scapula fracture classification system - Kreiskrankenhaus Mechernich

Classification of glenoid fractures 519
Table II Classification accuracy for patterns of simple fractures
of glenoid fossa
Surgeons and fracture categories Fracture classes
1 2 3
Class size 36% 19% 45%
Surgeon 1
1: Anterior rim or oblique 85%) 34% 29%
2: Posterior rim or oblique 0% 64%) 0%
3: Transverse or short oblique 15% 2% 71%)
Surgeon 2
1: Anterior rim or oblique 88%) 1% 1%
2: Posterior rim or oblique 1% 80%) 13%
3: Transverse or short oblique 11% 18% 87%)
Surgeon 3
1: Anterior rim or oblique 91%) 2% 1%
2: Posterior rim or oblique 0% 96%) 6%
3: Transverse or short oblique 9% 3% 93%)
Surgeon 4
1: Anterior rim or oblique 98%) 2% 9%
2: Posterior rim or oblique 0% 69%) 0%
3: Transverse or short oblique 2% 29% 91%)
Surgeon 5
1: Anterior rim or oblique 98%) 18% 1%
2: Posterior rim or oblique 0% 64%) 6%
3: Transverse or short oblique 1% 18% 93%)
Surgeon 6
1: Anterior rim or oblique 98%) 2% 19%
2: Posterior rim or oblique 1% 80%) 13%
3: Transverse or short oblique 1% 18% 68%)
Surgeon 7
1: Anterior rim or oblique 91%) 2% 6%
2: Posterior rim or oblique 8% 96%) 0%
3: Transverse or short oblique 1% 2% 93%)
Classification accuracies
Minimum 85% 64% 68%
Median 91% 80% 91%
Maximum 98% 96% 93%
) Percentages indicate surgeon classification accuracies (percentages
of correct classification).
mainly focused on scapula body and neck fractures.
Although they did not propose a classification system for
glenoid fractures, they documented involvement of the
glenoid in 17% of all scapula fractures. This incidence is
surprisingly low considering the fact that these authors
included fractures undergoing operative treatment.
According to the current treatment decision process, 24 the
fracture population of Armitage et al should have a bias
toward including proportionally more glenoid fractures. On
the other hand, Ada and Miller 1 reported glenoid fractures
in 10% of their series based on assessments using plain
radiographs. Such heterogeneity in the proportion of glenoid
fractures may be a reflection that the distribution of
fracture patterns is likely to differ between settings and, as
such, a comparison between scapula fracture studies
requires adequate classification and documentation.
The combination of a glenoid fracture and scapula body
fracture is frequent, so it is also important to have
a combined classification considering both the glenoid and
the rest of the scapula. This classification system should be
descriptive and comprehensive, as well as aid in the
decision-making process for individual therapy, especially
if minimally invasive approaches are intended. 12 To our
knowledge, the current scapula classification system is
most comprehensive as well as highly reliable and accurate.
Other existing scapula fracture classification systems lack
a more focused description of glenoid fractures. The
commonly used classification for glenoid fractures
according to Ideberg et al 18 and Goss 15 does not consider
the rest of the scapula; simple glenoid fracture lines
between anterior and posterior rim fractures (types Ia and
Ib) and transverse fractures (types II-V) are distinguished,
and type VI fractures represent multifragmentary fractures.
The classification of scapular fractures by Ada and Miller 1
distinguishes among 4 types of fractures including type III
glenoid fractures; however, further subclassifications of
glenoid fractures do not exist.
This evaluation is limited by its sample size, although it is
one of the largest ever used in such a project. There is often
a tradeoff between increasing the case collection and making
the evaluation feasible when busy clinicians are involved.
Results should be considered with caution when the number
of cases in any category is low, such as in the more detailed a,
b, and c category system. In addition, nothing can be said
about the reliability of coding multifragmentary glenoid
fossa fractures with central fracture-dislocation. Although
classification of F1 simple fossa fractures according to
anterior rim, posterior rim, or transverse patterns appears
reasonably reliable and accurate, location of these fractures
with regard to the 4 quadrants remains open for further
clarification and evaluation. The wide range of surgeons’
pair-wise k coefficients shows that different applications of
the definitions occurred among surgeons; thus, further
clarification and specification of the system are required.
Transverse or short oblique fractures typically separate
a process (ie, coracoid 3c) or involve the body (3a and 3b).
The 3a and 3b fractures are typically located near the
equator. In contrast, 1c and 2c rim fractures are much smaller
because they are located near the glenoid edge.
The classification process and evaluation sessions were
performed by experienced surgeons only, which may not
reflect the validity of the system in general practice. As
advocated by Audige et al, 4 a further study is required to
assess the reliability and accuracy of this classification
system when used by surgeons of varying education and
experience. Such evaluation would also consider the final
change made to the rim fracture categories. This study could
also be influenced by the preparation of the 3D volume
rendering datasets by only the main author. Furthermore, this
report is not intended to make recommendations regarding
any treatment modalities based on this classification
system at this early stage; rather, our intent is to provide