Elsevier

Injury

Volume 50, Issue 3, March 2019, Pages 758-763
Injury

Proposal for the classification of peri-implant femoral fractures: Retrospective cohort study

https://doi.org/10.1016/j.injury.2018.10.042Get rights and content

Highlights

  • This is the first time that data for a systematic classification for peri-implant femoral fractures using a global and common language have been tested.

  • The proposal for classification is simple and easy to memorize and reproduce.

  • Fractures through a correctly implanted nail or plate are not uncommon.

  • The most common peri-implant femoral fractures were located at the diaphyseal segment and associated with nails or plates.

  • The proposed classification for peri-implant femoral fractures appears to be useful and user-friendly.

Abstract

Background Peri-implant fractures occur in association with an implant used to treat a previous injury and that is still attached to the bone. Peri-implant fractures are considered to be relatively “new” fractures and they lack any classification system that is accepted in practice. Generally, the fracture classification systems currently used in our clinical practice were not developed or validated using rigorous scientific evaluation methods.

Aim To provide data for a proposed classification of peri-implant femoral fractures.

Methods This is an international and multicentre study (12 centres) based on a cohort of consecutive peri-implant fractures with the criterion being: a fracture in any segment of the femur in association with previously-used osteosynthesis material, whether a nail, plate or screws. A proposed system for the classification was tested, based on a topographical classification using alphanumeric coding, following a similar nomenclature to that explained in the “Vancouver-Classification-for-Total-Hip-Arthroplasty-Periprosthetic-Fractures”, and classified according to whether the implant is a nail, a screw or a plate, and the location of the fracture in relation to the original implant and the affected femoral segment.

The study coordinator performed the first classification exercise, which was discussed subsequently for the study coordinator group to reach a consensus. A descriptive analysis of the fractures was produced. The proportion of peri-implant femoral fractures was estimated, and 95% confidence interval (95%CI) was calculated.

Results Between January 2013 and December 2016, data on a total of 143 peri-implant femoral fractures were collected.

Only 5 (3.5%) fractures had to be discussed to reach a consensus. The most common peri-implant femoral fractures were located at the diaphyseal segment (#32) and associated with nails or plates: 51%, 73/143, 95%CI:43-59%; at the proximal segment (#31): 39%, 56/143, 95%CI:32-47%; and at the distal femoral segment (#33): 10%, 14/143, 95%CI:6-16%. The highest proportion of peri-implant femoral fractures corresponded to #31-AN (trochanteric and neck area) and #32-CNP (diaphysis fractures distant from the implant, often distal and spiral).

Conclusion The proposed classification for peri-implant femoral fractures appears to be useful and easy to accomplish. Future studies will be necessary to validate it and demonstrate the effectiveness of its application in clinical practice.

Introduction

Peri-implant fracture occurs related to an implant, used to treat an initial injury, and that is still present in the bone. The presence of such implants (nails, plates or screws) causes changes in bone elasticity and creates stress riser areas, which in turn increases the risk of a subsequent femoral fracture [[1], [2], [3]]. The implant may be located in another segment of the bone, but the presence of the original implant material can influence the definitive treatment of the new fracture. We would like to differentiate between peri-prosthetic fractures, which are those that occur in association with the stem of a hip prosthesis or with a total knee prosthesis, and peri-implant femoral fractures which are those that occur in a femur containing implants used for a fracture fixation or an osteotomy. Peri-implant fractures are considered as relatively “new” fractures, and currently lack any classification system that is accepted in practice.

Classification systems have multiple purposes. The term “classification” has several meanings. We consider the most important to be the use of measures to individualize or bring together in a group, i.e. methodically grouping classes, subclasses and categories under logical and definite criteria [[4], [5], [6]]. Generally, the fracture classification systems currently used in clinical practice were not developed or validated by rigorous scientific evaluation methods [7,8]. Classification categories should allow us to make diagnoses with sufficient confidence to limit misclassification and associated treatment errors, and, in addition, should be a useful tool for communication between health professionals [5].

Within the different classifications described for periprosthetic femoral fracture associated with both hip and knee replacement [[9], [10], [11], [12], [13]], there appears to be some consensus on using the Vancouver Classification for fractures around the hip prosthesis [14] and the Rorabeck classification for those related to the knee replacement [15]. The common feature of both is that the diagnostic coding relates the level of the femoral fracture with the location of the implants. In 2013, a global classification was published called the Unified Classification System (UCS), with an extrapolated coding system for all locations in long bones, and valid not just for periprosthetic injuries, but also for peri-implant fractures [16]. Perhaps it is because we are still at the beginning of the peri-implant fractures epidemic, but there is no classification for femoral fractures associated with the material used for internal fixation implanted in the femur, as mentioned above. Therefore, the aim of this study is to provide preliminary data for a proposed peri-implant femoral fractures classification.

Section snippets

Study design

This was a retrospective, international and multicentre study (centres with active AOTrauma members) based on a series of consecutive peri-implant femoral fractures. This study was conducted in accordance with the principles of the Declaration of Helsinki while a high level of confidentiality, in terms of the protection of personal data as required by Spanish Law (LOPD 15/1999), was also ensured.

Study population

All consecutive peri-implant femoral fractures with the criterion of being a fracture in any of the

Results

A total of 143 peri-implant femoral fractures provided by 12 hospitals, all with active AOTrauma members in their respective Trauma Units, were collected during the inclusion period. The demographic characteristics for these patients are shown in Table 2. The previous implant was made of steel in 84 out of 143 (59%) patients and of titanium alloy in the remaining of patients, 59 out of 143 (41%). The intramedullary nails, including the trochanteric nails, were made of titanium in all

Discussion

To our knowledge, this is the first time that data for a systematic classification for peri-implant femoral fractures using a global and common language have been tested. Proper classification of a fracture has to be considered not only based on the fracture lines visible in the X-ray study, but a correct diagnosis must also assess the severity and complexity of the fracture, possible complications, prognosis and the risk inherent to the fracture. The UCS is most likely a good comprehensive

Funding

This work has not received funding

Authorship attributions

MV-C and SV wrote the study protocol and all of the authors approved the final version of it. MV-C, JMS-P, RS-N and ER-P performed the classification of peri-implant femoral fractures. MV-C and SV drafted the manuscript and all of the authors assisted in the successive revisions of the final manuscript. All of the authors participated in the analysis and interpretation of the data, all of the authors read and approved the final version of the manuscript, and they all assume responsibility for

Peri-implant femoral fractures study group

H. Sant Joan Despí – Moises Broggi, Barcelona (Dr Vanesa Vega); H. Clinic of Barcelona, Barcelona (Dr Salvi Prat); H. del Mar, Barcelona (Dr Santos Martinez-Díaz); H. de Barcelona –SCIAS- (Dr Jordi Galí); H. General Universitario de Elche, Alicante (Dr Eladio Saura); H. Jove Gijón, Asturias (Dr Jaime Barrio); H. Trueta de Girona, Girona (Dr Josep-Maria Muñoz); H. Doce de Octubre, Madrid (Dr Carlos Olaya); H. La Vega Baja, Orihuela, Alicante (Dr Javier Rincón); H. Segovia, Segovia (Dr José Maria

Conflicts of interest

All of the authors declare that they have no conflict of interest.

Dr. Miquel Videla-Cés is a PhD candidate in the Universitat de Barcelona, Spain.

Acknowledgments

Special thanks to Dr. Joan Girós for his support with this manuscript.

References (27)

  • M.E. Müller et al.

    CCF Comprehensive Classification Of Fractures. Pamphlets I and II

    (1996)
  • M.E. Müller et al.

    Comprehensive classification system for long bone fractures. Editions scientifiques et médicales

    (2000)
  • R. Orozco et al.

    Atlas of internal fixation. Fractures of long bones

    (1999)
  • Cited by (0)

    View full text