Fig. 3.1
Lateral radiograph displaying pediatric pes planus
In rigid pes planus, the range of motion is decreased at the tarsal and subtalar joints. The arch does not rise with toe rising. Possible causes include a tarsal coalition and peroneal spasticity. Flexible pes planus is physiologic or pathologic, depending on ligamentous laxity, motor weakness in the foot muscles, or bone abnormalities. These can be categorized further into three types.
Functional fiat foot (calcaneovalgus) is the most common type of flat foot with athletes. It is physiologic with a decreased longitudinal arch associated with heel eversion (calcaneovalgus). It is usually not painful or cause of disability in the athlete. Treatment usually consists of adequate heel counter support and orthotic therapy.
Hypermobile flat foot is associated with ligamentous laxity with tight heel chords. Possible causes include tarsal coalition, vertical talus, or accessory navicular. Treatment focuses on stretching exercises for the Achilles tendon and orthotic therapy.
Pes planus with posterior tibial tendon dysfunction evolves through a series of three stages , so it is imperative to recognize and treat this type early and aggressive. In stage 1, the posterior tibial tendon is normal length with the tendon showing degenerative changes. Typically there is mild-to-moderate pain along the posterior tibial tendon. Classically, the pain is localized a few centimeters distal to the tip of the medial malleolus, coursing along to the plantar attachment to the navicular bone. A single heel rise may reveal mild-to-moderate weakness of the tendon. Treatment is conservative with modifying the activity and using orthotic therapy. In stage 2, the posterior tibial tendon elongates, with the rearfoot becoming more mobile. Pain can be along the length of the tendon. The forefoot becomes abducted on the rearfoot, so if viewed from behind “too many toes” are observed. A single heel raise can show significant weakness. Treatment usually requires surgical consideration following an MRI evaluation. In stage 3, there is posterior tibial tendon rupture. The rearfoot becomes rigid and a fixed rigid flatfoot develops. This deformity is a dramatic presentation . A surgical arthrodesis can be required due to the severe pain with this progression.
Pes cavus is a high-arched foot with an elevation of the longitudinal arch, which is present with and without weight bearing. The toes can be contracted in the more severe cases. Characteristics include decreased pronation, rigid foot, weight unevenly distributed, and a tendency for later ankle instability leading to frequent inversion ankle sprains. There is limited range of motion and poor shock absorption. In the athlete, the cavus foot is usually a static idiopathic presentation. Neuromuscular causes are progressive in nature. Pes cavus can be congenital or functional in nature. Congenital causes include plantar flexed first ray, peroneal spasm/weakness, and metatarsus adductus. Functional causes include leg length difference, uncompensated rearfoot varus, partially compensated rearfoot varus, or compensated rigid forefoot valgus. Treatment consists of shoes with cushioning, orthotics for support, and stretching exercises of the plantar fascia and Achilles tendon.
Functional Foot Disorders
Functional foot disorders can be in the frontal, sagittal, or transverse planes. The frontal plane involves the varus or valgus of the rearfoot or forefoot. These can be uncompensated, partially compensated, or compensated. The sagittal plane involves equinus, and the transverse plane involves femoral or tibial torsion.
Examples of Foot Deformities in Athletes
Rearfoot varus: a frontal plane deformity where the calcaneus is inverted when the foot is maintained in a subtalar joint neutral position.
Rearfoot valgus: a frontal plane deformity where the calcaneus is everted when the foot is maintained in a subtalar joint neutral position.
Metatarsus adductus: a transverse plane deformity where the forefoot is adducted when compared to the position of the rearfoot. This is also called a c-shaped foot.
Plantarflexed first ray: a sagittal plane deformity where the first metatarsal is plantarflexed in comparison to the other metatarsals when the foot is in its neutral position.
Ankle equinus: a sagittal plane deformity where there is less than 10° of available dorsiflexion at the ankle joint when the subtalar joint is in its neutral position and the midtarsal joint is fully locked.
Forefoot valgus: a frontal plane deformity where the forefoot is everted in reference to the rearfoot when the foot is maintained in a subtalar joint neutral position.
Forefoot varus: a frontal plane deformity where the forefoot is inverted in reference to the rearfoot when the foot is maintained in a subtalar neutral position.
Lower Extremity Pathology
The most commonly reported athletic foot and ankle pathologies are Achilles tendinopathy, plantar fasciitis, and stress fractures [6]. Most common lower extremity pathologies are a result of abnormal foot function. This section reviews which foot types are responsible for causing these pathologic conditions. Evidence-based orthotic treatment recommendations for many of the following conditions are included in Chap. 11.
Calcaneal Apophysitis
Calcaneal apophysitis is a painful condition that affects the growth plate of the calcaneus in young athletes in the 8–15 year age group. Pain is experienced with running and jumping activities in a variety of sports such as basketball, baseball, and soccer. Pain can be reproduced with the squeeze test, applying medial and lateral calcaneal compression to the heel. This condition is related to tight posterior muscle group and plantar fascia. Foot types which can be associated with this condition include forefoot varus (compensated or partially compensated), forefoot supinatus, flexible forefoot valgus, or a compensated equinus or transverse plane deformity. With regard to athletic shoes, a negative heel and poor heel counter can contribute to the problem, as well as poor cushioning of the shoe (Fig. 3.2).
Fig. 3.2
Lateral X-ray view of young athlete with calcaneal apophysitis
Kohler’s Disease
Kohler’s disease is osteochondritis affecting the navicular bone in young children ages 3–9 years old. Symptoms affect the dorsal medial aspect of the navicular area , often causing an antalgic gait with increased lateral column weight bearing to decrease pain.
Freiberg’s Disease
Freiberg’s disease is osteochondrosis of the lesser metatarsal heads. There is a loss of blood supply to the metatarsal heads, generally affecting the second metatarsal head. Most commonly it occurs in the 13–15 age group. Pain and swelling are localized and motion is guarded.
Plantar Fascia Pathology
Often referred to a heel spur syndrome, plantar fasciitis, or plantar fasciosis, this pathology is a common condition with pain at the medial plantar aspect of the calcaneus with pain classically in the morning or following periods of rest. Histologic examination of this process has confirmed a pathology of degeneration rather than inflammation and supports the term fasciosis [7]. Pain can be present during activity. This pain may be associated with inflammation at the origin of the plantar fascia on the calcaneus or as a periosteal reaction to heel spur formation. Both pes cavus and pes planus can lead to this condition. With pes planus the plantar fascia is chronically stretched during foot flattening with excessive calcaneal eversion. Conversely, with a high arch the plantar fascia that is taut and contracted can also lead to this condition. Most causes of heel spur syndrome are mechanical. X-rays can demonstrate the progression of minimal periosteal involvement which can eventually lead to plantar spur formation (Fig. 3.3).
