Still no single gold standard for using cementless femoral stems routinely in total hip arthroplasty

What features of stem increase the risk of intraoperative femoral fracture during cementless primary hip arthroplasty?

INTRODUCTION

Cementless fixation has become increasingly popular in hip arthroplasty due to its shorter operation time, easier technique, biologic fixation, and avoidance of bone cement implantation syndrome compared to cemented fixation. However, intraoperative periprosthetic femoral fracture (IOPFx) is a disconcerting complication during cementless hip arthroplasty. Our purpose was to identify the features of cementless stem that increase the risk of IOPFx during primary hip arthroplasty.

MATERIALS AND METHODS

We retrospectively reviewed all 4806 hip arthroplasties that was performed in a single institution from May 2003 to December 2020. Age at the index arthroplasty, sex, body mass index, physical status, ambulatory function, side of the operation, operational history, cause of the index arthroplasty, type of arthroplasty, surgical approach, surgeon, implant information, and events during the operation were investigated. The shoulder geometry and length of stem were also reviewed. The event of interest was narrowed down to IOPFx among various records of intraoperative events.

RESULTS

We found IOPFx of 2.6% among all the hips operated with cementless stem. In the multivariable analysis, female (OR = 1.52), childhood hip disease (OR = 2.30), stove-pipe femur (OR = 2.43), combined approach (OR = 2.60), and standard length of stem (OR = 1.59) were found to be significant risk factors of IOPFx.

CONCLUSIONS

In conclusion, a stem with a standard length is significantly associated with risk of IOPFx compared to a shortened stem. These findings highlight the importance of careful consideration in terms of the risk of IOPFx when standard length cementless stem is chosen.

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.

The use of uncemented stems in femoral neck fractures in elderly patients: A comparative study of 671 cases

INTRODUCTION

The use of cemented stems in elderly patients is associated with the risk of intraoperative embolic complications. Uncemented stems eliminate this risk, but their use is controversial because of the risk of mechanical complications, with estimated subsidence between 3.6 and 30% and periprosthetic fractures between 2.1 and 11% at 6 weeks. A retrospective multicenter comparative study was conducted using a propensity score analysis to evaluate mechanical performances of uncemented stems in femoral neck fractures in elderly patients to (1) compare the risk of mechanical complications and (2) assess the use of metaphyseal-anchored stems for this indication.

HYPOTHESIS

There is no difference in the risk of mechanical complications, intraoperatively or postoperatively, between these stems.

MATERIALS AND METHODS

We conducted a multicenter retrospective comparative study including 358 uncemented and 313 cemented stems. The mean age was 84.5 years [83.9-85.1]. The inclusion criteria were patients 70 years and older and a follow-up of at least 6 weeks. The primary endpoint was a composite endpoint comprised of stem subsidence≥2mm or periprosthetic fracture (up to 3 months postoperatively). The secondary endpoints were infection, stem subsidence≥2mm, and operative time. These endpoints were analyzed using a propensity score to control confounding factors. A secondary analysis used the same endpoints to compare metaphyseal-anchored (short stems) versus Corail-like stems.

RESULTS

After adjusting for the propensity score, we found 11.17% mechanical complications in the uncemented group (n=40, 5.59% subsidence, and 5.59% fractures) versus 13.42% for the cemented group (n=42, 7.99% subsidence, and 5.43% fractures). There was no statistically significant difference between the 2 values (Odds Ratio [OR]=0.64 [95% Confidence Interval [CI]: 0.14-2.85] [p=0.7]). The mortality rate due to cement embolism was 1%. There was no difference in the rate of subsidence (OR=0.55 [95% CI: 0.02-12.5] [p=0.7]), periprosthetic fracture (OR=0.65 [95% CI: 0.13-3.12] [p=0.7]) or infection (OR=0.71 [95% CI: 0.32-1.55] [p=0.4]). However, the operative times were longer in the cemented group (p=0.03 for hemiarthroplasties [mean additional time 16minutes] and p=0.02 for total hip arthroplasties [mean additional time 22minutes]). No difference was observed between the metaphyseal-anchored (short stems) and Corail-like stems regarding operative time, rate of infection, and rate of stem subsidence or periprosthetic fractures.

DISCUSSION

This is one of the first studies to highlight cemented stem subsidence when used for femoral neck fractures in elderly patients. Using uncemented stems in this indication is still warranted, especially since they do not bring about more mechanical complications in the first few months. Metaphyseal-anchored short stems seem to give the same results as "standard" stems. However, these findings need to be assessed in the longer term.

LEVEL OF EVIDENCE

III; retrospective comparative study.

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.

Differences in periprosthetic bone mineral density tendencies with Types 1 and 3C stems in bipolar hemiarthroplasty following hip fracture

The purpose of this study was to compare the periprosthetic bone mineral density (BMD) changes in the patients who underwent bipolar hemiarthroplasty (BPHA) for geriatric femoral neck fracture between two major different types of cementless femoral stems. A total of 93 patients (96 hips) who underwent BPHA for femoral neck fracture were categorized into two groups: Type 1 (42 patients, 44 hips), and Type 3C stem (51 patients, 52 hips). We investigated the annual follow-up trends of periprosthetic BMD at each Gruen zone during minimum postoperative 5-years; moreover, we compared the trends of periprosthetic BMD between both groups. The mean follow-up period was 7.1 years. In both groups, the overall BMD at the last follow-up had decreased compared with the baseline. In those with the Type 1 stem, BMD in the lateral femoral meta-diaphysis significantly decreased at 1-year follow-up after surgery. In those with Type 3C stem, BMD in the lateral femoral metaphysis postoperatively decreased after 3-years, whereas the BMD in the mediolateral femoral diaphysis drastically decreased postoperative 1-year period and plateaued thereafter. Different tendencies according to stem design were observed obviously in the postoperative BMD change of the proximal femur in patients who underwent BPHA for geriatric femoral neck fracture.

Cerclage wire or positional cortical screw for the treatment of intraoperative calcar fractures during primary total hip arthroplasty? A biomechanical study

BACKGROUND

During primary total hip arthroplasty, intra-operative calcar fractures have been historically treated with cerclage wires. However, interfragmentary screw fixation technique can possibly achieve the same results with technical advantages. The aim of this biomechanical study was to assess stability of calcar fractures fixed using interfragmentary screw technique compared to a traditional cerclage system specifically in context of total hip arthroplasty.

METHODS

Thirty-two periprosthetic fractures were reduced using either a single cerclage cable or an intracortical positional screw perpendicular to the fracture line. Axial and torsional load testing was terminated after experimental model failure.

FINDINGS

No significant difference was obtained for all output parameters when comparing cerclage wires versus interfragmentary screw fixation respectively. Load at failure: 8043 ± 712 N vs 7425 ± 854 N (p = 0.115). Load at calcar fracture propagation: 6240 ± 2207 N versus 6220 ± 966 N (p = 0.668). Maximum stiffness before failure: 617 ± 115 N/mm vs 839 ± 175 N/mm (p = 0.100) and stiffness at calcar fracture propagation reached 771 ± 153 Nmm vs 886 ± 129 N/mm (p = 0.197). Torque to failure levels obtained were 59.4 ± 7.1 N*m vs 60.9 ± 12.0 N*m (p = 0.908). Torque to calcar fracture propagation, 51.6 ± 6.1 N*m vs 48.5 ± 9.8 N*m (p = 0.298). Torsional stiffness at failure, 0.38 ± 0.03 N*m\deg. vs 0.43 ± 0.13 N*m\deg. (p = 0.465). Torsional stiffness at calcar fracture propagation were 0.37 ± 0.03 N*m\deg. vs 0.45 ± 0.17 N*m\deg. (p = 0.462).

INTERPRETATION

The strength of fixation and stability of the implant were similar for both techniques. In the synthetic bone model tested, using an interfragmentary screw conveyed similar stability to the constructs in the management of an intra-operative medial calcar fractures. Thus, potentially giving surgeons an alternative option for intraoperative fracture fixation during primary total hip arthroplasty.

The short-term outcomes of cementless stem for hip arthroplasty in the elderly patients: comparison with patients < 65 years

OBJECTIVE

The use of cement or cementless femoral stem prosthesis for hip arthroplasty in elderly patients has been controversial. This study investigated the efficacy and safety of cementless femoral stem in elderly patients (age ≥ 65 years).

METHODS

The short-term efficacy of primary hip arthroplasty with cementless femoral stem in our hospital from January 2014 to June 2021 was retrospectively analyzed. Patients were divided into two groups according to age: young group (< 65 years) and the elder group (≥ 65 years). The evaluation index was the Harris Hip score (Harris), postoperative femoral stem prosthesis sinking distance and femoral plant-related complications (periprosthetic fracture, prosthesis loosening, infection, dislocation, etc.).

RESULTS

There were 72 cases of 86 hips in the young group and 83 cases of 92 hips in the elder group. The recovery trend of functional score in the elder group was similar to that in the young group, and the Harris score increased from (38.35 ± 18.21) before surgery to (86.91 ± 12.55) at last follow-up (p < 0.01). Compared with the two groups at the same time of 3 months, 6 months and 12 months after operation, the sinking distance of the elder group was significantly greater (P < 0.05). Even in the elder group, there was a significant difference in sinking distance between 6 and 3 months after surgery (2.44 ± 0.49 mm vs 2.10 ± 0.65 mm, P = 0.004). However, there was no significant difference between 12 and 6 months (2.53 ± 0.53 mm vs 2.44 ± 0.49 mm, P = 0.40). A total of 10 patients in the elder group and 6 patients in the young group had a complication event (P = 0.36).

CONCLUSIONS

Elderly patients with cementless femoral stems can achieve metal-bone integration slightly longer than young patients, but short-term clinical outcomes can be restored to a satisfactory level with adequate safety. However, the long-term efficacy still needs to be verified by multicenter, large sample size and prospective clinical follow-up results.

Survivorship of the retained femoral component after revision total hip arthroplasty: A systematic review and meta-analysis

Objective

This systematic review and meta-analysis aimed to estimate re-revision rates of retained femoral components after revision of total hip arthroplasty (THA).

Methods

Papers were searched in the PubMed, Embase, Web of Science, and Cochrane Library databases with predetermined keywords from January 2000 to January 2022. The studies reporting the re-revision rates of retained stems after revision THA were identified. Pooled rates of re-revision for any reason and aseptic loosening were calculated using a random-effects model or a fixed-effects model based on the results of heterogeneity assessment after the Freeman–Tukey double-arcsine transformation. A meta-regression was performed to explore potential sources of heterogeneity.

Results

There were 20 studies with 1,484 hips that received the isolated cup revision with the femoral component retained. The pooled re-revision rate of retained stems was 1.75% [95% confidence interval (CI) 0.43%–3.65%]. The re-revision rate of retained stems due to aseptic loosening was 0.62% (95% CI, 0.06%–1.55%). The meta-regression showed that the fixation type (cemented or cementless) was related to the re-revision rate for any reason and the re-revision rate for aseptic loosening.

Conclusion

Based on the existing evidence, the isolated cup revision with a stable stem in situ yields low re-revision rates. The cement status of retained stems may influence the survivorship of stems.

Gunshot Wound to the Hip Resulting in a Femoral Head and Acetabulum Fracture Treated With Open Reduction and Internal Fixation and Bipolar Hemiarthroplasty

Combined fractures of the femoral head and acetabulum due to ballistic injuries are rare injuries, especially in the elderly. We present a case of a 70-year-old female who sustained a gunshot wound to the left hip, resulting in a comminuted femoral head fracture and posterior wall acetabular fracture. She was treated with open reduction and internal fixation of the acetabulum, as well as bipolar hemiarthroplasty for treatment of her femoral head fracture. At her 18-month follow-up visit, the patient was doing well and had no complaints.

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.

Similar Healthcare Utilization and 1-Year Patient-Reported Outcomes between Cemented and Cementless Primary Total Knee Arthroplasty: A Propensity Score-Matched Analysis

Cementless fixation for total knee arthroplasty (TKA) has gained traction with the advent of newer fixation technologies. This study assessed (1) healthcare utilization (length of stay (LOS), nonhome discharge, 90-day readmission, and 1-year reoperation); (2) 1-year mortality; and (3) 1-year joint-specific and global health-related patient-reported outcome measures (PROMs) among patients who received cementless versus cemented TKA. Patients who underwent cementless and cemented TKA at a single institution (July 2015-August 2018) were prospectively enrolled. A total of 424 cementless and 5,274 cemented TKAs were included. The cementless cohort was propensity score-matched to a group cemented TKAs (1:3-cementless: n = 424; cemented: n = 1,272). Within the matched cohorts, 76.9% (n = 326) cementless and 75.9% (n = 966) cementless TKAs completed 1-year PROMs. Healthcare utilization measures, mortality and the median 1-year change in knee injury and osteoarthritis outcome score (KOOS)-pain, KOOS-physical function short form (PS), KOOS-knee related quality of life (KRQOL), Veteran Rand (VR)-12 mental composite (MCS), and physical composite (PCS) scores were compared. The minimal clinically important difference (MCID) for PROMs was calculated. Cementless TKA exhibited similar rates of median LOS (p = 0.109), nonhome discharge disposition (p = 0.056), all-cause 90-day readmission (p = 0.226), 1-year reoperation (p = 0.597), and 1-year mortality (p = 0.861) when compared with cemented TKA. There was no significant difference in the median 1-year improvement in KOOS-pain (p = 0.370), KOOS-PS (p = 0.417), KOOS-KRQOL (p = 0.101), VR-12-PCS (p = 0.269), and VR-12-MCS (p = 0.191) between the cementless and cemented TKA cohorts. Rates of attaining MCID were similar in both cohorts for assessed PROMs (p > 0.05, each) except KOOS-KRQOL (cementless: n = 313 (96.0%) vs. cemented: n = 895 [92.7%]; p = 0.036). Cementless TKA provides similar healthcare-utilization, mortality, and 1-year PROM improvement versus cemented TKA. Cementless fixation in TKA may provide value through higher MCID improvement in quality of life. Future episode-of-care cost-analyses and longer-term survivorship investigations are warranted.

Cost-effectiveness analyses comparing cemented, cementless, hybrid and reverse hybrid fixation in total hip arthroplasty: a systematic overview and critical appraisal of the current evidence

Background: This study aims to present an overview and critical appraisal of all previous studies comparing costs and outcomes of the different modes of fixation in total hip arthroplasty (THA). A secondary aim is to provide conclusions regarding the most cost-effective mode of implant fixation per gender and age-specific population in THA, based on high quality studies.Methods: A systematic search was conducted to identify cost-effectiveness analyses (CEAs) comparing different modes of implant fixation in THA. Analysis of results was done with solely CEAs that had a high methodological quality.Results: A total of 12 relevant studies were identified and presented, of which 5 were considered to have the methodological rigor for inclusion in the analysis of results. These studies found that either cemented or hybrid fixation was the most cost-effective implant fixation mode for most age- and gender-specific subgroups.Conclusion: Currently available well performed CEAs generally support the use of cemented and hybrid fixation for all age-groups relevant for THA and both genders. However, these findings were mainly based on a single database and depended on assumptions made in the studies' methodology. Issues discussed in this paper have to be considered and future work is needed.

Femoral Stem Cementation in Hip Arthroplasty: The Know-How of a "Lost" Art

PURPOSE OF REVIEW

To describe the (1) indications, (2) preoperative precautions, and (3) stepwise technical details of modern femoral stem cemented fixation.

RECENT FINDINGS

Femoral stem cementation provides excellent implant longevity with a low periprosthetic fracture rate among patients with compromised bone quality or aberrant anatomy. Unfamiliarity with the details of modern cementation techniques among trainees who may lack frequent exposure to cementing femoral stems may preclude them from offering this viable option to suitable patients in later stages of their careers. As such, maximizing benefit from cemented femoral stem fixation among suitable candidates is contingent upon the meticulous use of modern cementation techniques. In addition to proper patient selection, modern cementation techniques emphasize the use of (1) pulsatile lavage of the femoral canal, (2) utilization of epinephrine-soaked swabs, (3) vacuum cement mixing, (4) retrograde cement introduction, (5) cement pressurization, and (6) the use of stem centralizers. Furthermore, identifying and optimizing the preoperative status of at-risk patients with pre-existing cardiopulmonary compromise, in addition to intraoperative vigilance, are essential for mitigating the risk of developing bone cement implantation syndrome. Further research is required to assess the utility of cemented femoral stem fixation among younger patients.

Periprosthetic fractures of the femur in primary total hip arthroplasty: a New Zealand Joint Registry analysis

BACKGROUND

Periprosthetic femoral fractures around total hip arthroplasty (THA) are increasing annually, and are a major cause for revision surgery in the New Zealand Joint Registry (NZJR). The aim of this study was to determine the timing and risk factors for periprosthetic femoral fractures in THA requiring revision surgery in the NZJR.

METHODS

All patients with a primary THA who sustained a periprosthetic femoral fracture requiring revision THA recorded in the NZJR were reviewed to determine age, gender, body mass index, American Society of Anesthesiologists (ASA) rating and femoral stem fixation (cemented or uncemented). Revision rates were calculated per 100 component years (cy), and risk factors determined in the first 90 days, and beyond.

RESULTS

Between 1999 and 2017, there were 713 revision THA for periprosthetic femoral fractures. Early revision THA was significantly associated with ASA score and body mass index ≥40. There was no gender difference (P = 0.274). The revision rate in uncemented femoral stems (1.12/100 cy) was significantly higher (p < 0.001) than cemented stems (0.16/100 cy). After 90 days, the revision rate was significantly higher with increasing age (P < 0.001), males (P < 0.001) and higher ASA score (P < 0.001). The difference between cemented (0.07/100 cy) and uncemented (0.05/100 cy) stems did not reach statistical significance (P = 0.108).

CONCLUSION

The rate of revision THA for periprosthetic femoral fracture is higher in uncemented femoral stems in the first 90 days, and is significantly associated with ASA score and morbid obesity. After 90 days, the rate is lower for uncemented femoral stems, but did not reach statistical significance.

The Use of Cement in Hip Arthroplasty: A Contemporary Perspective

Notable advances in hip arthroplasty implants and techniques over the past 60 years have yielded excellent survivorship of fully cemented, hybrid, and reverse hybrid total hip replacements as demonstrated in joint registries worldwide. Major advances in noncemented implants have reduced the use of cement, particularly in North America. Noncemented implants predominate today based on procedural efficiency, concern related to thromboembolic risk, and a historic belief that cement was the primary cause of osteolysis and implant loosening. With the decline of cemented techniques, press-fit fixation has become common even in osteoporotic elderly patients. Unfortunately, there is a troubling rise in intraoperative, as well as early and late postoperative periprosthetic fractures associated with the use of noncemented implants. Despite the success of noncemented fixation, an understanding of modern cement techniques and cemented implant designs is useful to mitigate the risk of periprosthetic fractures. Cemented acetabular components can be considered in elderly patients with osteoporotic or pathologic bone. Cemented stems should be considered with abnormal proximal femoral morphology, conversion of failed hip fixation, inflammatory arthritis, patient age over 75 (especially women), osteoporotic bone (Dorr C), and in the treatment of femoral neck fractures.

Cementing of the hip arthroplasty stem increases load-to-failure force: a cadaveric study

Background and purpose - To date, there is not a single clinical or mechanical study directly comparing a cemented and a cementless version of the same stem. We investigated the load-to-failure force of a cementless and a cemented version of a double tapered stem. Material and methods - 10 femurs from 5 human cadaveric specimens, mean age 74 years (68-79) were extracted. Bone mineral density (BMD) was measured using peripheral quantitative computed tomography. None of the specimens had a compromised quality (average T value 0.0, -1.0 to 1.4). Each specimen from a pair randomly received a cemented or a cementless version of the same stem. A material testing machine was used for lateral load-to-failure test of up to a maximal load of 5.0 kN. Results - Average load-to-failure of the cemented stem was 2.8 kN (2.3-3.2) and 2.2 kN (1.8-2.8) for the cementless stem (p = 0.002). The cemented version of the stem sustained a higher load than its cementless counterpart in all cases. Failure force was not statistically significantly correlated to BMD (p = 0.07). Interpretation - Implanting a cemented version of the stem increases the load-to-failure force by 25%.

Medical device surveillance with electronic health records

Post-market medical device surveillance is a challenge facing manufacturers, regulatory agencies, and health care providers. Electronic health records are valuable sources of real-world evidence for assessing device safety and tracking device-related patient outcomes over time. However, distilling this evidence remains challenging, as information is fractured across clinical notes and structured records. Modern machine learning methods for machine reading promise to unlock increasingly complex information from text, but face barriers due to their reliance on large and expensive hand-labeled training sets. To address these challenges, we developed and validated state-of-the-art deep learning methods that identify patient outcomes from clinical notes without requiring hand-labeled training data. Using hip replacements-one of the most common implantable devices-as a test case, our methods accurately extracted implant details and reports of complications and pain from electronic health records with up to 96.3% precision, 98.5% recall, and 97.4% F1, improved classification performance by 12.8-53.9% over rule-based methods, and detected over six times as many complication events compared to using structured data alone. Using these additional events to assess complication-free survivorship of different implant systems, we found significant variation between implants, including for risk of revision surgery, which could not be detected using coded data alone. Patients with revision surgeries had more hip pain mentions in the post-hip replacement, pre-revision period compared to patients with no evidence of revision surgery (mean hip pain mentions 4.97 vs. 3.23; t = 5.14; p < 0.001). Some implant models were associated with higher or lower rates of hip pain mentions. Our methods complement existing surveillance mechanisms by requiring orders of magnitude less hand-labeled training data, offering a scalable solution for national medical device surveillance using electronic health records.

Short to Midterm Follow-Up of Periprosthetic Bone Mineral Density after Total Hip Arthroplasty with the Ribbed Anatomic Stem

Background

Femoral bone remodeling around hip prosthesis after total hip arthroplasty (THA) is definite but unpredictable in time and place. This study aimed to investigate the implant-specific remodeling and periprosthetic bone mineral density (BMD) changes after implantation of the Ribbed anatomic cementless femoral stem.

Methods

After power analysis, 41 patients who had undergone primary unilateral THA with the Ribbed anatomic cementless stem were included. BMD of the seven Gruen zones was measured by dual-energy X-ray absorptiometry, and the contact, fitness, and fixation of the femoral stem and proximal femur were analyzed by X-ray. Additional clinical outcome parameters were also recorded.

Results

Compared with the contralateral unoperated side, significant reductions of BMD were detected in the distal zone (Gruen zone 4: 1.665±0.198 versus 1.568±0.242 g/cm², P=0.001) and middle distal zone (Gruen zone 5: 1.660±0.209 versus 1.608±0.215 g/cm², P=0.026) on the prosthetic side, but no significant differences in BMD were detected in other zones (Gruen zones 1, 2, 3, 6, and 7). Subgroups analyses indicated no significant correlation between periprosthetic BMD changes and clinical factors including primary disease and body mass index. Visible areas of bone ingrowth indicated solid fixation of the femoral stem and there was no case of loosening. Clinical and functional outcome scores were excellent with mean HHS of 93.13 points and mean WOMAC score of 5.20 points, and three patients described intermittent mild thigh pain at the final follow-up.

Conclusions

For the Ribbed femoral stem, the periprosthetic BMD was well maintained in the proximal femur, while periprosthetic BMD was significantly reduced in the distal and middle distal zones of the femur. Further clinical investigations are required to examine the efficacy of the Ribbed stem, particularly with regard to long-term survival. This trial is registered with ChiCTR1800017750.

Short stems in total hip replacement: evidence on primary stability according to the stem type

BACKGROUND:

As the prevalence of total hip replacement is increasing in younger patients, less invasive implants (short stems) are becoming more favourable. However, despite the advantages of these stems, clinical results with a follow-up of more than 10 years are limited to a very few stem designs. There has been an increase in publications recently - mechanical and clinical studies - concerning the primary stability of short stems. Primary stem stability is an important factor as it reflects final stem stabilisation and is related to the clinical results of the prosthesis.

METHOD:

We conducted a systematic review of the literature to retrieve evidence concerning primary implant stability in short stems - as expressed by implant micromotion and stem subsidence - according to our previously proposed short-stem classification.

RESULTS:

Mechanical in vitro studies on stem micromotion are very few and limited to type 2 "partial collum" short stems. The results are comparable to those of stems with a known long-term excellent clinical course. Clinical results concerning stem migration patterns are also limited to some of the commercially available short stems. Although comparative studies are very few, the results for most of the short stems are similar to those of standard stems.

CONCLUSION:

There are promising results concerning biomechanical studies of the initial micromotion of short stems, as well as clinical results of stem migration patterns. Long-term clinical studies are needed in order to confirm these findings. The existing literature concerns very few of the many commercially available implants.

Cemented Femoral Component Use in Hip Arthroplasty

Elderly patients undergoing both elective and nonelective hip arthroplasty contribute markedly to health care spending, and the current aging population is likely to require even more resources. Several national joint replacement registries show a lower risk of revision surgery in patients older than 75 years who received cemented femoral components compared with cementless implants for primary total hip arthroplasty. Despite a higher incidence of early periprosthetic femoral fracture, noncemented femoral components are being used with increasing frequency in elderly patients worldwide. Improvements in cementing technique and modifications to cemented stem design over several decades allow surgeons to obtain femoral component fixation in poor-quality bone with a relatively low risk of complications. Achieving durable cemented stem fixation requires the surgeon to understand the basic handling properties of cement, how to prepare the femoral bone, and differences in stem design and surface finish.

Total Hip Arthroplasty in Young Patients in The Netherlands: Trend Analysis of >19,000 Primary Hip Replacements in the Dutch Arthroplasty Register

BACKGROUND

Total hip arthroplasty (THA) is one of the most successful interventions in medical care. Because of shifting trends in THA and failure rates being higher in younger patients, we aimed to assess trends in implant fixation, bearing type, head diameter, and surgical approach in patients younger than 55 years in the Netherlands using data from the Dutch Arthroplasty Register.

METHODS

Trends in the method of implant fixation, bearing type, head diameter, and surgical approach were analyzed over year of surgery (2007-2016) and over age groups (<25, 25-29, 30-34, 35-39, 40-44, 45-49, and 50-54 years).

RESULTS

Between 2007 and 2016, a total of 19,915 primary THAs were performed in patients <55 years. Osteoarthritis was the most prevalent diagnosis (66.1%). Uncemented fixation was used in 79.5% of all performed THAs. The use of 32-mm head diameters increased (from 32.6% in 2007 to 50.1% in 2016), where an increasing trend toward the use of ceramic-on-polyethylene as most frequently used bearing type was present (from 37.5% in 2007 to 53.8% in 2016). The posterolateral surgical approach was the most frequently used approach; however, the anterior approach is used increasingly (0.1% in 2007 to 21.1% in 2016). Ceramic-on-polyethylene bearing surfaces, 32-mm head diameters, and the anterior approach were most commonly used in patients between 50 and 54 years.

CONCLUSION

There was a clear preference for uncemented fixation in young patients. In head diameter, bearing type, and surgical approach, clear trends were visible. Characteristics of THA in young patients were subject to changing perspectives.

A Wedge-Shaped Uncemented Femoral Component: Survivorship in Patients Younger Than 50 Years at a Mean Follow-Up of 22 Years

BACKGROUND

This study presents the results of the long-term survival of a wedge-shaped uncemented femoral component in a cohort of young patients with a follow-up of 20-25 years.

METHODS

In a consecutive series of 85 patients (100 hips), aged less than 50 years at the time of primary total hip arthroplasty, the long-term survival of the Cementless Spotorno femoral component was analyzed by performing a Kaplan-Meier survival analysis (95% confidence interval [CI]).

RESULTS

The mean follow-up was 22 years (range, 19.7-25.5). The clinical and radiographic outcomes were satisfactory. The overall survival rate of the femoral component was 93.4% after 23.8 years (95% CI, 85.9%-97.0%). Survival with revision for aseptic loosening as the end point was 94.4% (95% CI, 87.0%-97.6%) after 23.8 years.

CONCLUSION

This study shows an excellent long-term survival of this specific wedge-shaped uncemented femoral component after 20 to 25 years in patients younger than 50 years.