Hong Kong Med J 2014;20:145–51 | Number 2, April 2014 | Epub 28 Feb 2014
DOI: 10.12809/hkmj134110
© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
REVIEW ARTICLE
Lateral epicondylalgia: midlife crisis of a
tendon
James KH Luk, FHKCP, FHKAM (Medicine)1;
Raymond CC Tsang, MScHC (PT), PDPT2; HB Leung, FHKCOS,
FHKAM (Orthopaedic Surgery)3
1 Department of Medicine
and Geriatrics, Fung Yiu King Hospital, 9 Sandy Bay Road,
Pokfulam, Hong Kong
2 Physiotherapy Department,
MacLehose Medical Rehabilitation Centre, 7 Sha Wan Drive,
Pokfulam, Hong Kong
3 Department of
Orthopaedics and Traumatology, Queen Mary Hospital, 102 Pokfulam
Road, Pokfulam, Hong Kong
Corresponding author: Dr James KH Luk (lukkh@ha.org.hk)
Abstract
The pathogenesis and management of
lateral epicondylalgia, or tennis elbow, a common ailment
affecting middle-aged subjects of both genders continue to
provoke controversy. Currently it is thought to be due to local
tendon pathology, pain system changes, and motor system
impairment. Its diagnosis is usually clinical, based on a
classical history, as well as symptoms and signs. In selected
cases, additional imaging (X-rays, ultrasound, and magnetic
resonance imaging) can help to confirm the diagnosis. Different
treatment modalities have been described, including the use of
orthotics, non-steroidal anti-inflammatory drugs, steroid
injections, topical glyceryl trinitrate, exercise therapy,
manual therapy, ultrasound therapy, laser therapy,
extracorporeal shockwave therapy, acupuncture, taping,
platelet-rich plasma injections, hyaluronan gel injections,
botulinum toxin injections, and surgery. Nevertheless, evidence
to select the best treatment is lacking and the choice of
therapy depends on the experience of the management team,
availability of the equipment and expertise, and patient
response. This article provides a snapshot of current medical
practice for lateral epicondylalgia management.
Introduction
Tennis elbow is a diagnosis often heard in
the community and usually associated with an uncomplicated
clinical course. Surprisingly though, this minor self-limiting
ailment is linked to much controversy with respect to
nomenclature, pathophysiology, and management.
The term ‘tennis elbow’ was first used by
Rungue in 1873.1 It also
appeared in an 1883 paper by Major called ‘Lawn-tennis elbow’.2 The name tennis elbow is itself a misnomer as
it appears to be at least as common in non-tennis players.3 In the literature there are many names used to
describe the condition, including lateral epicondylalgia (LE),
lateral epicondylitis, lateral epicondylosis, shooter’s elbow,
archer’s elbow, and simply lateral elbow pain. In the remainder of
this article, the name ‘lateral epicondylalgia’ will be used. By
definition, LE is a degenerative tendinopathy characterised by
pain at the lateral epicondyle, aggravated by resisted muscle
contraction of the extensor carpi radialis brevis (ECRB).4 Studies in western countries usually report an
annual incidence of 4 to 7 per 1000 inhabitants, and at any given
time it is said to affect 1 to 3% of individuals in the general
population.5 Men and women
seem to be equally predisposed to and the age of onset is usually
between 35 and 55 years. A literature search yielded no
epidemiological data pertaining to Hong Kong, China, or other
Asian countries.
The typical duration of symptoms is between
6 and 24 months; up to 90% of sufferers report recovery within 1
year. However, 5 to 10% patients develop chronic symptoms and
eventually undergo invasive treatment such as surgery.
The injury is usually attributed to
eccentric contractions of the ECRB during backhand tennis swings,
which leads to repetitive microtrauma resulting in tears at its
origin.6 Others suggest
that direct trauma to the lateral aspect of the elbow,
hypovascularity, and fluoroquinolone antibiotics may also be
involved.7 8
It is common to believe that tennis players
are those most commonly affected by this condition. However, any
behaviour or activity associated with overuse of underused and
atrophied tendons can lead to LE.9
Indeed, many LE patients are not tennis players but subjects who
have been sedentary for years, and then suddenly begin exercising
(gardening, decorating a room, caring and lifting a baby, carrying
heavy luggage).
Pathophysiological model of lateral
epicondylalgia
Three interactive components seem to play a
part in its pathophysiology, namely: local tendon pathology, pain
system changes, and motor system impairment.10 11
The pathological changes in the tendon consist of
angiofibroblastic hyperplasia with an increase in cell number and
ground substance, vascular hyperplasia or neovascularisation,
increased concentrations of neurochemicals, as well as
disorganised and immature collagen formation. Ultrasonography
(USG) has demonstrated different tendon pathology, including
tendon thickening or thinning, focal areas of hypoechogenicity,
tendon tears, calcification, and even bony irregularity.12 Doppler USG in LE patients has also
demonstrated neovascularisation. The current view is that it is
not an inflammation and hence the old term epicondylitis is a
misnomer.13 Clinically,
inflammation is only present during the very early stage of the
disease and is very mild. On the contrary, there is a consistent
absence of inflammatory cells, suggesting that the process is not
an inflammatory process.
Change in pain perception (or the pain
system) may also contribute to the pathophysiology of LE. It has
been shown that substance P, a potent pain modulator, is located
at the ECRB tendon.14
Moreover, LE is itself associated with hyperalgesia and increased
response to noxious stimuli. Indeed, hyperalgesia can occur
bilaterally and not be confined to the affected side.15 Furthermore, spread of reduced pain threshold
beyond the LE site has been reported, especially over the cervical
spine. Previous studies have actually reported a high prevalence
of neck pain in patients with this condition.16
Motor system impairment consists of
diminished strength, with morphological changes in muscle and
altered motor control.17
It has been reported that both maximum hand grip and pain-free
grip are decreased, with the latter being considered more
sensitive to assess LE and thence recommended as a clinical
outcome measure. Patients with LE may have unilateral or bilateral
handgrip weakness. Specific muscle strength deficits, including
weakness in the wrist, hand, and shoulder have been demonstrated.
At the histological level, moth-eaten fibres, fibre necrosis,
signs of muscle fibre regeneration, and an increased proportion of
fast muscle fibre types are found in the ECRB.18
Understanding the pathophysiology of LE may
enable better targeting of treatment. The three model components
mentioned above probably operate differently in different
patients. Some patients with LE may have more pain system
disturbance, while others may have more local tendon pathology.
Clinicians should identify the relative involvement of local
pathology, pain, and motor system dysfunction in each patient with
LE. This may enable treatment strategies to be targeted better.
Clinical presentation, physical examination,
and investigation
The classical description is pain at the
lateral aspect of the elbow that often radiates down the forearm.
The patient may recall a specific injury, but often the pain is
gradual and of insidious onset. Weakness in grip or difficulty in
carrying items in the hand is common and affects quality of life
to a certain extent, depending on the severity of symptoms.
Physical examination should not be
restricted to the affected elbow. Clinicians should begin with
cervical spine, followed by entire upper limb, and careful
examination of the shoulder. In the elbow, there will be
tenderness at the lateral epicondyle, slightly distal to the
extensor mass. The specific test includes the Thomson manoeuvre,
in which pain is elicited by resisted wrist extension with the
elbow in full extension and the forearm in pronation.19 Several other provocative tests aid in the
diagnosis of LE, including the Chair test, the Bowden test,
Cozen’s test, and Mill’s test.20
These tests cause pain over the lateral epicondyle by putting the
ECRB in either eccentric contraction or passive tensioning. One
should beware of radial nerve entrapment which affects 5% of LE
patients, in which case pain may occur during resisted supination
when the nerve is trapped within the supinator muscle. The middle
finger extension test, resisted supination of the forearm, local
anaesthetic radial tunnel block, the Rule-of-Nine test, and nerve
conduction studies have all been described to help in the
diagnosis of radial tunnel syndrome.21
22 23 24
However, diagnosis of radial nerve entrapment may be difficult
when associated with LE. The elbow joint should also be checked
for stability, range of movement, signs of arthritis, and joint
effusion. Hand grip strength on the two sides has to be compared
and the readings documented. The elbow is usually X-rayed to rule
out other conditions. In about 25% of the patients, calcification
is present in the soft tissues around the lateral epicondyle.25 If USG is available, it can detect tendon
pathology, while Doppler USG may be able to demonstrate
neovascularisation. Further investigations, such as magnetic
resonance imaging, are usually unnecessary, unless there is
serious concern about other articular pathology.26
Treatment and outcome measurement
To date, a standardised, universally
accepted programme for LE treatment has not been established. Nor
is there a consensus as to what outcomes to measure, which makes
comparison of different treatment modalities difficult, if not
impossible. Common outcomes evaluated in the literature include
pain gauged by a visual analogue scale, hand grip strength, and
pain-free grip strength. One validated outcome evaluation tool is
the Patient-rated Forearm Evaluation Questionnaire, which has been
translated into a Hong Kong Chinese version.27 This questionnaire has been updated by the
originator and is called the Patient-rated Tennis Elbow
Evaluation.28 Since no
treatment protocol has been scientifically shown to be superior to
others, more than 40 different therapeutic options have been
offered to LE patients. To a large extent therefore, the choice
depends on experience, expertise, and equipment at any given
clinic or centre. Although treatment plans for LE vary in
different centres, patient education is usually one of the
important core elements.
Evidence about different treatment options
Non-steroidal anti-inflammatory drugs
Non-steroidal anti-inflammatory drugs
(NSAIDs) can reduce pain but do not improve long-term outcome, and
certainly they have their well-known side-effects, including
gastro-intestinal bleeding and impairment of renal function. There
is a theoretical risk of impaired tendon healing, as inflammation
is important for granulation tissue, collagen growth, and tendon
repair. Topical NSAIDs have been claimed to be beneficial for pain
relief in some small studies lasting up to 4 weeks.29 As mentioned in a recent Cochrane review,
evidence about the benefits of oral NSAIDs has been conflicting
and no direct comparisons between oral and topical NSAIDs are
available.30 Although
there is evidence that NSAIDs are more effective than placebo for
pain control, it is insufficient to support their routine use in
LE.
Corticosteroid injection
Corticosteroid injection is an effective
short-term means of achieving pain relief. However, their use for
the treatment of LE has been increasingly discouraged, partly
because no long-term benefit accrues, and partly due to high
recurrence rates. It is reported that 72% of patients treated with
steroid injections experience a recurrence within 12 months,
compared with 9% in those treated with a wait-and-see strategy.31 One recent study also
demonstrated a recurrence rate as high as 34.7% in a steroid
injection group.32 Another
newly published randomised controlled trial shows that steroid
injections result in lower rates of complete recovery compared to
placebo and a greater 1-year recurrence rate.33 Theoretically, such injections can impair
tendon healing, as inflammation is important for granulation
tissue formation, collagen growth, and tendon repair.34 Hence, the use of corticosteroid injections
for LE is a poor choice and should be avoided as far as possible
even as initial treatment.
Topical glyceryl trinitrate
Interestingly, glyceryl trinitrate (GTN)
can act as an agent to stimulate tendon healing. It is usually
given as a GTN patch, stuck directly over the site of the LE
(presumably for its psychological effect). Its side-effects
include headache, dizziness, and skin irritation. In 2003, Paoloni
et al35 reported a 21%
greater effect in LE when GTN (1.25 mg/24 hours) was combined with
exercise than with exercise alone. In 2009, the same investigators
also reported a significant decrease in LE pain after 8 weeks of
topical GTN (0.72 mg/24 hours).36
In 2011, McCallum et al37
followed up 58 patients treated for 6 months with topical GTN or
placebo combined with a rehabilitation programme, but 5 years
after discontinuation of therapy there was no difference in terms
of pain and hand grip strength. These findings suggest that
topical GTN did not offer additional long-term benefit.
Exercise therapy
Exercise is believed to stimulate tendon
remodelling and produce muscular adaptive responses. Various
resistance exercises have been prescribed to such patients,
including isometric, isokinetic, and isotonic concentric or
eccentric exercises. A recent systematic review38 including 10 studies of moderate quality and
two studies of high quality supported the use of isotonic
eccentric exercise for LE with moderate evidence of efficacy. It
suggested that an eccentric exercise programme performed as three
sets of 10 to 15 repetitions daily for about 6 to 12 weeks had the
best supporting evidence as a means of reducing pain, improving
function and pain-free grip strength, though optimal dosing was
yet to be determined.38 A
recent meta-analysis showed that stretching plus strengthening
exercises give better results than ultrasound plus friction
massage alone.39
Manual therapy
Deep transverse friction massage (DTFM)
relies on the theory of analgesia mediated via nonopioid
descending pain inhibitory mechanisms. According to the Cochrane
Library review, DTFM combined with other physiotherapy modalities
was no better than physiotherapy alone for pain control,
improvement of grip strength, and functionality.40
There are numerous manual therapy or
manipulation techniques, variously named as Mills, Cyriax,
Kaltenborn, Mennell, Stoddard, Hartman, Maitland, and Mulligan.41 Their rationale,
indications, and how they are applied vary. A more recent
systematic review based on four randomised controlled trials of
moderate-to-high quality found that Mulligan’s manual mobilisation
with movement provides better outcomes, such as pain-free hand
grip strength over the short and long term when compared to
placebo or other treatments such as ultrasound with exercise.42
Taping
The use of taping in LE is equally
controversial and no firm conclusions can be drawn at this moment.
Vicenzino et al43 compared
diamond-shaped taping over placebo and found significant
improvement in the intervention group in terms of the pressure
pain threshold. However, other benefits were not demonstrated.
Ultrasound therapy
Recourse to ultrasound is commonly offered
to LE patients, especially in the initial phase as it is readily
available in most physiotherapy centres and is safe. Lundeberg et
al44 reported that
compared to placebo the pain of LE patients was better 3 months
after such treatment, but there was no difference in global
improvement. One study compared ultrasound to acupuncture and
found that both yielded improvements in all outcome measures, but
there was no difference between the groups.45 Due to the paucity of high-quality trials at
this time, it is difficult to draw any conclusion to support or
refute the use of ultrasound in LE.
Extracorporeal shockwave therapy
Derived from lithotripsy, extracorporeal
shockwave therapy (ESWT) has been applied in orthopaedic treatment
since 1987. The principle is to use shockwave technology to
dissolve calcified deposits in diseased tendons.46 Lasting analgesia in the treated region has
also been observed. Achilles, quadriceps, triceps, and
supraspinatus are common ‘head upwards’ tendinopathies treated
with ESWT. However, it is known that calcification is rare in
tendons that head downwards, such as those involved in LE. So why
and how ESWT works in LE is unclear. The most accepted theory is
that the microtrauma from repeated shockwaves to the affected area
creates neovascularisation into the area and promotes tissue
healing.47 Because
re-inflammation is being induced, patients should not take
anti-inflammatory medication, nor should they ice the area, but
simple analgesics (such as paracetamol) may be acceptable. To
date, the US Food and Drug Administration has only approved this
treatment for plantar fasciitis and LE.48
Haake et al49 performed a
placebo-controlled study entailing 3 weeks of ESWT versus placebo,
but could not demonstrate any difference in outcomes, but more
side-effects (reddening of skin and small haematomas) were
reported with active treatment. In Hong Kong, a randomised
controlled trial of 74 patients failed to demonstrate the
beneficial effects of ESWT compared to placebo,50 as did another double-blind randomised
controlled trial.51
Laser therapy
A recent systematic review and
meta-analysis showed that laser therapy with an optimal dose of
904-nm wavelength applied to the extensor tendon insertions at the
lateral elbow appears to provide short-term pain relief and reduce
disability in LE, both alone and in combination with exercise
therapy.52
Orthotics
Different commercially available ‘tennis
elbow’ orthotics are being sold in stores. Most are in the form of
tennis elbow braces made of neoprene material, and are not
expensive. Whether they are useful is still not known. Jensen et
al53 compared an
off-the-shelf orthotic with steroid injections and concluded that
both were similarly effective in early management. Wuori et al54 compared off-the-shelf orthotics with placebo
braces and could not demonstrate any difference. Garg et al55 reported that for patients with LE, a wrist
extension splint can allow a greater degree of pain relief than a
forearm strap brace. The message of the Cochrane Library is that
due to the limited number of trials, few outcome measures, and
limited long-term results, no definite conclusions on their
effectiveness can be drawn.56
Acupuncture
Acupuncture is a contemporary treatment
modality for any type of painful condition, and LE is of no
exception.57 Molsberger
and Hille58 found that
acupuncture could achieve pain relief for a longer period than
placebo. Another study by Fink et al59
found that reduction in pain compared to placebo only occurred
early after treatment but there was no difference after 2 months.
Thus, there appears to be some evidence to support the efficacy of
acupuncture over placebo, but the effect is not long-lasting.
Platelet-rich plasma injections
The use of platelet-rich plasma (PRP)
injections has created a plethora of hope for curing LE. The
patient’s own blood is drawn and centrifuged, and the buffy coat
layer rich in platelet is isolated and injected into the patient.
The PRP is rich in platelet-derived growth factors which are
chemoattractive for white blood cells and mesenchymal stem cells.
It also contains transforming growth factor–beta, which promotes
cell mitosis and increases type I collagen production in tendon
sheath fibroblasts. It also has vascular endothelial growth factor
that stimulates angiogenesis. These factors have been shown to be
important in tendon repair.60
One randomised trial compared PRP injections with corticosteroid
injections and reported superior cure rates and pain scores after
PRP treatment.61
Currently, a large-scale study to evaluate the effectiveness of
PRP is awaited, before definitive recommendations can be made for
routine use. Regrettably, PRP treatment is not cheap and its
cost-effectiveness is therefore an important consideration.
Hyaluronan gel injection and botulinum toxin
Hyaluronan gel injection is used in
conditions such as osteoarthritis. A recent randomised controlled
trial showed that for LE, it was superior to placebo injections.62 How it works is unclear
but could be linked to effects on tendon degeneration; tendon
being similar to cartilage, may derive benefit in LE akin to that
in osteoarthritis. By contrast, injection of botulinum toxin into
the extensor digitorum longus muscle of the third and fourth
fingers to paralyse the muscle can unload the extensor tendon and
help the patient recover from LE.63
Its disadvantage is that the patient cannot extend the third and
fourth fingers for many months, which is disabling. It may be
considered in patients with severe LE symptoms who do not want or
are not suitable for surgery.
Surgery
It is estimated that about 4 to 11%
patients ultimately undergo surgery.64
The usual indications include intractable symptoms, persistent
symptoms despite conservative management (typically for at least
12 months). Many surgical procedures have been reported, including
extensor release with intra-articular modifications, extensor
fasciotomy, V-Y slide of the common extensor tendon, denervation
of the lateral epicondyle, epicondylar resection with anconeus
muscle transfer, and the Garden procedure with lengthening of the
ECRB.65 66 Minimally invasive techniques are also
available. It is beyond the scope of this review to describe each
of these surgical procedures in detail. Regardless of the
technique, successful treatment usually relies on patient
selection, identification of pathology, and complete resection of
the ECRB tendinosis. To date, evidence in support of surgery in LE
is lacking, and the Cochrane Library has classified surgical
treatment as having insufficient evidence to support or refute its
use.67
Conclusion
Tennis elbow, or LE, is a common yet
challenging condition to treat. Various non-surgical modalities
have been described, the selection of which depends on experience
of the management team, availability of the equipment, available
expertise, and patient choice/response. In general, treatment can
begin with patient education, application of commonly available
treatments (physiotherapy, manual therapy, tennis elbow brace, as
well as oral or topical NSAIDs). Steroid injection is not
recommended as it lacks long-term benefit and is associated with a
high relapse rate. When usual treatments fail to resolve symptoms,
injection of PRP may be an option, but its efficacy and
cost-effectiveness are not yet established. Injection of
hyaluronate may also be tried before resorting to surgery. Surgery
is usually indicated for resistant patients not responsive to
non-surgical therapy. More research is needed to evaluate the best
treatment modalities and protocols for LE sufferers.
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