The collapse of the medial longitudinal arch, increased hindfoot valgus (eversion), and forefoot abduction in the foot of this 12-year-old girl (when weight bearing) are all typical features of a flexible flatfoot deformity.
The collapse of the medial longitudinal arch, increased hindfoot valgus (eversion), and forefoot abduction in the foot of this 12-year-old girl (when weight bearing) are all typical features of a flexible flatfoot deformity. The foot may also appear externally rotated in relation to the leg.
Pes planus, or flatfoot, has a variety of causescongenital, developmental, neuromuscular, inflammatory, and infectious. Fortunately, the vast majority of children with flatfoot have hypermobile or flexible flatfoot; this is a manifestation of generalized ligamentous laxity, which is an autosomal dominant trait. Flexible flatfoot is usual in infants, common in children, and within normal limits in adults.1,2
Physical examination. In flexible flatfoot, the ankle, subtalar, and transverse tarsal joints usually demonstrate full range of motion. The medial longitudinal arch returns in the nonweight-bearing position or when the child stands on his or her toes. There may be some callus formation over the medial aspect of the talonavicular joint from collapse of the medial longitudinal arch and increased pressure with shoe wear. Fortunately, this is rarely symptomatic. In painful or rigid flatfoot, there is usually decreased subtalar and midfoot motion. In the nonweight-bearing position, and when standing on the toes, the medial longitudinal arch will not reform.3
Radiographic evaluation. In children with rigid flatfoot, it is important to perform a more extensive evaluation to determine the exact cause.
AP and lateral weight-bearing radiographs of the feet are required for radiographic evaluation of symptomatic flatfoot.1,2 In the lateral view, there is an increased lateral talocalcaneal angle, a talonavicular sag, and parallel alignment of the metatarsals. Additional views may also be necessary, depending on the suspected diagnosis. In tarsal coalition, an oblique view of the foot will reveal a calcaneonavicular coalition. If a middle facet talocalcaneal coalition is suspected, CT will be diagnostic.
Management. In the vast majority of children, flatfoot can be managed by observation. The indication for treatment with an orthosis is typically pain or abnormal shoe wear. Severely flat or pronated feet may cause abnormal medial shoe wear. When this happens, the use of an orthosis that restores the medial longitudinal arch may be beneficial in relieving symptoms and improving shoe longevity. This can be accomplished with athletic shoes with built-in arch supports, commercially available inserts or, in some cases, a custom-made orthosis. The last is only occasionally indicated because of its expense. Moreover, an orthosis will not permanently correct a pes planus deformity.4,5 The foot will still have a flat or pronated appearance.
Operative treatment of hypermobile flatfoot is rarely indicated. However, in certain children, lengthening of the neck of the calcaneus and plication of the talonavicular joint capsule may be beneficial.3 Midfoot fusions have also been reported to produce satisfactory long-term results.6 However, these fusions restrict motion and produce added stress on the remaining mobile joints. Subtalar joint arthroplasties are contraindicated.7
In children with tarsal coalitions, such as a calcaneonavicular or middle facet talocalcaneal coalition, resection and soft tissue interposition may help restore motion and relieve symptoms.
REFERENCES:1. Sullivan JA. Pediatric flatfoot: evaluation and management. J Am Acad Orthop Surg. 1999;7:44-53.
2. Staheli LT, Chew DE, Corbett M. The longitudinal arch: a survey of eight hundred and eighty-two feet in normal children and adults. J Bone Joint Surg. 1987;69A:426-428.
3. Mosca VS. Instructional course lectures: flexible flatfoot and skewfoot. J Bone Joint Surg. 1999;81B:858-862.
4. Staheli LT. Footwear for children. Instr Course Lect. 1994;43:193-197.
5. Wenger DR, Maudlin D, Speck G, et al. Corrective shoes and inserts as treatment for flexible flatfoot in infants and children. J Bone Joint Surg. 1989;71A:800-810.
6. Fraser RK, Menelaus MB, Williams PF, Cole WG. The Miller procedure for mobile flat feet. J Bone Joint Surg. 1995;77B:396-399.
7. Black PR, Betts RP, Duckworth T, Smith TW. The Viladot implant in flatfooted children. Foot Ankle Int. 2000;21:478-481.