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Conservative Management
of Chronic Ankle Instability
Adam Ajis, MBBS, MRCSEd,
Nicola Maffulli, MD, MS, PhD, FRCS (Orth)*
Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine,
Thornburrow Drive, Hartshill, Stoke on Trent ST4 7QB Staffs, United Kingdom
The mechanism of injury of lateral ankle sprains is usually a forced inver-
sion injury with the tibiotalar joint in plantar flexion. Up to 20% of lateral
ankle sprains progress to functional instability [1].
Inversion injuries of the ankle account for up to 25% of all musculoskel-
etal injuries [2]. Despite the high incidence, there is still some contention
about the optimal method of management. Proposed management modali-
ties include surgical repair/reconstruction, rigid/semirigid casting, bracing,
elastic bandaging, strapping, ultrasound, temperature contrast baths, elec-
tric current therapy, hyperbaric oxygen, oral anti-inflammatories, oral pro-
teolytic enzymes, and injectable steroids [3]. These options are usually
combined with rest, compression, ice, and elevation. Conservative manage-
ment involves one or more of the above modalities within a program of ei-
ther strict immobilization or early controlled movement and rehabilitation
[3]. This article discusses some of the conservative management modalities
described in the literature.
Types of instability
Two types of ankle instability are described, namely functional and me-
chanical. Mechanical instability is abnormal laxity of the ligamentous re-
straints, and is a sign. Functional instability refers to abnormal function,
with recurrent episodes of the ankle giving way, and is a symptom. The
two types of instability can exist independently of one another, but often
occur together. Indeed, a patient can have minimal mechanical instability
* Corresponding author.
E-mail address: n.maffulli@keele.ac.uk (N. Maffulli).
1083-7515/06/$ - see front matter Ó2006 Elsevier Inc. All rights reserved.
doi:10.1016/j.fcl.2006.07.004 foot.theclinics.com
Foot Ankle Clin N Am
11 (2006) 531–537
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(ie, minimal laxity) and report giving way, that is, functional instability.
Therefore, the terms ‘‘laxity’’ and ‘‘instability’’ should not be used
synonymously.
Clinical features
Anatomy
In neutral position, the tight fit of the talus between the tibia and fibula
stabilize the ankle joint [4]. The compressive loads imposed under weight
bearing enhance osseous stability [4]. With increasing plantar flexion, the os-
seous constraints are lessened, and the soft tissues are more susceptible to
strain and injury [4].
The lateral ankle joint ligamentous complex consists primarily of three
structures: the anterior talofibular ligament (ATFL), the calcaneofibular lig-
ament (CFL), and the posterior talofibular ligament (PTFL) (Fig. 1).
The ATFL is the most anterior structure, and is the weakest and most
easily injured of these ligaments [5]. The ATFL is often described as a thick-
ening of the lateral joint capsule [6]. When the foot is plantar flexed, the
ATFL is vertical, and is the primary stabilizing structure of the ankle during
an inversion stress.
The CFL is a round, cord-like extracapsular structure that originates
from the inferior distal surface of the fibula, extends posteroinferiorly,
deep to the peroneal tendons, and attaches on a small tubercle on the pos-
terior aspect of the lateral calcaneal surface. The CFL is vertical when the
Fig. 1. The ligamentous complex of the lateral aspect of the ankle.
532 AJIS & MAFFULLI
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foot is dorsiflexed, when it becomes the primary ankle stabilizer and second-
ary subtalar joint stabilizer. Isolated injuries of the CFL are rare.
The PTFL is the strongest and least vulnerable of the three ligaments;
isolated ruptures are extremely rare. It is most commonly injured in severe
ankle sprains after the ATFL and CFL have been disrupted. It is a trape-
zoid-shaped structure, which originates from the distal portion of the digital
fossa of the fibula and inserts on the posterolateral tubercle of the talus, and
on the os trigonum when present.
History
Most patients give a clear history of one or more ankle injuries. However,
some patients, especially those with varus or cavovarus foot, may develop
symptoms of ankle instability without injury [3]. Typically, patients com-
plain of repeated giving way of the ankle. Swelling and pain may accompany
giving way, which is often commoner on slopes or uneven ground.
Examination
It is important to identify the underlying causes of instability. In partic-
ular, the overall foot shape should be evaluated, looking particularly for
hindfoot varus, and adequate neurologic examination should be performed.
The shoes will give information on heel contact. Generalized joint laxity
should be sought.
Tenderness is usually maximal over the lateral ligament, often over the
ATFL only. A few patients, normally those with more complex injuries,
also have localized tenderness over the deltoid ligament. Some patients
have rather generalized joint line tenderness, palpable synovitis, or an effu-
sion. Tenderness or swelling over the Achilles, peroneal, or tibialis posterior
tendons should be identified. There is an association between ankle instabil-
ity and peroneal tendon instability: patients will usually complain of snap-
ping or giving way over the peroneal tendons, and instability is maximal
on plantar flexion and eversion.
Laxity is demonstrated with the anterior draw and tilt tests. The ante-
rior draw test should be performed with the ankle in 20of plantar flexion
[7]. The tibia may be pushed posteriorly against the fixed foot, or the foot
can be drawn forward. The characteristic positive sign is a ‘‘suction sign,’’
as the synovium is sucked into the joint, drawing the skin inward in the
lateral gutter. However, in many patients there is no suction sign, but
the talus can obviously be drawn anteriorly more than on the contralateral
side. Tohyama and colleagues [8] showed in cadavers that 30 N force pro-
duced more difference in displacement between injured and normal sides
than 60 N.
The talar tilt test is conventionally performed by tilting the hindfoot and
looking for a suction sign or asymmetric movement. The ankle should be in
533CONSERVATIVE MANAGEMENT OF CHRONIC ANKLE INSTABILITY
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physiologic plantar flexion [7]. Palpation of the talar neck will assist in dif-
ferentiating between movement in the ankle and the subtalar joint.
There may well be no great correlation between mechanical stability
(ie, laxity) and functional stability. Therefore, a patient may present with great
laxity, and report no or very little instability. In these patients, the role of
surgery is dubious, and conservative management is probably a safe option.
Imaging
Plain anteroposterior and lateral radiographs of the ankle are generally ob-
tained to evaluate the joint and ascertain the presence of associated injuries.
Obtaining these films with the patient standing allows accurate assessment
of joint space and alignment. In patients with cavus or cavovarus feet, a stand-
ing hindfoot alignment view can be done, which differentiates between mala-
lignment within and below the ankle [9]. Standing lateral and dorsoplantar
views of the foot allow further evaluation of possible associated deformity.
Stress radiography is the ‘‘gold standard’’ for detecting mechanical ankle
instability. However, there has been wide variation in the criteria for diag-
nosing instability. Karlsson and colleagues [10] performed a most compre-
hensive study, establishing criteria for radiographic instability of an
anterior draw of 10 mm or more, or a talar tilt of 9or more. If an opposite
stable ankle was available for comparison, an anterior draw of 3 mm or a ta-
lar tilt of 3more than the other side would be significant. However, as the
management of acute ankle sprains is based on functional nonoperative mo-
dalities, and does not depend on the degree of ankle instability on stress
views, stress radiographs have no clinical relevance in the acute situation.
In cases of functional instability, the large variability in both injured and
noninjured ankles precludes their routine use [11].
Magnetic resonance imaging may be used in preoperative planning if
doubts still persist.
Conservative management
Most studies on surgery for chronic ankle instability comment that ‘‘the
patients had full nonsurgical management before being considered for sur-
gery’’: this is considered good practice [12,13].
However, only one published series examined the effect of functional re-
habilitation on chronic instability. Karlsson [14] found that 50% of patients
with chronic instability benefited from a structured rehabilitation program.
Patients with mechanical instability were less likely to benefit than those
with purely functional instability.
Modalities
Conservative management of patients with functional ankle instability
follows the paradigm typical of acute management of soft tissue injuries,
534 AJIS & MAFFULLI
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using the RICE principles. Peroneal strengthening, proprioceptive training,
lateral heel wedges, bracing and strapping are the main modalities of ankle
rehabilitation [15–17]. Lateral heel wedges and Achilles tendon stretching
are helpful in preventing hindfoot malpositioning that leaves lateral liga-
ments prone to injury [18]. Proprioceptive training and peroneal strengthen-
ing work by stabilizing the ankle and hindfoot through improvement in
maintaining ankle position when external forces are applied to it. After pro-
prioceptive training, patients are less likely to allow the ankle to adopt a po-
sition that makes it more vulnerable to injury [17–19]. Proprioception
training can be performed using an ankle tilt board [20]. Improved ankle
proprioception leads to better dynamic ankle joint stability, and has a pro-
tective role against future sprains [21].
Peroneal muscle reaction times were significantly longer in patients with
ankle instability [19]. Patients probably recruit their peroneal musculature
slightly later, and cannot protect themselves from further inversion and in-
jury. The same study found that training, taping, and external immobiliza-
tion work to restrict the extremes of motion and shorten peroneal muscle
reaction time. This was not statistically significant [19].
Ankle braces have been widely used to compensate for instability. Those
braces that provide adequate support clinically tend to be too bulky, and are
thus unpopular with athletes [22]. Aircast (UCBL, Summit, New Jersey) and
similar devices are helpful but tend to be too limiting, so, again, cannot be
used for sports [15]. The canvas lace-up style brace, Swede-O (North
Branch, Minnesota), for example, is less cumbersome, but is less supportive.
Other Velcro style straps such as Wrip Wrap (Norco, California) or neo-
prene sleeves like Pro Orthopaedic (Tuscon, Arizona), provide some sup-
port. However, the support provided by these means is no more effective
that ordinary ankle taping [15]. Mann [15] proposed a custom thermomold
cup with a combination hindfoot brace that has yielded good results despite
the need for multiple adjustments before proper fit.
Rehabilitation exercises are an important part of conservative manage-
ment, and should continue for at least 2 to 3 months [23]. For chronic insta-
bility, two consecutive phases of rehabilitation are advocated, namely
functional and prophylactic [23]. Initially in the functional phase, all exer-
cises and activities should be pain and symptom free, and be weight bearing
and multidirectional [23]. In the prophylactic phase, again, multidirectional
movements and strengthening of all muscle groups around the ankle should
occur. Emphasis should be put on performing the exercises with the ankle in
plantar flexion and inversion, with the joint being progressively stressed to
meet the demands imposed on it [23]. There may be a role for ankle tap-
ing/bracing in the prophylactic rehabilitation phase, but it is recognized
that no type of taping/bracing will prevent all future injuries [23].
Historically, athletes would use ankle taping in an attempt to prevent
ankle sprains. Ankle taping is effective in restricting range of motion, and
decreases the incidence of ankle sprains [24,25]. However, up to 50% of
535CONSERVATIVE MANAGEMENT OF CHRONIC ANKLE INSTABILITY
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the stabilizing effect of ankle taping is lost after as only 10 minutes of exer-
cise [26]. Because of this deterioration of support and the cost of tape, re-
movable and reusable ankle braces were designed as an alternative to
taping. Overall, braces are effective in preventing, decreasing, or slowing
motions that cause lateral ankle ligamentous injuries [27,28], although
braces may not to be as effective as freshly applied tape [27]. However, un-
like tape, braces offer the advantage of being easily adjusted if and when
support becomes compromised. Clinically, braces appear to be at least as ef-
fective as tape in the prevention of lateral ankle sprains [29,30]. One study
showed that in basketball players the rate of ankle injury was triple that
that in nonbraced players [30]. Probably, braces also have a proprioceptive
effect in addition to a purely mechanical one.
Regardless of the type of bracing or taping used, a good rehabilitation
program will contain an individually designed exercise regime to improve lo-
cal muscle strength and endurance. Fully activated and strong peroneal
muscles are probably the best protection for the near maximally inverted
ankle at foot strike [31].
Summary
Chronic ankle instability is a significant cause of morbidity. There are
well-documented and effective surgical options for managing this condition.
However, conservative management can be a viable option in selected pa-
tients. Failure of conservative management can be an indication for surgery
if morbidity warrants it. Surgery can be delayed without necessarily affect-
ing outcome.
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