The C-stem in clinical practice: fifteen-year follow-up of a triple tapered polished cemented stem

Increased risk of periprosthetic fracture associated with decreased aseptic loosening in C-stem compared with the Charnley Elite Plus in primary total hip arthroplasty: a minimum 10-year follow-up study

BACKGROUND

The Charnley stem design has evolved, with notable modifications from the 6th generation (Elite Plus) to the 7th generation (C-stem), potentially affecting load transmission and clinical outcomes. This study aimed to compare the clinical, radiological, and survival outcomes between the Elite Plus and C-stem.

METHODS

A retrospective review was conducted on 131 primary total hip arthroplasties in 115 patients. A minimum 10-year follow-up was completed for 89 hips (78 patients) with the Elite Plus and 42 hips (37 patients) with the C-stem, with mean follow-ups of 15.8 and 11.7 years, respectively.

RESULTS

The surgical procedures were hybrid arthroplasty with lateral and posterior approach for the Elite Plus group and cement arthroplasty with anterior and lateral approach for the C-stem group. In the Elite Plus group, five patients experienced dislocations and three developed aseptic loosening (AL); in the C-stem group, three cases of periprosthetic fracture (PPF) occurred. Four cases in the Elite Plus and two cases in the C-stem group required revision arthroplasty. The reasons for revision surgery were AL of the acetabular component in two cases and femoral AL in two cases in the Elite Plus group and PPF in two cases in the C-stem group. Radiolucent lines were significantly more frequent with the Elite Plus (33.7%) than with the C-stem (11.9%). After excluding three patients with extreme subsidence (≥ 3 mm) in the Elite Plus group, the average stem subsidence was found to be significantly larger with the C-stem (0.88 mm) than with the Elite Plus (0.17 mm) (p < 0.001, Mann-Whitney U test). With revision surgery due to any reason as the endpoint, the 10-year survival rates were 96.6% for the Elite Plus and 95.2% for the C-stem, showing no significant difference. However, survival rates differed significantly with PPF as the endpoint (100% for the Elite Plus vs. 92.9% for the C-stem, p = 0.01).

CONCLUSIONS

Both stems achieved satisfactory 10-year outcomes. The Elite Plus stem showed more frequent loosening and radiolucent lines, whereas the C-stem demonstrated a stable cement-bone interface but had several PPF cases. Design differences likely contributed to these variations in outcomes.

The 'Japanese paradox' of total hip arthroplasty: where are we going?

INTRODUCTION

There is a worldwide trend toward 'revisiting' cemented total hip arthroplasty (THA). In Japan, however, cemented THAs accounts for 11%, and the percentage of cemented hemiarthroplasty is estimated to be less than 10%. This review was designed to reconsider the option of cemented THA and to encourage policy changes in Japan to support the best possible care for patients.

AREA COVERED

In this article, we reviewed the history of THA and the current situations of the world, based on past reports and nationwide registries. Merits and demerits of cemented THA were evaluated from various perspectives.

EXPERT OPINION

Cemented THA had great advantages, including establishment of the acetabular cup, diversity of the femoral stem, antibiotic-loaded acrylic cement, revision, low incidence of periprosthetic fracture, and hemiarthroplasty. In patients older than 75 years of age, cemented THA resulted in the lowest risk of revision. Guidelines for femoral neck fracture recommended the use of cemented hemiarthroplasty in many countries because of low incidence of periprosthetic fracture. Numerous contradictions regarding implant price and cost of operations have also been noted in Japan. For the patients, we need to rethink what is truth and what is fiction.

Cemented femoral stem design and postoperative periprosthetic fracture risk following total hip arthroplasty

Polished taper-slip (PTS) cemented stems have an excellent clinical track record and are the most common stem type used in primary total hip arthroplasty (THA) in the UK. Due to low rates of aseptic loosening, they have largely replaced more traditional composite beam (CB) cemented stems. However, there is now emerging evidence from multiple joint registries that PTS stems are associated with higher rates of postoperative periprosthetic femoral fracture (PFF) compared to their CB stem counterparts. The risk of both intraoperative and postoperative PFF remains greater with uncemented stems compared to either of these cemented stem subtypes. PFF continues to be a devastating complication following primary THA and is associated with high complication and mortality rates. Recent efforts have focused on identifying implant-related risk factors for PFF in order to guide preventative strategies, and therefore the purpose of this article is to present the current evidence on the effect of cemented femoral stem design on the risk of PFF.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Survivorship of the C-Stem total hip replacement using the "French Paradox" technique

BACKGROUND

This study evaluates the survivorship of the C-Stem total hip replacement, using the "French Paradox" method, at medium-term follow-up.

METHODS

321 cemented total hip replacements in 307 patients were performed, using the canal-filling technique for the femoral stem. Survival analysis was performed for all-cause revision. The secondary outcome was aseptic loosening of the stem.

RESULTS

Revision rate for all reasons was 2%. Overall ten-year survival was 95%. There were no revisions for femoral stem aseptic loosening.

CONCLUSION

This is a unique study demonstrating successful outcomes of total hip replacement using the "French Paradox" technique with a triple-tapered stem.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

Aims

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

Methods

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

Results

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

Conclusion

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

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

Minimum ten-year outcome of a triple-tapered femoral stem implanted with line-to-line cementing technique

Background

A triple-tapered polished femoral stem was implanted with line-to-line cementing technique. The purpose of this study was to determine the survivorship, loosening rate, stem subsidence, radiologic changes and clinical outcomes in the minimum 10-year follow-up.

Methods

This was a retrospective study done in three institutes. Finally, 118 hips in 97 patients could be followed-up at the mean follow-up period of 126.3 months. The survivorship, radiological and clinical outcomes were investigated.

Results

Radiologically, 107 hips (90.7%) were categorized to Barrack cementing grade A, and 108 stems (91.5%) were inserted in neutral position. All hips were not loose and were not revised due to any reason. Survival with revision for any reason as the endpoint was 100% after 10 years. At the last follow-up, the mean subsidence was 0.43 mm, and the subsidence was less than 1 mm in 110 hips (93.2%).

JOA hip score improved from 42.7 ± 8.9 points preoperatively to 92.8 ± 6.8 points at the last follow-up. No patient complained thigh pain.

Conclusions

Line-to-line cementing technique with use of a triple-tapered polished stem was effective to achieve good cementation quality and centralization of the stem. The subsidence was small, and the minimum 10-year results were excellent without any failures related to the stem.

Trial registration

Retrospectively registered.

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

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem

BACKGROUND

This study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years.

METHODS

We conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael's Hip Score.

RESULTS

Forty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael's Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening.

CONCLUSION

This triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.

Postoperative migration of the anatomical and functional anteversion angle following total hip arthroplasty with a well-fixed cemented femoral component with line-to-line implantation

INTRODUCTION

Little is known about the association between well-fixed polished tapered cemented stems (PTCS) implanted by the line-to-line technique and changes of stem migration, or the change of functional anteversion of the femur after total hip arthroplasty (THA).

MATERIALS AND METHODS

This retrospective study included 422 two-stage bilateral primary THAs performed using PTCS implanted by the line-to-line technique. CT scans were made on both the target side (first postoperative CT) and on the contralateral side (second postoperative CT) 1 week postoperatively. The mean follow-up was 7.8 months. CT data for each scan were transferred to 3D template software (Zed hip, Lexi, Japan). The postoperative changes of anatomical stem anteversion (ASA), functional femoral anteversion (FFA), and stem subsidence were evaluated.

RESULTS

A total of 20 THAs with CT scans were available on 3D template software. The ASA and the FFA had migrated - 0.68° ± 0.62° and - 5.5° ± 9.7°, respectively, over the follow-up period. A significant positive correlation was observed between the change of subsidence and ASA (r² = 0.34, p = 0.007), between the FFA on the second postoperative CT and ASA on the first postoperative CT (r² = 0.26, p = 0.02) and between the FFA on the second postoperative CT and FFA on the first postoperative CT (r² = 0.52, p = 0.0003).

CONCLUSION

This study indicates that the change in axial rotation of a PTCS implanted by the line-to-line technique was less than that reported by other studies and the preoperative external rotation contracture was substantially improved after THA.

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.

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

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

Radiographic evaluation of cementation technique using polished, conical, triple-tapered femoral stem in hip arthroplasty

Objective

To radiographically evaluate the quality of cementation and implantation technique using a polished, triple-tapered femoral stem in total hip arthroplasty (THA).

Method

Retrospective study with radiographic evaluation of 86 hips in 83 patients who underwent to primary THA with the triple-tapered cemented femoral stem C-Stem (DePuy Orthopedics, Warsaw, Indiana). Cases with at least one-year of follow-up were included, and data related to preoperative, immediate postoperative, and late postoperative radiographic evolution were recorded. This study analyzed, among others, the proximal femoral anatomy, the quality of cementation as described by Barrack, and the implant positioning. Cementation was also evaluated and quantified in the Gruen zones with one-year of follow-up.

Results

The mean age was 62.85 years. Proximal femoral anatomical conformation was Dorr type A in 34 (39.53%) cases, type B in 52 (60.46%), and no type C cases were found. Five (5.81%) cases were defined as type A by Barrack's cementation classification system, 46 (56.49%) type B, 27 (31.40%) type C, and eight (9.30%) type D. The greatest cement mantle thickness was observed in zones four (15.53 mm) and 11 (15.64 mm), and the smallest in zone nine (3.51 mm). Positioning in varus was observed in eight (9.3%) cases, valgus in 25 (29%), forward deviation in two (5%), and backward deviation in 55 (63.95%).

Conclusions

The C-Stem femoral system presented satisfactory results related to cementation pattern, positioning, osteolysis, and stress shielding with regard to literature referring to double-tapered or triple-tapered models, demonstrating to be a safe method, with a predictable and reliable cementing pattern.

The Synergy cementless femoral stem in primary total hip arthroplasty at a minimum follow-up of 15 years

AIMS

We report on the outcome of the Synergy cementless femoral stem with a minimum follow-up of 15 years (15 to 17).

PATIENTS AND METHODS

A retrospective review was undertaken of a consecutive series of 112 routine primary cementless total hip arthroplasties (THAs) in 102 patients (112 hips). There were 60 female and 42 male patients with a mean age of 61 years (18 to 82) at the time of surgery. A total of 78 hips in the 69 patients remain in situ; nine hips in eight patients died before 15 years, and 16 hips in 16 patients were revised. Clinical outcome scores and radiographs were available for 94 hips in 85 patients.

RESULTS

In all, four stems were revised. One stem was revised for aseptic loosening; two stems because of deep infection; and one because of periprosthetic femoral fracture. There was a significant improvement in all components of the Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up (total: p < 0.001, pain: p < 0.001, stiffness: p < 0.001, function: p < 0.001). The mean Harris Hip Scores improved from 47 points (27 to 59) pre-operatively to 89 points (65 to 100) at the latest follow-up (p < 0.001). Kaplan-Meier survivorship, with stem revision for aseptic loosening as the endpoint, was 98.9% at 15 years (95% confidence interval (CI) 96.9 to 100, number at risk at 15 years: 90) and with stem revision for any reason was 95.7% (95% CI 91.7 to 99.8, number at risk at 15 years: 90).

CONCLUSION

The Synergy cementless femoral stem demonstrates excellent survivorship and functional outcomes at 15 years. Cite this article: Bone Joint J 2017;99-B:29-36.

Implant survival of the most common cemented total hip devices from the Nordic Arthroplasty Register Association database

Background and purpose - According to previous Nordic Arthroplasty Register Association (NARA) data, the 10-year implant survival of cemented total hip arthroplasties (THAs) is 94% in patients aged 65-74 and 96% in patients aged 75 or more. Here we report a brand-level comparison of cemented THA based on the NARA database, which has not been done previously. Patients and methods - We determined the rate of implant survival of the 9 most common cemented THAs in the NARA database. We used Kaplan-Meier analysis with 95% CI to study implant survival at 10 and 15 years, and Cox multiple regression to assess survival and hazard ratios (HRs), with revision for any reason as endpoint and with adjustment for age, sex, diagnosis, and femoral head material. Results - Spectron EF THA (89.9% (CI: 89.3-90.5)) and Elite THA (89.8% (CI: 89.0-90.6)) had the lowest 10-year survivorship. Lubinus (95.7% survival, CI: 95.5-95.9), MS 30 (96.6%, CI: 95.8-97.4), and C-stem THA (95.8%, CI: 94.8-96.8) had a 10-year survivorship of at least 95%. Lubinus (revision risk (RR) = 0.77, CI: 0.73-0.81), Müller (RR =0.83, CI: 0.70-0.99), MS-30 (RR =0.73, CI: 0.63-0.86), C-stem (RR =0.70, CI: 0.55-0.90), and Exeter Duration THA (RR =0.84, CI: 0.77-0.90) had a lower risk of revision than Charnley THA, the reference implant. Interpretation - The Spectron EF THA and the Elite THA had a lower implant survival than the Charnley, Exeter, and Lubinus THAs. Implant survival of the Müller, MS 30, CPT, and C-stem THAs was above the acceptable limit for 10-year survival.

Fracture of the C-Stem cemented femoral component in revision hip surgery using bone impaction grafting technique: report of 9 cases

We present a series of 9 fractures of a C-Stem femoral component (6 long stems and 3 conventional stems) that had been implanted with the use of impaction bone grafting (IBG). The length of the long fractured stems was 240 mm in 4 cases and 200 mm in 2. The patients presented had an average BMI of 26.5 and an average of 2.7 previous hip surgeries (range 2-5 surgeries) before the stem fracture. A total of 5 cases presented with a metal mesh fracture in addition to the fractured stem. Bending of the stems or stem defects was not observed in any case. Typical fracture waves consistent with fatigue failure were clearly visible on all the cut surfaces, starting anterolaterally and propagating to the medial side. Although fatigue fracture of a modern cemented tapered polished femoral stem is a rare event, stress due to the absence of proximal femoral bone support could be sufficient to put this stem at a higher risk for fatigue fracture in non-obese patients.

Triple taper stem design shows promising fixation and bone remodelling characteristics: radiostereometric analysis in a randomised controlled trial

Cemented femoral stems with force closed fixation designs have shown good clinical results despite high early subsidence. A new triple-tapered stem in this category (C-stem AMT) was introduced in 2005. This study compares this new stem with an established stem of similar design (Exeter) in terms of migration (as measured using radiostereometric analysis), peri-prosthetic bone remodelling (measured using dual energy x-ray densitometry, DXA), Oxford Hip Score, and plain radiographs. A total of 70 patients (70 hips) with a mean age of 66 years (53 to 78) were followed for two years. Owing to missing data of miscellaneous reasons, the final analysis represents data from 51 (RSA) and 65 (DXA) patients. Both stems showed a typical pattern of migration: Subsidence and retroversion that primarily occurred during the first three months. C-stem AMT subsided less during the first three months (p = 0.01), before stabilising at a subsidence rate similar to the Exeter stem from years one to two. The rate of migration into retroversion was slightly higher for C-stem AMT during the second year (p = 0.03). Whilst there were slight differences in movement patterns between the stems, the C-stem AMT exhibits good early clinical outcomes and displays a pattern of migration and bone remodelling that predicts good clinical performance.

Cement in cement revision of the femoral component using a collarless triple taper: a midterm clinical and radiographic assessment

This study describes the midterm clinical and radiological results of the cement in cement technique for the femur using a collarless triple taper. Radiographic assessment was made retrospectively from 44 patients at two time points. Clinical outcomes included the Oxford Hip Score, EQ5D and Self Reported Patient Satisfaction Scale. Implant and patient survival were also recorded. The mean clinical follow up period was 5years 3months and the radiological follow up 2years 10months. The mean OHS was 34, the mean EQ5D 0.814 and the mean SAPS 94. Kaplan-Meier survival with revision, as the end point was 95.2% at 11years with a survivorship of 76.5% with death as the end point. Cement in cement revision using a collarless triple tapered stem demonstrates promising results both clinically and radiologically at midterm follow up.

Continuous distal migration and internal rotation of the C-stem prosthesis without any adverse clinical effects: an RSA study of 33 primary total hip arthroplasties followed for up to ten years

In 2005, we demonstrated that the polished triple-tapered C-stem at two years had migrated distally and rotated internally. From that series, 33 patients have now been followed radiologically, clinically and by radiostereometric analysis (RSA) for up to ten years. The distal migration within the cement mantle had continued and reached a mean of 2 mm (0.5 to 4.0) at ten years. Internal rotation, also within the cement mantle, was a mean 3.8° (external 1.6° to internal 6.6°) The cement mantle did not show any sign of migration or loosening in relation to the femoral bone. There were no clinical or radiological signs indicating that the migration or rotation within the cement mantle had had any adverse effects for the patients.