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Determining the contribution of active stiffness to reduced range of motion in frozen shoulder

PainSci » bibliography » Hollmann et al 2015
updated
Tags: etiology, counter-intuitive, neat, pro

Four articles on PainSci cite Hollmann 2015: 1. The Complete Guide to Trigger Points & Myofascial Pain2. Why Do Muscles Feel Stiff and Tight?3. Complete Guide to Frozen Shoulder4. The Role of “Spasm” in Frozen Shoulder

PainSci commentary on Hollmann 2015: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

Five capsular release surgery patients had their passive range of motion checked before and after being put under general anaesthesia. All five of them had “significantly more passive shoulder abduction” when they were knocked out … which would be impossible if their shoulder joint capsules were actually contractured or adhered or full of cement or had any physical limitation. The improvement in ROM ranged from a minimum of 44˚ all the way up to a 110˚ boost (all the way back to normal). The researchers reasonably concluded:

Passive range of motion loss in frozen shoulder is not be fully explained by a true capsular contracture alone. Passive ROM loss in FS is not be fully explained by a true capsular contracture alone. Passive shoulder abduction ROM assessed in awake patients with FS does not accurately reflect the true available ROM of the affected shoulder. It appears that active stiffness or muscle guarding is a major contributing factor to reduced ROM in patients with FS.

If I was the surgeon, I would have found it ethically hard to justify operating on these shoulders after seeing that.

It’s really a shame it was such a small study. We really need someone to do the same thing with five times as many patients.

~ Paul Ingraham

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

BACKGROUND: Frozen shoulder (FS) is a common cause of severe and prolonged disability and is characterized by the spontaneous onset of pain with progressive movement restriction of the shoulder joint. Although FS is frequently described as a self-limiting condition with gradual spontaneous recovery of function, the condition typically has a very protracted time course with symptoms lasting on average 30 months. In addition, about half of patients who suffer FS have long term continuing pain or restriction of movement. To date, the aetiology of FS is poorly understood. Varying patterns of fibrosis and contracture of ligamentous structures around the shoulder, as well as possible concurrent inflammatory processes have been reported in the literature. Despite extensive research in this area, it remains unclear to what extend a true contracture of the shoulder capsule is responsible for the significant loss of range of motion commonly experienced by patients with the condition.

PURPOSE: The aim of this study was to establish whether active stiffness, such as muscle guarding/splinting contributes to loss of range of motion (ROM) in patients with FS.

METHODS: Patients with a diagnosis of FS who had elected to undergo capsular release surgery were identified by an orthopaedic surgeon. Patients were eligible to participate if they experienced significant >40%) loss of active and passive ROM in at least two planes of shoulder movement compared to their healthy side. We examined passive shoulder abduction ROM in a total of five patients with FS. Passive abduction ROM was measured using digital photography on the day of the scheduled surgery immediately before entering the operating theatre and repeated in the operating theatre after general anaesthesia (GA) had been administered and prior to the surgical procedure.

RESULTS: All patients had significantly more passive shoulder abduction ROM under general anaesthesia compared to ROM measured while awake. The subject with the smallest difference in these two measures achieved an increase of 44° under general anaesthesia (94° awake vs 138° under GA); the subject with the largest demonstrated a 110° increase under general anaesthesia (55° awake vs 165° under GA).

CONCLUSION: This study demonstrated a variable but significant increase in passive ROM under GA in all patients, indicating that passive ROM loss in FS is not be fully explained by a true capsular contracture alone. Passive shoulder abduction ROM assessed in awake patients with FS does not accurately reflect the true available ROM of the affected shoulder. It appears that active stiffness or muscle guarding is a major contributing factor to reduced ROM in patients with FS.

IMPLICATIONS: Most conservative and surgical treatments for FS aim to increase shoulder ROM by stretching or releasing the shoulder capsule. This study demonstrates that at least a subset of patients with a clinical diagnosis of FS do not have significant capsular restriction. Being able to identify these patients is important to be able to implement an appropriate care pathway as alternative treatments addressing pain and active stiffness need to be considered.

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