Results of the cemented Exeter femoral component in patients under the age of 40 : an update at ten to 20 years' follow-up

A comparison of cemented femoral fixation via anterior versus posterior approach total hip arthroplasty: an analysis of 60,739 total hip arthroplasties

BACKGROUND

Anterior approach total hip arthroplasty (THA) decreases the rate of dislocation but increases femoral-sided complications in the way of periprosthetic fractures and component loosening. A cemented prosthesis may reduce femoral-sided complications and improve the risk:benefit profile of anterior approach THA.

METHODS

Data from the Australian National Joint Replacement Registry were analysed for patients undergoing primary THA via the anterior or posterior approach using a cemented polished femoral stem from January 2015 to December 2021. The primary outcome measure was the cumulative percent revision (CPR) for all causes and CPR for femoral component loosening and fracture. The CPR for the primary outcome measures were compared between the anterior and posterior approach and adjusted for age, sex, ASA score, BMI and femoral head size.

RESULTS

The study included 60,739 THAs with cemented stems (10,742 anterior, 49,997 posterior). The rate of revision of the anterior versus the posterior approach did not significantly differ (HR 0.87 (95% CI, 0.74-1.03), p = 0.100). Anterior approach THA had a significantly higher rate of revision for femoral component loosening (HR 5.06 [95% CI, 3.08-8.30], p < 0.001); and a decreased rate of revision for infection (HR 0.59 [95% CI, 0.43-0.81], p = 0.001) and dislocation/instability (HR 0-3 months 0.48 [95% CI, 0.27-0.83], p = 0.008; HR >3 months 0.30 [95% CI, 0.15-0.61], p < 0.001). There was no difference in the rate of revision surgery for fracture between the 2 approaches (HR 1.01 [95% CI, 0.71-1.43]), p = 0.975).

CONCLUSIONS

There is no significant difference in overall revision rates with cemented femoral fixation performed with an anterior or posterior approach. Cemented fixation performed with the anterior approach partly mitigates femoral complications with no difference in the revision rate for fracture but an increased rate of femoral component loosening.

Outcomes of Exeter cemented total hip arthroplasty in a county hospital: survivorship of eight hundred and ninety four hips with a minimum ten-year follow up

PURPOSE

A total of 894 hips were evaluated to describe the survivorship of Exeter cemented femoral stems and report the outcomes and complications of our 'Exeter- era', and there is no study from Central or Eastern Europe demonstrating similar results.

METHODS

Between January 2000 and December 2009, a total of 894 hips were included who underwent Exeter universal and V40 femoral stems with a mean follow up of 13 years. Cemented Exeter low profile polyethylene cups were used in 889 patients (99.4%) cups. Harris hip score (HHS) was used and statistical outcome measures were calculated with revision as an endpoint for aseptic loosening of the stem, aseptic loosening of any component, all-cause revision of the stem, and all-cause revision of the hip.

RESULTS

A total of 103 patients died and 129 (14.4%) operated hips were lost to follow-up before ten years. Out of the 662, ten stems (1.5%) were revised for aseptic loosening. Aseptic loosening of any component was the reason for revision in 43 cases (6.5%), consisting of 40 cup revisions and ten stem exchanges. Periprosthetic fracture occurred in 17 cases (1.9%) Periprosthetic joint infection occurred in 18 cases (2.01%). Three cups were exchanged for recurrent dislocation, and two stems had broken.

CONCLUSION

Exeter hip system has provided reproducible results across different centres worldwide, as it did in our series. Thorough surgical and cementing technique is of utmost importance for achieving these results. The cup is the weak point of the system and use of a hybrid system is worth considering.

The exeter cemented stem provides outstanding long-term fixation and bone load at 15 years follow-up: A systematic review and meta-analysis

PURPOSE

Since its introduction in 1988, the double-tapered polished Exeter cemented stem has been widely adopted in primary total hip arthroplasty (THA). Despite the results coming from the arthroplasty registries have proven great survivorship, the aim of this study was to dig deeper and describe the modes of failure of the Exeter stem at 15 years follow-up while reporting the clinical and radiographic outcomes.

METHODS

A search of PubMed, MEDLINE, and Embase was performed using the Preferred Reporting Items for Systematic Review and Meta-Analyses since inception of database to January 2022. A meta-analysis was performed on stem's failure rates and clinical outcomes using random effects models. Publication bias was assessed with funnel plots.

RESULTS

Overall, ten studies met the inclusion criteria with 2167 hips at mean 14.8 ± 4.1 years follow-up. The meta-effect estimate for revision rate for stem-related reasons was 3.8% (CI 95% 2.1-5.6, p < 0.01). The meta-effect for revision rate for stem aseptic loosening (AL) was 0.22% (CI 95% 0-0.4, p = 0.048) and for periprosthetic fracture was 0.6% (CI95% 0.3-0.9, p < 0.001). The meta effect estimate for Oxford Hip Score (OHS) at final follow-up was 32.4 (moderate; CI 95% 23.2-41.6, p <0.001) with and heterogeneity among the studies of I² 0%. Radiolucent lines were reported in 5.5% of cases, with 1.0% of cases (21 hips) reported to be progressive.

CONCLUSION

Current evidence suggests that the Exeter cemented stem not only has proven long-term outstanding reliability with a revision rate of 3.8%, but also incredibly low revision rates for AL (0.22%) and periprosthetic fracture (0.6%). It is suitable for a variety of indications, and the consistent radiological appearances indicate durable fixation and load transmission while being associated with a remarkably low stem-related complication rate.

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.

Minimum 10-Year Follow-Up of Total Hip Arthroplasty With a Collarless Triple-Tapered Polished Cemented Stem With Line-to-Line Implantation Using a Direct Anterior Approach

BACKGROUND

The Trilliance stem (B. Braun-Aesculap, Tuttlingen, Germany), a novel collarless triple-tapered polished stem, was introduced in 2009. The aim of this study is to evaluate the long-term clinical and radiological results of the Trilliance stem with line-to-line implantation in primary total hip arthroplasty using a direct anterior approach.

METHODS

A consecutive retrospective series of 130 patients (151 hips) who underwent total hip arthroplasty between February 2009 and August 2011 were evaluated for a minimum of 10 years. Of these, 87.4% had a diagnosis of secondary osteoarthritis based on developmental hip dysplasia. Clinical and radiological results, complications were evaluated and survival analysis was performed.

RESULTS

The mean follow-up was 10.7 years (range, 10.0-12.1). Thirteen hips (13 patients, 6.8%) were lost to follow-up. Adequate cementation (Barrack grade A) was achieved in 136 hips (93.8%) 1 week post-operatively. Nearly all (144 hips, 99.3%) had been inserted within the range of 3°. No significant differences were identified between high- (≥30 procedures/year) and low- (<30 procedures/year) volume surgeons. The Kaplan-Meier survival analysis with revision of the femoral component for aseptic loosening, revision of the femoral component for any reason and revision of either component for any reason as the end points, cumulative survivorship was 100.0%, 97.6% (95% confidence interval (CI) 95.4-100.0) and 96.5% (95% CI 93.8-99.3) at 10 years, respectively.

CONCLUSION

The Trilliance stem with line-to-line implantation using a direct anterior approach has an excellent clinical and radiological outcome at a minimum of 10 years' follow-up.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

Clinical Outcomes and Survivorship of Hybrid Total Hip Arthroplasty Performed Through the Anterior Approach

INTRODUCTION

There is growing evidence that cemented femoral stems have lower complication rates in the elderly due to lower rates of periprosthetic fracture. The main objective of this study was to analyze the survival rate of a hybrid total hip arthroplasty (THA) construct utilizing a taper-slip femoral stem implanted through the anterior approach (AA). Secondary outcome measures were the complication rate, the rate of aseptic loosening, coronal plane alignment of the stem, and the grade of the cement mantle.

METHODS

Patients who underwent AA hybrid THA from 2013 to 2020 were included. Indications for a cemented stem were age over 70 or patients with poor bone quality. Descriptive statistics were calculated for patient characteristics. Serial radiographs were reviewed for component alignment and for evidence of implant loosening. The survival of the femoral stem was recorded, with failure defined as femoral stem revision for any reason or radiographic evidence of implant loosening.

RESULTS

A total of 473 hybrid THA in 426 patients were identified, with a mean age of 76 years. Mean follow-up was 38 months. Femoral stem survival was 99.2%. There were no cases of aseptic loosening of the femoral component. Mean coronal stem alignment was 0.2 degrees varus, and all were within 5 degrees of neutral. Cement mantle grade was either A or B in 94% of cases.

CONCLUSION

AA hybrid THA is an excellent option in elderly patients, or patients with poor bone quality, with a femoral stem survival rate of 99.2% and a 0% rate of aseptic loosening.

Collarless Taper Slip and Collared Composite Beam Stems Differ in Failure Modes and Reoperation Rates

BACKGROUND

Cemented femoral components are used in older patients based on lower risk of periprosthetic fracture and implant loosening. This study reports the survivorship free of periprosthetic femoral fracture (PPFX), femoral loosening, all-cause revision, and reoperation between 2 philosophies of cemented stems.

METHODS

In total, 1,306 primary hybrid total hip arthroplasties were performed for osteoarthritis between 2000 and 2018 in a retrospective single center study. Cemented stems included 798 EON composite beam (CB) and 508 Exeter collarless taper slip (CTS) stems. Mean age was 77 years. An inverse treated probability weighted model was utilized to control for risk factors including age, gender, body mass index, year, and surgeon.

RESULTS

There was no difference in risk of PPFX at 10 years (CTS 9% vs CB 5%; hazard ratio [HR] 1.4, P = .47). There was an increased risk of intraoperative fractures requiring fixation in the CB cohort (7/798 [5 calcar, 2 greater trochanter] vs 0/508, P < .001), while there was an increased risk of Vancouver B₂ PPFX in the CTS cohort (7/508 vs 0/798; P < 001). There was a higher risk of femoral loosening in the CB cohort (6/798 vs 0/508; P < .0001). Higher survivorship free of revision (98% vs 91%; HR 4, P = .001) and free of reoperation (96% vs 88%; HR 2.5, P = .002) was seen at 10 years in the CB cohort.

CONCLUSION

The risk of PPFX requiring implant revision was increased in the CTS cohort, while there was an increased risk of femoral component loosening and intraoperative fractures seen in the CB cohort. Surgeons should be aware of the different failure modes when choosing implant design for their patient.

Revisiting Cemented Femoral Fixation in Hip Arthroplasty

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The primary means of femoral fixation in North America is cementless, and its use is increasing worldwide, despite registry data and recent studies showing a higher risk of periprosthetic fracture and early revision in elderly patients managed with such fixation than in those who have cemented femoral fixation.

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Cemented femoral stems have excellent long-term outcomes and a continued role, particularly in elderly patients.

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Contrary to historical concerns, recent studies have not shown an increased risk of death with cemented femoral fixation.

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The choice of femoral fixation method should be determined by the patient's age, comorbidities, and bone quality.

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We recommend considering cemented femoral fixation in patients who are >70 years old (particularly women), in those with Dorr type-C bone or a history of osteoporosis or fragility fractures, or when intraoperative broach stability cannot be obtained.

High rates of implant fracture of a generic polished tapered femoral stem

OBJECTIVES

Cemented polished tapered stems have demonstrated excellent long-term outcomes. Based on this concept, many generic tapered stems have been released into the market. The aim of this study was to evaluate implant-related complications of 1 specific stem design.

METHODS

Between 2010 and 2017, 315 total hip replacements were performed using a Fortress stem (Biotechni, La Ciotat, France). Patient records and radiology were retrospectively reviewed for implant-related complications. A failure analysis was performed on the failed Fortress stems in order to determine the cause of premature failure.

RESULTS

7 (2.2%) patients sustained a fracture of the neck of the implant after a mean of 5 years (range 50-81 months). All fractures were atraumatic, originating at the introducer inlet of the stem. All fractured occurred in obese patients (BMI >33 kg/m²) with a small sized prosthesis. Of these, there were 5 135° and 2 125° stems. Fracture risk was 23% (7/30) for patients with a small sized stem and a BMI >30 kg/m². All cases were revised using a cement-in-cement technique or a cementless modular revision stem. Failure analysis on the retrieved stems revealed a stress riser at the bottom of the introducer inlet.

CONCLUSIONS

An alarmingly high rate of early implant fractures was seen using this specific type of cemented stem, particularly when using smaller implant sizes in obese patients. Although based on a proven design, a specific modification led to a stress riser in the neck area, which resulted in a high incidence of implant failure. This series underlines the importance of a stepwise introduction into the market of new orthopaedic devices even when based on established concepts. Generic stems may not behave as the original stem upon which it was designed.

Midterm Results of Primary Exeter Cemented Stem in a Select Patient Population

BACKGROUND

Most North American surgeons predominantly use uncemented stems in primary total hip arthroplasties (THAs) and reserve cemented stems for selected older patients and those with poor bone quality. However, data on this "selective use" strategy for cemented stems in the population at risk for periprosthetic fracture and implant loosening are limited. The purpose of this study was to describe implant survivorship, complications, and radiographic results of a specific collarless, polished, tapered cemented stem (Exeter; Stryker) used selectively in a predominantly elderly population undergoing primary THA.

METHODS

We identified 386 patients who underwent a total of 423 primary THAs with selectively utilized Exeter stems for the treatment of osteoarthritis between 2006 and 2017. In the same time period, 11,010 primary THAs were performed with uncemented stems and 961 with non-Exeter cemented stems. The mean patient age was 77 years, 71% were female, and the mean body mass index was 29 kg/m2. Competing risk analysis accounting for death was utilized to determine cumulative incidences of revision and reoperation. The mean follow-up was 5 years (range, 2 to 12 years).

RESULTS

The 10-year cumulative incidence of any femoral component revision in this patient cohort was 4%, with 10 stems revised at the time of the latest follow-up. There were no intraoperative femoral fractures. The indications for revision were postoperative periprosthetic femoral fracture (n = 6), dislocation (n = 3), and infection (n = 1). There were no revisions for femoral loosening. The 10-year cumulative incidence of reoperation was 10%. The 10-year cumulative incidence of Vancouver B periprosthetic femoral fracture was 2%. Radiographically, there were no cases of aseptic loosening or osteolysis. There was a significant improvement in median Harris hip score, from 53 preoperatively to 92 at a mean follow-up of 5 years (p < 0.001).

CONCLUSIONS

The strategy of selectively utilizing a collarless, polished, tapered cemented stem produced a low (4%) cumulative incidence of stem revision at 10 years postoperatively and resulted in no cases of aseptic loosening. The use of the Exeter stem did not eliminate postoperative femoral fractures in this predominantly elderly, female patient population.

LEVEL OF EVIDENCE

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

The Effects of Rasp Oversize on the Clinical and Radiographic Outcomes of Total Hip Arthroplasty With a Collared Satin-Finished Composite Beam Cemented Stem

BACKGROUND

This study aimed to compare the clinical and radiographic outcomes of using two different oversized rasps in total hip arthroplasty (THA) with a composite beam cemented stem (DCM-J).

METHODS

A consecutive series of 105 hips underwent hybrid THA using the DCM-J stem between 2006 and 2010. Among the patients with a minimum 10-year follow-up, a 1.5-mm oversized rasp was used in 38 hips (group S), whereas a 0.5-mm oversized rasp was used in 36 hips (group M). The Japanese Orthopedic Association hip score and radiographic findings were evaluated, including cement mantle thickness, stress shielding, and cortical hypertrophy.

RESULTS

The Japanese Orthopedic Association hip score was significantly improved postoperatively with 100% of the implant survival rate in both groups when septic loosening was excluded. Radiographic assessment performed immediately postoperatively revealed that the cement mantle thickness was significantly larger in group M than group S in Gruen zone 1 but did not differ between groups in zones 2-7. Stress shielding was significantly more frequent in group M than group S at 2 years (P = .011), 5 years (P = .012), and ≥10 years postoperatively (P = .038). Cortical hypertrophy appeared in a time-dependent manner; however, the prevalence did not significantly differ between groups at final follow-up at a mean of 11.7 years (range 10-14 years) postoperatively.

CONCLUSIONS

The DCM-J stem achieved good clinical results in both groups. Stress shielding was significantly more frequent in THA using the 0.5-mm rasp than the 1.5-mm rasp, indicating that sufficient cement mantle room should be prepared for the cemented stem.

Temporal subsidence patterns of cemented polished taper-slip stems: a systematic review

The literature was reviewed to establish the levels of stem subsidence for both double and triple-tapered implants in order to determine whether there were any differences in subsidence levels with regard to the methods of measurement, the magnitude and rate of subsidence and clinical outcomes.

All studies reporting subsidence of polished taper-slip stems were identified. Patient demographics, implant design, radiological findings, details of surgical technique, methods of measurement and levels of subsidence were collected to investigate which factors were related to increased subsidence.

Following application of inclusion and exclusion criteria, 28 papers of relevance were identified. The studies initially recruited 3090 hips with 2099 being available for radiological analysis at final follow-up. Patient age averaged 68 years (42–70), 60.4% were female and the average body mass index (BMI) was 27.4 kg/m² (24.1–29.2).

Mean subsidence at one, two, five and 10 years was 0.97 mm, 1.07 mm, 1.47 mm and 1.61 mm respectively. Although double-tapered stems subsided more than triple-tapered stems at all time points this was not statistically significant (p > 0.05), nor was the method of measurement used (p > 0.05).

We report the levels of subsidence at which clinical outcomes and survivorship remain excellent, but based on the literature it was not possible to determine a threshold of subsidence beyond which failure was more likely.

There were relatively few studies of triple-tapered stems, but given that there were no statistically significant differences, the levels presented in this review can be applied to both double and triple-tapered designs.

Cite this article: EFORT Open Rev 2021;6:331-342. DOI: 10.1302/2058-5241.6.200086

Sport after total hip arthroplasty: undoubted progress but still some unknowns

In this review, we discuss the evidence for patients returning to sport after hip arthroplasty. This includes the choices regarding level of sporting activity and revision or complications, the type of implant, fixation and techniques of implantation, and how these choices relate to health economics. It is apparent that despite its success over six decades, hip arthroplasty has now evolved to accommodate and support ever-increasing patient demands and may therefore face new challenges. Cite this article: Bone Joint J 2020;102-B(6):661-663.

Cemented or uncemented acetabular fixation in combination with the Exeter Universal cemented stem

AIMS

To compare long-term survival of all-cemented and hybrid total hip arthroplasty (THA) using the Exeter Universal stem.

METHODS

Details of 1,086 THAs performed between 1999 and 2005 using the Exeter stem and either a cemented (632) or uncemented acetabular component (454) were collected from local records and the New Zealand Joint Registry. A competing risks regression survival analysis was performed with death as the competing risk with adjustments made for age, sex, approach, and bearing.

RESULTS

There were 61 revisions (9.7%; 0.82 revisions/100 observed component years, (OCYs)) in the all-cemented group and 18 (4.0%; 0.30/100 OCYs) in the hybrid group. The cumulative incidence of revision at 18 years was 12.1% for cemented and 5.2% for hybrids. There was a significantly greater risk of revision for all-cemented compared with hybrids (unadjusted sub-hazard ratio (SHR) 2.44; p = 0.001), and of revision for loosening, wear, or osteolysis (unadjusted SHR 3.77; p < 0.001). After adjustment, the increased risk of all-cause revision did not reach significance at age 70 years and above. The advantage for revision for loosening, wear, and osteolysis remained at all ages.

CONCLUSION

This study supports the use of uncemented acetabular fixation when used in combination with the Exeter stem with improved survivorship for revision for aseptic loosening, wear, and osteolysis at all ages and for all-cause revision in patients less than 70 years. Cite this article: Bone Joint J 2020;102-B(4):414-422.

Long-Term Survival of the Cemented Exeter Universal Stem in Patients 50 Years and Younger: An Update on 130 Hips

BACKGROUND

There is variable evidence regarding survivorship beyond 20 years of total hip arthroplasties in young patients. We report the long-term results of the Exeter cemented hip system in patients ≤50 years at minimum of 20 years.

METHODS

Clinical and radiological outcomes of 130 consecutive total hip arthroplasties in 107 patients aged 50 years or younger at primary operation were reviewed; 77% had a diagnosis other than osteoarthritis. All patients were followed at 5-year intervals, no patients were lost to follow-up, and the status of every implant is known.

RESULTS

Mean age at surgery was 41.8 (17-50) years. Mean follow-up was 22.0 (20.0-26.1) years. There were 79 hips surviving, 14 hips (11 patients) deceased, and 37 hips revised. Reasons for revision: 29 hips for aseptic cup loosening (26 stems revised using cement-in-cement, three left in-situ); three stems for femoral osteolysis, two related to acetabular polyethylene wear (14.1 and 17.0 years), one with Gaucher's disease (21.1 years); one broken stem (12.9 years); one cup for instability (4.3 years-stem revised using cement-in-cement); and two hips with infection (8.5 and 23.8 years). There were no cases of aseptic loosening of the Exeter stem. There were no radiologically loose stems although eight patients had radiological evidence of loosening of the cemented cup. Survivorship at 22 years was 74.9% for revision for all causes and 96.3% for revision of the stem for aseptic loosening or lysis.

CONCLUSION

The Exeter cemented stem has excellent survivorship at minimum 20 years in young patients. Acetabular component survivorship was less favorable, but the advent of highly cross-linked polyethylene may improve this in the long term.

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.

Hybrid Fixation for Total Hip Arthroplasty Showed Improved Survival Over Cemented and Uncemented Fixation: A Single-Center Survival Analysis of 2156 Hips at 12-18 Years

BACKGROUND

Despite increased use of uncemented and hybrid fixation, there is little evidence of their superiority over cemented implants. The aim of this study is to compare the long-term survivorship of cemented, hybrid and uncemented total hip arthroplasty (THA) at varying ages.

METHODS

A total of 2156 hips (1315 cemented, 324 uncemented, and 517 hybrid) were performed in a single center between 1999 and 2005 with follow-up through to 2017. Registry and local databases were used to determine revision rates and cause. Unadjusted and adjusted competing risk survival analysis was performed.

RESULTS

The cumulative incidence of all-cause revision at 18 years was cemented 10.9%, uncemented 8.9%, and hybrid 6.5%. Cemented fixation had a statistically significant higher risk of all-cause revision than hybrid in the adjusted model for all ages to 65 years (subhazard ratios [SHRs], 2.28-4.67) and a higher risk of revision for loosening, wear, or osteolysis at all ages (SHRs, 3.25-6.07). Uncemented fixation showed no advantage over hybrid fixation at any age, but did show advantages over cemented at younger ages (≤60 years) for all-cause revision (SHRs, 2.3-4.3).

CONCLUSION

Hybrid fixation with conventional polyethylene shows an advantage over cemented hips at all ages. Uncemented THA showed improved survival over cemented only at younger ages and no advantage over hybrid THA.

Is cemented revision total hip arthroplasty a reasonable treatment option in an elderly population?

Revision THA is increasingly performed especially in the elderly population. The surgeon’s challenge is to provide a solution that supports immediate full weight-bearing, despite poor bone quality. Shape-closed revision stems facilitate that by combining cement fixation with additional press-fit anchoring. The design tolerates varying cement mantle thickness and inconsistent cancellous bone lining of the femoral canal. Following that philosophy, we present our mid-term results using a long version of a cemented Charnley- Kerboull type stem. From 2010 to 2017, 38 long Charnley-Kerboull revision stems (Centris^®, Mathys European Orthopaedics, Bettlach, Switzerland) were implanted and followed prospectively. Surgery was performed via a Hardinge approach in supine position with a third generation cementing technique. Patients were mobilized using full-weight bearing as early as possible. Survival was determined for stem revision for aseptic loosening and stem and/or cup revision for any reason. 20 stems had a minimum follow-up (f/u) of 2 years and were included for further radiological analysis. Detailed subsidence analysis as an early predictor for later aseptic loosening was performed using EBRA-FCA software. Further, the presence of osteolysis and cement debonding was evaluated. Mean follow- up was 4 years. No patient was lost to f/u.18 died of causes unrelated to THA. Stem survival was 100%. Survival for any re-operation was 82.2% (two early infections, one soft-tissue debridement, one cup exchange for recurrent dislocations). None of the cases revised for septic loosening showed signs of persistent infection at final f/u. EBRA-FCA revealed two oligosymptomatic cases of subsidence of 5mm and 6mm over a course of 2 and 12 months, respectively, with stable implants thereafter. Neither required revision. There was no development of osteolysis or debonding. The stem provides a reliable early fullweight bearing solution for revision THA with excellent mid-term survival in an elderly population. Even in two cases where subsidence was present, mobility was not impaired and re-revision could be avoided.

Five-year prospective subsidence analysis of 100 cemented polished straight stems: A concise clinical and radiological follow-up observation

Early subsidence (>1.5mm) has been shown to be an indicator for later aseptic loosening of cemented hip stems. For the cemented twinSys^® stem we published excellent short-term results at 2 years. Midterm data for this stem are available from national registers (NZL, NL), however in all of these sources, clinical and radiological results are missing. Aim of our study was to analyse mid-term survival and radiological changes around the cemented twinSys^® stem with special emphasis on subsidence using EBRA-FCA. We conducted a prospective clinical and radiological 5- year follow-up study of 100 consecutive hybrid total hip arthroplasties (THA) using a polished, cemented collarless straight stem (twinSys^®, Mathys AG^® Bettlach, Switzerland) with a cementless monobloc pressfit cup (RM pressfit^®, Mathys AG^® Bettlach, Switzerland). Median age at surgery was 79 (69 to 93) years. No patient was lost to follow-up. Survival rates were calculated using the Kaplan-Meier method. Clinical (Harris Hip Score [HHS]) and radiological (cementing quality, alignment, osteolysis, debonding and cortical atrophy) outcomes and an in-depth subsidence analysis using EBRA-FCA were performed. 22 patients died in the course of follow-up unrelated to surgery, 21 stems had an incomplete radiological follow-up. 2 stems were revised, both due to an infection. The survival rate for the stem at 5 years was 98.0% (95% CI 95.3-100%). The survival rate of the stem for revision due to aseptic loosening at 5 years was 100%. The HHS improved from 53 (14-86) points preoperatively to 90 (49-100) points 5 years after surgery. Osteolysis was found in 2 stems without clinical symptoms. In 49 out of 55 patients with a complete radiological follow- up, the EBRA-FCA analysis was possible and showed an average subsidence of 0.66 (95% CI 0.46 to 0.86) mm 5 years after surgery. 10 patients showed a subsidence >1 mm, 5 of which bigger than 1.5 mm. Subsidence was independent from radiological changes and cementing quality. The cemented twinSys^® stem showed excellent clinical and radiological mid-term results at five years' follow-up and seems to be a reliable implant.