Far Cortical Locking of Distal Femur Fractures: A Prospective Observational Study

2012-02-15 文章来源：2012AAOS 点击量：2115 　　我要说

Session:	TRA Posters-Trauma Posters
Date/Time:	Tuesday, Feb 07, 2012, 8:00 AM - 6:00 PM Poster Hall/ Multimedia/ Scientific Exhibits: Tuesday, Feb 7 - Saturday, Feb 11, 2012, 8:00 AM - 6:00 PM
Presentation Number:	P515
Posterboard Number:	P515
Title:	Far Cortical Locking of Distal Femur Fractures: A Prospective Observational Study
Classification:	Trauma
Keywords:	Femur/Patella; Fracture Healing; Internal/External Fixation
Author(s):	Michael Bottlang, PhD, Portland, Oregon, United States Daniel J. Phelan, BS, Portland, Oregon, United States Daniel C. Fitzpatrick, MD, Eugene, Oregon, United States Corey J. Vande Zandschulp, MD, Portland, Oregon, United States Daniel V. Sheerin, MD, Eugene, Oregon, United States Steven M. Madey, MD, Portland, Oregon, United States
Abstract:	INTRODUCTIONRecent studies show a nonunion rate of 19-22% for supracondylar femur fractures treated with conventional locked plates. The relatively high stiffness of these constructs is thought to play a role in the nonunion rate. FCL constructs have been shown to decrease construct stiffness by 80% and to yield 156% stronger healing in an ovine tibia fracture model. This prospective study documents for the first time the clinical performance of FCL constructs. METHODSIn a prospective observational study, distal femur fractures (AO/OTA 33A and 33C) in 14 consecutive patients were stabilized in a percutaneous bridge plating approach using a titanium periarticular locking plate with four FCL screws in the diaphysis. Standard locking screws were used for metaphyseal fixation. No bone grafts or bone morphogenic proteins were administered to enhance fracture healing. Healing was assessed by the number of bridged cortices on radiographs at week 6 (n=14), week 12 (n=10), and week 24 (n=5) and by CT at 12 weeks post surgery. Periosteal callus size was objectively measured at the medial, anterior and posterior cortices using a validated computational algorithm with an error of less than 5%. Callus measurements were compared to a published series of historic control data from 66 distal femur fractures treated with standard locked plating constructs. RESULTSAverage patient age was 74 years (range 55-89). Of the 14 patients, one was a smoker and four had diabetes. There was one open fracture and eight periprosthetic fractures. At week 12, bridging callus was present in 71% of medial, posterior, and anterior cortices. At week 24, bridging callus was present in 96% of medial, posterior and anterior cortices (Figure 1), whereby at least two of the three cortices were bridged in all patients. The average periosteal callus size was 113 mm2 (week 6), 154 mm2 (week 12), and 157 mm2 (week 24) compared to historic control data of 62 mm2 (week 6, p=0.01), 93 mm2 (week 12, p=0.09) and 114 mm2 (week 24, p=0.4) for standard locked plating constructs. In addition to increased callus size, FCL fixation yielded considerably symmetric callus distribution (week 6: 31% medial, 27% anterior, 42% posterior callus). There was no incidence of hardware failure. There was no failure of FCL fixation in the diaphysis. One periprosthetic fracture migrated into varus due to deficient metaphyseal fixation but did not require revision. DISCUSSION AND CONCLUSIONResults suggest that FCL constructs can improve callus formation relative to historic controls of fractures treated with standard locked plate constructs in early follow up. There were no instances of hardware complications or fixation failure related to FCL screws.

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