Mill’s Test

Original Editor - Tyler Shultz, Matthias Verlinden

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Purpose

Mill's test aids in diagnosing Lateral Epicondylitis in the elbow, also known as “Tennis Elbow”.

Clinical presentation

Presenting equally in men and women, 1% to 3% of the population will experience lateral epicondylitis in their lifetime, usually between ages 35 and 50. Patients report pain at the lateral elbow that radiates down the forearm. Also, patients often complain of a weakened grip and difficulties lifting objects. On physical examination, patients typically have point tenderness medial and distal to the lateral epicondyle.

Condition	Patient age	Mechanism of injury	Symptoms aggravated by	Observation	Tenderness with palpation
Lateral epicondylitis	35-55	Gradual overuse	Activities involving wrist extension/grasping	Possible swelling (over the lateral elbow)	Lateral elbow (over extensor carpi radialis brevis)

Pathology

The histological aspects of the injury to the Extensor carpi radialis brevis (ECRB) origin appears to be multifaceted, involving hypovascular zones, eccentric & concentric tendon stresses, and a microscopic degenerative response.
In most cases, the lesion involves the specialized junctional tissue (intercellular adhesion molecules) at the origin of the common extensor muscle at the lateral humeral epicondyle, specifically the tendinous origin of the Extensor Carpi Radialis Brevis (ECRB), and in 35% of the cases, the origin of the Extensor Carpi Radialis Longus (ECRL) will also be overstrained. The lesion is characterized by microscopic tears, which may be superficial or deep and situated at the tendinous origin of ECRB into the periosteum of the lateral humeral epicondyle. Micro avulsion fractures may be seen as well as lymphocyte infiltration, calcification, scar tissue, and fibrinoid degeneration may be evident in some cases; repair is by immature fibroblasts.

Technique

The patient is seated, and the clinician palpates the patient’s lateral epicondyle with one hand while pronating the patient’s forearm, fully flexing the wrist, the elbow extended. A production of pain in the area of the insertion at the lateral epicondyle indicates a positive test.

Evidence

Sensitivity (%)	Specificity (%)	Positive Likelihood	Negative Likelihood
53	100	~ (infinity)	0.47

Other Techniques to Diagnose Lateral Epicondylitis

1. Maudsley’s test - Resisted third digit extension
2. Cozen’s test - Resisted wrist extension with radial deviation and full pronation
3. Chair lift test - Lifting the back of a chair with a three-finger pinch (thumb, index long fingers) and the elbow fully extended.

Key Research

A study (By Tuomo Pienimäki et al. 2002) found that pain thresholds at the lateral epicondyles are strongly associated with pain on palpation and a positive Mills test, providing evidence.

Wadsworth found that a forceful Mills movement under general anaesthesia produces an audible snap and provides good results, although no scientific reason is given. Hereby giving evidence for the effectiveness of the movement itself.

The Mills test is a very straightforward test that is described in most of the physical therapy manuals. Knowing that expert opinion is only level 5 evidence, consensus about diagnostic effectiveness by a range of experts can be used to make weak recommendations where there is a lack of higher-quality evidence.

More research is required.

Resources

The Mills test is named after the clinical findings by G Percival Mills, F.R.C.S who published his findings in The British Medical Journal (Jan 7th 1928) and updated this on July 31. 1937.