Dynamic Locked Plating of Distal Femur Fractures.

OBJECTIVES

Nonunion after locked bridge plating of comminuted distal femur fractures is not uncommon. "Dynamic" locked plating may create an improved mechanical environment, thereby achieving higher union rates than standard locked plating constructs.

SETTING

Academic Level 1 Trauma Center.

PATIENTS/

PARTICIPANTS

Twenty-eight patients with comminuted supracondylar femur fractures treated with either dynamic or standard locked plating.

INTERVENTION: Dynamic plating was achieved using an overdrilling technique of the near cortex to allow for a 0.5-mm "halo" around the screw shaft at the near cortex. Standard locked plating was done based on manufacturer's suggested technique. The patients treated with dynamic plating were matched 1:1 with those treated with standard locked plating based on OTA classification and working length.

MAIN OUTCOME MEASUREMENTS: Three blinded observers made callus measurements on 6-week radiographs using a 4-point ordinal scale. The results were analyzed using a 2-tailed t test and 2-way intraclass correlations.

RESULTS

The dynamic plating group had significantly greater callus (2.0; SD, 0.7) compared with the control group (1.3: SD, 0.8, P = 0.048) with substantial agreement amongst observers in both consistency (0.724) and absolute score (0.734). With dynamic plating group, 1 patient failed to unite, versus three in the control group (P = 0.59). The dynamic group had a mean change in coronal plane alignment of 0.5 degrees (SD, 2.6) compared with 0.6 (SD, 3.0) for the control group (P = 0.9) without fixation failure in either group.

CONCLUSIONS

Overdrilling the near cortex in metaphyseal bridge plating can be adapted to standard implants to create a dynamic construct and increase axial motion. This technique seems to be safe and leads to increased callus formation, which may decrease nonunion rates seen with standard locked plating.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.