Orthopedics This Week | December 5, 2017 | Page 19

ORTHOPEDICS THIS WEEK
VOLUME 13, ISSUE 38 | DECEMBER 5, 2017
trols. Thirty-six surgeries were analyzed
and out of them 92% of the players were
able to return to the NFL and most did
so within approximately five months of
their surgery. However, although they
returned at their preoperative perfor-
mance level and played similarly to the
control group, ultimately the controls
had a longer NFL career (p < .001) and
played in more games per season (p =
.026) than players who underwent sur-
gery. In addition, there was a decrease
(p =.013) in games/season for defensive
backs following surgery.
Harris told OTW that “the cases and
controls in the study were matched
by position, age, years of experience
in NFL, and performance data prior
to the surgery date in order eliminate
confounding variables. This left the
forearm fracture as the only variable to
account for the shorter career and fewer
games.”
“This is likely secondary to the need for
high speed and high impact use of the
arms in tackling,” he added.
Harris said that this however doesn’t
mean that another treatment would
necessarily offer better results. Previous
studies have shown that surgical fixa-
tion of forearm fractures leads to faster
recovery and decreased games missed
for elite athletes.
Instead he believes that the biggest
takeaway from their results is that study
should guide sports medicine physi-
cians and front office personnel in their
management of these injuries. This will
help ensure a better understanding of
what to expect post-surgery, that while
the overall prognosis is excellent with
greater than 90% of players returning
to sport with no significant decrease in
performance, the athletes’ career length
and games per season still may be nega-
tively impacted by the surgery. — TR
19
Alpine Skiing Helmet
Testing Should Hit the
Slopes
B
efore the 2013/2014 World Cup
Season, the International Ski Fed-
eration increased helmet testing speed
from 5.4 to 6.8 m/s for alpine downhill,
super-G and giant slalom to better pro-
tect skiers from head injury, but a recent
study, “Reconstruction of head impacts
in FIS World Cup alpine skiing,” pub-
lished online on November 25, 2017 in
the British Journal of Sports Medicine sug-
gests that head impact velocities in real
head injury situations on snow are actu-
ally higher than the current helmet rule.
Sophie Elspeth Steenstrup, physiother-
apist, MSc Sports Physiotherapy and
Ph.D. student at the Oslo Sports Trauma
Research Center in Oslo, Norway, and
colleagues analyzed nine head impacts
from seven head injury videos from the
International Ski Federation (FIS) Inju-
ry Surveillance Systems that occurred
between the years of 2006 and 2015.
They used commercial video-based
motion analysis software to measure
head impact kinematics and used angle
measurement software to measure the
sagittal plane angular movement.
According to the data, in seven of nine
head impacts, the estimated normal to
slope pre-impact velocity was higher
than the current FIS helmet rule of 6.8
m/s (mean 8.1 (±SD 0.6) m/s, range
1.9±0.8 to 12.1±0.4 m/s). The nine head
impacts had a mean normal to slope
velocity change of 9.3±1.0 m/s, range
5.2±1.1 to 13.5±1.3 m/s. In addition,
a large change in sagittal plan angular
velocity during impact was also found.
Steenstrup told OTW, “The biggest chal-
lenge with the study was obtaining high-
quality videos with a sagittal view (a view
from the side) of the injury situations.
Wikimedia Commons and Jon Wick
Because we could only obtain seven vid-
eos of good quality with a sagittal view,
the sample size is limited in our study.”
She added, “In addition, at the time
of the head impact, there was some
snow spray and camera blurring. Cou-
pled with limited temporal resolution
(meaning we had limited frame rates of
60 and 60 Hz), it was not possible to
accurately measure the kinematics dur-
ing the short duration of the impact.”
“However, the image quality until the
last frame before impact allowed for
accurate visualisation of helmet refer-
ence points and estimation of head
velocity immediately before impact,
as verified by the estimates of vertical
acceleration during flight.”
At this time, Steenstrup said that their
results do not indicate a need to change
the helmet impact velocities in FIS
mandated helmet rules in alpine ski-
ing because of the lack of information
on the relationship between real world
head impacts onto snow and ice and
laboratory head impacts during helmet
testing procedures.
“The next logical step for further
research, therefore, is for the relation-
ship between real head impacts on
snow and laboratory testing on rigid
anvils to be investigated further, by per-
forming helmet testing outside on real
World Cup prepared snow and ice,” she
said. — TR
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