MRI for Lateral Elbow Pain: Comparison of Affected and Unaffected Elbows

Enthesopathy of the origin of the extensor carpi radialis brevis (ECRB) is also
know as lateral elbow pain, lateral epicondylitis, lateral epicondylosis, or
tennis elbow. Lateral epicondylosis may be the most prevalent of many common
degenerative disorders of muscle and ligament insertions that occur in
middle-aged humans, and annual incidence in general population is approximately
1-3%. Lateral elbow pain is a benign and self-limiting condition. Symptoms will
usually recover over the course of approximately twelve to eighteen months. The
role of operative treatment is incompletely defined.
The pathological changes in the origin of the ECRB appear as edema, partial
thickening, and tendon defects (often labeled as partial or complete *tears*)
on Magnetic Resonance Imaging (MRI). In addition, edematous changes in the
anconeus muscle have been reported. Asymptomatic pathological changes on MRI
of the contralateral arm are common in patients with rotator cuff tendinopathy
and there is some evidence that the same may be true for lateral epicondylosis.
Studies have described similar changes on MRI of asymptomatic elbows as well.
For instance, Martin et al. reported changes on MRI in 3 of 16 individuals
(19%) without symptoms of lateral elbow pain. Two previous studies suggested
the presence of degenerative changes in 27% to 54% of asymptomatic elbows as
compared to 70% to 100% in symptomatic elbows.
Limitations of these studies include limited power (only 11 and 17
contralateral elbows imaged, with 6 MRI abnormalities in each study), technical
issues (lowfield or highfield MRI only), and inclusion of patients with
complaints of bilateral elbow pain. To the best of our knowledge, there have
been no adequately-powered prospective studies with the primary study objective
being a comparison of MRI findings between symptomatic and asymptomatic elbows
in unilateral epicondylosis . The purpose of the current study is to compare
MRI findings between affected and unaffected elbows in patients with clinically
diagnosed unilateral lateral elbow pain.

The purpose of the current study is to compare MRI findings between affected
and unaffected elbows in patients with clinically diagnosed unilateral lateral
elbow pain
Given the considerable number of degenerative changes in asymptomatic elbows
reported in previous investigations, it is unclear if such changes explain the
symptoms that patients experience. Furthermore, we believe that the finding of
a defect or *tear* tends to be overinterpreted and probably does not merit
specific treatment. The aim of this research study is to obtain objective data
about degenerative changes in the affected and unaffected elbow in patients
diagnosed with lateral elbow pain.

All patients that meet the eligibility criteria will be invited to our
outpatient clinic. An independent research fellow not involved with patients*
care will explain the study in detail and informed consent will be obtained. It
will be explained that participation is voluntary and that subjects can
withdraw at any time during the study. Withdrawal will not influence further
care and treatment.
C. Study Procedures
Upon consent, demographics (age, gender, and occupation) will be collected and
patients will be asked to complete two questionnaires: Questionnaire A (time
since onset of symptoms, previous treatment, limb dominance, and a VAS pain
scale) and Questionnaire B (the Disabilities of Arm Shoulder and Hand
questionnaire (DASH) [36]. In addition, grip strength of both arms will be
measured by the independent researcher as the average of three attempts using a
handgrip meter (Preston; Jackson, MI, Jamar [34,35], ) placed at the third
station with the arm at the side, the elbow at 90° flexion, and the forearm and
wrist in neutral position. Grip strength of the involved arm will be compared
with the opposite side, and the percentage of grip strength
(involved/noninvolved arm) will be calculated.

Subsequently, MRI scans (T1 and T2) will be made of both the affected as the
unaffected elbow. The MRI scans will be evaluated by an independent
radiologist for presence of edema, partial thickening, microtears, partial or
complete tears, avulsion of the common extensor tendon, or any other
abnormalities. In addition, the signal intensity of the common extensor tendon
will be graded as done in previous studies[16,20]: mild (thickened or thinned
tendon, with increased MRI signal), moderate (presence of partial tendon
tears), or severe (complete tendon tear or avulsion).

not applicable