Achilles Tendon Injuries in Kendo

Kendo Clinic articles are intended as an educational forum only. The articles presented offer only a limited over-view of the great number of possible ailments and their variations. Articles are based on documented medical practices; use established terminology and are intended to provide the reader with the information needed to engage in consultation with medical professionals. The authors of Kendo Clinic and the editors of Kendo World stress that the information offered in these articles should under no circumstances be used for self-diagnosis or self-treatment. Persons suffering from any injuries or ailments are urged to seek the advice of licensed medical professionals at the earliest opportunity.

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BY ARIMA SABURO MD

TRANSLATED BY M.I. KOMOTO

Kendo practitioners statistically do not suffer as many traumatic injuries as compared to those of some other budo, say judo with its varied injuries to torso and extremities, or aikido with injuries to shoulder and arms. However, an ailment or failure of the Achilles tendon is one of the most traumatic and debilitating conditions that the kendo man or woman can be faced with.

The vulnerability of the Achilles tendon in the warrior is chronicled in Greek mythology. Achilles, the great hero of the Trojan War was, as a youth, immersed in the River Styx by his mother, in order to render him immortal. However, Thetis, holding her young son Achilles by the heel, left that region of the otherwise indomitable warrior susceptible to human travails.  Even to this day, the Tendo Calcaneus is associated with the demise of Achilles, felled on the battlefield by an arrow wound to the heel.

achilles tendonThe anatomy of the lower extremities is quite complex. Articulation of the ankle is related not only to the joint and musculature of the ankle, but to those of the knee, upper leg, and hip. Condition and integrity of the Achilles tendon is affected by posture, degree of exercise, and general health of the kendoist. Factors such as drug use, illnesses, an over-weight condition, and smoking can contribute to a higher potential for injury. In the special case of the kendoist, the biomechanics of improper posture, or execution of techniques may also precipitate injury to the Achilles tendon.

The Achilles tendon, the largest, and strongest of tendons in the body, connects the gastrocnemius and soleus muscles (the calf) of the lower leg to the calcaneus (the bone projecting from the back of the foot.) The Achilles tendon serves as a crucial component in the tendo calcaneus group (lower leg posterior group) to exert plantar flexion (extending the foot down and away.)

The following list of just some of the more common ailments resulting from over-exertion and prolonged over-use obviates the complex nature of low-leg action and the difficulty of making accurate diagnosis:

— Retrocancaneal bursitis (inflammation of tissues associated with the attachment of the tendon to the calcaneus, the projecting bone which forms the heel).

— Achilles tendon bursitis (inflammation in areas of friction between adjacent tissues).

— Peritendinitis (also known as tenosynovitis, inflammation of the tendon sheath), and tendonitis (inflammation of the tendon, or tendon-muscle attachments).

— Partial and complete ruptures of the Achilles tendon.

achilles tendonPlantar flexion is necessary for raising the heel up, and “pushing-off” for forward propulsion. With particular regards to kendo activity, the left leg is subject to very high loads when executing forward-moving techniques such at tobi-komi waza, the explosive lunging techniques made against distant opponents. Additionally, the extremely high loads of braking backwards movements when making abrupt 180-degree direction changes, or receiving an opponent’s tai-atari (body strike), can create over-capacity loads on a distressed tendon. If these movements are not conducted properly, the potential for injury to the Achilles tendon is greatly increased. For example, a tobi-komi waza executed with the foot abducted (toe pointing out), results in lower mechanical advantage of the exertion. Greater force is required to perform the same amount of forward propulsion, and in exerting that greater force, a greater load is tolled upon the tendon. Another common technical deficiency occurs when the heel is allowed to drop from the correct raised position, and is “planted” down on the floor while making abrupt 180-degree direction changes, or when receiving an opponent’s tai-atari. With the heel planted and leg extended in a locked position, the shock-absorber-like action of numerous muscles and joints of the leg working in unison is nullified, resulting in the full load of impact being focused on the Achilles tendon.

kamaeIn the worst scenario, the tendon can partially or completely rupture, resulting in the loss of “pushing” power of the leg. When this type of injury occurs, there is pain and inflammation associated with the injury itself, and often, a coincident, abrupt contraction (severe cramping) proximally (upward), of the gastrocnemius muscle, which adds greatly to the discomfort and duress of the injured.

Failures of the Achilles tendon usually occur 2 to 6 centimeters above the insertion of the tendon in the heel. This is probably due to the lower blood flow, and smaller cross-sectional density of that portion of the tendon. The sufferer usually presents with much reduced or complete inability to ambulate, and great pain in the posterior region of the affected leg, issuing from as high as the knee, through the mid-section of the calf, and down to the heel. The patient will commonly report of an audible “pop” or “snapping” sound, accompanied by a shooting pain. Subsequently, ambulation becomes more difficult, with heel-raising and stair climbing becoming impossible.

Drug related factors that may contribute to tendon failure are the use of corticosteroids, anabolic steroids, and flouroquinolones. Corticosteroids are anti-inflammatory agents that have been shown to cause degeneration of tendon tissue in animal studies. Anabolic steroids are used by some athletes to increase muscle mass and improve performance. In both cases, these drugs may serve to obscure painful symptoms of tendon ailments, and may result in the kendo practitioner over-exerting an already compromised tendon. Flouroquinolones are a type of antibiotic used for serious infection. As a result of the recent terrorist Anthrax biological-agent attacks, many have taken to the use of flouroquinolones, both as counter-agent and prophylactic. While the medical community is warning the general population of the possibility of developing drug-resistant strains of diseases, they are not emphasising another potential side effect of the drug of contributing to tendon rupture. This type of drug is a very valuable weapon in the arsenal against serious infection, but one should exercise discretion concerning its use. It has been shown that both anabolic steroids and flouroquinolones can reduce the tensile strength of tendons.

Smoking is shown to decrease the oxygen levels in the blood stream and to cause vascular constriction. Although there are no direct studies concerning the relationship of smoking to Achilles tendon failure, if we take into consideration other models in which poor blood flow results in lower tensile strength of tendons, we may infer some relationship to the integrity of the Achilles tendon. More research is necessary to determine the exact effect, however.

Disease related factors include, but are not limited to gout, and arteriosclerosis. All conditions that affect pulmonary action, blood circulation, and blood chemistry should be taken into consideration with regards to Achilles tendon integrity.

Although it may not be commonly considered an illness, an over-weight condition, ranging from being mildly chubby to obese, is significant with concern to loads to the Achilles tendon. If a person considers themselves at risk of Achilles tendon ailments due to limited practice time, drug or illness related factors, or smoking, weight control should become a key element of prevention by reducing inertial loads on the tendon.

First aid for Achilles tendon ailments should begin with immobilisation of the foot in a plantar flexed position. The posterior region of the affected leg, from the back of the knee to the heel, should be cooled by the use of ice, commercial first-aid cold-packs, or by a cryo-system (cold water circulation device). Finally, the lower leg should be elevated above heart-level to minimize edema (swelling cause by accumulation of fluid in intercellular spaces). The sufferer should be examined as soon as possible to determine the exact nature and extent of the injury.

Ailments of the Achilles tendon, although not rare, are not an everyday issue for the general medical caregiver. Some studies have shown that 25% of ruptured Achilles tendons are missed on first examination. Perhaps due to the lower blood flow to those affected tissues as mentioned earlier, hemorrhagic discoloration (“black and bluing”), and edema may not appear immediately. This may make the extent of the trauma less conspicuous upon initial inspection. With time, swelling may develop. Conversely, in this case, inflamed tissues may mask the location or severity of the injury. In either circumstance, a caregiver might diagnose only a “strain” or “partial tear” based on the patient’s continued ability to plantar flex his/her ankle. Additionally, the presence of an “end point” during a manipulation examination in which the ankle is manually dorsi flexed (toes pushed up and back toward the shin), may cause the examiner to believe that the Achilles tendon is still intact. This misleading capacity might also be attributed to other, yet intact muscles that assist plantar flexion.

A table of other muscles that assist in plantar flexion:

Plantaris Peroneus brevis

Tibialis posterior Flexor hallucis

Peroneus longus Flexor digitorum longus

In order to isolate the gastronemius and Achilles tendon and thereby make a more direct evaluation as to their integrity, a number of simple tests are available.

Repetitive heel raises should be attempted. A sufferer of a ruptured Achilles tendon will not be able to execute more than a few raises, if at all, exceeding the capacity of the other, auxiliary flexors that may still be intact.

thompson testThe Thompson test should be performed next. This test consists of the patient being placed in a prone (face-down) position on an examination table, or kneeling on a chair, with the foot hanging freely over the edge. The calf muscle is then squeezed about mid-way, or at the “fat” part of the muscle. If plantar flexion occurs, the tendon is still intact. However, if no plantar flexion results, a ruptured Achilles tendon is suggested. In this case the result of the Thompson test is considered “positive.”

Following the Thompson test, the Copeland test should be administered. This test utilises a sphygmomanometer (a blood pressure cuff). The patient is placed in a prone position, with injured leg flexed at the knee to 90 degrees (the lower leg pointing up). The cuff is placed around the mid-calf region. The patient’s foot is articulated to a plantar-flexed position, and the cuff inflated to 100 mm Hg. The ankle is then dorsiflexed, drawing the toes up toward the shin. In a leg with an intact Achilles tendon the pressure increases to about 140 mm; however, in the case of a ruptured tendon the pressure changes only slightly, or may not change at all. In the absence of any significant change in sphygmomanometer reading, the test result is positive for Achilles tendon rupture.

In all physical examinations, the skill and experience of the examiner plays a critical role. Where any question may exist, the same tests can be administered to the healthy contra-lateral leg to provide a comparison.

Following a physical examination, a number of medical imaging systems are available for verifying results of physical examinations, and to gain a more precise understanding of the extent of the injury.

An Ultrasound examination utilises high frequency sound waves that penetrate into the affected region, the echoes of which are registered by a sensor, and in turn, are displayed graphically on a screen. The ultrasound exam is inexpensive and fast; however, the necessity of extensive experience in examining Achilles tendons injuries, and the difficulty in distinguishing partial and full tears limit the usefulness of this method.

CT or CAT Scan (Computer Axial Tomography) utilises an x-ray beam scan, moving back and forth over the injured area. The radiation absorption variations of normal and pathological tissues are registered by axial tomography and are in turn graphically reconstructed by computer. CT Scans provide high contrast and detailed cross-sectional images. In recent times; however, such detailed data can be acquired by another test, without exposing the patient to ionizing radiation.

mriFinally, there is the MRI (Magnetic Resonance Imaging) examination. In this imaging system, a very strong magnetic field is generated around the affected area. The MRI can detect even minute differences in the electromagnetic properties of the tissues and produces graphic images that detail those differences. The MRI provides the clearest differentiation between tendons affected with peritendinitis, tendonitis, partial and complete ruptures, and the extent and location of those pathological tissues. Another attractive aspect of the MRI is the absence of ionizing radiation as compared to the CT Scan. Although cumbersome in terms of both implementation and cost, the added accuracy of the MRI makes this the preferred imaging system for the diagnosis of Achilles ailments.

In cases where test results (for rupture) are negative, the examiner must consider the various soft tissue ailments such as bursitis and tendonitis, or the possibility that there is injury to some other component of the lower leg musculoskeletal structure.

In the case of bursitis or tendonitis, a combination approach should include curbing activity, ranging from reduction to total rest, physical therapy including stretching, massage, and various modalities such as ultrasound, electronic muscle stimulation, and Electric Acupuncture Stimulation. In extreme cases, immobilization by taping or casting, supplemented by the use of crutches may be necessary. When warranted, medication is best in the form of non-steroidal anti-inflammatory drugs. Some may consider the use of direct corticosteroidal injections; however, upon consideration of the afore mentioned possible side effect of tissue degeneration, I refrain from such therapy in my practice, regardless of the short-term anti-inflammatory benefits.

In the case in which partial or full rupture of the Achilles tendon is determined, the patient and physician are faced with the decision of what type of treatment is necessary. Partial and even full ruptures can heal by themselves, without surgical intervention; however, the many factors of the patient’s specific circumstances should be taken into consideration before an approach is selected.

In over-viewing the great base of data and studies concerning treatment of Achilles tendon ruptures, we can find no clear consensus as to the superiority of either conservative or surgical approaches. Indeed, I do not advocate one method over the other, both methods having some advantages; but rather, extent of injury, the elapsed time from injury to treatment, and the requirements of the patient should serve as the determining factors as to which method is most appropriate.

In a non-surgical approach, the ankle is immobilized with a splint or cast. Initially, the foot is set with ankle plantar flexed at 40 to 60 degrees. Care must be taken to verify that the ends of the ruptured tendon are situated in apposition. This can be done quickly and conveniently with ultrasonic examination just prior to immobilization.

Failure to approximate the ruptured ends can result in a weak tendon, either due to failure to regenerate to full thickness, healing in a disorganized fashion, or the development of extensive fibrous tissue, resulting in a tendon that is prone to elongate or re-rupture.  Another potential complication of insufficient plantar flexion at the time of immobilization is a tendon that heals in an elongated condition. In this case, we might say that the tendon is “slack,” or loose. The practical result of this condition being lower “push-off” strength, as compared to a properly tensioned tendon of normal length. Following initial immobilization, casts are changed periodically, with progressive reductions in plantar flexion. Eventually, the foot is rendered in a plantigrade position (axis of the foot at 90 degrees to the tibia, the large bone of the lower leg). In the later stages, the patient is allowed to bear weight with crutches.

Once access to the injured leg is possible, or the patient is allowed any ambulation, supervision and patient education are rendered by PTs (licensed physical therapists) or certified rehabilitation caregivers. While still in crutches, patients progress toward full weight bearing gait. Recently, functional braces that allow controlled movement of the ankle, limiting the degree of plantar/dorsi flexion, with adjustable heel-lift, have become available.  This option is particularly attractive when a fast, aggressive rehabilitation course is necessary.  At the later stages, the immobilization is removed and the patient continues use of crutches.  In accordance with rehabilitation protocols, the patient resumes unassisted walking with heel lifts (pads adhered to, or inserted into the patient’s shoes, raising the heels). The purpose of the lifts being one of reducing loads on a taut tendon. Bilateral (both sides, right and left legs) lifts allow for a more even gait, and less offset loads to hips and lower back. As range-of-motion and patient confidence is restored, the lifts are removed, and the final stages of rehabilitation and return to activity are conducted. Typically, a non-operative course as described above will cover three to 4 months.

Surgical interventions fall into two categories: small incision approach, and open surgery. Open surgery falls into yet another two categories: repair, and reconstruction.

The small incision technique is accomplished by making a number of short incisions on the medial and lateral sides (situated towards the midline, and outward from the midline of the body) of the Achilles tendon, adjacent to the site of the rupture. Sutures are passed through the incisions to form a lattice-like arrangement of interlocking sutures. While this approach results in a less unsightly scar, a higher tendency to re-rupture as compared to open techniques, and greater potential of complication (entrapment of nerve, misalignment of tendon ends), makes this option less attractive for the kendo man or woman who expects high dynamic loads to their Achilles tendons.

Open repairs to the tendon consist of making a long incision directly over the site of the injury, and accessing the ruptured tendon directly. Repair methods are numerous, but all essentially amount to suturing the proximal and distal (upper and lower) tendon stumps together, taking care to appose them accurately to provide for torsion free, longitudinally correct, axial alignment.

In traumatic failures, and in cases in which the ruptured tendon had been mis-diagnosed or neglected for some time, the unstable gastrocnemius commonly retracts proximally, up and away, creating a gap between the ruptured ends. In this case augmentation may be necessary. Augmentation may also be warranted in cases where damaged tissue is extensive, and damaged or disorganized fibrous tissues must be rejected, or cut away.

Direct repair requiring augmentation, depending on extent, may move into the realm of tendon reconstruction. In cases where extant tissues are inadequate in themselves to facilitate repair, augmentation actually serves to recreate insufficient portions of the anatomy to restore normal function.

Augmentation methods and materials are quite varied and elaborate. A simple method is the use of stainless wire, two strands extending from a bone screw set into the calcaneus, passed through the tendon longitudinally, to a point proximal to the rupture site, and wound together to serve as the upper anchor. Other methods of augmentation consist of autogenous grafts (materials harvested from some other part of the body of the same patient,) allografts (graft material originating from a donor other than the patient,) and synthetic materials (such as carbon fiber, polyester, and other synthetic fabric weaves.)

Autogenous grafts are commonly harvested from an adjacent lower leg tendon; however, any tedonous tissue of sufficient length and cross section can be suitable. As allografts and synthetic graft materials are not permitted due to Japanese law, where I am practicing, I cannot offer direct experience; however, based on published data, it appears that the use of allografts and synthetic grafts result in higher incidence of complications and rejection than do autogenous grafts.

Recently, the development of bio-engineered materials, and advances in genetic engineering are producing some promising results. It seems certain that in the future, doctors will be able to use “off the shelf” organic collagen graft material, or have organic grafts engineered from their patient’s own genetic information. This is especially attractive in that additional invasion to the patient’s body would not be necessary, and concurrent care and rehabilitation for the harvest site would be eliminated.

Application techniques, anchoring methods, suturing, closures, and possible skin grafts that may be used are extensive. The minute details of techniques, instruments, and medication, are beyond the scope of this article, but in general, augmentation and reconstruction utilise grafts, to bridge or reinforce injured or inadequate areas to provide for continuous tissue from gastrocnemius to calcaneus. They may include insertion to, application over, or complete replacement of portions of the original Achilles tendon. Anchoring techniques include suturing, stapling, screw fixation, and/or in combination with bone tunnel apposition.  The specific approach selected will be greatly determined by the experience and technical abilities of the surgeon. Whereas a more extensive procedure might be attractive in some ways, the simplest and shortest period in which the wound area is “open,” or exposed is also desirable. The surgeon weighs all these aspects upon first determination that surgical intervention is indeed necessary. It is at this early point that the surgery candidate should first discuss with the surgeon the various options that are available.

The post-operative recovery and rehabilitation course consists initially of immobilization, elevation, and cryo-therapy (continuous low temperature coolant passing over the surgery site). In particular, elevation and cryo-therapy serve to minimize the edema that traps the fluids that contribute to the development of fibrous scar tissue. Scar tissue tends to have lower vascularity, resulting in lower tensile strength, and scar tissue does not propagate nerve signals as efficiently as healthy vascular tissue. Bandages are changed often, with great attention paid to maintaining a sterile environment for complication-free healing.

prostheticsFollowing a period of about one to two weeks, the doctor will remove the immobilization and make an examination by inducing passive articulation (passive in that the patient does not exert any force) of the ankle. Typically, range-of-motion is limited and a great deal of soreness yet remains; however, even at this early stage, PT and rehabilitation are initiated.  Passive stretching exercises are performed in conjunction with certain modalities.  Ultrasound therapy, hot-pack therapy, and massage, to name just a few, are utilised to stimulate blood flow, sending exhausted materials and gases away, and sending nutrients and fresh oxygen in to the wound bed. By the third week the superficial wound has healed and PT and rehabilitation may proceed in accelerated fashion. The patient continues with assisted passive exercises to increase the range-of-motion, commences active motion, exerting force against the therapist’s controlled resistance, and begins partial weight bearing walking (touch to 1/3 body weight) with crutches. Beginning week 5 weight bearing is increased to 1/3 to 1/2 body-weight. By week six, patients are usually capable of 2/3 to full weight bearing gait, exerting their full force during ankle flexion, while regaining the greater part of range-of-motion. From this point on, the PT and rehabilitation regimen closely approximates that of the conservative, non-operative course described earlier. A typical time frame for the operative approach usually spans 5 to 6 months from surgery to full return to kendo activity.

An especially critical point in the recovery process, in both the conservative and surgical approaches, is reached around ten weeks time. Tissues damaged at the time of the injury that are necrolising (perishing) peak at this stage in which the body is remodeling new tissues.  These tissues are dying-off at the same time patient confidence, and the desire for a more accelerated recovery, are beginning to increase. We see a tendency in patients to re-rupture their tendons at this point. Such being the case, I offer the patient education about his or her condition, and strongly reinforce our PT-rehabilitation department’s measured approach to that patient’s recovery regimen.

During the 9th through 11th week in particular, the period in which necrolised tissues are being excised, and new muscles formed, the highest volume of blood flow possible, while controlling impact and loads, is desirable. Modalities such as massage, and ultrasound therapy are utilised extensively for increasing blood flow. However, a physiological approach being the best, I strongly advocate aqua-therapies, in which water resistance and buoyancy are utilised to control loads and minimize potentially catastrophic impact. My clinic is currently in the process of installing the first of several planned aqua-therapy pools for this purpose.

During the late stages of recovery, the kendo man/woman must return to activity in a staged fashion, in accordance with doctor’s and PT/rehabilitation therapist’s guidance. Great care must be taken to regain strength, endurance, timing and coordination, before attempting pre-morbid levels of activity. Once normal walking is restored, I restrict kendo activity to suburi (repetitive, non-impact striking motion exercise), and ashi-sabaki (foot-work exercises) without any jumping or fumi-komi (stamp to floor), for at least two or three weeks. Depending on the condition of the patient, activity is expanded to basic uchikomi-geiko (controlled striking exercise in which the opponent creates clear opportunities to strike, without contest), and so forth. Unrestricted ji-geiko (free combat between participants) and shiai (competition match) are allowed only at the end of the final stage, at the time the patient demonstrates complete recovery.

Both the conservative approach and the operative course have advantages and drawbacks.  Some studies indicate that patients who undergo conservative therapy have lower push-off strength as compared to surgical patients, and other data suggests higher incidence of re-rupture as opposed to surgical approaches; however, shorter absenteeism from work, avoidance of hospital stay and related expenses, lower rate of complications than invasive procedures, faster return to activities of daily life, and the absence of unsightly scaring make the conservative approach a good option for some patients.

The surgical option has some drawbacks, such as the potential for various complications including infection, and failure of skin grafts to heal properly (as applicable), scaring, which may be a concern for those who’s appearance is a critical factor, (models, gymnasts, dancers, heelless shoe wearers, etc.). On the other hand, the immediate restoration of viable tissue to original anatomic geometry, providing for good longitudinal alignment and proper tensioning, the high probability of good vascularity due to excision of disorganized and/or fibrous tissues (especially in cases of mis-diagnosed or neglected injuries), backed by some data which would suggest lower re-rupture rate, the surgical approach is certainly attractive to the kendo man or woman. Particularly in cases of chronic re-rupturing tendons, the operative course is suggested. Once a partial or complete rupture of the Achilles tendon is diagnosed, all these factors should be carefully discussed with the medical caregiver.

All these things said, it should be kept in mind by the kendo practitioner that prevention is the best medicine. Lifestyle and activities of daily life are the greatest contributing factors of Achilles tendon ailments. The amount of daily activity, jogging, cycling, or even evening strolls can greatly influence the condition of the lower leg structure.

Statistically, in the general population, the highest probability for injury occurs in the white-collar male, 30 to 40 year old range, working in an air-conditioned office, with an essentially sedentary lifestyle. Although this may not typify the kendo man and woman, it certainly gives us an indication as to the factors that contribute to injury. Conversely, we see much lower rates of injury in 2nd and 3rd world nations, where males of comparative age have much greater daily activity, working their Achilles tendons throughout the day.

Persons with tight Achilles tendons should maintain a regular program of stretching, taking care not to “bounce” but rather to apply even, continuous, stretching for fifteen to 20 seconds per repetition, progressively increasing the degree of dorsiflexion with each subsequent repetition. As stated earlier, ankle function is related to posture and overall body function. The muscles and connective tissues of the posterior side of the body are sympathetic, that is, they all work in cooperation with each other. This relationship can be understood directly by performing a common seated hamstring-stretch (“toe-touches”). At the further-most point, the head is gently pulled down with the hands. If done properly, all the muscles and connective tissues from the erectors of the neck, back, bottom, hamstrings, and lower leg will be tensioned simultaneously. I advise inclusion of this type of stretching exercise to all athletes who come to my sports clinic, who have a potential for Achilles tendon injury.

All kendo practitioners should avoid regular high-heel wearing, as this habit contributes to shorter gastrocnemius and Achilles tendon length.

Other factors that can be controlled to good effect are the taking of sufficient rest on a daily basis, good, well-rounded diet, weight maintenance, avoidance of smoking, and discretion as to drug use.

Certainly, one factor that must be conditioned into the serious kendo man or woman is the correct execution of techniques, taking care to keep the left foot pointed in the direction of travel, and the heel raised slightly at the point of abrupt change in direction, or receipt of the opponent’s tai-atari. If all these precautions and preparations are taken, the kendoist is likely to enjoy trouble free kendo activity.

It is my hope that by the means of better understanding of Achilles tendon ailment related factors, we can reduce the incidence of injuries in the greater kendo community. If anyone should suffer from an Achilles tendon ailment, I hope the information included in this article will provide the base for informed discussion with his or her medical caregiver.

 

References:

D. Johnson, M. Morelli, “Achilles Tendon Rupture, Clinical Case Challenge”, Medscape Orthopaedics & Sports Medicine, 2001, Vol 5, No 3, 0607.01.

T. S. Atkinson, M. Easley, “Complete Ruptures of the Achilles Tendon, The Expert Opinion”, Medscape Orthopaedics & Sports Medicine, 2001,Vol 5, No 3, 0216.01.

R. L. Valmassy, Clinical Biomechanics of the Lower Extremities, St. Louis, Missouri, Mosby-Year Book, Inc., 1996; 80-83

R. M. H. McMinn, R. T. Hutchings, B. M. Logan, Foot & Ankle Anatomy, London, Times Mirror International Publishers, Ltd., 1996, 2nd ed; 105-107

F. Peterson Kendall, E. Kendall McCreary, P. Geise Provance, Muscles, Testing and Function, Baltimore, Maryland, Williams & Wilkins, 1993, 4th ed; 194-207.

R. A. Mann, M. J. Coughlin, Surgery of the Foot and Ankle, Vol 2, St. Louis, Missouri, Mosby-Yearbook, Inc., 1993, 6th ed; 809-817, 1181-1184

Achilles, Microsoft Encarta Online Encyclopedia, 2001