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Effects of hyperbaric oxygen therapy on recovery acceleration in Japanese professional or semi-professional rugby players with grade 2 medial collateral ligament injury of the knee: A comparative non-randomized study

Authors:

Abstract

Introduction: The effects of hyperbaric oxygen (HBO2) therapy on sprains, ligament injuries, and muscle strains have been reported in several animal studies. In a dog model of compartment syndrome and in a rat contused skeletal muscle injury model, the significant effects of HBO2 therapy on the reduction of edema and muscle necrosis have been reported. In basic research HBO2 therapy stimulated fibroblast activity to improve the healing process. Because of this it expected that HBO2 therapy might improve focal edema and pain in the acute phase and accelerate the healing of injured tissues in athletes with a medial collateral ligament (MCL) injury of the knee. This study aimed to examine the short-term effects of HBO2 application subjectively, and the long-term effects of HBO2 therapy in Japanese professional or semi-professional rugby players with grade 2 MCL injury of the knee. Methods: Thirty-two professional or semi-professional rugby players with grade 2 MCL injury of the knee were investigated. First, in the HBO2 group (n=16), HBO2 therapy was performed during the acute phase. Visual analog scales (VASs) immediately before and after HBO2 therapy on the same day were compared. Next, we retrospectively evaluated the time to return to play in the HBO2 (n=16) and non-HBO2 (n=16) groups. Results: VAS scores for pain while walking immediately before and after HBO2 therapy on the same day were 37.4 ± 20.1 (mean ± standard deviation) and 32.4 ± 21.8, respectively (p⟨0.001). The VAS scores for pain while jogging were 50.7 ± 25.6 and 43.9 ± 25.0, respectively (p⟨0.001). The time to return to play was 31.4 ± 12.2 days in the HBO2 group and 42.1 ± 15.8 days in the non-HBO2 group, indicating a significant difference between the groups (p⟨0.05). Conclusion: HBO2 therapy may reduce pain and accelerate the return to play in athletes with grade 2 MCL injury of the knee in this non-randomized study.
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UHM 2019, VOL. 46 NO. 5 HYPERBARIC OXYGENATION AFFECTS VASCULAR RELAXATION UHM 2019, VOL. 46 NO. 5 EFFECTS OF HBO2 ON GRADE 2 MCL INJURY
Copyright © 2019 Undersea & Hyperbaric Medical Society, Inc.
RESEARCH ARTICLE
Eects of hyperbaric oxygen therapy on recovery acceleration in Japanese
professional or semi-professional rugby players with grade 2 medial collateral
ligament injury of the knee: A comparative non-randomized study
Kazuyoshi Yagishita, MD 1,2, Mitsuhiro Enomoto, MD 1,2, Yuji Takazawa, MD 3,
Jun Fukuda, MD 4, Hideyuki Koga, MD 5
1 Hyperbaric Medical Center, Tokyo Medical and Dental University
2 Clinical Center for Sports Medicine and Sports Dentistry, Tokyo Medical and Dental University
3 Department of Orthopaedic Surgery, Juntendo University School of Medicine
4 Department of Health and Sports, Fujisawa Shounandai Hospital
5 Department of Orthopaedic Surgery, Tokyo Medical and Dental University
CORRESPONDING AUTHOR: Kazuyoshi Yagishita – yagishita.orth@tmd.ac.jp
____________________________________________________________________________________________________________________________________________________________________
______________________________________________________________________________________________________
KEYWORDS: hyperbaric oxygen therapy; medial collateral ligament; return to play; pain reduction; recovery acceleration
Introduction: The effects of hyperbaric oxygen (HBO2)
therapy on sprains, ligament injuries, and muscle strains
have been reported in several animal studies. In a dog model
of compartment syndrome and in a rat contused skeletal
muscle injury model, the significant effects of HBO2 therapy
on the reduction of edema and muscle necrosis have been
reported. In basic research HBO2 therapy stimulated fibroblast
activity to improve the healing process. Because of this it
expected that HBO2 therapy might improve focal edema
and pain in the acute phase and accelerate the healing of
injured tissues in athletes with a medial collateral ligament
(MCL) injury of the knee. This study aimed to examine the
short-term effects of HBO2 application subjectively, and the
long-term effects of HBO2 therapy in Japanese professional
or semi-professional rugby players with grade 2 MCL injury
of the knee.
Methods: Thirty-two professional or semi-professional
rugby players with grade 2 MCL injury of the knee were
ABSTRACT
investigated. First, in the HBO2 group (n=16), HBO2 therapy
was performed during the acute phase. Visual analog scales
(VASs) immediately before and after HBO2 therapy on the
same day were compared. Next, we retrospectively evaluated
the time to return to play in the HBO2 (n=16) and non-HBO2
(n=16) groups.
Results: VAS scores for pain while walking immediately
before and after HBO2 therapy on the same day were 37.4 ± 20.1
(mean ± standard deviation) and 32.4 ± 21.8, respectively
(p<0.001). The VAS scores for pain while jogging were
50.7 ± 25.6 and 43.9 ± 25.0, respectively (p<0.001). The
time to return to play was 31.4 ± 12.2 days in the HBO2 group
and 42.1 ± 15.8 days in the non-HBO2 group, indicating a
significant difference between the groups (p<0.05).
Conclusion: HBO2 therapy may reduce pain and accelerate
the return to play in athletes with grade 2 MCL injury of the
knee in this non-randomized study. z
____________________________________________________________________________________________________________________________________________________________________
INTRODUCTION
Aer sustaining injuries during sports, athletes are usually
required – and desire – to return to competition rapidly.
In particular, high-level athletes are required to return
to play as soon as possible. erefore, safe and eective,
multidisciplinary treatments should be established. Ath-
letes prefer such therapies, as they accelerate their return
to competition.
Injury to the medial collateral ligament (MCL) of the
knee is a frequently encountered sports injury. e inci-
dence rate of MCL injury during sports activity ranges
from 0.04 to 3.1 MCL injuries per 1,000 hours of athlete
exposures (AEs) [1-3]. Moreover, the incidence rate
during rugby competitions is relatively high [1].
As with other so-tissue injuries, MCL injury under-
goes four stages of healing. ese include: hemorrhage,
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UHM 2019, VOL. 46 NO. 5 EFFECTS OF HBO2 ON GRADE 2 MCL INJURY
Yagishita K, Enomoto M, Takazawa Y, et al.
inammation, repair, and remodeling [4,5]. e acute
inammatory phase is characterized by edema, pain, and
a limited range of motion, which prevents aected in-
dividuals from returning to sports activities. A rapid
reduction of pain and tissue edema at the injured site
during the acute phase would accelerate the healing
potential and reduce the time to return to previous
levels of competition.
Hyperbaric oxygen (HBO2) therapy has been noted
as eective for wound healing and so tissue injury,
including crush injury and compartment syndrome [6-10].
e eects of HBO2 therapy on so tissue injuries during
sports activities, including sprains, ligament injuries,
contusions, and muscle strains, have been reported by
several basic and clinical studies [11].
In the acute phase, HBO2 therapy improves hypoxic
tissue microcirculation following a reduction in edema.
In a dog model of compartment syndrome, signicant
eects of HBO2 therapy on the reduction of edema and
muscle necrosis have been reported [11-13] In animal
research HBO2 therapy stimulated broblast activity to
improve the healing process [14], and promoted liga-
ment healing and maximum failure load aer injury in
the remodeling phase in a rat model [15-17]. Clinical-
ly, HBO2 therapy may provide short-term eects such
as reducing edema and pain in athletes with acute an-
kle sprain, as shown in a pilot study [29]. James, et al.
rst documented the quantitative eectiveness of HBO2
therapy in sports injuries. In this preliminary report the
actual days of untness compared to the estimated days
assessed by the club physiotherapist resulted in a 70%
decrease in injury time for returning to football activities
in Scotland [36].
We reasoned therefore that HBO2 therapy might help
improve focal edema and pain in the acute phase
and accelerate the healing of injured tissues in athletes
with MCL injury of the knee. However, Barata, et al.
documented a literature review that demonstrates that
although results have proven to be promising in terms
of using HBO2 as a treatment modality in sports-related
injuries, these studies have been limited due to the small
sample size, lack of blinding, and issues with ran-
domization [22]. As there have been few quantitative
evaluations of HBO2 therapy for MCL injury, HBO2
eectiveness has not been claried in detail.
is comparative non-randomized study aimed to
evaluate the clinical ecacy of HBO2 therapy in athletes
with grade 2 MCL injury of the knees. e subjects in this
study included professional or semi-professional rugby
players. e primary outcome was dened as the short-
term eects of HBO2 therapy in the HBO2 group in the
acute phase of injury in terms of subjective VAS evalu-
ation compared immediately before and aer HBO2
therapy. e secondary outcome was dened as the
long-term eects of HBO2 in terms of the time to return
to play compared between the HBO2 and non-HBO2
groups.
MATERIALS AND METHODS
is study was approved by the institutional review
board of Tokyo Medical and Dental University in 2007.
Each subject in the HBO2 group provided written in-
formed consent before participating in the study and
starting HBO2 therapy. is study was undertaken in
full accordance with the ethical standards in the
Declaration of Helsinki.
Subjects
A total of 32 professional or semi-professional rugby
players with grade 2 MCL knee injury that occurred
during sports activity and during the rugby season that
extended from June to January were investigated in
this study. All subjects belonged to the “Top League”
Japanese rugby league, which is the top category of the
Japanese Rugby Federation.
e diagnosis of grade 2 MCL injury was made via
clinical examination by the authors, who were the
team medical doctors. eir specialty was orthopedics
and sports medicine, and they possessed a keen ability to
diagnose injuries accurately.
e grade of MCL injury was judged by manual
examination as follows, and any right-le asymmetry
was considered a positive nding:
A) grade 1: negative instability in the manual valgus
stress test at full extension and at 30 degrees of knee
exion, and positive tenderness at the injured MCL
site;
B) grade 2: negative instability in the manual valgus
stress test at full extension, and positive instability
in this test at 30 degrees of exion; and
C) grade 3: positive instability in the manual valgus
stress test at full extension and at 30 degrees of exion
(Table 1).
Exclusion criteria included a past history of MCL injury
and/or other knee joint injuries including anterior cruciate
ligament injury or meniscus injury.
From 2007 to 2011 all the patients with grade 2 MCL
injury during the acute phase within six days of injury
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Yagishita K, Enomoto M, Takazawa Y, et al.
in four teams were referred to our hospital. All the cases
were included in this study. All the cases were enrolled,
consented, and underwent treatment with HBO2 therapy
(HBO2 group, n=16). From 2001 to 2006, patients with
grade 2 MCL injury were not administered HBO2 therapy
and were determined as the non-HBO2 group (n=16).
e data in the non-HBO2 group were collected from
their team doctors or their trainers.
Hyperbaric oxygen therapy protocol
e HBO2 chamber in our hospital is a multiplace unit
capable of holding 16 patients (NHC-412-A, Nakamura
Tekko-Sho Corp., Tokyo, Japan). In this series HBO2 ther-
apy was performed using 2.8 atmospheres absolute (ATA)
(283.6 kPa) for 60 minutes. In the HBO2 group (n=16),
HBO2 application started as soon as possible, including
the same day of injury (Day 0). Each patient received a
total of ve HBO2 treatments within 10 days aer injury.
Treatment and rehabilitation protocol post injury
All subjects underwent treatment assuming that they
would be participating in a competitive match within the
same season. e treatment and rehabilitation protocols
aer injury continued to be non-surgical and included
initial rest, cryotherapy, compression, elevation, and re-
striction of weight bearing in the acute phase within
72 hours [31]. Patients were advised on early rehabilita-
tion, including early range of motion and strengthening
exercise of the quadriceps and hamstrings in a standard
fashion. Weight bearing was permitted as soon as possible
with use of a hinged knee brace when the athlete had mod-
erate or severe pain [31-33]. Finally, aer patients’ muscle
strength, proprioception, agility, and cardiopulmonary
function had recovered to levels that were comparable to
the contralateral side, the patients were permitted to re-
turn to play. e medical sta members for all teams
checked this protocol, and conrmed their treatments
according to this protocol.
Evaluation
Short-term eects of HBO2 therapy on the subjective
evaluation of pain: VAS evaluation
First, in the HBO2 group, VAS scores were used to sub-
jectively evaluate pain. ese scores were compared
immediately before and aer HBO2 therapy on the
same day, which means that we assessed dierences in
the 117-minute treatment. In the VAS evaluation, such
question items of pain at rest, pain while walking, and
pain while jogging were included. VAS scores consisted
of 100 points at full marks, with the worst condition
being 100 points and no complaint being 0 points.
Long-term eects of HBO2 therapy
on time to return to play
Second, time to return to play in the HBO2 (n=16) and
non-HBO2 (n=16) groups was compared. e day of
return to play was determined as the day the athlete
participated in a competitive match. In the non-HBO2
group the time to return to play was retrospectively in-
vestigated through the team medical records, to which
two of the authors had access as medical team doctors.
In addition, we analyzed time to return to play regard-
ing teams and eld positions in all cases (n=32). We also
analyzed time to return to play regarding teams, po-
sitions, number of HBO2 treatments and early or late
application of HBO2 in the HBO2 group (n=16).
Statistical analysis
In this study data were shown as mean ± SD. Statistical
analyses were performed using the Wilcoxon signed rank
test for the VAS evaluation, and the Mann-Whitney U
test for the evaluation of time to return to play between
the HBO2 and non-HBO2 groups, and time to return to
play regarding positions, length of HBO2 treatment time
and early or late HBO2 application. e Kruskal-Wallis
test was performed for the evaluation of time to return
to play among the teams.
All data were analyzed using SPSS version 19.0 (IBM,
Armonk, New York, U.S.). e signicance level for
statistical analysis was set at p<0.05.
RESULTS
Demographics of the subjects
HBO2 group: Mean age of subjects in the HBO2 group
was 27.2 ± 3.3 (range; 22-32) years and all were male.
Subjects in the HBO2 group belonged to these teams:
A (six patients); B (four patients); C (three patients);
or D (three patients) among 14 teams in the top Japa-
__________________________________________________________________________
Table 1. Diagnosis of the grade of MCL injury
__________________________________________________________________________
instability by
manual valgus test tenderness
at full at 30 degrees at the injured
extension of exion MCL site
______________________________________________________________________
Grade 1 (–) (–) (+)
Grade 2 (–) (+) (+)
Grade 3 (+) (+) (+)
__________________________________________________________________________
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UHM 2019, VOL. 46 NO. 5 EFFECTS OF HBO2 ON GRADE 2 MCL INJURY
Yagishita K, Enomoto M, Takazawa Y, et al.
nese rugby league. Rugby positions were distributed as:
11 forwards and ve backs, with the right knee aected
in 8 patients and the le knee aected in eight patients
(Table 2). e mean number of days from injury to the
rst HBO2 session was 2.2 ± 1.4 (range; 0-6) days. Five
HBO2 treatments were recommended. However, average
number of HBO2 sessions was 4.6 ± 0.7 (range; 3-5).
In total, 73 courses of HBO2 were performed in 16
patients (three treatments in two patients, four treat-
ments in three patients, ve treatments in 11 patients).
Non-HBO2 group: Mean age was 27.0 ± 2.0 (range; 24-
31) years and all were male. Subjects in the non-HBO2
group belonged to teams A (six patients) or C (10 patients).
Rugby positions were distributed as follows: six forwards
and 10 backs, with the right knee aected in eight patients
and the le knee aected in eight patients (Table 2). Two
of the authors were medical doctors from teams A and C,
respectively. ey managed the medical protocol and
records including the recovery process and time to re-
turn to play. ere were no statistical dierences in age,
body weight, or height between the HBO2 and non-HBO2
groups.
VAS evaluation in the HBO2 group
We used 58 VAS scores obtained from 13 patients for
analysis, excluding three subjects for whom there was
insucient data. e VAS scores regarding pain at rest
immediately before and aer HBO2 therapy on the same
day were: 18.8 ± 17.7 and 17.3 ± 16.4, respectively (p=0.11),
for pain while walking; 37.4 ± 20.1 and 32.4 ± 21.8, respec-
tively (p<0.001); and for pain while jogging, 50.7 ± 25.6
and 43.9 ± 25.0, respectively (p<0.001) (Figure 1).
Time to return to play between the HBO2 group
and the non-HBO2 group
All subjects were able to participate in a competitive
match aer injury within the same season. Time to
return to play was 31.4 ± 12.2 (range; 10-58) days in the
HBO2 group and 42.1 ± 15.8 (range; 18-71) days in the
non-HBO2 group (Figure 2). ere was a signicant
difference between the two groups (p<0.05).
Time to return to play regarding teams, positions,
number of HBO2 treatments, and early or late
application of HBO2
Regarding time to return to play there were no signicant
dierences among the teams, but there were statistical
dierences between positions (Table 3). Regarding the
number of HBO2 treatments, time to return to play was
21.6 ± 9.6 (range; 10-38) days in the three- or four-
treatment HBO2 group (n=5) and 35.8 ± 9.9 (range;
25-58) days in the ve-treatment HBO2 group (n=11).
ere was a signicant dierence between the groups
(p<0.05). Regarding early or late HBO2 application,
time to return to play was 27.9 ± 9.3 (range; 10-41) days
in the early HBO2 group within two days aer injury
(n=11) and 39.0 ± 13.1 (range; 23-58) days in the delayed
HBO2 group three to ve days aer injury (n=5). ere
were no significant differences between the groups.
DISCUSSION
e healing process of so tissue injury, which includes
MCL injury, is divided into the inammatory or acute,
proliferative, and remodeling phases. In the acute or
inammatory phase, focal injured so tissue is charac-
terized by tissue hypoxia microvascular dysfunction, tissue
ischemia and hypoxia, and edema [5]. HBO2 therapy
can mitigate resolve tissue hypoxia by increasing dis-
solved oxygen tension. MCL injury in the acute phase
is also characterized by edema, pain, and limited range
of motion; hence, rapid reduction of pain and tissue
edema at the injured site in the acute phase could
also accelerate the healing process and return to play.
Skyhar, et al. reported the eects of HBO2 on tissue
edema and necrosis of muscle in the dog compart-
ment model associated with hemorrhagic hypotension.
ey concluded that those ndings might be the results
of improvement of oxygenation of hypoxic tissue and
reduction of edema, which came from reductions in
serum and hematocrit leakage, resorption of extracellular
uid, and improvement in local circulation [11]. ey
mentioned that the mechanisms – i.e., hyperoxygenation
and vasoconstriction [12] – were similar to those of the
_________________________________________________________________________________________________________________________________________________________
Table 2. Patient distribution
_________________________________________________________________________________________________________________________________________________________
position aected side
n age (years) height (cm) body weight (kg) forwards (n) backs (n) right (n) le (n)
_________________________________________________________________________________________________________________________________________________________
HBO2 16 27.2 ± 3.3 (22-32) 182.l ± 9.3 97.3 ± 14.4 11 5 8 8
Non-HBO2 16 27.0 ± 2.0 (24-31) 180.5 ± 7.5 89.0 ± 10.9 6 10 8 8
_________________________________________________________________________________________________________________________________________________________
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Yagishita K, Enomoto M, Takazawa Y, et al.
dog compartment syndrome model in the normotensive
state reported by Strauss, et al.
Using a rat contused skeletal muscle injury model
Oyaizu, et al. reported that HBO2 therapy reduced
muscle wet weight, and decreased the extracellular space
and vascular permeability, which resulted in rapid reduc-
tion of edema [30].
Regarding the eects of HBO2 therapy on ligament
healing, the results of several animal research studies have
been reported. Horn, et al. used a rat model of surgical
MCL laceration with HBO2 therapy exposure at 2.8 ATA
for 1.5 hours a day for ve days aer surgery [15]. Maxi-
mum failure load and stiness at two, four, six and
eight weeks were analyzed. e maximum failure load
and stiness at four weeks in the HBO2 group were statis-
tically greater than in the control group. Moreover, the
HBO2 group reached normal levels at four weeks. How-
ever, the HBO2 group at six weeks was not statistically
dierent from the control group, which suggested that
HBO2 therapy accelerated the return to normal ligament
level.
Mashitori, et al. created a 2-mm segment of MCL in a
rat model and applied HBO2 therapy at 2.5 ATA for two
hours a day for ve days. Maximum failure load and
type I procollagen gene expression at 14 days in the
HBO2 groups statistically increased in conjunction with
HBO2 application[16]. Ishi, et al. examined the eects
of three dierent HBO2 exposures on the healing of rat
patellar ligament injury: HBO2 exposures included 1.5
ATA for 30 minutes, 2.0 ATA for 30 minutes, and 2.0
ATA for 60 minutes once a day and for 10 sessions. Aer
two weeks, HBO2 therapy at 2.0 ATA for 60 minutes was
___________________________________________________________________________
FIGURE 1
VAS scores immediately before HBO2 and after HBO2
___________________________________________________________________________
FIGURE 2
Time to return to play in the non-HBO2 and HBO2 groups
___________________________________________________________________________ ___________________________________________________________________________
§: p<0.05
*: p<0.001
___________________________________________________________________________ ___________________________________________________________________________
____________________________________________________________________________________________________________________________________________________________
Table 3. Time to return to play regarding the teams and positions
____________________________________________________________________________________________________________________________________________________________
HBO2 non-HBO2
Team Number Forwards (n) Backs (n) subtotal Number Forwards (n) Backs (n) subtotal
____________________________________________________________________________________________________________________________________________________________
A 6 27.3±11.0 (4) 43.5±5.5 (2) 32.5±12.0 (6) 6 52.0±19.0 (2) 40.3±11.3 (4) 44.2±15.4 (6)
____________________________________________________________________________________________________________________________________________________________
B 4 25.5±2.5 (2) 26.5±3.5 (2) 26.0±3.1 (4)
____________________________________________________________________________________________________________________________________________________________
C 3 31.5±6.5 (2) 58 (1) 40.3±13.6 (3) 10 42.5±14.5 (4) 39.7±15.3 (6) 40.8±15.1 (10)
____________________________________________________________________________________________________________________________________________________________
D 3 27.3±11.0 (3) 27.3±11.0 (3)
____________________________________________________________________________________________________________________________________________________________
Total 16 27.6±26.6 (11)* 41.2±12.0 (5)* 31.4±12.2 (16) 16 45.7±16.7 (6) 39.9±13.9 (10) 42.1±15.8 (16)
____________________________________________________________________________________________________________________________________________________________
statisitical dierence between forwards and backs *: p<0.05 (average ± SD days)
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UHM 2019, VOL. 46 NO. 5 EFFECTS OF HBO2 ON GRADE 2 MCL INJURY
Yagishita K, Enomoto M, Takazawa Y, et al.
the most eective, resulting in enhanced extracellular
matrix deposition as measured by collagen synthesis
[17]. Possible mechanisms of action of HBO2 on ligament
injury include reduction of edema and swelling, and
promotion of broblast proliferation in the scar tissue
to produce more type I procollagen mRNA[16].
Clinical reports of the time loss due to MCL injury
had been variously documented. e time loss in grades
2 and 3 MCL injury in the U.S. Military Academy study
was reported as 29 days [2], and the Union of European
Football Association injury study reported 23 ± 23 days
of layo time in 346 MCL injuries [34]. Derscheid, et
al. reported a mean return to football within 20 days in
patients with grades 1 or 2 MCL injuries who were treated
non-operatively [35]. Regarding rugby, especially in high-
level rugby players at a professional or semi-professional
level, Dallalana, et al. reported knee injuries in the English
professional rugby union, and documented a time loss of
41 days in grade 2 MCL injury [1].
However, clinical data is scarce regarding the short- and
long-term eects of HBO2 therapy in patients with MCL
injury. Moreover, little is known regarding its eect in
accelerating recovery time. Only Soolsma reported the
eects of HBO2 therapy on functional recovery during
the fourth, h and sixth week aer injury using a double-
blind controlled study. However, this study has not been
published as an original article but only as a university
report [28].
is study is the rst clinical report regarding the short-
term eects of HBO2 therapy on subjective symptoms
and the long-term eect of HBO2 therapy on return to
play, comparing an HBO2 group with a non-HBO2 group.
Time to return to play is inuenced by many factors,
including the athletic event; eld position; circumstances
of schedule; other conventional treatment protocols,
including RICE (rest, ice, compression and elevation)
treatment at the acute phase; and post-injury rehabili-
tation protocol. In this study, in order to minimize the
eect of subject bias, all subjects were professional or
semi-professional rugby players who belonged to the
same top category of the Japanese Rugby Federation.
In this study, the VAS scores regarding pain while
walking and jogging were signicantly reduced, which
indicated an increase in the short-term eect of HBO2
therapy. e VAS scores for pain at rest were not signi-
cantly dierent between immediately before and aer
HBO2 therapy, but the VAS scores while walking and
jogging were signicantly dierent. Walking and
bending the knee joint increased the tissue pres-
sure, and this increase exacerbated the knee pain
around the MCL. HBO2 application helps reduce ede-
ma and tissue pressure and would have eects on re-
duction of VAS scores during walking and jogging.
e time to return to play in the non-HBO2 group was
42.1 days, which is consistent with the Dallalana, et al.
report on conventional treatment in professional rugby
players. us, it was considered that the control group
of non-HBO2 therapy in this study was suitable, and the
time to return to play of 31.4 days in the HBO2 group
was judged as signicantly valuable data in regard to the
long-term eects of HBO2 therapy on the acceleration of
recovery. Regarding number of HBO2 treatments, there
was a signicant dierence between the three- or four-
treatment HBO2 group and the ve-treatment HBO2
group. We speculated that the subjects in the ve-
treatment HBO2 group might include cases of greater
severity.
LIMITATIONS
We recognize several limitations of this study. First, this
was not a prospective comparative study, and it is not
possible to exclude that factors related to the interven-
tion, including a possible placebo eect, may have con-
founded the results. e number of subjects was small, and
the injury periods of the HBO2 and non-HBO2 groups
were dierent. e subjects in this study belonged to the
top-level category; however, the HBO2 group included
four teams, whereas the non-HBO2 group included only
two teams. e results showed the wide range of recovery
time, which might include mild and severe cases of
grade 2 MCL injury for the subjects in this study. In
addition, it will be necessary to examine dierences
in the eects of HBO2 therapy on injured tissue com-
pared to non-injured healthy tissue, as well as conven-
tional therapies such as RICE treatment and/or use of
orthotics.
e VAS evaluations immediately before and aer
HBO2 therapy had the possibility to show only the
eects of the 117-minute rest. e VAS scores of the
patients who had not received HBO2 and simply had
117 minutes of rest would be more appropriate as a
control. In addition, the VAS evaluation in the non-HBO2
limb would be performed hopefully for comparing the
eects of HBO2 on the healthy limb and injured limb in
the future.
HBO2 can have positive eects on MCL injuries. How-
ever, practitioners should be cautious in using HBO2
therapy for off-label sports medicine injuries.
653
UHM 2019, VOL. 46 NO. 5 EFFECTS OF HBO2 ON GRADE 2 MCL INJURY UHM 2019, VOL. 46 NO. 5 EFFECTS OF HBO2 ON GRADE 2 MCL INJURY
CONCLUSION
We examined the eects of HBO2 therapy on professional
or semi-professional Japanese rugby players with grade 2
MCL injury that occurred during sports activities. HBO2
therapy could have a short-term eect on pain reduction
during the acute phase, and a long-term eect on acceler-
ation of recovery with a decreased time to return to play.
n
Acknowledgments
We would especially like to thank Mr. Masuhide Udono
and Mr. Masahiro Furudate for their communication of
information on athletes, and all the medical engineers of
Hyperbaric Medical Center at Tokyo Medical and Dental
University for supporting this study.
Conicts of interest and source of funding statement:
Kazuyoshi Yagishita has received scientic grant from
YMFS YAMAHA Sports Challenge Fund.
For the remaining authors none were declared.
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... In the knee, hyperbaric oxygen therapy for grade 2 medial collateral ligament (MCL) sprains (Yagishita et al., 2019), surgical reconstruction of anterior cruciate ligament (ACL) sprains (Takazawa et al., 2016) and conservative management of posterior cruciate ligament (PCL) sprains were investigated to facilitate RTP in tackle-collision sport athletes (Toritsuka et al., 2004). The rehabilitation protocols involved progressive WB and quadriceps strengthening (Takazawa et al., 2016;Toritsuka et al., 2004;Yagishita et al., 2019). In addition, knee ROM, strengthening of surrounding areas (Toritsuka et al., 2004;Yagishita et al., 2019), functional training and sport specific drills (Takazawa et al., 2016) were included in selected studies. ...
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... Yagishita et al. (59) published a nonrandomized study involving 32 semiprofessional or professional rugby players that had sustained a grade 2 MCL strain (as diagnosed by MRI and physical examination). Sixteen players were selected for HBOT treatments and the other 16 underwent standard rehabilitation alone. ...
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Passive recovery techniques are popular and offer a diverse spectrum of options for athletes and the clinicians providing care for them. These techniques are intended to minimize the negative effects of training or competition, thus enabling the athlete a quicker return to peak performance. Current evidence demonstrates improved athlete recovery with compression garments, cold water immersion, partial body cryotherapy, hyperbaric oxygen, and vibratory therapies. Other popular modalities, such as compression devices, whole body cryotherapy, percussive gun-assisted therapy, neuromuscular electrical stimulation, and pulsed electromagnetic therapy lack convincing evidence concerning athlete recovery. This article seeks to review the current literature and offer the reader an updated understanding of the mechanisms for each modality and the evidence regarding each modality's potential benefit in an athlete's recovery strategy.
... Moreover, no difference was made between grade I and II injuries, where weight bearing and ambulation are tolerated, and muscle strengthening and range of motion (ROM) exercises are performed 'in a standard fashion'. 46 For grade III injuries, partial weight bearing has been recommended up to 4 weeks after injury. The overall description of the quality of rehabilitation protocols is very low, and details of exercise therapy have not been given. ...
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Knee injury negatively impacts routine activities and quality of life of millions of people every year. Disruption of tendons, ligaments, and articular cartilage are major causes of knee lesions, leading to social and economic losses. Besides the attempts for an optimal recovery of knee function after surgery, the joint healing process is not always adequate given the nature of intra-articular environment. Based on that, different therapeutic methods attempt to improve healing capacity. Hyperbaric oxygen therapy (HBOT) is an innovative biophysical approach that can be used as an adjuvant treatment post-knee surgery, to potentially prevent chronic disorders that commonly follows knee injuries. Given the well-recognized role of HBOT in improving wound healing, further research is necessary to clarify the benefits of HBOT in damaged musculoskeletal tissues, especially knee disorders. Here, we review important mechanisms of action for HBOT-induced healing including the induction of angiogenesis, modulation of inflammation and extracellular matrix components, and activation of parenchyma cells-key events to restore knee function after injury. This review discusses the basic science of the healing process in knee injuries, the role of oxygen during cicatrization, and shed light on the promising actions of HBOT in treating knee disorders, such as tendon, ligament, and cartilage injuries.
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Background: A medial collateral ligament (MCL) knee sprain is a prevalent injury in athletic populations that may result in significant time lost to injury. Remarkably little is known of the epidemiology of this injury. Purpose: To define the incidence of MCL tears and to determine the demographic and athletic risk factors. Study design: Descriptive epidemiological study. Methods: A longitudinal cohort study was performed to examine the epidemiology of isolated MCL sprains at the United States Military Academy (USMA) between 2005 and 2009. Charts and radiographic studies were reviewed by an independent orthopaedic surgeon to identify all new isolated MCL sprains resulting in time lost to sport and activity that occurred within the study period. Incidence rates (IRs) with 95% confidence intervals (CIs) were calculated per 1000 person-years at risk and by sex, sport, and level of competition. The IR per 1000 athlete-exposures (AEs) was also determined. Incidence rate ratios (IRRs) and respective 95% CIs were calculated between male and female students, intercollegiate and intramural athletes, and male and female intercollegiate athletes involved in selected sports. Chi-square and Poisson regression analyses were used to examine the relationship between the variables of interest and the incidence of MCL sprains, with statistical significance set at P < .05. Results: A total of 128 cadets sustained isolated MCL injuries during 17,606 student person-years from 2005 to 2009. This resulted in an IR of approximately 7.3 per 1000 person-years. Of the 128 injuries, 114 were in male athletes (89%) and 14 were in female athletes (11%). Male cadets had a 44% higher IR than did female cadets (7.60 vs 5.36, respectively), although this was not significant (P = .212). Of 5820 at-risk intercollegiate athletes, 59 (53 male, 6 female) sustained an isolated MCL sprain during 528,523 (407,475 male, 121,048 female) AEs for an overall IR of 10.14 per 1000 person-years and 0.11 per 1000 AEs. The IRR of MCL sprains of men compared with women involved in intercollegiate athletics was 2.87 (95% CI, 1.24-8.18) per 1000 person-years and 2.62 (95% CI, 1.13-7.47) per 1000 AEs. Of 21,805 at-risk intramural athletes, with quarterly participation, 16 (all male) sustained isolated MCL injuries during 225,683 AEs for an overall IR of 0.07 per 1000 AEs. The IRs of MCL injuries of intercollegiate and intramural athletes did not differ significantly. In intercollegiate sports, wrestling (0.57), judo (0.36), hockey (0.34), and rugby (men's, 0.22; women's, 0.23) had the highest IRs per 1000 AEs. When examining men's intercollegiate athletics, the IRRs of wrestling (13.41; 95% CI, 1.80-595.27) and hockey (8.12; 95% CI, 0.91-384.16) were significantly higher compared with that of lacrosse. Among women's intercollegiate sports as well as intramural sports, there were no significant differences in IRs. A median of 16 days was lost to injury, with 2407 total days lost for all injuries. Grade 1 MCL injuries lost a median of 13.5 days, while higher grade injuries lost a median of 29 days. Conclusion: Medial collateral ligament injuries are relatively common in athletic cohorts. The most injurious sports are contact sports such as wrestling, hockey, judo, and rugby. Male athletes are at a greater risk than female athletes. Intercollegiate athletes are at a greater risk than intramural athletes. The average amount of time lost per injury was 23.2 days, with greater time lost with higher grade sprains than grade 1 sprains.
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Recently, the use of hyperbaric oxygen (HBO) treatments by elite athletes to accelerate recovery from muscle injuries has become increasingly popular. However, the mechanism of promoting muscle regeneration under HBO conditions has not yet been defined. In this study, we investigated whether HBO treatments promoted muscle regeneration and modulated muscle regulatory factor expression in a rat skeletal muscle injury model. Muscle injury was induced by injecting cardiotoxin (CTX) into the tibialis anterior (TA) muscles. As the HBO treatment, rats were placed in an animal chamber with 100% oxygen under 2.5 atmospheres absolute for 2 h/day, 5 days/week for two weeks. We then performed histological analyses, measured the maximum force-producing capacity of the regenerating muscle fibers and performed quantitative RT-PCR analysis of muscle regulatory factor mRNAs. The cross-sectional areas and maximum force-producing capacity of the regenerating muscle fibers were increased by HBO treatment after injury. The mRNA expression of MyoD, Myogenin and IGF-1 increased significantly in the HBO group at 3 and 5 days after injury. The numbers of Pax7(+)/MyoD(+), Pax7(-)/MyoD(+) and Pax7(+)/BrdU(+)-positive nuclei were increased by HBO treatment. In this study, we demonstrated that HBO treatment accelerated satellite cell proliferation and myofiber maturation in rat muscle that was injured by a CTX injection. These results suggest that HBO treatment accelerates healing and functional recovery after muscle injury.
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Purpose: U.S. high school athletes sustain millions of injuries annually. Detailed patterns of knee injuries, among the most costly sports injuries, remain largely unknown. We hypothesize that patterns of knee injuries in U.S. high school sports differ by sport and sex. Methods: U.S. high school sports-related injury data were collected for 20 sports using the National High School Sports-Related Injury Surveillance System, High School RIO™. Knee injury rates, rate ratios (RR), and injury proportion ratios were calculated. Results: From 2005/2006 to 2010/2011, 5116 knee injuries occurred during 17,172,376 athlete exposures (AE) for an overall rate of 2.98 knee injuries per 10,000 AE. Knee injuries were more common in competition than in practice (rate ratio = 3.53, 95% confidence interval [CI] = 3.34-3.73). Football had the highest knee injury rate (6.29 per 10,000 AE) followed by girls' soccer (4.53) and girls' gymnastics (4.23). Girls had significantly higher knee injury rates than boys in sex-comparable sports (soccer, volleyball, basketball, baseball/softball, lacrosse, swimming and diving, and track and field; RR = 1.52, 95% CI = 1.39-1.65). The most commonly involved structure was the medial collateral ligament (reported in 36.1% of knee injuries), followed by the patella/patellar tendon (29.5%), anterior cruciate ligament (25.4%), meniscus (23.0%), lateral collateral ligament (7.9%), and posterior cruciate ligament (2.4%). Girls were significantly more likely to sustain anterior cruciate ligament injuries in sex-comparable sports (RR = 2.38, 95% CI = 1.91-2.95). Overall, 21.2% of knee injuries were treated with surgery; girls were more often treated with surgery than boys in sex-comparable sports (injury proportion ratio = 1.30, 95% CI = 1.11-1.53). Conclusions: Knee injury patterns differ by sport and sex. Continuing efforts to develop preventive interventions could reduce the burden of these injuries.
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The medial collateral ligament (MCL) is one of the most extensively studied ligaments in our literature. This is due to the fact that it is the most commonly injured ligament of the knee and it is easily defined and mechanically studied in animal models. The purpose of this article is to (1) review the MCL' s response to injury, (2) evaluate the ligament's injury variables, and (3) take an in depth look at treatment options including past, present, and future.
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Crush injuries represent a spectrum of injury to body parts as result of trauma. Presentations vary from minor contusions to limb-threatening damage. Typically, the injury involves multiple tissues, from skin and subcutaneous, to muscle and tendons, to bone and joints. In their most severe presentations, predictable complications--including osteomyelitis, non-union of fractures, amputations and failed flaps--occur in approximately 50 percent of the cases with standard of practice surgical and medical interventions. Skeletal muscle-compartment syndrome (SMCS) is another consequence of trauma, but in this situation the target tissues are muscles and nerve. Edema and/or bleeding within the confines of the fascial envelope can increase the pressure within the skeletal muscle-compartment. When the tissue fluid pressure within the compartment exceeds the capillary perfusion pressure to the muscles and nerves in the compartment, these tissues are rendered ischemic and manifest the signs and symptoms of SMCS. The SMCS, especially in its incipient stages before a fasciotomy is required, is a therapeutic challenge since no means to arrest its progression exist other than hyperbaric oxygen (HBO2). Unfortunately, HBO2 is woefully neglected as an adjunct for managing crush injury and SMCS. Strong arguments exist for its use based on evidenced-based information and how HBO2 mitigates the pathology of these conditions.