Aims. The aim of this study is to provide a detailed description of cases combining bridging patch repair with
Dislocation of the acromioclavicular joint is
a relatively common injury and a number of surgical interventions
have been described for its treatment. Recently, a synthetic ligament
device has become available and been successfully used, however,
like other non-native solutions, a compromise must be reached when
choosing non-anatomical locations for their placement. This cadaveric
study aimed to assess the effect of different clavicular anchorage points
for the Lockdown device on the reduction of acromioclavicular joint
dislocations, and suggest an optimal location. We also assessed
whether further stability is provided using a coracoacromial ligament
transfer (a modified Neviaser technique). The acromioclavicular
joint was exposed on seven fresh-frozen cadaveric shoulders. The
joint was reconstructed using the Lockdown implant using four different
clavicular anchorage points and reduction was measured. The coracoacromial
ligament was then transferred to the lateral end of the clavicle,
and the joint re-assessed. If the Lockdown ligament was secured
at the level of the conoid tubercle, the acromioclavicular joint
could be reduced anatomically in all cases. If placed medial or
2 cm lateral, the joint was irreducible. If the Lockdown was placed
1 cm lateral to the conoid tubercle, the joint could be reduced
with difficulty in four cases. Correct placement of the Lockdown
device is crucial to allow anatomical joint reduction. Even when the
Lockdown was placed over the conoid tubercle, anterior clavicle
displacement remained but this could be controlled using a coracoacromial
ligament transfer. 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: