Abstract
-
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
Introduction
Total hip replacement is a safe, reliable and effective treatment for end-stage arthritis and has been hailed as ‘the operation of the century’. 1 Sir John Charnley is credited with the creation of the ‘modern’ total hip replacement, and his low-friction arthroplasty produced excellent long-term results. 2 The original polished, cemented flatback stem functioned as a taper 3,4 but subsequent changes to the design changed it into a composite beam. 5
Taper-slip, or force-closed, cemented polished femoral implants are designed to subside within the cement mantle in order to distribute load in a more physiological fashion. 6 This differs to the composite beam, or shape-closed designs, where fixation is required at all interfaces and subsidence signifies loosening. 7 The modern taper-slip stems now dominate the cemented hip market in the United Kingdom, with both double and triple-tapered designs available, but despite their popularity and increasingly widespread use, the magnitude and duration of subsidence have not yet been fully established. 8,9
The literature on the subsidence of polished taper-slip stems at different time intervals was reviewed in order to establish the levels compatible with excellent long-term survivorship, as well as any differences between double and triple-tapered designs, or the methods used to measure the subsidence.
Methods
Search strategy and criteria
Embase, MEDLINE and CINAHL databases were searched for all relevant articles from their inception until October 2020 (search strategies are presented in Table 1). The searches were performed in duplicate by two authors (KB and DHS). Citations within the selected articles, were also examined for their relevance. All articles meeting the inclusion criteria were evaluated.
Search strategies
| Database | Search terms |
|---|---|
| CINAHL | “(stem subsidence polished taper-slip stem).ti,ab OR (stem subsidence polished taper slip stem).ti,ab OR (stem subsidence polished force-closed stem).ti,ab OR (stem subsidence polished force closed stem).ti,ab OR (stem subsidence polished tapered stem).ti,ab OR (stem subsidence polished cemented stem).ti,ab” |
| MEDLINE | “(subsidence polished taper-slip stem).ti,ab OR (subsidence polished taper slip stem).ti,ab OR (subsidence polished force-closed stem).ti,ab OR (subsidence polished force closed stem).ti,ab OR (subsidence polished cemented stem).ti,ab OR (subsidence polished tapered stem).ti,ab” |
| Embase | “(subsidence polished force-closed stem).ti,ab OR (subsidence polished force closed stem).ti,ab OR (subsidence polished taper-slip stem).ti,ab OR (subsidence polished taper slip stem).ti,ab OR (subsidence polished tapered stem).ti,ab OR (subsidence polished cemented stem).ti,ab” |
The inclusion criteria were papers which included patients undergoing primary cemented total hip replacement, using a polished, force-closed or taper-slip stem and quoting a value for subsidence. Exclusion criteria included any papers not meeting the inclusion criteria, papers unavailable in English, prostheses not in clinical use, collared prostheses, and abstracts. Eligible studies were randomized and non-randomized controlled trials, cohort or case-control studies and case series.
If there was more than one paper reporting on the same patient cohort, the earlier one was removed, but the subsidence result retained to calculate average annual subsidence rates. Where there was disagreement between authors, resolution was achieved with discussion; however, where discussion did not result in consensus, the senior author (DHS) was final arbiter. After applying the inclusion and exclusion criteria, 28 papers were selected.
Data collection and analysis
The review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. 10 All search results had full title and abstract reviewed. Inclusion and exclusion criteria were then applied, and agreement confirmed by two authors (KB and DHS). Those whose abstracts met the inclusion criteria then had the full article reviewed and those found to be relevant were included in this review (Fig. 1).
Demographic data were collected including age, gender, body mass index (BMI), pre-operative diagnosis, duration of follow-up, the number of hips enrolled and the number available for final radiological review. Clinical data included implant type, stem geometry, surgical approach, cement and cementing technique, Oxford (OHS), 11 and Harris Hip Scores (HHS), 12 and survivorship. Radiological data included the method of radiographic analysis, Barrack grading of the cement mantle, 13 distal femoral cortical hypertrophy, direction of migration and subsidence.
Data were extracted from the papers by systematic analysis of each article and summarization in Microsoft Excel version 2013 (Microsoft, Redmond, WA, USA).
Quality appraisal
An assessment of the quality of the papers was performed using the National Heart, Lung, and Blood Institute (NIH) Quality assessment tools 14 by two authors (KB and DHS). Each study was rated good, fair or poor and where there were disagreements in rating, these were resolved through discussion with a consensus being reached in each case.
Statistical analysis
Statistical analysis was performed using SAS software (SAS, Marlow, Buckinghamshire, UK). Each study outcome was weighted by the number of patients in that study to assign higher weights to more precise mean estimates and vice versa. Studies that were assigned larger weights were more influential in determining the parameter estimates compared to studies that had smaller weights. The normality of the response variable was assessed via QQ plots, with a view to determine whether log transformation of the data was required. The statistical analyses involved a range of tests specific for continuous response variables including independent sample t-tests and Analysis of Variance.
Results
Study characteristics
After application of the inclusion and exclusion criteria, 28 papers were selected. 8,15–41 In total, 3090 hips were originally recruited to the studies, with 2099 being available for radiological review at final follow-up (67.9%). Average patient age was 68 years (42–70 years), 60.4% were female and the average BMI was 27.4 kg/m2 (24.1–29.2) (Table 2).
Study demographics
| Paper | Stem design |
Average patient age |
Gender (% female) | BMI (kg/m2) | Total number of hips enrolled | Hips radiologically analysed at final follow-up | % analysed at final follow-up |
|---|---|---|---|---|---|---|---|
| Alfaro-Adrian 1999 29 | Exeter | 66.0 | 50.0% | – | 14 | 14 | 100.0% |
| Glyn-Jones 2003 35 | Exeter a | 70.0 | – | – | 18 | 18 | 100.0% |
| Exeter b | 68.0 | – | – | 16 | 16 | 100.0% | |
| Exeter c | 68.0 | – | – | 12 | 12 | 100.0% | |
| Stefánsdóttir 2004 22 | Exeter | 63.0 | 40.9% | – | 22 | 22 | 100.0% |
| Glyn-Jones 2005 30 | Exeter | 70.0 | – | – | 21 | 21 | 100.0% |
| CPS Plus | 69.0 | – | – | 21 | 21 | 100.0% | |
| Nelissen 2005 40 | Exeter | 71.0 | – | 26.0 | 22 | 19 | 86.4% |
| Exeter | 71.0 | – | 26.0 | 19 | 11 | 57.9% | |
| Glyn-Jones 2006 31 | Exeter d | 68.0 | – | – | 19 | 19 | 100.0% |
| Exeter e | 70.0 | – | – | 26 | 26 | 100.0% | |
| Hook 2006 25 | Exeter | 61.0 | 64.9% | – | 142 | 86 | 60.6% |
| Li 2007 34 | Exeter | 70.5 | 36.4% | 26.6 | 11 | 11 | 100.0% |
| Lewthwaite 2008 27 | Exeter | 42.0 | – | – | 130 | 123 | 94.6% |
| Carrington 2009 24 | Exeter | 67.6 | 59.1% | – | 325 | 106 | 32.6% |
| Bohm 2012 32 | Exeter f | 73.0 | – | – | 21 | 14 | 66.7% |
| Exeter g | 72.0 | – | – | 20 | 11 | 55.0% | |
| Nieuwenhuijse 2012 39 | Exeter | 70.0 | 84.6% | – | 41 | 24 | 58.5% |
| Murray 2013 38 | Exeter | 63.0 | 50.0% | – | 20 | 20 | 100.0% |
| Park 2015 33 | Exeter | 57.0 | 42.9% | – | 91 | 91 | 100.0% |
| Westerman 2018 28 | Exeter | 67.7 | 62.8% | – | 540 | 374 | 69.3% |
| Clement 2019 23 | Exeter | 69.9 | 57.5% | – | 200 | 140 | 70.0% |
| Yates 2002 18 | CPT | 65.0 | 68.0% | – | 108 | 76 | 70.4% |
| Kaneuji 2006 36 | CPT | 69.1 | 81.6% | 24.1 | 42 | 42 | 100.0% |
| Yates 2008 17 | CPT | 62.3 | 70.0% | – | 191 | 120 | 62.8% |
| Burston 2012 15 | CPT | 60.0 | 64.4% | – | 191 | 90 | 47.1% |
| Jørgensen 2019 19 | CPT h | 76.0 | 48.0% | 29.0 | 25 | 24 | 96.0% |
| CPT i | 76.0 | 66.7% | 29.0 | 27 | 24 | 88.9% | |
| Ek 2005 26 | C-stem | 70.2 | 51.0% | 28.1 | 200 | 162 | 81.0% |
| Exeter | 68.4 | 59.8% | 28.5 | 205 | 145 | 70.7% | |
| Von Schewelov 2014 21 | C-stem | 66.0 | 57.6% | – | 36 | 14 | 38.9% |
| Flatøy 2015 8 | C-stem | 66.0 | 65.4% | 25.0 | 35 | 26 | 74.3% |
| Exeter | 65.0 | 76.0% | 28.0 | 34 | 25 | 73.5% | |
| Olerud 2014 20 | MS-30 j | 68.4 | 46.7% | 29.0 | 30 | 28 | 93.3% |
| MS-30 k | 68.4 | 71.4% | 29.2 | 21 | 19 | 90.5% | |
| Weber 2017 16 | MS-30 l | 69.0 | 43.3% | 29.0 | 30 | 10 | 33.3% |
| MS-30 m | 71.0 | 66.7% | 27.0 | 30 | 16 | 53.3% | |
| Madörin 2019 41 | TwinSys | 79.0 | 52.6% | 25.4 | 100 | 49 | 49.0% |
| McCalden 2010 37 | CPCS | 75.7 | 81.3% | – | 17 | 16 | 94.1% |
| Exeter | 77.9 | 85.7% | – | 17 | 14 | 82.4% | |
| Total | 68* | 60.9%* | 27.3* | 3090 | 2099 | 67.9% |
aWith simplex cement. bWith CMW3 cement. cWith CMW1 cement. dPosterior approach. eAnterolateral approach. fSimplex T cement. gSimplex P cement. hHi-faitgue G cement. iPalacos R+G cement. jPalacos cement. kRefobicin cement. lHollow centralizer. mSolid centralizer. *Average.
Sixteen studies measured subsidence using Radiostereometric Analysis (RSA), 8,16,19–22,29–32,34,35,37–40 10 used measurements on plain X-rays 15,17,18,24–28,33,36 and two used Ein Bild Roentgen Analyse (EBRA, Table 3). 23,41 Twelve papers used the HHS 15,17,21,24,26,28,33,36,37,39–41 and six the OHS. 8,19,24,25,28,38
Demographics by method of analysis
| Radiological analysis method | Number of hips recruited | Number of hips available for radiological analysis | Average age | Gender (% female) | BMI | Average follow-up (years) |
|---|---|---|---|---|---|---|
| Plain radiograph | 2165 | 1415 (65.4%) | 62.8 | 61.0% | 26.9 | 9.5 |
| RSA | 625 | 495 (79.2%) | 69.7 | 61.4% | 27.6 | 3.5 |
| EBRA | 300 | 189 (63.0%) | 74.5 | 55.9% | 25.4 | 3.5 |
Notes. RSA, Radiostereometric Analysis; EBRA, Ein Bild Roentgen Analyse; BMI, body mass index.
Quality assessment
Amongst the included studies were six randomized controlled trials. 8,16,19,32,37,40 All papers included in this study were assessed to be of good or fair quality.
Details of surgical technique
A single surgical approach was used in 16 studies, 8,16,30,33,37–40,18–23,25,29 with multiple approaches in nine 15,17,24,26,27,31,32,35,41 and three failing to detail the approach used (Table 4). 28,34,36
Study surgical technique and outcomes of interest
| Paper | Stem | Cement | Technique | Restrictor | Centralizer | Approach | Subsidence (mm) | Into valgus | DFCH | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1y | 2y | 5y | 10y | 12–13y | 15–16y | |||||||||
| Alfaro-Adrian 1999 29 | Exeter | CMW | 3rd generation | Y | Y | Anterolateral | 1.06 | 1.20 | – | – | – | – | – | – |
| Glyn-Jones 2003 35 | Exeter | Simplex | – | Y | – | Combination | 1.07 | – | – | – | – | – | Y | – |
| CMW3 | – | Y | – | Combination | 1.00 | – | – | – | – | – | Y | – | ||
| CMW1 | – | Y | – | Combination | 1.26 | – | – | – | – | – | Y | – | ||
| Stefánsdóttir 2004 22 | Exeter | Palcos with gent | – | – | – | Posterolateral | 1.23 | 1.34 | 1.77 | – | – | – | 22.73% | 2 |
| Glyn-Jones 2005 30 | Exeter | CMW3 | 3rd generation | – | – | Hardinge | – | 0.86 | – | – | – | – | Y | – |
| CPS Plus | CMW3 | 3rd generation | – | – | Hardinge | – | 0.67 | – | – | – | – | N | – | |
| Nelissen 2005 40 | Exeter | Simplex P | 3rd generation | – | Y | Lateral | 1.05 | 1.53 | – | – | – | – | 0% | – |
| Exeter | Simplex AF | 3rd generation | – | Y | Lateral | 0.95 | 1.12 | – | – | – | – | 0% | – | |
| Glyn-Jones 2006 31 | Exeter | CMW3G | 3rd generation | Y | – | Posterolateral | – | 1.15 | – | – | – | – | Y | – |
| Exeter | CMW3G | 3rd generation | Y | – | Hardinge | – | 1.01 | – | – | – | – | Y | – | |
| Hook 2006 25 | Exeter | Palacos R with gent | 2nd generation | Y | – | Posterolateral | – | 0.50 | – | – | 1.52 | – | 2.27% | 7 |
| Li 2007 34 | Exeter | – | – | Y | Y | – | – | 1.10 | 1.40 | – | – | – | Y | – |
| Lewthwaite 2008 27 | Exeter | – | – | Y | – | Combination | – | – | – | – | 1.29 | – | – | – |
| Carrington 2009 24 | Exeter | Simplex RO | 3rd generation | – | Y | Combination | – | – | – | 1.32 | – | 1.82 | – | 11 |
| Bohm 2012 32 | Exeter | Simplex T | 3rd generation | Y | – | Combination | – | 0.66 | – | – | – | – | – | – |
| Exeter | Simplex P | 3rd generation | Y | – | Combination | – | 0.71 | – | – | – | – | – | – | |
| Nieuwenhuijse 2012 39 | Exeter | Simplex AF / P | – | – | Y | Lateral | – | 1.42 | 1.89 | 2.13 | – | – | – | – |
| Murray 2013 38 | Exeter | – | – | Y | – | Anterolateral | – | 0.92 | – | 1.28 | – | – | – | – |
| Park 2015 33 | Exeter | Simplex | 3rd generation | Y | – | Hardinge | – | – | – | – | 1.90 | – | – | 3 |
| Westerman 2018 28 | Exeter | – | – | – | – | – | – | – | – | – | 1.20 | – | – | – |
| Clement 2019 23 | Exeter | – | – | – | – | Posterolateral | – | 1.20 | – | – | – | – | Y | – |
| Yates 2002 18 | CPT | Palacos R | 2nd generation | – | Y | Posterolateral | – | 1.08 | 2.18 | – | – | – | – | 5 |
| Kaneuji 2006 36 | CPT | Endurance CMW | 3rd generation | Y | – | – | 0.72 | – | – | – | – | – | – | – |
| Yates 2008 17 | CPT | Palacos R | 2nd generation | – | Y | Combination | 0.80 | – | – | – | – | – | 5.0% | 1 |
| Burston 2012 15 | CPT | Palacos R with gent | 2nd generation | Y | – | Combination | – | – | – | 1.95 | – | 2.10 | – | 0 |
| Jørgensen 2019 19 | CPT | Hi fatigue G | 3rd generation | – | – | Posterolateral | 0.91 | 1.12 | – | – | – | – | – | – |
| Palacos R+G | 3rd generation | – | – | Posterolateral | 1.03 | 1.19 | – | – | – | – | – | – | ||
| Ek 2005 26 | C-stem | Endurance CMW | 3rd generation | Y | Y | Anterolateral | – | 0.77 a | – | – | – | – | 2.5% | 0 |
| Exeter | Endurance CMW | 3rd generation | Y | Y | Combination | – | 0.82 b | – | – | – | – | – | 0 | |
| Flatøy 2015 8 | C-stem | Palacos R with gent | – | – | – | Hardinge | – | 1.28 | – | – | – | – | 11.5% | – |
| Exeter | Palacos R with gent | – | – | – | Hardinge | – | 1.67 | – | – | – | – | 12.0% | – | |
| Von Schewelov 2014 21 | C-stem | Palacos with gent | 3rd generation | Y | Y | Hardinge | – | 1.35 | 1.71 | 2.06 | – | – | – | – |
| Olerud 2014 20 | MS-30 | Palacos | 3rd generation | – | Y | Posterolateral | – | 1.40 | – | – | – | – | – | – |
| Refobicin | 3rd generation | – | Y | Posterolateral | – | 1.28 | – | – | – | – | – | – | ||
| Weber 2017 16 | MS-30 | Palacos with gent | 3rd generation | – | Y- Hollow | Posterolateral | 1.21 | 1.40 | 1.74 | 1.99 | – | – | – | – |
| MS-30 | Palacos with gent | 3rd generation | – | Y- Solid | Posterolateral | 0.28 | 0.28 | 0.36 | 0.57 | – | – | – | – | |
| Madörin 2019 41 | twinSys | Palacos R+G | 3rd generation | Y | – | Combination | – | 0.40 | 0.70 | – | – | – | 14.0% | – |
| McCalden 2010 37 | CPCS | Simplex | – | – | – | Hardinge | – | 0.77 | – | – | – | – | Y | – |
| Exeter | Simplex | – | – | – | Hardinge | – | 1.25 | – | – | – | – | – | – | |
Notes. DFCH, distal femoral cortical hypertrophy.
aMean at 2.4 years. bMean at 2.6 years.
Third generation femoral cementing was used in 14 studies 16,19–21,24,26,29–33,36,40,41 and second generation in four. 15,17,18,25 Ten studies failed to specify the cementing technique used 8,22,23,27,28,34,35,37–39 and five of these also failed to specify the type of cement. 23,27,28,34,38 Nine studies documented the use of a centralizer 16,20,21,24,26,29,33,39,40 and 15 the use of a restrictor (Table 4). 15,17,18,21,25–27,29,31–33,35,36,38,41
The type of acetabular component was specified in 20 of the papers, 8,15,17–20,23–28,31–33,35–37,39,41 with 10 using a consistent femoral and acetabular implant combination. 8,19,20,23,31,32,35–37,39 A single acetabular design was used in eight studies, five being cemented 8,23,31,35,39 and three uncemented. 19,32,36
Clinical outcomes
Of the 12 papers that used the HHS, 15,17,21,24,26,28,33,36,37,39,40,41 11 had both pre-operative and post-operative scores. The average pre-operative score was 42.4, improving to 84.7 after surgery at an average follow-up of 7.1 years. 15,17,21,26,28,33,36,37,39,40,41
The OHS was used in six papers, 8,19,24,25,28,38 but only two included both pre-operative and post-operative results, with an average pre-operative OHS of 20.4 improving to 42.0 at an average follow-up of 5.5 years. 8,28
Radiological outcomes
There were 2099 hips available at the time of the final radiological review, 1759 double-tapers (83.8%) and 340 triple-tapers (16.2%) (Tables 5 and 6). Thirteen papers included the Barrack grading, 8,15,17–19,25–28,33,36,40,41 with the majority of the hips being Grade A or B (Table 7). Eight papers specifically commented on distal femoral cortical hypertrophy (DFCH). 15,17,18,22,24–26,33 Two papers reported the absence of DFCH. 15,26 The six papers reporting its presence featured the use of double-tapered stems, with the reported incidence ranging from 0.83% to 10.3% (Table 4). 17,18,22,24,25,33
Demographics by stem geometry
| Stem geometry | Number of hips recruited | Number of hips available for radiological analysis | Average age | Gender (% female) | BMI | Average follow-up (years) |
|---|---|---|---|---|---|---|
| Double taper | 2591 | 1759 (67.9%) | 67.3 | 61.8% | 27.2 | 5.1 |
| Triple taper | 499 | 340 (68.1%) | 70.4 | 54.7% | 27.5 | 5.0 |
Notes. BMI, body mass index.
Summary of prosthesis used and numbers at final radiological follow-up
| Prosthesis | Papers used | Number of hips available for radiological review | |
|---|---|---|---|
| Double taper (1759 hips)* | Exeter | Ek 26 , Flatøy 8 , Glyn-Jones 2003 35 , 2005 30 & 2006 31 , McCalden 37 , Murray 38 , Nieuwenhuijse 39 , Nelissen 40 , Stefánsdóttir 22 , Clement 23 , Carrington 24 , Hook 25 , Lewthwaite 27 , Westerman 28 , Alfaro-Adrian 29 , Bohm 32 , Park 33 , Li 34 | 1362 (77.4%) |
| CPT | Burston 15 , Kaneuji 36 , Yates 2002 18 & 2008 17 , Jørgensen 19 | 376 (21.4%) | |
| CPS plus | Glyn-Jones 2005 30 | 21 (1.2%) | |
| Triple taper (340 hips)* |
C-stem | Ek 26 , Flatøy 8 , von Schewelov 21 | 202 (59.4%) |
| MS-30 | Weber 16 , Olerud 20 | 73 (21.5%) | |
| TwinSys | Madörin 41 | 49 (14.4%) | |
| CPCS | McCalden 37 | 16 (4.7%) |
*Hips available for radiological review at final follow-up.
Summary of papers quoting the Barrack grading of cement mantles
| Paper | Prosthesis | Barrack A | Barrack B | Barrack C | Barrack D |
|---|---|---|---|---|---|
| Nelissen 2005 40 | Exeter | 30.00% | 70.00% | – | – |
| 68.42% | 31.58% | – | – | ||
| Hook 2006 25 | Exeter | 72.00% | 0.00% | 24.00% | 4.00% |
| Lewthwaite 2008 27 | Exeter | 33.33% | 42.50% | 22.50% | 1.67% |
| Park 2015 33 | Exeter | 54.95% | 35.16% | 9.89% | 0.00% |
| Westerman 2018 28 | Exeter | 73.60% | 25.00% | 1.40% | 0.00% |
| Yates 2002 18 | CPT | 67.10% | 2.60% | 30.30% | 0.00% |
| Kaneuji 2006 36 | CPT | 30.95% | 42.86% | 26.19% | 0.00% |
| Yates 2008 17 | CPT | 76.00% | 0.00% | 20.00% | 3.30% |
| Burston 2012 15 | CPT | 72.00% | 0.00% | 23.00% | 5.00% |
| Jørgensen 2019 19 | CPT a | 96.00% | 4.00% | 0.00% | 0.00% |
| CPT b | 57.69% | 38.46% | 3.85% | 0.00% | |
| EK 2005 26 | C-Stem | 45.70% | 46.30% | 8.00% | 0.00% |
| Exeter | 36.50% | 56.60% | 6.90% | 0.00% | |
| Flatøy 2015 8 | C-Stem | 34.62% | 50.00% | 15.38% | 0.00% |
| Exeter | 36.00% | 52.00% | 12.00% | 0.00% | |
| Madörin 2019 41 | twinSys | 47.00% | 44.00% | 7.00% | 1.00% |
aHi Fatigue. bPalacos R&G.
Subsidence at one year
Eight papers quoted one-year subsidence values (Table 8), 16,17,19,22,29,35,36,40 with four looking at different variables using the same prosthesis. 16,19,35,40 The overall mean subsidence at one year was 0.97 mm, for double-tapers it was 1.01 mm and for triple-tapers 0.75 mm. Six papers used RSA and two used radiographs. The mean subsidence for the RSA papers was 1.00 mm and for radiograph papers 0.76 mm (Table 9). There was no significant difference between the subsidence of double and triple-tapered implants at one year (p = 0.2432).
Summary of subsidence values at time intervals
| Year | Paper | Prosthesis | Radiographic Analysis |
Subsidence | Mean subsidence at time |
|---|---|---|---|---|---|
| 1 Year | Alfaro-Adrian 1999 29 | Exeter | RSA | 1.06 mm | 0.97 mm |
| Glyn-Jones 2003 35 | Exeter | RSA | 1.07 mm 1.00 mm 1.26 mm |
||
| Stefánsdóttir 2004 22 | Exeter | RSA | 1.23 mm | ||
| Nelissen 2005 40 | Exeter | RSA | 1.05 mm 0.95 mm |
||
| Kaneuji 2006 36 | CPT | X-ray | 0.72 mm | ||
| Yates 2008 17 | CPT | X-ray | 0.80 mm | ||
| Jørgensen 2019 19 | CPT | RSA | 0.91 mm 1.03 mm |
||
| Weber 2017 16 | MS-30* | RSA | 1.21 mm 0.28 mm |
||
| 2 Years | Alfaro-Adrian 1999 29 | Exeter | RSA | 1.20 mm | 1.07 mm |
| Stefánsdóttir 2004 22 | Exeter | RSA | 1.34 mm | ||
| Glyn-Jones 2005 30 | Exeter CPS Plus |
RSA | 0.86 mm 0.67 mm |
||
| Nelissen 2005 40 | Exeter | RSA | 1.53 mm 1.12 mm |
||
| Glyn Jones 2006 31 | Exeter | RSA | 1.15 mm 1.01 mm |
||
| Hook 2006 25 | Exeter | X-ray | 0.50 mm | ||
| Li 2007 34 | Exeter | RSA | 1.10 mm | ||
| Bohm 2012 32 | Exeter | RSA | 0.66 mm 0.71 mm |
||
| Nieuwenhuijse 2012 39 | Exeter | RSA | 1.42 mm | ||
| Murray 2013 38 | Exeter | RSA | 0.92 mm | ||
| Clement 2019 23 | Exeter | EBRA | 1.20 mm | ||
| Yates 2002 18 | CPT | X-ray | 1.08 mm | ||
| Jørgensen 2019 19 | CPT | RSA | 1.12 mm 1.19 mm |
||
| Von Schewelov 2014 21 | C-Stem* | RSA | 1.35 mm | ||
| Flatøy 2015 8 | C-Stem*
Exeter |
RSA | 1.28 mm 1.67 mm |
||
| Olerud 2014 20 | MS-30* | RSA | 1.40 mm 1.28 mm |
||
| Weber 2017 16 | MS-30* | RSA | 1.40 mm 0.28 mm |
||
| Madörin 2019 41 | TwinSys* | EBRA | 0.40 mm | ||
| McCalden 2010 37 | CPCS*
Exeter |
RSA | 0.77 mm 1.25 mm |
||
| 5 years | Stefánsdóttir 2004 22 | Exeter | RSA | 1.77 mm | 1.47 mm |
| Li 2007 34 | Exeter | RSA | 1.40 mm | ||
| Nieuwenhuijse 2012 39 | Exeter | RSA | 1.89 mm | ||
| Yates 2002 18 | CPT | X-ray | 2.18 mm | ||
| Von Schewelov 2014 21 | C-Stem* | RSA | 1.71 mm | ||
| Weber 2017 16 | MS-30* | RSA | 1.74 mm 0.36 mm |
||
| Madörin 2019 41 | TwinSys* | EBRA | 0.70 mm | ||
| 10 years | Carrington 2009 24 | Exeter | X-ray | 1.32 mm | 1.61 mm |
| Nieuwenhuijse 2012 39 | Exeter | RSA | 2.13 mm | ||
| Murray 2013 38 | Exeter | RSA | 1.28 mm | ||
| Burston 2012 15 | CPT | X-ray | 1.95 mm | ||
| Von Schewelov 2014 21 | C-stem* | RSA | 2.06 mm | ||
| Weber 2017 16 | MS-30* | RSA | 1.99 mm 0.57 mm |
||
| 12–13 years | Hook 2006 25 | Exeter | X-ray | 1.52 mm | 1.48 mm |
| Lewthwaite 2008 27 | Exeter | X-ray | 1.29 mm | ||
| Westerman 2018 28 | Exeter | X-ray | 1.20 mm | ||
| Park 2015 33 | Exeter | X-ray | 1.90 mm | ||
| 15–16 years | Carrington 2009 24 | Exeter | X-ray | 1.82 mm | 1.96 mm |
| Burston 2012 15 | CPT | X-ray | 2.10 mm |
Notes. RSA, Radiostereometric Analysis; EBRA, Ein Bild Roentgen Analyse.
*Denotes triple-tapered stem.
Summary of subsidence values
| Time (years) | Subsidence (mm) | Stem design | Method of subsidence measurement | |||
|---|---|---|---|---|---|---|
| Overall | Double taper | Triple taper | RSA | Radiograph | EBRA | |
| 1 | 0.97 | 1.01 | 0.75 | 1.00 | 0.76 | – |
| 2 | 1.07 | 1.04 | 1.02 | 1.11 | 0.79 | 0.80 |
| 5 | 1.47 | 1.81 | 1.13 | 1.48 | 2.18* | 0.70* |
| 10 | 1.61 | 1.67 | 1.54 | 1.61 | 1.64 | – |
| 12–13 | 1.48 | 1.48 | – | – | 1.48 | – |
| 15–16 | 1.96 | 1.96 | – | – | 1.96 | – |
*Based on one paper.
Subsidence at two years
Nineteen studies reported subsidence at two years 8,16,18–23,25,29–32,34,37–41 and three of these reported two-year data consistent with the trends demonstrated at one year (Table 8). 16,19,40 The overall mean subsidence at two years was 1.07 mm, for double-tapers it was 1.04 mm and for triple-tapers 1.02 mm. Fifteen papers used RSA, two used EBRA and two used radiographs. Mean subsidence for the RSA papers was 1.11 mm, for EBRA it was 0.80 mm and for radiograph papers it was 0.79 mm (Table 9). There was no significant difference between the subsidence of double and triple-tapered implants at two years (p = 0.4535).
Subsidence at five years
Seven papers reported subsidence at five years (Table 8), 16,18,21,22,34,39,41 with three studies again reporting results consistent with their one and/or two-year findings. 16,21,39 The overall mean subsidence at five years was 1.47 mm, for double-tapers it was 1.81 mm and for triple-tapers 1.13 mm. Five papers used RSA, one used EBRA and one used radiographs. Mean subsidence for the RSA papers was 1.48 mm, for EBRA was 0.70 mm and for the single radiograph paper 2.18 mm (Table 9). There was no significant difference between the subsidence of double and triple-tapered implants at five years (p = 0.0787).
Subsidence at 10 years
Six papers reported a 10-year subsidence value (Table 8), 15,16,21,24,38,39 with three papers again reporting results consistent with their earlier findings. 16,21,39 The overall mean 10-year subsidence was 1.61 mm, for double-tapers it was 1.67 mm and for triple-tapers 1.54 mm. Four papers used RSA and two used radiographs. Mean subsidence for the RSA papers was 1.61 mm and for the radiograph papers was 1.64 mm (Table 9). There was no difference between the subsidence of double and triple-tapered implants at 10 years (p = 0.4535).
Subsidence at other time points
Four papers reported subsidence between 11 and 14 years with a mean follow-up of 12.6 years. All four used double-tapered stems and radiographs to assess subsidence, with a mean subsidence of 1.48 mm (Tables 8 and 9). 25,27,28,33 Two papers reported mean subsidence between 15 and 16 years with a mean follow-up of 15.8 years. Both used double-tapered stems and radiographs to assess subsidence, with a mean subsidence of 1.96 mm (Tables 8 and 9). 15,24
Migration into valgus
Thirteen papers commented on the presence or absence of migration into valgus (Table 4), 8,17,22,23,25,26,30,31,34,35,37,40,41 with six reporting that the stem migrated into a more valgus alignment. 8,17,22,25,26,41
Mean overall subsidence
To explore the effect of the method of radiological evaluation on mean overall subsidence, a weighted Analysis of Variance (ANOVA) was performed, which found no significant difference between the methods (p = 0.4295). The pairwise contrasts between each type of measurement demonstrated no statistically significant difference between any pair of measurement types (EBRA vs. radiographic, p = 0.2245; EBRA vs. RSA, p = 0.4785; and radiographic vs. RSA, p = 0.5314).
The mean overall subsidence in double and triple-tapered stems was 1.33 mm and 0.91 mm respectively, and this difference was significant and remained so even after controlling for radiological measurement type (p = 0.0342).
Subsidence rates
In addition to the mean subsidence values, a calculation was performed on all papers offering one or two-year subsidence rates with subsequent five or 10-year values, in order to work out subsidence rates over time (Table 10). Rates were calculated by subtracting the one or two-year value from the five or 10-year value and dividing by the difference in years. For example: (five-year value – one year value) ÷ (five – one).
Calculated subsidence rates
| Paper | Stem | Subsidence rate per year (mm) | |||
|---|---|---|---|---|---|
| 1–5 years | 2–5 years | 1–10 years | 2–10 years |
||
| Stefánsdóttir 2004 22 | Exeter | 0.14 | 0.11 | – | – |
| Li 2007 34 | Exeter | – | 0.10 | – | – |
| Nieuwenhuijse 2012 39 | Exeter | – | 0.16 | – | 0.09 |
| Murray 2013 38 | Exeter | – | – | – | 0.05 |
| Yates 2002 18 | CPT | – | 0.37 | – | – |
| Madörin 2019 41 | twinSys* | – | 0.10 | – | – |
| Von Schewelov 2014 21 | C-stem* | – | 0.12 | – | 0.09 |
| Weber 2017 16 | MS-301* | 0.13 | 0.11 | 0.09 | 0.07 |
| MS-302* | 0.02 | 0.03 | 0.03 | 0.04 | |
aHollow centralizer. bSolid centralizer. *Triple-tapered stem.
There was no significant difference in subsidence between double-tapered and triple-tapered stems between two and five years (p = 0.2017) or between two and 10 years (p = 0.8982) (Table 10).
Discussion
Despite the already widespread use and increasing popularity of cemented, polished femoral implants adhering to the taper-slip philosophy, the magnitude and duration of subsidence compatible with excellent clinical performance and survivorship has yet to be fully established. Previous studies have attempted to establish a threshold for migration at two years, above which a high probability of failure could be predicted. 42–45 A wide range of levels has been suggested, from 0.15 to 1.2 mm, 42,43,45 but these were all based on the performance of composite beam stems, which were not designed to subside and could not therefore be applied to taper-slip implants. 44,46–48
Teeter et al, 44 using the thresholds proposed by Kärrholm et al and van der Voort et al, 42,45 examined subsidence with three stem designs, one composite beam and two taper-slip. They found that whilst the taper-slip stems exceeded the proposed subsidence threshold at two years, the composite beam did not. Despite this, the 10-year revision rates for the taper-slip Exeter (Stryker-Howmedica, Middlesex, UK) and CPCS (Smith & Nephew, Memphis, USA) stems were 3.9% and 4.3% respectively compared to 5.6% with the composite beam Spectron EF (Smith & Nephew, Memphis, USA). 44
The current review reports the subsidence of taper-slip stems up to a mean of 15.8 years and found that at all time points, the double-tapered stems subsided more than the triple-tapers, but that this did not reach statistical significance (p = 0.2432, 0.4535, 0.0787 and 0.7256 at one, two, five and 10 years respectively). The difference in mean overall subsidence between double and triple-tapered stems was statistically significant (1.33 mm vs. 0.91 mm; p = 0.0342), however, there is no evidence that this resulted in clinical significance.
The addition of a third taper, running from the lateral shoulder to the medial aspect of the implant, is designed to produce more physiological loading of the proximal femur leading to better stress distribution through the cement mantle 49 and a reduction in negative bone remodelling with time.
The current review found that double-tapered stems have a higher rate of migration in the first year compared with triple-tapers, but between years one and two, triple-tapered stems subside at a greater rate. There was no significant difference in subsidence at any time point between the two stem geometries. However, mean overall subsidence was significantly affected by stem geometry (double versus triple tapers).
When directly comparing double and triple-tapered stems, Flatøy et al found significantly lower subsidence at three months for triple-tapers, but during the second year, the rate was similar. 8 McCalden et al found a significantly reduced level of subsidence in triple-tapers at two years and proposed that the broader proximal cross-section of the CPCS stem was a factor in reducing subsidence compared to the Exeter, 37 whereas Ek et al and Jayasuriya et al found similar levels of subsidence at all time points. 26,50
The method of measuring subsidence varied between studies, with the majority being RSA based. RSA has been used to study early stem migration and correctly predicted the poor long-term performance of the composite beam Charnley Elite-Plus stem (De Puy International, Leeds, UK). 51 Other studies have, however, demonstrated that such predictions are not always accurate. 21,52
In 1999, Nivbrant et al reported early RSA results for the composite beam Scientific Hip Prosthesis (Biomet, Indiana, USA), finding increased subsidence and retroversion, suggesting the likelihood of failure. 53 However, when Van de Groes et al reported the longer-term results in 2012, they found a satisfactory survival rate of 98.8% at 10 years. 52 In 2005, Sundberg et al reported two-year RSA results for the triple-tapered C-stem, finding increased posterior migration and retroversion, which were predicted to result in a high failure rate. 54 These fears were subsequently dispelled by von Schewelov et al in 2014 who reported excellent 10-year results for the same cohort, 21 indicating that caution should be used when interpreting early RSA results, especially when the long-term pattern of migration of a particular implant is not known.
In this systematic review, cohorts analysed using RSA were usually of less than 30 patients with high levels of exclusion due to technical issues including poor image quality or loss of markers (Table 2). Despite these limitations, RSA is seen as the current gold standard for assessment of migration due to its accuracy in detecting outlier implants. 42 EBRA was used in only two papers and had a similarly high exclusion rate due to the requirement for a minimum number of standardized radiographs. However, the use of EBRA has been shown to improve the accuracy of migration assessment, particularly vertically, compared to plain radiographic measurements (Table 2). 55 The measurement of plain radiographs using the Fowler technique 56 was the second most frequently used method, with these papers having larger patient numbers and longer follow-up. The benefit of the Fowler technique is that special markers and or software are not required to perform the migration assessment. However, this means that the accuracy of measurements are operator dependent and can vary depending on the position and magnification of the radiograph.
At one year, Glyn-Jones et al found that different cement viscosities had no effect on subsidence with Exeter stems 35 and Nelissen et al found no association between cement viscosity, mantle thickness and migration. 40 Jørgensen et al found no significant difference in subsidence between two types of cement, 19 but Weber et al found a significantly increased subsidence when using a hollow rather than a solid centralizer. 16
At two years there was no statistically significant difference between the distal migration of Exeter and CPS Plus double-tapered stems, although subsidence, internal rotation and valgus angulation were lower in the CPS Plus stem, which had a wider, more rectangular proximal section. 30 Two papers demonstrated lower subsidence in triple-tapered stems compared to doubles 8,37 (Tables 6 and 7) and two more concluded that there were no significant differences in subsidence rates due to the use of different antibiotics in the cement. 20,32 Glyn-Jones et al found no statistically significant difference in distal subsidence between posterior and anterolateral approaches, although the posterior approach group had significantly higher posterior head migration (1.27 vs. 0.77 mm) and internal rotation (1.94 vs. 1.16 degrees). 31
The mean subsidence at two years based on plain radiographic measurements and EBRA was similar (0.79 mm vs. 0.80 mm) and the mean subsidence at 10 years, reported in papers based on both RSA and plain radiographic measurements was again similar (1.62 mm vs. 1.64 mm). Our analysis found no significant difference between the method of measurement used and the effect on reported subsidence (Table 9).
Two of the three studies comparing a double-tapered stem with a triple-taper reported that the triple-taper migrated into valgus whilst the double-taper tended to migrate into varus, 29,34 whereas Flatøy et al reported both designs migrating into valgus. 8 Glyn-Jones et al compared the use of three different types of cement describing valgus migration with a double-tapered stem in all three cohorts 35 and in a comparison of the posterior with the anterolateral approach, both demonstrated migration into valgus, but there was no significant difference in the amount produced. 31 In a study of two different double-tapered stems, the CPS Plus (Endoplus, Swindon, UK) with a wider, more rectangular proximal section, did not migrate into valgus or internal rotation compared with the Exeter stem which did (Stryker-Howmedica, Middlesex, UK), 30 suggesting that the specifics of the geometry of a design were integral to the rate of subsidence and not just the number of planes that tapered.
Barrack grading of the cement mantle has been demonstrated to be an independent predictor of stem failure. 13 Several studies reported a significant increase in subsidence with increasing Barrack grade, 18,41,57,58 whilst others did not. 15,17,28 Yates et al found that implants with a Grade A mantle had subsided less than those with a Grade D at 10 years (1.67 mm vs. 2.5 mm), but that this was not statistically significant 17 and Hook et al reported higher subsidence with an increased Barrack grade but did not comment on the significance. 25 There was therefore no clear agreement as to whether Barrack grade is related to subsidence, but, in any case, increased subsidence is not necessarily detrimental to the overall performance of taper-slip stems.
The presence or absence of DFCH was reported in eight papers (Table 7), six of which had patients with DFCH. Two studies reported that the presence of DFCH was not related to subsidence, although Yates et al found that DFCH occurred twice as frequently in hips with cement mantle defects. 18,25 Park et al found that patients with DFCH had less subsidence than the overall mean (< 1 mm vs. 1.90 mm) 33 and Carrington et al found a similar trend (1.59 mm vs. 1.82 mm). 24 Both papers concluded that DFCH was related to the use of larger stems, which subsided less. Only one paper specifically mentioned clinical outcome with regard to DFCH, stating there was no correlation between DFCH and poor clinical outcome. 22 This is in keeping with the literature, where the outcome of patients displaying DFCH was no worse than those not displaying DFCH. 59–61
This systematic review is strengthened by the large number of papers included; the largest cohort in the literature for taper-slip stems. The papers covered a range of implants, including the Exeter stem, the most frequently used double-taper, and the C-stem, the most frequently used triple-taper. The papers included also covered a wide age range of patients, from a mean of 42 to a mean of 77.9 and values for subsidence consistent with good clinical results at a wide range of different time points ranging from one to more than 15 years. Amongst the included studies were six randomized controlled trials 8,16,19,32,37,40 further strengthening the evidence presented in this review.
The large dropout rates between initial recruitment and final radiological analysis (31.4%) were to be expected. In the papers with long-term follow-up this was inevitable, due to the expected patient death rates, and in the shorter-term RSA and EBRA studies this was the result of technical issues due to insufficient or technically inadequate radiographs. Whilst the dropout rates varied between papers, each study outcome was weighted according to the number of patients in that study such that greater patient numbers led to a higher weight being assigned to the study.
There was a lack of clarity in many papers regarding the type of cement used and the cementing technique making establishing the significance of these difficult. Of note, however, is the fact that in the papers comparing different cement types, no significant difference in subsidence was found. 19,20,32,35,40 There was also heterogeneity in the surgical approaches used, which potentially affects the interpretation of results due to the lack of standardization, although Glyn-Jones et al using a single implant and cement combination, concluded that the surgical approach used was not related to the magnitude of distal migration. 31
There is, however, a potential bias towards the double-tapered stems in reporting, as they outnumbered the triple-tapered stems in hips recruited (2591 vs. 499) and in those analysed at final radiological follow-up (1759 vs. 340), although the studies directly comparing the two designs of stem found similar outcomes irrespective of subsidence. 8,26,37
Conclusion
This systematic review evaluated the subsidence levels reported for clinically successful taper-slip stems at one, two, five and 10 years and found that the method used to measure subsidence did not have a significant influence. Whilst a subsidence threshold beyond which failure is more likely to occur could not be established based solely on the literature, the review reports the levels of subsidence at which clinical outcomes and survivorship remain excellent. More studies are, however, required into the longer-term performance of the triple-tapered stems, but as no significant differences were found in the subsidence between the two designs, the values set forth here can be applied to all taper-slip stems.
Open access
This article is distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC BY-NC 4.0) licence (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed.
The authors declare no conflict of interest relevant to this work.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This article is distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC BY-NC 4.0) licence (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed.
References
- 1.↑
Learmonth ID , Young C , Rorabeck C . The operation of the century: total hip replacement. Lancet 2007; 370:1508–1519 .
- 2.↑
Wroblewski BM , Siney PD , Fleming PA . Charnley low-frictional torque arthroplasty: follow-up for 30 to 40 years. J Bone Joint Surg Br 2009; 91:447–450 .
- 3.↑
Loudon JR Jr , Charnley J . Subsidence of the femoral prosthesis in total hip replacement in relation to the design of the stem. J Bone Joint Surg Br 1980; 62-B:450–453 .
- 4.↑
Shen G . Femoral stem fixation: an engineering interpretation of the long-term outcome of Charnley and Exeter stems. J Bone Joint Surg Br 1998; 80:754–756 .
- 5.↑
Scheerlinck T , Casteleyn P-P . The design features of cemented femoral hip implants. J Bone Joint Surg Br 2006; 88:1409–1418 .
- 6.↑
Griza S , Gomes LSM , Cervieri A , Strohaecker TR . Migration and strains induced by different designs of force-closed stems for THA. Rev Bras Ortop (English Ed) 2015; 50:686–693 .
- 7.↑
Kazi HA , Whitehouse SL , Howell JR , Timperley AJ . Not all cemented hips are the same: a register-based (NJR) comparison of taper-slip and composite beam femoral stems. Acta Orthop 2019; 90:214–219 .
- 8.↑
Flatøy B , Röhrl SM , Rydinge J , Dahl J , Diep LM , Nordsletten L . Triple taper stem design shows promising fixation and bone remodelling characteristics: radiostereometric analysis in a randomised controlled trial. Bone Joint J 2015; 97-B:755–761 .
- 9.↑
National Joint Registry. National Joint Registry for England, Wales and Northern Ireland, 16th annual report, 2019. https://reports.njrcentre.org.uk/Portals/0/PDFdownloads/NJR%2016th%20Annual%20Report%202019.pdf (date last accessed 06 August 2020).
- 10.↑
Liberati A , Altman DG & Tetzlaff J et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration. BMJ 2009; 339:b2700 .
- 11.↑
Dawson J , Fitzpatrick R , Carr A , Murray D . Questionnaire on the perceptions of patients about total hip replacement. J Bone Joint Surg Br 1996; 78:185–190 .
- 12.↑
Harris WH . Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by Mold arthroplasty: an end-result study using a new method of result evaluation. J Bone Joint Surg Am 1969; 51:737–755 .
- 13.↑
Barrack RL , Mulroy RD Jr , Harris WH . Improved cementing techniques and femoral component loosening in young patients with hip arthroplasty: a 12-year radiographic review. J Bone Joint Surg Br 1992; 74:385–389 .
- 14.↑
National Heart, Lung and Blood Institute. Study quality assessment tools, 2018. https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools (date last accessed 06 August 2020 .
- 15.↑
Burston BJ , Barnett AJ , Amirfeyz R , Yates PJ , Bannister GC . Clinical and radiological results of the collarless polished tapered stem at 15 years follow-up. J Bone Joint Surg Br 2012; 94:889–894 .
- 16.↑
Weber E , Olsson C , Kesteris U , Flivik G . Is a hollow centralizer necessary when using a polished, tapered, cemented femoral stem? Acta Orthop 2017; 88:377–382 .
- 17.↑
Yates PJ , Burston BJ , Whitley E , Bannister GC . Collarless polished tapered stem: clinical and radiological results at a minimum of ten years’ follow-up. J Bone Joint Surg Br 2008; 90:16–22 .
- 18.↑
Yates P , Gobel D , Bannister G . Collarless polished tapered stem: clinical and radiological follow-up over 5 years. J Arthroplasty 2002; 17:189–195 .
- 19.↑
Jørgensen PB , Lamm M , Søballe K , Stilling M . Equivalent hip stem fixation by Hi-Fatigue G and Palacos R + G bone cement: a randomized radiostereometric controlled trial of 52 patients with 2 years’ follow-up. Acta Orthop 2019; 90:237–242 .
- 20.↑
Olerud F , Olsson C , Flivik G . Comparison of Refobacin bone cement and palacos with gentamicin in total hip arthroplasty: an RSA study with two years follow-up. Hip Int 2014; 24:56–62 .
- 21.↑
von Schewelov T , Carlsson A , Sanzén L , Besjakov J . 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. Bone Joint J 2014; 96-B:604–608 .
- 22.↑
Stefánsdóttir A , Franzén H , Johnsson R , Ornstein E , Sundberg M . Movement pattern of the Exeter femoral stem: a radiostereometric analysis of 22 primary hip arthroplasties followed for 5 years. Acta Orthop Scand 2004; 75:408–414 .
- 23.↑
Clement ND , Bardgett M & Merrie K et al. Cemented Exeter total hip arthroplasty with a 32 mm head on highly crosslinked polyethylene: does age influence functional outcome, satisfaction, activity, stem migration, and periprosthetic bone mineral density? Bone Joint Res 2019; 8:275–287 .
- 24.↑
Carrington NC , Sierra RJ , Gie GA , Hubble MJW , Timperley AJ , Howell JR . The Exeter Universal cemented femoral component at 15 to 17 years: an update on the first 325 hips. J Bone Joint Surg Br 2009; 91:730–737 .
- 25.↑
Hook S , Moulder E , Yates PJ , Burston BJ , Whitley E , Bannister GC . The Exeter Universal stem: a minimum ten-year review from an independent centre. J Bone Joint Surg Br 2006; 88:1584–1590 .
- 26.↑
Ek ET , Choong PFM . Comparison between triple-tapered and double-tapered cemented femoral stems in total hip arthroplasty: a prospective study comparing the C-Stem versus the Exeter Universal early results after 5 years of clinical experience. J Arthroplasty 2005; 20:94–100 .
- 27.↑
Lewthwaite SC , Squires B , Gie GA , Timperley AJ , Ling RS . The Exeter Universal hip in patients 50 years or younger at 10-17 years’ follow-up. Clin Orthop Relat Res 2008; 466:324 .
- 28.↑
Westerman RW , Whitehouse SL , Hubble MJW , Timperley AJ , Howell JR , Wilson MJ . The Exeter V40 cemented femoral component at a minimum 10-year follow-up: the first 540 cases. Bone Joint J 2018; 100-B:1002–1009 .
- 29.↑
Alfaro-Adrián J , Gill HS , Murray DW . Cement migration after THR: a comparison of Charnley elite and Exeter femoral stems using RSA. J Bone Joint Surg Br 1999; 81:130–134 .
- 30.↑
Glyn-Jones S , Gill HS , Beard DJ , McLardy-Smith P , Murray DW . Influence of stem geometry on the stability of polished tapered cemented femoral stems. J Bone Joint Surg Br 2005; 87:921–927 .
- 31.↑
Glyn-Jones S , Alfaro-Adrian J , Murray DW , Gill HS . The influence of surgical approach on cemented stem stability: an RSA study. Clin Orthop Relat Res 2006; 448:87–91 .
- 32.↑
Bohm E , Petrak M , Gascoyne T , Turgeon T . The effect of adding tobramycin to Simplex P cement on femoral stem micromotion as measured by radiostereometric analysis: a 2-year randomized controlled trial. Acta Orthop 2012; 83:115–120 .
- 33.↑
Park J-Y , Han H-J , Baik S-J , Kweon S-H . Long-term outcome of polished stems in total hip arthroplasty. Hip Pelvis 2015; 27:83–89 .
- 34.↑
Li MG , Rohrl SM , Wood DJ , Nivbrant B . Periprosthetic changes in bone mineral density in 5 stem designs 5 years after cemented total hip arthroplasty: no relation to stem migration. J Arthroplasty 2007; 22:689–691 .
- 35.↑
Glyn-Jones S , Hicks J , Alfaro-Adrian J , Gill HS , McLardy-Smith P , Murray DW . The influence of cement viscosity on the early migration of a tapered polished femoral stem. Int Orthop 2003; 27:362–365 .
- 36.↑
Kaneuji A , Sugimori T , Ichiseki T , Fukui K , Yamada K , Matsumoto T . The relationship between stem subsidence and improvement in the radiolucency in polished tapered stems. Int Orthop 2006; 30:387–390 .
- 37.↑
McCalden RW , Charron KD , Yuan X , Bourne RB , Naudie DD , MacDonald SJ . Randomised controlled trial comparing early migration of two collarless polished cemented stems using radiostereometric analysis. J Bone Joint Surg Br 2010; 92:935–940 .
- 38.↑
Murray DW , Gulati A , Gill HS . Ten-year RSA-measured migration of the Exeter femoral stem. Bone Joint J 2013; 95-B:605–608 .
- 39.↑
Nieuwenhuijse MJ , Valstar ER , Kaptein BL , Nelissen RGHH . The Exeter femoral stem continues to migrate during its first decade after implantation: 10-12 years of follow-up with radiostereometric analysis (RSA). Acta Orthop 2012; 83:129–134 .
- 40.↑
Nelissen RGHH , Garling EH , Valstar ER . Influence of cement viscosity and cement mantle thickness on migration of the Exeter total hip prosthesis. J Arthroplasty 2005; 20:521–528 .
- 41.↑
Madörin K , Siepen W , Manzoni I , Stoffel KK , Ilchmann T , Clauss M . Five-year prospective subsidence analysis of 100 cemented polished straight stems: a concise clinical and radiological follow-up observation. Orthop Rev (Pavia) 2019; 11:7984 .
- 42.↑
van der Voort P , Pijls BG & Nieuwenhuijse MJ et al. Early subsidence of shape-closed hip arthroplasty stems is associated with late revision: a systematic review and meta-analysis of 24 RSA studies and 56 survival studies. Acta Orthop 2015; 86:575–585 .
- 43.↑
Kobayashi S , Takaoka K , Saito N , Hisa K . Factors affecting aseptic failure of fixation after primary Charnley total hip arthroplasty: multivariate survival analysis. J Bone Joint Surg Am 1997; 79:1618–1627 .
- 44.↑
Teeter MG , McCalden RW , Yuan X , MacDonald SJ , Naudie DD . Predictive accuracy of RSA migration thresholds for cemented total hip arthroplasty stem designs. Hip Int 2018; 28:363–368 .
- 45.↑
Kärrholm J , Malchau H , Snorrason F , Herberts P . Micromotion of femoral stems in total hip arthroplasty: a randomized study of cemented, hydroxyapatite-coated, and porous-coated stems with roentgen stereophotogrammetric analysis. J Bone Joint Surg Am 1994; 76:1692–1705 .
- 46.↑
de Kam DCJ , Klarenbeek RLWA , Gardeniers JWM , Veth RP , Schreurs BW . The medium-term results of the cemented Exeter femoral component in patients under 40 years of age. J Bone Joint Surg Br 2008; 90:1417–1421 .
- 47.
Ling RSM , Charity J , Lee AJC , Whitehouse SL , Timperley AJ , Gie GA . The long-term results of the original Exeter polished cemented femoral component: a follow-up report. J Arthroplasty 2009; 24:511–517 .
- 48.↑
Schmitz MW , Bronsema E , de Kam DCJ , Gardeniers JWM , Veth RPH , Schreurs BW . Results of the cemented Exeter femoral component in patients under the age of 40: an update at ten to 20 years’ follow-up. Bone Joint J 2017; 99-B:192–198 .
- 49.↑
Purbach B , Kay PR , Siney PD , Fleming PA , Wroblewski BM . The C-stem in clinical practice: fifteen-year follow-up of a triple tapered polished cemented stem. J Arthroplasty 2013; 28:1367–1371 .
- 50.↑
Jayasuriya RL , Buckley SC , Hamer AJ , Kerry RM , Stockley I & Tomouk MW et al. Effect of sliding-taper compared with composite-beam cemented femoral prosthesis loading regime on proximal femoral bone remodeling: a randomized clinical trial. J Bone Jt Surg - Ser A 2013; 95:19–27 .
- 51.↑
Hauptfleisch J , Glyn-Jones S , Beard DJ , Gill HS , Murray DW . The premature failure of the Charnley Elite-Plus stem: a confirmation of RSA predictions. J Bone Joint Surg Br 2006; 88:179–183 .
- 52.↑
Van de , Groes S , Ypma J , Spierings P , Verdonschot N . Expectations and outcome of a scientifically developed hip prosthesis in 170 hips with a follow-up of 5-12 years. Acta Orthop Belg 2012; 78:628–636 .
- 53.↑
Nivbrant B , Kärrholm J , Söderlund P . Increased migration of the SHP prosthesis: radiostereometric comparison with the Lubinus SP2 design in 40 cases. Acta Orthop Scand 1999; 70:569–577 .
- 54.↑
Sundberg M , Besjakov J , von Schewelow T , Carlsson A . Movement patterns of the C-stem femoral component: an RSA study of 33 primary total hip arthroplasties followed for two years. J Bone Joint Surg Br 2005; 87:1352–1356 .
- 55.↑
Ilchmann T , Kesteris U , Wingstrand H . EBRA improves the accuracy of radiographic analysis of acetabular cup migration. Acta Orthop Scand 1998; 69:119–124 .
- 56.↑
Fowler JL , Gie GA , Lee AJ , Ling RS . Experience with the Exeter total hip replacement since 1970. Orthop Clin North Am 1988; 19:477–489 .
- 57.↑
Williams HDW , Browne G , Gie GA , Ling RSM , Timperley AJ , Wendover NA . The Exeter universal cemented femoral component at 8 to 12 years: a study of the first 325 hips. J Bone Joint Surg Br 2002; 84-B:324–334 .
- 58.↑
Young L , Duckett S , Dunn A . The use of the cemented Exeter Universal femoral stem in a district general hospital: a minimum ten-year follow-up. J Bone Joint Surg Br 2009; 91:170–175 .
- 59.↑
Maier MW , Streit MR & Innmann MM et al. Cortical hypertrophy with a short, curved uncemented hip stem does not have any clinical impact during early follow-up. BMC Musculoskelet Disord 2015; 16:371 .
- 60.
Iwase T , Morita D , Takemoto G . The effects of patient characteristics and stem alignment on distal femoral cortical hypertrophy after cemented polished tapered stem implantation. Eur J Orthop Surg Traumatol 2019; 30:559–567 .
- 61.↑
Katsimihas M , Katsimihas G , Lee MB , Learmonth ID . Distal femoral cortical hypertrophy: predisposing factors and their effect on clinical outcome. Hip Int 2006; 16:18–22 .
