Tendon Transfers In the Foot and Ankle, An Issue of Foot and Ankle Clinics

Eric M. Bluman, Chris Chiodo

Description

Principles of Balancing the Foot with Tendon Transfers, Basic Science of Tendon Transfers, Tendon Transfer for Ankle Equinus and Equinovarus, The Bridle Procedure, The Uses of Tendon Transfers to Correct the Cavus Foot and Ankle, Tendon Transfers About the Hallux (Jones, FHB, Hallux Varus), Forefoot Tendon Transfers, Tendon Transfers in Polio, Management of Equinovalgus Deformity, The Management of Spastic Equinovarus Deformity Following Stroke and Head Injury.

Sujets

• Medical
• Médecine
• Orthopedics

Informations

• Publié par: Saunders
• Date de parution: 28 septembre 2011
• Nombre de lectures: 0
• EAN13: 9781455709243
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Foot and Ankle Clinics , Vol. 16, No. 3, September 2011
ISSN: 1083-7515
doi: 10.1016/S1083-7515(11)00067-2

Contributors
Foot and Ankle Clinics
Tendon Transfers in the Foot and Ankle
GUEST EDITORS: Christopher P. Chiodo, MD
Eric M. Bluman, MD, PhD
CONSULTING EDITOR: Mark S. Myerson, MD
ISSN  1083-7515
Volume 16 • Number 3 • September 2011

Contents
Cover
Contributors
Forthcoming/Recent Issues
Foreword
Preface
Principles of Balancing the Foot with Tendon Transfers
The Basics and Science of Tendon Transfers
Tendon Transfers for Equinovarus Deformity in Adults and Children
The Bridle Procedure
Tendon Transfers for the Adult Flexible Cavovarus Foot
Tendon Transfers about the Hallux
Forefoot Tendon Transfers
Management of Paralytic Equinovalgus Deformity
The Management of Spastic Equinovarus Deformity Following Stroke and Head Injury
Index
Foot and Ankle Clinics , Vol. 16, No. 3, September 2011
ISSN: 1083-7515
doi: 10.1016/S1083-7515(11)00069-6

Forthcoming/Recent Issues
Foot and Ankle Clinics , Vol. 16, No. 3, September 2011
ISSN: 1083-7515
doi: 10.1016/j.fcl.2011.06.007

Foreword

Mark S. Myerson, MD, Email: [e-mail]
Institute for Foot and Ankle Reconstruction at Mercy, Mercy Medical Center, 301 St. Paul Place, Baltimore, MD 21202, USA


Mark S. Myerson, MD, Consulting Editor
The uses of tendon transfers is a fascinating topic. Although we do not treat as many paralytic deformities as were corrected surgically in the era of polio, there are many circumstances where tendon transfers remain an essential part of the operative management of deformity. The correction of foot and ankle deformity by means of a correctly performed tendon transfer can be satisfying for both the surgeon and the patient. The goal of any tendon transfer is to create a stable, functioning, and plantigrade foot, and this goal applies to every tendon transfer performed for paralysis because the correction of deformity, the improvement of function, and the establishment of a plantigrade foot are essential.
I would like to consider the patient with cavoequinovarus deformity, the result of hereditary sensory motor neuropathy (CMT), as an illustrative example of mismanagement of deformity correction. I have learned over the decades that a triple arthrodesis is an excellent procedure, provided the foot is correctly balanced with additional osteotomy and tendon transfer. The triple arthrodesis gained a poor reputation for correction of the cavus foot since recurrent deformity was common. However, for the majority of these patients for whom deformity recurred, no tendon transfer was performed because it was felt that the posterior tendon tibial tendon for example was too weak to be of any benefit. However, the posterior tibial tendon inserts distal to the talonavicular joint, and unless the tendon is transferred, the medial foot deformity will gradually recur into adductovarus or equinovarus. Integral to the success of any of these procedures is a corrected foot, a plantigrade hindfoot relative to the forefoot, and muscle balance. Even with perfectly executed surgery, if the posterior tibial muscle is overactive relative to the evertors of the hindfoot, the foot will ultimately deform. Even though the posterior tibial muscle may not be strong enough to support a paralytic equinus deformity, it should nonetheless be transferred, usually to the dorsum of the foot.
When any tendon transfer is planned, one must consider the relative muscle strengths and tendon excursion of every functioning muscle, no matter how weak it may appear; the positioning of the tendon to be transferred relative to the rest of the foot; the proper tensioning of a transferred tendon; and the pull-out strength necessary to secure the tendon transfer. Optimally, a tendon transfer should approximate the strength and excursion of the motor unit it is trying to replace, but this can be rarely accomplished with a single tendon. Therefore expecting the extensor hallucis longus muscle to replace the anterior tibial muscle, or the flexor digitorum longus muscle to replace the posterior tibial muscle, is unrealistic.
Most muscles will lose a grade of power when transferred, particularly if the transfer is not phasic (a tendon that is primarily a flexor and is transferred to function as an extensor). As an example, a PTT transfer to the dorsum of the foot to regain dorsiflexion strength is not phasic, and muscle power is lost. It is always preferable to use a muscle that is phasic because less “reeducation” of the muscle is required, rehabilitation is facilitated, and less strength of the muscle is lost in the transfer. Typically in a PTT transfer performed through the interosseous membrane to the dorsum of the foot for correction of a flaccid paralysis muscle strength is lost. The same applies to another nonphasic transfer such as the peroneal muscle(s) to substitute for absent ankle dorsiflexion. I have been very encouraged with the use of nonstandard tendon transfers. Basically, if there is deformity as a result of tendon imbalance, transfer the involved tendon, even if it is slightly weak. Where you transfer it to is not as important as removing the deforming force. A tendon transfer will then have two benefits: the one is the removal of the deforming force and thereby lessening deformity, and the second is to take advantage of the muscle that is transferred to further improve the function of the foot. A good example of this is the transfer of the flexor hallucis longus (FHL) to the base of the proximal phalanx for correction of a flexible claw hallux deformity. By removing the FHL from its attachment to the distal phalanx, the flexion effect on the interphalangeal joint is minimized, and the transfer into the base of the proximal phalanx increases flexion strength of the hallux since the intrinsic muscles (in this case, the flexor hallucis brevis) are rarely functioning.
It is difficult to know how tight the tendon transfer is to be when secured to the bone. If it is fixed at maximal elongation, the tendon transfer acts more like a tenodesis, although it always stretches out. However, if it is fixed in its relaxed state, it cannot generate adequate tension to pull effectively. Generally, I prefer to insert the tendon under more tension than relaxation because some stretching out of the muscle always occurs. The converse however does not apply, and muscle strength can never be regained if the transfer is too loose. Finally, if transferred underneath a retinaculum that functions as a pulley, this increases the effective tendon excursion (range of motion). However, this transfer brings the tendon closer to the ankle or subtalar axes and diminishes the lever arm and the subsequent strength of the transfer. With a subcutaneous position of a tendon transfer, excursion is decreased, but motor strength is maximized because of the greater distance from the joint axes and the resulting greater lever arm. In general, a tendon is always transferred in a subcutaneous position. Quite apart from the biomechanical advantage outlined here, there is a greater likelihood of the tendon ultimately getting stuck if the transfer is performed under the retinaculum.
Wherever possible, I perform a transfer using a tunnel with a bone tendon–bone interference fit of the tendon. A more simple attachment of the tendon to the periosteum is never as secure. This does mean however that sufficient tendon length is present in order to insert the tendon in the correct location, but simultaneously has enough length to insert it into a bone tunnel. The options for securing the tendon in the tunnel include an interference fit with a bone peg, a screw, either metallic or bioresorbable, or a suture anchor. Generally, I use both since most of these patients have relative osteopenia and I do not think that an interference screw provides adequate fixation to support the transfer. This fixation of the tendon is very important, since rehabilitation with weight-bearing and passive range-of-motion exercises may begin once the sutures are removed, and the strengthening and reeducation that needs to be initiated may start sooner. Rehabilitation is essential regardless of the type of transfer, although this is easier to accomplish if the transferred tendon is in phase with the muscle it replaced.
Foot and Ankle Clinics , Vol. 16, No. 3, September 2011
ISSN: 1083-7515
doi: 10.1016/j.fcl.2011.08.002

Preface

Christopher P. Chiodo, MD, Email: [e-mail] , Eric M. Bluman, MD, PhD, Email: [e-mail]
Brigham Foot and Ankle Center, Department of Orthopaedics, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
Tendon transfers have been an invaluable part of the orthopedic armamentarium for more than a century. These procedures have great utility in correcting deformity, establishing or augmenting motor function, and generating a tenodesis effect. As such, they have become some of the most frequently performed orthopedic foot and ankle surgeries. Their success provides great satisfaction to both patient and surgeon alike.
Despite their utility and longevity, there remains a relative paucity of literature on many aspects of tendon transfers about the foot and ankle. Perhaps this is because there is just as much art as science to performing tendon transfers, or maybe it is due to the degree of difficulty in performing properly balanced procedures. Certainly, there are few, if any, cookbook approaches to a successful tendon transfer.
Fortunately, foot and ankle orthopedic surgery is replete with the wisdo