüesch E, Sterchi R, Jüni P. Therapeutic ultrasound for osteoarthritis of the knee or hip. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD003132. DOI: 10.1002/14651858.CD003132.pub2.
  3. Summary of Treatment Recommendations. Treatment of Osteoarthritis (OA) of the Knee (Non-Arthroplasty) Evidence Based Guideline 2nd Edition. Accessed Nov. 7, 2016. http://www.aaos.org/research/guidelines/TreatmentofOsteoarthritisoftheKneeGuideline.pdf.
  4. Jia L, Wang Y, Chen J, Chen W. Efficacy of focused low-intensity pulsed ultrasound therapy for the management of knee osteoarthritis: a randomized, double blind, placebo-controlled trial. Sci Rep. 2016; 6:35453.
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