Harris & Beath challenged the prevailing view that rigid valgus flat foot is caused by peroneal muscle spasm. Using a clinical case series of 17 patients with electromyography and nerve block experiments, they asked: what actually drives rigid flat foot, and is peroneal spasm cause or consequence? This 1948 paper established tarsal coalition as the primary etiology.
When a patient presents with rigid valgus flat foot and you are tempted to call it 'peroneal spastic flat foot,' stop — this paper is the reason that label was abandoned. In 88% of cases, the cause is structural: a talocalcaneal bridge or calcaneonavicular bar locking the subtalar joint, not muscle spasm.
When you see talonavicular lipping on a lateral foot radiograph, order a 45-degree postero-superior oblique view through flexed knees. Standard AP and lateral views will miss the talocalcaneal bridge entirely.
For treatment: in skeletally immature patients, defer arthrodesis and manage with serial manipulation and orthotic support. When deformity is severe and the skeleton is mature, subtalar and talonavicular arthrodesis via medial approach is the preferred surgical option. Simple resection of the coalition alone gave inferior results in this series.
Harris & Beath challenged the prevailing view that rigid valgus flat foot is caused by peroneal muscle spasm. Using a clinical case series of 17 patients with electromyography and nerve block experiments, they asked: what actually drives rigid flat foot, and is peroneal spasm cause or consequence? This 1948 paper established tarsal coalition as the primary etiology.
When a patient presents with rigid valgus flat foot and you are tempted to call it 'peroneal spastic flat foot,' stop — this paper is the reason that label was abandoned. In 88% of cases, the cause is structural: a talocalcaneal bridge or calcaneonavicular bar locking the subtalar joint, not muscle spasm.
When you see talonavicular lipping on a lateral foot radiograph, order a 45-degree postero-superior oblique view through flexed knees. Standard AP and lateral views will miss the talocalcaneal bridge entirely.
For treatment: in skeletally immature patients, defer arthrodesis and manage with serial manipulation and orthotic support. When deformity is severe and the skeleton is mature, subtalar and talonavicular arthrodesis via medial approach is the preferred surgical option. Simple resection of the coalition alone gave inferior results in this series.