Bimalleolar ankle fracture in an adolescent with tillaux fracture.

The purpose of this case report is to present an unusual fracture pattern in an 11-year-old patient characterized by both a predominantly adult fracture type and an exclusively adolescent fracture type. The patient sustained a bimalleolar ankle fracture while sledding. A difficult to detect Tillaux fracture was discovered on preoperative radiograph. The fractures were operatively treated by open reduction and internal fixation. The fracture mechanism is most likely attributed to supination-external rotation injury. The patient thus far has no sign of permanent deformity or disability. This case is unique in that it illustrates an adult fracture type in an adolescent patient. The nearly hidden Tillaux fracture also emphasizes the importance of thorough radiographic examination of any fracture.

Epiphysiodesis with infusion of stromal cell-derived factor-1 in rabbit growth plates.

BACKGROUND: The mechanism of physeal closure is poorly understood, although both mechanical and biological factors may play a role in the process. In this study, we evaluated the effect of the application of a chemokine stromal cell-derived factor-1 (SDF-1) to rabbit physes in vivo with regard to growth inhibition. METHODS: A continuous infusion system consisting of a fenestrated catheter and an osmotic pump were implanted into the right proximal tibial physis of twenty six-week-old New Zealand White rabbits. Ten of the pumps were loaded with human recombinant SDF-1alpha, and ten were loaded with phosphate-buffered saline solution (sham treatment). The left leg was used as the uninvolved control. The growth of the tibiae was followed radiographically for eight weeks, and histologic analysis was performed for both the SDF-1-treated rabbits and the sham-treated rabbits at two, four, and eight-week time-points. RESULTS: Radiographic evaluation showed a significant growth inhibition in the SDF-1alpha-treated physes (4.5 +/- 3.0 mm; p = 0.007) compared with the sham-treated physes after eight weeks. No difference was noted when the sham-treated leg was compared with the contralateral, control leg (0.2 +/- 2.9 mm; p = 0.465). Histologic evaluation showed marked physeal disorganization, narrowing, and proteoglycan loss and a significant decrease in physeal height (p < 0.0001) for the SDF-1-treated group. Reversible growth slowing was noted in the uninvolved, control leg of the SDF-1-treated group at six weeks, with resolution of the difference by eight weeks. CONCLUSIONS: SDF-1 may be used to induce physeal closure through a targeted infusion system. However, transient systemic effects of SDF-1 may exist and must be evaluated further prior to its clinical use for epiphysiodesis.