Hammertoe Deformity Treatment & Management

The choice of nonoperative treatment of hammertoe deformity is based on the flexibility of the deformity (see Medical Therapy). Similarly, surgical treatment of hammertoe deformity depends on the flexibility of the deformity (see Surgical Therapy). The magnitude of the deformity also affects surgical decision-making.

The indication for surgical treatment of hammertoe deformity is disabling pain that does not improve with adequate nonoperative treatment, including taping (for flexible deformity) and the use of accommodative footwear featuring a toe box of adequate depth (for fixed deformity). Surgical correction of an asymptomatic hammertoe may be considered at the time of hallux valgus correction.  

Absolute contraindications for surgery include active infection and inadequate vascular supply. The desire for cosmesis alone is not an accepted indication; the patient must understand that the goal of surgery is pain relief, not cosmesis. Inability to accommodate shoe wear restrictions and/or limitations is a relative contraindication.

As a general rule, flexible deformities are amenable to soft-tissue procedures, whereas rigid deformities require at least a component of bony intervention. Passively correctable deformity is amenable to Girdlestone-Taylor flexor-to-extensor tendon transfer. Fixed deformity requires either proximal interphalangeal (PIP) joint resection arthroplasty or PIP joint arthrodesis. Both flexible and fixed deformities also may require metatarsal shortening, metatarsophalangeal (MTP) joint resection arthroplasty, extensor tenotomy, or a combination of these procedures to achieve adequate correction. A rotational deformity may require the addition of derotational phalangeal osteotomy.

A metatarsal shortening osteotomy may have to be added for a dislocated MTP joint or MTP instability with synovitis. Metatarsal-shortening procedures are becoming more popular as adjuncts to hammertoe correction but have not yet been fully accepted. Choices are as follows:

• Traditional diaphyseal shortening
• Posterior translation of the metatarsal head along a transverse plane osteotomy at the metatarsal neck (Weil osteotomy)

The Weil osteotomy is technically easier and less prone to nonunion. Metatarsal shortening also changes the length relationships between the toe tendons and the ray and may help reduce a hammertoe deformity.

Other approaches to managing MTP joint synovitis, instability, subluxation, or dislocation include the following:

• MTP joint resection arthroplasty
• Plantar condylectomy
• MTP plantar plate reconstruction

Strapping of the toe with either tape or a commercially available hammertoe sling is helpful for a flexible deformity; however, it mandates the use of shoewear that will accommodate the straps or slings. The tape or sling is placed dorsally over the proximal phalanx, the MTP joint is plantarflexed slightly, and the tape or sling is secured plantarly. The strapping reduces the deformity by exerting a plantarflexion force at the MTP joint, resulting in compensatory extension of the PIP joint.

Fixed deformities are not amenable to strapping, because the deformity cannot be corrected. Extra-depth footwear is necessary to minimize pressure dorsally over the affected toe(s). Lace-up shoes are more comfortable than slip-on shoes (eg, loafers) because a slip-on shoe is necessarily tight in the forefoot to maintain its fit.

Metatarsalgia, or pain over one or more metatarsal heads, may occur with significant deformity. This pain may be alleviated by using an arch pad in the shoe that may redistribute weightbearing force away from the metatarsal heads.

Patients often ask about physical therapy. Although no reliably effective physical therapy program for hammertoe deformity has been described, it may be nonetheless be useful for the patient with a flexible deformity to perform passive stretching exercises.

The flexibility of the deformity determines which technique is appropriate for correction. A flexible deformity of small magnitude may be amenable to a flexor tenotomy. No more than a small flexion deformity of the PIP joint should be present, with no subluxation of the MTP joint. A flexible deformity of greater magnitude requires a Girdlestone-Taylor flexor-to-extensor tendon transfer. ^[6] This method functions in the same way as taping or strapping a flexible hammertoe. Pin fixation is necessary for 4-6 weeks after surgery.

A fixed deformity requires at least resection arthroplasty of the PIP joint. ^[7] The goal is to shorten the toe and thereby decrease the deforming forces of the contracted soft tissues. As the magnitude of the deformity increases, additional procedures, such as flexor tenotomy, extensor tenotomy, MTP joint release or arthroplasty, and metatarsal shortening may be necessary. Pin fixation is necessary for 4-6 weeks after surgery. ^{[8, 9, 10]}

MTP arthroplasty includes resection of 2 mm of the metatarsal head articular surface and pinning of the toe across the MTP joint. It is theorized that the resulting arthrofibrosis stabilizes the MTP joint.

Plantar condylectomy of the metatarsal head may have to be added for plantar metatarsal head pain without instability or synovitis. Plantar condylectomy with pinning across the MTP joint helps reduce plantar prominence; the prominence may cause pain or callus over the second metatarsal head. Removing the condyles results in a bleeding cancellous bone surface on which the attenuated plantar plate readheres and contracts to stabilize the MTP joint.

MTP plantar plate reconstruction is a more anatomic stabilization of the MTP joint. Reconstruction of the plantar plate is an increasingly popular popular addition to metatarsal shortening when MTP instability is present.11 There is evidence to suggest that the plantar plate has some ability to heal these repairs. ^[11]

Metatarsal-shortening procedures are most likely to be effective in a foot with a long second metatarsal when second hammertoe is accompanied by pain or plantar callus over the second metatarsal head or when MTP instability and synovitis are present. To achieve adequate correction, it may be necessary to combine other procedures (PIP resection arthroplasty, Girdlestone-Taylor flexor-to-extensor tendon transfer) with the metatarsal shortening. If MTP instability is present, then plantar plate reconstruction should be added.

PIP joint arthrodesis is currently performed with regularity. ^{[12, 13]}  Studies are needed to evaluate its results against those of PIP joint resection arthroplasty. ^[14] Cockup deformity is a frequent complication, especially when significant MTP hyperextension is present preoperatively. 

Special consideration is necessary when hallux valgus accompanies second hammertoe deformity. (See the image below.) Even if the hallux valgus and bunion are asymptomatic, hallux valgus correction is necessary to minimize the risk of recurrence of the second hammertoe.

When rotational deformity accompanies hammertoe deformity, rotational or angulatory deformity of the involved phalanx may be necessary.

Resorbable pins have been considered for hammertoe correction fixation to avoid the necessity of pin removal in the office. Their strength in this application has not yet been rigorously studied, but success with resorbable pins and screws for other forms of foot and ankle surgery is encouraging.

K-wire fixation is a common, effective, and relatively inexpensive means of treating hammertoe deformity. ^[15]  (See the image below.) Some have expressed concerns about possible complications associated with K-wire fixation, which have led to the development of a number of permanent implants for fixation. ^{[16, 17]}  Although various intramedullary implants (eg, the ToeGrip and the SmartToe) have yielded good results, they remain relatively costly and have not yet been shown to confer clear advantages with respect to pain levels, patient satisfaction, foot-related function, or surgical complication rates. ^{[18, 19, 20]}

Preparation for surgery

Preoperative evaluation includes assessment of the following:

• Circulation, sensation, flexibility and magnitude of the deformity
• Stability of the MTP joint
• Associated deformities
• Metatarsalgia

Palpable pulses indicate an excellent prognosis for healing. Doppler studies should be obtained if pulses are not palpable. An ankle-brachial index (ABI) greater than 0.65 or a toe pressure greater than 40 also indicates a good prognosis for healing. A severe, long-standing, fixed hammertoe deformity can become ischemic when corrected as a consequence of traction on the digital arteries caused by straightening the toe.

Traction on the digital nerves can result in neurapraxia; therefore, preoperative knowledge of the sensory status of the toes is imperative. Patients with sensory neuropathy and good circulation are at risk for Charcot neuroarthropathy of the forefoot or midfoot after surgery. These patients are typically diabetic.

Associated deformities may require simultaneous surgical treatment. An apparent rotational deformity may actually be due to an angulatory deformity of the proximal or middle phalanx and should be assessed carefully on physical and radiographic examination. The location of metatarsalgia should be known preoperatively so that the patient can be counseled about postoperative expectations, because relief of metatarsalgia after hammertoe correction is unpredictable.

Although the clinical data are limited, it has been argued that perioperative antibiotic prophylaxis is not necessary for isolated forefoot procedures (eg, hammertoe correction) in the absence of risk factors (eg, immunodeficiency or diabetes mellitus). ^[21]

Operative details

Flexor tenotomy

Flexor tenotomy is typically performed via a plantar stab incision at the distal interphalangeal (DIP) joint. The scalpel is centered medial to lateral, and the flexor tendon is transected at its insertion onto the plantar base of the distal phalanx. The PIP joint then is hyperextended to free any adhesions between the flexor tendon and the plantar plate and collateral ligaments of the PIP joint. A smooth 0.045-in. Kirschner wire (K-wire) is then placed in a retrograde manner from the tip of the toe just plantar to the nail plate across the DIP and PIP joints while these joints are maintained in neutral extension. ^[22]

Bouche and Heit found that flexor digitorum longus (FDL) tendon transfer for combined plantar plate and hammertoe repair was viable in treating severe, chronic sagittal plane instability of the internal lesser MTP joints. ^[22]

In a study of 54 patients with a proximal planterflexion deformity of the second toe, Frey et al described a percutaneous technique that combined (1) FDL tenotomy, (2) plantar capulotomy for PIP joint release, and (3) proximal phalangeal osteotomy. ^[23] In the 24 cases where an extension deformity of the MTP joint was present, tenotomy of the extensor digitorum longus (EDL) and extensor digitorum brevis (EDB) was performed. At a mean follow-up of 30.7 months, the satisfaction rate and the rate of morphologic correction were both 89.5%. Active plantarflexion was preserved in 86%.

Girdlestone-Taylor flexor-to-extensor tendon transfer

Girdlestone-Taylor flexor-to-extensor tendon transfer consists of splitting the FDL tendon in half after detaching it from the plantar base of the distal phalanx via a percutaneous stab incision. ^[6] A second transverse incision is made plantarly at the MTP joint, through which the detached flexor tendon is harvested. It then is split longitudinally along its raphe.

A longitudinal incision is made dorsally over the proximal phalanx. A curved hemostat is passed along the bone on each side of the proximal phalanx to prevent neurovascular injury. Each hemostat grasps one half of the split tendon, and the halves are pulled through dorsally.

The interphalangeal (IP) joints are positioned in neutral extension, the MTP joint is slightly plantarflexed, and a 0.062-in K-wire is passed in retrograde fashion from the tip of the toe just plantar to the nail plate, across the IP and MTP joints, and into the metatarsal. Tension is applied to the transferred tendon halves while slight ankle plantarflexion is maintained, and the halves are sutured to the dorsal soft tissues over the proximal phalanx.

PIP joint resection arthroplasty

PIP joint resection arthroplasty is performed via either an elliptical incision directly over the joint or a longitudinal incision. Recurrence is theoretically less common with the elliptical incision, and the procedure is easier. A longitudinal incision is necessary if exposure of the DIP joint, the MTP joint, or both is necessary. ^[7]

The elliptical incision is made directly over the PIP joint through skin, tendon, and joint capsule. The incised soft tissues are excised. The head of the proximal phalanx is exposed through release of the collateral ligaments and the plantar plate. A bone cutter, rongeur, or microsagittal saw is used to remove the head of the proximal phalanx at the level of the phalangeal neck.

A smooth 0.045-in. K-wire is placed in an antegrade manner through the middle and distal phalanges while DIP joint extension is maintained. It is then placed in a retrograde fashion into the proximal phalanx while PIP joint extension and distraction are maintained. The skin, tendon, and capsule are closed together as a single layer.

A study by Yassin et al compared PIP joint resection arthroplasty and K-wire fixation (n = 265; 454 toes) with percutaneous diaphyseal osteotomy of the middle and proximal phalanges and tendon release (n = 87; 221 toes). ^[24]  The two groups were similar with respect to abnormal healing rates, alignment, and patient satisfaction, but patients in the percutaneous group had fewer infections.

Additional procedures

If adequate correction of a fixed hammertoe deformity cannot be achieved with PIP joint resection arthroplasty, additional procedures are necessary. First, extensor tenotomy is performed at the MTP via a dorsal stab incision. Releasing both the extensor digitorum longus (EDL) and the extensor digitorum brevis (EDB) is important. If correction remains inadequate, release of the dorsal MTP joint capsule is performed through the same stab incision. Finally, if additional correction is necessary, the incision is extended and MTP arthroplasty performed.

The Weil osteotomy is an effective metatarsal-shortening method. ^[25] The osteotomy is started at the junction of the articular cartilage and dorsal shaft of the metatarsal and continued along a plane parallel to what would be the position of the floor if the patient were weightbearing. The metatarsal is translated proximally about 3-4 mm, and screw fixation is placed. The redundant dorsal cortex is then removed.

Plantar plate reconstruction is combined with Weil osteotomy when MTP instability is associated with hammertoe deformity. The plantar plate is detached from the base of the proximal phalanx, and a suture is placed transversely through the plantar plate proximal to the detachment point. The suture is then passed through drill holes in the proximal phalanx from plantar to dorsal while reduction of the MTP joint is maintained.

MTP arthroplasty comprises arthrotomy and exposure of the metatarsal head. A 2-mm wafer of articular surface is removed with a microsagittal saw.

When any of these supplemental procedures are necessary, a smooth 0.062-in. K-wire should be substituted for the 0.045-in K-wire, and it should be placed across the MTP joint into the metatarsal.

The pin is bent and cut to length outside the skin. The bent tip should terminate dorsal to the nail plate, potentially preventing proximal migration of the pin. A pin cap protects the sharp end of the cut pin so that it does not catch on the patient's bed sheets. A compression dressing is applied. Plaster immobilization is rarely, if ever, necessary. A hard-soled postoperative shoe is provided. Elevation of the foot with the toes above the nose is essential to minimize swelling, which can cause pain and delay wound healing.

Complications of hammertoe correction surgery include the following:

• Infection
• Delayed wound healing
• Recurrent deformity
• Molding
• Loss of fixation
• Neurovascular injury
• Metatarsalgia

Superficial wound infection is not uncommon, given that skin redundancy often occurs after correction of the deformity. Superficial wound infection typically responds to local wound care and oral administration of antibiotics to which typical skin flora are sensitive. Deep infection often requires irrigation and debridement. In severe and complicated cases (eg, in diabetics), deep infections may necessitate amputation.

Pin migration is a known complication. Proximal migration, though more worrisome, is less common. In cases of distal migration, the pins should not be readvanced into bone, so as to avoid pin-associated infection. Severe redness and swelling of the entire toe with drainage suggests infection around the pin. Usually, removal of the pin and a 10- to 14-day course of oral antibiotics to which typical skin flora are sensitive are sufficient. The toe must be taped (see Medical Therapy), and a second piece should be added to maintain extension of the IP joints. Taping should continue as long as the pin would have remained in place.

Delayed wound healing usually occurs in individuals who smoke or in persons with peripheral vascular disease or diabetes. Prevention by means of a thorough preoperative evaluation and optimization minimizes the risk of delayed wound healing. Deep infection in a slowly healing wound should be suspected. Radiography, bone scintigraphy, and indium-labeled white blood cell scanning are not helpful during the early postoperative period. Essential components of treatment include the following:

• Vigilant follow-up care
• Debridement when necessary
• Local wound care
• Therapy with oral antibiotics to which typical skin flora are sensitive; knowledge of local community and hospital antibiograms is helpful in guiding empiric therapy ^{[26, 27]}

Recurrent deformity is common and is typically caused by inadequate correction or use of inappropriate footwear. Salvage commonly requires PIP resection arthroplasty combined with extensor tenotomy and either MTP release or MTP arthroplasty. The results of revision surgery are less reliable than those of primary surgery.

Cockup deformity may occur after PIP arthrodesis if MTP hyperextension is not corrected, or after Weil osteotomy. Floating toe deformity is also a complication of Weil osteotomy, especially when combined with PIP arthrodesis. ^[28]

So-called sausage toe may occur after Girdlestone-Taylor tendon transfer (see the image below).

Neurovascular injury is extremely rare and typically results from complete correction of a long-standing, severe deformity. Traction from the correction on the neurovascular bundle can cause neurapraxia, vasospasm, or digital artery avulsion.

Because of the collateral circulation, ischemia rarely results. Nevertheless, it is necessary to ensure that the patient does not leave the operating room until all of the toes have "pinked up." If capillary refill does not occur in a given toe, the dressing should be loosened. If this is unsuccessful, the toe should be warmed. If capillary refill does not occur, the pin should be bent to partially recreate the deformity, thereby reducing tension on the neurovascular bundle. The pin may have to be removed. Finally, exploration for persistent bleeding or a compressive hematoma may be necessary.

Nerve injury can result in anesthesia, dysesthesia, or hyperesthesia. Anesthesia is well tolerated, and dysesthesia is accepted, but hyperesthesia can be disabling and may represent a variation of chronic regional pain syndrome. Neurogenic pain may be of sufficient severity to warrant toe amputation.

Metatarsalgia, a complication of many forefoot procedures, develops as diffuse pain over the metatarsal heads. It is often caused by an altered gait pattern occurring after the patient resumes weightbearing in a regular shoe. Metatarsalgia is often self-limiting. However, patients may require orthotic management consisting of a cushioned longitudinal arch support to relieve the metatarsal head.

Weightbearing, as tolerated in a hard-soled shoe, is permitted when the pin does not cross the MTP joint. Weightbearing is not permitted when the fixation pin crosses the MTP joint. Footwear may be advanced as tolerated once the pin is removed (typically 4-6 weeks after surgery). A compressive dressing is used until the sutures are removed 10-14 days after surgery. The patient should understand that mild-to-moderate swelling persists for many months after surgery and limits footwear options until it has resolved.

All lesser-toe procedures result in stiffness of the MTP and IP joints. Because some stiffness is intentional for maintaining lasting correction of the deformity, exercises to improve range of motion should be used judiciously. Some stretching may be necessary to improve mobility, but general mobilization ("real-life physical therapy"), as tolerated, is usually sufficient.

Patients should be counseled to continue wearing shoes of adequate length and depth, with a rounded or squared toe area to minimize the risk of recurrence. Temporary plantar foot discomfort may occur for several months after surgery in patients who undergo an MTP joint procedure. The wearing of stiff-soled shoes with a metatarsal pad is usually sufficient until the symptoms abate.