You are in: eMedicine Specialties > Orthopedic Surgery > FOOT AND ANKLE Hammertoe DeformityArticle Last Updated: Mar 15, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Anthony Watson, MD, Assistant Professor of Orthopaedic Surgery, Department of Orthopedic Surgery, Foot and Ankle Program, Allegheny General Hospital Anthony Watson is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Medical Association, American Orthopaedic Foot and Ankle Society, Pennsylvania Medical Society, and Pennsylvania Orthopaedic Society Editors: Heidi M Stephens, MD, Associate Professor, Department of Surgery, Division of Orthopedic Surgery, Director of Diabetic Foot Clinic, Assistant Dean for Clinical Outreach, University of South Florida College of Medicine; Courtesy Joint Associate Professor, Department of Environmental and Occupational Health, University of South Florida College of Public Health; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Shepard R Hurwitz, MD, Executive Director Designate, American Board of Orthopaedic Surgery; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Jason H Calhoun, MD, FAAOS, Chairman, J Vernon Luck Distinguished Professor, Department of Orthopedic Surgery, University of Missouri Author and Editor Disclosure Synonyms and related keywords: claw toe, toe deformity, foot deformity, deformed toe, deformed foot lesser-toe deformity, deformity of the lesser toes, Morton foot, Morton's foot INTRODUCTIONSection 2 of 12
  Hammertoe deformity is the most common deformity of the lesser toes. It primarily comprises flexion deformity of the proximal interphalangeal (PIP) joint of the toe, with hyperextension of the metatarsophalangeal (MTP) and distal interphalangeal (DIP) joints (see Image 1). History of the ProcedureSurgical treatment of hammertoe deformity has historically been based on altering the relative lengths of the toe and its tendons. Options have included PIP joint resection arthroplasty, PIP joint fusion, tendon transfers, tendon lengthening, and metatarsal shortening. Metatarsal shortening has gained renewed interest, but PIP joint resection arthroplasty and tendon transfers are the main procedures for hammertoe correction. ProblemWith progressive PIP joint flexion deformity, compensatory hyperextension of the MTP and DIP joints typically occur. The hyperextension of the MTP joint and flexion of the PIP joint make the PIP joint prominent dorsally. This prominence rubs against the patient's shoe, causing pain. The deformity is flexible and passively correctable early in its natural history but typically becomes fixed with time. Progressive deformity can lead to MTP joint dislocation. FrequencyThe incidence of hammertoe deformity is undefined, but the condition is strongly associated with the presence of a second ray that is longer than the first. Indeed, this length disparity is found in most patients presenting with foot complaints, although the actual prevalence of this foot shape also is undefined. EtiologyEtiologies of hammertoe deformity include a foot in which the second ray is longer than the first (see Image 2), MTP synovitis and instability, inflammatory arthropathies, neuromuscular conditions, and ill-fitting shoe wear. MTP synovitis and instability are associated with a second ray that is longer than the first. Inflammatory arthropathies typically involve more than 1 of the lesser MTP joints. Ill-fitting shoe wear compounds the effects of any of the etiologies. PathophysiologyWhen a foot's second ray is longer than the first and shoe wear does not fit correctly, flexion of the PIP joint occurs to accommodate the shoe. This length difference also causes MTP synovitis to develop from overuse of the second MTP joint. Attenuation of the collateral ligaments and plantar plate result, and the MTP joint hyperextends and may even progress to dorsal subluxation or dislocation (see Image 3). Rheumatoid arthritis causes hammertoe deformity by progressive MTP joint destruction, leading to MTP joint subluxation and dislocation. With all 3 of these etiologies, the extensor digitorum longus (EDL) tendon gradually loses mechanical advantage at the PIP joint, as does the flexor digitorum longus (FDL) tendon at the MTP joint. The intrinsic muscles sublux dorsally as the MTP hyperextends. They now extend the MTP joint and flex the PIP joint, as opposed to their usual functions of flexing the MTP joint and extending the PIP joint. ClinicalThe patient with symptomatic hammertoe typically complains of pain over the dorsal aspect of the PIP joint. Occasionally, the patient also complains of pain over the plantar area of the metatarsal head, especially if the MTP joint is hyperextended, subluxed, or dislocated. A callus may be present over the dorsal surface of the PIP joint, over the plantar surface of the metatarsal head, or at the tip of the toe (see Image 4). In addition, patients with MTP instability often complain of pain over the dorsal part of the MTP joint, and they may describe the sensation of a lump in the plantar area of the MTP joint. The physical examination of hammertoe deformity must include a neurovascular evaluation, including palpation of pulses, a sensory examination, and an evaluation of intrinsic muscle bulk. The deformity should be assessed while the patient is standing, to appreciate its functional significance. Accompanying deformities, such as hallux valgus, combined hammertoe and rotational deformity, and cavus foot deformity, must be catalogued. Passive correction of the deformity should be attempted, because this will help determine which treatment options are appropriate for the patient. Palpate both the plantar and articular portions of the metatarsal head, because patients with MTP instability have greater tenderness of the articular portion and may require treatment different from that of patients with isolated hammertoe. Pain with dorsal subluxation of the MTP joint implicates MTP instability (see Image 5). Palpate the webspace and compress the forefoot by squeezing the metatarsals together from medial to lateral. These 2 maneuvers help to exclude an interdigital neuroma, which often is confused with MTP instability. INDICATIONSSection 3 of 12
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 is indicated at the time of hallux valgus correction, to minimize the likelihood of recurrent hammertoe. Flexibility of the deformity determines which technique is appropriate for correction. Passively correctable deformity is amenable to Girdlestone-Taylor flexor-to-extensor tendon transfer. Fixed deformity requires either PIP resection arthroplasty or partial proximal phalangectomy. Both flexible and fixed deformities also may require MTP arthroplasty and/or extensor tenotomy to achieve adequate correction. A rotational deformity may require the addition of derotational phalangeal osteotomy. A metatarsal shortening osteotomy may need to be added for a dislocated MTP joint or MTP instability with synovitis. Plantar condylectomy of the metatarsal head may need to be added for plantar metatarsal head pain without instability or synovitis. RELEVANT ANATOMYSection 4 of 12
The lesser toe comprises 3 phalanges that articulate at the proximal and DIP joints. The proximal phalanx articulates with the metatarsal at the MTP joint. Medial and lateral collateral ligaments, a fibrocartilaginous plantar plate, and a thin dorsal capsule stabilize each of the 3 joints. The EDL tendon originates in the leg and crosses the ankle anteriorly. Although it extends all 3 joints of the lesser toe, it primarily acts at the MTP joint. The extensor digitorum brevis originates in the sinus tarsi and blends with the EDL tendon over the proximal phalanx to form the extensor expansion. The EDL continues distally from the extensor expansion and trifurcates to form the central slip, which inserts onto the middle phalanx, and the lateral bands, which insert onto the distal phalanx. The central slip and lateral bands extend the PIP and DIP joints, respectively, when the MTP joint is in neutral position or in plantarflexion. The FDL tendon originates in the leg, crosses the ankle medially, and flexes all 3 joints, although it acts primarily at the DIP joint. The flexor digitorum brevis tendon originates from the plantar surface of the calcaneus and primarily flexes the PIP joint. The lumbricals originate from the medial and lateral surfaces of the metatarsals, pass plantarly to the MTP, and then extend dorsally to coalesce with the lateral bands. Thus, the lumbricals flex the MTP joint and extend the PIP and DIP joints. The neurovascular bundles of each toe arise from a common interdigital artery and interdigital nerve. Each bifurcates at approximately the level of the MTP joint. Each branch then extends along the medial and lateral aspects of the toe deep to the subcutaneous tissue. Both the interdigital artery and nerve are plantar to the intermetatarsal ligament at the level of the MTP joint. Both can become contracted in a chronic hammertoe and are subject to traction injury with hammertoe correction. CONTRAINDICATIONSSection 5 of 12
Contraindications for surgery include active infection, inadequate vascular supply, and the desire for cosmesis alone. The patient must understand that the goal of surgery is pain relief, not cosmesis. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Histologic FindingsHistologic evaluation is typically not available or necessary before hammertoe treatment. Skin ulceration and osteomyelitis may occur in neuropathic patients with hammertoe deformity. Histologic confirmation of osteomyelitis precludes most hammertoe reconstruction procedures. TREATMENTSection 7 of 12
Medical therapyThe choice of nonoperative treatment of hammertoe deformity is based on the flexibility of the deformity. Strapping of the toe with either tape or a commercially available hammertoe sling is helpful for a flexible deformity. 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 reduced. 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 1 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. While no reliably effective physical therapy program for hammertoe deformity has been described, it may be of use for the patient with a flexible deformity to perform passive stretching exercises. Surgical therapySurgical treatment of hammertoe deformity, like nonoperative treatment, depends on the flexibility of the deformity. The magnitude of the deformity also affects surgical decision making. A flexible deformity of small magnitude may be amenable to a flexor tenotomy. A small flexion deformity of the PIP joint should be present, with no subluxation of the MTP joint. Flexible deformity of greater magnitude requires a Girdlestone-Taylor flexor-to-extensor tendon transfer. 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. The goal is to shorten the toe and, thus, 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. PIP joint arthrodesis has been described and is currently performed with regularity. Cock-up deformity is a frequent complication, especially when significant MTP hyperextension is present preoperatively. Special consideration is necessary when hallux valgus accompanies second hammertoe deformity. Even if the hallux valgus and bunion are asymptomatic, hallux valgus correction is necessary to minimize the risk of recurrence of the second hammertoe. Metatarsal shortening procedures have begun to regain popularity. They are most likely to be effective in a foot with a long second metatarsal when second hammertoe is accompanied by pain and/or plantar callus over the second metatarsal head or when MTP instability and synovitis are present. It may be necessary to combine other procedures (PIP resection arthroplasty, Girdlestone-Taylor flexor-to-extensor tendon transfer) with the metatarsal shortening, to achieve adequate correction. When rotational deformity accompanies hammertoe deformity, rotational or angulatory deformity of the involved phalanx may be necessary. Preoperative detailsPreoperative evaluation includes an assessment of circulation, sensation, flexibility and magnitude of the deformity; associated deformities; and metatarsalgia. Palpable pulses indicate an excellent prognosis for healing. Doppler studies should be obtained if pulses are not palpable. An ankle-brachial index greater than 0.65 and/or toe pressure greater than 40 also indicate a good prognosis for healing. A severe, long-standing, fixed hammertoe deformity can become ischemic when corrected, because of traction on the digital arteries caused by straightening the toe. Traction on the digital nerves can result in neuropraxia; 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. The flexibility and magnitude of the deformity determine the surgical treatment. 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. Intraoperative detailsFlexor tenotomy Flexor tenotomy is typically performed via a plantar stab incision at the 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 (K) wire then is 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. 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. 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 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 interphalangeal 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 with 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 and/or MTP joint is necessary. 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 by 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 then is placed in an antegrade manner through the middle and distal phalanges while DIP joint extension is maintained. It is then placed in retrograde fashion into the proximal phalanx while PIP joint extension and distraction are maintained. The skin, tendon, and capsule then are closed together as a single layer. 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 EDL and extensor digitorum brevis 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 is performed. The Weil osteotomy is an effective metatarsal shortening method. 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 was weightbearing. The metatarsal is translated proximally about 3-4 mm, and screw fixation is placed. The redundant dorsal cortex is then removed. 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. Postoperative detailsThe pin is cut to length outside the skin. 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. Follow-upWeightbearing, 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 wk 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 interphalangeal joints. Because some stiffness is intentional to maintain 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. COMPLICATIONSSection 8 of 12
Complications of hammertoe correction surgery include infection, delayed wound healing, recurrent deformity, molding, loss of fixation, neurovascular injury, and 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 antibiotics to which typical skin flora are sensitive. Deep infection often requires irrigation and debridement. 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, as described in Treatment, Medical therapy, and a second piece should be added to maintain extension of the interphalangeal 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 the patient's treatment are vigilant follow-up care, debridement when necessary, local wound care, and therapy with oral antibiotics to which typical skin flora are sensitive. 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. 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 neuropraxia, vasospasm, or digital artery avulsion. Ischemia rarely results because of the collateral circulation. 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, in that way reducing tension on the neurovascular bundle. The pin may need 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. OUTCOME AND PROGNOSISSection 9 of 12
Patients should be counseled that their expectation for a good result after hammertoe treatment is permanent relief of pain and an ability to wear reasonable shoes (those of appropriate length, width, and depth for their entire foot) without pain. Nonoperative treatment of hammertoe deformity often successfully alleviates pain; however, the deformity typically progresses in magnitude and stiffness in most cases in spite of diligent nonoperative care. Surgical treatment of flexible hammertoe deformity reliably corrects the deformity and alleviates pain. Recurrence and progression are common, especially if the patient resumes wearing deforming shoes. Surgical treatment of fixed hammertoe deformity provides very reliable deformity correction and pain relief. Recurrence is rare. FUTURE AND CONTROVERSIESSection 10 of 12
Metatarsal-shortening procedures have become more popular as adjuncts to hammertoe correction in recent years but have not yet been widely accepted. Choices include traditional diaphyseal shortening or 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 MTP arthroplasty and plantar condylectomy. MTP arthroplasty includes resection of 2 mm of the metatarsal head articular surface and pinning of the toe across the MTP joint. The resulting arthrofibrosis is theorized to stabilize the MTP joint. 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 re-adheres and contracts to stabilize the MTP joint. 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. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Article Last Updated: Mar 15, 2007 | |||||||||||||||||||||||||||||||||||||||||||||||
