Periprosthetic femoral fracture as cause of early revision after short stem hip arthroplasty-a multicentric analysis

Outcomes of traumatic Vancouver type AG periprosthetic fractures treated nonoperatively

Introduction

The optimal treatment for postoperative Vancouver AG fractures has not been established. This study is a case series investigating the outcomes of patients from a single, academic tertiary referral center with conservative management of postoperative, traumatic periprosthetic fractures, specifically Vancouver type AG fractures.

Methods

This study was a retrospective review of 225 patients diagnosed with periprosthetic fracture at an academic, tertiary referral center from January 2007 to June 2023. Of these patients, 18 were identified as having Vancouver Type AG fractures and underwent conservative treatment with a walker. Radiographic fracture healing, patient reported pain, ambulatory status, and abductor strength were evaluated.

Results

All 18 patients included in this case series suffered from traumatic postoperative periprosthetic fractures from falls, and none were noted to have any concomitant osteolytic changes. Mean age at the time of fracture of 81.4, range (62-96). Mean BMI at the time of fracture was 24.1, range (18-38.1). 1 patient passed away from unrelated medical problems 3 months after fracture onset, 2 were lost to follow-up after emergency department (ED) discharge, 3 demonstrated healing, but not yet fully healed fractures at their last follow-up, and 3 patients presented to the ED at a much later time for non-orthopaedic related issues and demonstrated healed fractures on radiographic. For the remaining 9 patients, mean length of time to heal after onset of fracture was 14.2 weeks, range (6-44). No weakness was noted during their last follow-up, and only 1 patient noted residual 1 of 10 pain. 5 patients noted to using walkers, 3 using canes, and 1 interchanging between a walker and cane during the last follow-up.

Conclusion

Patients with minimally to nondisplaced Vancouver type AG can achieve fracture healing and pain resolution with conservative, protected weight-bearing management in the setting of postoperative trauma.

Does CT improve the accuracy of predicting implant fixation status for periprosthetic fractures around uncemented femoral components?

Aims

Periprosthetic femoral fractures (PPFFs) around total hip arthroplasty (THA) stems are challenging. Typically, loose stems are revised, while well-fixed implants undergo fracture open reduction and internal fixation. Determining implant fixation status preoperatively is important. The purpose of this study was to define the accuracy of predicting the status of preoperative stem fixation using radiography and CT.

Methods

A total of 24 patients with Vancouver B-type PPFF with preoperative radiography and CT scans were included. Patients with obviously loose implants (detached or subsided stem), fractures that occurred within 90 days of index THA, and cemented femoral components were excluded. Two fellowship-trained adult reconstruction surgeons and two traumatologists reviewed radiographs and predicted stem fixation status. They then evaluated CT scans, and fixation status was reassessed. Each surgeon undertook two evaluations one month apart. The correct response was determined by intraoperative findings. Interobserver and intraobserver reliability values were calculated, as well as validity.

Results

Overall, 15 implants (62.5%) were well-fixed and nine (37.5%) were loose. Radiography alone predicted correct fixation status in 53.1% of cases (102/192). When adding CT, correct predictions improved to 54.7% (105/192). Fixation status predictions were changed in 18.2% of cases (35/192) after reviewing CT scans: 8.3% (16/192) from correct to incorrect, and 9.9% (19/192) from incorrect to correct. Interobserver reliability ranged from poor to moderate agreement, and intraobserver reliability demonstrated moderate agreement for all raters. No difference in accuracy was noted between adult reconstruction or trauma surgeons.

Conclusion

The ability to predict fixation status for PPFFs around uncemented femoral components remains challenging. The addition of preoperative CT did not significantly improve accuracy. Intraoperative testing of femoral component fixation status is essential to determine if revision or fixation is appropriate. Preoperative CT for Vancouver B PPFF does not significantly improve accuracy in assessing stem fixation status compared with plain radiography.

Mechanical Effects of Offset and Length of the Cementless Stem for Initial Fixation to the Femur

Backgroud

Implants with different neck offsets for hip replacement surgery are now available from various implant manufacturers and have become a widely used option for achieving postoperative hip stability. This study aimed to compare the impact of neck offset on initial stem fixation and the mechanical effects of different stem lengths when using cementless stems.

Methods

We performed a finite element analysis using Mechanical Finder ver. 12.0. CAD models of the Profemur Preserve and Profemur TL cementless stems. Each stem was appropriately sized, and the von Mises stress was calculated. We defined micromotion as the relative displacement between the stem node and the surface of bone contact. The maximum micromotion values of these finite element models were compared under standing conditions.

Results

The stress per zone for both stems (Preserve and TL) was the highest in zone 5, followed by zones 3 and 4, which were almost in line with each other. The high offset (HIGH) stress was higher than the standard offset (STD) stress in each stem and zone. The micromotion of each stem was higher at each load in the following order: Preserve HIGH, Preserve STD, TL HIGH, and TL STD, with HIGH being higher than STD at each stem.

Conclusions

The choice of higher offset or shorter length stems induced higher micromotion at the interface to the bone in the early postoperative period. Therefore, surgeons should be more careful to get appropriate initial fixation using shorter stems with higher offset necks due to the relatively high incidence of loosening or fractures.

Long-term results of short stem total hip arthroplasty in patients with osteonecrosis of the femoral head

INTRODUCTION

Short stem total hip arthroplasty (THA) is an alternative to conventional stem, designed to facilitate minimal-invasive surgery, physiological loading and preserve bone stock. However, there is insufficient evidence of the long-term outcomes in patients with osteonecrosis of the femoral head (ONFH). This study aims to analyze the clinical and radiographic results with a minimum follow-up of 10 years. Furthermore, the survival rate of the short stem was calculated.

MATERIALS AND METHODS

There were 81 patients (101 hips) with the mean age of 45 years (range, 21 to 68) in this study. The Harris Hip Scores (HHS) and Forgotten Joint Scores (FJS) were recorded to evaluate the clinical results. The appearance of osteointegration and radiolucent line were reviewed. The mean follow-up period was 129.3 months (range, 120-154).

RESULTS

At the latest follow-up, the mean HHS and FJS were 96.9 ± 5.7 (range, 69-100) and 95 ± 7 (range, 75-100) points respectively. The radiographic changes around the stem showed osteointegration mainly in the proximal part, zones 1 (94.1%), 2 (84.2%), 6 (99%) and 7 (92.1%). One stem underwent revision due to periprosthetic fracture, using conventional stem with plate and screws. Survivorship of the stem with the endpoint for any reason was 99.01% (95% confidence interval [CI], 93.18-99.86%) and for aseptic loosening was 100% at 10 years.

CONCLUSION

Short stem showed promising long-term clinical outcomes in patients with ONFH. The radiographic results demonstrated physiological proximal load transfer.

Risk Factors for Periprosthetic Femoral Fractures After Cementless Total Hip Arthroplasty

BACKGROUND

The present study aimed to identify the risk factors of periprosthetic femoral fracture (PFF) after cementless total hip arthroplasty and rank them based on importance.

METHODS

The age, sex, body mass index (BMI), osteoporosis, canal flare index (CFI), canal bone ratio (CBR), canal calcar ratio (CCR), stem design, and stem canal fill ratio (P1, P2, P3, and P4) of the proximal femoral medullary cavity of 111 total hip arthroplasty patients who had PFF and 388 who did not have PFF were analyzed. Independent-samples student t-tests were used for continuous variables, and Chi-square tests were used for categorical variables. The importance rankings of influencing factors were assessed using a random forest algorithm. Dimensionally reduced variables were then incorporated into a binary logistic regression model to determine the PFF-related risk factors.

RESULTS

The mean age, BMI, CBR, CCR, and incidence of osteoporosis were higher in cases of PFF (all P < .001), while the mean CFI, P1, P2, P3, and P4 were lower in cases of PFF (P < .001, P = .033, P = .008, P < .001, and P < .001, respectively). Additionally, the stem design was also statistically associated with PFF (P < .001). Multivariate logistic regression revealed that advanced age, higher BMI, osteoporosis, stem design, lower CFI, higher CBR, higher CCR, lower P1, lower P2, lower P3, and lower P4 were the risk factors of PFF (P < .001, P < .001, P < .001, P < .001, P < .001, P = .010, P < .001, P = .002, P < .001, P < .001, and P = .007, respectively). The ranked importance of the risk factors for PFF was P3, CFI, osteoporosis, CBR, age, P4, P1, stem design, CCR, BMI, and P2.

CONCLUSIONS

Lower P3, lower CFI, osteoporosis, higher CBR, advanced age, lower P4, lower P1, stem design, higher CCR, higher BMI, and lower P2 increased the risk of PFF.

Periprosthetic fracture following arthroplasty for femoral neck fracture: is a cemented stem protective?

BACKGROUND

Periprosthetic femoral fractures (PFF) carry significant morbidity following arthroplasty for femoral neck fracture (FNF). This study assessed fracture complications following arthroplasty for FNF and the effect of cement fixation of the femoral component on intraoperative and post-operative PFF.

METHODS

Between February 2014 and September 2021, 740 patients with a FNF who underwent arthroplasty were analyzed for demographics, surgical management, use of cement for fixation of the femoral component, and subsequent PFF. Variables were compared with Mann-Whitney or Chi-square as appropriate. Multivariate logistic regression was used to assess independent risk factors associated with intraoperative or post-operative PFF.

RESULTS

There were 163 THAs (41% cemented) and 577 HAs (95% cemented). There were 28 PFFs (3.8%): 18 post-operative and 10 intraoperative. Fewer post-operative PFFs occurred with cemented stems (1.63% vs. 6.30%, p = 0.002). Mean time from surgery to presentation with post-operative PFF was 14 months (0-45 months). Mean follow-up time was 10.3 months (range: 0-75.7 months). In multivariate regression, use of cement and THA was independently associated with decreased post-operative PFF (cement: OR 0.112, 95% CI 0.036-0.352, p < 0.001 and THA: OR 0.249, 95% CI 0.064-0.961, p = 0.044). More intraoperative fractures occurred during THA (3.68% vs. 0.69%, p = 0.004) and non-cemented procedures (5.51% vs. 0.49%, p < 0.001). In multivariate regression, use of cement was protective against intraoperative fracture (OR 0.100, CI 0.017-0.571, p = 0.010).

CONCLUSIONS

In patients with a FNF treated with arthroplasty, cementing the femoral component is associated with a lower risk of intraoperative and post-operative PFF. Choice of procedure may be based on patient factors and surgeon preference.

Rectangular Taper Stem Designs Are Associated With a Higher Risk for Periprosthstic Femoral Fractures After Cementless Total Hip Arthroplasty

BACKGROUND

Periprosthetic femoral fractures (PFFs) remain a major concern following cementless total hip arthroplasty (THA). This study aimed to evaluate the association between different types of cementless tapered stems and the risk of postoperative PFF.

METHODS

A retrospective review of primary THAs performed at a single center from January 2011 to December 2018 included 3,315 hips (2,326 patients). Cementless stems were classified according to their design. The incidence of PFF was compared between flat taper porous-coated stems (type A), rectangular taper grit-blasted stems (type B1), and quadrangular taper hydroxyapatite-coated stems (type B2). Multivariate regression analyses were performed to identify independent factors related to PFF. The mean follow-up duration was 61 months (range, 12 to 139). Overall, 45 (1.4%) postoperative PFFs occurred.

RESULTS

The incidence of PFF was significantly higher in type B1 stems than in type A and type B2 stems (1.8 versus 0.7 versus 0.7%; P = .022). Additionally, more surgical treatments (1.7 versus 0.5 versus 0.7%; P = .013) and femoral revisions (1.2 versus 0.2 versus 0%; P = .004) were required for PFF in type B1 stems. After controlling for confounding variables, older age, diagnosis of hip fracture, and use of type B1 stems were significant factors associated with PFF.

CONCLUSION

Type B1 rectangular taper stems were found to have higher risks for postoperative PFF and PFF requiring surgical management than type A and type B2 stems in THA. Femoral stem geometry should be considered when planning for cementless THA in elderly patients who have compromised bone quality.

Varus malalignment of short femoral stem not associated with post-hip arthroplasty fracture

INTRODUCTION

Periprosthetic femoral fractures are an increasingly common post-operative complication of total hip arthroplasty (THA). Though varus malalignment is known to increase fracture risk in standard-length femoral stems, varus malalignment is not as well studied in short stems. Therefore, the purpose of this study was to determine if varus malalignment contributes to early periprosthetic fracture risk in a cementless taper-wedged, short femoral stem.

MATERIALS AND METHODS

This retrospective review included 366 consecutive patients (441 THAs) having undergone THA via anterior approach by a single surgeon between July 2014 and December 2016. All patients received the same short, cementless femoral stem. Femoral component angle was measured on 6-week post-THA weight-bearing radiographs, with malalignment defined as a femoral component angle exceeding 0° ± 3°. Periprosthetic femoral fracture and aseptic loosening occurring within 2 years post-THA were recorded.

RESULTS

The final data analysis included 426 hips with a mean follow-up time of 32.9 ± 10.2 months. Varus and neutral alignment occurred in 84 (19.6%) and 342 (79.9%) of stems, respectively. Three (0.7%) periprosthetic femoral fractures occurred within 2 years, all occurring in patients with neutrally aligned femoral stems. One (0.2%) stem failed due to aseptic loosening and was malaligned.

CONCLUSION

Despite nearly 20% of stems placed in varus alignment, three of the four early complications occurred in a neutrally aligned stem. Based on these results, forceful intraoperative realignment of a short femoral stem with good initial fixation may present an unnecessary increased risk of intraoperative fracture.

Does femoral stem choice influence fracture type or incidence for direct anterior approach total hip arthroplasty?

INTRODUCTION

Despite similar fracture rates, the incidence of intraoperative and post-operative fractures between standard (ST) length and short (SH) femoral stems remains unclear. Therefore, this study compared the incidence of intraoperative and early postoperative fractures between three ST and a single tapered-wedge SH femoral stem.

MATERIALS AND METHODS

Data were retrospectively collected on 1113 patients (1306 hips) having undergone total hip arthroplasty, via the anterior approach on a fracture table, between 2014 and 2019. One surgeon completed all ST procedures (314 hips), using one of three implants without discretion. One surgeon completed all SH procedures (992 hips), using one implant design. Differences between ST and SH groups were evaluated by independent t tests (continuous variables) and Chi-square tests (categorical variables).

RESULTS

Patients in the SH group were significantly older (p < 0.001) and had a lower body mass index (p = 0.001) compared to the ST group. The total number of fractures was 12 (3.8%) and 14 (1.4%) in the ST and SH groups, respectively. The 12 ST fractures occurred intraoperatively, compared to two (0.2%) in the SH group. The remaining seven (0.7%) SH fractures occurred post-operatively. There was no difference in fracture rate between the three ST designs (p = 0.882). Interestingly, five (0.5%) insufficiency fractures were diagnosed in the SH group.

CONCLUSION

The risk of intraoperative and post-operative fractures following anterior total hip arthroplasty may be biased toward ST and SH implants, respectively. These results, along with the presence of five insufficient fractures, identify potential fracture risks and mechanisms for specific implant designs.

Current Trends in Revision Hip Arthroplasty: Indications and Types of Components Revised

BACKGROUND

The materials and techniques for both primary and revision total hip arthroplasty (THA) have changed over time. This study evaluated if the indications for revision THA, rates of components utilized (femoral or acetabulum, both, or head/liner exchange), length of stay (LOS), and payments to surgeons and facilities have also changed.

METHODS

A retrospective study, utilizing the PearlDiver database, of 38,377 revision THA patients from January 2010 through December 2018 was performed. Data included the indication for revision, components revised (femoral or acetabulum, both, or head/liner exchange), LOS, and payments. Indications and components were analyzed by logistic regression (Dunnett's post hoc test). Revision totals were analyzed with a linear regression model. Analysis of variance assessed changes in LOS and payments.

RESULTS

Patients' median age was 67 years (Q1-Q3: 59-74), and 58.7% were female. Revisions for dislocation decreased between 2010 and 2018 (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.68-0.98). Revisions for component loosening increased (OR 1.54, 95% CI 1.25-1.91). Dislocation remained the most common indication (19.3%), followed by PJI (17.3%) and loosening (17.1%). Both-component (OR:1.45; 95% CI:1.25-1.67) and femoral component only revisions increased; acetabular component only and head/liner exchanges decreased. Acetabular (OR 0.57, 95% CI 0.47-0.70) and head/liner exchange (OR 0.29, 95% CI 0.20-0.43) revisions decreased, while both component exchange (OR 1.45, 95% CI 1.25-1.67) and femoral revisions (OR 1.17, 95% CI 0.99-1.37) increased. Average LOS (-0.68 days; P < .001) and surgeon payments decreased (-$261.8; P < .001) while facility payments increased ($4,211; P < .001).

CONCLUSION

Indications for revision THA in this database study changed over time, with revision for dislocation decreasing and revision for loosening increasing over time. Both component and femoral revisions increased, and acetabular component and head/liner exchanges decreased. It is possible that these associations could be attributed to a number of details, the method of femoral fixation, surgical approach, and cementing, all of which require additional study.

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.

French Hip & Knee Society classification of short-stem hip prostheses: Inter- and intra-observer reproducibility

INTRODUCTION

In total hip replacement (THR), a short stem theoretically provides more physiological force transfer to the proximal femur, conserves bone stock and facilitates minimally invasive surgery. On the other hand, such implants involve a learning curve and incur risk of malpositioning or fracture and of secondary mobilization. There are several types of short stem, and classification is needed. Classifications exist, but are based more on implant length than on anchorage zone, and most have not been tested for reproducibility. The French Hip & Knee Society (SFHG) developed a short-stem classification based on anchorage zone inside the femur. The objectives of the present study were: (1) to present the classification, (2) to apply it to the short-stem models available in France and those widely used worldwide, and (3) to assess reproducibility.

HYPOTHESIS

The SFHG short-stem classification enables reproducible comparison.

MATERIAL AND METHOD

A short-stem classification according to anchorage zone was drawn up by an expert group. The stems and the classification were presented to 12 surgeons performing THR, who classified the stems according to the classification; a retest was performed 2 months later.

RESULTS

The classification is based on femoral stem anchorage site, in 5 types: type 1, cephalic; type 2, isolated cervical; type 3, Calcar femorale; type 4, metaphyseal; and type 5, conventional metaphyseal-diaphyseal, with shortened stems. Inter-observer reproducibility was 92.7% [95%CI: 91.7%-93.6%], with kappa 0.785 [95%CI: 0.755-0.814], and Lin test-rest concordance correlation coefficient 0.852 [95%CI: 0.836-0.869]. Intra-observer reproducibility was 94.0% [95%CI: 91.9%-96.1%], with kappa 0.820 [95%CI: 0.759-0.882], and Lin test-retest concordance correlation coefficient 0.820 [95%CI: 0.792-0.849].

DISCUSSION

This new classification enables femoral implants to be reproducibly compared according to anchorage zone.

LEVEL OF EVIDENCE

IV; retrospective study without control group.

Revision hip arthroplasty using a porous tantalum acetabular component

INTRODUCTION

Reconstruction of acetabulum in case of bone defects can be challenging. The aim of this retrospective study was to investigate the 10-year survival of trabecular tantalum metal (TM) acetabulum component in revision hip arthroplasty operations and to evaluate complications.

METHODS

A total of 100 consecutive acetabulum revision hip arthroplasties (100 patients) were operated on between May 2004 and October 2006 at Kuopio University Hospital. The mean follow-up time was 9.4 years and the median was 11.5 years (SD 4.118; range 0.1-13.4 years). Kaplan-Meier survival analysis was performed to study the survival of patients to re-revision surgery. Intra- and postoperative complications and reasons for re-revision were evaluated.

RESULTS

The Kaplan-Meier analysis showed a cumulative proportion of revision hip survivorship of 66% at 13.4 years (SE 0.403, 95% CI, 10.886-12.466) based on the need for further re-revision surgery for any major reason. The Kaplan-Meier survival analysis of time to re-revision surgery due acetabular component loosening showed a cumulative proportion of survivorship of 98.9% at 13.4 years (SE 0.136; 95% CI, 12.998-13.529). There were a total of 41/100 complications and the most common complication was dislocation (24/100). Re-revision for any major reason was performed on 18/100 of the revision arthroplasties. The mean time to re-revision was 4.9 years (SD 5.247; range 0.1-13.2 years).

DISCUSSION

The trabecular TM acetabular component gives excellent outcomes regarding stability and fixation to the acetabulum in acetabulum revision hip arthroplasty at a minimum of ten years of follow-up. However, acetabular component malposition and the small head size (28 mm) are risk factors for dislocation.

Reduction of Periprosthetic Proximal Femur Fracture in Direct Anterior Total Hip According to Stem Design

The direct anterior approach (DAA) is gaining popularity in primary total hip arthroplasty (THA). Although DAA has demonstrated many advantages over other surgical approaches, periprosthetic femur fractures (PPFF) rates continue to be higher. Femoral stem designs that allow for easier insertion via a DAA may contribute to the higher rates of fracture seen in this approach. Certain stem designs and fixation methods may reduce the risk of PPFF via a DAA in primary THA.

Multiple failures of internal fixation for treatment of periprosthetic femoral refracture: a case report and literature review

We herein report a case involving three failures of internal fixation after periprosthetic femoral fracture (Vancouver type B1). The patient had low bone mass (T-score of −1.7) and was overweight (body mass index of 28.7 kg/m²) but had no sign of femoral stem loosening. The first open reduction with internal fixation was performed according to the recommended treatment. Unexpectedly, three treatment failures subsequently occurred, after which the patient finally attained endurable walking activity. A literature review indicated that the intrinsic biomechanical problems of Vancouver B1 fractures have not been thoroughly addressed. Choosing the correct surgical strategy for Vancouver B1 fractures is essential to avoid complications and ensure healing. A sufficient locking plate and cable system should be used after the first failure if revision was not performed the first time.

Effect of stem position and length on bone-stem constructs after cementless hip arthroplasty

Aims

There are concerns regarding initial stability and early periprosthetic fractures in cementless hip arthroplasty using short stems. This study aimed to investigate stress on the cortical bone around the stem and micromotions between the stem and cortical bone according to femoral stem length and positioning.

Methods

In total, 12 femoral finite element models (FEMs) were constructed and tested in walking and stair-climbing. Femoral stems of three different lengths and two different positions were simulated, assuming press-fit fixation within each FEM. Stress on the cortical bone and micromotions between the stem and bone were measured in each condition.

Results

Stress concentration was observed on the medial and lateral interfaces between the cortical bone and stem. With neutral stem insertion, mean stress over a region of interest was greater at the medial than lateral interface regardless of stem length, which increased as the stem shortened. Mean stress increased in the varus-inserted stems compared to the stems inserted neutrally, especially at the lateral interface in contact with the stem tip. The maximum stress was observed at the lateral interface in a varus-inserted short stem. All mean stresses were greater in stair-climbing condition than walking. Each micromotion was also greater in shorter stems and varus-inserted stems, and in stair-climbing condition.

Conclusion

The stem should be inserted neutrally and stair-climbing movement should be avoided in the early postoperative period, in order to preserve early stability and reduce the possibility of thigh pain, especially when using a shorter stem.

Cite this article: Bone Joint Res 2021;10(4):250–258.

Complex Primary Total Hip Arthroplasty: Small Stems for Big Challenges

Total hip arthroplasty is one of the most successful operations in all of medicine. Femoral deformities from malunion, prior osteotomy, and retained surgical implants all present unique challenges. Corrective osteotomy and hardware removal add significant morbidity to an operation that typically has a fast recovery. Short stems can be used in these cases to spare patients' increased morbidity. We present a case-based illustration and surgical technique for the use of short stems in complex primary total hip arthroplasty with femoral deformity and retained hardware. We discuss how these implants can spare significant morbidity, show radiographic examples of their use, and present short-term outcomes.

Computed tomography for managing periprosthetic femoral fractures. A retrospective analysis

Background

Periprosthetic fractures (PPF) present a common cause for revision surgery after arthroplasty. The choice of performing either an osteosynthesis or revision arthroplasty depends on the orthopedic implant anchored and loosening. Standard diagnostics include x-ray imaging. CT is usually performed to confirm implant loosening in case of ambiguous diagnosis on standard x-ray imaging. This study aimed to examine the role of CT as a diagnostic modality and its implications for treatment planning and outcome.

Methods

Patients treated for PPF from January 2010 to February 2018 were included. X-ray and CT reports were analyzed to assess implant loosening. The planning for surgery and the final surgical treatment were evaluated. In addition, patient characteristics were analyzed and compared between patients with and without additional CT as a preoperative diagnostic procedure.

Results

Seventy-five patients were eligible for the study. X-ray imaging was performed in 90.7% of cases. CT was performed in 60% of the cases as part of the preoperative diagnostic. A clear statement on implant stability or loosening could not be made in 69.1% after X-ray imaging and in 84.4% following CT imaging. Revision arthroplasty for loosened femoral prosthesis components was necessary in 40% of cases. No difference could be determined comparing patients with X-ray imaging to those with X-ray and additional CT. In both groups, operative treatment did not deviate from the preoperative planning.

Discussion

In two thirds of the conventional radiographic findings, no reliable evaluation of implant loosening was possible in femoral PPFs. Intriguingly, additional CT did not improve the evaluation of implant loosening. Nonetheless, CT scans are often performed if loosening assessment is unclear on regular radiographs. This fact can explain the bias CT results in comparison to regular radiography. However, software-supported CT diagnosis could help to adequately answer the question of loosened implants in PPF in the near future. Since the diagnosis of fracture and their morphology assessment is currently adequately performed using X-rays, CT shall not be considered as the gold standard.

Incidence and pattern of periprosthetic hip fractures around the stem in different stem geometry

BACKGROUND

The number of total hip arthroplasties (THA) is expected to increase worldwide; thus, complications are likely to increase at the same ratio. In this scenario, periprosthetic femoral fractures (PFFs) are an increasing concern. Identifying the predisposing factors is important in order to prevent as much as possible the risk of PFF in the future.

PATIENTS AND METHODS

The purpose of this study was to correlate the risk of periprosthetic femoral fractures to the most common patients' comorbidities and stem geometry. We reviewed all THA for non-oncologic indications between 2004 and 2014 with a mean follow-up of six years (range, 2-12). Three thousand two hundred forty-eight patients (3593 implants) were enrolled in the study, and 45 PFF were registered during this time period. Two thousand five hundred seventy-seven implants (71%) were straight stems, and 1015 (28.3%) were anatomic stems. All X-rays were then analyzed and classified according to the modified Vancouver classification.

RESULTS

Periprosthetic femoral fractures incidence was associated with anatomic stem geometry (p < 0.001, OR = 2.2), BMI (p < 0.001), and diabetes (p < 0.001, OR = 5.18). PFFs were not significantly associated with age, gender, and all the other variables. Fracture pattern was different between straight and anatomic stems. Clamshell fractures were more likely to occur in anatomic stems compared to straight stems (p < 0.005).

CONCLUSIONS

Periprosthetic femoral fractures are highly associated with obesity and osteoporosis. Anatomic stems reported a higher incidence of PPF than straight stems. The typical fracture type for anatomical stems is the clamshell pattern, while straight stems are more likely affected by type B fractures.

Cementless short-stem total hip arthroplasty in the elderly patient - is it a safe option?: a prospective multicentre observational study

Background

Due to its bone preserving philosophy, short-stem total hip arthroplasty (THA) has primarily been recommended for young and active patients. However, there may be benefits for elderly patients given a less invasive operative technique due to the short curved implant design. The purpose of this study was to compare the clinical and radiological outcomes as well as perioperative complications of a calcar-guided short stem between a young (< 60 years) and a geriatric (> 75 years) population.

Methods

Data were collected in a total of 5 centers, and 400 short-stems were included as part of a prospective multicentre observational study between 2010 and 2014 with a mean follow-up of 49.2 months. Preoperative femur morphology was analysed using the Dorr classification. Clinical and radiological outcomes were assessed in both groups as well as perioperative complications, rates and reasons for stem revision.

Results

No differences were found for the mean visual analogue scale (VAS) values of rest pain, load pain, and satisfaction, whereas Harris Hip Score (HHS) was slightly better in the young group. Comparing both groups, none of the radiological parameters that were assessed (stress-shielding, cortical hypertrophy, radiolucency, osteolysis) reached differences of statistical significance. While in young patients aseptic loosening is the main cause of implant failure, in the elderly group particularly postoperative periprosthetic fractures due to accidental fall have to be considered to be of high risk. The incidence of periprosthetic fractures was found to be 0% in Dorr type A femurs, whereas in Dorr types B and C fractures occurred in 2.1 and 22.2% respectively.

Conclusions

Advanced age alone is not necessarily to be considered as contra-indications for calcar-guided short-stem THA, although further follow-up is needed. However, markedly reduced bone quality with femur morphology of Dorr type C seems to be associated with increased risk for postoperative periprosthetic fractures, thus indication should be limited to Dorr types A and B.

Trial registration

German Clinical Trials Register; DRKS00012634, 07.07.2017 (retrospectively registered).

A new classification for proximal femur bone defects in conservative hip arthroplasty revisions

INTRODUCTION

In the last three decades, total hip replacement in young patient became a habitual procedure. Principles of bone preservation are pushing many surgeons to implant conservative femoral components in patient younger than 65 years. Despite an overall good survivorship and clinical outcomes of conservative implants, failed cases are reported and the need to revise a conservative femoral component became an occasional procedure (with high prevalence of failed resurfacing implants).

METHODS

During conservative femoral component revisions, we analyzed proximal bone stock preservation, considering the type of original component removed, etiology of failure, timing of revision, and femoral explantation technique.

RESULTS

We identified four patterns of proximal femoral changes (types I-IV). We suggest, for each of them, a revision strategy directed toward a "conservative revision procedure" using conservative or primary component. Out of our 21 cases, none underwent further revision due to mechanical failure (follow-up ranging from 6 to 152 months, mean 54 months). We had two case of re-operation: one for early septic loosening and one for prosthetic modular neck fracture.

CONCLUSIONS

If literature offers well-established guidelines to femoral revision of conventional stems, there is, on the other hand, a lack of data about revision strategies in presence of failed conservative implants. Although the mean follow-up of our procedures is still too short (4.5 years) to give final conclusions, we would leave a message: a conservative hip arthroplasty is not a "one-time" opportunity for young and active people. A "conservative revision" is a valid option for at least a part of them, when an early failure of primary procedure occurred.

A new classification for proximal femur bone defects in conservative hip arthroplasty revisions

INTRODUCTION

In last three decades, total hip replacement in young patients became an habitual procedure. Principles of bone preservation are pushing many surgeons to implant conservative femoral components in patient younger than 65 years. Despite an overall good survivorship and clinical outcomes of conservative implants, failed cases are reported and the need to revise a conservative femoral component became an occasional procedure (with high prevalence of failed resurfacing implants).

METHODS

During conservative femoral component revisions, we analyzed proximal bone stock preservation, considering the type of original component removed, aetiology of failure, timing of revision, and femoral explantation technique.

RESULTS

We identified four patterns of proximal femoral changes (types I-IV). We suggest, for each of them, a revision strategy directed toward a "conservative revision procedure" using conservative or primary component. Out of our 21 cases, none underwent further revision due to mechanical failure (follow-up ranging from 6 to 152 months, mean 54 months). We had two cases of re-operation: one for early septic loosening and one for prosthetic modular neck fracture.

CONCLUSIONS

If literature offers well-established guidelines to femoral revision of conventional stems, there is, on the other hand, a lack of data about revision strategies in presence of failed conservative implants. Although the mean follow-up of our procedures is still too short (4.5 years) to give final conclusions, we would leave a message: a conservative hip arthroplasty is not a "one time" opportunity for young and active people. A "conservative revision" is a valid option for at least a part of them, when an early failure of primary procedure occurred.

Fourteen-year experience with short cemented stems in total hip replacement

PURPOSE

The age of the population requiring total hip replacement (THR) is increasing and this may lead to a return of cemented stems. Advantages of a short cemented femoral device include preservation of metaphyseal bone, easier insertion, and easier cement removal in case of revision. The purpose of this study is to describe the rationale and assess midterm results of unique innovative short cemented double-tapered polished stem applied with contemporary cementing techniques.

METHODS

Our experience with this short cemented stem includes two different groups of elderly patients. Group 1 (prototype version of the short stem) from January 2005 to January 2008 counts 43 THR. Group 2 (final commercial version of the short stem) from January 2013 to January 2015 counts 54 THR. The average age in groups 1 and 2 was 79 and 75 respectively. Patients underwent clinical follow-up with the Harris Hip Score (HHS) and completed radiographic evaluation.

RESULTS

Thirty-one patients of group 1 had died for reasons unrelated to their THR. The surviving 9 hips have a follow-up of 11.2 years. In group 2, eight  patients died for reasons unrelated to their THR. Follow-up for the surviving 40 patients is 4.6 years. HHS improved in both groups. In 34/43 hips of group 1 and in 41/54 of group 2 we observed a Barrack grade A cement mantle. Survival with revision of the stem for aseptic loosening as the endpoint was 100%.

CONCLUSIONS

This study confirms the effectiveness of a short, polished, collarless, tapered cemented stem implanted with contemporary cementing techniques which appears as successful as the standard sized components.

Development of periprosthetic bone mass density around the cementless Metha® short hip stem during three year follow up-a prospective radiological and clinical study

PURPOSE

The purpose of this study was to check the concept of the cementless Metha® short hip stem in order to find out whether proximal physiological load transfer can be achieved.

METHODS

Fourty-three patients were included. Epidemiological factors were established. The Harris Hip Score was determined and measurement of bone mass density as well as osteodensitometric and radiological measurements was carried out pre-operatively, post-operatively, and after six, 12, 24, and 36 months.

RESULTS

Harris Hip Score improved from 55.9 ± 12.4 pre-operatively to 94.8 ± 8.2 after 36 months (p < 0.001). After initial reduction of bone density in zones 1 and 7 up to six months post-operatively, there was a steady approximation of bone density to the initial values (p < 0.05).

CONCLUSION

The Metha® short hip stem shows good clinical results. Furthermore, there is an increase of bone density in the proximal zones 1 and 7 between six and 36 months serving as a sign of physiological load transfer.