Implant cut-out following cephalomedullary nailing of intertrochanteric femur fractures: Are helical blades to blame?. Issue 4 (April 2019)

• Record Type: Journal Article
• Authors: Ibrahim, Ishaq; Appleton, Paul T.; Wixted, John J.; DeAngelis, Joseph P.; Rodriguez, Edward K.
• Is Part Of: Injury. Volume 50:Issue 4(2019)
• Page Start: 926
• Page End: 930
• Publication Date: 2019-04
• Subjects: Hip fractures -- Cephalomeduallary nail -- Cut-out -- Helical blade -- Tip-apex distance -- Medial perforation; Wounds and injuries -- Surgery -- Periodicals; Accidents -- Periodicals; Wounds and Injuries -- surgery -- Periodicals; Lésions et blessures -- Chirurgie -- Périodiques; Electronic journals; Electronic journals; 617.1
• DOI: 10.1016/j.injury.2019.02.015
• Languages: English
• ISSNs: 0020-1383

Abstract

Highlights: Cephalomeduallary (CMN) nail cut-out continues to occur at an unacceptably high rate, affecting 6.4% of the current study population. Contrary to earlier studies involving CMN cut-out after treatment of geriatric hip fractures, no difference in rate of cut-out was observed between helical blade and lag screws in the current study. Amongst risk factors for cut-out examined in the current study, fracture reduction quality was the sole variable associated with increased risk for implant cut-out. When considering mechanisms of failure, medial perforation occurs at a significantly higher rate with helical blades than lag screws. A lower Tip-Apex Distance may increase risk for cut-out following helical blade fixation. Abstract: Introduction: Implant cut-out remains a common cause of cephalomedullary nail (CMN) failure and patient morbidity following surgical treatment of intertrochanteric femur fractures. Recent studies have suggested an increased rate of CMN cut-out with helical blades as opposed to lag screws. We compared rates of overall cut-out between helical blades and lag screws and used bivariate and multivariate analysis to determine the role of proximal fixation method among other variables on risk for cut-out. Subgroup analysis was performed on the basis of failure mechanism; superior migration (Fig. 2 ) versus medial perforation (Fig. 3 ). Methods: Three-hundred and thirteen patient charts were retrospectively reviewed over an 8-year period; 245 patients were treated with helical blades and 68 with lag screws. Radiographs were reviewed for fracture pattern, Tip-Apex Distance (TAD), Parker's Ratio (PR) and reduction quality. Rate of implant cut-out was compared between groups and multiple logistic regression was used to analyze the ability of several independent variables to predict implant cut-out. Results: Twenty cut-outs occurred; 15 with helical blades and 5 with lag screws. No difference in the rate of cut-out was observed between the two groups (p = 0.45). Poor fracture reduction was found to be a significant predictor of implant failure via bivariate and multiple logistic regression analysis (p = <0.01, OR 23.573). Helical blade fixation, fracture instability, TAD ≥ 25, and PR ≥ 0.45 were not predictive of implant cut-out during multivariate analysis. Similarly, patient smoking status and surgeon trauma fellowship training did not significantly increase the odds of implant cut-out. Failure by medial perforation occurred in 12 instances, all involving helical blades. Failure by superior migration occurred at a significantly higher rate with lag screws than helical blades (p = 0.02). Conclusion: CMN cutout is likely multifactorial. A direct association between helical blade fixation and implant cut-out was not observed in our study. Amongst modifiable risk factors for implant failure, poorer fracture reduction was predictive of failure by cut-out. Subgroup analysis highlights differing modes of failure between lag screws and helical blades which warrants further investigation. Ideal TAD during helical blade fixation remains unknown.