Laser Treatment for Tendinitis

LaserWorld Guest Editorial, Nr 5 - 2000.

Jan M. Bjordal, PT-MSc, Faculty of Medicine, University of Bergen, Norway Christian Couppe, PT, Copenhagen, Denmark

Tendinitis is a common disorder of the musculoskeletal system. Cardinal symptoms from the tendon are pain from increased tension like muscle contraction or stretching and pain on pressure. In an acute stage inflammation is the most common pathophysiological manifestation, while degeneration of the collagen structure is observed in subacute and chronic cases. However, the episodic nature of chronic tendinitis with increased pain after strenous use of the affected tendon, may indicate that inflammation also play a part at this stage. A succesful strategy of treatment should include reduction of inflammation and regeneration of collagen. In the laboratory several experiments have shown that laser treatment may have the potential to achieve both these goals. The findings of the laboratory also shows that these effects are highly dependent on dose.

1. A synthesis of dose from 4 laboratory trials on inflamed collagen producing cell cultures gives the following dose for optimal reduction of tendon tissue inflammation:
   Dose : 3 - 8 J/cm2
   Intensity : 5 - 21 mW/cm2
   
2. A synthesis from 10 laboratory trials investigating collagen proliferation gives the following optimal dose for stimulation of tendon regeneration :
   Dose : 0.2 - 4 J/cm2
   Intensity : 2 - 10 mW/ cm2
3. For the treatment of tendinitis an optimal suggested dosage at target location will be :
   Dose : 0.2 - 4 J/cm2
   Intensity : 2 - 10 mW/ cm2
   

Treatment should be applied daily for at least five days to reduce inflammation, and for at least 10 days to increase collagen production.

Determination of clinical dose
The clinical dose depends on several factors such as laser type, depth to target from skin surface, the type of tissue between skinsurface and target location and the volume of injured tissue.

Characteristics for common tendon disorders
The various tendon locations have different characteristics that affects determination of dose.

Tendon Depth to target tendon (mm)
Tendon thickness (mm)
Typical area of tendon defect (cm2)

Values for different conditions are as follows:
Plantar fasciitis
10.0 - 12.0
3.0 - 4.0
0.1 - 0.8
Achilles
1.5 - 3.0
4.5 - 6.0
0.5 - 2.0
Patellar
2.5 - 4.0
5.5 - 8.0
1.0 - 4.0
Epicondylitis
1.5 - 2.5
2.0 - 4.0
0.09 - 0.3
Rotatorcuff
5.0 - 10.0
5.5 - 8.0
0.5 - 1.5

Recommendations for optimal laser therapy for common tendon disorders:
Infrared lasers (GaAlAs 820/830 nm) are recommended when :
* Power density on skin does not exceed 30 mW/cm2, when treating superficial disorders
* Spot size should not be smaller than 0.5 cm2

It must be added that there are only two clinical trials showing effect on tendinitis (rotatorcuff) with these lasers and that the dose recommendations for other locations are extrapolations and have not yet been tested clinically.

Infrared pulse lasers (GaAs 904 nm) are recommended when :
* Power density on skin does not exceed 20 mW/cm2, when treating superficial disorders
* Spot size should not be smaller than 0.5 cm2

Clinical results from seven trials suggests that pulse lasers overcome the skin barrier with less need for variation of dose for the different tendon locations.

Red HeNe lasers (632 nm) are only recommended for superficially situated tendon disorders like epicondyitis and paratendonitis of the achilles or patellar tendon. Use of HeNe laser on rotatorcuff, deeply situated patellar tendinitis (jumpers' knee), plantar fascitis or carpal tunnel is not recommended, due to the poor penetration of visible red light.

Editors note: The master thesis in Physiotherapy Science of Jan Bjordal is called "Low Level Laser therapy in shoulder tendinitis/bursitis, epicondylalgia and ankle sprain. A critical review on clinical effects". Division of Physiotherapy Science, University of Bergen. 1997.

Part of this thesis can be found in Physical Therapy Reviews. 1998; 3: 121-132. "What may alter the conclusions of reviews?".