Current Concepts Review - Rupture of the Achilles Tendon.

19 Pages·1999·0.24 MB·English

This is an enhanced PDF from The Journal of Bone and Joint Surgery

The PDF of the article you requested follows this cover page.
Current Concepts Review - Rupture of the Achilles Tendon

NICOLA MAFFULLI
J Bone Joint Surg Am. 1999;81:1019-36.
This information is current as of November 1, 2010
Reprints and Permissions Click here to order reprints or request permission to use material from this
article, or locate the article citation on jbjs.org and click on the [Reprints and
Permissions] link.
Publisher Information The Journal of Bone and Joint Surgery
20 Pickering Street, Needham, MA 02492-3157
www.jbjs.org
Current Concepts Review
Rupture of the Achilles Tendon*
BY NICOLA MAFFULLI, M.D., M.S., PH.D., F.R.C.S.(ORTH)†, ABERDEEN, SCOTLAND
Achilles, the warrior and hero of Homer’s Iliad, distal margin of the muscle bellies38, whereas the soleus
lends his name to the Achilles tendon, the thickest and tendon begins as a band proximally on the posterior
strongest tendon in the human body138. Thetis, Achilles’s surface of the soleus muscle. The length of the gastroc-
mother, made him invulnerable to physical harm by im- nemius component ranges from eleven to twenty-six
mersing him in the river Styx after learning of a proph- centimeters38 and that of the soleus component, from
ecy that Achilles would die in battle. However, the heel three to eleven centimeters. Distally, the Achilles tendon
by which he was held remained untouched by the water becomes progressively rounded in cross section, to a
and thus Achilles had a vulnerable point. Achilles led level four centimeters proximal to the calcaneus, where
the Greek military forces, which captured and destroyed it can become relatively flatter38, before inserting on the
Troy after killing the Trojan prince Hector. However, superior calcaneal tuberosity191. The fibers of the Achil-
Hector’s brother Paris killed Achilles by firing a poi- les tendon spiral through 90 degrees during its descent,
soned arrow into his heel164. such that the fibers that lie medially in the proximal
Hippocrates, in the first recorded description of portion become posterior distally. In this way, elonga-
an injury to the Achilles tendon, stated that “this ten- tion and elastic recoil within the tendon are possible,
don, if bruised or cut, causes the most acute fevers, in- and stored energy can be released during the appro-
duces choking, deranges the mind and at length brings priate phase of locomotion2. Also, this stored energy
death.”26 Ambroise Paré, in 1575, recommended that a allows the generation of higher shortening velocities
ruptured Achilles tendon be strapped with bandages and greater instantaneous muscle power than could be
dipped in wine and spices, but advised that the result achieved by contraction of the triceps surae alone2.
was dubious27. Operative repair of a ruptured Achilles The calcaneal insertion of the Achilles tendon is highly
tendon was advocated in 1888 by another Frenchman, specialized157,158, as it is composed of the attachment of
Gustave Polaillon27, although an Arabian physician per- the tendon, a layer of hyaline cartilage, and an area of
formed such procedures as early as the tenth century bone not covered by periosteum. A subcutaneous bursa
A.D. In the twelfth century, an Italian surgeon, Gug- may lie between the tendon and the skin to reduce
lielmo di Faliceto, believed that nature was unable to friction between the tendon and the surrounding tissues.
unite divided tendons and that operative treatment was A retrocalcaneal bursa lies between the tendon and the
necessary27. calcaneus191.
Much research has been performed to elucidate the
Structure of the Tendon
etiology of a rupture of the Achilles tendon, but its true
nature still remains unclear190. Also, the best method of Tendons act as transducers of the force produced by
treatment is still fiercely debated. Some physicians ad- muscle contraction to bone. Collagen accounts for 70
vocate operative repair, whereas others insist that an percent of the dry weight of a tendon138. Approximately
operation is unnecessary and poses an unacceptable risk. 95 percent of tendon collagen is type-I collagen, with a
very small amount of elastin10,35. Elastin can undergo as
The Achilles Tendon
much as 200 percent strain before failure153. If it were
The tendinous portions of the gastrocnemius and present in the tendon in high proportions, there would
soleus muscles merge to form the Achilles tendon. The be a decrease in the magnitude of force transmitted to
plantaris muscle, which was present in 93 percent (752) bone150.
of 810 lower extremities in one study38, is medial to the Collagen fibrils are bundled into fascicles containing
Achilles tendon and is distinct from it. The gastrocne- blood and lymphatic vessels as well as nerves154. The
mius tendon originates as a broad aponeurosis at the fascicles are grouped together, surrounded by epitenon,
and form the gross structure of the tendon, which is
further enclosed by paratenon, separated from the epi-
*No benefits in any form have been received or will be received
tenon by a thin layer of fluid to allow tendon movement
from a commercial party related directly or indirectly to the subject
of this article. Funds were received in total or partial support of with reduced friction.
the research or clinical study presented in this article. The funding Although the normal Achilles tendon consists almost
source was Wellcome Trust, London, England.
entirely of type-I collagen, a ruptured Achilles tendon
†Department of Orthopaedic Surgery, University of Aberdeen
Medical School, Polwarth Building, Foresterhill, Aberdeen AB25 also contains a substantial proportion of type-III col-
2ZD, Scotland. E-mail address: [email protected]. lagen35. Fibroblasts from ruptured Achilles tendons pro-
Copyright 1999 by The Journal of Bone and Joint Surgery, Incorporated duce both type-I and type-III collagen on culture187.
VOL. 81-A, NO. 7, JULY 1999 1019
1020 NICOLA MAFFULLI
FIG. 1
Graph showing the stress-strain curve for tendon. Wavy lines indicate the wavy configuration of the tendon at rest, straight unbroken lines
indicate the effect of tensile stresses (at strain levels of less than 4 percent, the tendon can regain its original configuration on removal of the
load), one or two broken lines indicate that the collagen fibers are starting to slide past one another as the intermolecular cross-links fail,
and the set of completely broken lines indicate macroscopic rupture due to the tensile failure of the fibers and the interfibrillar shear
failure. (Modified from: Kannus, P.: Tendon pathology: basic sciences and clinical applications. Sports Exerc. and Injury, 3: 62, 1997. Reprinted
with permission.)
Type-III collagen is less resistant to tensile forces and throughout the Achilles tendon and may vary accord-
may therefore predispose the tendon to spontaneous ing to age, gender, and loading conditions9.
rupture.
Biomechanics of the Tendon
The normal Achilles tendon shows a well organized
cellular arrangement174, in stark contrast to one that is Actin and myosin are present in tenocytes76, and the
ruptured. Tenocytes, which are specialized fibroblasts, tendon itself may have an active contraction-relaxation
appear in transverse sections as stellate cells and are mechanism, which could regulate the transmission of
arranged in rows in longitudinal sections154. This orderly force from muscle to bone54. Fukashiro et al.55 measured
arrangement probably is due to the uniform centrifugal a peak force of 2233 newtons within the human Achilles
secretion of collagen around the column of tenocytes170, tendon in vivo. Komi et al.96 used buckle-type force-
which produce both the fibrillar and the nonfibrillar transducers attached to the ankles of volunteers to
components of the extracellular matrix145 and may also show that, during walking, force builds up within the
reabsorb collagen fibers19,161. tendon before the heel strikes the ground. The force is
then suddenly released for ten to twenty milliseconds
Blood Supply
during early impact. Thereafter, force builds up rela-
Tendons can receive their blood supply from ves- tively fast until it reaches a peak at the end of the
sels originating from three sources: the musculotendi- push-off phase, in a pattern similar to that observed
nous junction, the surrounding connective tissue, and during running. More recently, Arndt et al.5 showed that
the bone-tendon junction132. The blood flow of the Achil- the Achilles tendon can be subjected to nonuniform
les tendon depends on age, with a higher blood flow in stresses through modifications of individual muscle
younger individuals66. The Achilles tendon is poorly vas- contributions. An injury therefore can be produced by
cularized, especially in its midportion92, with blood ves- a discrepancy in individual muscle forces caused, for
sels running from the paratenon into its substance47,161. example, by asynchronous contraction of the various
There is a dispute concerning the distribution of blood components of the triceps surae or by uncoordinated
vessels in the tendon56. Some investigations have shown agonist-antagonist muscle contraction due to impaired
that the density of blood vessels in the middle part of transmission of peripheral sensory stimuli125.
the Achilles tendon is low compared with that in the At rest, a tendon has a wavy configuration, a re-
proximal part101. Others have shown, with use of laser sult of crimping of the collagen fibrils138. Tensile stresses
Doppler flowmetry, that blood flow is evenly distributed cause the loss of this wavy configuration, accounting for
THE JOURNAL OF BONE AND JOINT SURGERY
RUPTURE OF THE ACHILLES TENDON 1021
the toe-region of the stress-strain curve (Fig. 1). As col- as inflammatory and autoimmune conditions46, geneti-
lagen fibers deform, they respond linearly to increasing cally determined collagen abnormalities42, infectious dis-
tendon loads93. If the strain placed on the tendon re- eases7, and neurological conditions126. However, there is
mains at less than 4 percent — that is, within the limits little agreement with regard to its etiology.
of most physiological loads138 — the fibers regain their A disease process may predispose the tendon to
original configuration on removal of the load. At strain spontaneous rupture from minor trauma114. Blood flow
levels between 4 and 8 percent, the collagen fibers start in the tendon decreases with increasing age66, and the
to slide past one another as the intermolecular cross- area of the Achilles tendon that is typically prone to
links fail. At strain levels of greater than 8 percent, rupture is relatively avascular compared with the rest of
macroscopic rupture occurs because of the tensile fail- the tendon100,101,161.
ure of the fibers and interfibrillar shear failure138. Histological evidence of collagen degeneration was
The compliance of the tendon is dependent at least found in all seventy-four ruptured Achilles tendons de-
in part on intratendinous waviness29, which may affect scribed in a study by Arner et al.7. However, nearly
the ability of the gastrocnemius-soleus muscle complex two-thirds of the specimens were obtained more than
to generate force at the extremes of joint motion68. Ul- two days after the rupture. Davidsson and Salo40 re-
timately, it may also influence the forces exerted by ported marked degenerative changes in two patients
muscle contraction on the tendon and, hence, the pro- with a rupture of the Achilles tendon who had an oper-
pensity of the tendon to rupture. ation on the day of the injury. The changes, therefore,
should be regarded as having developed before the
Epidemiology
rupture. In a study by Waterston187, performed at our
Although ruptures of the Achilles tendon are rela- center, all tendons that were operated on within twenty-
tively common, the incidence in the general population is four hours after the injury showed marked degenerative
difficult to determine but has probably increased dur- changes and collagen disruption, in accordance with the
ing the past decade104. Leppilahti et al.105 estimated that findings in another recent study78.
the incidence of ruptures of the Achilles tendon in the Alternating exercise with inactivity could produce
city of Oulu, Finland, in 1994, was approximately eigh- the degenerative changes seen in tendons97. Sports in
teen per 100,000. Most ruptures of the Achilles tendon addition to daily activity places additional stress on the
(range, 44 percent [twelve of twenty-seven]144 to 83 per- Achilles tendon, leading to the accumulation of trauma,
cent [ninety-two of 111]31) occur during sports activities. which, although below the threshold for frank rup-
In the Scandinavian countries, badminton players ap- ture188, could lead to secondary intratendinous degener-
pear to be at particular risk49; in a large study, fifty-eight ative changes53.
(52 percent) of 111 patients who had a rupture of the
Corticosteroids and Rupture of the Tendon
Achilles tendon were playing badminton at the time of
the injury31. A rupture of the Achilles tendon is more Corticosteroids are administered for a variety of
common in males, with a male-to-female ratio ranging diseases and have been widely implicated in tendon
from 1.7:1 to 12:126,146,189, possibly reflecting the greater ruptures. Injection of hydrocortisone into the calca-
prevalence of males than females who are involved in neal tendons of rabbits caused necrosis at the site of
sports, although there may be other as yet unrecognized injection forty-five minutes after the injection, and the
factors. The left Achilles tendon is ruptured more fre- tendons that had been given an injection of corticoste-
quently than the right67,172,173, possibly because of a higher roids showed a delayed healing response compared with
prevalence of individuals who are right-side-dominant those that had received an injection of saline solu-
and thus push off with the left lower limb. Typically, tion11. The anti-inflammatory and analgesic properties
acute ruptures of the Achilles tendon occur in men who of corticosteroids may mask the symptoms of tendon
are in the third or fourth decade of life, work in a white- damage45, inducing individuals to maintain high levels
collar profession, and play a sport occasionally22,67,82. of activity even when the tendon is damaged. Cortico-
The prevalence of rupture of the Achilles tendon steroids interfere with healing, and intratendinous in-
has been shown to be greater in patients who have jection of corticosteroids results in weakening of the
blood group O, at least among Hungarians80 and in some tendon for as many as fourteen days91. The disruption is
Finns99. These findings have not been confirmed in other directly related to collagen necrosis, and restoration of
studies128 even when the same ethnic groups were in- the strength of the tendon is attributable to the forma-
volved105. We were not able to prove an association with tion of an acellular amorphous mass of collagen. For
blood group in our area of Scotland, which has a high these reasons, vigorous activity should be avoided for at
incidence of rupture of the Achilles tendon152. least two weeks after injection of corticosteroids in the
vicinity of a tendon91. Unverferth and Olix183 reported a
Etiology
subcutaneous rupture in five athletes who had been
Spontaneous rupture of the Achilles tendon has given injections of corticosteroids in the region of the
been associated with a multitude of disorders, such Achilles tendon for the treatment of tendinopathy. Re-
VOL. 81-A, NO. 7, JULY 1999
1022 NICOLA MAFFULLI
FIG. 2
Photographs showing the appearance of the feet of an eighty-year-old woman who had bilateral rupture of the Achilles tendon; she had
been managed with orally administered corticosteroids for twenty-eight years because of asthma. The ruptures had been undiagnosed for 7.5
months. At the time of referral, the patient walked with plantigrade feet, with no push-off. She refused any management, as she perceived that
she had adapted well to the functional deficit originating from the ruptures of the tendons. A palpable gap in the substance of the Achilles
tendon was evident bilaterally (arrows).
sidua of the corticosteroids were found at the site of the ology of rupture of the tendon. In France, between
rupture in four of the five patients. A meta-analysis 1985 and 1992, 100 patients who were being managed
recently has shown that corticosteroid injections do not with fluoroquinolones had tendon disorders, which in-
seem to play a beneficial role in the treatment of Achil- cluded thirty-one ruptures156. Many of these patients
les tendinopathy165. also had received corticosteroids, so it is difficult to
Orally administered corticosteroids also have been implicate only the fluoroquinolones. Szarfman et al.176
implicated in the etiology of tendon rupture. At our noted that studies have shown that animals that re-
center, twelve patients who were managed with long- ceived fluoroquinolone in doses close to those admin-
term oral therapy with corticosteroids for the treatment istered to humans had disruption of the extracellular
of chronic obstructive small airways disease were diag- matrix of cartilage, which exhibited as fissuration and
nosed with a rupture of the Achilles tendon during a chondrocyte necrosis, as well as depletion of colla-
ten-year period. Four of them sustained a bilateral in- gen. The abnormalities seen in animals might also oc-
jury136 (Fig. 2). cur in humans. Szarfman et al. recommended that
It still is not possible to pinpoint the etiological the labeling on packaging for fluoroquinolone be up-
role of corticosteroids127, and some studies have not dated to include a warning about the possibility of
demonstrated deleterious effects of these agents. For tendon rupture. In its recommendations on the use of
example, McWhorter et al.115 demonstrated that a sin- this class of antibiotics, the British National Formulary
gle injection of hydrocortisone acetate in a traumatized suggested that “at the first sign of pain or inflamma-
calcaneal tendon of a rat had no important biomechani- tion, patients should discontinue the treatment and rest
cal or histological adverse effect. However, given the the affected limb until the tendon symptoms have re-
present evidence, prolonged oral administration and re- solved.”24
peated peritendinous injection of corticosteroids prob- Recently, Bernard-Beaubois et al.16 found labora-
ably should be avoided. tory evidence of direct deleterious effects of fluoroquin-
olones on tenocytes. They suggested that pefloxacin, a
Fluoroquinolones and Rupture of the Tendon
fluoroquinolone, does not affect transcription of type-I
Fluoroquinolone (4-quinolone) antibiotics such as collagen but decreases the transcription of decorin at a
ciprofloxacin recently have been implicated in the eti- concentration of only 10-4 millimoles. The resulting de-
THE JOURNAL OF BONE AND JOINT SURGERY
RUPTURE OF THE ACHILLES TENDON 1023
crease of decorin may modify the architecture of the played a so-called functional overpronation of the foot
tendon, altering its biomechanical properties, and pro- on heel-strike, with a whipping action of the Achilles
duce increased fragility. tendon. Exaggeration of this whipping action may lead
to intratendinous microtears. Poor flexibility of the
Hyperthermia and Rupture of the Tendon
gastrocnemius-soleus unit was also considered to con-
As much as 10 percent of the elastic energy stored tribute to overpronation33,39. Unequal tensile forces on
in tendons may be released as heat92. Wilson and Good- different parts of the tendon may produce a so-called
ship192 evaluated the temperatures generated in vivo torsional ischemic effect — that is, transient vasocon-
within equine superficial digital flexor tendons dur- striction of the intratendinous vessels — and therefore
ing exercise. A peak temperature of 45 degrees Celsius contribute to the vascular impairment already present
(a temperature at which tenocytes can be damaged4) within the Achilles tendon34.
was measured within the core of the tendon after just Inglis and Sculco75 proposed that malfunction or
seven minutes of trotting. Exercise-induced hyperther- suppression of the proprioceptive component of skele-
mia therefore may contribute to tendon degeneration. tal muscle predisposes athletes to rupture of the Achil-
As good blood supply to tissues should help to cool les tendon. They believed that athletes who resume
overheating, tissues such as the Achilles tendon, which training after a period of rest are particularly susceptible
has relatively avascular areas, may be more susceptible to rupture of the Achilles tendon as a result of this
to the effects of hyperthermia. malfunction.
Knörzer et al.95 used x-ray diffraction spectra to
The Mechanical Theory
study the behavior of the structure of collagen during
McMaster114 proposed that a healthy tendon would tendon-loading. Tendons that rupture without previous
not rupture, even when subjected to severe strain. How- degenerative changes are damaged initially at the sub-
ever, Barfred13-15 demonstrated that, if straight traction microscopic fibrillar level because of a process of in-
were applied to a tendon, as in McMaster’s experi- trafibrillar sliding, which occurs a few seconds before
ments, the risk of rupture would be distributed equally macroscopic slippage of collagen fibers. Therefore, rup-
to all parts of the muscle-tendon-bone complex. If ture of tendons unaffected by degenerative changes
oblique traction were applied, the risk of rupture would may result from the accumulation of fibrillar damage.
be concentrated on the tendon. He calculated that, if a Such findings support the theory that a complete rup-
1.5-centimeter-wide Achilles tendon in a human were ture is the consequence of multiple microruptures and
subjected to traction with 30 degrees of supination on that tendon damage must reach a critical point, after
the calcaneus, the fibers on the convex aspect of the which failure occurs.
tendon would be elongated by 10 percent before the
Mechanism of Rupture
fibers on the concave side would be strained. Therefore,
the risk of rupture would be greatest when the tendon Arner and Lindholm8 classified the trauma resulting
was obliquely loaded, when the muscle was in maxi- in the rupture in ninety-two patients into three main
mum contraction, and when the initial length of the ten- categories. The first category was pushing off with the
don was short. Such factors are probably all present in weight-bearing forefoot while extending the knee. This
movements occurring in many sports that require rapid movement is seen in sprint starts and in jumping in
push-off. Barfred’s theory is largely supported by that sports such as basketball. This mechanism accounted for
of Guillet et al. (reported in a study by Postacchini 53 percent of the ruptures in their series. The second
and Puddu144), who proposed a purely traumatic theory category was sudden, unexpected dorsiflexion of the
for rupture of the tendon in young healthy patients. A ankle, such as that occurring when the foot slips into a
healthy tendon may rupture after a violent muscular hole or the individual falls down stairs. This mechanism
strain in the presence of certain functional and anatom- accounted for 17 percent of the ruptures. The third cat-
ical conditions. These include incomplete synergism of egory was violent dorsiflexion of a plantar flexed foot,
agonist muscle contractions, a discrepancy in the thick- such as may occur after a fall from a height. This mech-
ness quotient between muscle and tendon, and ineffi- anism was reported by 10 percent of their patients. The
cient action of the plantaris muscle acting as a tensor of exact mechanism of injury could not be identified for
the Achilles tendon. the rest of their patients.
Participation in sports plays a major role in the de-
Pathological Characteristics
velopment of problems with the Achilles tendon, and
training errors are a major factor33,39,62,69. The flared heel In 1976, Puddu et al.146 proposed a system to classify
on most sport shoes forces the hindfoot into prona- abnormalities of the tendon. The major categories were
tion when the heel strikes the ground136, and the heel paratendinitis, paratendinitis with tendinosis, and pure
tabs on some shoes may play a similar role. Clement et tendinosis. The term tendinosis describes the degener-
al.34, in a study on the etiology of Achilles tendinopathy, ative processes occurring within the tendon. Tendinosis
found that sixty-one (56 percent) of 109 athletes dis- includes a number of pathological processes, such as
VOL. 81-A, NO. 7, JULY 1999
1024 NICOLA MAFFULLI
hyaline degeneration with a decrease in the normal cell mal collagen48, indicating preexisting denaturation of
population, mucoid degeneration with chondroid meta- collagen.
plasia or fatty degeneration of tenocytes, lipomatous
Presentation and Diagnosis
infiltration of large areas of tendon, an increase in ma-
trix mucopolysaccharides, and fibrillation of collagen Patients who have a rupture of the Achilles tendon
fibers. A rupture of a tendon may be the result of this typically are first seen with a history of sudden pain in
process. In the opinion of Puddu et al., tendinosis is the affected leg, and they often report that, at the time
symptomless and is discovered only on rupture of a of the injury, they thought that they had been struck by
tendon. Patients who have symptoms before the rup- an object or kicked in the posterior aspect of the distal
ture of a tendon commonly have a combination of peri- part of the leg. Some patients report an audible snap.
tendinitis and tendinosis, and it is possible that a They often are unable to bear weight and notice weak-
patient who has tendinosis may become symptomatic ness or stiffness of the affected ankle44. Rupture of the
because of paratendinopathy, which may accompany Achilles tendon may be associated with insufficient
tendinosis. Kannus and Józsa87 noted that only one- warm-up exercises before sports61, with the injury occur-
third of the 891 patients in their study had symptoms ring late in a game. Patients who have a chronically
before rupture of the tendon. We found that only nine ruptured Achilles tendon also tend to have a fairly typ-
(5 percent) of the 176 patients managed because of a ical history; they often recall only very minor or perhaps
rupture of the Achilles tendon at our center between no trauma and that they first noticed the injury because
January 1990 and December 1995 had had previous of an inability to complete everyday tasks such as climb-
symptoms151,187. ing stairs67.
Arner and Lindholm8 reported that all ninety-two Examination may reveal diffuse edema and bruis-
ruptured Achilles tendons that they examined histolog- ing44, and, unless the swelling is severe, a palpable gap
ically had degenerative changes, including edematous may be felt along the course of the tendon44. The site of
disintegration of tendon tissue, patches of mucoid de- the rupture is usually two to six centimeters proximal
generation, and a marked inflammatory reaction. They to the insertion of the tendon44. Krueger-Franke et al.98
also noted that approximately one-quarter of the larger- measured the location of the rupture intraoperatively in
caliber arteries in the peritendinous tissue exhibited 303 patients and ascertained that, on the average, it was
pathological hypertrophy of the tunica media and nar- 4.78 centimeters proximal to the insertion of the tendon
rowing of the lumen. on the calcaneus.
Kannus and Józsa87 noted pathological alterations, In general, rupture of the Achilles tendon does not
97 percent of which were degenerative changes, in all pose diagnostic problems124. However, even in teaching
of the 891 spontaneously ruptured tendons from all of centers, it is not uncommon to find that more than 20
the sites that they studied. The most common degen- percent of such injuries (sixteen of seventy-three in one
erative lesion was hypoxic degeneration, with altera- study74) are missed by the first doctor to examine the
tions in the size and shape of mitochondria, abnormal patient. There are a number of diagnostic signs and tests,
tenocyte nuclei, and occasional intracytoplasmic or both clinical and radiographic, that the examiner may
mitochondrial calcium deposition. In advanced degen- use to aid in diagnosis.
eration, hypoxic or lipid vacuoles and necrosis may be
Clinical Tests
observed. Aberrant collagen fibers also can be seen,
with abnormal variations in the diameter, angulation, Calf-squeeze test: The description of the calf-squeeze
splitting, and disintegration of the fibers. Kannus and test is often credited to Thompson120,122,123, who described
Józsa also noted vascular changes, mostly luminal nar- the test in 1962179,180, five years after Simmonds166. With
rowing due to hypertrophy of the arterial intima and the patient prone on the examining table and the an-
media, in vessels of the tendon and paratenon in 62 kles clear of the table, the examiner squeezes the fleshy
percent of the 891 ruptures. Alterations in blood flow, part of the calf. Squeezing the calf deforms the soleus
subsequent hypoxia, and impaired metabolism may muscle, causing the overlying Achilles tendon to bow
have been factors in the development of the degener- away from the tibia, resulting in plantar flexion of the
ative changes observed in the ruptured tendons87. The ankle if the tendon is intact162. The affected leg should
interval between the rupture and the repair was short always be compared with the contralateral leg166. A false-
enough to suggest that the degenerative changes were positive finding may occur in the presence of an in-
preexisting. tact plantaris tendon, although this has not been proved
Failure of the cellular matrix also may lead to in- scientifically.
tratendinous degeneration103. Józsa et al.82 observed fi- Knee-flexion test: The patient is asked to actively flex
bronectin on the torn surfaces of ruptured Achilles the knees to 90 degrees while lying prone on the exam-
tendons. Fibronectin normally is located in basement ining table. During this movement, if the foot on the
membranes, is present in a soluble form in plasma, and affected side falls into neutral or dorsiflexion, a rupture
binds more readily to denatured collagen than to nor- of the Achilles tendon can be diagnosed130.
THE JOURNAL OF BONE AND JOINT SURGERY
RUPTURE OF THE ACHILLES TENDON 1025
Needle test: A hypodermic needle is inserted through Ultrasonography: Ultrasonography of the Achilles
the skin of the calf, just medial to the midline and ten tendon with linear probes produces a dynamic and pan-
centimeters proximal to the insertion of the tendon. The oramic image of the tendon37, the appearance of which
needle is inserted until its tip is just within the substance varies with the type of transducer that is used and
of the tendon. The ankle is then alternately placed in the angle of the ultrasound beam with respect to the
plantar flexion and dorsiflexion. If, on dorsiflexion, the tendon117. High-frequency probes of 7.5 to 10.0 mega-
needle points distally, the portion of the tendon distal to hertz provide the best resolution, but they have a short
the needle is presumed to be intact. If the needle points focusing distance51. The Achilles tendon is composed
proximally, there is presumed to be a loss of continuity of longitudinally arranged collagen bundles, which re-
between the needle and the site of the insertion of the flect the ultrasound beam. The probe should be held
tendon139. at right angles to the tendon to ensure that an optimum
Sphygmomanometer test: For this test, a sphygmo- amount of ultrasonic energy is returned to the trans-
manometer cuff is wrapped around the midpart of the ducer37, avoiding the production of artifacts51. Linear-
calf while the patient is lying prone. The cuff is inflated array transducers, therefore, are better suited than
to 100 millimeters of mercury (13.33 kilopascals) with sector-type transducers, which produce excess obliquity
the foot in plantar flexion. The foot is then dorsiflexed. of the ultrasound beam at the edges. It also may be
If the pressure rises to approximately 140 millimeters necessary to use a synthetic gel spacer or stand-off pad,
of mercury (18.66 kilopascals), the musculotendinous which increases the definition of the surface echoes
unit is presumed to be intact. If, however, the pressure and allows a suitable support12. A normal Achilles ten-
remains at around 100 millimeters of mercury (13.33 don appears as a hypoechogenic, ribbon-like image that
kilopascals), then a rupture of the Achilles tendon may is contained within two hyperechogenic bands. Tendon
be diagnosed36. fascicles appear as alternate hypoechogenic and hy-
A recent study of 174 patients managed at our in- perechogenic bands that are separated when the ten-
stitution because of a rupture of the Achilles tendon don is relaxed and are more compact when the tendon
demonstrated little or no difference in the predictive is strained12. Men have slightly thicker tendons than
values among the just described tests125. The diagnosis of women86. Rupture of the Achilles tendon is seen on
complete rupture of the Achilles tendon was certain if ultrasonography scans as an acoustic vacuum with
the results of at least two of these clinical tests were thick, irregular edges10,118. Campani et al.25 conducted
positive125. 170 ultrasonographic examinations for various types
of traumatic injury of the lower limb. The Achilles ten-
Imaging
don had the highest percentage of positive findings (75
Plain radiography: Lateral radiographs of the ankle percent); in comparison, only 38 percent of the findings
have been used to diagnose a rupture of the Achilles in the thigh were positive for a lesion. In a study that
tendon. When the Achilles tendon is ruptured, Kager’s I did with two colleagues, we showed that ultrasonog-
triangle85, the fat-filled triangular space anterior to the raphy is a suitable tool for assessing the structure of
Achilles tendon and between the posterior aspect of the tendon after operative repair119. Ultrasonography
the tibia and the superior aspect of the calcaneus, loses also can be used to study the elastic properties of
its regular configuration. Toygar’s sign181 involves mea- the tendon; this is done by measuring the distance be-
surement of the angle of the posterior skin-surface tween an intratendinous hypoechogenic or hyperecho-
curve seen on plain radiographs, as the ends of the ten- genic point and the calcaneus and by assessing how
don are displaced anteriorly after a complete tear. The this distance changes with different forces exerted by
posterior aspect of Kager’s triangle then approaches the gastrocnemius-soleus complex55.
the anterior aspect, and the triangle decreases or disap- Magnetic resonance imaging: The normal Achilles
pears. An angle of 130 to 150 degrees indicates a rupture tendon is seen as an area of low signal intensity on all
of the Achilles tendon. Arner et al.6 found that deforma- pulse sequences. The tendon is well delineated by the
tion of the contours of the distal segment of the ten- high signal intensity of the fat pad of Kager’s triangle85.
don resulting from loss of tone was the radiographic Any increase in intratendinous signal intensity should
change most likely to be associated with rupture of the be regarded as abnormal43. T1 and T2-weighted im-
Achilles tendon. ages in the axial and sagittal planes should be used to
In general, clinical examination is sufficient for a evaluate suspected ruptures of the Achilles tendon. On
diagnosis of acute rupture of the Achilles tendon. Rup- T1-weighted images, a complete rupture of the Achil-
tures that are more long-standing may be harder to les tendon is identified as a disruption of the signal
diagnose because of associated tissue swelling. Real- within the tendon. On T2-weighted images, the rup-
time high-resolution ultrasonography and magnetic res- ture is demonstrated as a generalized increase in sig-
onance imaging provide an adjunct to clinical diagnosis, nal intensity and the edema and hemorrhage at the
and they are more sensitive and less invasive than soft- site of the rupture is seen as an area of high signal
tissue radiography or xeroradiography122,123. intensity84.
VOL. 81-A, NO. 7, JULY 1999
1026 NICOLA MAFFULLI
complex repairs with use of fascial reinforcement or
tendon grafts169. Artificial tendon implants, with use of
materials such as absorbable polymer-carbon fiber com-
posites141, Marlex mesh (monofilament knitted polypro-
pylene)72,140, and collagen tendon prostheses89, have been
used. End-to-end suturing, which can be performed
with local anesthesia163, has been modified by use of ma-
terials such as Dacron vascular graft, which is passed
through the tendon in a Bunnell-type fashion109. Studies
of dogs have shown that Dacron supports the growth of
fibrous tissue133 and facilitates the approximation of the
ends of the tendon, causing less tension at the repair site
than standard sutures109. However, maturation of colla-
gen may be favorably influenced by cyclical tensional
stimuli131. Therefore, lack of tension on the repair site
may not be advantageous.
FIG. 3
Several authors have opposed operative repair, not-
Photograph showing breakdown of the wound after operative
repair of a rupture of the Achilles tendon. The patient had removed ing that the high rate of complications is the main disad-
the cast against medical advice at four weeks after the operation and vantage26,59,102,137,172,173. Arner and Lindholm8, in a series of
had returned to playing volleyball. At his first jump, the skin broke
eighty-six operative repairs of ruptured Achilles ten-
down.
dons, reported a 24 percent rate of complications, in-
Treatment of Acute Rupture
cluding two instances of deep-vein thrombosis, one of
of the Achilles Tendon
which resulted in pulmonary embolism and death; three
The many techniques and procedures described for wound infections; eleven instances of wound necrosis;
the treatment of an acutely ruptured Achilles tendon can and four repeat ruptures. More recent studies have dem-
be grouped under three headings: open operative, per- onstrated a much lower rate of complications. Soldatis
cutaneous operative, and nonoperative. As there is no et al.167, in a study of twenty-three patients who had
agreed-on protocol, the choice of treatment regimen is operative repair, reported only two complications, both
still based largely on the preference of the surgeon and delayed wound-healing. The explanation for this low
the patient108. Nonoperative treatment has its support- rate of complications may be greater operative experi-
ers, but operative treatment has been the method of ence combined with improved technique. However,
choice in the last two decades for athletes and young wound problems should not be unexpected when open
people and for patients who have a rupture for which repair is used, as the most commonly used longitudinal
treatment has been delayed. Acute ruptures in nonath- incision passes through poorly vascularized skin63 (Fig.
letes may be treated nonoperatively. For example, in a 3). In a study of forty patients, Aldam1 used a transverse
prospective, randomized trial, forty patients who had an incision just distal to the gap in the tendon and reported
acute complete rupture of the Achilles tendon were al- only one wound breakdown.
located either to immobilization in a cast for eight weeks Several authors have proposed primary augmenta-
or to immobilization in a cast for three weeks followed tion of the repair177 with the plantaris tendon112,148, the
by controlled early mobilization in a Sheffield splint, peroneus tendon142, a single central gastrocnemius fas-
which is an ankle-foot orthosis that holds the ankle in cial turndown flap21, or two such flaps (one medial and
15 degrees of plantar flexion but allows some movement one lateral)110. However, there is no evidence that pri-
at the metatarsophalangeal joints159. The splint allows mary augmentation of a repair of an acute rupture of
controlled motion of the ankle during physiotherapy. the Achilles tendon is any better than nonaugmented
Patients managed with the splint regained mobility no- end-to-end repair79. I prefer to use augmentation in de-
tably faster and preferred the splint to the plaster cast. layed repairs and in the treatment of repeat ruptures.
The range of dorsiflexion of the ankle improved more After the operation, the leg is immobilized in a cast
rapidly after treatment with the splint, and patients were for four to six weeks31,175. Some surgeons have advocated
able to return to normal activities sooner. Recovery the use of a functional orthosis after several days of
of plantar flexion power was similar in the two groups, immobilization in a cast. This orthosis allows plantar
and no patient had excessive lengthening of the tendon. flexion but restricts dorsiflexion and is designed to help
One repeat rupture occurred in each group159. to prevent atrophy of the triceps surae28,160. Some sur-
geons allow free motion of the ankle but no weight-
Open Operative Repair
bearing after operative repair134,168.
The many operative techniques used to repair rup- There is a never-ending controversy regarding the
tured Achilles tendons range from simple end-to-end use of open operative techniques to manage subcutane-
suturing, with Bunnell or Kessler-type sutures, to more ous ruptures of the Achilles tendon, with some investi-
THE JOURNAL OF BONE AND JOINT SURGERY
RUPTURE OF THE ACHILLES TENDON 1027
gators reporting a high overall rate of complications20,58,77 repair3,23. Also, disturbingly high rates of transfixion of
and others noting few complications30,60,71 and a low rate the sural nerve have been reported70,155,171, with persis-
of repeat rupture17,41,75. tent paresthesias and the necessity of a formal operative
exploration to remove the suture and free the nerve50,94.
Percutaneous Repair
Nonoperative Treatment
Ma and Griffith116 developed a method for percuta-
neous repair as a compromise between open operative The most commonly used form of nonoperative treat-
methods and nonoperative treatment. The technique in- ment is immobilization in a plaster cast, usually for a
volves producing six small stab incisions along the medial period of six to eight weeks31. Immobilization has been
and lateral borders of the tendon and then passing a advocated by those who think that it produces re-
suture through the tendon with use of these incisions. In sults similar to those achieved with operative treat-
a small series of eighteen patients managed with this ment26,59,102,137,172,173. When the Achilles tendon ruptures, the
technique, Ma and Griffith reported only two minor, paratenon generally remains intact172. Stripping of the
noninfectious skin complications and no repeat ruptures. paratenon during an operation reduces the amount of
Rowley and Scotland155 described twenty-four patients reactive tissue that is produced later at the site of the
at our center who had a rupture of the Achilles ten- injury172. Those authors have therefore suggested that
don; fourteen were managed with immobilization in a operative repair of a ruptured Achilles tendon should
cast alone, with the ankle in the equinus position, and be avoided, as the paratenon provides a valuable blood
ten were managed with percutaneous repair. One pa- supply to the damaged tendon. Lea and Smith102, in a
tient who had percutaneous repair had entrapment of study of fifty-five spontaneously ruptured Achilles ten-
the sural nerve, but no other complications were en- dons treated with eight weeks of immobilization in a
countered. The patients who were managed with su- plaster cast, reported that seven (13 percent) of the
tures were more likely to regain nearly normal plantar patients had a repeat rupture and only three patients
flexion strength, and they also returned to activity were dissatisfied with the result. These results contrast
sooner than the group managed with a cast alone. Other sharply with those of Persson and Wredmark143, who
authors have reported a much lower success rate with reported on twenty patients who were managed non-
this technique. Klein et al.94 reported sural nerve entrap- operatively. Seven patients had a repeat rupture, and
ment in 13 percent of thirty-eight patients. Hockenbury seven patients — not necessarily those who had a re-
and Johns70 compared in vitro percutaneous repair of peat rupture — were not satisfied with the result. Al-
the Achilles tendon and open repair of the Achilles ten- though function after nonoperative repair is generally
don with use of a transverse tenotomy of the Achilles good, the high prevalence of repeat rupture is consid-
tendon in ten fresh-frozen below-the-knee specimens ered unacceptable. A primary goal of the treatment of
from cadavera. The specimens were divided into two a rupture of the Achilles tendon is to avoid lengthen-
groups of five specimens each; one group had open repair ing of the tendon, and this cannot be achieved with
of the Achilles tendon with use of the Bunnell suture nonoperative treatment169.
technique, and the other had percutaneous repair with Recently, on the basis of results reported with use
use of the technique of Ma and Griffith116. The tendons of functional postoperative bracing28, McComis et al.113
that were repaired with an open technique were able to managed fifteen patients nonoperatively with a func-
resist almost twice the amount of ankle dorsiflexion tional bracing protocol to repair a rupture of the Achilles
before a ten-millimeter gap appeared in the repaired tendon. They achieved good functional results, proving
tendon compared with those that were repaired with a that, for selected patients, nonoperative functional brac-
percutaneous technique (a mean of 27.6 degrees com- ing may be a viable alternative to operative intervention
pared with a mean of 14.4 degrees; p < 0.05). Entrap- or to use of a plaster cast for the treatment of an acute
ment of the sural nerve occurred in three of the five rupture of the Achilles tendon.
specimens that had percutaneous repair. The tendon Some patients, especially those who are elderly, may
stumps sutured with use of the percutaneous technique be seen with a long-standing rupture that has been dis-
were malaligned in four of the five specimens. On the covered by chance. These patients often adapt well to
basis of the findings in that study, it appears that percuta- the disability, but they are warned that an operation may
neous repair of a ruptured Achilles tendon provides ap- be necessary if the symptoms caused by the rupture of
proximately 50 percent of the initial strength afforded by the Achilles tendon worsen. Such patients are followed
open repair and places the sural nerve at risk for injury. at regular intervals, but they usually do not need addi-
Percutaneously repaired Achilles tendons are less tional treatment125.
thick than are those repaired with open procedures, and
Physiological Effects of Immobilization
some patients may prefer the better appearance that
After a Rupture of the Achilles Tendon
this may afford23. Overall, most studies have demon-
strated that the rate of repeat rupture after percuta- The cross-sectional area of a muscle is directly re-
neous repair is higher than that after open operative lated to the muscle force that the muscle can develop64,73,
VOL. 81-A, NO. 7, JULY 1999