Kohler Disease (Aseptic Necrosis of the Tarsal Navicular)
Kevin E. Burroughs
BasicsDescription
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Osteochondrosis of the tarsal navicular, 1st described by Alban Kohler in 1908 (1)
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Osteochondrosis is a disease process that causes necrosis of the ossification center of a developing bone and is followed by regeneration.
Epidemiology
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Predominant age: Occurs in children 2–7 yrs of age (average age 5 yrs and 10 mos)
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Predominant gender: Males > Females (4–6:1)
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Usually occurs unilaterally; bilateral in only ∼15–20% of cases.
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Appears to be no relation between weight and incidence.
Risk Factors
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May be caused by repetitive microtrauma to the maturing navicular ossification center
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Compression of the bony nucleus at a critical phase of growth may occlude the penetrating blood vessels and produce ischemia and aseptic necrosis of the bone.
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Delayed ossification leading to irregular ossification centers may predispose to this condition.
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Occurrence is not related to acute macrotrauma, age at 1st walking, foot type, or family history.
Etiology
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Navicular development:
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The navicular becomes evident on radiographs between 18 and 24 mos in girls and between 30 and 36 mos in boys.
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A more irregular and more dense navicular is often present in children whose navicular ossifies at later times than these, and these findings are similar to those in Kohler disease.
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The navicular ossifies from a single center in 2/3 of children and from multiple centers in the remainder. Those ossifying later than the norm tend to be from multiple centers.
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A dense perichondral network of blood vessels has been described on the nonarticular surfaces, with numerous penetrating arteries.
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Theories of etiology:
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Questionably a normal variant but does not explain why some individuals are asymptomatic.
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Some believe that it is avascular necrosis. However, this wouldn't explain acute onset of pain, lack of correlation with radiographic changes in the short amount of time, and no matter the treatment, a normal navicular is the end result (true necrosis should cause deformity).
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Most likely a syndrome or continuum of disease because radiographic changes can be seen in asymptomatic individuals. Perhaps those who are symptomatic have experienced a stress injury to the ossifying bone. This would explain radiographic changes, with remodeling to a normal-appearing bone.
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DiagnosisAlthough variations in morphology of the navicular have been described, the diagnosis of Kohler disease is made on the basis of both clinical and radiographic findings.
History
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It is often difficult for young children to localize pain, but it should be over the midfoot area.
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Repetitive microtrauma may be a risk factor in sport activities.
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A history of macrotrauma should lead the practitioner to consider other causes of foot pain.
Physical Exam
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Signs and symptoms:
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Insidious onset of foot pain and limp aggravated by activity
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Time to presentation varies from days to months after onset of pain.
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Physical examination:
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Look for localized edema and warmth in the area of the tarsal navicular.
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Palpate the entire foot and ankle; tenderness should be localized to the medial midfoot.
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Check the range of motion of the ankle and subtalar joints, which should be normal.
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Examine the knee and hip, which can be the source of referred pain and limp.
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Diagnostic Tests & Interpretation
Imaging
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Radiographs: Standard anteroposterior, lateral, and oblique radiographs of the foot should be obtained.
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Findings:
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Varying degrees of navicular sclerosis
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Diminished size or flattening of the navicular (“Alka-Seltzer-on-end” appearance)
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Occasional loss of trabecular pattern and fragmentation
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A person with an asymptomatic foot with abnormal radiographic features found incidentally does not have Kohler disease.
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Bone scintigraphy: Not recommended but will show decreased uptake in the navicular indicating decreased or interrupted blood supply.
Pathological Findings
Patchy areas of bone destruction and dead trabeculae with interference of normal ossification
Differential Diagnosis
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Normal variants: Variations of size and shape of the navicular ossification center may be indistinguishable from Kohler disease except for the absence of symptoms.
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Osteochondritis dissecans
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Localized involvement on the articular surface
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Well demarcated from the normal bone by a crescent-shaped area of radiolucency
P.347
Treatment-
Acute treatment:
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Apply ice to midfoot.
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NSAIDs or acetaminophen can be used for analgesic effect.
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Immobilization to effect relief of symptoms, although the type and duration of treatment do not influence long-term outcomes.
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Immobilization:
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Despite not altering the long-term outcome, immobilization has been shown to decrease the duration of symptoms.
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Patients with cast immobilization are typically pain-free at 3 mos, whereas those treated without casting were symptomatic until 15 mos on average.
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Those casted for at minimum 2 mos were asymptomatic in the shortest time.
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Weight-bearing status does not appear to affect outcome.
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Additional Treatment
Additional Therapies
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Orthoses have not been found to be effective.
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Rehabilitation: Usually not indicated
Surgery/Other Procedures
Rarely required
Ongoing CareFollow-Up Recommendations
Orthopedic referral is indicated if symptoms do not resolve with conservative management.
Patient Monitoring
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In a study of 12 cases, complete restoration of normal bone structure occurred in 8 mos (minimum 6 mos and maximum of 13 mos).
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At 30-yr follow-up, no patient showed degenerative changes at the tarsonavicular joint, and no radiographic differences were seen with the unaffected foot.
Prognosis
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Complete resolution of symptoms with reconstitution of the navicular can be expected in all patients.
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No evidence of cartilage degeneration in long-term follow-up studies
Reference
1. Kohler A. A frequent disease of individual bones in children. Munch Med Wochenschr. 1908;55:1923–1925.
Additional Reading
Borges JL, Guille JT, Bowen JR. Köhler's bone disease of the tarsal navicular. J Pediatr Orthop. 1995;15:596–598.
Gips S, Ruchman RB, Groshar D. Bone imaging in Kohler's disease. Clin Nucl Med. 1997;22:636–637.
Ippolito E, Ricciardi Pollini PT, Falez' F. Köhler's disease of the tarsal navicular: long-term follow-up of 12 cases. J Pediatr Orthop. 1984;4:416–417.
Manusov EG, Lillegard WA, Raspa RF, et al. Evaluation of pediatric foot problems: the forefoot. Am Family Physician. 1996;54:592–606.
Sharp RJ, Calder JD, Saxby TS. Osteochondritis of the navicular: a case report. Foot Ankle Int. 2003;24:509–513.
Stanton BK, Karlin JM, Scurran BL. Köhler's disease. J Am Podiatr Med Assoc. 1992;82:625–629.
Williams GA, Cowell HR. Köhler's disease of the tarsal navicular. Clin Orthop Relat Res. 1981:53–58.
CodesICD9
732.5 Juvenile osteochondrosis of foot
Clinical Pearls
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Although all patients eventually will have complete resolution of symptoms, immobilization with a cast for at least 8 wks shortens the duration of symptoms by ∼1 yr.
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Sports may be resumed once symptoms have resolved.
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Long-term follow-up studies have found no increase in the rate of arthritis or other chronic foot problems in adults who had Kohler disease during childhood.