Keeping Things Simple and . . . Speedy
A Dozen Paradigms About Toe Tenotomies
While toe deformities may appear to be unimportant, they can have serious consequences. This is the situation especially in patients with diabetes who have neuropathies. A small ulcer can evolve to osteomyelitis of the phalanges, septic joints of the toes, ascending tenosynovitis and progressive necrotizing soft tissue infections. Malperforans ulcers are invariably the consequence of underlying bone and joint deformities. The pathology in the toes is no different than when they occur in the foot and ankle. Consequently, early attention to correction of gnarled toes is an essential proactive wound prevention measure for the insensate foot that has more than cosmetic ramifications. This article describes the anatomy of claw, hammer, and mallet toes, explains the pathophysiology that leads to forefoot and toe wounds, and provides a dozen paradigms about tenotomies to manage the axial (toes in-line with the metatarsals) deformities of the toes.
Figure 2. Bone and joint anatomy of clawed, hammer, and mallet toes
Legend: Axial deformity classification of toes based on levels of joint involvement. Table 2 explains the pathophysiology causing the deformities. Red arrows indicate levels of contractures. Yellow oblongs indicate sites of ulcerations. The clawed toe is the cause of the malperforans ulcer under the metatarsal head— note the dorsal subluxation of the proximal phalanx, which "drives" the MT head downward.
Key: DIP = distal interphalangeal, HE = hyperextenstion, HF = hyperflexion, MTP = metatarsal phalangeal, PIP = proximal interphalangeal joint
CLASSIFICATION OF AXIAL TOE DEFORMITIES
The classification of axial toe deformities is straight- forward (Figure 1). A hammer toe occurs with hyperextension at the metatarsophalangeal joint and flexion at the proximal interphalangeal joint with or without extension of the distal interphalangeal joint. A claw toe is present when the metatarsophalangeal joint is hyperextended and the proximal interphalangeal joint is flexed, similar to a hammer toe. However, the distal interphalangeal joint may also be flexed. In a mallet toe, the metatarsopha- langeal joint and proximal interphalangeal joints are unaffected, but the distal interphalangeal joint is flexed.
|Claw Toe||1) Hyperextensions at the metatarsophalangeal joint, 2)Hyperflexion at the proximal interphalangeal joint and 3) possibly at the distal interphalangeal joint||Releases of the flexor & extensor tendons; Joint manipulation|
|Hammer Toe||Hyperflexion at the proximal interphalangeal joint and possibly at the distal interphalangeal joint||Releases of the flexor tendons & joint manipulations|
|Mallet Toe||Hyperflexion at the distal interphalangeal joint||Releases of the flexor tendons & possibly joint capsule|
|Hyperextended Toe||Hyperextension at the metatarsophalangeal joint; intrinsic muscles maintain interphalangeal joint extension||Releases of the flexor tendons & possibly joint capsule|
PATHOPHYSIOLOGY OF AXIAL TOE DEFORMITIES
The pathophysiology of the toe deformities that leads to forefoot and toe wounds results from neuropathy. The essential problem is a motor neuropathy where fine muscle balance between flexor and extensor muscles is altered or lost. With loss of the intrinsic muscles which flex the toes at the metatarsophalangeal joints and extend the toes at the interphalangeal joints, hyperextension of the metatarsophalangeal joints occurs due to over-pull of the toe extensor muscles. Meanwhile, over-pull of the flexor muscles cause toe interphalangeal joint contractures (Table 1).
Consequences of the muscle imbalances include:
1) Retraction of the toes proximally onto the dorsum of the foot, 2) Dorsal subluxation of the proximal phalanges over the metatarsal heads, 3) Depression of the metatarsal heads into the forefoot fat pad with muscle activity, and 4) A malperforans ulcer develops as the plantar surface of the metatarsal head erodes from inside-to-outside with weight bearing because of the deformity, if not corrected (Figure 2). If the intrinsic muscles of the foot continue to function, but there is over-pull of the extensor muscles, the toes may remain straight, but be hyperextended at the metatarsophalangeal joints.
The hammer and mallet toe deformities occur because of over-pull of the flexor tendons and loss of the intrinsic muscle abilities to extend the interphalangeal joints. If the problem lies primarily with the short intrinsic flexors of the toes, the hammer toe deformity occurs and causes the toe tip to “drive” into the sole of the shoe. The consequence is a pressure sore at the tip of the toe. This typically progresses to a penetrating ulcer to the distal tuft and osteomyelitis of this structure (Figures 2, 3, & 4).
Figure 2: Pathophysiology of Clawed, Hammer, and Mallet Toes
Legend: Of note are the clawed toes with hyperextension at the metatarsal phalangeal joints and hyperflexion at the proximal interphalangeal joints.
Because of the muscle imbalances, the toes have been retracted proximally onto the dorsum of the foot resulting in dorsal subluxation of the metatarsal phalangeal joints and pulp pads of the toes tips not touching the floor when standing.
Over-pull of the long flexor muscles of the toes results in mallet deformity. When the combination of the above problems occur, the hyperflexed proximal interphalangeal joint (PIP) in association with the hyperextended metatarsophalangeal joint causes a pressure sore over the apex of the PIP joint (Figure 5). With progression, the ulceration erodes into the joint causing a septic joint and osteomyelitis. If unchecked the infection can track proximally along the tendon sheaths resulting in ascending tenosynovitis and progressive necrotizing soft tissue infection.
Figure 3: Toe Tip Wound from Hallux Malleolus
Legend: Because of the clawed hallux, the toe tip was "driven" into the patient's footwear. This resulted in a diabetic foot ulcer that penetrated to the distal tuft of the hallux and caused osteomyelitis with erosion of the bone (red arrows). A partial toe amputation was required to manage this problem. There was also a mallet toe deformity of the second toe as well as fungus infection of the hallux toenail.
Usually, a sensory neuropathy is associated with the motor neuropathy, especially in the patient with diabetes mellitus. However, other motor neuropathies have hereditary causes such as Charcot Marie Tooth disease. Acquired causes (such as the results of trauma and/or demyelinating causes, such as amyotrophic lateral sclerosis), may not have sensory neuropathy components to them. While a sensory neuropathy does not cause a deformity, it may delay the diagnosis of the deformity. The absence of pain may sidetrack the patient from seeking care until a complication arises such as obvious infection at the deformity site or systemic sepsis occurs. Consequently, any patient with sensory neuropathy in the feet and associated toe deformities should be informed of the need for proactive interventions anytime an impending pressure sore is observed in the forefoot and/or toes. Also, it is essential that all foot-care providers are also aware of this information and counsel their patients accordingly.
Figure 4: Toe Tip Ulceration from Clawed Toe
Legend: The reason for the toe tip ulceration is obvious from the examination. The clawed toe increased the contact pressure when standing and walking between the toe tip and the underlining supporting surface enough to generate a pressure sore over toe tip.
Note the flexor creases of the clawed toe are obscured because of the flexion contractures. We label this clinical finding the "hidden crease" sign.
PARADIGMS FOR EVALUATION AND MANAGEMENT OF AXIAL TOE DEFORMITIES
With the above considerations, and experiences with over 400 tenotomies of toe tendons (done by the first author) in the past dozen years, we want to reiterate some of the above information as well as share our “pearls” in the evaluation and management of axial toe deformities with the readers of Wound Care & Hyperbaric Medicine. A large review experience of toe tenotomy surgeries can be found in Tamir, et al’s article in Foot & Ankle International. Whereas some of the procedures need to be done in the operating room, we do the majority of tenotomies in our outpatient wound care programs. The following are 12 paradigms that relate to axial toe deformities and their management with tenotomies:
1. Often toes are retracted proximally onto the dorsum of the foot due to over-activity of the long extensor tendons. This leads to downward pressure on the metatarsal heads and is a precursor to mal perforans ulcerations (Figure 2). The retracted toe sign is an indication for toe extensor releases (Figure 4).
2. Manipulation of interphalangeal joint contractures should always be a component of the tendon release procedures (Figure 6). Occasionally, the manipulation results in avulsion of skin at flexor creases of the interphalangeal joints. All of these superficial wounds have healed without incidence.
3. In some instances, extensor tendon releases are difficult to perform in the presence of edema, scar, or hidebound skin. In these cases, we perform these procedures in the operating room, as described in the following text box.
4. Releases of extensor halluces longus tendons for managing clawing of the great toes have generally not been effective in managing mal perforans ulcerations of these toes. In such cases, the underlying bony deformities necessitate sesamoid planning or excision.
5. If the patient with a neuropathic foot is in the operating room for a foot surgery unrelated to toe deformities, then tenotomies should be recommended to the patient at the time of the pre-operative evaluation. We perform our toe flexor tenotomies at the level of the metatarsal head rather than at the proximal interphalangeal joint levels. The additional soft tissue padding (metatarsal head fat pad) affords more reliable healing rates compared to hidebound flexion joint creases.
6. With ankylosed interphalangeal joints, tenotomies may need to be supplemented with realignment interphalangeal joint resections. We also do this minimally invasively, as described in the following text box.
Our approach negates the need for maintaining alignment of the interphalangeal joint fusion with temporary placement of a Kirshner wire through the medullary canal and the potential problems it imposes, such as keeping the patient non-weight bearing, infection of the pin tract and/or breakage or bending of the pin.
7. Infrequently, toes straightened with enotomies develop recurrent deformities. In the pre- operative orientation for the patient, this should be mentioned. If necessary, second stage tenotomies and/or joint resections (see previous paradigm) are done.
8. Active toe flexion and extension for respective extensor and flexor tenotomies by the awake patient facilitates the releases. This makes the tendons taut like a bowstring (and sweeping the #11 scalpel blade transversely across the tendon in a pendulum-like fashion with the two-to three-mm skin incision as the pivot point) easy to release (Figure 7). Usually, audible and palpable sensations confirm the tenotomy is complete and verified by the patient being unable to actively flex or extend the toe. If the patient is insensate as is frequently the situation in patients with diabetes mellitus, no anesthesia is needed. If sensation is present, a field block with 1% lidocaine (without epinephrine) proximal to the incision provides adequate anesthesia for the procedure.
Figure 6: Toe Deformity Management with Joint Manipulation
Legend: Post-traumatic 90° flexion contracture (i.e. mallet toe) of distal interphalangeal joint of a 3rd toe. Toe could be straightened with manipulation, but because of fibroanklylosis of the joint, reduction could not be maintained.
Definitive manage requires a joint resection (see Paradigm #7)
9. Anticoagulation is not contraindication to doing these minimally invasive surgeries. In the anti-coagulated patients, we typically double the time we apply direct pressure to the operative site(s), i.e. ten minutes instead of five.
10. Advanced peripheral arterial disease even in those patients with barely perceptible Doppler detected pulses, has not been a contraindication for doing these minimally invasive tenotomies. After the tenotomies, we allow our patients to walk out of the office. Bandaging is minimal and done to maintain the toe in the corrected position, usually with weaving between the toes or horse shoe wrap under or over the toe depending on the correction desired.
11. After having dealt with many toe deformities with “textbook” management (i.e. correction utilizing flexor tendon transfers and arthrodesis of the interphalangeal joints) of clawed, hammer, and mallet toe deformities, the minimal invasive toe tenotomy procedures without question are our preferred recommendations (Figure 8).
Figure 7: Percutaneous Toe Extensor Tendon Tenotomy
Legend: Pressure placed on the end of the clawed toe (as the patient is asked to forcefully hyper extend his/her toes and ankle) causes the extensor tendon to bowstring over the dorsum of the foot.
This makes the tendon an easy target for transection. With 2 to 3 mm incision and the skin as a pivot point, the #11 scalpel blade is swept transversely in a pendulum-like fashion over the taut tendon. Audible and palpable sensations signal the release of the tendon and the release is confirmed by the patient being unable to actively extend the toe.
Figure 8: Percutaneous Toe Extensor Tendon Tenotomy
Legend: In the left-side photo the patient had the more traditional (textbook) approach for dealing with her claw toe deformities including rerouting the flexor tendons to the dorsums of the proximal phalanges, interphalangeal joint fusions and temporary percutaneous joint pinnings. Note the shortened 2nd and 3rd toes and their recurrent deformities. These toes were almost totally immobile. Thirty to 45 minutes surgical times, at best, are required to perform these procedures for each toe.
The right-hand photo shows the photos of previously clawed toes managed with tenotomies. Limited open for the extensor tendons and percutaneous for the flexor tendons. The patient elected to have the bilateral procedures done is one "sitting" in the operating room versus serial releases in the office. Although the toes are immobile, they remain straight, at normal length and not prone to develop ulcers. Not the mild recurrent hammer deformity of the little toe. If the patient so elects, this can be managed with a 2nd stage in-office percutaneous flexor tenotomy.
12. When patients are presented with the options of living with non-functional deformed toes at risk for developing ulcerations versus straight, cosmetically pleasing, not actively mobile toes not prone to ulceration, the answer is invariably the straight toe choice. This option is especially recommended for the patient with co- morbidities such as diabetes mellitus, peripheral artery disease, and peripheral neuropathy. Percutaneous and limited open (may be required for extensor tendons) tenotomies is the minimal invasive, quick-and-easy solution to achieve this goal.
Our approach to managing clawed, hammer, and mallet toes has been uniformly successful with almost 100% satisfaction in the patients. One non-anticoagulated patient did develop a hematoma at a single, open extensor tenotomy site, and a couple of patients had minor superficial skin dehiscence, which subsequently healed with minor care. No complications were associated with the solely percutaneous technique. Several patients required delayed secondary procedures, such as flexor tenotomies after their extensor tenotomies. If the procedures are performed in the office, clinic, or at bedside, no more than two tenotomies are done at any one time. At these venues, the patients are given prophylactic oral antibiotics for a day or two.
What surgical skills are needed to perform the percutaneous tenotomies? Surgeons familiar with foot anatomy and an understanding of the pathophysiology of the axial toe deformities are the logical choices. Although bowstringing tendons are easy to transect, more difficulty may be experienced with tendons “hidden” by fatty subcutaneous tissues, edema, scar tissue, or hidebound skin. For such situations, the tenotomies should be performed by a foot and ankle surgeon, especially when these conditions are present on the dorsum of the foot. For easily accessible tendons, any wound care giver with suturing and debriding experience should be able to perform the minimally invasive percutaneous procedures after being suitably mentored and found to be competent in doing the tenotomies.
Occasionally, a two-to three mm incision becomes extended because of patient movement or inexperience. If this occurs and the accidental incision is large enough, it can be easily approximated with a couple of small nylon sutures.
Another advantage of our minimally invasively, keep-it-simple, and speedy approach to axial toe deformities is its cost effectiveness. The charges are a fraction of what they would be when performed in the clinic or office setting rather than the operating room. Use of the operating room may cost $5,000-$10,000 versus the in-clinic, in-office procedure costing 1/10th to 1/20th of this. The paradigms described above demonstrate the considerations we address when providing this effective, cosmetically, pleasing and cost-effective option to our patients with clawed, hammer and/or mallet toes.
- Strauss, MB, Manji, KA, Stuart, SM, Manji AA. Bursa and Callus: Friend or Foe. Wound Care and Hyperbaric Medicine. 2013: 4(2): 13-28.
- Tamir E, Vigler M, Avisar E, Finestone AS. Percutaneous tenotomy for the treatment of diabetic toe ulcer. Foot and Ankle International. 2014: 35(1): 38-43.
- Coughlin, MJ. Lesser Toe Deformities. Mann’s Surgery of the Foot and Ankle. 9th ed. Philadelphia, PA: Saunders/Elsevier; 2014. p. 322-424.