Understanding shoulder pseudoparalysis. Part I: Definition to diagnosis

Key points

• Definitions of shoulder pseudoparalysis vary; the most widely used has been active forward elevation (AFE) below 90° with preserved passive range of motion in a massive rotator cuff tear without neurological impairment.
• The authors recommend grading loss of force couple balance separately for AFE, active external rotation (AER) and active internal rotation (AIR), and distinguishing pseudoparesis from pseudoparalysis.
• Pain must be excluded as the cause of lost active function, for example with a local anaesthetic injection.
• Loss of three out of five muscle–tendon units (upper and lower subscapularis counted separately) is predictive of pseudoparalysis; the lower subscapularis and the teres minor appear to be key players.
• True paresis or paralysis (C5 root, axillary or suprascapular nerve lesions) must be excluded before the diagnosis is made.

Overview

This EFORT Open Reviews article (Part I of two) clarifies the definition of shoulder pseudoparesis and pseudoparalysis in massive rotator cuff tears and describes their biomechanics, clinical examination and imaging. Its main message is that AFE, AER and AIR should be assessed independently and graded as pseudoparesis or pseudoparalysis, because these syndromes have different implications for treatment, which is covered in Part II.

Definitions and grading

The authors distinguish AFE pseudoparesis (under 90° of active elevation with full passive elevation, no anterior–superior escape, pain eliminated by local anaesthetic) from AFE pseudoparalysis (0° of active elevation with full passive elevation, usually with anterior–superior escape). AER is tested in 20° of abduction: in pseudoparesis active external rotation reaches neutral and full passive rotation lags back to neutral, while in pseudoparalysis there is no active external rotation and the arm lags back to −40°. AIR is graded with a modified belly-press test: wrist flexion of 30°–60° to keep the hand on the abdomen indicates pseudoparesis, and 90° indicates pseudoparalysis. Combined loss of elevation and external rotation (CLEER) is split into grade 1 (with AER pseudoparesis) and grade 2 (with AER pseudoparalysis).

Biomechanics and the shoulder equator concept

Shoulder function depends on force couple balance, with the rotator cuff centring the humeral head as a fulcrum against the pull of the deltoid. The lower subscapularis acts as an anterior inferior checkrein and the teres minor as a posterior inferior one. According to the shoulder equator concept, loss of all three anterior, all three superior or all three posterior muscle–tendon units is predictive of pseudoparalysis, so every effort should be made to prevent tear propagation into the subscapularis and the posterior cuff.

History, examination and imaging

The history covers duration, traumatic or chronic onset, pain and the effect of pain-eliminating injections. Examination includes C5 and axillary nerve function (Hertel deltoid extension lag test), the cervical spine (the Spurling test has a reported specificity of 93%), the external rotation lag and hornblower signs, and the belly-press, belly-off and lift-off tests (lift-off lag sign: sensitivity 95%, specificity 96%). True anterior–posterior and supraspinatus outlet radiographs are mandatory, with grading by the Hamada classification; CT and MRI assess retraction (Patte) and fatty infiltration (Goutallier, tangent sign).

Frequently asked questions

What is the difference between pseudoparesis and pseudoparalysis?

In pseudoparesis some active motion is preserved (for AFE, under 90°), whereas in pseudoparalysis active motion is absent (for AFE, 0°); in both, passive motion is preserved.

When is MRI mandatory?

In isolated chronic external rotation pseudoparesis or pseudoparalysis, to confirm the diagnosis and assess the infraspinatus and teres minor.

Why does fatty infiltration matter?

It is irreversible and progressive if left untreated, and tears with Goutallier stage 3 or 4 fatty degeneration have a poor prognosis for repair.

Source

Bauer S, Okamoto T, Babic SM, Coward JC, Coron CMPL, Blakeney WG. Understanding shoulder pseudoparalysis. Part I: Definition to diagnosis. EFORT Open Reviews 2022;7(3):214-226. DOI: 10.1530/EOR-21-0069. Open access (CC BY-NC licence). This page is a summary prepared by Medpresso from the original publication and is not a substitute for the full text or for medical advice.