PHYSICAL EXAMINATION 2022, Dec, 22 | 12:00 am

ANKLE AND FOOT EXAMINATION SPECIAL TESTS

CHAPTER

ANKLE AND FOOT ‌

●A LIGAMENT STRESS TESTS

236

Anterior talofibular ligament stress test 236

Calcaneofibular ligament stress test 238

Calcaneocuboid ligament stress test 240

Medial collateral ligament stress test 242

●B LIGAMENT INSTABILITY TESTS

244

External rotation stress test 244

Talar tilt test 248

Drawer test 250

●C OTHER TESTS

255

Thompson’s test 255

Peroneal subluxation test 257

Metatarsal squeeze test 259

235

●A LIGAMENT STRESS TESTS

Anterior talofibular ligament stress test

Purpose

To stress the anterior talofibular ligament (ATFL) in order to detect a grade I/II sprain.

Technique

Patient position

Long sitting on the couch.

Clinician position

One hand cups the calcaneum (right ankle/right hand and vice versa), the other hand is wrapped around the dorsum of the foot, ensuring that the medial border of the hand is positioned over the talus in order to localize stress on the ligament effectively.

Action

The calcaneum is tilted into a plantarflexed position. The upper hand then gradually adds further plantarflexion and inversion (see Fig 7.1).

Positive test

Pain over the lateral aspect of the ankle and/or limited range. Assuming that the ligament is intact, the extent of pain and limitation depends on the acuteness of the injury and its severity.

Clinical context

The ATFL is the most important lateral stabilizer of the ankle and the most frequently injured (Tohyama et al 1995, Trojian & McKeag 1998, Wolfe et al 2001). With the foot in a neutral position, the fibula–ATFL angle is around 90° (i.e. the ligament runs approximately parallel to the sole of the foot) but plantarflexion brings it increasingly parallel to the long axis of the fibula where it functions as the main collateral ligament (Bahr et al 1997). In increasing degrees of plantarflexion and inversion, strain of the ATFL increases, more so than the calcaneofibular ligament (CFL), thereby rendering the ATFL most vulnerable in this position (Bahr et al 1997, Colville et al 1990). The posterior talofibular ligament is the strongest of the

Fig. 7.1 ● Anterior talofibular ligament stress test.

lateral complex and is only injured in a severe inversion sprain (Wolfe et al 2001).

While careful physical examination has been shown to be a valuable tool in the detection of ankle fracture (see clinical tip; Stiell et al 1994), accurate evaluation of ligament injury is more difficult (Fujii et al 2000, Van Dijk et al 1996). Isolated tears do not tend to produce significant instability and pain is usually the dominant finding on stress testing. If the trauma is more severe and accompanied by swelling and bruising, instability testing should be performed (i.e. drawer test, p. 250, and talar tilt test, p. 248) with the index of suspicion high of a double rupture of the ATFL and the CFL, if positive (Bahr et al 1997).

Clinical tip

Leaving the pain and swelling to settle for a few days has been shown to be advantageous in improving the diagnostic accuracy of ligament injury at the ankle (Van Dijk et al 1996).

The widely accepted Ottowa rules for radiographic examination post ankle trauma have been found to produce a very low rate of false negatives and a sensitivity of 100%, reducing the number of ankle X-rays by about 35% (Stiell et al 1992). A subsequent larger

trial confirmed these findings (Stiell et al 1994) which led to effective implementation at multiple centres (Stiell et al 1995). The Ottowa rules (Duckworth et al 2009) state that:

An ankle X-ray is only required if there is:

bony tenderness over the distal 6 cm of the posterior edge or tip of the lateral and/or medial malleolus
an inability to weight-bear immediately following trauma or/ and an inability to walk four steps when examined.

A foot X-ray is required if there is:

pain in the mid-foot zone
bony tenderness at the base of the navicular or fifth metatarsal
an inability to weight-bear immediately following trauma or/ and an inability to walk four steps when examined.

EXPERT OPINION

COMMENTS

★★★

ATFL stress test

An extremely useful test to preferentially stress the ATFL but more valuable once the acute stage has passed and sufficient plantarflexion is available. This can also be

used as a global lateral ligament stress test.

Calcaneofibular ligament stress test

Aka

Inversion stress test

Purpose

To stress the calcaneofibular ligament (CFL) in order to detect a grade I/II sprain.

Technique

Patient position

Long sitting on the couch.

Clinician position

The calcaneum is cupped by one hand (right foot/left hand and vice versa) while the other hand wraps over the dorsum of the foot,

the fingers positioned over the lateral talar dome and the thumb supporting the sole of the foot.

Action

The foot is taken into plantargrade – the talus should not be in the close-packed position. The hand cupping the calcaneum provides a firm varus stress and the range of talar motion can be assessed by palpation.

Positive test

Pain over the lateral aspect of the ankle and/or limited range with no laxity is suggestive of a grade I/II sprain. The extent of pain and limitation depends on the acuteness of the injury and its severity.

Fig. 7.2 ● Calcaneofibular ligament stress test.

Clinical context

This test is exactly the same as the manoeuvre described at the talar tilt test but with the emphasis on the detection of minor ligamentous injury rather than ankle instability (see talar tilt, p. 248). With the foot in the neutral position, the CFL forms a posterior angle of about 130° with the fibula, but with the foot in dorsiflexion the

ligament becomes parallel to the axis of the fibula, thereby functioning as a collateral ligament. As a result, the ligament is under most stress in dorsiflexion and inversion while its lateral companion, the anterior talofibular ligament (ATFL), provides little restraint in this position (Bahr et al 1997, Colville et al 1990). With the reverse occurring in plantarflexion and inversion, it is clear that the ATFL and CFL function together in all positions of ankle flexion to provide lateral ankle stability (Colville et al 1990).

Calcaneocuboid ligament stress test

Purpose

To stress the calcaneocuboid ligament (CCL) in order to detect a grade I/II sprain.

Technique

Patient position

Long sitting on the couch.

Clinician position

Action

The calcaneum is fixed in a neutral position while the other hand applies a combined movement of adduction and inversion of the forefoot (see Fig. 7.3).

Positive test

Pain over the lower, lateral aspect of the ankle and/or limited range, the extent of which depends on the acuteness of the injury and its severity.

Clinical context

The CCL is composed of the dorsal CCL ligament (a thickening of the fibrous capsule on the dorsal surface of the joint) and the CCL component of the bifurcate ligament (Standring 2005). Compared to the prevalence of anterior talofibular ligament (ATFL) injury,

Fig. 7.3 ● Calcaneocuboid ligament stress test.

the CCL is much less commonly involved in ankle sprains. It can either be injured in isolation, where the forefoot is exposed to forced inversion and adduction while the calcaneus is relatively fixed and stable, or as a combined lesion resulting from gross lateral strain. In ankle sprains, the ATFL, calcaneofibular ligament and the CCL can all be involved and the ligaments should always be tested for pain and laxity (i.e. ATFL stress test, p. 236; drawer test, p. 250; talar tilt test, p. 248). If the CCL is involved as part of a combined sprain, the ATFL is most likely to be its injured partner.

Clinical tip

The calcaneum must be held in neutral or slight eversion to keep stress off the ATFL and CFL and ensure most of the stress falls on the CCL.

The calcaneocuboid joint line can be found by placing the side of the thumb up against the base of the fifth metatarsal where the joint will be approximately in line with the midpoint of the thumb pad. It is important to ensure that the hand is positioned just distal to the joint line in order to localize stress on the ligament effectively.

EXPERT OPINION

COMMENTS

★★

CCL stress test

The CCL is often missed as a component of a lateral complex sprain and this test permits more specific localisation.

Medial collateral ligament stress test

Purpose

To stress the medial collateral (deltoid) ligament in order to detect a grade I/II sprain and/or laxity.

Technique

Patient position

Long sitting on the couch.

Clinician position

One hand cups the calcaneum (right ankle/left hand and vice versa). The other hand is wrapped around the dorsum of the foot from the medial side, ensuring that the hand is positioned quite proximally (the medial edge of the hand resting over the navicular) in order to avoid stress falling primarily on the forefoot.

Action

The calcaneum is tilted into a valgus position while the upper hand gradually adds eversion in a degree of dorsiflexion (see Fig. 7.4).

Positive test

Pain over the medial aspect of the ankle and/or laxity is elicited as the stress is added. Mild or chronic cases may report minor discomfort at the end of the movement.

Clinical context

The medial ligament is a very strong fan-shaped structure (composed of the tibionavicular, tibiocalcaneal, anterior and posterior tibiotalar ligaments) which limits eversion of the ankle and lateral displacement of the talus. It is made up of superficial bands which are mainly vertically orientated, limiting rear foot eversion, and deeper fibres, more transverse in direction, which limit abduction/ external rotation of the talus (Placzek & Boyce 2006). Its strength is demonstrated by the fact that the malleolus often fractures before

Fig. 7.4 ● Medial collateral ligament stress test.

the ligament ruptures – 75% of ankle fractures occur on the medial side. Conversely, medial ligament injury represents only 10% of ankle sprains (Trojian & McKeag 1998) and this is attributed to the enhanced medial stability afforded by the mortise of the ankle, the articulation between the medial malleolus and talus and the anterior tibiofibular ligament, all of which make injury much less likely than on the lateral side (Wolfe et al 2001).

Injury to the medial ligament will be evident by the mechanism of injury (excessive eversion with the foot in a neutral or slightly dorsiflexed position), local tenderness, swelling and a positive medial ligament test. If significant trauma has occurred other injuries should also be considered such as a syndesmosis injury (see external rotation stress test, p. 244) or fracture, i.e. Maisonneuve fracture (proximal fibula), distal fibular fracture or avulsion fracture of the medial malleolus (Trojian & McKeag 1998) requiring further evaluation (see Ottowa rules, p. 238) and possible surgical intervention.

Clinical tip

The medial ligament is also vulnerable to chronic strain resulting from poor foot biomechanics. A valgus rear foot and associated

pronation of the forefoot will produce medial forces that, if left uncorrected, may lead to chronic strain on both the medial and spring ligaments. The stress test may well reveal some discomfort at the extreme of the movement and, if very established, a small degree of laxity may be evident. Because this is usually a bilateral problem, making a comparison with the ‘normal’ side is not always possible.

EXPERT OPINION

COMMENTS

★★

MCL stress test

Primarily evaluates the superficial fibres, which are more commonly involved in biomechanical overloading and minor injury.

●B LIGAMENT INSTABILITY TESTS

External rotation stress test

Aka

Kleiger’s test

Purpose

To assess the integrity of the inferior tibiofibular syndesmosis.

Technique

Patient position

Sitting on the side of the couch with the knees flexed to 90°.

Clinician position

The examiner grasps the heel (right ankle/right hand and vice versa) and rests the anterior aspect of the forearm against the medial border of the foot. The foot is positioned in plantargrade. The other hand stabilizes the lower thigh.

Action

A passive external rotation stress is applied to the ankle.

Positive test

The test is positive for a syndesmosis injury if pain is reproduced over the inferior tibiofibular joint.

Fig. 7.5 ● External rotation stress test.

Clinical context

The syndesmosis is stabilized by the interosseous membrane and the anterior and posterior inferior tibiofibular, transverse tibiofibular and interosseous ligaments. Syndesmosis injuries (commonly known as ‘high ankle sprains’) account for about 10% of ankle sprains and are most prevalent in contact sports. This injury, in contrast to lateral ligament sprain, does not present with significant swelling, nor is recurrence common (Trojian & McKeag 1998), although the degree of disability that can follow injury requires careful evaluation and a different management strategy (Wolfe et al 2001).

Syndesmotic injuries of the ankle without fractures can result from external rotation, eversion and dorsiflexion injuries (Wolfe et al 2001). A cadaveric study showed that forced external rotation of the ankle resulted in significant disruption to the inferior tibiofibular joint (Beumer et al 2006). When dorsiflexion is added the anterior tibiofibular ligament is under greatest duress and is most likely to rupture in this position, leaving the mortise of the ankle significantly undermined and mechanically unstable (Beumer et al 2006,

Colville et al 1990). The stress on the posterior tibiofibular ligament in this position is less and, because it is also mechanically stronger, is least likely to rupture (Colville et al 1990). It takes forceful ‘hyper-dorsiflexion’ to expose this ligament to the possibility of significant injury. Combined rupture of both anterior and posterior tibiofibular ligaments, particularly when the anterior band of the deltoid ligament is also involved, creates gross instability (Beumer et al 2006).

This is not a definitive test and should always be used in combination with other findings to establish the extent of the injury. Where instability is suspected MRI investigation provides a more conclusive assessment (Gaebler et al 1997). In the event of the lateral ligaments being intact, the talar tilt test can be used to assess the integrity of the syndesmosis (see talar tilt test, p. 248).

Clinical tip

Failure of the inferior tibiofibular ligaments can result in either substance rupture of the ligament (the dominant failure mode of the anterior tibiofibular ligament) or fibular avulsion (the failure mode for 50% of posterior tibiofibular ligament injuries). As rupture of the anterior tibiofibular ligament is mechanically more likely (see clinical context), the presence of an avulsion fracture should alert the clinician to the possibility of a double ligament injury as well (Beumer et al 2003).

If medial ankle pain is elicited during this test or excess anterior or anteromedial movement of the talus is detected, closer evaluation of the medial ligament should be undertaken.

Injury to the syndesmosis resulting in only a 1 mm lateral shift of the talus due to loss of mortise stability decreases the weight-bear-ing surface of the talus by 40%, a 3 mm shift by 60%, and a 5 mm shift by 80%, thereby generating an increase in contact pressures and accelerating degenerative changes (Placzek & Boyce 2006).

Variations

The Cotton test/side-to-side test/Chalke test positions the patient in the same way but uses both internal and external tibial rotation to stress the mortise.

Related tests

With the patient in long sitting, the dorsiflexion manoeuvre requires tension to be taken off the gastrocnemius and soleus complex by flexing the knee. The lower leg is stabilized with one hand over the lower leg and the calcaneum is grasped with the other, allowing the anterior aspect of the forearm to be positioned under the sole of the patient’s

foot. The ankle is then passively dorsiflexed to end-range. If this is pain-free and no apprehension is detected, the manoeuvre is repeated more forcibly, looking to reproduce pain and/or apprehension (Magee 2008). The dorsiflexion compression test is done in standing. The patient is asked to actively dorsiflex the ankle and report any pain while the examiner assesses the joint range. The test is then repeated with the examiner using both hands to squeeze the malleoli together (Fig. 7.6). The test is considered positive if the pain is reduced and/

or dorsiflexion increased when the squeeze is added (Magee 2008).

Fig. 7.6 ● Dorsiflexion compression test in standing.

Other non-specific tests that can be used for injury to the syndesmosis include: the crossed leg test (Magee 2008) where pain around the syndesmosis is provoked when the patient crosses the affected leg so that the lower third of the fibula rests just above the opposite knee; the heel thump test (Magee 2008) where, with the patient in a sitting position, the examiner uses the fist to hit the centre of the heel while the other hand stabilizes the lower leg and the squeeze test (Wolfe et al 2001) where compression of both the tibia and fibula in the mid-calf region is considered positive if pain over the syndesmosis is elicited.

Talar tilt test

Purpose

The talar tilt test serves two main functions:

to test the integrity of the calcaneofibular ligament (CFL) and the anterior talofibular ligament (ATFL)
to assess the integrity of the inferior tibiofibular syndesmosis.

Technique

Patient position

Long sitting on the couch.

Clinician position

The calcaneum is cupped by one hand (right foot/left hand and vice versa) while the other hand wraps over the dorsum of the foot, the fingers positioned over the lateral talar dome and the thumb supporting the sole of the foot.

Action

The foot is taken into dorsiflexion, short of the close-packed position. The hand cupping the calcaneum provides a firm varus stress and the range of talar motion can be assessed by the other hand positioned over the talar dome (see Fig. 7.7).

Positive test

For CFL/ATFL laxity: increased excursion of the talus is suggestive of a combined rupture of the CFL and ATFL (see clinical context).
For syndesmosis injury: reproduction of high ankle pain, increased movement of the talus, apprehension and a painful clunk as the talus rotates in the widened mortise would all be indicative of syndesmosis disruption.

Clinical context

Injury to the CFL rarely occurs in isolation but it is vulnerable to inversion trauma and, if injured, will invariably be partnered by a torn ATFL. The ATFL takes the strain as the ankle moves into greater degrees of plantarflexion and inversion, while the CFL is most stressed when the talus is dorsiflexed and inverted (Bahr et al 1997). Essentially these two ligaments function together in all positions of ankle flexion to provide lateral stability (Colville et al 1990).

Fig. 7.7 ● Talar tilt test.

With both ligaments torn, significant anterolateral instability ensues and both this test and the drawer test (see p. 250) are likely to be positive (Bahr et al 1997).

In an attempt to analyse the significance of varying degrees of increased talar movement, results of the test were compared with MRI investigation and findings at surgery (Gaebler et al 1997) as follows:
- ,5° talar tilt: half were found to have no ligament damage and the rest had either single ATFL injury or a combined ATFL/CFL tear.
- 5–15° talar tilt: a third had the combined ATFL/CFL rupture and an incomplete rupture of the posterior talofibular ligament; the rest had either double or single ruptures.
- .25° talar tilt: all had complete combined ATFL/CFL ruptures with either complete or partial ruptures of the posterior talofibular ligament reported.

While clinically useful to detect injury and laxity, the talar tilt test cannot therefore be regarded as an accurate tool for evaluating the exact extent of lateral ankle ligament injuries (Gaebler et al 1997, Van Dijk et al 1996, Wolfe et al 2001).

Involvement of the syndesmosis in ankle injury usually results from catastrophic ligamentous disruption (and fracture) but forced dorsiflexion/external rotation may cause an isolated injury (see external rotation stress test, p. 244). Disruption of the tibiofibular joint can lead to diastasis, rendering the mortise inherently unstable. The varus movement of the calcaneum during the talar tilt test, tensions the CFL (and ATFL) which in turn challenges the syndesmosis by pulling on the fibula and potentially widening the mortise enabling the talus to rotate excessively. It is essential, therefore, that the ATFL and CFL are intact if the test is being used for this purpose.

Clinical tip

A talar tilt of around 15° or more usually indicates a complete rupture of the ATFL and CFL (Gaebler et al 1997). The use of MRI has been advocated in cases where the talar tilt is between 5° and 20° (a lower threshold for imaging is recommended in the younger athlete) to determine the extent of injury before deciding on an appropriate management strategy (Gaebler et al 1997).

Drawer test

Aka

Positive ‘suction’ or ‘dimple’ sign

Purpose

To test the integrity of the anterior talofibular ligament (ATFL).

Technique

Patient position

The patient lies supine with the knee flexed and the foot resting on the couch.

Clinician position

Standing on the opposite side of the couch to the leg being tested. The webspace of the caudal hand is placed over the talus in order to provide stabilization during the test; the other hand is wrapped over the distal tibia and fibula so that the fingers are placed laterally and the thumb is over the medial malleolus, ensuring a clear view of the distal fibula is possible.

Action

Downward pressure is applied to fix the talus while the fibula and tibia are pushed backwards, observing the degree of posterior movement of the lateral malleolus.

Positive test

Increased posterior movement of the lateral malleolus is a positive sign and indicates laxity or rupture of the ATFL. This backward movement of the malleolus can result in a negative pressure which sometimes draws the adjacent skin in, producing the dimple or suction sign.

Fig. 7.8 ● Drawer test.

The arrow indicates the direction of tibial movement.

Clinical context

The most common mechanism of injury is a combination of plantarflexion and inversion where the ATFL and calcaneofibular ligaments (CFL) are particularly vulnerable. As the primary ligamentous restraint to forward subluxation of the talus, the ATFL is by far the most easily injured and rupture can result in a degree of instability, although concomitant injury to the CFL will amplify this significantly (see talar tilt test, p. 248) (Bahr et al 1997). The posterior talofibular ligament is the strongest of the lateral complex and is rarely injured in an inversion sprain (Wolfe et al 2001).

The drawer test is used to assess the integrity of the ATFL. In the event of a grade I sprain where no laxity is present, the ATFL stress test (p. 236) should be used to confirm injury.

The ATFL has been shown to be under greatest tension in 10–20° of plantarflexion (Bahr et al 1997, Colville et al 1990, Tohyama et al 1995) which, combined with 90° knee flexion, reduces soft tissue tension and largely removes the secondary restraint afforded by the gastrocnemius/Achilles complex (Kovaleski et al 2008), providing the ideal position to apply the test. The preferred choice by many clinicians, this version of the technique exposes stress on the ligament in the optimum position and reverses the conventional point of fixation where the tibia and fibula are fixed and the talus is drawn forwards – i.e. anterior drawer of the talus.

In the event of a combined ATFL and CFL rupture, the medial ligament acts as the centre of rotation during movement, allowing the talus to rotate internally – having lost its lateral restraints. Emphasizing the backward pressure over the fibula to deliver a slight rotational force may well improve the sensitivity of the test (Bahr et al 1997). Alternatively, if the ‘original’ test is performed, the foot should be pulled forwards and medially (Van Dijk 1996).

Both the sensitivity and specificity of the anterior drawer test have been called into question (Bahr et al 1997, Becker et al 1993, Lähde et al 1988), particularly when performed in the first day or two after injury (Van Dijk et al 1996). When the physical examination is performed by an experienced clinician at 5 days post trauma, the combination of a haematoma, pain on palpation and a positive anterior drawer test showed a high level of sensitivity and specificity for an ATFL tear compared to testing in the first 48 hours (Van Dijk et al 1996). The usefulness of further investigations and the attendant cost implications have therefore been questioned (Van Dijk et al 1996), although

TABLE 7.1 DRAWER TEST
Author and year	LR+	LR—	Target condition
Van Dijk et al 1996	6 ★★	0.05 ★★★	ATFL laxity 5 days post injury (physical examination including drawer test)
Van Dijk et al 1996	1.05	0.88	ATFL laxity ,48 hours post injury (physical examination including drawer test)

in cases where physical examination has been unable to differentiate between isolated and combined tears, both MRI and arthrography are regarded as valuable methods of diagnosis (Gaebler et al 1997).

Clinical tip

Performing this test successfully requires the clinician to ensure that the patient is relaxed and that the force is applied gradually. A large amount of force is not necessary to achieve posterior translation of the lateral malleolus; indeed, lower forces have been shown to be more effective, as higher forces tend to elicit a protective muscle contraction which may mask a positive finding (Tohyama et al 2003).

In addition to lateral ligament damage following an inversion injury, patients sometimes also report medial ankle pain. Severe injury can evoke traumatic capsulitis of the subtalar joint where heel pain is accompanied by a loss of varus movement and a hard ‘end-feel’. MRI evaluation also reveals high rates of bone bruising of the talus, probably explained by the pathomechanism of the inversion injury, where the medial malleolus is ‘rammed’ against the talus. This mechanism induces shear forces that may cause osteochondral lesions of the talar dome, a feature sometimes observed in the more severely injured ankle (Gaebler et al 1997).

EXPERT OPINION

COMMENTS

★★★

Drawer test

This test specifically evaluates the integrity of the ATFL. A double injury involving the CFL does not increase the amount of drawer excursion.

Variations

The original test literally creates an anterior drawer of the talus. The patient lies supine with the knee flexed. Grasping the patient’s heel with one hand, the ankle is held in about 10–20° of plantarflexion, allowing the sole of the foot to lie on the anterior surface of the examiner’s forearm. The other hand fixes the distal end of the tibia in order to prevent anterior movement during the test. The patient must try to consciously relax the lower leg and foot before the test is performed in order to minimize the chance of a false negative finding. The heel is then pulled forward (Fig. 7.9). When a rupture of the AFTL is present, the lateral side of the talus translates forwards, essentially rotating partially out of the ankle mortise. The centre of rotation is created by the intact medial ligament (Magee 2008).

Fig. 7.9 ● Anterior drawer test. The arrow indicates the direction of calcaneal movement.

The anterior drawer test in prone has the patient lying prone with the feet over the edge of the couch. The lower leg is fixed against the couch with one hand while the webspace of the other hand is positioned around the back of the calcaneum and a downward pressure is applied (Fig. 7.10). Excessive anterior movement indicates ligamentous laxity.

Fig. 7.10 ● Prone anterior drawer test. The arrow indicates the direction of calcaneal movement.

●C OTHER TESTS

Thompson’s test

Aka Simmonds’ test Squeeze test

Purpose

To detect the presence of a complete rupture of the Achilles tendon.

Technique

Patient position

The patient is positioned prone with their feet hanging over the edge of the couch.

Clinician position

The palm of the clinician’s hand is positioned over the patient’s calf at the point where the girth is widest, with the thumb on one side and fingers on the other.

Action

The clinician then opposes thumb and fingers to squeeze the calf (see Fig. 7.11).

Positive test

A lack of plantarflexion indicates a complete rupture. In a negative test where the tendon is intact, the ankle involuntarily plantarflexes. An inability to push-off during the normal gait cycle or get anywhere near a heel raise on the affected side would also be suggestive of a complete rupture. The loss of an intact Achilles tendon will be detectable when the ankle is passively dorsiflexed, particularly when the knee is held in extension, where the loss of soft tissue resistance will result in excessive movement and an altered end-feel. Normally a palpable gap in the tendon is also evident (Gross et al 2002).

Clinical context

Thompson’s test is widely considered to be the ‘gold standard’ for detecting Achilles rupture (Placzek & Boyce 2006). The most common site for the injury is around the hypovascular section of the tendon, approximately 3–6 cm proximal to the insertion. Rupture is often seen in the older, deconditioned individual where there

Fig. 7.11 ● Thompson’s test indicating the normal response of plantarflexion when the calf is squeezed.

is a mismatch between demand and the tendon’s ability to cope with forceful loading. The degenerative process reduces the tensile strength of the tendon (Maffuli et al 2005) and that, combined with sporadic and often sudden activity, makes the Achilles a vulnerable structure. It is also sometimes seen in the younger athlete who, having encountered prolonged inactivity resulting from another injury, then exposes the tendon to sudden, unaccustomed loading. The mechanism of injury is invariably rapid plantarflexion during full weight-bearing (i.e. jumping/landing or a sudden lunge during sport such as badminton or tennis). At the time of injury, the patient usually reports a severe, sharp pain around the heel although their lasting memory is of a loud ‘crack’ which feels like they have been hit from behind.

TABLE 7.2 THOMPSON’S TEST

Author and year

LR+

LR—

Target condition

Malanga & Nadler 2005

13.7

★★★

0.04

★★★

Complete rupture

Clinical tip

The test is only positive if the tendon is completely ruptured although some minor discrepancy in foot movement may be noted with a significant partial rupture (Scott & Al Chalabi 1992).

Additional tests

Matles’ test can also be used to detect Achilles rupture. The patient lies prone with their foot over the edge of the couch. The patient is asked to flex the knee of the affected leg to 90 °. The position of the foot is observed through the movement. With a normal Achilles, the foot gently moves into a degree of plantarflexion. If the foot falls into a neutral or slightly dorsiflexed position the test is considered to be positive. The test can also be performed passively in the case of the reluctant or anaesthetised patient. (See Table 7.3.)

TABLE 7.3 MATLES’ TEST

Author and year

LR+

LR—

Target condition

Malanga & Nadler 2005

5.9

★★

0.14

★★

Complete rupture

Copeland’s test has the patient lying prone with the knee flexed to 90°. A sphygmomanometer is positioned around the bulk of the calf and inflated to 100 mmHg with the ankle positioned in plantarflexion. The foot is then passively dorsiflexed. If the tendon is intact a rise in pressure to around 140 mmHg would be expected but only a flicker is elicited in the event of complete rupture. (See Table 7.4.)

TABLE 7.4 COPELAND’S TEST

Author and year

LR+

LR—

Target condition

Malanga & Nadler 2005

9.7

★★

0.24

★

Complete rupture

Peroneal subluxation test

Purpose

To detect subluxation/dislocation of the peroneus brevis and longus tendons as they travel behind the lateral malleolus.

Technique

Patient position

Long sitting on a couch.

Clinician position

The clinician palpates over the peroneal tendons as they pass behind the lateral malleolus.

Action

The patient is asked to actively dorsiflex and evert the affected foot.

Positive test

The clinician will feel the tendon sublux or snap out of position and/or the manoeuvre will elicit pain.

Fig. 7.12 ● Peroneal subluxation test.

Clinical context

The peroneus longus and brevis tendons lie in a shallow groove (retromalleolus sulcus) behind the lateral malleolus of the fibula where they are contained by the bone anteriorly and the retinaculum laterally. Relatively common among skiers, the mechanism of injury is usually a forceful dorsiflexion/eversion movement of the foot combined with a strong reflex contraction of the peroneal muscles (Placzek & Boyce 2006). Fracture of the posterior edge of the fibula can also result in instability of the tendons.

Patients typically report lateral pain behind the malleolus when walking and this may become more pronounced when they walk on their heels (Trojian & McKeag 1998). A history of locking is also often described and if combined with the other findings the diagnosis is almost certain. The tendon most likely to sublux is peroneus brevis and although both tendons can dislocate, the longus never does in isolation. If left untreated, the subluxation can become recurrent and lead to tears of the brevis tendon.

Clinical tip

An acutely subluxed tendon can masquerade as an ankle sprain as the mechanism of injury and site of the pain may appear similar at first. The presence of swelling posterior to the lateral malleolus, pain on both resisted isometric eversion in dorsiflexion and passive ankle plantarflexion/inversion, along with and a ‘snapping’ sensation on movement, is strongly suggestive of peroneal instability (Placzek & Boyce 2006).

In the acute stages particularly, pain may inhibit an adequate peroneal contraction which could lead to a false negative conclusion.

EXPERT OPINION

COMMENTS

★★★

Peroneal subluxation test

As well as the typical mechanism of injury, forced inversion with an associated reflex peroneal contraction can also result in injury to the retinaculum and lead to peroneal instability.

Metatarsal squeeze test

Aka

Morton’s test

Purpose

To detect a Morton’s neuroma on the intermetatarsal plantar digital nerve.

Technique

Patient position

Long sitting on the couch.

Clinician position

The medial and lateral aspects of the forefoot are grasped using one hand.

Action

The medial and lateral aspects are squeezed together with one hand and the area of tenderness palpated with the other.

Positive test

Provocation of the pain.

Fig. 7.13 ● Metatarsal squeeze test with palpation of the tender area between the metatarsal heads on the plantar aspect of the foot.

Clinical context

Neuromas are thought to result from irritation of the intermetatarsal plantar digital nerve as it travels under the metatarsal ligament. Poorly fitting footwear is commonly blamed for the symptoms and the patient reports a deep, localized ‘burning’ pain in the plantar aspect of the forefoot which is sometimes accompanied by localized paraesthesiae extending into the toe. Commonly neuromas are found in the space between the third and fourth metatarsals and are rare between the first and second and the fourth and fifth. Palpation in the webspace over the neuroma is also commonly tender (Placzek & Boyce 2006).

Clinical tip

An audible or palpable click can sometimes be elicited by gliding the two metatarsals in question in a dorsal and plantar direction while applying the compression. This is thought to occur as a

result of the neuroma catching between the metatarsals while under compression and is more likely where the condition is advanced or established. This is known as Mulder’s sign (Gross et al 2002, Malanga & Nadler 2005). Though fascinating for the clinician, the test is uncomfortable for the patient and should not be repeated unnecessarily.

An accessory sign is pain elicited by metatarsophalangeal joint extension which tightens the ligament and increases compression on the nerve (Placzek & Boyce 2006).