Proposal for the classification of peri-implant femoral fractures: Retrospective cohort study
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)
- et al.
Occurrence of secondary fracture around intramedullary nails used for trochanteric hip fractures: a systematic review of 13,568 patients
Injury
(2012) - et al.
Risk factors for periprosthetic femoral fracture
Injury
(2007) - et al.
Interprosthetic femoral fractures: analysis of 14 cases. Proposal for an additional grade in the Vancouver and SoFCOT classifications
Orthop Traumatol Surg Res
(2011) - et al.
Classification of femoral periprosthetic fractures
Injury
(2007) - et al.
Interprosthetic femoral fractures–a challenge of treatment. A systematic review of the literature
Injury
(2014) - et al.
Classification of periprosthetic fractures complicating total knee arthroplasty
Orthop Clin North Am
(1999) - et al.
Peri-implant femoral fractures: the risk is more than three times higher within PFN compared with DHS
Injury
(2016) - et al.
Interobserver variation using the AO/ASIF classification of long bone fractures
Injury
(1993) - et al.
A retrospective cohort study of concomitant ipsilateral extra-capsular and intra-capsular fractures of the proximal femur. Are they casual findings or an undervalued reality?
Injury.
(2017) - et al.
More postoperative femoral fractures with the Gamma nail than the sliding screw plate in the treatment of trochanteric fractures
Acta Orthop Scand
(2001)