Triplane Fracture

The triplane fracture is also known as the Marmor-Lynn fracture and typically occurs in adolescents. The term actually refers to three fractures of the tibia: a vertical fracture through the epiphysis, a horizontal fracture through the physis, and an oblique fracture through the metaphysis. Twisting injuries produce this type of fracture.
A AP radiograph of the ankle. The horizontal fracture through the lateral tibial physis is apparent as well as the vertical fracture through the epiphysis.

B Lateral radiograph of the ankle. The metaphyseal fracture line is visible within the tibia.

Links to online textbooks

Wheeless' Orthopedics: discussion of triplane fractures

References:

Karrholm J: The triplane fracture: four years of follow-up of 21 cases and review of the literature J Pediatr Orthop B. 1997 Apr;6(2):91-102. [See related articles]
van Laarhoven CJ, Severijnen RS, van der Werken C: Triplane fractures of the distal tibia J Foot Ankle Surg. 1995 Nov-Dec;34(6):556-9. [See related articles]

A	AP radiograph of the ankle. The horizontal fracture through the lateral tibial physis is apparent as well as the vertical fracture through the epiphysis.
B	Lateral radiograph of the ankle. The metaphyseal fracture line is visible within the tibia.