Seymour Fracture - Hand

Introduction
Displaced distal phalangeal physeal fracture with an associated nailbed injury Epidemiology incidence 20% to 30% of phalangeal fractures involve the physis in children body location middle finger injury is most common type of the distal phalangeal physeal fracture: metaphyseal fractures 1 to 2 mm distal to the epiphyseal plate Salter-Harris I fractures Salter-Harris II fractures type of nailbed injury: nailbed laceration nail plate subluxation interposition of soft tissue at fracture site (usually germinal matrix) Pathophysiology mechanism of injury direct trauma or crush injury (e.g. caught in door, heavy object or sport) pathoanatomy similar mechanism to mallet finger in adults injury causes flexed posturing of the distal phalanx deformity results from an imbalance between the flexor and the extensor tendons at the level of the fracture imbalance occurs due to different insertion sites of flexor and extensor tendons extensor tendon inserts into the epiphysis of the distal phalanx flexor tendon inserts into metaphysis of the distal phalanx widened physis likely to have interposed tissue in the fracture site Prognosis operative intervention is warranted to ensure that there is no interposed tissue in the fracture site failure to recognize injury may result in: nailplate deformity physeal arrest chronic osteomyelitis
Presentation
Physical exam apparent mallet deformity echymosis and swelling nail plate lying superficial to the eponychial fold
Imaging
Radiographs recommended views PA may appear normal lateral findings widened physis or displacement between epiphysis/metaphysis flexion deformity at fracture site seen on lateral view
Differential Diagnosis
Mallet finger pediatric mallet finger is usually osseous avulsion (SH III and SH IV) mallet finger fracture line enters DIPJ, while Seymour fracture line traverses physis (does not enter DIPJ)
Treatment
Nonoperative closed reduction and splinting indications minimally displaced, closed fracture no interposition of soft tissue at fracture site Operative closed reduction and pinning across DIPJ indications displaced, closed fracture no interposition of soft tissue at fracture site antibiotics, open reduction and pinning across DIPJ, nailbed repair open management has fewer complications than closed management indications open fracture technique hyperflexion of the digit will permit removal of the interposed soft tissue from the fracture site thorough irrigation and debridement anatomical reduction and retrograde k-wire fixation crossing the fracture site and DIP joint nailbed injury repair
Complications
Nail dystrophy Growth disturbance of the distal phalanx and nail Secondary fracture displacement Chronic osteomyelitis (failure to treat as open fracture) Flexion deformity