Cause-Specific Stem Revision Risk in Primary Total Hip Arthroplasty Using Cemented vs Cementless Femoral Stem Fixation in a US Cohort

The effect of fixation type on periprosthetic fractures in high-risk patients who have osteoporosis undergoing total joint arthroplasty

Introduction

Minimizing the burden of periprosthetic fractures (PFF) following total joint arthroplasty (TJA) with regard to morbidity and mortality remains an outcome of interest. Patient and surgical risk factors, including osteoporosis and fixation type, have not truly been optimized in patients undergoing TJA as a means to reduce the risk of PFF. As such, we examined: (1) What percentage of patients who underwent THA and total knee arthroplasty (TKA) met the criteria for osteoporosis screening? (2) How did the 5-year rate of PFF and fragility fracture differ in the high-risk and low-risk groups for osteoporosis between the cemented and cementless cohorts? (3) What percentage of the aforementioned patients received a dual x-ray absorptiometry (DEXA) scan before THA or TKA?

Methods

We queried an all-payer, national database from April 1, 2016 to December 31, 2021, to identify high-risk and low-risk patients who underwent TJA with a cementless or cemented fixation. High-risk patients met at least one of the following criteria: men at least 70 years old, women at least 65 years old, or patients at least 60 years old who have the following: tobacco use, alcohol abuse, body mass index <18.5, prior fragility fracture, chronic systemic corticosteroids, or genetic condition affecting sex hormones or bone mineral density. Exclusion criteria were a diagnosis of malignancy, high-energy events (motor vehicle collision), those who underwent TJA indicated for fracture, patients less than 50 years old, those who had a prior diagnosis of or treatment for osteoporosis, and a minimum follow-up of less than 2 years.

Results

There were 384,783 patients (67.1 %) who underwent cementless TKA and 67,774 patients (11.8 %) who underwent cementless TKA who were considered high risk. Additionally, there were 62,505 patients (10.9 %) who underwent cemented THA and 58,667 patients (10.2 %) who underwent cementless THA and were considered high risk. The cementless cohort had a 5-year periprosthetic fracture risk following TKA of 7.8 % (95 % CI, 5.56 to 10.98) in comparison to 4.30 % in the cemented cohort (85 % CI, 3.98 to 4.65), P < 0.0001. The high-risk cementless cohort had a 5-year periprosthetic fracture risk following THA of 7.9 % (95 % confidence interval (CI), 6.87 to 9.19) in comparison to 7.78 % in the cemented cohort (85 % CI, 6.77 to 8.94), P < 0.0001.

Conclusion

There is an increased risk of PFF at 5 years following TKA in patients at high risk for osteoporosis undergoing cementless fixation in comparison to cemented fixation. There is an increased risk of PFF at 5 years following THA in patients at high risk for osteoporosis for both cementless fixation and cemented fixation, but no clinically meaningful difference between the two groups. Addressing the shortcomings of the underutilization of bone density scans and better selecting appropriate patients for TJA based on bone quality and fracture risk can help expedite the process of improving the current state of practice.

Cemented Versus Cementless Femoral Fixation for Total Hip Arthroplasty Following Femoral Neck Fracture in Patients Aged 65 and Older

BACKGROUND

Femoral neck fractures are common in individuals over 65, necessitating quick mobilization for the best outcomes. There's ongoing debate about the optimal femoral component fixation method in total hip arthroplasty (THA) for these fractures. Recent U.S. data shows a preference for cementless techniques in over 93% of primary THAs. Nonetheless, cemented fixation might offer advantages like fewer revisions, reduced periprosthetic fractures, lesser thigh pain, and enhanced long-term implant survival for those above 65. This study compares cementless and cemented fixation methods in THA, focusing on postoperative complications in patients aged 65 and older.

METHODS

We analyzed a national database to identify patients aged 65+ who underwent primary THA for femoral neck fractures between 2016 and 2021, using either cementless (n = 2,842) or cemented (n = 1,124) techniques. A 1:1 propensity-matched analysis was conducted to balance variables such as age, sex, and comorbidities, resulting in two equally sized groups (n = 1,124 each). We evaluated outcomes like infection, venous thromboembolism (VTE), wound issues, dislocation, periprosthetic fracture, etc., at 90 days, 1 year, and 2 years post-surgery. A P-value < 05 indicated statistical significance.

RESULTS

The cemented group initially consisted of older individuals, more females, and higher comorbidity rates. Both groups had similar infection and wound complication rates, and aseptic loosening. The cemented group, however, had lower periprosthetic fracture rates (2.5 versus 4.4%, P = .02) and higher VTE rates (2.9 versus 1.2%, P = .01) at 90 days. After 1 and 2 years, the cementless group experienced more aseptic revision surgeries.

CONCLUSIONS

This study, using a large, national database and propensity-matched cohorts, indicates that cemented femoral component fixation in THA leads to fewer periprosthetic fractures and aseptic revisions, but a higher VTE risk. Fixation type choice should consider various factors, including age, sex, comorbidities, bone quality, and surgical expertise. This data can inform surgeons in their decision-making process.

Analysis of Postoperative Complication and Revision Rates and Mid- to Long-Term Implant Survival in Primary Short-Stem Total Hip Arthroplasty

Background/Objectives: Short-stem prostheses were introduced as an alternative to conventional straight-stem prostheses. Despite their benefits, including minimally invasive approaches, soft-tissue- and bone-sparing implantation, and physiological load transfer to the metaphysis, data on postoperative complication and revision rates as well as on implant survival are scarce. Methods: A retrospective analysis of 1327 patients who underwent primary total hip arthroplasty (THA) using the Metha® short stem between 2006 and 2023 was conducted. Complication and revision rates were analysed for the intraoperative, direct postoperative, and follow-up episodes. Implant survival was analysed with the endpoint of all-cause stem revision. Results: Intraoperative complications were observed in 3.77% of the cases and included 44 hairline cracks and 6 fractures. In 15 cases (30.0%), conversion to a straight-stem or revision implant was necessary. The direct postoperative complication rate was 2.44%, and 11 revision procedures were performed during inpatient stay (0.84%). Mean follow-up was 7 years (range 1-17). During follow-up, femoral component revision was performed in 60 cases. Aseptic loosening and stem subsidence accounted for a combined percentage of 80% of all indications. Implant survival rate was 95.66% after 5 years, 95.58% after 10 years, and 95.50% after 15 years. Conclusions: Our study provides a comprehensive analysis of postoperative complication and revision rates in a large sample undergoing primary short-stem THA. Postoperative complication rates were favourable, and the long-term implant survival rates were comparable to conventional straight-stem prostheses. Therefore, short-stem THA may be considered an alternative for younger patients.

Impact of fixation method on femoral bone loss: a retrospective evaluation of stem loosening in first-time revision total hip arthroplasty among two hundred and fifty five patients

PURPOSE

Implant loosening represent the most common indication for stem revision in hip revision arthroplasty. This study compares femoral bone loss and the risk of initial revisions between cemented and uncemented loosened primary stems, investigating the impact of fixation method at primary implantation on femoral bone defects.

METHODS

This retrospective study reviewed 255 patients who underwent their first revision for stem loosening from 2010 to 2022, receiving either cemented or uncemented stem implants. Femoral bone loss was preoperatively measured using the Paprosky classification through radiographic evaluations. Kaplan-Meier analysis estimated the survival probability of the original stem, and the hazard ratio assessed the relative risk of revision for uncemented versus cemented stems in the first postoperative year and the following two to ten years.

RESULTS

Cemented stems showed a higher prevalence of significant bone loss (type 3b and 4 defects: 32.39% vs. 2.72%, p < .001) compared to uncemented stems, which more commonly had type 1 and 2 defects (82.07% vs. 47.89%, p < .001). In our analysis of revision cases, primary uncemented stems demonstrated a 20% lower incidence of stem loosening in the first year post-implantation compared to cemented stems (HR 0.8; 95%-CI 0.3-2.0). However, the incidence in uncemented stems increased by 20% during the subsequent years two to ten (HR 1.2; 95%-CI 0.7-1.8). Septic loosening was more common in cemented stems (28.17% vs. 10.87% in uncemented stems, p = .001). Kaplan-Meier analysis indicated a modestly longer revision-free period for cemented stems within the first ten years post-implantation (p < .022).

CONCLUSION

During first-time revision, cemented stems show significantly larger femoral bone defects than uncemented stems. Septic stem loosening occurred 17.30% more in cemented stems.

Cemented Versus Cementless Femoral Fixation for Total Hip Arthroplasty Following Osteoarthritis

BACKGROUND

The mode of femoral fixation for primary total hip arthroplasty (THA) is undetermined, with reported outcomes favoring different fixation methods. This study aimed to compare postoperative complications between cemented and cementless fixation at 90 days, 1 year, and 2 years in patients aged 65 years of age and older undergoing THA for osteoarthritis.

METHODS

Using an all-payer, national database, patients 65 years and older undergoing primary THA, either with cementless (n = 56,701) or cemented (n = 6,283) femoral fixation for osteoarthritis were identified. A 1:1 propensity-matched analysis for age, sex, comorbidity index, alcohol abuse, tobacco use, obesity, and diabetes was performed, resulting in n = 6,283 patients in each cohort. Postoperative outcomes, including postoperative periprosthetic joint infection, aseptic revision, surgical site infection, pulmonary embolism, venous thromboembolism, wound complications, dislocation, periprosthetic fracture, and aseptic loosening were assessed.

RESULTS

The cemented cohort had higher rates of infection (4.5 versus 0.8%, odds ratio [OR] 5.9, 95% confidence interval [CI] 4.33 to 7.93, P < .001), aseptic revision (2.9 versus 2.0%, OR 1.47, 95% CI 1.17 to 1.85, P = .001), venous thromboembolism (1.8 versus 1.3%, OR 1.40, 95% CI 1.05 to 1.87, P < .001), and aseptic loosening (1.5 versus 0.7%, OR 2.31, 95% CI 1.60 to 3.32, P < .001) at 90-days. At 1 and 2 years, the cemented cohort had higher rates of infection, aseptic revision, and aseptic loosening (all P < .001). Rates of periprosthetic fracture were similar at all time points (all P < .001).

CONCLUSIONS

Cemented fixation had higher rates of infection, aseptic loosening, and aseptic revision. This finding supports the current use of cementless fixation, but the ultimate decision regarding fixation type should be based on the proper optimization of the patient's comorbidities and bone quality.

Are current rates of uncemented fixation in total hip arthroplasty supported by the literature? An update on the uncemented paradox

The optimal fixation method in total hip arthroplasty (THA) remains controversial. Initial concerns related to the long-term performance of cement fixation as well as cement disease led to the development of cementless implants, and registry data has indicated that the use of this type of fixation has increased in recent years. However, data from these same registries has not shown any improvement in outcomes when compared to cement fixation. On the contrary, while similar outcomes are seen when comparing these fixation types in younger patients (<70 years of age), cementless fixation has shown increased implant failure and revision rates in elderly patients (>70 years of age). Given the increased projected volume of THA in the United States over the next decade, it is important to utilise available data to make clinical decisions that minimise not only individual patient harm, but also the burden on the healthcare system itself. This review provides an overview of currently available outcomes data comparing cement and cementless fixation, as well as an updated analysis of current trends in fixation use in THA. We furthermore provide a comprehensive technique guide to help surgeons optimise cement fixation of the femoral component for THA and hemiarthroplasty.

Periprosthetic Hip Fractures around the Stem: Can the Stem Design Affect Fracture Features?

Background: Total hip arthroplasty is one of the most successful orthopedic surgeries; nevertheless, many of these surgeries are the causes of failure, and among them, periprosthetic fractures are one of the major causes of revision. Our study focuses on periprosthetic hip fractures with two different stem designs. The aim of the study was to analyze the obtained results, focusing on the features of periprosthetic stem fractures observed. Methods: We retrospectively reviewed periprosthetic fractures occurring between 2010 and 2023, involving Alloclassic® or CLS® uncemented femoral stems. We analyzed demographic data, proximal femur morphology, and the fracture type. Results: We identified 97 patients. Considering the proximal femur morphology, we found that there was statistically significant prevalence of Dorr A proximal femur morphology in the CLS® group and of Dorr C in the Alloclassic® group. Considering the distribution of the fracture pattern, we reported a non-statistically significant prevalence of the fracture pattern with stable stems in the CLS® group. Conclusions: The choice of the prosthetic design of the femoral stem is a crucial element when planning total hip arthroplasty. However, we found a non-statistically significant difference between the two stems considered, raising questions about the real role of stem design as a primary determinant of periprosthetic hip fractures.

Short versus conventional straight stem in uncemented total hip arthroplasty: functional outcomes up to 5 years and survival up to 12 years: secondary results of a randomized controlled trial

BACKGROUND AND PURPOSE

To date, the mid- and long-term outcomes of the Collum Femoris Preserving (CFP) stem compared with conventional straight stems are unknown. We aimed to compare physical function at a 5-year follow-up and implant survival at an average of 10-year follow-up in an randomized controlled trial (RCT).

METHODS

This is a secondary report of a double-blinded RCT in 2 hospitals. Patients aged 18-70 years with hip osteoarthritis undergoing an uncemented primary THA were randomized to a CFP or a Zweymüller stem. Patient-reported outcomes, clinical tests, and radiographs were collected at baseline, 2, 3, 4, and 5 years postoperatively. Primary outcome was the Hip disability and Osteoarthritis Outcome Score (HOOS) function in activities of daily living (ADL) subscale. Secondary outcomes were other patient-reported outcomes, clinical tests, adverse events, and implant survival. Kaplan-Meier and competing risk survival analyses were performed with data from the Dutch Arthroplasty Registry.

RESULTS

We included 150 patients. Mean difference between groups on the HOOS ADL subscale at 5 years was -0.07 (95% confidence interval -5.1 to 4.9). Overall survival was 92% for the CFP and 96% for the Zweymüller stem. No significant difference was found.

CONCLUSION

No significant differences were found in physical function at 5-year and implant survival at 10-year follow-up between the CFP and Zweymüller stems. When taking cup revisions into account, the CFP group showed clinically inferior survival.

Sex-Specific Implant Fixation Can Reduce Revision Rates in Total Hip Arthroplasty: Evidence From the Swiss National Joint Registry

BACKGROUND

Patient's sex is considered a risk factor for revision following primary total hip arthroplasty (THA), but sex-specific treatment guidelines are lacking. The purpose was to assess sex-specificity of risk factors for periprosthetic femoral fractures (PFFs) and aseptic stem loosening (ASL) in a nationwide register study.

METHODS

All uncemented and hybrid THAs for hip osteoarthritis registered in the Swiss National Joint Registry were considered. 86,423 THAs were analyzed. Comparable THA subsets for both sexes were obtained through propensity score matching (1:1). A sex-specific analysis of risk factors for early PFF or ASL was performed using recursive partitioning analyses.

RESULTS

In women, PFFs were most significantly associated with uncemented THA fixation (P < .0001) and age (P < .01, threshold: 70.5 years). The ASLs were solely associated with patient age of <65 years (P = .023). In men, PFFs were associated exclusively with an American Society of Anesthesiologists (ASA) score >2 (P = .026). The ASLs were not correlated to any of the potential risk factors analyzed. A mathematical simulation indicated that avoiding uncemented THA fixation in women ≥70.5 years of age decreased the number of revisions within the observational period by 21% in this subset and by 4.9% in the entire patient population.

CONCLUSION

Uncemented THA should be avoided in women >70.5 years due to the increased risk of early PFF, while the mode of stem fixation did not influence revision risk in men. A sex-specific regimen for THA fixation has the potential to markedly reduce early THA revision rates.

The risk analysis of perioperative complications of cementless hip arthroplasty in octogenarians

INTRODUCTION

Hip arthroplasty is exposed to demographic change as patients age. Analysis of risk factors for surgical treatment decisions in the group of ≥ 80-year-old patients is crucial. Healthcare systems in developed countries are being tested medically and financially by the ageing population. Therefore, this study analysed the perioperative complications of cementless primary hip arthroplasty in octogenarians and compared them with patients aged ≤ 60 years.

METHODS

A retrospective data analysis of the year 2017 was done in a maximum care hospital of General Orthopaedic Surgery. Patients aged ≥ 80 years or ≤ 60 years with primary cementless hip arthroplasty were included. The outcome of interest was surgery-related and systemic complications, the development of haemoglobin and the incidence of blood transfusion after cementless primary hip arthroplasty in octogenarians during the hospitalisation and the follow-up treatment. Chi-square tests and Fischer's exact test were used for nominal variables. The two-factorial variance analysis-mixed model was used for Hb analyses and the Welch test for group comparison for metric parameters.

RESULTS

There was a significantly increased incidence of systemic complications during hospitalisation in the ≥ 80-year-old patients (phi 0.26; Std. Ri - 0.8 (A), 2.2 (B); p = 0.007), as well as a significantly increased rate of blood transfusions (phi 0.403; Std. Ri - 1.3 (A), 3.2 (B); p = < 0.001). No clustered pre-existing conditions in the ≥ 80-year-old patients pointed out a significant association with the incidence of systemic complications. Surgery-related complications showed no significant difference during hospitalisation and follow-up treatment.

CONCLUSION

The study reveals that primary cementless hip prosthesis implantation is a safe procedure without increased incidence of surgery-related complications. Increased attention should be paid to interdisciplinary preoperative optimisation (adjustment of blood pressure, blood transfusions, if necessary, safe exclusion of urinary tract infections) and postoperative care of octogenarians (tight laboratory examinations, geriatric co-attendance).

Cemented versus Cementless Total Hip Arthroplasty for Femoral Head Osteonecrosis: A Study Based on National Claim Data in South Korea

INTRODUCTION

The purpose of this study was to compare the rates of revision, periprosthetic joint infection (PJI), and periprosthetic fracture (PPF) between patients with osteonecrosis of the femoral head (ONFH) undergoing noncemented total hip arthroplasty (THA) and cemented THA using a national claim data in South Korea.

METHODS

We identified patients who received THA for ONFH from January 2007 to December 2018 using ICD diagnosis codes and procedural codes. Patients were categorized into two groups according to the fixation method: with or without cement. The survivorship of THA was calculated using the following end points: revision of both the cup and stem, revision of the single component, any type of revision, PJI, and PPF.

RESULTS

A total of 40,606 patients: 3,738 patients (9.2%) with cement and 36,868 patients (90.7%) without cement, received THA for ONFH. The mean age of the noncemented fixation group (56.2 ± 13.2 years) was significantly lower than that of the cemented fixation group (57.0 ± 15.7 years, P = 0.003). The risk of revision and PJI was notably higher in cemented THA (hazard ratio: 1.44 [1.21 to 1.72] and 1.66 [1.36 to 2.04], respectively). Noncemented THA had a higher 12-year survivorship compared with cemented THA with any revision and PJI as the end point.

DISCUSSION

Noncemented fixation had better survivorship than cemented fixation in patients with ONFH.

Cemented Femoral Fixation in Total Hip Arthroplasty Reduces the Risk of Periprosthetic Femur Fracture in Patients 65 Years and Older: An Analysis from the American Joint Replacement Registry

BACKGROUND

Periprosthetic femur fracture (PPFx) is a devastating complication after total hip arthroplasty (THA). Despite concerns for increased PPFx, cementless fixation predominates in the United States (US). This study utilized the American Joint Replacement Registry (AJRR) to compare PPFx risk between cemented and cementless femoral fixation for THA.

METHODS

An analysis of primary THA cases in patients aged 65 years and older was performed with AJRR data linked to Centers for Medicare and Medicaid Services (CMS) data from 2012 to 2020. Analyses compared cemented to cementless femoral fixation. We identified 279,052 primary THAs, 266,040 (95.3%) with cementless and 13,012 (4.7%) with cemented femoral fixation. Cox proportional hazard regression analyses evaluated the association of fixation and PPFx risk, while adjusting for sex, age and competing risk of mortality. Cumulative incidence function (CIF) survival curves evaluated time to PPFx.

RESULTS

Age ≥ 80 years (P<0.0001) and women (P<0.0001) were associated with PPFx. Compared to cemented stems, cementless stems had an elevated risk of PPFx (Hazards Ratio 7.70, [95% Confidence interval 3.2-18.6], P<0.0001). The CIF curves demonstrated an increased risk for PPFx across all time points for cementless stems, with equal magnitude of risk to eight years.

CONCLUSION

Cementless femoral fixation in THA continues to predominate in the US, with cementless femoral fixation demonstrating increased risk of PPFx in patients 65 years or older. Surgeons should consider greater use of cemented femoral fixation in this population to decrease the risk of PPFx.

Single Wedge Femoral Stem Designs are Associated With a Higher Risk for Revision After Cementless Primary Total Hip Arthroplasty

BACKGROUND

Cementless total hip arthroplasty (THA) femoral stems are the most commonly selected prostheses in the United States. Optimal stem geometry remains controversial with excellent survivorship reported for many designs. We compared cause-specific stem revision of single-wedge versus double-wedge designs from a multicenter US cohort.

METHODS

Data from an integrated healthcare network's total joint replacement registry were used to conduct a cohort study. Primary elective cementless THAs were identified (2001 to 2018). Implant exposure groups were classified by design geometry using the system proposed by Khanuja et al. Type 1 single-wedge (n = 11,082) and type 2 double-wedge (n = 32,380) designs were compared, and other design types were excluded; the final study cohort comprised 43,462 THAs. Cause-specific multivariable Cox regressions were used to evaluate risk for revision due to infection or aseptic reasons, including loosening, instability, periprosthetic fracture, or other reasons.

RESULTS

After adjustment for covariates, a higher aseptic revision risk was observed for type 1 when compared to type 2 designs (hazard ratio = 1.91, 95% confidence interval = 1.33-2.75). When looking at specific revision reasons, revision for aseptic loosening (hazard ratio = 3.46, 95% confidence interval = 2.24-5.34) was higher for type 1 versus type 2 designs. No differences were found for septic revision, instability, periprosthetic fracture, or revisions for other reasons.

CONCLUSIONS

Type 1 single-wedge designs were found to have a higher risk of revision due to aseptic loosening relative to type 2 double-wedge designs. Femoral stem geometry should be considered when selecting a cementless femoral implant.

LEVEL OF EVIDENCE

Level III.

Hip Arthroplasty Femoral Stem Designs and Their Association With Early Postoperative Periprosthetic Femoral Fractures

BACKGROUND

Periprosthetic femoral fractures (PFFs) in total hip arthroplasty (THA), especially those in contact with the diaphyseal stem, carry high morbidity. This study evaluated how stem design influences the risk of early Vancouver B PFF or other PFF requiring operative intervention after THA.

METHODS

A multicenter, retrospective study of 3,433 primary cementless THAs performed from 2014 to 2021 included 2,302 single-taper (micro M/L [n = 1,169]; M/L [n = 1,133]) and 1,131 double-taper (fit-and-fill [n = 420]; compaction-collared [n = 711]) stems. Mean follow-up was 2.2 years (range, 0.3 to 6.5 years). Primary outcomes were Vancouver B and surgically treated postoperative PFFs among differing femoral stems. Secondary outcomes included rates of intraoperative and postoperative Vancouver A and C PFFs.

RESULTS

Forty five postoperative PFFs (1.3%) occurred within 8.8 weeks (median), 25 of which were Vancouver B (0.7%) and 20 total PFFs that required operative intervention (0.6%). Compaction-collared stems had a decreased risk of Vancouver B (hazard ratio 0.18, 95% confidence interval: 0.03-0.97 P = .044) and any surgically treated PFF (hazard ratio 0.10, 95% confidence interval: 0.01-0.95; P = .037). Intraoperative PFFs were most common with fit-and-fill stems (3.6%, P < .001) and Vancouver A with compaction-collared stems (1.8%, P < .001). The cohort with PFF had a higher Charlson comorbidity index (P = .004), more women (P = .001), more Dorr A or C femora (P = .013), and more posterior or lateral surgical approaches compared to those without PFF (P ≤ .001).

CONCLUSION

After controlling for confounding variables, compaction-collared stems had a significantly lower risk of postoperative Vancouver B and PFF requiring operative treatment than single-taper and double-taper stems.

Effectiveness of prophylactic double-looped wiring in cementless Hip arthroplasty: A biomechanical study in osteoporotic bone model using impaction simulation system

BACKGROUND

Periprosthetic femoral fracture (PFF) is well-known complication in cementless hip arthroplasty (HA), especially in the elderly with osteoporosis. To prevent intraoperative PFFs during HA, prophylactic cerclage wiring on the calcar area during femoral broaching and implant insertion is recommended. However, biomechanical data on the benefits of cerclage wiring in osteoporotic bone during impaction are limited and controversial. This study aimed to assess the efficacy of prophylactic double-looped cerclage wiring (PDLCW) during femoral broaching in the osteoporotic bone model with an impaction simulation system.

METHODS

Fifteen osteoporotic femur models were prepared and allocated to three groups; control group (no cerclage), PW group (received PDLCW), and CC+PW group (prepared as having calcar crack and received PDLCW). All femurs were broached under impaction force that sequentially increased until the visible fracture or calcar crack propagation was visible. The primary outcomes were mallet impaction force (MIF-CF) and mallet velocity (MV-CF) at the time of calcar fracture. The secondary outcomes were calcar fracture pattern and subsidence during calcar fracture (S-CF).

RESULTS

PW group showed a significant increase in average MIF-CF, by 40.4% and 120.2% (p<0.001) compared to the control and CC+PW groups, respectively. The average MV-CF in PW group was also significantly greater, 13.1% and 64.6% (p<0.001), compared to the control and CC+PW groups, respectively. Control group revealed significantly greater incidence of complete calcar fracture (60% vs. 0% vs. 0%, p = 0.024), and the highest S-CF compared to those in the PW and CC+PW groups (10.6 ± 6.0 mm, 6.7 ± 4.4 mm, and 1.3 ± 2.0 mm, p = 0.020).

CONCLUSIONS

This study showed that PDLCW significantly improved hoop stress resistance by increasing the calcar fracture threshold related to mallet impaction, decreasing the risk of complete calcar fracture.