DOS Kongressen 2014 ·
101
Frozen shoulder - appearance in the electron
microscope
Mads Okholm, Abigail Mackey, Klaus Qvortrup, Jens Jakobsen, Thomas Hansen,
Michael Krogsgaard
Ortopædkirurgisk Afd. M, Bispebjerg Hospital; Institute of Sports Medicine
Copenhagen, Bispebjerg Hospital; Core Facility for Integrated Microscopy,
University of Copenhagen; Ortopædkirurgisk Afd., Idrætskirurgisk Enhed M51,
Bispebjerg Hospital
Background:
Primary frozen shoulder (PFS) has been thoroughly described
clinically as well as histologically. To our knowledge, only a single study has ever
described the electron microscopic appearance of PFS capsule tissue, and no
study has ever compared the different phases of the disease.
Purpose / Aim of Study:
To evaluate and describe capsular tissue appearance
with the transmission electron microscope (TEM) in the 3 phases of PFS com-
pared to controls.
Materials and Methods:
Tissue samples from PFS capsules were taken during
arthroscopic capsular release. 8 samples were randomly selected from a larger
pool of tissue samples – these included two from each of the three phases and
two from controls (patients with subacromial impingement syndrome). Samples
were prepared for TEM, and two experienced observers evaluated the images
on a Philips CM 100 TEM. Tissue cellularity, collagen architecture and fibril ap-
pearance was described.
Findings / Results:
In general, the collagenous tissue was very dense in all
samples. Fibril diameter varied between 30 and 70 nm. In all phases, areas of
cross-sectioned fibrils with irregular, “hairy” edges were seen. In the phase 1
frozen shoulder samples, an abundance of large, irregularly shaped fibroblasts
with clearly dilated organelles (golgi apparatus, rough endoplasmic reticulum)
and intracellular lipid inclusions was noted. In phase 2 the cellular abundance
was still present, but without the same enlargement of cell size and organelles.
In phase 3 the cellularity was clearly reduced, and fibroblasts were small and
rounded with modest organelle size.
Conclusions:
In PFS, very active fibroblasts produce a densely packed collag-
enous tissue with many thick and irregular collagen fibrils. The morphology is
phase-related: The earlier the phase, the larger, more irregularly shaped and di-
lated fibroblasts.
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