The purpose of this study was to evaluate the
expression of acid-sensing ion channels (ASICs) in the capsule and synovial
fluid of patients with frozen shoulder. Capsular tissue and synovial
fluid were obtained from 18 patients with idiopathic frozen shoulder
(FS group) and 18 patients with instability of the shoulder (control
group). The expressions of ASIC1, ASIC2, and ASIC3 in the capsule
were determined using the reverse transcriptase-polymerase chain
reaction, immunoblot analysis, and immunohistochemistry (IHC). The
concentrations in synovial fluid were evaluated using an enzyme-linked
immunosorbent assay. The mRNA expression of ASIC1, ASIC2 and ASIC3 in the capsule
were significantly increased in the FS group compared with the control
group. The protein levels of these three ASICs were also increased.
The increased expressions were confirmed by IHC. Of the ASICs, ASIC3
showed the greatest increase in both mRNA and levels of expression
compared with the control group. The levels of ASIC1 and ASIC3 in
synovial fluid were significantly increased in the FS group. This study suggests that ASICs may play a role as mediators of
inflammatory pain and be involved in the pathogenesis of frozen
shoulder. Cite this article:
The LockDown device (previously called Surgilig)
is a braided polyester mesh which is mostly used to reconstruct the
dislocated acromioclavicular joint. More than 11 000 have been implanted
worldwide. Little is known about the tissue reaction to the device
nor to its wear products when implanted in an extra-articular site
in humans. This is of importance as an adverse immunological reaction
could result in osteolysis or damage to the local tissues, thereby affecting
the longevity of the implant. We analysed the histology of five LockDown implants retrieved
from five patients over the last seven years by one of the senior
authors. Routine analysis was carried out in all five cases and
immunohistochemistry in one. The LockDown device acts as a scaffold for connective tissue
which forms an investing fibrous pseudoligament. The immunological
response at the histological level seems favourable with a limited
histiocytic and giant cell response to micron-sized wear particles.
The connective tissue envelope around the implant is less organised
than a native ligament. Cite this article:
