Current Insights On The Use Of Orthotics For Limb Length Discrepancy And Morton’s Syndrome

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Identifying Structural Deficiencies In Pathomechanical Foot And Limb Function That May Contribute To Knee Disorders

Q: What is the role of pathomechanical foot and limb function in knee disorders and how can identification of inherent structural deficiencies prevent these repetitive stress problems from producing degenerative changes later in life?

A: Dr. D’Amico and Dr. Skliar concur that the increased demands of high school sports on young adolescents have resulted in an epidemic of knee injuries.

Dr. Skliar notes several such injuries in decreasing order of frequency: patella and medial knee pain, Achilles tendonitis and calf pain, shin splints and groin pain. Athletes who display greater than 6 degrees of total frontal plane varus compensations make up the largest group of those who seek professional care, points out Dr. Skliar. He says anyone with 10 degrees or higher of total varus should receive biomechanical treatment even if they are asymptomatic.

“Improper athletic shoes for the various sport activities and for different foot types can significantly aggravate or cause excessive stresses to the limbs,” notes Dr. Skliar.

Dr. Skliar suggests providing professional information concerning proper footgear for the individuals involved in a specific sport. He also says there needs to be better recognition of how the foot structure of each athlete can influence how well suited the athlete may be to a specific sport activity. As Dr. Skliar explains, feet with normally low arch structures are usually more stable due to the larger weightbearing surface they present. Those who possess a normally high arch foot are less stable in static conditions but he notes they have a mechanical advantage for speed and jumping activities. Accordingly, Dr. Skliar says a lineman of a football team would fare better with a normal low arch foot while the running back would do better with a high arch foot type.

As Dr. D’Amico says, triplanar compensation associated with any condition producing excessive pronation is not matched to the primarily sagittal plane motion at the knee joint. As a result, he notes the frontal and transverse plane demands are taking place while the foot is planted against an unyielding surface, and the superstructure is moving forward over the supporting extremity. Among other things, he says this increases medial collateral ligament stress and strain as well as the Q angle.

Schuster postulated a mechanism between pedal pronation and the production of knee pain, and recommended treating the underlying pathology via foot orthoses, according to Dr. D’Amico.1 In that article, the author goes on to say, “it is noteworthy that almost every runner we have had the opportunity to treat on a mechanical basis has had a moderate to severe forefoot varus.” Over 20 years later, Dr. D’Amico says Saxena and Haddad went on to confirm this statement in a study of 102 patients with patellofemoral pain syndrome in which they found 91 percent of patients to have had forefoot varus.2

Dr. D’Amico says the research has highly correlated malalignment of the patellofemoral mechanism with excessive pronation.3-5 He adds that an increase in the Q angle has direct correlation of knee pathology especially of mechanical origins.6

“The role of the podiatrist is to identify and neutralize structural deficiencies present in the foot, especially forefoot varus, thereby preventing dysfunction and at the same time reducing the risk of injury,” says Dr. D’Amico.

The “missing link” in all sports at any level is structural evaluation prior to training an athlete, contends Dr. Pack, who treats athletes who have $125 million contracts but have never been evaluated. As he notes, pathomechanical foot and limb function are a major cause of not just knee injuries but many other injuries. For example, Dr. Pack says for an ankle sprain, physicians readily accept the fact that a hard hit in football may be the cause but if the injured individual gets a proper evaluation, a rearfoot varus deformity, equinus of the first metatarsal or other abnormality may often be the underlying etiology.

Dr. Pack says children should have a basic structural screening by a podiatrist. “Doing so would not only greatly decrease injuries but increase sports performance and later decrease arthritic changes,” notes Dr. Pack.

References

1. Schuster RO. Podiatry and the foot of the athlete. J Am Podiatr Assoc. 1972; 62(12):465-8.
2. Saxena A, Haddad J. The effect of foot orthoses on patellofemoral pain syndrome. J Am Podiatr Med Assoc. 2003; 93(4):263-71.
3. James SL, Bates BT, Osternig LR. Injuries to runners. Am J Sports Med. 1978; 6(2):40-50.
4. Jernick S, Heiflitz NM. An investigation into the relationship of foot pronation to patellofemoral pain syndrome. In Rinaldi RR, Sabia ML (eds.) Sports Medicine ‘79. Futura Publishing Company, Mt. Kisco, New York, 1979, pp. 1-31.
5. Eng JJ, Pierrynowki MR. The treatment of patellofemoral pain syndrome. Phys Ther. 1993; 73(2):62-68.
6. Emami MJ, Glaahramani MH, Abdinejad F, Namazi H. The Q angle: an invaluable parameter for the evaluation of anterior knee pain. Arch Iran Med. 2007; 10(1):24-26.

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Author(s): 
Guest Clinical Editor: Joseph C. D’Amico, DPM, DABPO

   Calling Morton’s syndrome “a very insightful concept of forefoot hypermobility and subsequent excessive pronation,” Dr. Skliar says Morton described three osseous foot abnormalities that are visible on a dorsal-plantar X-ray of a foot that exhibited biomechanical problems.2 They are, in descending frequency: a short first metatarsal; hypermobility of the first segment (i.e. a cleft between the metatarsal base and the internal cuneiform with the base of the second metatarsal bone); and a posterior placement of the first metatarsal sesamoids. As Dr. Skliar explains, any of these three findings could present alone or in any two combinations, or all three could present together.

   Dr. Skliar notes that Morton’s syndrome almost always results in a hypertrophy of the mass of the second metatarsal and/or sometimes a relative flattening of the second metatarsal head, or lateral bowing of the fifth metatarsal. In more advanced cases, he notes there can be a possible lowering of the navicular, a positive Helbing’s sign of the tendo-Achilles, abduction of the forefoot or internal limb rotation.

   What Morton described is what podiatric physicians now recognize as a partial or complete compensation for what Root described as a forefoot varus and/or equinovarus, notes Dr. Skliar.3 However, he notes Morton attributed the underlying mechanism to “ligamentous laxity” acting on the sagittal plane rather than recognizing that it is a frontal plane problem. Compensation occurs at the rearfoot at the subtalar joint and involves the other two planes.

   For Morton’s syndrome, Dr. Skliar suggests conservative management with rigid orthotics from the heel to metatarsal head. He advises posting at the heel and forefoot to accommodate the total varus influences of the forefoot, rearfoot and limb.

   Dr. Pack sees Morton’s syndrome quite often as a contributing symptomatic factor in the adult patient population. He usually finds that incorporating a metatarsal pad or bar into a custom foot orthotic can treat the problem quite easily.

   “The significance and incidence of Morton’s syndrome has been underemphasized as a major contributing factor in the production of pathologic foot function and subsequent deformity,” says Dr. D’Amico. “The presence of this deformity in any of the pathologic foot types only adds to the severity of dysfunction and deformity potential that is taking place.”

   Dr. D’Amico notes that identifying this entity is relatively simple and one can address it by adding a Morton’s extension to the first metatarsal segment. As he notes, this restores a normal metatarsal parabola and the potential for improved function, providing one has identified and neutralized any accompanying structural deficiencies as well.

   Dr. D’Amico is a Professor and Past Chairman in the Division of Orthopedics at the New York College of Podiatric Medicine. He is a Diplomate of the American Board of Podiatric Medicine, and a Fellow of the American Academy of Foot and Ankle Pediatrics. Dr. D’Amico is in private practice in New York City.

   Dr. Pack is a Fellow of the American College of Foot and Ankle Surgeons and a Diplomate of the American Board of Podiatric Surgery. He is a Founding Fellow of the American College of Rheumatology and a Fellow of the Academy of Ambulatory Foot and Ankle Surgeons. He is in private practice in Georgia. Dr. Pack is a former Clinical Instructor of Medicine at Emory Medical School and a Consultant to the U.S. Navy SEALs.

   Dr. Skliar recently retired from practice. He is a Fellow and Past President of the American College of Foot and Ankle Orthopedics and Medicine. He is a Professor Emeritus of the New York College of Podiatric Medicine and an Assistant Professor in the Division of Orthopedics at Barry University.

References
1. Schuster RO. Survey analysis of the Morton syndrome. J Natl Assoc Chirop. 1952; 42(5):35-41.
2. Morton D. The Human Foot, Hafner Publishing Co., 1964.
3. Root ML. Normal and Abnormal Function of the Foot, vol. 2. Clinical Biomechanics Corp., 1977, p. 298.

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