Cozen’s phenomenon: a reminder^a

Abstract

A four-year-old child attended Accident and Emergency following a fall from a slide with a displaced and angulated proximal tibial metaphyseal fracture. Treatment included closed manipulation under anaesthesia and an above knee cast for seven weeks. Serial radiographs over the following few months were satisfactory demonstrating good alignment and evidence of healing. However, at four-months review new-onset genu valgum with mechanical axis deviation was noted. No evidence of spontaneous resolution was noted over the following 12 months and hence a corrective hemi-epiphysiodesis was performed. At 12-months post-operatively, there was marked clinical and radiographical improvement in alignment. Classically Cozen's phenomenon is described as the late-onset post-traumatic valgus deformity associated with proximal tibial metaphyseal fractures in children. We want to reemphasise the early recognition of children at risk of this unique complication. In addition, we wish to highlight the progression of the late-onset valgus and its subsequent management.

Cozen's Phenomenon After Repair of a Medial Collateral Ligament Periosteal Avulsion in a Pediatric Athlete

“…The proximal tibial genu valgum phenomenon, known as Cozen's phenomenon, was first described by Lewis Cozen in 1953 as a potential complication after fractures of the proximal tibial metaphysis 3 . Since that time, Cozen's phenomenon has also been found to be associated with the harvesting of proximal tibial bone graft, proximal tibial osteotomies, biopsy, traction pin insertion, and osteomyelitis of the proximal tibial metaphysis 4 ; however, proximal tibial metaphyseal fracture remains the most common etiology of Cozen's phenomenon.…”

Initial angular deformity and its recovery of the proximal tibial metaphyseal fracture according to the cause: Trampoline-related injury versus other injuries

“…In the past, proximal tibial metaphyseal fractures were reported to have clinical importance because of the possibility of tibial valgus deformity after trauma, 7,14 and angular deformity might progress after bone union. 15 Although the precise pathogenesis of valgus deformity is not fully understood, there have been several proposed hypotheses, including iliotibial band or fibular tethering effect, 7 unbalanced blood supply between the medial and lateral cortices, 8,[16][17][18] and entrapment of periosteum to the fracture gap. 19 Incomplete fracture that involves either medial or lateral cortex may cause not only initial varus/valgus deformity but also aggravation of deformity caused by the overgrowth of involved cortex due to increased blood supply.…”

Late Onset Deformity in a Healed Fracture: A Case of Paediatric Post Traumatic Tibia Valga

“…With the intact fibula acting as a tether, valgus angulation develops. The late deformity in the wake of successful fracture healing is a cause of distress for caretakers and has been reported to lead to mitigation of the treating surgeon [4,6].…”