High risk of early periprosthetic fractures after primary hip arthroplasty in elderly patients using a cemented, tapered, polished stem

Evidence for cemented TKA and THA based on a comparison of international register data

BACKGROUND

Hip and knee implants can either be fixed without cement, press-fit, or with bone cement. Real-world data from arthroplasty registers, as well as studies provide a broad database for the discussion of cemented versus uncemented arthroplasty procedures.

OBJECTIVE

What does current evidence from international arthroplasty registries and meta-analyses recommend regarding cemented or cementless fixation of hip and knee implants?

METHODS

A recommendation is generated by means of direct data comparison from the arthroplasty registries of eight countries (USA, Germany, Australia, UK, Sweden, Norway, New Zealand, Netherlands), the comparison of 22 review studies and meta-analyses based on registry data, as well as an evaluation of recommendations of healthcare systems from different nations. For this purpose, reviews and meta-analyses were selected where the results were statistically significant, as were the annual reports of the arthroplasty registries that were current at the time of writing.

RESULTS

For knee arthroplasties, long survival time as well as lower risk of revision can be achieved with the support of cemented fixation with antibiotic-loaded bone cement. In patients aged 70 years and older, cemented fixation of hip stem implants significantly reduces risk of intraoperative or postoperative periprosthetic fracture (quadruple). This applies both to elective total hip arthroplasties and to hemiarthroplasty after femoral neck fractures. Antibiotic-loaded bone cement significantly (p = 0.041) reduces the risk of periprosthetic infection, especially in patients with femoral neck fractures.

CONCLUSION

Total knee replacement with antibiotic-loaded bone cement is well established internationally and is evidence-based. Registry data and meta-analyses recommend cemented fixation of the hip stem in older patients. In Germany, USA and Australia these evidence-based recommendations still must be transferred to daily practice.

Experience of an anatomic femoral stem in a UK orthopaedic centre beyond 20 years of follow-up

INTRODUCTION

Increasing interest in the use of anatomical stems has developed as the prevalence of periprosthetic fractures (PPFs) continues to increase. The primary aim of this study was to determine the long-term survivorship and PPF rate of an anatomical femoral stem in a single UK centre.

PATIENTS AND METHODS

Between 2000 and 2002, 94 consecutive THAs were performed using the 170 mm Lubinus SP II anatomical femoral stem in our institution. Patient demographics, operative details and clinical outcomes were collected prospectively in an arthroplasty database. Patient records and national radiographic archives were reviewed finally at a mean of 21.5 years (SD 0.7) following surgery to identify occurrence of subsequent revision surgery, dislocation or periprosthetic fracture.

RESULTS

Mean patient age at surgery was 65.8 years (SD 12.5, 34-88 years). There were 48 women (51%). Osteoarthritis was the operative indication in 88 patients (94%). Analysis of all-cause THA failure demonstrated a survivorship of 98.5% (95% confidence interval [CI], 98.0-99.3%) at 10 years and 96.7% (94.5-98.9%) at 21 years. The 20-year stem survival for aseptic loosening was 100% with no cases of significant lysis found (lucent line > 2 mm) and no stems required revision. Patient demographics did not appear to influence risk of revision (p > 0.05). There were 2 revisions in total (2 for acetabular loosening with original stems retained). There were no PPFs identified at mean 21.5 year follow-up and 5 dislocations (5%).

CONCLUSIONS

The Lubinus SP II 170 mm stem demonstrated excellent survivorship and negligible PPF rates over 20 years following primary THA.

Risk factors for periprosthetic femoral fracture risk around a cemented polished taper-slip stem using an osteoporotic composite bone model

This biomechanical study aimed to determine if variations in stem material, stem geometry, stem offset and cement viscosity affect mechanical resistance to postoperative periprosthetic fracture (PFF) after hip arthroplasty with a commonly used cemented polished taper-slip (PTS) stem (CPT, Zimmer Biomet) in a novel osteoporotic composite femoral bone model. Thirty-six osteoporotic composite femoral models were tested using a standardised in-vitro loading technique to simulate a typical PFF. Outcome measures were torque to failure (N), fracture energy (N/m2) and rotation to failure (°). Comparisons were made by stem material (cobalt chrome vs stainless steel), stem geometry (CPT stem vs Exeter stem), stem offset (standard offset vs extra extended offset) and cement viscosity (high viscosity vs low viscosity). Statistical comparisons were carried out with significance set at p < 0.05. All tested samples produced clinically representative fracture patterns with varying degrees of bone and cement comminution. There was no statistically significant difference in torque to failure, fracture energy or rotation to failure between any of the compared variables (all p > 0.05). This is the first biomechanical study on mechanical resistance to PFF using osteoporotic composite bone models. For the CPT stem, it confirms that stem material, stem offset, stem geometry and cement viscosity do not affect mechanical resistance to PFF in an osteoporotic bone model.

[Register data on cemented arthroplasty : A proof for cementless fixation?]

BACKGROUND

Hip and knee implants can be either fixated without cement, press-fit, or with bone cement. Real-world data from arthroplasty registers, as well as studies, provide a broad database for the discussion of cemented versus uncemented arthroplasty procedures.

OBJECTIVES

What is the recommendation for cemented or cementless anchorage of hip and knee implants based on the current evidence from international arthroplasty registries and meta-analyses?

METHODS

A recommendation is generated by means of a direct comparison of data from the arthroplasty registries of eight different countries (USA, Germany, Australia, UK, Sweden, Norway, New Zealand, and The Netherlands), the comparison of 22 review studies and meta-analyses based on registry data, as well as the evaluation of the recommendation of healthcare systems of different nations. For this purpose, reviews and meta-analyses whose results were statistically significant were selected, as were the annual reports of the arthroplasty registries that were current at the time of writing.

RESULTS

For knee endoprostheses, a long survival time, as well as a lower risk of revision can be achieved with the help of cemented anchorage with antibiotic-laden bone cement. In patients aged 70 years and older, cemented anchorage of the hip stem implant significantly reduces the risk of intraoperative or postoperative periprosthetic fracture (times four), this applies both to elective total hip arthroplasties (TEPs) and to hemiarthroplasty after femoral neck fractures. Antibiotic-loaded bone cement significantly (p = 0.041) reduces the risk of periprosthetic infection, especially in patients with femoral neck fractures.

CONCLUSIONS

Total knee replacement with antibiotic-loaded bone cement is well established in Germany and evidence based. Registry data and meta-analyses recommend cemented fixation of the hip stem in older patients-in Germany the evidence-based recommendations must still be transferred to daily practice.

Evaluation of Clinical and Radiological Outcomes in the Management of Intracapsular Fracture Neck of Femur in Elderly Treated With Cemented Bipolar Prosthesis

INTRODUCTION

Hip fractures, including femoral neck fractures (FNFs), represent a significant health challenge globally. Fractures of the hip can be categorized as either intracapsular or extracapsular. Among the elderly, FNFs are particularly prevalent and account for approximately half of all hip fractures.

AIM

This study aimed to evaluate the clinical and radiological outcomes of intracapsular FNFs in the elderly treated with cemented bipolar prostheses.  Objectives: This study aims to: (i) assess the clinical outcomes, including pain relief, functional mobility, and patient satisfaction, in elderly individuals with intracapsular FNFs treated with cemented bipolar prosthesis; (ii) examine the radiological outcomes of intracapsular FNFs in the elderly following treatment with cemented bipolar prosthesis, focusing on factors such as implant stability, fracture healing, and any signs of complications.

METHODS

A prospective study included elderly patients (aged 55 and above) with intracapsular FNFs treated with cemented bipolar prostheses. Data were collected using a structured proforma, and outcomes were assessed through clinical and radiological evaluations at regular follow-ups.

RESULTS

The study included 60 participants with a mean age of 65.25 years. Most fractures were subcapital, and the majority of participants did not experience complications after surgery. The average length of the pre-operative hospital stay was 2.35 days, and the post-operative hospital stay was 6.75 days. Functional outcomes, evaluated using the Harris Hip Scoring System, showed varying degrees, with 70% of participants experiencing good outcomes.

CONCLUSION

The management of intracapsular femoral neck fractures in the elderly with cemented bipolar prostheses demonstrated favorable outcomes, including low morbidity, simple operative procedures, and satisfactory early functional results. The study supports the recommendation of cemented bipolar prostheses for femoral neck fractures in individuals over 60, emphasizing their superiority over bipolar hemiarthroplasty. The results contribute valuable insights for treatment decisions in hip fractures, especially considering evolving reimbursement mechanisms and merit-based incentive payments.

Systematic Review and Meta-Analysis of Studies Comparing the Rate of Post-operative Periprosthetic Fracture Following Hip Arthroplasty With a Polished Taper Slip versus Composite Beam Stem

BACKGROUND

We compared the incidence of postoperative periprosthetic femoral fractures (POPFF) following hip arthroplasty with either a cemented polished taper slip (PTS) stem or a cemented composite beam (CB) stem in comparative studies.

METHODS

A systematic review of comparative studies, written in English and published in peer-reviewed journals since the year 2000, was conducted. Study quality was assessed using the Newcastle-Ottawa scale.The overall study qualities were good. There were 913,021 patients from 18 cohorts included in the meta-analysis. There were 294,540 patients who received a CB stem and 618,481 received a PTS stem. Cohorts were classified as high- or low-risk for POPFF based on patient risk factors. A metanalysis was performed using a random effects model, and the relative incidence with 95% confidence intervals (CIs) was reported.

RESULTS

The patients at low risk of POPFF had an incidence rate ratio of 3.14 (CI: 2.48, 3.98) for the PTS group versus the CB group. Whereas, the patients at high risk of POPFF had an incidence rate ratio of 9.87 (CI: 3.63, 26.80) for the PTS group versus the CB group.

CONCLUSIONS

The risk of POPFF is lower when hip arthroplasty was performed using a CB stem versus a PTS stem. This protective effect was greatest in patients who had a higher risk of POPFF. Surgeons should consider the effect of cemented stem choice on the risk of subsequent periprosthetic femur fracture, particularly in frail or elderly patients who are at a higher risk of postoperative periprosthetic femoral fracture.

Survival rates of anatomically shaped and tapered slip cemented femoral implants: an analysis of 76,281 femoral implants of the Dutch arthroplasty register (LROI)

INTRODUCTION

In cemented total hip arthroplasty (THA) various shapes and geometries of femoral implants are in use. Collarless, polished, and tapered (CPT) implants, and anatomically shaped (AS) implants are most commonly used. Due to their different design features, this might lead to different survival outcomes. In this register-based study, overall implant survival and short-term complications of CPT and AS cemented implants were evaluated.

METHODS

Data of the Dutch Arthroplasty Register (LROI) were used. Cemented femoral implants, which could be classified as CPT or AS were included in this study. Implants were excluded when no classification could be made or if implanted <100 times. Survival analyses were performed using Kaplan-Meier survival analysis and multivariable Cox-proportional hazard analysis.

RESULTS

76,281 cemented THAs were included. At a mean of 5.1 years follow-up (SD 3.1, range 0-12 years), the overall survival of the AS implants was higher compared with the CPT implants, with a survival, of 99.2% and 99.0% respectively (log-rank; p < 0.001). Multivariable regression analysis revealed a higher rate for revision because of loosening of the AS implants (HR 2; CI, 1.4-3.1). AS implants had a lower rate for periprosthetic fractures compared with the CPT implants (HR 0.13; CI, 0.07-0.23).

CONCLUSIONS

Both designs show excellent overall survival rates at short-term follow-up. There is a higher overall survival of AS implants when compared with CPT implants. Revision for implant loosening, however, was statistically significantly higher in AS implants when compared with the CPT implants.

Patient and technical contributors to periprosthetic fracture around the CPT stem

INTRODUCTION

The incidence of postoperative periprosthetic fracture has been reported to be higher in polished tapered femoral stems with the CPT stem possibly of greatest concern. We report on the patient and surgical factors in a consecutive cohort of 2892 CPT stems implanted as part of a total hip construct, either electively or for the treatment of a fractured neck of femur (NOF) over a 15-year period.

METHODS

The Bluespier departmental database was used to identify any patients who been treated for a Vancouver B periprosthetic fracture around a CPT stem from 2008 to 2021. Patient demographics, mechanism of injury and fracture type were recorded. X-rays were reviewed to identify technical issues that may have contributed to the fracture.

RESULTS

A total of 70 fractures were treated. For elective cases the fracture rate was 1.52% while for stems implanted for treatment of a neck of femur fracture (NOF) it was 2.86%. There was a male preponderance and almost all fractures were low energy. The majority (52.9%) were B1 fractures. Only 8 (11.4%) involved a truly loose construct (B2L). The presence of an undersized and varus stem increased the risk of fracture particularly in the NOF population.

DISCUSSION

The results in this series are consistent with the registry data regarding the rate of failure of the CPT stem related to periprosthetic fracture. The patient population is typical of those who sustain a proximal femoral fracture in terms of age although we report a male preponderance. The importance of surgical technique in the placement of a correctly sized and aligned stem, particularly in those patients undergoing hip replacement for a neck of femur fracture is highlighted.

Frank Stinchfield Award: Creation of a Patient-Specific Total Hip Arthroplasty Periprosthetic Fracture Risk Calculator

BACKGROUND

Many risk factors have been described for periprosthetic femur fracture (PPFFx) following total hip arthroplasty (THA), yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to develop a high-dimensional, patient-specific risk-stratification nomogram that allows dynamic risk modification based on operative decisions.

METHODS

We evaluated 16,696 primary nononcologic THAs performed between 1998 and 2018. During a mean 6-year follow-up, 558 patients (3.3%) sustained a PPFFx. Patients were characterized by individual natural language processing-assisted chart review on nonmodifiable factors (demographics, THA indication, and comorbidities), and modifiable operative decisions (femoral fixation [cemented/uncemented], surgical approach [direct anterior, lateral, and posterior], and implant type [collared/collarless]). Multivariable Cox regression models and nomograms were developed with PPFFx as a binary outcome at 90 days, 1 year, and 5 years, postoperatively.

RESULTS

Patient-specific PPFFx risk based on comorbid profile was wide-ranging from 0.4-18% at 90 days, 0.4%-20% at 1 year, and 0.5%-25% at 5 years. Among 18 evaluated patient factors, 7 were retained in multivariable analyses. The 4 significant nonmodifiable factors included the following: women (hazard ratio (HR) = 1.6), older age (HR = 1.2 per 10 years), diagnosis of osteoporosis or use of osteoporosis medications (HR = 1.7), and indication for surgery other than osteoarthritis (HR = 2.2 for fracture, HR = 1.8 for inflammatory arthritis, HR = 1.7 for osteonecrosis). The 3 modifiable surgical factors were included as follows: uncemented femoral fixation (HR = 2.5), collarless femoral implants (HR = 1.3), and surgical approach other than direct anterior (lateral HR = 2.9, posterior HR = 1.9).

CONCLUSION

This patient-specific PPFFx risk calculator demonstrated a wide-ranging risk based on comorbid profile and enables surgeons to quantify risk mitigation based on operative decisions.

LEVEL OF EVIDENCE

Level III, Prognostic.

Collarless Polished Tapered Stems of Identical Shape Provide Differing Outcomes for Stainless Steel and Cobalt Chrome: A Biomechanical Study

Cemented polished tapered femoral stems (PTS) made of cobalt-chrome alloy (CoCr) are a known risk factor for periprosthetic fracture (PPF). The mechanical differences between CoCr-PTS and stainless-steel (SUS) PTS were investigated. CoCr stems having the same shape and surface roughness as the SUS Exeter^® stem were manufactured and dynamic loading tests were performed on three each. Stem subsidence and the compressive force at the bone-cement interface were recorded. Tantalum balls were injected into the cement, and their movement was tracked to indicate cement movement. Stem motions in the cement were greater for the CoCr stems than for the SUS stems. In addition, although we found a significant positive correlation between stem subsidence and compressive force in all stems, CoCr stems generated a compressive force over three times higher than SUS stems at the bone-cement interface with the same stem subsidence (p < 0.01). The final stem subsidence amount and final force were greater in the CoCr group (p < 0.01), and the ratio of tantalum ball vertical distance to stem subsidence was significantly smaller for CoCr than for SUS (p < 0.01). CoCr stems appear to move more easily in cement than SUS stems, which might contribute to the increased occurrence of PPF with the use of CoCr-PTS.

A multicentre comparative analysis of fixation versus revision surgery for periprosthetic femoral fractures following total hip arthroplasty with a cemented polished taper-slip femoral component

AIMS

The aim of this study was to compare open reduction and internal fixation (ORIF) with revision surgery for the surgical management of Unified Classification System (UCS) type B periprosthetic femoral fractures around cemented polished taper-slip femoral components following primary total hip arthroplasty (THA).

METHODS

Data were collected for patients admitted to five UK centres. The primary outcome measure was the two-year reoperation rate. Secondary outcomes were time to surgery, transfusion requirements, critical care requirements, length of stay, two-year local complication rates, six-month systemic complication rates, and mortality rates. Comparisons were made by the form of treatment (ORIF vs revision) and UCS type (B1 vs B2/B3). Kaplan-Meier survival analysis was performed with two-year reoperation for any reason as the endpoint.

RESULTS

A total of 317 periprosthetic fractures (in 317 patients) with a median follow-up of 3.6 years (interquartile range (IQR) 2.0 to 5.4) were included. The fractures were type B1 in 133 (42.0%), B2 in 170 (53.6%), and B3 in 14 patients (4.4%). ORIF was performed in 167 (52.7%) and revision in 150 patients (47.3%). The two-year reoperation rate (15.3% vs 7.2%; p = 0.021), time to surgery (4.0 days (IQR 2.0 to 7.0) vs 2.0 days (IQR 1.0 to 4.0); p < 0.001), transfusion requirements (55 patients (36.7%) vs 42 patients (25.1%); p = 0.026), critical care requirements (36 patients (24.0%) vs seven patients (4.2%); p < 0.001) and two-year local complication rates (26.7% vs 9.0%; p < 0.001) were significantly higher in the revision group. The two-year rate of survival was significantly higher for ORIF (91.9% (standard error (SE) 0.023%) vs 83.9% (SE 0.031%); p = 0.032) compared with revision. For B1 fractures, the two-year reoperation rate was significantly higher for revision compared with ORIF (29.4% vs 6.0%; p = 0.002) but this was similar for B2 and B3 fractures (9.8% vs 13.5%; p = 0.341). The most common indication for reoperation after revision was dislocation (12 patients; 8.0%).

CONCLUSION

Revision surgery has higher reoperation rates, longer surgical waiting times, higher transfusion requirements, and higher critical care requirements than ORIF in the management of periprosthetic fractures around polished taper-slip femoral components after THA. ORIF is a safe option providing anatomical reconstruction is achievable.Cite this article: Bone Joint J 2023;105-B(2):124-134.

Post-operative peri-prosthetic fracture rates following the use of cemented polished taper-slip stems for primary total hip arthroplasty: a systematic review

INTRODUCTION

Peri-prosthetic fractures (PPFs) are a serious complication of total hip arthroplasty (THA) associated with significant morbidity, mortality and re-operation similar to the rates seen following femoral neck fractures. When exploring the PPF rates around cemented stems, many studies combine the results of composite beam and taper-slip stems despite their different philosophies. This review looks specifically at PPFs with the use of cemented stems of the taper-slip philosophy to evaluate the demographics, PPF rate and fracture patterns in this patient cohort.

MATERIALS AND METHODS

A systematic search of Embase, Medline and CINAHL databases was performed to seek studies involving the use of cemented, polished, taper-slip stems, reporting on a rate of post-operative PPF and not involving patient cohorts that were exclusively hip fracture or revision arthroplasty.

RESULTS

27 studies reported on 505 PPFs with an average time from primary operation to PPF of 71.2 months (2-301 months). The average age of patients who sustained PPFs was 70.6 years (53.5-82 years) and the majority were female (64.2%). The Vancouver B2 fracture type was most common (39.5%). Open reduction and internal fixation represented the management of choice in 61.2% of PPFs. There was a re-operation rate of 11.4%.

CONCLUSION

This review suggests an association with being older and female, and a greater risk of PPFs secondary to low energy falls in cemented polished taper-slip stems.

Periprosthetic femoral fractures around the original cemented polished triple-tapered C-stem femoral implant: a consecutive series of 500 primary total hip arthroplasties with an average follow-up of 15 years

INTRODUCTION

The true incidence of periprosthetic femoral fracture (PFF) around cemented polished taper-slip implants remains largely unknown. Registries usually only capture PFFs that result in revision, missing those managed non-operatively or treated by open reduction and internal fixation (ORIF). This study reports the long-term rate of PFF with the original triple-tapered C-stem femoral implant.

MATERIALS AND METHODS

A prospective review of a consecutive series of 500 primary total hip arthroplasties (THAs) performed at a single centre between March 2000 and December 2005, with average follow-up of 15 years (12-19 years).

RESULTS

There were 500 consecutive THAs in 455 patients. Seven PFFs (1.4%) occurred in seven patients at an average of 7.9 years (range 2-11.5) from the primary arthroplasty. Five PFFs were managed by ORIF, one Vancouver B3 fracture was revised for a loose implant and one patient was treated non-operatively. Average age at primary operation was 74 years (67-87) and BMI averaged 27.3 (22-31). There was no typical fracture pattern and no statistically significant associations with patient demographics (age, gender, BMI, diagnosis) or prosthetic details (size, offset, alignment, cement mantle, subsidence). Survivorship to the occurrence of PFF was 99% (97.3-99.6%) at 10 years and 97.8% (95.5-99.0%) at 15.

CONCLUSION

A PFF rate of 1.4% at an average follow-up of 15 years represents the true incidence of PFF with the use of the original triple-tapered C-Stem femoral implant, similar to that of published Exeter series (1.85%) but lower than the CPT (3.3%).

[Effectiveness of shape memory alloy embracing device in treatment of Vancouver B2 periprosthetic femoral fracture]

OBJECTIVE

To analyze the effectiveness of shape memory alloy embracing device in the treatment of Vancouver B2 periprosthetic femoral fracture after primary hip arthroplasty.

METHODS

The clinical data of 30 patients (30 hips) with Vancouver B2 periprosthetic femoral fracture after primary hip arthroplasty between January 2019 and January 2021 were analyzed retrospectively. Among them, 15 cases were treated with shape memory alloy embracing device for fracture fixation (group A) and 15 cases with titanium cable cerclage (group B). There was no significant difference in general data such as gender, age, body mass index, the cause of primary arthroplasty and surgical method, prosthesis type, the cause and side of femoral fracture, the time from injury to operation, and comorbidities between the two groups ( P>0.05). The operation time, intraoperative blood loss, and hospital stay of the two groups were recorded. The fracture healing was examined by X-ray film, and the hip joint function was evaluated by Harris score.

RESULTS

The operations in both groups were completed successfully, and the incisions healed by first intention after operation with no vascular or nerve injury. The operation time and hospital stay in group A were significantly shorter than those in group B ( P<0.05), but there was no significant difference in intraoperative blood loss between group A and group B ( t=-0.518， P=0.609). Patients were followed up 12-20 months (mean, 16.3 months) in group A and 12-22 months (mean, 16.7 months) in group B. X-ray film showed that all fractures healed, the healing time was (14.73±2.05) weeks in group A and (17.27±2.60) weeks in group B, and there was a significant difference between the two groups ( t=-2.960， P=0.006). During follow-up, there was no complication such as prosthesis loosening, periprosthetic infection, joint stiffness, or internal fixator loosening. The Harris score of group A was significantly better than that of group B at 3, 6, and 12 months after operation ( P<0.05).

CONCLUSION

Compared with titanium cable cerclage, using shape memory alloy embracing device to fix Vancouver B2 periprosthetic femoral fracture can accelerate fracture healing, shorten operation time, and reduce intraoperative blood loss. Patients can perform functional exercise earlier and restore joint function better.

Periprosthetic Fracture around a Cemented Stem in Total Hip Arthroplasty

The increase in the number of primary total hip arthroplasties that will be performed over the next several decades will lead to an increase in the incidence of periprosthetic fractures around the femoral stem. A search of targeted articles was conducted using on-line databases of PubMed (National Library of Medicine) and articles were obtained from January 2008 to November 2021. Reliable prediction of treatment can be achieved using the Vancouver classification; internal fixation is indicated in fractures involving a stable implant and revision arthroplasty is indicated in those with unstable prostheses. To the best of our knowledge, relatively fewer studies regarding periprosthetic proximal femur fractures of cemented stems have been reported. The focus of this review is on the risk factors and strategies for treatment of these fractures for periprosthetic femoral fractures around a cemented hip arthroplasty.

The Effect of Femoral Fixation on Revision and Mortality Following Elective Total Hip Arthroplasty in Patients Over the Age of 65 years. An Analysis of the American Joint Replacement Registry

BACKGROUND

With the overwhelming use of cementless femoral fixation for primary total hip arthroplasty in the United States, the associations of stem fixation on the risk of revision and mortality are poorly understood. We evaluated the relationship between femoral fixation and risk of revision and mortality in patients included in the American Joint Replacement Registry.

METHODS

Elective, primary, unilateral total hip arthroplasties in the American Joint Replacement Registry, in patients over the age of 65 years were considered. In total, 9,612 patients with a cemented stem were exact matched 1:1 with patients who received a cementless stem based on age, gender, and the Charlson Comorbidity Index. Outcomes compared between the groups included need and reason for revision at 90 days and 1 year; in-hospital, 90-day, and 1-year mortality; and mortality after early revision. Covariates were used in linear regression analyses.

RESULTS

Cemented fixation was associated with a 37% reduction in the risk of 90-day revision, and a reduction in the risk of revision for periprosthetic fracture of 87% at 90 days and 81% at 1 year. Cemented fixation was associated with increased 90-day and 1-year mortality (odds ratio [OR] 3.15, confidence interval [CI] 2.24-4.43 and OR 2.36, CI 1.86-3.01, respectively). Patients who underwent subsequent revision surgery within the first year exhibited the highest mortality risk (OR 3.23, CI 1.05-9.97).

CONCLUSION

In this representative sample of the United States, 90-day revision for any reason and for periprosthetic fracture was significantly reduced in patients with a cemented stem. This benefit must be weighed against the association with increased mortality and with the high risk of mortality associated with early revision, which was more prevalent with cementless fixation.

The influence of calcar collar and surface finish in the cemented femoral component on the incidence of postoperative periprosthetic femoral fracture at a minimum of five years after primary total hip arthroplasty

INTRODUCTION

Cemented femoral component design including its mechanical behavior in total hip arthroplasty (THA) has influenced the occurrence of postoperative periprosthetic femoral fracture (PPFF). The main aim of this study was to investigate the influence of the calcar collar and surface finish in the cemented femoral component on the risk of PPFF.

MATERIALS AND METHODS

This retrospective review was undertaken of 1082 primary THAs in 912 patients using cemented femoral components followed for a minimum of five years (mean, 9.4 years; range, 5-24 years). The incidence of PPFF, patients' demographics and surgical details were evaluated. Kaplan-Meier survivorship analysis was performed for four different outcomes: any PPFF, revision of the femoral component for PPFF, aseptic loosening, and for any reason.

RESULTS

The overall incidence of PPFFs was 1.0% (n = 11): 1.4% (n = 10) in the collarless polished (CLP) group, none in the collared polished (CP) group and 0.6% (n = 1) in the collared non-polished (CNP) group (p > 0.05). Kaplan-Meier survival analysis for the femoral component at 12 years with PPFF as the end point was 97.4% (95% confidence interval [CI], 94.9 to 99.8) in the collarless group and 99.7% (95% CI, 99.1 to 100) in the collared group (p = 0.048). With revision of the femoral component for aseptic loosening as the end point, survivorship was 100.0% in the CLP and CP groups, and 98.1% (95% CI, 95.9 to 100) in the CNP group (CLP vs CP, p > 0.999; CLP vs CNP, p = 0.001; CP vs CNP, p = 0.112).

CONCLUSION

This study demonstrated that the calcar collar in the cemented femoral component could play an important role to reduce the incidence of PPFF. The surface finish in the cemented femoral components influenced the incidence of femoral component revision for aseptic loosening over 5-12 years. Surgeons should consider not only the geometry and the mechanical function of the femoral components based on different design philosophies, but also potential complications associated with different designs that may require revision arthroplasty.

Comparison of periprosthetic femoral fracture torque and strain pattern of three types of femoral components in experimental model

AIMS

Periprosthetic hip fractures (PPFs) after total hip arthroplasty are difficult to treat. Therefore, it is important to identify modifiable risk factors such as stem selection to reduce the occurrence of PPFs. This study aimed to clarify differences in fracture torque, surface strain, and fracture type analysis between three different types of cemented stems.

METHODS

We conducted biomechanical testing of bone analogues using six cemented stems of three different types: collarless polished tapered (CPT) stem, Versys Advocate (Versys) stem, and Charnley-Marcel-Kerboull (CMK) stem. Experienced surgeons implanted each of these types of stems into six bone analogues, and the analogues were compressed and internally rotated until failure. Torque to fracture and fracture type were recorded. We also measured surface strain distribution using triaxial rosettes.

RESULTS

There was a significant difference in fracture torque between the three stem types (p = 0.036). Particularly, the median fracture torque for the CPT stem was significantly lower than that for the CMK stem (CPT vs CMK: 164.5 Nm vs 200.5 Nm; p = 0.046). The strain values for the CPT stem were higher than those for the other two stems at the most proximal site. The fracture pattern of the CPT and Versys stems was Vancouver type B, whereas that of the CMK stem was type C.

CONCLUSION

Our study suggested that the cobalt-chromium alloy material, polished surface finish, acute-square proximal form, and the absence of a collar may be associated with lower fracture torque, which may be related to PPF. Cite this article: Bone Joint Res 2022;11(5):270-277.

Prevention of early complications following total hip replacement

Total hip arthroplasty (THA) has been quoted as "the operation of the century", owing to its efficacy and the substantial improvements evidenced with respect to functional patient outcomes and quality of life. However, early postoperative complications are often inevitable, hence it is imperative to take every step to prevent them and minimise morbidity and mortality. This manuscript focuses on the most common early complications following THA, namely venous thromboembolism (VTE), prosthetic joint infection, periprosthetic fracture, instability, and leg length inequality. It aims to outline effective risk stratification strategies and prevention measures that could apply to the wider Orthopaedic community.

Periprosthetic Femoral Fracture Is a Leading Cause of Early Revision With Taper-Slip Stems in Primary Total Hip Arthroplasty: An Analysis of 2765 Total Hip Arthroplasties From a High-Volume Hospital

BACKGROUND

In 2016, the CPT stem replaced the Exeter stem as the main cemented stem at our institution. We assessed the prevalence of revision for periprosthetic femoral fracture (PFF) in patients operated on with either CPT or Exeter stem and compared the risk for revision between these stems.

METHODS

Primary total hip arthroplasties either performed in 2012-2015 with Exeter stem (n = 1443) or in 2017-2018 with CPT stem (n = 1322) were included. The prevalence of revision for PFF was compared. The Kaplan-Meier estimated survivorships were calculated for the 2 stem designs. The risk for revision was analyzed using the Cox proportional hazard regression model.

RESULTS

At 2 years, PFF was the most common reason for revision in the study population (1.3% prevalence, comprising 35% of all revisions). Moreover, 1.6% (95% confidence interval [CI] 1.0-2.4) of the CPT and 1.0% (95% CI 0.6-1.6) of the Exeter stems had been revised due to PFF. The 3-year Kaplan-Meier probability estimates for all-cause revision were 4.8% for the CPT (95% CI 3.6-6.0) and 3.3% for the Exeter stem (95% CI 2.3-4.3). The hazard ratio for revision due to any reason was 1.1 (95% CI 0.3-3.8) during the first 2 weeks, and 1.8 (95% CI 1.2-2.7, P = .006) from 2 weeks onwards for the CPT compared with the Exeter stem.

CONCLUSION

The considerable number of PFF revisions with taper-slip stems, especially with CPT stems, is a matter of concern. Alternative cemented stems should be considered in patients at high risk for PFF.

Hip prosthetic loosening: A very personal review

Hip prosthetic loosening is often difficult to detect at an early stage, and there has been uncertainty for a long time as to when the loosening occurs and thus to the basic causes. By comparing different diagnostic methods, we found that loosening is best defined as prosthetic migration and measured by radiostereometric analysis. Convincing evidence indicates that poor interlock, poor bone quality, and resorption of a necrotic bone bed may initiate loosening during or shortly after surgery; this forms the basis of the theory of early loosening. Biomechanical factors do affect the subsequent progression of loosening, which may increase subclinically during a long period of time. Eventually, the loosening may be detected on standard radiographs and may be interpreted as late loosening but should to be interpreted as late detection of loosening. The theory of early loosening explains the rapid early migration, the development of periprosthetic osteolysis and granulomas, the causality between wear and loosening, and largely the epidemiology of clinical failure of hip prostheses. Aspects discussed are definition of loosening, the pattern of early migration, the choice of migration threshold, the current understanding of loosening, a less exothermic bone cement, cemented taper-slip stems, a new exciting computed tomography-based technique for simpler implant migration studies, and research suggestions.

Acute femoral fracture does not compromise the outcome of total hip arthroplasty : 5 year results from a single center cohort study in 2,782 patients

National arthroplasty registries reveal a higher risk of revision for periprosthetic fracture and dislocation after total hip arthroplasty (THA) in patients with a femoral neck fracture compared to those with osteoarthritis (OA). Since these registries may con- tain confounding factors, we conducted a single center cohort study comparing survival and reason for failure between THA for an acute femoral neck fracture and OA using the same hip prosthesis after a minimum follow-up of 2 years. We retrospectively analyzed 2782 patients who had undergone THA with an Accolade TMZF stem and a Trident cup between March 2009 and September 2014. Primary diagnosis before THA was osteoarthritis (OA group : n=2610) or acute femoral fracture (Fracture group : n=172). Patients in both groups were operated on by the same hip surgeons. Effect of diagnosis on THA survival was analyzed using Cox-regression analysis. Chi-square tests were used to illustrate the different reasons for revision between the groups. Mean follow-up was 4.6 years (2-7.6). A total of 100 revisions were performed. The revision risk was comparable between the OA and Fracture group (HR=1.04, 95% CI :0.46-2.39). No differences were found between the OA and Fracture group with respect to the occurrence of periprosthetic fractures (0.8% vs. 0.6%, p=0.71) and revisions for dislocation (0.6% vs. 1.2%, p=0.38). We found no difference in outcome or reason for revision between THA for OA or femoral neck frac- ture. Using an implant with a proven ODEP rating and having experienced hip surgeons carry out the procedures may be more important than the primary diagnosis.

Reliability and validity of the Unified Classification System for postoperative periprosthetic femoral fractures around cemented polished taper-slip stems

AIMS

This aim of this study was to assess the reliability and validity of the Unified Classification System (UCS) for postoperative periprosthetic femoral fractures (PFFs) around cemented polished taper-slip (PTS) stems.

METHODS

Radiographs of 71 patients with a PFF admitted consecutively at two centres between 25 February 2012 and 19 May 2020 were collated by an independent investigator. Six observers (three hip consultants and three trainees) were familiarized with the UCS. Each PFF was classified on two separate occasions, with a mean time between assessments of 22.7 days (16 to 29). Interobserver reliability for more than two observers was assessed using percentage agreement and Fleiss' kappa statistic. Intraobserver reliability between two observers was calculated with Cohen kappa statistic. Validity was tested on surgically managed UCS type B PFFs where stem stability was documented in operation notes (n = 50). Validity was assessed using percentage agreement and Cohen kappa statistic between radiological assessment and intraoperative findings. Kappa statistics were interpreted using Landis and Koch criteria. All six observers were blinded to operation notes and postoperative radiographs.

RESULTS

Interobserver reliability percentage agreement was 58.5% and the overall kappa value was 0.442 (moderate agreement). Lowest kappa values were seen for type B fractures (0.095 to 0.360). The mean intraobserver reliability kappa value was 0.672 (0.447 to 0.867), indicating substantial agreement. Validity percentage agreement was 65.7% and the mean kappa value was 0.300 (0.160 to 0.4400) indicating only fair agreement.

CONCLUSION

This study demonstrates that the UCS is unsatisfactory for the classification of PFFs around PTS stems, and that it has considerably lower reliability and validity than previously described for other stem types. Radiological PTS stem loosening in the presence of PFF is poorly defined and formal intraoperative testing of stem stability is recommended. Cite this article: Bone Joint J 2021;103-B(8):1339-1344.

Relationship between the Surface Roughness of Material and Bone Cement: An Increased "Polished" Stem May Result in the Excessive Taper-Slip

Although some reports suggest that taper-slip cemented stems may be associated with a higher periprosthetic femoral fractures rate than composite-beam cemented stems, few studies have focused on the biomaterial effect of the polished material on the stem–cement interface. The purpose of this study was to investigate the relationship between surface roughness of materials and bone cement. Four types of metal discs—cobalt-chromium-molybdenum alloy (CoCr), stainless steel alloy 316 (SUS), and two titanium alloys (Ti-6Al-4V and Ti-15Mo-5Zr-3Al)—were prepared. Five discs of each material were produced with varying degrees of surface roughness. In order to evaluate surface wettability, the contact angle was measured using the sessile drop method. A pin was made using two bone cements and the frictional coefficient was assessed with a pin-on-disc test. The contact angle of each metal increased with decreasing surface roughness and the surface wettability of metal decreased with higher degrees of polishing. With a surface roughness of Ra = 0.06 μm and moderate viscosity bone cement, the frictional coefficient was significantly lower in CoCr than in SUS (p = 0.0073). In CoCr, the low adhesion effect with low frictional coefficient may result in excessive taper-slip, especially with the use of moderate viscosity bone cement.

Risk factors influencing fracture characteristics in postoperative periprosthetic femoral fractures around cemented stems in total hip arthroplasty : a multicentre observational cohort study on 584 fractures

Aims

This study evaluates risk factors influencing fracture characteristics for postoperative periprosthetic femoral fractures (PFFs) around cemented stems in total hip arthroplasty.

Methods

Data were collected for PFF patients admitted to eight UK centres between 25 May 2006 and 1 March 2020. Radiographs were assessed for Unified Classification System (UCS) grade and AO/OTA type. Statistical comparisons investigated relationships by age, gender, and stem fixation philosophy (polished taper-slip (PTS) vs composite beam (CB)). The effect of multiple variables was estimated using multinomial logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Surgical treatment (revision vs fixation) was compared by UCS grade and AO/OTA type.

Results

A total of 584 cases were included. Median age was 79.1 years (interquartile range 72.0 to 86.0), 312 (53.6%) patients were female, and 495 (85.1%) stems were PTS. The commonest UCS grade was type B1 (278, 47.6%). The most common AO/OTA type was spiral (352, 60.3%). Metaphyseal split fractures occurred only with PTS stems with an incidence of 10.1%. Male sex was associated with a five-fold reduction in odds of a type C fracture (OR 0.22 (95% CI 0.12 to 0.41); p < 0.001) compared to a type B fracture. CB stems were associated with significantly increased odds of transverse fracture (OR 9.51 (95% CI 3.72 to 24.34); p < 0.001) and wedge fracture (OR 3.72 (95% CI 1.16 to 11.95); p = 0.027) compared to PTS stems. Both UCS grade and AO/OTA type differed significantly (p < 0.001 and p = 0.001, respectively) between the revision and fixation groups but a similar proportion of B1 fractures underwent revision compared to fixation (45.3% vs 50.6%).

Conclusion

The commonest fracture types are B1 and spiral fractures. PTS stems are exclusively associated with metaphyseal split fractures, but their incidence is low. Males have lower odds of UCS grade C fractures compared to females. CB stems have higher odds of bending type fractures (transverse and wedge) compared to PTS stems. There is considerable variation in practice when treating B1 fractures around cemented stems.

Cite this article: Bone Jt Open 2021;2(7):466–475.

The influence of femoral component design on postoperative periprosthetic femoral fracture after uncemented direct anterior total hip arthroplasty in the elderly

Introduction

Aging populations and expanding indications will greatly increase the volume of total hip arthroplasty (THA) in all age groups, including patients over 70 years old. Minimally invasive, uncemented direct anterior THA offers potential advantages for treating elderly patients. However, literature indicates higher risks of postoperative periprosthetic femur fractures (PPFFs) with both direct anterior THA and uncemented femoral stems. This retrospective study investigates the influence of femoral stem design on PPFF incidence in uncemented direct anterior THA among patients older than 70 years.

Methods

557 primary THAs in patients aged 70 or over were reviewed for PPFFs from a consecutive series of 2011 patients undergoing direct anterior THA from a fellowship-trained adult reconstruction surgeon from 2015 to 2020. Exclusion criteria included age (<70) and posterior approach. For the first cohort of 361 patients (79 of which passed exclusion criteria) the surgeon used a single-tapered, proximally porous coated, collarless titanium stem. For the next 1650, (478 of which passed exclusion), the surgeon used a dual-tapered, collared, hydroxyapatite-coated titanium stem. Included patients were carefully monitored until March 2021 for PPFFs. A Fisher's exact test was used to compare the incidence PPFFs between the 2 implant designs.

Results

2 of 79 (2.5%) patients had atraumatic PPFFs at an average of 19.5 days post-operatively in the first cohort. Both experienced a Vancouver type B2 periprosthetic fracture and required femoral revision. No patients (0/478, 0%) in the second group sustained a PPFF. (P = 0.0199).

Conclusion

In this comparison, the dual-taper, hydroxyapatite-coated implant had a significantly lower PPFF rate among elderly patients than a single-taper, proximally porous stem without a collar.

Cemented hemiarthroplasty for femoral neck fracture patients: collarless, polished tapered stem (CPT) versus anatomic matte stem (Lubinus SP2)

BACKGROUND

Cemented hemiarthroplasty is a well-documented treatment for patients with femoral neck fractures (FNFs). However, there are not many cohort studies comparing different types of hemiarthroplasty (HA).

OBJECTIVE

To compare CPT and Lubinus SP2 HA for FNF patients concerning complications and radiological measurements.

METHODS

From January 1, 2013, CPT was introduced instead of Lubinus SP2 as the new cemented HA due to a regional procurement. Data were retrieved 3 years prior and after the introduction. All patient health records were retrospectively reviewed for types of implant, American Society of Anesthesiologists (ASA) score and duration of admission. All X-ray images were analyzed for radiological measurements concerning offset, stem angulation and cement filling. Mortality and major complications within 1 year were retrieved from patient health records as well as the Danish National Patient Registry. Major complications were defined as dislocations, periprosthetic fractures and revisions.

RESULTS

584 cemented HA were included, 300 CPT and 284 with Lubinus SP2. The mean age (SD) was 82 (8.2) years, and there was no baseline difference between the groups concerning age, sex, ASA score and mortality. There were 8.7% major complications for CPT and 9.2% for Lubinus SP2 (p = 0.836). There were, however, seven periprosthetic fractures in the CPT group and one in the Lubinus SP2 group (p = 0.04). In contrast, there were 20 dislocations in the Lubinus SP2 group and 10 in the CPT group (p = 0.042). There was no statistical difference between the stem angulation and periprosthetic fractures (p = 0.824) or major complications (p = 0.602). The Lubinus SP2 had a mean plus 2.7 mm offset postoperatively (p = 0.001), while the CPT had plus 10.6 mm (p < 0.000). The mean (SD) angle of the stems was 1.39 (1.75) degrees for Lubinus SP2 and 2.46 (1.99) for CPT. There was no difference in cementation (p = 0.308).

CONCLUSION

There was no overall statistical difference between the CPT and Lubinus SP2 stem regarding major complications. However, the CPT had a higher prevalence of periprosthetic fractures, while the Lubinus SP2 had a higher dislocation prevalence. The CPT stem had overcorrection of offset and a higher degree of varus positioning.

Mind the gap! The Lucent Line Sign: A Pathognomonic Radiographic Finding in Periprosthetic Hip Fractures Around Cemented Polished Tapered Femoral Stems

Background:

Diagnosing minimally displaced femoral PPFs using plain-film radiographs can be challenging. As a result, fractures can be missed.

Case Report:

We present four cases of minimally displaced PPFs around cemented polished tapered stems. In each case, radiographs demonstrate no clear cortical breach, but the presence of a fracture is highlighted by a pathognomic lucent line between the cement mantle and the prosthesis: The Lucent Line Sign.

Conclusion:

Paying attention to the Lucent Line Sign can be pivotal in the diagnosis of minimally displaced PPFs around cemented polished tapered stems.

Intraoperative Periprosthetic Fractures in Total Hip Arthroplasty in Patients With Sickle Cell Disease at King Fahad Hospital Hofuf: A Cross-Sectional Study

Background  Patients with avascular necrosis related to sickle cell disease (SCD) can be severely disabled by the severe degenerative changes of their hip. Total hip arthroplasty (THA) remains the only surgical option for some of these patients. Total hip arthroplasty can be a challenging procedure, and SCD patients demonstrate high percentages of medical, intraoperative, and postoperative complications and implant failure. Furthermore, the need for THA following avascular necrosis in the Eastern Province of Saudi Arabia is high, and the subsequent risk of periprosthetic fracture is prevalent. Therefore, it is crucial to conduct such a study. Aim of the study This cross-sectional retrospective study aimed to assess the prevalence and associated risk factors for periprosthetic fractures during total hip arthroplasty in sickle cell disease patients at King Fahad Hospital Hofuf, Saudi Arabia. Methods We collected the data of all SCD patients who had undergone THA during the study period, January 2015 to September 2020. Forty-nine SCD patients who had undergone THA during the study period were included. Patients who had undergone hip hemiarthroplasty, postoperative fractures, or had an indication of THA other than avascular necrosis were excluded. Surgeon factors, assistant factors, and surgical technique were also excluded. We then analyzed the data according to gender, age, BMI, American Society of Anesthesiologists classification, implant fixation type, avascular necrosis stage, proximal femoral morphology, Vancouver classification type, sickle cell type, preoperative hemoglobin (Hb) level, and the risk of periprosthetic fractures. Descriptive statistics were presented using frequency and percentages for categorical variables, and continuous variables were summarized using means ± standard deviations. Independent t-tests and chi-square tests were used to test for associations between categorical variables. At 0.05, the significance level was set. Results  Of the patients, 32.7% were male and 67.3% were female. 32.7% of the patients had advanced degenerative changes due to avascular necrosis. Among the patients, 20.4% had an intraoperative periprosthetic femoral fracture, 90% had a Vancouver classification class A, and 10% had a Vancouver classification class B1. According to Dorr classification, 75.5% were classified as Dorr A and 24.5% as Dorr B. Of the patients, 48 had an uncemented implant, and only 1 had cemented. The mean perioperative Hb was 9.02 + 2.02, with a minimum of 6 and a maximum of 14. No significant associations were found between the incidence of intraoperative femoral fracture and the demographic variables and the operative profile characteristics. However, a significantly higher rate of fracture was observed in patients operated on the right side compared to patients operated on the left side. Conclusion The prevalence of periprosthetic intraoperative fracture among SCD patients at King Fahad Hospital Hofuf was 20.4% during the study period. Even with adequate perioperative management, orthopedic surgeons must be prepared to deal with high rates of intraoperative fracture. No significant association was found between the incidence of intraoperative femoral fracture in SCD patients and the demographic variables and the operative profiles. However, a significantly higher rate of fracture was observed in patients operated on the right side compared to patients operated on the left side.

Postoperative periprosthetic femoral fracture around total hip replacements: current concepts and clinical outcomes

The rising incidence of postoperative periprosthetic femoral fracture (PFF) presents a significant clinical and economic burden.

A detailed understanding of risk factors is required in order to guide preventative strategies.

Different femoral stems have unique characteristics and management strategies must be tailored appropriately.

Consensus regarding treatment of PFFs around well-fixed stems is lacking, but revision surgery may provide more predictable outcomes for unstable fracture patterns and fractures around polished taper-slip stems.

Future research should focus on implant-related risk factors, treatment of concurrent metabolic bone disease and the use of large endoprostheses.

Cite this article: EFORT Open Rev 2020;5:558-567. DOI: 10.1302/2058-5241.5.200003

A Calcar Collar Is Protective Against Early Torsional/Spiral Periprosthetic Femoral Fracture: A Paired Cadaveric Biomechanical Analysis

BACKGROUND

Periprosthetic fracture is a leading reason for readmission following total hip arthroplasty. Most of these fractures occur during the early postoperative period before bone ingrowth. Before ingrowth occurs, the femoral component can rotate relative to the femoral canal, causing a spiral fracture pattern. We sought to evaluate, in a paired cadaver model, whether the torsional load to fracture was higher in collared stems. The hypothesis was that collared stems have greater load to fracture under axial and torsional loads compared with collarless stems.

METHODS

Twenty-two cadaveric femora (11 matched pairs) with a mean age of 77 ± 10.2 years (range, 54 to 90 years) were harvested. Following dissection, the femora were evaluated with use of a dual x-ray absorptiometry scanner and T scores were recorded. We utilized a common stem that is available with the same intraosseous geometry with and without a collar. For each pair, 1 femur was implanted with a collared stem and the contralateral femur was implanted with a collarless stem with use of a standard broaching technique. A compressive 68-kg load was applied to simulate body weight during ambulation. A rotational displacement was then applied until fracture occurred. Peak torque prior to fracture was measured with use of a torque meter load cell and data acquisition software.

RESULTS

The median torque to fracture was 65.4 Nm for collared stems and 43.1 Nm for uncollared stems (p = 0.0014, Wilcoxon signed-rank test). The median T score was -1.95 (range, -4.1 to -0.15). The median difference in torque to fracture was 29.18 Nm. As expected in each case, the mode of failure was a spiral fracture around the implant.

CONCLUSIONS

Collared stems seemed to offer a protective effect in torsional loading in this biomechanical model comparing matched femora.

CLINICAL RELEVANCE

These results may translate into a protective effect against early periprosthetic Vancouver B2 femoral fractures that occur before osseous integration has occurred.

Greater increase in femoral offset with use of collum femoris-preserving stem than Tri-Lock stem in primary total hip arthroplasty

OBJECTIVE

This study was performed to compare the clinical outcomes and performance of the collum femoris-preserving (CFP) stem (Waldemar Link GmbH & Co., Hamburg, Germany) and the Tri-Lock stem (DePuy Orthopaedics, Warsaw, IN, USA) in terms of femoral offset (FO) and leg length reconstruction.

METHODS

Clinical and radiographic data of patients who underwent total hip arthroplasty with either a CFP stem or Tri-Lock stem from January 2016 to March 2017 were compared (65 and 57 patients, respectively). The Harris hip score and Western Ontario and McMaster Universities Osteoarthritis Index were recorded. The FO, femoral vertical offset, and neck-shaft angle were measured at the last follow-up. The occurrence of dislocation and periprosthetic fracture during the follow-up period was recorded.

RESULTS

The CFP stem induced significantly more FO than did the Tri-Lock stem on the operated side than contralateral side (3.63 ± 4.28 vs. 0.83 ± 5.46 mm). Significantly fewer patients had a >5-mm decrease in FO on the unaffected side in the CFP stem group (n = 1) than Tri-Lock stem group (n = 10).

CONCLUSION

Both stems similarly improved hip function and reconstructed the leg length, but the CFP stem was superior to the Tri-Lock stem in reconstructing FO.

Current concepts and outcomes in cemented femoral stem design and cementation techniques: the argument for a new classification system

Cemented implant fixation design principles have evolved since the 1950s, and various femoral stem designs are currently in use to provide a stable construct between the implant-cement and cement-bone interfaces.Cemented stems have classically been classified into two broad categories: taper slip or force closed, and composite beams or shaped closed designs. While these simplifications are acceptable general categories, there are other important surgical details that need to be taken into consideration such as different broaching techniques, cementing techniques and mantle thickness.With the evolution of cemented implants, the introduction of newer implants which have hybrid properties, and the use of different broaching techniques, the classification of a very heterogenous group of implants into simple binary categories becomes increasingly difficult. A more comprehensive classification system would aid in comparison of results and better understanding of the implants' biomechanics.We review these differing stem designs, their respective cementing techniques and geometries. We then propose a simple four-part classification system and summarize the long-term outcomes and international registry data for each respective type of cemented prosthesis. Cite this article: EFORT Open Rev 2020;5:241-252. DOI: 10.1302/2058-5241.5.190034.

Periprosthetic proximal femoral fractures in cemented and uncemented stems according to Vancouver classification: observation of a new fracture pattern

BACKGROUND

Periprosthetic fractures are increasingly encountered in hip arthroplasty. The Vancouver classification system is widely used. Little knowledge exists regarding the association of the Vancouver classification with either cemented or uncemented stems. The aim was to analyse a series of fractures and determine associations.

METHODS

A series of consecutive patients over 8 years was identified including only post-operative fractures of primary hip arthroplasties. Baseline and radiographic characteristics were recorded including the type of stem fixation (cemented or uncemented) and Vancouver classification. Statistical analysis was performed to determine the association of the Vancouver classification between cemented and uncemented stems.

RESULTS

A total of 172 patients were identified (84 cemented stems, 88 uncemented stems). There were 30 Vancouver A fractures (12 cemented vs.18 uncemented, p > 0.05), 125 Vancouver B fractures (63 cemented vs. 62 uncemented, p > 0.05) and 17 Vancouver C fractures (9 cemented vs. 8 uncemented, p > 0.05). The Vancouver B2 fracture occurred most frequently (N = 95; 44 cemented vs. 51 uncemented, p > 0.05) and consists of four distinct fracture patterns: the previously described comminuted 'burst', clamshell and spiral patterns and the newly observed 'reverse' clamshell. The burst and spiral fracture patterns are significantly associated with cemented stems, and the clamshell pattern is significantly associated with uncemented stems.

CONCLUSIONS

Vancouver A, B and C fractures occur equally in cemented and uncemented stems. Awareness of four distinct Vancouver B2 fracture patterns, including the newly observed reverse clamshell, will aid surgeons in predicting stem instability.

Increased risk for postoperative periprosthetic fracture in hip fracture patients with the Exeter stem than the anatomic SP2 Lubinus stem

Background

The purpose of this study was to compare the cumulative incidence of postoperative periprosthetic fracture (PPF) in a cohort of femoral neck fracture (FNF) patients treated with two commonly used cemented stems: either a collarless, polished, tapered Exeter stem or the anatomic Lubinus SP2 stem.

Methods

In this retrospective multicenter cohort study of a consecutive series of patients, we included 2528 patients of age 60 years and above with an FNF who were treated with either hemiarthroplasty or total hip arthroplasty using either a polished tapered Exeter stem or an anatomic Lubinus SP2 stem. The incidence of PPF was assessed at a minimum of 2 years postoperatively.

Results

The incidence of PPF was assessed at a median follow-up of 47 months postoperatively. Thirty nine patients (1.5%) sustained a PPF at a median of 27 months (range 0–96 months) postoperatively. Two of the operatively treated fractures were Vancouver A (5%), 7 were Vancouver B1 (18%), 10 were Vancouver B2 (26%), 7 were Vancouver B3 (18%), and 13 were Vancouver C (32%). The cumulative incidence of PPF was 2.3% in the Exeter group compared with 0.7% in the SP2 group (p < 0.001). The HR was 5.4 (95% CI 2.4–12.5, p < 0.001), using the SP2 group as the denominator.

Conclusions

The Exeter stem was associated with a higher risk for PPF than the Lubinus SP2 stem. We suggest that the tapered Exeter stem should be used with caution in the treatment of FNF.

Trial registration

The study was registered at clinicaltrials.gov (identifier: NCT03326271).

Outcomes of Total Hip Arthroplasty in Patients with Osteonecrosis of the Femoral Head Following Surgical Treatment of Brain Tumors

Corticosteroids have been widely used in patients with brain tumors to reduce tumor-associated edema and neurological deficits. This study examined the outcomes of total hip arthroplasty (THA) in patients with osteonecrosis of the femoral head (ONFH) following brain tumor surgery. We identified 34 THAs performed in 26 patients with steroid-induced ONFH among 9254 patients undergoing surgical treatment for primary brain tumors. After propensity score matching with demographics, 68 THAs (52 patients) in ONFH unrelated to brain tumors were selected as the control group. At the time of THA, 54% of brain tumor patients had neurological sequelae and 46% had adrenal insufficiency. After THA, patients with brain tumor required longer hospital stay, reported a lower functional score, and showed a higher rate of heterotopic ossification compared to the control group. However, hip pain score improved significantly after THA in the brain tumor group, and did not differ from that of the control group (P-value = 0.168). Major complication rates were similar (2.9% and 1.5% for the brain tumor and control groups, respectively; P-value = 1.000), and implant survivorships were not different at 7 years (100% and 98.1% for the brain tumor and control groups, respectively; P-value = 0.455). Our findings suggest that THA can be safely performed to reduce hip pain in patients with steroid-induced ONFH after surgical treatment of primary brain tumors.

Reduced periprosthetic fracture rate when changing from a tapered polished stem to an anatomical stem for cemented hip arthroplasty: an observational prospective cohort study with a follow-up of 2 years

Background and purpose - Straight collarless polished tapered stems have been linked to an increased risk for periprosthetic femur fractures in comparison with anatomically shaped stems, especially in elderly patients. Therefore, we evaluated the effect of an orthopedic department's full transition from the use of a cemented collarless, polished, tapered stem to a cemented anatomic stem on the cumulative incidence of postoperative periprosthetic fracture (PPF). Patients and methods - This prospective single-center cohort study comprises a consecutive series of 1,077 patients who underwent a cemented hip arthroplasty using either a collarless polished tapered stem (PTS group, n = 543) or an anatomic stem (AS group, n = 534). We assessed the incidence of PPF 2 years postoperatively and used a Cox regression model adjusted for age, sex, ASA class, cognitive impairment, BMI, diagnosis, and surgical approach for outcome analysis. Results - Mean age at primary surgery was 82 years (49-102), 73% of the patients were female, and 75% underwent surgery for a femoral neck fracture. The PPF rate was lowered from 3.3% (n = 18) in the PTS group to 0.4% (n = 2) in the AS group. The overall complication rate was also lowered from 8.8% in the PTS group to 4.5% in the AS group. In the regression model only cognitive dysfunction (HR 3.8, 95% CI 1.4-10) and the type of stem (PTS vs AS, HR 0.1, CI 0.0-0.5) were correlated with outcome. Interpretation - For elderly patients with poor bone quality use of cemented anatomic stems leads to a substantial reduction in periprosthetic fracture rate without increasing other complications.

Effects of femoral bone defect morphology on initial polished tapered stem stability in massive defect model: a biomechanical study

Background

Good outcomes have been reported in revision total hip replacement with massive segmental defects using impaction bone grafting with circumferential metal meshes. However, the morphology of defects that require a mesh is poorly defined. The purpose of this study was to evaluate the effects of a variety of segmental defects on load transmission to the proximal femur under both axial and rotational loads.

Methods

Initial stability of the Exeter stem was investigated in a composite bone model using three medial bone defect morphologies: Long (length 5 cm × width 2 cm), Short (2.5 cm × 2 cm), Square (3.2 cm × 3.2 cm), Square with mesh (3.2 cm × 3.2 cm defect covered with metal mesh), and with no defect as control. Specimens (5 per group) were axially loaded and internally rotated up to 20° or to failure. Strain distributions of the femora were measured using a strain gauge.

Results

All Square group specimens failed while rotation was increasing. In the other four groups, failure was not observed in any specimens. Mean torsional stiffness in the Long (4.4 ± 0.3 Nm/deg.) and Square groups (4.3 ± 0.3 Nm/deg.) was significantly smaller than in the Control group (4.8 ± 0.3 Nm/deg.). In the medio-cranial region, the magnitude of the maximum principal strain in the Square group (1176.4 ± 100.9) was significantly the largest (Control, 373.2 ± 129.5, p < 0.001; Long, 883.7 ± 153.3, p = 0.027; Short, 434.5 ± 196.8, p < 0.001; Square with mesh, 256.9 ± 100.8, p < 0.001). Torsional stiffness, and both maximum and minimum principal strains in the Short group showed no difference compared to the Control group in any region.

Conclusions

Bone defect morphology greatly affected initial stem stability and load transmission. If defect morphology is not wide and the distal end is above the lower end of the lesser trochanter, it may be acceptable to fill the bone defect region with bone cement. However, this procedure is not acceptable for defects extending distally below the lower end of the lesser trochanter or defects 3 cm or more in width.

Perioperative Periprosthetic Femur Fractures are Strongly Correlated With Fixation Method: an Analysis From the American Joint Replacement Registry

BACKGROUND

Perioperative periprosthetic femur fractures (PPFx) after total hip arthroplasty (THA) remain a leading cause of early stem failure and revision and are associated with high rates of morbidity and mortality. American Joint Replacement Registry (AJRR) data have been analyzed to determine the relationship of femoral stem fixation to PPFx revision.

METHODS

All early (≤3 months from index arthroplasty) linked primary and revision hip arthroplasties reported to the AJRR between 2012 and 2017 were analyzed. We evaluated patient demographics, arthroplasty type (hemiarthroplasty vs THA), and stem fixation.

RESULTS

A total of 10,277 linked revisions were reported to the AJRR during 2012-2017. Early PPFx requiring revision occurred in 628 patients (6.1%) due to osteoarthritis (82.4%), femoral neck fracture (12.1%), and other causes (15.6%). Five hundred twenty-nine patients (84%) were treated with THA and 99 patients with hemiarthroplasty (16%). Females (70%) have a higher prevalence of revisions. Fifty-eight percent of patients were ≥70 years of age, and 20% were ≥80 years of age. Patients with cementless stems were 2.6 times (account 94.9% of the fractures, 95% confidence interval 0.59-11.1) more likely to undergo early revision for PPFx than those with cemented fixation, although not statistically significant with its sample size.

CONCLUSION

Mirroring other studies and national registries, there was an association between cementless fixation and PPFx in AJRR. Nevertheless, AJRR data demonstrate a trend of increasing utilization of cementless femoral fixation for THA and hemiarthroplasty, with cementless fixation accounting for 93% of THA stems with early periprosthetic fracture. Additional analysis is needed to better understand this phenomenon, especially in the elderly.

Not all cemented hips are the same: a register-based (NJR) comparison of taper-slip and composite beam femoral stems

Background and purpose - No difference in outcome has been demonstrated comparing cemented taper-slip and composite beam designs in short-term randomised trials; we assessed outcome differences using a registry analysis. Patients and methods - All cemented stems with > 100 implantations were identified in the National Joint Registry of England and Wales from April 1, 2003 to September 31, 2013 and categorised as taper-slip or composite beam. Survival analyses using Kaplan-Meier and Cox regression were performed. Results - We identified 292,987 cemented arthroplasties, of which 16% (47,586) were composite beam stems, with taper-slip stems making up the remainder (n = 245,401). There was a statistically significant increased chance of revision in the composite beam group compared with the taper-slip group (1.7% vs 1.3%, p < 0.001) but statistically no significant differences of survival estimates (p = 0.06). When the 2 groups were segregated to delineate the most implanted model in each category, the differences became more profound with the most implanted taper-slip stem (Exeter V40) showing statistically and clinically significant superior 8-year survival: 97.9% compared with 97.6% for all other taper-slip; 97.5% for the most implanted composite beam (Charnley cemented stem); and 97.7% for all other composite beam. Interpretation - There was an increased incidence of revision for composite beam stems. The most implanted taper-slip stem demonstrated significant survival advantage vs. all other stems.

The design of the cemented stem influences the risk of Vancouver type B fractures, but not of type C: an analysis of 82,837 Lubinus SPII and Exeter Polished stems

Background and purpose - In total hip replacements, stem design may affect the occurrence of periprosthetic femoral fracture. We studied risk factors for fractures around and distal to the 2 most used cemented femoral stems in Sweden. Patients and methods - This is a register study including all standard primary Lubinus SPII and Exeter Polished stems operated in Sweden between 2001 and 2009. The outcome was any kind of reoperation due to fracture around (Vancouver type B) or distal to the stem (Vancouver type C), with use of age, sex, diagnosis at primary THR, and year of index operation as covariates in a Cox regression analysis. A separate analysis of the primary osteoarthritis patient group was done in order to evaluate eventual influence of the surgical approach (lateral versus posterior) on the risk for Vancouver type B fractures. Results - The Exeter stem had a 10-times (95% CI 7-13) higher risk for type B fractures, compared with the Lubinus, while no statistically significant difference was noticed for type C fractures. The elderly, and patients with hip fracture or idiopathic femoral head necrosis, had a higher risk for both fracture types. Inflammatory arthritis was a risk factor only for type C fractures. Type B fractures were more common in men, and type C in women. A lateral approach was associated with decreased risk for Type B fracture. Interpretation - Stem design influenced the risk for type B, but not for type C fracture. The influence of surgical approach on the risk for periprosthetic femoral fracture should be studied further.

HOPE-Trial: Hemiarthroplasty Compared with Total Hip Arthroplasty for Displaced Femoral Neck Fractures in Octogenarians: A Randomized Controlled Trial

BACKGROUND

The choice of primary hemiarthroplasty or total hip arthroplasty in patients ≥80 years of age with a displaced femoral neck fracture has not been adequately studied. As the number of healthy, elderly patients ≥80 years of age is continually increasing, optimizing treatments for improving outcomes and reducing the need for secondary surgery is an important consideration. The aim of the present study was to compare the results of hemiarthroplasty with those of total hip arthroplasty in patients ≥80 years of age.

METHODS

This prospective, randomized, single-blinded trial included 120 patients with a mean age of 86 years (range, 80 to 94 years) who had sustained an acute displaced femoral neck fracture <36 hours previously. The patients were randomized to treatment with hemiarthroplasty (n = 60) or total hip arthroplasty (n = 60). The primary end points were hip function and health-related quality of life at 2 years. Secondary end points included hip-related complications and reoperations, mortality, pain in the involved hip, activities of daily living, surgical time, blood loss, and general complications. The patients were reviewed at 3 months and 1 and 2 years.

RESULTS

We found no differences between the groups in terms of hip function, health-related quality of life, hip-related complications and reoperations, activities of daily living, or pain in the involved hip. Hip function, activities of daily living, and pain in the involved hip deteriorated in both groups compared with pre-fracture values. The ability to regain previous walking function was similar in both groups.

CONCLUSIONS

We found no difference in outcomes after treatment with either hemiarthroplasty or total hip arthroplasty in active octogenarians and nonagenarians with a displaced femoral neck fracture up to 2 years after surgery. Hemiarthroplasty is a suitable procedure in the short term for this group of patients.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Higher periprosthetic fracture rate associated with use of modern uncemented stems compared to cemented stems in femoral neck fractures

INTRODUCTION:

Hemiarthroplasty is the preferred treatment for displaced femoral neck fractures in elderly patients. Recently, short tapered-wedge cementless stems have increasingly been used in this population. However, historic data has consistently shown higher rates of periprosthetic fracture with uncemented stems in hip fracture patients. This study aims to evaluate the rate of periprosthetic fracture requiring re-operation and all-cause mortality between cemented and uncemented femoral stem designs including more recent short tapered-wedge cementless stems in hip fracture patients.

METHODS:

A retrospective chart and radiographic review of patients received bipolar hemiarthroplasty for femoral neck fractures from 2010-2016. Patients biologically (age ≥ 65 years) or physiologically (American Society of Anesthesiologists (ASA) class ≥ 3) elderly were eligible. The uncemented group was subdivided into tapered-wedge stems (a broach only system) and reamed uncemented stems. The primary outcome was periprosthetic fracture requiring re-operation.

RESULTS:

We included 657 patients in total, with 296 and 361 patients in the uncemented and cemented stem groups respectively. In the uncemented group there were 197 tapered-wedge and 99 reamed uncemented stems. There was a significantly higher rate of periprosthetic fracture requiring re-operation in the uncemented group (3.0% vs. 0.6%) ( p ≤ 0.05). There were no significant differences in rates of all-cause mortality, infection or all-cause re-operation.

CONCLUSIONS:

Compared to modern uncemented femoral stem designs, cemented stems yield lower rates of periprosthetic fracture requiring re-operation, without increasing risk of all-cause mortality. Tapered-wedge stems had similar rates of re-operation due to periprosthetic fracture as reamed uncemented stems.

Radiologic outcomes of open reduction and internal fixation for cementless stems in Vancouver B2 periprosthetic fractures

Objective

The aim of this study was to evaluate the radiologic outcomes of open reduction and lateral plating with wiring in the treatment of Vancouver B2 periprosthetic femoral fractures.

Methods

We retrospectively recruited 37 patients treated with ORIF with lateral plating and wiring for Vancouver B2 fractures. The 27 patients (15 men and 12 women; mean age: 70.8 ± 8.3 years) without follow-up loss had achieved complete bony union without notable complications. The average union period was checked after operation with radiologic findings. Radiologic outcomes were evaluated by ipsilateral limb length discrepancy (LLD) and subsidence between immediate postoperative length and length at postoperative 1 year after adjusting for magnification differences. The average distance to which the retained stem sunk down was investigated between immediate postoperative radiographs and final radiographs showing union.

Results

Ten patients could not be evaluated, because of mortality or failure to follow up. The average time to union was 18.3 weeks, and the average distance of stem sinking was 2.5 ± 1.7 mm (range: 0–7.2 mm), which was significantly different between immediate postoperative radiographs and final radiographs. There was no case with loss of reduction or loss of fixation, requiring revision surgery.

Conclusion

Open reduction and lateral plating with wiring as a treatment for Vancouver B2 periprosthetic femoral fractures produced good radiologic outcomes with successful bony union. ORIF can be considered the alternative option for treating patients with Vancouver B2 PPF, instead of stem revision surgery.

Level of evidence

Level IV, Therapeutic study.

More reoperations for periprosthetic fracture after cemented hemiarthroplasty with polished taper-slip stems than after anatomical and straight stems in the treatment of hip fractures

Aims

The aim of this large registry-based study was to compare mid-term survival rates of cemented femoral stems of different designs used in hemiarthroplasty for a fracture of the femoral neck.

Patients and Methods

From the Norwegian Hip Fracture Register (NHFR), 20 532 primary cemented bipolar hemiarthroplasties, which were undertaken in patients aged > 70 years with a femoral neck fracture between 2005 and 2016, were included. Polished tapered stems (n = 12 065) (Exeter and CPT), straight stems (n = 5545) (Charnley, Charnley Modular, and Spectron EF), and anatomical stems (n = 2922) (Lubinus SP2) were included. The survival of the implant with any reoperation as the endpoint was calculated using the Kaplan–Meier method and hazard ratios (HRs), and the different indications for reoperation were calculated using Cox regression analysis.

Results

The one-year survival was 96.0% (95% confidence interval (CI) 95.6 to 96.4) for the Exeter stem, 97.0% (95% CI 96.4 to 97.6) for the Lubinus SP2 stem, 97.6% (95% CI 97.0 to 98.2) for the Charnley stem, 98.1% (95% CI 97.3 to 98.9) for the Spectron EF stem, and 96.4% (95% CI 95.6 to 97.2) for the Charnley Modular stem, respectively. The hazard ratio for reoperation after one year was lower for Lubinus SP2 (HR 0.77, 95% CI 0.60 to 0.97), Charnley (HR 0.64, 95% CI 0.48 to 0.86), and Spectron EF stems (HR 0.44, 95% CI 0.29 to 0.67) compared with the Exeter stem. Reoperation for periprosthetic fracture occurred almost exclusively after the use of polished tapered stems.

Conclusion

We were able to confirm that implant survival after cemented hemiarthroplasty for a hip fracture is high. Differences in rates of reoperation seem to favour anatomical and straight stems compared with polished tapered stems, which had a higher risk of periprosthetic fracture.

Hip arthroplasty in haemophilia: a systematic review

BACKGROUND

Rigorous haemostatic control and careful rehabilitation are essential for haemophilic patients undergoing total hip arthroplasty (THA).

AIM

to examine the current literature regarding THA in patients with haemophilia in order to determine clinical outcomes and complication rates.

METHODS

We included 11 case reports/series and 9 original articles. There was a total of 206 patients who underwent 226 THAs.

FINDINGS

The number of patients enrolled in the selected articles varied from 1 in case reports to 34 in the original articles. Gender was documented in 10. Mean age at surgery was 41 years. Mean follow-up was 73 months (standard deviation [SD] 35 months). All but 4 articles specified whether implants were cemented or uncemented, with 95% being uncemented, 3.5% being cemented, and 1.5% being hybrid (uncemented acetabular component, cemented femoral stem).

CONCLUSION

Controlled hypotensive anaesthesia (to reduce preoperative blood loss), consult with haematologist, precise control of haemostasis status per the guidelines defined by the World Federation joint replacement, can improve the success rate and hip replacement surgery can be performed safely.

Revision for Symptomatic Pseudotumor After Primary Metal-on-Polyethylene Total Hip Arthroplasty with a Standard Femoral Stem

BACKGROUND

Pseudotumor formation following total hip arthroplasty (THA) is a well-known complication mainly associated with metal-on-metal (MoM) bearings and taper corrosion on modular-neck femoral stems. The purpose of this study was to determine the prevalence of revision surgery for symptomatic pseudotumors in a large cohort of patients treated with primary THA with a standard stem and a non-MoM articulation.

METHODS

We included 2,102 patients treated with a total of 2,446 THAs from 1999 until May 2016 in a prospective, observational cohort study. All patients underwent THA with the same uncemented, non-modular-neck femoral stem and metal-on-polyethylene (MoP) (n = 2,409) or ceramic-on-polyethylene (n = 37) articulation. All patients were followed by means of a combination of surgical and medical chart review, follow-up visits, and the Swedish Hip Arthroplasty Register. Metal artifact reduction sequence magnetic resonance imaging (MARS MRI) was used for diagnosis of the pseudotumors, and serum metal ion levels and inflammatory marker levels were measured for all patients who underwent a revision due to pseudotumor.

RESULTS

The prevalence of revision for symptomatic pseudotumor formation was 0.5% (13 cases) at a mean follow-up time of 7 years. The incidence rate was 0.9 case per 1,000 person-years. All 13 revisions were done in patients with an MoP articulation.

CONCLUSIONS

This study demonstrated a 0.5% prevalence of revision due to symptomatic pseudotumor formation in a cohort of patients who underwent THA with a non-MoM construct. Surgeons should be aware that symptomatic pseudotumor formation requiring revision surgery is a tangible complication even after standard MoP THA.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Polished, Collarless, Tapered, Cemented Stems for Primary Hip Arthroplasty May Exhibit High Rate of Periprosthetic Fracture at Short-Term Follow-Up

BACKGROUND

Cemented stems are designed to follow 1 of 2 principles of fixation: composite beams or slide taper. Stems in the latter category have a collarless, polished, tapered (CPT) design and subside into the cement mantle, creating hoop stresses. We compared the rate of periprosthetic fracture (PPF) of stem designed with these 2 principles of fixation. In addition, we examined radiographic factors that may predispose to the development of PPF.

METHODS

We retrospectively reviewed all patients who underwent primary THA by a single surgeon using highly polished cemented stems. PPF rates were compared between CPT stems (follow-up, 21 months; standard deviation [SD], 22) and composite beam stems (follow-up, 21.7 months; SD, 26). Demographic data were compared between patients with and without a PPF. Three preoperative radiographic parameters (canal bone ratio [CBR], canal-calcar ratio, and canal flare index), stem alignment, and cement mantle were compared in match-paired patients with and without a PPF (1:34).

RESULTS

Seven of 1460 THA patients developed a PPF (0.479%); 4 hips of 185 with a CPT stem (2.2%); and 3 of 1275 hips with a composite beam stem (0.23%; P = .0064). Three of the 4 PPFs in the CPT group and none in the composite beam group were classified as Vancouver B2. The CBR in patients with a PPF was 0.50 (SD, 0.07) and 0.43 (SD, 0.07) in the match cohort of hips without PPF (P = .013).

CONCLUSION

CPT stems may be associated with a higher risk of PPF that often require reoperation. An increased CBR may be a risk factor for postoperative PPF.