Intramedullary Nail Breakage and Mechanical Displacement in Patients with Proximal Femoral Fractures: A Commercial and Medicare Supplemental Claims Database Analysis

Abstract

Objective This study evaluated the rates and patterns of intramedullary nail (IMN) breakage and mechanical displacement for proximal femur fractures and the factors associated with their occurrence. Patients and Methods Patients with subtrochanteric, intertrochanteric, or basicervical femoral neck fractures treated with IMN from 2016 to 2019 were identified from commercial and Medicare supplemental claims databases and were followed for up to two years. Kaplan–Meier analysis estimated the cumulative incidence of and patterns of breakage/mechanical displacement. Multivariable Cox regression models evaluated the factors associated with breakage/mechanical displacement. Results A total of 11,128 patients had IMN fixation for subtrochanteric, intertrochanteric, or basicervical femoral neck fractures: (mean SD) age 75.6 (16.4) years, 66.2% female, 74.3% Medicare supplemental vs 26.7% commercial insurance. Comorbidities included hypertension (62.9%), osteoporosis (27.3%), cardiac arrhythmia (23.1%), diabetes (30.7%), and chronic pulmonary disease (16.3%). Most fractures were closed (97.2%), intertrochanteric or basicervical femoral neck (80.1%), and not pathological (91.0%). The cumulative incidence of nail breakage over two years was 0.66% overall, 1.44% for combination fractures, 1.16% for subtrochanteric fractures, and 0.49% for intertrochanteric or basicervical fractures. The cumulative incidence of mechanical displacement was 0.37% overall, 0.43% for subtrochanteric fractures, 0.42% for combination fractures, and 0.36% for intertrochanteric or basicervical femoral neck fractures. Half of the breakages occurred within five months after surgery and half of the mechanical displacements occurred within 75 days. Age 50–64 (vs 75+) and subtrochanteric or pathological fracture were more commonly associated with nail breakage. Complicated hypertension was more commonly associated with mechanical displacement. Conclusion The incidence of IMN breakage and mechanical displacement in US commercial and Medicare supplemental patients with proximal femur fractures from 2016 to 2019 was low (0.66% and 0.37%, respectively up to two years). Age 50–64 (vs 75+) and subtrochanteric or pathological fracture were more commonly associated with breakage. Complicated hypertension was associated with mechanical displacement.

Defining Cephalomedullary Nail Breakage Rates: A Systematic Review and Meta-Analysis

“…Only 2 studies accounted for censoring of patients due to death. 13,15 In contrast, the rate could potentially be lower than reported, such as if breakages were diagnosed when they did not occur (coding or documentation errors) or partial capture of patients at risk (missing patients that had the implants inserted).…”

“…The Medicare supplemental claims database as an example excludes patients younger than 65 years of age, and because young age is a risk factor for implant breakage, this dataset may underestimate breakage rates. Chitnis et al 15 derives 74% of its study population from the Medicare supplemental claims database. It is also worth noting that 3 of the 4 large-scale database searches were conducted by employees of a medical technology company that manufactured the implant it studied, which would have the potential to introduce bias from conflict of interest.…”

“…It is also worth noting that 3 of the 4 large-scale database searches were conducted by employees of a medical technology company that manufactured the implant it studied, which would have the potential to introduce bias from conflict of interest. [14][15][16] With no gold standard reference, the true accuracy of all of the studies remains unknown.…”

“…For database papers, 3 of the studies detected breakage by ICD code searches for "breakdown of internal device" AND (femur fracture repair OR device removal from femur) occurring in one hospital admission. [14][15][16] The fourth study detected revisions defined as any operation after index procedure in which a component was removed and/or replaced; however, it did not specify how the database was queried for that outcome. 13 Those patients then had a hospital record review.…”

“…12 To increase participant numbers, some authors have interrogated large-scale US health care databases. [13][14][15][16] These are considered administrative rather than clinical databases, because the information is typically compiled from billing information and is not recorded primarily for clinical research purposes. 17 Administrative databases that use the International Classification of Diseases (ICD) codes to capture implantation or breakages rely on accurate translation of records and operation reports by health information managers who may not understand the differences between implant types or revision procedures.…”