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Recreational Injury Interventions
Knee Braces and Other Orthotics
Background
Knee injuries are a common occurrence in
a variety of sports. Football is no exception; the most common knee injuries are
ligament injuries (grades I-III) with the medial collateral ligament (MCL) the most
commonly sprained.6 The knee is the most frequent injury site in
football constituting 18-23% of all football injuries in high school and college.7 Use of knee braces is a common prophylactic measure.
Studies which evaluated the effectiveness of braces are reviewed below. Unfortunately,
none of these studies is a randomized control trial.
Review of knee brace studies:
Author | Zemper, 1990 |
Study design and target population | Prospective cohort study.
Population: 5% proportionally representative
sample of NCAA/NAIA collegiate football teams 1986-1987 seasons. Data obtained
from National Sports Injury Surveillance System (NSISS). |
Intervention | Knee braces of all types |
Outcomes | Total injuries, knee injuries, MCL injuries, time lost
from practice and games |
Results | 6,229 players; 445,856 AE (athlete exposures). 1,744
players (28%) wore knee braces.
All injuries:
6.3 per 1000 AE (3.9 per 1000 AE in
practices and 33.9 per 1000 AE in games)
521 knee injuries, 1.2 per 1000 AE.
Those wearing braces had an increased
risk of knee injury, RR 1.42 (1.2-1.8) compared to nonbraced players. MCL
injuries were not significantly increased in braced players RR=1.2 (0.8- 1.9)
Days lost from participation for all knee and MCL injuries were significantly
different from those not wearing braces. Results followed the same pattern
when game injuries were analyzed separately. Braces had no impact on ankle
injuries; incidence of injury the same for contact and non-contact situations.
Interaction found between braces and artificial turf resulting in increased
MCL injuries when playing on turf and wearing braces. |
Study quality and conclusions | Analysis of 2 years of data from the nationwide sports
database (NSISS) shows no protective effect of knee braces for football injuries.
All data were analyzed using chi-square comparisons.
A larger sample size is needed to carry out multivariate analyses. In order
to isolate the effect of knee braces it will be necessary to adjust for practice/training
methods, practice and playing surfaces (grass vs. astroturf), player position
and conditioning and playing time. |
Author | Grace et al., 1988 |
Study design and target population | Prospective cohort study.
Population: AAAA high school football players
in Albuquerque and Santa Fe NM.
N=580 players over 2 seasons |
Intervention | Single upright single-hinged and double-hinged braces. |
Outcomes | Knee sprains and strains and lower extremity (LE) injuries.
Classified using modified National Athletic Injury/Illness Reporting System
(NAIRS) based on time lost from practice and competition. Grades 0-IV. |
Results | For the analysis braced and nonbraced players were
matched by size, weight and playing position. Results of McNemar chi-square
for matched data indicate
3.7 times more injuries in players wearing single hinged
braces compared to non-braced players (p<0.001). Increased severity and
rate of injury in wearers of double braces, but not significant. Lower leg
and ankle injuries 3 times more common in braced players, p<0.01. Crude
relative risk for knee and LE calculated from Table II: RR for knee injuries=3.4
(1.7-7.2) comparing all braced players to nonbraced players and RR for lower
extremity injuries=3.8 (1.6-8.8) |
Study quality and conclusions | Single-upright, single-hinged prophylactic knee braces
associated with significantly increased rate of injury. Double hinged braces
did not decrease the incidence of injuries. Both types of braces were associated
with increased injuries of the ipsilateral ankle and foot. |
Author | Shaw et al., 1987 |
Study design and target population | Before/after study design.
Population: junior varsity and varsity football
players. Texas City High School, Texas City, TX |
Intervention | Single sided brace (McDavid)
1983-no braces worn
1984-varsity fit with bilateral braces
1985-braces provided for all players.
Wearing brace not mandatory |
Outcomes | Knee injuries requiring surgical/physician care or
time lost due to injury. |
Results | Knee injuries declined from 19 to 6 per season over
4 year period (1983-86). Time lost declined from 143 days to 53 days per season.
Number or percentage of players wearing braces not given. |
Study quality and conclusions | Data presented was incomplete and no denominators were
given (number of players, practices or games)
Coaching staff, team physician and
athletic trainer unchanged for period of study. |
Author | Rovere et al., 1987 |
Study design and target population | Before/after study design.
Population: Football players, Wake Forest
University, 1983-85 |
Intervention | Anderson Knee Stabilizer. Double hinged single sided
brace. All players required to wear brace for practice and games, 1983-85. Comparison
(no brace period), 1981-82. Two fall and two spring seasons included in each
group |
Outcomes | Grade I, II, III knee sprains as diagnosed by orthopedic
surgeon. |
Results | Increased injuries in players wearing braces. 7.5 per
100 players with braces vs 6.1 per 100 players not braced. Total number of players
not specified, relative risk calculated from above proportions. RR=1.2 (0.7-2.1)
Majority of injuries Grade I MCL sprains 4.8 per 100 players braced vs. 4.0
per 100 players braced.
Relative frequency of injury by player position unchanged.
|
Study quality and conclusions | Non-significant increase in knee injuries when braces
used.
No change in coaching practices over 2 year period.
|
Author | Teitz et al., 1987 |
Study design and target population | Prospective cohort study.
Population: NCAA Division I varsity football
players, 1984 and 85 seasons. |
Intervention | Knee braces
Types included were: McDavid, Omni/Anderson,
Jon Joy, American Prostheses |
Outcomes | Incidence and severity of knee injuries |
Results | 1984: 6,307 players, 2297 (36%) braced.
1985: 5,390 players, 2389 (44% braced).
All knee injuries higher in players
wearing braces; 11 per 100 players braced vs 6 per 100 players nonbraced (1984)
and 9.4 vs 6.4 per 100 players, braced vs nonbraced for 1985. p<0.001
MCL injuries more common in braced
players (for 1984, 7.6 compared to 3.5 percent; for 1985 5.4 compared to 3.6
percent). Subset analyses conducted to evaluate incidence of injury between
braced and nonbraced players for the following: player position, playing surface,
mechanism of injury (contact/no contact), skill level (varsity string). Severity
of injury was based on loss of playing time, specific grading of MCL injuries,
and injuries requiring surgery. No difference in injury severity was found
between braced and nonbraced players. |
Study quality and conclusions | Preventive braces are not preventive and may be harmful.
The consistency of the data from year to year and the corroboration of the overall
findings by the results of subset analysis strongly support this conclusion. |
Author | Hewson et al., 1986 |
Study design and target population | Before/after study design
Population: University of Arizona intercollegiate
football players, 1977-1985 |
Intervention | Knee brace (Anderson knee stabler)
1977-80 no brace used
1981-1985 mandatory braces for all
"at risk" players (offensive and defensive linemen, linebackers,
tight ends) |
Outcomes | Number, type and severity of knee injuries.
Exposure defined as attendance at a
practice or game. |
Results | 28,191 braced exposures (224 players) and
29,293 non-braced exposures (226 players).
No statistically significant difference
between braced and nonbraced players for knee injury rate, injury type or
severity. |
Study quality and conclusions | Prophylactic knee bracing did not prevent knee injuries.
NCAA rule changes and changes in treatment techniques
beginning in 1981 designed to reduce knee injuries. |
Author | Hansen et al., 1985 |
Study design and target population | Retrospective cohort study.
Population: University of Southern California
(USC) football players (1980-1984) |
Intervention | Knee braces (Anderson Knee Stabler) |
Outcomes | Number and type of knee surgeries.
Outcome determined by review of team’s
medical records. |
Results | 477 players; 148 (31%) braced. 11% injury rate in nonbraced
group; 5% injury rate in braced group.
4% of braced linebackers were injured
vs 25% of nonbraced linebackers. Similar results for offensive and defensive
linemen. |
Study quality and conclusions | Authors recommend Anderson brace for linebackers and
interior linemen at USC.
Simplistic analysis. Results based on small
numbers of injuries; no confidence intervals given. No information on characteristics
of players, or any other confounders. Self-selected brace use. |
Summary of knee brace/orthotic
studies
The studies reviewed above provide conflicting
results on the protective effect of knee bracing. Some smaller studies and studies
involving only one team have found braces protective,10,14 while other single school studies
found no protective effect or a non-significant increase in injuries.11,13 Two nation wide studies of collegiate
athletes found no evidence that braces offered protection from knee injuries.8,12 There are a wide variety of
factors which can contribute to knee injuries. Some of these (i.e., playing surfaces,
shoes, player position, mechanism of injury, history of previous injury) can be
analyzed directly. Other factors (particularly player conditioning, coaching methods,
rules, treatment, and natural fluctuation in the incidence of injury) are more difficult
to measure. Large national studies which were able to evaluate injury rates in different
sub groups of players provide the best evidence available to date.8,12
Recommendations
on knee braces and other orthotics
At the present time prophylactic use of knee braces does not appear to protect
players from knee injuries. Studies which found an increased risk of injury with
knee braces may simply be reflecting the fact that individuals with prior knee injuries—who
are most at risk of re-injury—are also the ones who wear braces.
Recommendations for future research
There is a definite need for well-designed, large-scale randomized controlled trials
(RCTs) to evaluate the protective effect (if any) of knee bracing. This is the only
way that all the other confounders can be controlled for.
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