The biochemical hypothesis of tendinopathies is updated: new research suggests the involvement of substances produced locally:

EpicondylitisDanielson P. Reviving the ” biochemical ” hypothesis for tendinopathy: new findings suggest the involvement of locally produced signal substances. Br J Sports Med 2009; 43; 265-8.

At the end of the twentieth century, Kahn and his colleagues reiterated the hypothesis that intratendinous biochemical mediators could interfere with locoregional nociceptive receptors. Five years later, the demonstration of production of substances by the tenocytes re-launch this hypothesis.

The inflammatory theory potentially responsible for chronic tendinopathies has been ruled out on several arguments:

• the microdialysis study did not find an increase in the level of prostaglandins E2 compared to asymptomatic subjects;

• the histological study of the tissues did not find inflammatory cells and rather emphasized the degenerative character of the tissues.

One of the theories about the genesis of pain has been to incriminate the separation of collagen fibers often found in tendinoses. This hypothesis was, however, refuted by Kahn, who emphasized the fact that the excision of a potential collagen fibers in the autografts with the patellar tendon is not very painful. However, the mechanical theory of overloading or overuse remains the most advanced hypothesis, especially since the tendons most frequently affected are those subjected to high stresses (calcaneal tendon, patella).

This hypothesis, however, does not explain everything since some sedentary patients suffer from tendinosis.

In 2000, Kahn proposed a biochemical theory that there would be an increase in sensory neurological fibers in tendinopathies. Although no study has confirmed this hypothesis, one important fact has been advanced: there are sensitive afferents in the tendon and the neighboring tissues. This does not explain everything but makes it possible to envisage that these sensory afferents may be affected in their transmission either by other components of the nervous tissue or by substances produced within the tendon itself.

It would appear that afferent afferent fibers and sympathetic afferent fibers coexist within the same fascicles.

In tendinopathies, the source of catecholamines would be the tenocytes themselves, also containing enzymes for the synthesis of acetylcholine. These enzymes were not found in control tendons. In addition, they have been particularly prominent in patients with severe resistant tendinopathy.

It has been shown that acetylcholine, when applied to human skin, can cause pain.

Moreover, in the rat, carbachol, analog of acetylcholine, would stimulate the nociceptive receptors (experiment in vitro on the skin). This has not been confirmed in other experiments.

Glutamate receptors have recently been found in glutamate receptors in the tenocytes, and higher rates of glutamate have been found by microdialysis in chronic pain tendons compared to those present in healthy tendons.

Acetylcholine and substance P receptors were also detected in the vessel walls.

However, echo-doppler studies have shown an increase in local vascularization in tendinopathies, which may be due either to vasodilation of the local circulation or to the formation of neovessels.

Recently, Scott et al. have demonstrated a vascular endothelial growth factor in painful patellar tendons absent in healthy tendons, thus reinforcing the thesis of neovessels.

In animals, acetylcholine and norepinephrine induce the expression of collagen genes in hepatic myofibroblastic cells.In the tendinopathies, the cells would have resemblances to the myofibroblasts. In addition, prolonged stimulation of catecholamine receptors in rat fibroblasts induces proliferation of these cells. In addition, stimulation of acetylcholine receptors in pulmonary fibroblasts causes the accumulation of collagen.

In summary, studies of recent years have shown the existence of a production by the tenocytes of chemical signals usually located in neurons, reinforcing the biochemical thesis of a modification of the local production of substances responsible for waterfalls. events and source of pain.

Although new animal studies are needed, the possible therapeutic implications of such discoveries are immediately apparent: blocking neurotransmitters, modifying their local production. . .

As Claude Bernard said:  A fact in itself is nothing. It is worth only by the idea to which it is connected or the proof that it brings.  .

Long-term follow-up of arthroscopic treatment of epicondylitis:

Baker Jr, Baker III. Long-term follow-up of arthroscopic treatment of lateral epicondylitis. Am J Sports Med 2008; 36: 254-60.

In epicondylalgia, the lesion, due to overuse, is characterized by microdegradations of the extensor tendon carpi radialis brevis (ECRB); it is possibly clogged with repair tissue consisting of disorganized collagen, immature fibroblasts and vascular elements. There is currently no consensus regarding the best way to manage epicondylialgia.If most patients respond to conservative treatment, literature findings show that 25% use surgery. Several surgical techniques have been described with good results in the published series.

Goal of the study:

Remote evaluation of arthroscopic treatment of epicondylialgia.

Operating technique:

An internal approach path located 2 cm upstream of the internal epicondyle; an external first channel; debridement with a shaver of the injured tissues at the insertion of the ECRB and in the surroundings; disintegration of this tendon.

Descriptive classification of lesions:

• type 1: capsule of the intact radio-humeral joint, torn ECRB tendon;

• type 2: linear tears of the capsule;

• type 3: complete rupture of the capsule.

Material and method:

Retrospective study; followed by 30 patients at 130 months; average age of 43 at the time of surgery; assessment of three items: elbow pain (rest, daily life, activity), Nirschl scale, Mayo Clinic scale (12 functional items).

Results and discussion:

The average pain score was 0 at rest, 1 during activities (0-5), and 1.9 in case of restrictive activities.

All long-term patients remained well short-term.

On the Nirschl scale, 24 patients out of 30 (80%) reported having never had pain or very occasionally, while the other six had pain only in case of physically restrictive activities.

Results according to lesion classification: seven patients (23%) had type 1, 15 (50%) type 2 and eight (27%) type 3 lesions. No statistical differences were found between the different lesions groups in pain or functional performance.

None of the patients underwent surgery or infiltrations after arthroscopy; 29 patients (97%) said they were improved or very much improved, while only one (3%) had no change in their pain; 22 patients (73%) had retained their jobs (eight manual jobs, 14 office jobs), six had stopped for reasons other than their elbow problem, one had to change jobs.


The study shows that arthroscopy is a reliable technique. In addition, it allows a more rapid initiation of postoperative rehabilitation and a return to work earlier than traditional techniques.

Short-term efficacy of laser, cuff and ultrasound in the treatment of lateral epicondylitis:

Oken O, Kahraman Y, Ayhan Y. The short-term efficacy of laser, brace, and ultrasound treatment in lateral epicondylitis: a prospective randomized controlled trial. J Hand Ther 2008; 21: 63-8.

Goal of the study:

Compare the effectiveness of a low-frequency laser to the wearing of a bandage or ultrasound in the management of epicondylitis.

Material and method:

n = 58; randomized study.

Three groups:

• wearing a bandage all day for two weeks (n = 20);

• ultrasound group: continuous mode, frequency of 1 MHz, intensity of 1.5W / cm 2 , five minutes, five times a week for two weeks, plus the application of a warm pack (n = 18);

• Laser group: five sessions per week of ten minutes for two weeks, combined with the use of a local hot pack.

In all three groups, learning of muscle stretching and strengthening exercises then performed at home (ten sets, three times a day).

Assessment: clamping force (Jamar), pain intensity (VAS), overall assessment (six-level value scale).


Average age = 45.3 ± 8 years; mean duration of symptoms = 4.7 ± 5.1 months.

Overall improvement in the three groups but at six weeks, intensified pain in the bandage group while the results continue to improve in the other groups. The same improvement was observed in the clamping force.

Regarding the overall assessment: worsening in the bandage group, no change in the ultrasound group, improvement in the laser group.


All patients noted an improvement in their symptoms at two weeks. The bandage provided relief only when worn continuously.

Although the literature does not provide conclusive results, the study shows the effectiveness at six weeks of laser and ultrasound on pain in epicondylialgia. In addition, laser treatment improves clamping force.

Limitations of the study:

Reduced workforce in each group, lack of long-term follow-up, non-evaluation of results on daily activities. Moreover, the addition of exercises to treatment distorts the interpretation of the results.

The three times of bone scintigraphy in chronic epicondylitis:

Pienimäki T, Takalo R, Ahonen A. Three-phase bone scintigraphy in chronic epicondylitis. Arch Phys Med Rehabil 2008; 89: 2180-4.

Goal of the study:

To evaluate the usefulness of the three phases of bone scintigraphy as a complementary diagnostic method in a group of patients with chronic epicondylitis and to compare the results with the clinical examination data.

Material and method:

n = 59 patients with chronic epicondylitis who did not feel any relief despite various treatments tested: plaster immobilizations, oral treatments, application of local NSAIDs, rehabilitation treatments, corticosteroid infiltrations.

Collection of clinical data:

Interviewing, questionnaire pain evaluation (seven items), search for local pain points (palpation, mill maneuver), clamping force, isokinetic performance of the flexors, extensors, pronator and supinator of the wrist.

Inclusion Criteria:

• medial epicondylitis (seven): local painful point on palpation + positivity of two to three induced pain tests;

• lateral epicondylitis: local pain at palpation + positivity of at least one induced test.


Clichés at 30 seconds, six minutes and three hours postinjection.

Interpretation by two independent radionuclear physicians compared to the opposite side.


The increase in fixation was 33% in men and 17% in women, at the level of the pathological elbow compared to the opposite side.

Early (vascular) fixation seems to correlate with symptom duration and clamping force.

Fixation to late (bone) time seems to be related to work aptitude and muscle strength. No link was established with either manual or subjective pain assessment results.

Responses to physical tests as well as the number of infiltrations received previously do not modify the scintigraphy.


Bone hyperfixation can be either a local healing phenomenon or a hyperuse.

Vascular hyperfixation reflects chronic inflammation.

Limitations of the study:

The small size of the samples, the heterogeneity of the groups concerning the age of the symptoms (acute, subacute, chronic).

Absence of effectiveness of a forearm armband, muscle strengthening exercises in the treatment of tennis elbow: prospective randomized study

Luginbühl R, Brunner F, Schneeberger A. No effect of forearm band extensor, strengthening exercises for the treatment of tennis elbow: a prospective randomized study. Chir Organi Mov 2008; 91: 35-40.

There are various conservative treatments for tennis elbow.

Applying a non-elastic circular band around the forearm, by decreasing the contraction force of the wrist and finger extensors, would reduce tension on the tendon, facilitating its healing.

Goal of the study:

Determine the role of a forearm support and a muscle strengthening program in the treatment of tennis elbow.

Material and method:

Prospective study; n = 29; therapeutic protocol: local infiltration of an anesthetic-corticoid mixture and initiation of one of three therapeutic modalities: either wearing a diurnal bandage for three months (n = 9) or a muscle strengthening program for three months (n = 10) (isometric tightening exercises), or two (n = 10) after two weeks of exercises versus wrist extension resistance.

The age of symptoms was 10 ± 11 months.

Assessment (pre-therapeutic, six weeks, three months, one year): joint amplitudes, clamping force.


At six weeks, significant improvement in the three groups. This is lessened over time while maintaining a certain number of patients: 18 patients consider themselves to be improved, 11 say they are similar to the pretreatment phase, and even more aggravated.

In the bandage group, two patients discontinued treatment before the final duration, one feeling improved early, the other not having improved.

In the exercise group, six patients were compliant.

In the combined group, one patient prematurely stopped the protocol due to increased pain.

She was operated nine months later.

No difference could be noted between the three groups regarding self-appreciation, clamping force.

Better results were achieved in patients with 90% improvement after infiltration.


No positive influence was noted either in the wearing of the bandage or in the practice of muscle building exercises, although it was difficult to monitor the quality and intensity of these exercises.

Considering the subjective assessment of patients, regardless of the type of treatment, 63% feel better about their pre-therapeutic status. This result seems similar to the Smidt series, which reported 69% of satisfied patients after corticosteroid infiltration.

Practicing exercises while wearing the bandage ready for discussion because it would limit the maximum contraction of the extensors of the wrist and fingers.

Limitations of the study:

The small number of patients in each group, the absence of controls.


No benefit in wearing bandages or strengthening exercises could be demonstrated in the study.

General comments from the editors

Lateral epicondylitis is a chronic condition.

The daily practice shows that spontaneous evolution is generally favorable whatever the treatment applied. Thus, published studies would require a rigorous methodology to judge whether or not a diagnostic or therapeutic measure is effective. In the work of this press review, as in many others, one can regret the heterogeneity of the population and the pathologies studied, not allowing to give the results found all the implications desired.