Fracture of VerSys fully bead-coated long femoral stems: Report on four fractures in 41 hips

A New Type of Periprosthetic Fracture: Is It the Time to Update the Unified Classification System?

INTRODUCTION

Increased number of primary and revision arthroplasties performed globally has led to a surge in the numbers of periprosthetic fractures. The Unified Classification System (UCS) advocated a rational approach towards the classification of periprosthetic fractures. We present here an update to the UCS with addition of new fracture pattern encountered in orthopedic practice.

METHODS

A retrospective study was conducted to review the service arthroplasty register for the cases with unique fracture pattern where the periprosthetic fracture around total hip arthroplasty was also associated with fracture of the prosthetic component. The details were retrieved from the medical record and the patients were called for a review. The radiological assessment was done with X-rays and clinical assessment with Harris Hip Scores at the latest follow-up.

RESULTS

Between 2012 and 2019, 11 patients (7 males and 4 females) were operated for peri-prosthetic fracture with a unique pattern where the fracture of femur was associated with fracture of the femoral stem as well. The mean age of the patient at the time of fracture was 56.8 years (range 42-71 years). All patients were managed with revision hip surgery. One patient died due to malignancy after 7 years of revision surgery. All the surviving patients are doing well with a mean Harris Hip Score of 86.8 at the latest follow-up of 2-9 years (mean 5.0 years).

CONCLUSION

With emergence of this new fracture pattern, it is recognition as a separate entity would help in better understanding and augmentation of the existing classification system of periprosthetic fractures.

Nonoperative Treatment of a Fractured Uncemented Extensively Coated Femoral Stem: A Case Report with 2-Year Follow-up

CASE

A 62-year-old man who underwent total hip arthroplasty (THA) 17 years earlier presented with a fractured uncemented extensively coated diaphyseal engaging femoral stem. Treatment options, including revision surgery, were discussed, and the patient elected for nonoperative treatment. At 2 years of follow-up, the patient is asymptomatic, radiographs are stable, and he lives an active lifestyle without restrictions.

CONCLUSION

Fractures of well-fixed femoral prostheses are rare complications of THA and almost universally require revision surgery. Nonoperative treatment without activity restrictions may be a viable treatment option in select patients to preserve function and maintain quality of life.

Bilateral Fractures of Anatomic Medullary Locking Hip Arthroplasty Stems in a Single Patient: A Case Report

Introduction:

Stem fracture is a rare complication of total hip arthroplasty (THA) using fully porous-coated femoral stems. Bilateral fractures in a single patient have not been previously reported.

Case Report:

A 48-year-old female underwent bilateral staged primary THA with fully porous-coated anatomic medullary locking femoral prostheses. She subsequently sustained stem fractures of her right and left prostheses in the 13thand 14thyears after their implantation, respectively.

Conclusion:

The bilateral nature of this rare complication in a single patient supports the notion that stem fracture results from a mismatch between the mechanical stresses encountered in vivo and the structural properties of small-diameter stems. Surgeons should be cognizant of this potential complication when evaluating patients at long-term follow-up with new-onset pain.

Risk factors for femoral stem breakage: an analysis of the AOANJRR results

INTRODUCTION

Breakage of the femoral stem component of a total hip replacement is now uncommon but continues to be seen with certain stem designs and in certain patient groups. Data previously published on this topic has been limited, either gathered from a single surgeon or centre, or included only a single stem design.

METHODS

We reviewed the data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), identified and analysed 143 stem breakages over a period of 16 years, covering 44 different stem designs.

RESULTS

Our data confirms previously published findings that risk factors for stem breakage include patient age at implantation of under 70, male gender, as well as the use of exchangeable necks. We found no association with initial diagnosis, or type of acetabular component implanted. We did however also find, excluding exchangeable neck designs, that after 4.5 years a cemented stem had a significantly higher risk of breakage then a cementless stem.

DISCUSSION

To our knowledge this is the 1st paper to suggest cemented fixation as a specific risk factor for stem breakage. The analysis of rare complications such as stem breakage is only possible through large data collection systems such as the AOANJRR. Whilst there have been recent advances in materials and manufacturing techniques, we recommend that surgeons are aware of all the specific risks when considering implant choices for individual patients.

What Is the Risk of Revision Surgery in Hydroxyapatite-coated Femoral Hip Stems? Findings From a Large National Registry

BACKGROUND

Despite wide adoption of hydroxyapatite (HA)-coated femoral stems in THA, no studies have found differences in the risk of revision surgery with its use or investigated the interaction of different prosthesis designs with stem coating.

QUESTIONS/PURPOSES

The purpose of this study was to evaluate the risk of revision in THAs with HA-coated stems compared with non-HA-coated. To achieve this purpose, we asked: (1) What is the difference in risk of revision of THAs with HA-coated femoral stems compared with non-HA-coated using an aggregate analysis? (2) What is the difference in risk of revision of THAs with HA-coated femoral stems compared with non-HA-coated for five prosthesis types that used the same femoral and acetabular component combination but where the femoral stem had both a HA and non-HA coating option?

METHODS

The Australian Orthopaedic Association National Joint Replacement Registry analyzed cementless primary THA registered between September 1, 1999, and December 31, 2014. Of the 147,645 cases that fit our selection criteria, 81.1% (N = 119,673) had HA-coated stems. Overall (that is, all procedures with any prostheses in the registry) and five prosthesis designs where both an HA-coated stem and non-HA-coated stem exist (Zimmer's VerSys®/Trilogy® [N = 3924], Biomet's Mallory-Head®/Mallory-Head [N = 2538], Smith & Nephew's SL-Plus/EP Fit-Plus [N = 2028], Biomet's Taperloc®/Exceed [N = 1668], and Biomet's Taperloc/Mallory-Head [N = 1240]) were evaluated. Revision surgery was the outcome of interest. Survival analyses were conducted and hazard ratios (HRs) were adjusted for age, sex, bearing surface, femoral head size, and acetabular component HA coating.

RESULTS

In the overall cohort, HA stems had a lower any-cause revision risk after 6 months (HR, 0.83; 95% confidence interval [CI], 0.72-0.95; p = 0.007). However, the risk of revision varied when we evaluated the effect of HA on revision for specific prothesis combinations that had both HA and non-HA options for the femoral stem. VerSys/Trilogy, Mallory-Head/Mallory-Head, Taperloc/Exceed, and Taperloc/Mallory-Head did not have a lower risk of any-cause revision with HA-coated stems compared with non-HA-coated. Only the SL-Plus/EP Fit-Plus subgroup showed a lower risk of revision for loosening (HR, 0.17; 95% CI, 0.06-0.44 between 0 and 7 years; p < 0.001) with HA- compared with non-HA-coated stems, but this was observed after an early (< 6 months) higher risk of revision for any reason (HR, 2.88; 95% CI, 1.15-7.21; p = 0.024).

CONCLUSIONS

Overall, HA coating of femoral stems was found to be associated with a 17% lower risk of revision for any reason. However, the lower risk of revision associated with HA was not consistent for all prosthesis designs where both HA- and non-HA-coated femoral stem versions were available. Some HA-coated stems have higher revision rates compared with their non-HA-coated versions. Our findings suggest that the effect of HA coating on revision risk varies depending on prosthesis design.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Fracture of cobalt chrome, fully-coat beaded femoral revision long stem, a clinical outcomes study

Background

Femoral bone loss during revision total hip arthroplasty poses a challenging problem. Bypass fixation over the diaphysis has achieved clinical success in cases of proximal femoral bone loss. Fracture of cementless, fully bead-coated femoral stem is an uncommon complication. The purpose of this study is to analyze the patients with and without fracture stem and find out the possible risk factors.

Methods

From 2006 to 2012, a total of 251 revision long stems (Zimmer, Warsaw, IN) were implanted. In the same period, 17 broken stems that underwent treatment were included for analysis. Patients' demographic data, pattern of femoral bone loss, stem size, medial calcar support in the proximal region of the stem, and the timing of stem breakage were collected and analyzed.

Results

The stem size in patients with a broken stem was smaller (p < 0.001), and medial calcar defect was 12.4% and 100% (p < 0.001), respectively. The bone defect was greater in broken group (p = 0.024). The mean duration between revision surgery and stem breakage was 58.07 ± 36.98 months. Smaller stem size, greater bone defect, and inadequate medial calcar bone support were major risk factors for stem breakage.

Conclusions

Bypass fixation in the distal diaphysis with a long stem prosthesis without adequate bone support over medial calcar area may cause stress concentration in the long stem and a fatigue fracture. Use of a smaller prosthesis is the major risk of stem broken. It is essential to repair the proximal femoral bone deficiency and implant selection for better metaphyseal engagement to prevent further stem complications.

Level of evidence

Level III, case control study.

Fracture of Fully-coated Femoral Stem after Primary Total Hip Arthroplasty for Nonunion of Intertrochanteric Fracture: A Case Report

Femoral stem fracture is an uncommon reason for the failure of total hip arthroplasty, with only 16 cases of fully coated stem fractures reported to date. Here we report a case in which a fully coated primary femoral stem fracture occurred after conversion to total hip arthroplasty for the non-union of an intertrochanteric fracture of the femur. Metallurgic evaluation of the etiology and mechanism revealed that the fracture was initiated by fatigue-related failure and completed by ductile failure on the posterior side of the fracture. Considering the recent trend of treating an intertrochanteric fracture with hip arthroplasty, possible stem failure should be considered, since most patients will have at least one of the known risk factors for stem fracture.

Fracture of Uncemented Revision Femoral Stems in three Arthroplasty Patients: A Case Series with three different brands

INTRODUCTION

Fracture of stems in primary total hip arthroplasty is a known complication and has been attributed to varus positioning, excessive weight of the patient, resorption of the femoral calcar and failure of the cement mantle. Fractures in uncemented revision femoral stems are rare and are attributed to reduction in proximal support either in the form of bone loss or an extended trochanteric osteotomy [ETO] against a distally well- fixed stem. Also, undersized stems and high BMI to increase the risk of stem fracture.

CASE REPORT

We report 3 cases of uncemented revision stem fractures. Case 1 is a 77 year old male, Case 2 is a 71- year-old female, case 3 an 82-year-old male. All three patients had significant proximal femoral osteolysis. All three had an extended trochanteric osteotomy for the revision surgery. The hips had remained in-situ for 4, 2 and 5 years respectively prior to fracture.

CONCLUSION

When planning complex revision cases involving long uncemented stems, attention should be given to the above-mentioned variables. ETO non-union and proximal bone loss play an important role in stem fractures. Stem failure can occur irrespective of the make, and factors such as adequate stem size and good diaphyseal fit are non negotiable.

Rupture of Extensively Porous Coated Stems. - A Case Series of 2 Patients

Introduction:

Mechanical failure of femoral stems of revision hip arthroplasty has been rarely reported. In the current study, the cause of two stem fractures, which occurred in vivo, was analysed with use of clinical and radiological data, and the functional result after revision is presented.

Case Report:

Two patients, A 70-year-old male and a 73-year-old female, both of Mediterranean ethnic, and both patients underwent a revision total hip replacement to an uncemmented extensively porous coated stem. Both stems suffered an implant fatigue in vivo at three years and at two years follow-up respectively.

Conclusion:

Revision total hip arthroplasty is a procedure that will be performed more often the following years due to aging of population. Any orthopaedic surgeon performing hip surgery should be aware of the risk factors that can lead to total hip arthroplasty failure. In the analysed cases we can learn that the main factors related to this failure included the use of a small size stem (inferior to 14mm), an inadequate proximal osseous support because of trochanteric osteotomy, and a reduced preoperative bone stock. Although the use of cables has not been stated as a predisposing factor, we consider that they could also play a role in the development of this rare complication.