Assessing leg length after fixation of comminuted femur fractures

Abstract

Background: Nailing comminuted femur fractures may result in leg shortening, producing significant complications including pelvic tilt, narrowing of the hip joint space, mechanical and functional changes in gait, an increase in energy expenditures, and strains on spinal ligaments, leading to spinal deformities. The frequency of this complication in patients managed with an intramedullary (IM) nail for comminuted diaphyseal fractures is unknown.

Questions/purposes: We therefore determined (1) the frequency of LLDs, (2) whether a specific fracture pattern was associated with LLDs, (3) the frequency of reoperation, and (4) whether revision fixation ultimately corrected the LLD.

Methods: We studied 83 patients with 91 AO/OTA Type B or Type C fractures fixed with either an antegrade or retrograde IM nail from July 2002 through December 2005. There were 60 males and 23 females, with a mean age of 30 years (range, 15-79 years). All underwent a digitized CT scan in the immediate postoperative period. Measurements of both legs were performed. Any fixation producing a discrepancy and requiring a return to surgery was identified.

Results: An mean LLD of 0.58 cm was found in 98% of the patients, but only six (7%) patients had an LLD of greater than 1.25 cm. No fracture pattern or the presentation of bilateral injuries demonstrated a greater incidence of LLD. Of the patients with LLD, two patients refused further surgery while the remaining four patients, two Type B and two Type C fractures, ultimately underwent revision fixation. Repeat CT scans after revision surgery of all four patients demonstrated a residual LLD of only 0.2 cm.

Conclusions: Postoperative CT scans appear to be an efficient method to measure femoral length after IM nailing. Although residual LLDs may be common in comminuted femurs treated with IM nails, most LLDs do not appear to be functionally relevant. When an LLD of greater than 1.5 cm is identified, it should be discussed with the patient, who should be told that potential complications may occur with larger LLDs and that sometimes patients may benefit from repeat surgery.

Level of evidence: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Fig. 1A–B

(A) A clinical photograph shows the length of the Bell-Thompson ruler. (B) A fluoroscopic image demonstrates the measurements of the Bell-Thompson ruler as it is projected onto the knee.

Fig. 2A–C

(A) A CT scan demonstrates a distraction of 1.5 cm after antergrade nailing of a Type C fracture performed on a fracture table. (B) An intraoperative fluoroscopic image shows the distracted femur fracture. (C) Using a back-slapping technique, a fluoroscopy image demonstrates that the distraction has been corrected.