You are in: eMedicine Specialties > Orthopedic Surgery > FOOT AND ANKLE Intractable Plantar KeratosisArticle Last Updated: Feb 9, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Gregory C Berlet, MD, FRCS(C), Clinical Assistant Professor of Orthopedics, Chief of Foot and Ankle Surgery, Department of Orthopedic Surgery, Ohio State University College of Medicine and Public Health, Fellowship Director of Orthopedic Foot and Ankle Center Gregory C Berlet is a member of the following medical societies: American Medical Association, American Orthopaedic Foot and Ankle Society, Canadian Medical Association, Canadian Orthopaedic Association, College of Physicians and Surgeons of Ontario, Ontario Medical Association, and Royal College of Physicians and Surgeons of Canada Coauthor(s): Christopher Hyer, DPM, Advanced Podiatric Surgery Fellowship Director, Foot and Ankle Surgery, Orthopedic Foot and Ankle Center; Noah S Scheinfeld, MD, JD, FAAD, Assistant Clinical Professor, Department of Dermatology, Columbia University; Consulting Staff, Department of Dermatology, New York Medical College-Metropolitan Hospital; Private Practice; Mark Loebenberg, MD, FAAOS, Consulting Staff, Department of Orthopedic Surgery, Assaf HaRofeh Medical Center 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: IPK, foot callus, diffuse intractable plantar keratosis, diffuse IPK, tyloma INTRODUCTIONSection 2 of 11
  Intractable plantar keratosis (IPK) is a discrete, focused callus, usually about 1 cm, on the plantar aspect of the forefoot. Typically, IPKs occur beneath one or more lateral metatarsal heads or under another area of pressure (Mann, 1987). History of the ProcedureIPKs are often treated successfully with nonoperative care. Those lesions that continue to cause pain may require surgical intervention. Various surgical procedures have been described for treatment of IPK, ranging from partial metatarsal excisions to metatarsal osteotomies and shortening procedures or, in the case of the first ray, sesamoid surgery. Henri DuVries, MD, reported on metacondylectomy in 1953. This technique involves removal of a portion of articular surface of the metatarsal and the plantar condyle. The procedure completely resolved the lesion in 79% of patients and was associated with a 93% patient satisfaction rate (Mann and DuVries, 1973). Hatcher and colleagues (1978) presented a thorough review of 238 various metatarsal osteotomies used in the correction of IPK. The overall success rate was only 56.5%; this was thought to be due to the fact that transfer lesions occurred in almost 40% of the patients (Hatcher et al, 1978). Several different distal osteotomies are described, including the dorsal V (or chevron) osteotomy, the tilt-up wedge osteotomy, and the free-floating osteoclasis technique. The chevron osteotomy of the distal metatarsal, with dorsal displacement of metatarsal head, is frequently reported. Dreeben and colleagues (1989) found complete relief of symptoms in 67% of 45 patients in whom this method was used. Young and Hugar (1980) likewise used the chevron osteotomy, and achieved an 87.5% success rate in resolving symptomatic IPK. A more recent modification of the DuVries technique is to remove just the plantar condyle, through a dorsal approach. This significantly reduces the chance of transfer lesions, because no change is made to the weightbearing metatarsal parabola. An isolated IPK beneath the first metatarsal is often caused by a hypertrophic sesamoid bone. Historically, this was treated with tibial or fibular sesamoidectomy. Sesamoid shaving or planing has met with good success and fewer complications (Mann and Wapner, 1992). ProblemThe IPK is a focused, painful lesion directly beneath a weightbearing portion of the foot. This pain can limit ambulation and also cause compensatory changes in gait. FrequencyIPK is not uncommon, but its exact frequency requires further definition. EtiologyA focused area of pressure on the plantar fat pad, typically resulting from a dropped, or, more correctly, plantarflexed, metatarsal, causes IPK. In such cases, the metatarsal head lies in a plane lower than the surrounding metatarsals, focusing exaggerated weightbearing stress on this area. Other causes of IPK include tight or poorly fitting shoes, hammertoe deformity, long lesser metatarsals, hypertrophic plantar metatarsal head condyles, malunion of metatarsal fracture, accessory sesamoids, and first-ray hypermobility. In poorly fitting shoes, the toes may become buckled in a tight toe box and create a retrograde hammertoe affect. This forces the toe on top of the lesser metatarsal head and drives the head down against the plantar fat pad. Long lesser metatarsals also have added weightbearing stress shifted to them, potentially causing an IPK. A hypermobile first ray shifts weightbearing stress laterally and potentially overloads the plantar fat pad. An IPK beneath the first metatarsal head is often caused by hypertrophy of either the fibular or tibial sesamoid. Other possible causes include a plantarflexed first ray, a hammered great toe, a cavus foot deformity, or excessive pronation. PathophysiologyThe pathophysiology of intractable plantar keratoses involves an impairment of normal weightbearing and a resultant increase in the thickness of the stratum corneum of the sole of the foot. As the lesion develops, the central portion invaginates and becomes extremely painful. ClinicalThe patient reports pain in the plantar aspect of the forefoot, which is aggravated by weightbearing; pain is exacerbated when the individual is barefoot. Patients often report a sensation similar to walking on a marble. Most have had this lesion for many years and have tried various home remedies. Sometimes, patients provide a confusing history of a possible foreign-body lesion or of having warts. On physical examination, the IPK typically appears in 1 of 2 presentations. A focused, discrete IPK is more common and seen directly overlying a bony prominence. This lesion is approximately 1 cm, with a hyperkeratotic rim and a painful, white center core. There is rarely any erythema, edema, or suspicion of infection. This lesion occurs as an isolated IPK or as several discrete, isolated IPKs. Another type of presentation is a more diffuse buildup of keratotic tissue, called a diffuse IPK or tyloma. This frequently is seen spanning across the plantar aspect of several metatarsal heads and does not have the focused central core. INDICATIONSSection 3 of 11
The indications for surgical treatment of IPK include the following:
RELEVANT ANATOMYSection 4 of 11
When plantar or dorsally displaced, a metatarsal alters the pressure pattern in the forefoot, and an IPK can form in the area of increased pressure. Typically, this is beneath one of the lesser metatarsal heads and can be exacerbated by a hammertoe deformity or hypertrophic metatarsal condyles. These condyles are small protuberances on the plantar flare of the metatarsal head that serve as a soft-tissue attachment point. In some cases, these condyles become enlarged and cause focused pressure beneath the metatarsal head. IPKs beneath the great toe are somewhat different. Beneath the first metatarsophalangeal (MTP) joint are 2 small bones called sesamoids, embedded within the soft tissues. The toe flexors pass underneath the first MTP joint, and the sesamoids act as a fulcrum, similar to the patella in the knee. The sesamoids also help to absorb pressure under the foot during standing and walking, and they ease friction in the soft tissues under the toe joint when the big toe moves. Malalignment of or a fracture in the sesamoids can contribute to the development of IPK. Consider the metatarsal parabola, or cascade, when considering surgical intervention. In the typical cascade, the second digit is longer than (or sometimes as long as) the first, followed in length by, from longest to shortest, the third, fourth, and fifth digits. This permits the natural transition of weightbearing forces across the forefoot. If this cascade is altered, either in metatarsal length or in the metatarsal head position in the sagittal plane, this can create an IPK. CONTRAINDICATIONSSection 5 of 11
Absolute contraindications include local infection, vascular insufficiency, painless lesion, and neuropathy. Relative contraindications include diabetes, avascular necrosis (AVN) of the metatarsal head, or hypermobile first ray. WORKUPSection 6 of 11
Lab Studies
Imaging Studies
Other Tests
Histologic FindingsA biopsy of IPK shows hyperkeratosis and inflammation. TREATMENTSection 7 of 11
Medical therapyFirst-line medical treatment of IPK includes the following:
More effective and invasive treatments include debridement. Surgical therapySurgical treatment of IPK can involve the following:
Preoperative detailsDetailed history, meticulous clinical assessment, and radiographic evaluation should be used to assess the causes and extent of IPK. Lesions recalcitrant to nonoperative care and routine debridement can be considered for surgery. Patients should be appropriately counseled on the risks and benefits of surgery and the expected postoperative course. Operative risks include infection, neurovascular damage, nonunion, wound dehiscence, toe destabilization, recurrence of lesion, and development of a transfer lesion. The patient should be made aware of the likelihood of recurrence or transfer lesion development. The patient must have appropriate expectations. An informed surgical consent is obtained. The clinician must determine the cause of the IPK because this dictates the surgical correction. Associated pathologies, such as hammertoe contracture, should be addressed at the same sitting if they are causative to the painful IPK. Intraoperative detailsAgain, there are various surgical approaches to the correction of an IPK. The authors' preferred technique includes either the plantar condylectomy of the metatarsal head or a double-cut Weil oblique osteotomy of the metatarsal head. Either surgery is well suited to monitored anesthesia care (MAC) with a regional popliteal or ankle block. An ankle Esmarch or tourniquet can be used as long as this does not cause contracture of the long toe flexors. A dorsally based linear incision is marked just medial or lateral to the extensor tendon over the involved MTP joint. Sharp dissection through the skin and fascia tissue is performed, with care taken to protect any cutaneous nerves. The incision is deepened, and the extensor complex is elevated and protected either medially or laterally. The capsular tissue is sharply incised, and minimal release of the collaterals is performed to enhance exposure. The involved toe is plantarflexed to expose the metatarsal head. If a plantar condylectomy is to be performed, the plantar capsular attachments must be released with a blade. Care should be taken to protect the long flexor tendons beneath the metatarsal head. The plantar condyles are identified, and one is typically larger than the other. A microsagittal saw is used to remove the condyles in a thin plantar osteotomy made parallel to the weightbearing surface (plantar one-third of the metatarsal head). The small sliver of bone, including the condyles, is then removed. A hand rasp can be used to smooth any rough edges. A percutaneous Kirschner (K) wire is driven through the length of the toe and across the involved MTP joint down the metatarsal. This is important to allow the plantar capsule to adhere to the cut bone surface and prevent MTP destabilization. If the involved metatarsal is plantarflexed or elongated, a double-cut Weil osteotomy is instead performed. The microsagittal saw is used to make a 30° osteotomy at the superior aspect of the metatarsal head-neck junction angled from distal-dorsal to proximal-plantar. Two blades are stacked together to create a controlled wedge resection. The width of each blade cut is approximately 1 mm, so 2 blades together create a 2-mm wedge. This allows some dorsal displacement of the metatarsal head in a controlled fashion. The metatarsal head is also translated slightly proximal along the osteotomy to shift the head away from the pressure area, and it is fixated with a small screw. An aggressive proximal shift must not be made, because this can shift the head in a plantar direction as it follows the angle of the osteotomy. Again, a percutaneous K-wire is used to splint the toe and maintain alignment of the MTP joint. The extensor tendon sling and capsular tissue is repaired with 2-0 absorbable suture. Subcutaneous closure is performed with 2-0 absorbable suture, and skin is closed with 4-0 nonabsorbable suture of choice. The IPK is then debrided from the plantar forefoot, and the central core should be completely removed. A compressive dressing is applied, and the tourniquet is released. Before leaving the operating room, the physician should confirm that the toe's vascularity is intact. Postoperative detailsThe patient is placed in a rigid postoperative shoe and allowed to bear weight on the heel to tolerance. The dressing is kept clean and dry and is changed in 7-10 days. At that point, the sutures are removed if adequate healing has taken place. Postoperative radiography is performed to confirm alignment of the toe and/or osteotomy. The patient must remain in the postoperative shoe until the K-wire is removed and adequate healing of the osteotomy is observed. Typically, the K-wire is left in place for 4 weeks and then removed in the office. At 6 weeks postoperatively, follow-up radiography is performed to assess the healing of the osteotomy. The osteotomy typically requires 6-8 weeks to heal enough to allow migration out of the surgical shoe and into a comfort shoe. Once the patient is in a comfort shoe, postoperative exercises of the toe are encouraged, to restrengthen the toe and prevent loss of purchase, or floating, of the toe. Typically, patients are able to return to all activities without restriction by 12 weeks. Follow-upAppropriate shoe wear is important in preventing recurrence of the IPK. The patient should again be counseled on wearing shoes with enough room in the toe box and a reasonable heel height. Custom orthotics may be beneficial in supporting the foot, and specific modifications can be made to off-load the surgical area. Periodic follow-up should be made to monitor for recurrence of the IPK or development of transfer lesions. Patient education For excellent patient education materials, see eMedicine's Foot, Ankle, Knee, and Hip Center. COMPLICATIONSSection 8 of 11
Postoperative complications of surgery for IPK include the following:
OUTCOME AND PROGNOSISSection 9 of 11
A successful outcome is based on accurately identifying the etiology of the IPK and clearly establishing realistic expectations. If the underlying cause is not addressed, the outcome will be poor and the patient unhappy. Conservative, nonoperative treatments should not be discounted and often are all that are required for patient relief. A study by Kang and colleagues (2006) found that the use of metatarsal off-loading pads reduced peak pressures and improved subjective pain responses in patients. In 1992, Mann and Wapner reported on tibial sesamoid shaving in 10 patients with symptomatic IPK below the first metatarsal. At an average follow-up of 52.6 months, 9 of the 10 patients reported good to excellent results, and 1 described results as fair. For the more typical lesser-metatarsal IPK, one of the various metatarsal procedures may be used. The difficulty with the majority of the metatarsal osteotomies is the unpredictable degree of dorsal displacement. Intraoperatively, it is difficult to accurately gauge the level of the metatarsal heads in the sagittal plane. The use of internal fixation reduces the chance that weightbearing will cause unwanted dorsal displacement. In 2000, Kiviniemi and colleagues treated 25 plantar callosities in 13 patients (mean age 48 y; 5 male, 8 female) with transverse distal metatarsal osteotomy. Osteotomies united primarily in 24 cases, 1 after revision. Twenty-three of the callosities healed, 2 of them after an oblique reosteotomy; follow-up extended 7 years. In 4 of the treated feet, 8 hammertoe deformities developed in the involved rays. In 5 of the feet, 8 plantar callosities developed outside the operated rays. The distal chevron is reported in multiple studies. In 1998, Kitaoka and Patzer reviewed 21 feet that had undergone chevron osteotomy on the lesser metatarsals; the mean follow-up period was 4 years. Sixteen feet were labeled as good, 2 as fair, and 3 as poor. Transfer metatarsalgia occurred in 3 feet (14%). In a 1998 investigation of 20 patients with IPK, Idusuyi and colleagues found that although the single oblique lesser-metatarsal osteotomy may be successful, 50% of the patients studied continued to have some degree of pain, and most patients had limitations in footwear. A study by Grimes and Coughlin (2006) on the Weil osteotomy concluded that a proximal shift of the distal osteotomy may also shift in a plantar direction. They recommended that if a shift of greater than 5-mm is needed, a 2-mm-thick blade be used to allow for some dorsal displacement, in order to prevent plantar pressures. Another study on the clinical results of the Weil osteotomy found relief of plantar pain in 97% of patients treated, at a follow-up of 26 months (Kennedy and Deland, 2006). Proximal metatarsal segmental resection involves resection of a cylindrical segment of proximal metatarsal bone approximately 0.5 cm long. In 1990, Spence and colleagues reported good results in 54 patients operated on with this procedure. Overall, surgical intervention for lesser-metatarsal IPK should be undertaken with caution. In 1998, Pontious and colleagues reviewed 29 patients who altogether had undergone 40 V-shaped osteotomies for IPK. The overall effectiveness was quite limited, and there were multiple complications. Over 42% of the patients developed transfer lesions, 10% had recurrence, and 25% reported lack of toe purchase. FUTURE AND CONTROVERSIESSection 10 of 11
The future of IPK treatment needs to focus on more accurately identifying the underlying pathology of IPK. The enhancement of nonsurgical means of treatment and the refinement of surgical options also are critical. Computerized force plates can aid in understanding the pressure distribution on the foot and thus create better off-loading orthotics. The high rate of transfer metatarsalgia and recurrence of IPK suggests that surgical intervention be undertaken with caution. Surgery is more successful when a specific etiology can be determined. The idea of prophylactic surgery on an asymptomatic foot based on irregularities seen on radiography is highly controversial and not recommended. REFERENCESSection 11 of 11
Intractable Plantar Keratosis excerpt Article Last Updated: Feb 9, 2007 |
