New fracture pattern focusing on implant fracture for periprosthetic femoral fractures

The History of Classification Systems for Periprosthetic Femoral Fractures: A Literature Review

Periprosthetic femoral fractures (PPFFs) following total hip arthroplasty (THA) present a significant clinical challenge due to their increasing incidence with an aging population and evolving surgical practices. Historically, classifications were primarily based on anatomical fracture location, the stability of the implant, and bone quality surrounding the implant. We critically analyzed 25 classification systems, highlighting the emergence and adaptations of key systems such as the Vancouver classification system (VCS) and the Unified classification system (UCS), which are lauded for their simplicity and effectiveness yet require further refinement. VCS, developed in 1995, categorizes fractures based on the site, implant stability, and bone quality, and remains widely used due to its robust applicability across different clinical settings. Introduced in 2014, UCS expands the VCS to encompass all periprosthetic fractures with additional fracture types, aiming for a universal application. Despite their widespread adoption, these systems exhibit shortcomings, including the incomplete inclusion of all PPFF types and the imprecise assessment of implant stability and surrounding bone loss. These gaps can result in misclassification and suboptimal treatment outcomes. This paper suggests the necessity for ongoing improvements in classification systems to include emerging fracture types and refined diagnostic criteria, ensuring that they remain relevant to contemporary orthopedic practices and continue to facilitate the precise tailoring of treatment to patient-specific circumstances. This comprehensive historical review serves as a foundation for future innovations in classification systems, ultimately aiming to standardize PPFF treatment and improve patient prognosis.

The Effect of Cerclage Banding Distally to a Clamshell Fracture Pattern in Total Hip Arthroplasty-A Biomechanical Study

OBJECTIVES

As currently there is no existing biomechanical work on the topic of interest, the aim of the current study was to investigate the effect of cerclage banding distally to an intraoperatively occurring proximal periprosthetic femoral clamshell fracture versus a non-fractured femur after total hip arthroplasty.

METHODS

A diaphyseal anchoring stem was implanted in twenty paired human cadaveric femora, assigned to a treatment and a control group. In the treatment group, each specimen was fitted with a cerclage band placed 3 mm distally to a clamshell fracture, created with an extent of 40% of the anchoring length of the stem. The resulting fragment was not treated further. The contralateral specimens were left with the stems without further fracture creation or treatment. All constructs were tested under progressively increasing cyclic axial loading until failure. Relative bone-implant movements were monitored by motion tracking.

RESULTS

Number of cycles and the corresponding load at stem loosening, defined as 1 mm displacement of the stem along the shaft axis, were 31,417 ± 8870 and 3641.7 ± 887 N in the control group, and 26,944 ± 11,706 and 3194.4 ± 1170.6 N in the treatment group, respectively, with no significant differences between them, p = 0.106.

CONCLUSION

From a biomechanical perspective, cerclage banding distally to an intraoperative clamshell fracture with an extent of 40% of the anchoring length of the stem demonstrated comparable resistance against hip stem loosening versus a non-fractured femur. It may therefore represent a valid treatment option to restore the full axial stability of a diaphyseal anchoring stem. In addition, it may be considered to keep the medial wall fragment unfixed, thus saving operative time and minimizing associated risks.

The race for the classification of proximal periprosthetic femoral fractures : Vancouver vs Unified Classification System (UCS) - a systematic review

Background

Periprosthetic femoral fractures (PFFs) represent a major cause for surgical revision after hip arthroplasty with detrimental consequences for patients. The Vancouver classification has been traditionally used since its introduction in 1995. The Unified Classification System (UCS) was described in 2014, to widen the spectrum by aiming for a more comprehensive approach. The UCS also aimed to replace the Vancouver classification by expanding the idea of the Vancouver classification to the whole musculoskeletal apparatus. After introduction of the UCS, the question was raised, whether the UCS found its place in the field of analysing PFFs. Therefore, this systematic review was performed to investigate, the use of the UCS compared to the established Vancouver classification.

Methods

Medline was searched for reports published between 1 January 2016 and 31 November 2020, without language restriction. Included were original articles, irrespective of the level of evidence and case reports reporting on a PFF and using either the Vancouver or the UCS to classify the fractures. Excluded were reviews and systematic reviews.

Results

One hundred forty-six studies were included in the analysis. UCS has not been used in a single registry study, giving a pooled cohort size of 3299 patients, compared to 59,178 patients in studies using the Vancouver classification. Since 2016, one study using UCS was published in a top journal, compared to 37 studies using the Vancouver classification (p=0.29). During the study period, the number of yearly publications remained stagnant (p=0.899).

Conclusions

Despite valuable improvement and expansion of the latter UCS, to date, the Vancouver system clearly leads the field of classifying PFFs in the sense of the common use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05240-w.

The reliability and validity of the modified Unified Classification System for periprosthetic femoral fractures after hip arthroplasty

BACKGROUND

This study assessed the reliability and validity of the modified Unified Classification System for femur fractures after hip arthroplasty.

METHODS

Four hundred and two cases were evaluated by 6 observers, 3 experts and 3 trainee surgeons. Each observer read the radiographs on 2 separate occasions and classified each case as to its type. Reliability was assessed by looking at the intraobserver and interobserver agreement using the Kappa statistic. Validity was assessed within the B group by looking at the agreement between the radiographic classification and the intraoperative findings. Interobserver and intraobserver agreement and validity were analyzed, using weighted kappa statistics.

RESULTS

The mean k value for interobserver agreement was found to be 0.882 (0.833-0.929) for consultants (almost perfect agreement) and 0.776 (0.706-0.836) for the trainees (substantial agreement). Intraobserver k values ranged from 0.701 to 0.972, showing substantial to almost perfect agreement. Validity analysis of 299 type B cases revealed 89.854% agreement with a mean k value of 0.849 (0.770-0.946) (almost perfect agreement).

CONCLUSIONS

This study has shown that the modified Unified Classification System is reliable and valid. We believe it is useful to improve the judgment of the implant stability, and establish the therapeutic strategy for periprosthetic femoral fracture.

Breaking Bad: A Comparative Descriptive Analysis of Periprosthetic Fractures Around Cemented and Uncemented Femoral Stems

BACKGROUND

Periprosthetic fractures are most commonly classified according to the Vancouver classification system and more recently the Unified Classification System. The aim of this study is to provide a descriptive analysis of fracture patterns in femoral periprosthetic fractures (PPFs) by femoral stem fixation.

METHODS

A retrospective observational study of all femoral PPFs over a 10-year period at our institution was conducted. Presenting radiographs were examined to assess the fracture pattern.

RESULTS

Over the 10-year period, 138 femoral PPFs that underwent operative treatment were examined. Mean age of patients was 78 years with 45.7% male and median American Society of Anaesthesiologists grade 3. The femoral stem fixation was cemented in 83 patients and uncemented in 55 patients. Uncemented femoral stems most commonly caused a simple oblique fracture pattern (69.1%) with a more comminuted pattern seen in cemented fixation (59%).

CONCLUSION

Fracture patterns differ according to femoral stem fixation. A simple "sickle-like" oblique fracture pattern was more commonly seen in uncemented stems while cemented tapered stems resulted in a comminuted "axe splitting" pattern.

Modification of the Unified Classification System for periprosthetic femoral fractures after hip arthroplasty

BACKGROUND

The Unified Classification System (UCS) for Periprosthetic femoral fractures (PPFF) still has some limitations.

METHODS

We retrieved 18 previous classifications for PPFF based on systematic review of the literature, and also retrospectively analyzed 402 cases with PPFF. 46 cases (11.4%) were identified as beyond the classification scope of the original UCS.

RESULTS

We modified the UCS as follows: (1) add two new B2 subtypes: B2PALT/B2PAGT (i.e., the pseudo ALT/AGT: Fracture in trochanter region including a segment of the proximal medial/lateral femoral cortex); (2) add a new FS category to encompass stem fracture alone or accompanied by PPFF, with FSO designating this fracture with stem fracture alone, FS1 designating this fracture with the proximal portion of the fractured femoral prosthesis being stable, FS2 designating this fracture with the proximal portion of the fractured femoral prosthesis being loose and the surrounding bone quality being good, and FS3 designating this fracture with the proximal portion of the fractured femoral prosthesis being loose and the bone bed being of poor quality; and (3) delete Type F which does not apply to the femur. Thus, using our modification of the UCS, among the 46 cases, we found thirty-five B2PALT, two B2PAGT, three FSO, one FS1, two FS2 and three SF3.

CONCLUSIONS

Compared to the original UCS, our modified version is more comprehensive. We believe it is useful to improve the judgment of the implant stability, and establish the therapeutic strategy for PPFF.

Revision of ASR hip arthroplasty: analysis of two hundred and ninety six recalled patients at seven years

PURPOSE

The aim of this study is to present an algorithm for the evaluation of both symptomatic and asymptomatic patients.

METHODS

From November 2004 to May 2010, there were performed 296 operations: 245 total hip arthroplasty and 51 resurfacing arthroplasty with the ASR DePuy system. In April 2010, there was the first Medical Device Alert regarding all MoM hip replacements in the UK and in August 2010, DePuy recall started worldwide. In March 2012, we started our recall. All patients were invited to undergo clinical investigation, X-ray evaluations, and blood chrome and cobalt level determination. For a short period of time, there were performed second level exams and subsequently, we carried out MARS MRI hip study to all symptomatic patients and there was evidence of ALVAL lesions.

RESULTS

To the patients with ALVAL lesions were proposed surgical hip revision while the others frequent follow-up controls. One hundred patients underwent hip surgical revision.

CONCLUSIONS

We recommend constant MoM THA patients monitoring and early revision if necessary.