Aims. The aim of this study was to radiologically evaluate the quality of cement mantle and alignment achieved with a polished tapered cemented femoral stem inserted through the anterior approach and compared with the posterior approach. Methods. A comparative retrospective study of 115 consecutive hybrid total hip arthroplasties or cemented hemiarthroplasties in 110 patients, performed through anterior (n = 58) or posterior approach (n = 57) using a collarless polished taper-slip femoral stem, was conducted. Cement mantle quality and thickness were assessed in both planes. Radiological outcomes were compared between groups. Results. No significant differences were identified between groups in Barrack grade on the anteroposterior (AP) (p = 0.640) or lateral views (p = 0.306), or for alignment on the AP (p = 0.603) or lateral views (p = 0.254). An adequate cement mantle (Barrack A or B) was achieved in 77.6% (anterior group, n = 45) and in 86% (posterior group, n = 49), respectively. Multivariate analysis revealed factors associated with unsatisfactory cement mantle (Barrack C or D) included higher BMI, left side, and Dorr Type C morphology. A mean cement mantle thickness of ≥ 2 mm was achieved in all Gruen zones for both approaches. The mean cement mantle was thicker in zone 7 (p < 0.001) and thinner in zone 9 for the anterior approach (p = 0.032). Incidence of cement mantle defects between groups was similar (6.9% (n = 4) vs 8.8% (n = 5), respectively; p = 0.489). Conclusion. An adequate cement mantle and good alignment can be achieved using a collarless polished tapered femoral component inserted through the anterior approach. Cite this article: Bone Joint J 2021;103-B(7 Supple B):46–52

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. Cite this article: Bone Joint J 2024;106-B(1):11–15

Aims. The Exeter V40 cemented femoral stem was first introduced in 2000. The largest single-centre analysis of this implant to date was published in 2018 by Westerman et al. Excellent results were reported at a minimum of ten years for the first 540 cases performed at the designer centre in the Exeter NHS Trust, with stem survivorship of 96.8%. The aim of this current study is to report long-term outcomes and survivorship for the Exeter V40 stem in a non-designer centre. Methods. All patients undergoing primary total hip arthroplasty using the Exeter V40 femoral stem between 1 January 2005 and 31 January 2010 were eligible for inclusion. Data were collected prospectively, with routine follow-up at six to 12 months, two years, five years, and ten years. Functional outcomes were assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. Outcome measures included data on all components in situ beyond ten years, death occurring within ten years with components in situ, and all-cause revision surgery. Results. A total of 829 stems in 745 patients were included in the dataset; 155 patients (20.8%) died within ten years, and of the remaining 664 stems, 648 stems (97.6%) remained in situ beyond ten years. For the 21 patients (2.5%) undergoing revision surgery, 16 femoral stems (1.9%) were revised and 18 acetabular components (2.2%) were revised. Indications for revision in order of decreasing frequency were infection (n = 6), pain (n = 6), aseptic component loosening (n = 3), periprosthetic fracture (n = 3), recurrent dislocation (n = 2), and noise production (ceramic-on-ceramic squeak) (n = 1). One patient was revised for aseptic stem loosening. The mean preoperative WOMAC score was 61 (SD 15.9) with a mean postoperative score of 20.4 (SD 19.3) (n = 732; 88.3%). Conclusion. The Exeter V40 cemented femoral stem demonstrates excellent functional outcomes and survival when used in a high volume non-designer centre. Outcomes are comparable to those of its serially validated predecessor, the Exeter Universal stem. Cite this article: Bone Jt Open 2020;1-12:743–748

Aims. Although CT is considered the benchmark to measure femoral version, 3D biplanar radiography (hipEOS) has recently emerged as a possible alternative with reduced exposure to ionizing radiation and shorter examination time. The aim of our study was to evaluate femoral stem version in postoperative total hip arthroplasty (THA) patients and compare the accuracy of hipEOS to CT. We hypothesize that there will be no significant difference in calculated femoral stem version measurements between the two imaging methods. Methods. In this study, 45 patients who underwent THA between February 2016 and February 2020 and had both a postoperative CT and EOS scan were included for evaluation. A fellowship-trained musculoskeletal radiologist and radiological technician measured femoral version for CT and 3D EOS, respectively. Comparison of values for each imaging modality were assessed for statistical significance. Results. Comparison of the mean postoperative femoral stem version measurements between CT and 3D hipEOS showed no significant difference (p = 0.862). In addition, the two version measurements were strongly correlated (r = 0.95; p < 0.001), and the mean paired difference in postoperative femoral version for CT scan and 3D biplanar radiography was -0.09° (95% confidence interval -1.09 to 0.91). Only three stem measurements (6.7%) were considered outliers with a > 5° difference. Conclusion. Our study supports the use of low-dose biplanar radiography for the postoperative assessment of femoral stem version after THA, demonstrating high correlation with CT. We found no significant difference for postoperative femoral version when comparing CT to 3D EOS. We believe 3D EOS is a reliable option to measure postoperative femoral version given its advantages of lower radiation dosage and shorter examination time. Cite this article: Bone Joint J 2022;104-B(11):1196–1201

Early micromotion of hip implants measured with radiostereometric analysis (RSA) is a predictor for late aseptic loosening. Computed Tomography Radiostereometric Analysis (CT-RSA) can be used to determine implant micro-movements using low-dose CT scans. CT-RSA enables a non-invasive measurement of implants. We evaluated the precision of CT-RSA in measuring early stem migration. Standard marker-based RSA was used as reference. We hypothesised that CT-RSA can be used as an alternative to RSA in assessing implant micromotions. We included 31 patients undergoing Total Hip Arthroplasty (THA). Distal femoral stem migration at 1 year was measured with both RSA and CT-RSA. Comparison of the two methods was performed with paired-analysis and Bland-Altman plots. Furthermore, the inter- and intraobserver reliability of the CT-RSA method was evaluated. No statistical difference was found between RSA and CTMA measurements. The Bland-Altman plots showed good agreement between marker-based RSA and CT-RSA. The intra- and interobserver reliability of the CT-RSA method was found to be excellent (≥0.992). CT-RSA is comparable to marker-based RSA in measuring distal femoral stem migration. CTMA can be used as an alternative method to detect early implant migration

The Accolade®TMZF is a taper-wedge cementless metaphyseal coated femoral stem widely utilized from 2002-2012. In recent years, there have been reports of early catastrophic failure of this implant. Establishing a deeper understanding of the rate and causes of revision in patients who developed aseptic failure in stems with documented concerns about high failure rates is critical. Understanding any potential patient or implant factors which are risk factors for failure is important to inform both clinicians and patients. We propose a study to establish the long-term survival of this stem and analyze patients who underwent aseptic revision to understand the causes and risk factors for failure. A retrospective review was undertaken of all patients who received a primary total hip arthroplasty with an Accolade® TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented and cross referenced with the Canadian Institute of Health Information Discharge Abstract Database to minimize loss to follow-up. Survivorship analysis was performed with use of the Kaplan-Meier curves to determine the overall and aseptic survival rates at final follow-up. Patient and implant factors commonly associated with aseptic failure were extracted and Cox proportional hazards model was used. A consecutive series of 2609 unilateral primary THA patients implanted with an Accolade®TMZF femoral hip stem were included. Mean time from primary surgery was 12.4 years (range 22 days to 19.5 years). Cumulative survival was 96.1% ± 0.2 at final follow-up. One hundred and seven patients underwent revision surgery with aseptic loosening of the femoral component was the most common cause of aseptic failure in this cohort (33/2609, 1.3%). Younger age and larger femoral head offset were independent risk factors for aseptic failure. To our knowledge, this is the largest series representing the longest follow-up of this taper-wedge cementless femoral implant. Despite early concerns, the Accolade® TMZF stem has excellent survivorship in this cohort. Trunnionosis as a recognized cause for revision surgery was rare. Younger age and larger femoral head offset were independent risk factors for aseptic failure

Aims. The direct anterior (DA) approach has been associated with rapid patient recovery after total hip arthroplasty (THA) but may be associated with more frequent femoral complications including implant loosening. The objective of this study was to determine whether the addition of a collar to the femoral stem affects implant migration, patient activity, and patient function following primary THA using the DA approach. Methods. Patients were randomized to either a collared (n = 23) or collarless (n = 26) cementless femoral stem implanted using the DA approach. Canal fill ratio (CFR) was measured on the first postoperative radiographs. Patients underwent a supine radiostereometric analysis (RSA) exam postoperatively on the day of surgery and at two, four, six, 12, 26, and 52 weeks postoperatively. Patient-reported outcome measures (Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index, the 12-item Short Form Health Survey Mental and Physical Score, and University of California, Los Angeles (UCLA) Activity Score) were measured preoperatively and at each post-surgery clinic visit. Activity and function were also measured as the weekly average step count recorded by an activity tracker, and an instrumented timed up-and-go (TUG) test in clinic, respectively. Results. Comparing the RSA between the day of surgery baseline exam to two weeks postoperatively, subsidence was significantly lower (mean difference 2.23 mm (SD 0.71), p = 0.023) with collared stems, though these patients had a greater CFR (p = 0.048). There was no difference (p = 0.426) in subsidence between stems from a two-week baseline through to one year postoperatively. There were no clinically relevant differences in PROMs; and there was no difference in the change in activity (p = 0.078) or the change in functional capacity (p = 0.664) between the collared stem group and the collarless stem group at any timepoint. Conclusion. Presence of a collar on the femoral stem resulted in reduced subsidence during the first two postoperative weeks following primary THA using the DA approach. However, the clinical implications are unclear, and larger studies examining patient activity and outcomes are required. Cite this article: Bone Joint J 2020;102-B(12):1654–1661

INTRODUCTION. Short femoral stem use in total hip arthroplasty (THA) has increased due to positive short-term clinical and biomechanical success. A neck preserving femoral stem not only preserves proximal bone volume, but preserves the high quality bone of the medial neck. The short stem design allows for less invasive surgical exposure and less invasive violation of the femoral canal (Figure 1). Additionally, it facilitates future revision THA, if needed, with a conventional primary stem. The objective of this study was to evaluate the early clinical outcomes of the Alteon® Neck Preserving Femoral Stem (Exactech, Inc.). METHODS. Forty-nine subjects (25 males, 24 females; mean age: 58.3±7.6 years; mean BMI: 29.8±5.6) from 2 sites underwent primary THA with the Alteon Neck Preserving Femoral Stem. All participants signed the informed consent, and both sites received IRB approval prior to conducting the study. Clinical data outcomes for this study included the Harris Hip Score (HHS), the Oxford Hip Score (OHS), revisions, and subsidence at 3-month, 1-year, and 2-year post-operative time points. Subsidence was measured by an independent third party. Student t-tests were used to identify significant mean differences between genders (p<0.05). RESULTS. The means and standard deviations for the HHS and OHS are shown in Figures 2 and 3 respectively. For patients reaching the 2-year post-operative time point (n=28), the HHS improved by 51.3 points to 96.1 from 44.8 and the OHS improved by 23.0 points to 43.8 from 20.8. There was no significant difference between genders with regard to BMI or post-operative HHS or OHS scores. However, the females were significantly older (61.4 vs. 55.3) and had a significantly lower pre-operative HHS (44.3 vs. 53.5). There were 2 revisions reported, and there was one report of subsidence at 1 year (n=33); zero reports of subsidence at 2 years (n=24). DISCUSSION. The neck preserving femoral stem exhibited positive early clinical results as demonstrated by the marked improvement in functional outcome scores from the pre-operative visit to 2-years post-operative. These 2-year improvements are better than moderate clinically important improvements reported in the literature (40.1 points for HHS). Functional outcomes scores kept improving at the 3-month, 1-year, and 2-year post-operative visits. Additional 2-year outcomes data will be incorporated into this dataset as they become available. For the two revisions, one was due to a calcar fracture and one was due to a patient fall. The patient who fell reported weight-bearing pain after the fall at the 1-year post-operative visit and was subsequently revised. Stem movement was documented as a result of the fall; this was the only report of subsidence. SIGNIFICANCE. The neck preserving femoral stem evaluated in this study demonstrated positive early clinical performance with no reports of subsidence (except for one case that was revised due to a fall). This neck preserving stem design is a promising alternative to conventional femoral stems. For any figures or tables, please contact authors directly

Aims. The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems. Methods. A systematic literature search was performed adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. In parallel, we performed a retrospective single centre study of Exeter V40 femoral stem prosthetic fractures between April 2003 and June 2020. Results. There are 25 reported cases of such prosthetic fractures confined to small case series and case reports within the literature. We report an additional 19 cases to the literature (mean age 66.3 years (SD 11.7); 12 (63%) females; BMI 32.9 kg/m. 2. (SD 5.9)). The mean time from index procedure to fracture was 7.8 years (SD 3.6; 2.5 to 16.3). Exeter V40 stem fracture incidence was 0.15% and 1.21% for primary and revision arthroplasty, respectively. Incidence was significantly higher in revision arthroplasty (p < 0.001) and 125 mm length stems compared to ≥ 150 mm length stems (1.25% vs 0.13%, respectively; p < 0.001). When comparing different stem length cohorts, 125 mm short-stems were associated with stem-body fractures (92% vs 29%; p = 0.0095), earlier time to fracture (6.2 years vs 11.0 years; p = 0.0018), younger patient age at time of fracture (62.7 years vs 72.6 years; p = 0.037), and female sex (75% vs 43%; p = 0.326). Conclusion. This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. Short 125 mm length Exeter V40 stems undoubtedly have a role in restoring anatomy and biomechanics in smaller femoral geometries, although the surgeon has to appreciate the higher risk of stem fracture and the associated predisposing factors which may necessitate particular attention to surgical technique and planning. Cite this article: Bone Jt Open 2021;2(6):443–456

Purpose. Short metaphyseal fitting femoral stems convey stress to proximal femur and have no distal fixation. They have advantages in that there is no thigh pain and no bone loss due to stress shielding, but there is a concern for weakened fixation. So the authors evaluated whether short metaphyseal fitting femoral stems, which have only metaphyseal and no diaphyseal fixation, can acquire sufficient stability. Materials & methods. 39 cases of 36 patients who undervent uncemented total hip arthroplasty with DePuy Proxima. TM. (Johnson & Johnson orthopaedics, New Milton, UK) short metaphyseal fitting femoral stems from August 2009 to September 2011 were retrospectively evaluated. There were 19 male and 20 female cases. The mean follow-up period was 35.8(21.8∼49.2) months. Harris hip scores, WOMAC scores, UCLA scores, and presence of femoral pain were evaluated to assess clinical outcome. Femoral radiolucency in coronal and sagittal views of the hip, femoral stem loosening, and displacement was measured to evaluate radiological outcome. Distance between femoral stem and cortical bone was also measured to assess the relationship with radiolucency and loosening according to degree of contact. Results. Harris hip score before and after operation was 49.8(37–59) and 96.0(71–100) on average. WOMAC score improved from 44.1(31.9–56.3) to 91.8(62.3–100)after operation. UCLA activity score improved from 3.8(2–5) to 7.5(4–9) after operation. When assessed with 1mm as the standard, radiolucent line was shown in 5 cases(12.8%). When the area around the stem was divided into 5 sections, there were 3 cases in which radiolucent line was observed in all 5 sections, 1 case in which radiolucent line was found in only section 4, and 1 case in which radiolucent line was found only in section 5. There was 1 case(2.6%) that required revision THA due to femoral stem loosening. Femoral radiolucency and loosening on coronal and sagittal views increased with greater distance between femoral stem and cortical bone (p=0.002). Conclusion. In uncemented total hip arthroplasty with short metaphyseal fitting femoral stem, it is important to fill the femoral metaphyseal medullary cavity completely with the femoral stem. Therefore, there is severe loss of cancellous bone at proximal femur. Stability varies with differing degree of contact between femoral stem and proximal femoral cortical bone observed on postoperative coronal and sagittal views. When short metaphyseal fitting femoral stems are used, adequate early fixation can be achieved only with understanding of such characteristics as well as sufficient proficiency of the operator

Aims. The aim of this study was to compare the design of the generic OptiStem XTR femoral stem with the established Exeter femoral stem. Materials and Methods. We obtained five boxed, as manufactured, implants of both designs at random (ten in total). Two examiners were blinded to the implant design and independently measured the mass, volume, trunnion surface topography, trunnion roughness, trunnion cone angle, Caput-Collum-Diaphyseal (CCD) angle, femoral offset, stem length, neck length, and the width and roughness of the polished stem shaft using peer-reviewed methods. We then compared the stems using these parameters. Results. We found that the OptiStems were lighter (p < 0.001), had a rougher trunnion surface (p <  0.001) with a greater spacing and depth of the machined threads (p < 0.001), had greater trunnion cone angles (p = 0.007), and a smaller radius at the top of the trunnion (p = 0.007). There was no difference in stem volume (p = 0.643), CCD angle (p = 0.788), offset (p = 0.993), neck length (p = 0.344), stem length (p = 0.808), shaft width (p = 0.058 to 0.720) or roughness of the polished surface (p = 0.536). Conclusion. This preliminary investigation found that whilst there were similarities between the two designs, the generic OptiStem is different to the branded Exeter design. Cite this article: Bone Joint J 2017;99-B:310–16

Aims. Femoral stems with exchangeable (modular) necks were introduced to offer surgeons an increased choice when determining the version, offset and length of the femoral neck during total hip arthroplasty (THA). It was hoped that this would improve outcomes and reduce complications, particularly dislocation. In 2010, the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) first reported an increased rate of revision after primary THA using femoral stems with an exchangeable neck. The aim of this study was to provide a more comprehensive up-to-date analysis of primary THA using femoral stems with exchangeable and fixed necks. Materials and Methods. The data included all primary THA procedures performed for osteoarthritis (OA), reported to the AOANJRR between 01 September 1999 and 31 December 2014. There were 9289 femoral stems with an exchangeable neck and 253 165 femoral stems with a fixed neck. The characteristics of the patients and prostheses including the bearing surface and stem/neck metal combinations were examined using Cox proportional hazard ratios (HRs) and Kaplan-Meier estimates of survivorship. . Results. It was found that prostheses with an exchangeable neck had a higher rate of revision and this was evident regardless of the bearing surface or the size of the femoral head. Exchangeable neck prostheses with a titanium stem and a cobalt-chromium neck had a significantly higher rate of revision compared with titanium stem/titanium neck combinations (HR 1.83, 95% confidence interval 1.49 to 2.23, p < 0.001). Revisions were higher for these combinations compared with femoral stems with a fixed neck. Conclusion . There appears to be little evidence to support the continued use of prostheses with an exchangeable neck in primary THA undertaken for OA. Cite this article: Bone Joint J 2017;99-B:766–73

Following the recall of modular neck hip stems in July 2012, research into femoral modularity will intensify over the next few years. This review aims to provide surgeons with an up-to-date summary of the clinically relevant evidence. The development of femoral modularity, and a classification system, is described. The theoretical rationale for modularity is summarised and the clinical outcomes are explored. The review also examines the clinically relevant problems reported following the use of femoral stems with a modular neck. Joint replacement registries in the United Kingdom and Australia have provided data on the failure rates of modular devices but cannot identify the mechanism of failure. This information is needed to determine whether modular neck femoral stems will be used in the future, and how we should monitor patients who already have them implanted. Cite this article: Bone Joint J 2013;95-B:1011–21

Background. Short bone-conserving femoral stem implants were developed to achieve more physiological, proximal bone loading than conventional femoral stems. Concerns have arisen, however, that improved loading may be offset by lower primary stability because of the reduced potential area for bony contact. Aims. The aim of this study was to determine the primary stability of a novel short femoral stem compared with a conventional femoral stem following cementless total hip arthroplasty (THA), in a prospective, blinded, randomised, controlled trial using radiostereometric analysis. Methods. Fifty-three patients were randomised to receive cementless THA with either a short femoral stem or a conventional femoral stem. The CONSORT diagram is shown (Figure I). Surgery was performed at one institution by three surgeons. 26 patients received the short stem and 23 received the conventional stem. Complete follow-up was available on 40 patients (82%). All patients received the same cementless acetabular component. The primary outcomes were dynamically inducible micromotion and migration of the femoral stems at two years. Both were measured using radiostereometric analysis. Radiographs for radiostereometric analysis were taken post-operatively and at three, six, 12, 18 and 24 months. Validated geometric algorithms were used to determine the relative three-dimensional position of the prosthetic stem and host bone. Results. At two years, there was significantly less subsidence (inferior migration) of the short femoral stem (head: 0.28mm; 95% confidence interval [CI] +/−0.17; SD 0.38; tip: 0.10mm; 95% CI +/− 0.18; SD 0.41) compared with the conventional stem (head: 0.61mm, 95% CI +/−0.26, SD 0.55, P=0.03; tip: 0.44mm, 95% CI +/−0.21, SD 0.43, P=0.02) (Figure II). There was no significant difference in dynamically inducible micromotion. Conclusion. This study demonstrates that the short femoral stem has a stable and predictable migration. However, longer-term survival analysis remains important. For any figures and tables, please contact the authors directly

Fixation of cemented femoral stems is reproducible and provides excellent early recovery of hip function in patients 60–80 years old. The durability of fixation has been evaluated up to 20 years with 90% survivorship. The mode of failure of fixation of cemented total hip arthroplasty is multi-factorial; however, good cementing techniques and reduction of polyethylene wear have been shown to reduce its incidence. The importance of surface roughness for durability of fixation is controversial. This presentation will describe my personal experience with the cemented femoral stem over 30 years with 3 designs and surface roughness (RA) ranging from 30–150 microinches. RESULTS. Since 1978, three series of cemented THA have been prospectively followed using periodic clinical and radiographic evaluations. All procedures were performed by the author using the posterior approach. Excellent results and Kaplan-Meier survivorship ranged from 90–99.5% in the best case scenario were noted at 10–20-year follow-up. CONCLUSION. With a properly-designed femoral stem, good cement technique, proper cement mantle, and surface roughness of 30–40 microinches, the cemented femoral stem provides a durable hip replacement in patients 60–80 years old with up to 95% survivorship at 10–20-year follow-up

Aims. Highly polished stems with force-closed design have shown satisfactory clinical results despite being related to relatively high early migration. It has been suggested that the minimal thickness of cement mantles surrounding the femoral stem should be 2 mm to 4 mm to avoid aseptic loosening. The line-to-line cementing technique of the femoral stem, designed to achieve stem press-fit, challenges this opinion. We compared the migration of a highly polished stem with force-closed design by standard and line-to-line cementing to investigate whether differences in early migration of the stems occur in a clinical study. Methods. In this single-blind, randomized controlled, clinical radiostereometric analysis (RSA) study, the migration pattern of the cemented Corail hip stem was compared between line-to-line and standard cementing in 48 arthroplasties. The primary outcome measure was femoral stem migration in terms of rotation and translation around and along with the X-, Y-, and Z- axes measured using model-based RSA at three, 12, and 24 months. A linear mixed-effects model was used for statistical analysis. Results. Results from mixed model analyses revealed a lower mean retroversion for line-to-line (0.72° (95% confidence interval (CI) 0.38° to 1.07°; p < 0.001), but no significant differences in subsidence between the techniques (-0.15 mm (95% CI -0.53 to 0.227; p = 0.429) at 24 months. Radiolucent lines measuring < 2 mm wide were found in three and five arthroplasties cemented by the standard and line-to-line method, respectively. Conclusion. The cemented Corail stem with a force-closed design seems to settle earlier and better with the line-to-line cementing method, although for subsidence the difference was not significant. However, the lower rate of migration into retroversion may reduce the wear and cement deformation, contributing to good long-term fixation and implant survival. Cite this article: Bone Joint J 2022;104-B(1):19–26

Purpose. The purpose of this study was to evaluate and compare the clinical, radiological outcomes of the group of patients with distal femoral cortical hypertrophy (DFCH) and without DFCH after hip arthroplasty using a cementless double tapered femoral stem and to analyze a correlation between patients factors and DFCH. Materials and Methods. Four hundreds four patients (437 hips) who underwent total hip arthroplasty (n = 293) or hemiarthroplasty (n = 144) using a Accolade TMZF femoral stem between Jun 2006 and March 2012 and were follow up period more than 24 months after surgery were enrolled in this study. They were divided into 2 groups, the one group (n = 27) included patients with DFCH, and the other group (n = 410) included patients without DFCH. The mean follow up period was 54.5 months (range, 24 to 85 months) and 56.2 months (range, 24 to 92 months) for patients with DFCH and without DFCH. Results. The mean HHS, VAS signiï¬cantly improved from 61.4 and 5.5 preoperatively to 95.9 and 1.0 at the ï¬nal follow-up, respectively (P< .001), in the DFCH group and from 57.8 and 4.5 to 91.6 and 0.6 respectively (P< .001), in the control group. There were no signiï¬cant differences between the 2 groups (P> .05). Incidence of the thigh pain in the DFCH group (18.5%) was significantly higher than the control group (2.2%) (P< .001). The mean canal flare index (CFI) and subsidence was 3.71 (range, 2.61 to 5.78) and 1.5 mm (range, 0.1 to 6.1mm) for the DFCH group, 3.30 (range, 1.31 to 5.61) and 3.4 mm (range, 0.33 to 14.9 mm) for the control group. There were significantly differences between 2 groups (p< .002, < .001). The DFCH was significantly correlated with thigh pain and subsidence (p= .001; OR, 11.194; CI, 3.434 to 36.498 for thigh pain, p= .001; OR, 0.080; CI, 0.032 to 0.198 for subsidence), but not with sex. The incidence of DFCH increased significantly with increasing CFI and decreasing age (P= .043; OR, 1.828; CI, 1.018 to 3.280 for CFI; P= .015; OR, 0.968; CI, 0.944 to 0.994 for age). All the femoral stems showed stable fixation and there was no osteolysis or loosening. Conclusion. The DFCH occurs in 6.2% after hip arthroplasties using a double tapered femoral stem. The DFCH group showed less incidence of vertical subsidence, more younger and larger CFI. Difficult over tight placement of femoral stem to the distal femur results on DFCH, as well as thigh pain in some cases. However, there was no influence on clinical outcomes and femoral stem instability, bony fixation

As an increasing number of young, active, large patients are becoming candidates for total hip replacements, there is an increasingly urgent need to identify arthroplasties that will be durable, highly functional and amenable to possible future successful revision. In an era when cemented femoral stems were the primary implant option, the concept of a surface replacement was attractive and, perhaps, appropriate. However, cementless femoral stems of many designs now provide dependable long-term fixation and excellent, near normal function in patients of all ages, sex and level of activity. However, a number of issues related to cementless stem fixation could be further improved: Optimization of load transfer to proximal femur to minimise fracture risk and maximise bone preservation; Elimination of proximal-distal mismatch concerns, including bowed femurs; Facilitation of femoral stem insertion, especially with MIS THA exposures; Facilitation of revision with implants capable of providing durable fixation for active patients. The potential benefits of short stem femoral THA implants include: Ease of insertion; Reproducibility of insertion; Avoidance of issues related to proximal-distal anatomic mismatch or variations in proximal femoral diaphyseal anatomy (e.g. femoral bowing); Facilitation of MIS surgical approaches, especially anterior exposures; Optimization of proximal femoral load transfer with consequent maximization of proximal bone preservation. The purpose of this presentation is to describe the design rationale and characteristics of short (< 115 mm) uncemented primary THA femoral stem, to evaluate the clinical and radiographic results of short stems and to discuss the possible drawbacks specific to the use of short stems

Background. Safety and efficacy of novel prostheses relies on the determination of early implant migration and subsequent risk of loosening. Radiostereometric Analysis (RSA) has been used to evaluate the clinical failure risks of femoral stems by reporting distal migration, a measure of stem subsidence, when examining early migration characteristics. The migratory patterns of femoral stems, 24 months postoperatively, have provided a surrogate outcome measure to determine implant stabilisation and predict long-term performance and survivorship. RSA assessed femoral stem migration and provided comparison of the early migration characteristics with published data of a clinically established counterpart. Methods. Twenty five patients undergoing primary total hip arthroplasty were implanted with a hydroxyapatite-coated femoral stem. The median age was 65 years (range, 43–75 years). During surgery tantalum markers were attached onto the distal tip and shoulder of the stem. Eight tantalum markers were inserted into the femur, four placed in each of the greater and lesser trochanter. RSA examinations were performed postoperatively at 4 to 5 days, 6, 12 and 24 months. Eleven patients who had complete RSA follow-up as well as the valid data from five patients were analysed to determine the movement of the femoral stem relative to the femur and were compared to the published data of a clinically established counterpart. Results. At 24 months the magnitude of migration of the femoral stem translations for the y axis of movement was 0.32 mm (range, 0.00 to 2.04 mm) (Figure 1). The data demonstrates that this migration of the femoral stem occurred primarily in the first 6 months postoperatively and that the migration characteristics exhibit a pattern of implant stabilisation between 6 and 24 months. At 24 months the magnitude of migration of the femoral stem rotations for the longitudinal y axis of movement was 0.60. o. (range, 0.08 to 2.08. o. ). The data demonstrates continuing migration of the femoral stem at 12 months postoperatively with early indications of implant stabilisation between 12 and 24 months. At 24 months the mean subsidence/distal migration of the femoral stem was 0.20 mm (range, −2.04 to 0.32 mm) (Figure 2). At 6 months, two patients (12.5%) exhibited subsidence greater than 0.50 mm with one demonstrating a mean subsidence of 2.00 mm. Between 6 and 24 months these two patients exhibited no more than 0.04 mm of subsidence (Figure 3). The mean retroversion rotation of the stem was 0.10. o. (range, −0.99 to 2.08. o. ). One patient rotated more than 2.00. o. into retroversion at 12 and 24 months postoperatively. Conclusions. In comparison the data demonstrates less stem subsidence and retroversion rotation than published data for a cementless hydroxyapatite-coated femoral stem when observing early migration characteristics. The magnitude and pattern of migration exhibited is indicative of good clinical outcomes and is comparable with a clinically established counterpart after short-term follow-up with RSA. These findings and comparisons highlight the early migration characteristics of a hydroxyapatite-coated femoral stem, however the analysis and comparison of the migratory pattern and characteristics over the mid-term follow-up will confirm implant stabilisation

Aims. Compared with primary total hip arthroplasty (THA), revision surgery can be challenging. The cement-in-cement femoral revision technique involves removing a femoral component from a well-fixed femoral cement mantle and cementing a new stem into the original mantle. This technique is widely used and when carried out for the correct indications, is fast, relatively inexpensive and carries a reduced short-term risk for the patient compared with the alternative of removing well-fixed cement. We report the outcomes of this procedure when two commonly used femoral stems are used. Patients and Methods. We identified 1179 cement-in-cement stem revisions involving an Exeter or a Lubinus stem reported to the Swedish Hip Arthroplasty Register (SHAR) between January 1999 and December 2015. Kaplan-Meier survival analysis was performed. Results. Survivorship is reported up to six years and was better in the Exeter group (91% standard deviation (. sd). 2.8% versus 85% . sd. 5.0%) (p = 0.02). There was, however, no significant difference in the survival of the stem and risk of re-revision for any reason (p = 0.58) and for aseptic loosening (p = 0.97), between revisions in which the Exeter stem (94% . sd. 2.2%; 98% . sd. 1.6%) was used compared with those in which the Lubinus stem (95% . sd. 3.2%; 98% . sd.  2.2%) was used. The database did not allow identification of whether a further revision was indicated for loosening of the acetabular or femoral component or both. Conclusion. The cement-in-cement technique for revision of the femoral component gave promising results using both designs of stem, six years post-operatively. Cite this article: Bone Joint J 2017;99-B(4 Supple B):27–32

Background. It is known that excessive varus alignment of the femoral stem in total hip replacement (THR) creates a sub-optimal biomechanical environment which is associated with increased rates of revision surgery and component wear. Little is known regarding the effect of femoral stem alignment on patient functional outcome. Methods. A retrospective study of patients undergoing primary THR at the RNOH. Alignment of the femoral stem component in-situ was measured subjectively by a consultant musculoskeletal radiologist in both coronal and sagittal planes using post-operative anterior-posterior and lateral pelvic radiographs. Each THR was grouped into valgus, minor-valgus, neutral, minor-varus or varus coronal plane alignment and posterior, minor-posterior, neutral, minor-anterior or anterior sagittal plane alignment. Patient reported functional outcome was assessed by Oxford Hip Score (OHS) and WOMAC questionnaires after a minimum follow-up of 11 months. Maximum range of passive hip flexion, abduction, adduction, external and internal rotation were measured in clinic. A factorial linear regression model was used to analyse data. Results. 90 THRs were studied in 87 patients (55 Female). Mean age at THR=62 (22–86). Mean follow-up 17 months (11–39 months). Median OHS = 16, WOMAC = 8. Coronal plane alignment of the femoral stem was not associated with any significant change in OHS, WOMAC score or hip range of motion in any direction (all p>0.05). Sagittal plane alignment of the femoral stem was not associated with any significant change in OHS, WOMAC score or hip range of motion in any direction (all p >0.05). Conclusion. Although it is known that alignment of the femoral stem in sagittal and coronal planes has a direct effect on survivorship of the prosthesis, our study does not demonstrate any relationship between femoral stem alignment and functional outcome in patients undergoing primary THR

The removal of well-fixed bone cement from the femoral canal during revision of a total hip replacement (THR) can be difficult and risks the loss of excessive bone stock and perforation or fracture of the femoral shaft. Retaining the cement mantle is attractive, yet the technique of cement-in-cement revision is not widely practised. We have used this procedure at our hospital since 1989. The stems were removed to gain a better exposure for acetabular revision, to alter version or leg length, or for component incompatibility. We studied 136 hips in 134 patients and followed them up for a mean of eight years (5 to 15). A further revision was required in 35 hips (25.7%), for acetabular loosening in 26 (19.1%), sepsis in four, instability in three, femoral fracture in one and stem fracture in one. No femoral stem needed to be re-revised for aseptic loosening. A cement-in-cement revision of the femoral stem is a reliable technique in the medium term. It also reduces the risk of perforation or fracture of the femoral shaft

Aims. This study reports the results of 38 total hip arthroplasties (THAs) in 33 patients aged less than 50 years, using the JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component. Methods. We describe the survival, radiological, and functional outcomes of 33 patients (38 THAs) at a mean follow-up of 27 years (25 to 32) between 1988 and 2018. Results. Of the surviving 30 patients (34 THAs), there were four periprosthetic fractures: one underwent femoral revision after 21 years, two had surgical fixation as the stem was deemed stable, and one was treated nonoperatively due to the patient’s comorbidities. The periprosthetic fracture patients showed radiological evidence of change in bone stock around the femoral stem, which may have contributed to the fractures; this was reflected in change of the canal flare index at the proximal femur. Two patients (two hips) were lost to follow-up. Using aseptic loosening as the endpoint, 16 patients (18 hips; 48%) needed acetabular revision. None of the femoral components were revised for aseptic loosening, demonstrating 100% survival. The estimate of the cumulative proportion surviving for revisions due to any cause was 0.97 (standard error 0.03). Conclusion. In young patients with high demands, the Furlong HAC-coated femoral component gives excellent long-term results. Cite this article: Bone Jt Open 2024;5(4):286–293

Aims: The bone – conductive proparties of hydroxyapatite (HA) coatings are attractive in revision surgery with bone loss. The purpose of this study is to analyse the clinical and radiological results of 55 cases of revision hip arthroplasty using hydroxyapatite femoral stems. Methods: Between May 1995 and October 2000 we performed 55 patients total hip replacements in 50 patients (5 bilateral) using hydroxyapatite (HA) – coated femoral stem. The average age of the patients at the time of the index revision was 67 years (range 44–84). Clinical evaluation was by a Merle d’Aubigne Score (preoperative 6.54 points). Radiological evaluation used the AAOS system for preoperative films and scaring system after Engh for the postoperative films. Bone grafts was required in 35 cases. Results: Postoperative Merle d’Aubigne score was 17.25 points. Complications: 3 dislocations, one transitory nerve palsy and 14 associated intraoperative fractures. All grafts consolidated. None of the femoral stem components required revision because of aseptic loosening. No radiologically progressive lucency or signs indicating a loose implant were visible in anycases. There were no cases of femoral stem migration. Conclusions: We conclude that the hydroxyapatite femoral stem is suitable for implantation at revision hip arthroplasty and can give good results in the short to medium term, because the clinical and radilogical results are excellent, with a early consolidate fractures

The Lubinus SP II is an anatomical femoral stem with high survivorship levels notably described in the Swedish Arthroplasty Register. As the clinical and economic burden of revision total hip arthroplasty (THA) and periprosthetic fracture (PPF) continues to increase, it has been suggested that use of anatomical stems may facilitate more uniform cement mantles and improve implant survival. The primary aim of this study was to determine the long-term survivorship and PPF rate of the Lubinus SP II 150mm stem in a single UK centre. Between January 2007 and April 2012, 1000 consecutive THAs were performed using the Lubinus SP II femoral stem in our institution. Patient demographics and operative details were collected in a prospective arthroplasty database. Patient records and national radiographic archives were then reviewed at a mean of 12.3 years (SD 1.3) following surgery to identify occurrence of subsequent revision surgery, dislocation or periprosthetic fracture. Mean patient age at surgery was 69.3 years (SD 10.1, 24–93 years). There were 634 women (63%). Osteoarthritis was the operative indication in 974 patients (97%). There were 13 revisions in total (4 for recurrent dislocation, 3 for infection, 6 for acetabular loosening) and 16 dislocations (1.6%). Stem survivorship at 10 years was 99.6% (95 % confidence interval [CI], 99.5%–99.7%) and at 15 years was 98.8% (98.7%–98.9%). The 15-year stem survival for aseptic loosening was 100%. Analysis of all cause THA failure demonstrated a survivorship of 99.1% (99.0%–99.3%) at 10 years and 98.2% (98.1%–98.3%) at 15 years. There were 4 periprosthetic fractures in total (0.4%) at mean 12.3 year follow-up. The Lubinus SP II stem demonstrated excellent survivorship, low dislocation rates and negligible PPF rates up to 15 years following primary THA. Use of anatomical stems such as the Lubinus SPII would appear to be a wise clinical and economic investment for patients and healthcare systems alike

It is known that excessive varus alignment of the femoral stem in total hip replacement (THR) creates a sub-optimal biomechanical environment which is associated with increased rates of revision surgery and component wear. Little is known regarding the effect of femoral stem alignment on patient functional outcome. Methods. Retrospective study of primary THR patients at the RNOH. Alignment of the femoral stem component in-situ was measured subjectively by a consultant musculoskeletal radiologist in both coronal and sagittal planes using post-operative anterior-posterior and lateral pelvic radiographs. Each THR was grouped into valgus, minor-valgus, neutral, minor-varus or varus coronal plane alignment and posterior, minor-posterior, neutral, minor-anterior or anterior sagittal plane alignment. Patient reported functional outcome was assessed by Oxford Hip Score (OHS) and WOMAC questionnaires. Data analysed using a linear regression model. Results. 90 THRs were studied in 87 patients (55 Female). Mean age at THR=62 (22-86). Mean follow-up=17 months (11-39 months). Median OHS=16, WOMAC=8. Coronal plane alignment of the femoral stem was not associated with any change in OHS (p>0.05) or WOMAC score (p>0.05). Sagittal plane alignment of the femoral stem was not associated with any change in OHS (p>0.05) or WOMAC score (p>0.05). Conclusion. Although it is known that alignment of the femoral stem on sagittal and coronal planes has a direct effect on survivorship of the prosthesis, our study does not demonstrate any relationship between femoral stem alignment and functional outcome in patients undergoing primary THR

We report the results of the Charnley Elite Plus femoral stem (Ortron 90; Depuy, Leeds, United Kingdom) in multiple surgeon’s hands at a minimum of three years post implantation. The long term results of the Charnley femoral stem have been widely documented . There have been numerous changes to the design and instrumentation of this original stem since its introduction in 1962, and the Charnley Elite Plus represents the fifth generation of this highly successful implant. Between March 1994 and March 1998, 244 patients underwent 268 primary hip arthroplasty procedures using this particular stem. Patients were reviewed at a mean of 4.5 years (3.0 – 6.8 years) following their arthroplasty using the Oxford Hip Score and plain radiographs. There were five revision procedures for aseptic loosening (5/268; 1.9%). Radiological assessment revealed gross radiological failure in a further 12 femoral stems (12/208; 5.8%). There was evidence of focal osteolysis with an apparently stable implant in 36 hips (17.3%). In the best case scenario, using revision for aseptic loosening as the endpoint, the survivorship for this period is 98.1%. If radiographic failures are incorporated into this endpoint, survivorship is 93.1%. Of potential concern however, is the number of adverse features noted on the radiographs, with only 76.9% being categorised as ‘normal.’. The Charnley Elite Plus stem has undergone some fundamental design changes from the original Charnley stem and therefore clinical success should not be automatically assumed. In such circumstances we recommend regular clinical and radiographic follow-up of patients who have have undergone total hip arthroplasty with this particular femoral stem

INTRODUCTION:. Modular femoral stems of Total Hip Arthroplasty (THA) have been designed to fit the metaphysis and diaphysis separately. Clinical results with modular femoral stems are reported to be satisfactory, but there exists several concerns with modular implant connections, including fretting corrosion, fracture of implant, and dissociation the stem from the proximal sleeve. Recently, we have become aware of another potential consequence of the modular design: sleeve deformation secondary to forces encountered during insertion. In our patients, we noted that the stems would not fully seat in the machined taper of the sleeve, indicating that some type deformation to the sleeve had occurred. We began an in vivo study to characterize this phenomenon. The objectives of this study were (1) Does deformation occur by impacting the sleeve into the metaphysis? (2) If so, quantify the sleeve deformation in hip arthroplasty patients. MATERIALS AND METHODS:. One man and 7 women undergoing primary THA were enrolled. This project was approved by IRB. This modular system (4-U CLS; Nakashima Medical Co., Japan) consists of a metaphyseal sleeve that connects with the diaphyseal stem via a Morse taper. The sleeve was impacted into the metaphysis first, followed by the stem. A custom taper gauge for each size of sleeve (Figure 1A) was inserted into the sleeve before and after impacting the sleeve into the metaphysis, and the distance between the top of the sleeve and the top of the gauge was measured using a caliper (* in Figure 1B). Deformation was defined as the difference in distance between the before and the after impacted dimensions. Preoperative femoral morphology, assessed using Dorr classification system, was type A in 2 hips, type B in 5 hips, and type C in 1 hip. RESULTS:. Intraoperatively, all sleeves had measurable deformity. Deformation ranged from 0.1 to 3.2 mm and averaged 1.18 ± 1.11 mm. Deformation was marginally related to bone type. Sleeve implanted into type A bone experienced 2.45 mm deformation, sleeve implanted into type B bone experienced 0.88 mm deformation, and sleeve implanted into type C bone experienced 0.1 mm deformation (Figure 2). And the largest deformation was observed at 51 years youngest male patient. DISCUSSION:. The small number studied in this study is a limitation. And we are not certain how long the deformation of the sleeve lasts. Despite the limitations, this study showed that deformation of sleeve occurred by impacting the sleeve into the metaphysis, and sleeves implanted into harder bone experienced larger mean deformation than sleeves implanted into less dense bone. This phenomenon may not have been a relevant issue in the past, but recent studies have reported the deformation of metal acetabular cup. The deformation can affect the torsional stability of modular implant connection and fretting corrosion, so further investigation will be needed. The modular femoral stem with sleeve remains an excellent design, providing good initial stability and long-term results. However, greater understanding of sleeve is important to orthopaedic surgeons

Aims. The objective of this study was to compare the two-year migration and clinical outcomes of a new cementless hydroxyapatite (HA)-coated titanium acetabular shell with its previous version, which shared the same geometrical design but a different manufacturing process for applying the titanium surface. Methods. Overall, 87 patients undergoing total hip arthroplasty (THA) were randomized to either a Trident II HA or Trident HA shell, each cementless with clusterholes and HA-coating. All components were used in combination with a cemented Exeter V40 femoral stem. Implant migration was measured using radiostereometric analysis (RSA), with radiographs taken within two days of surgery (baseline), and at three, 12, and 24 months postoperatively. Proximal acetabular component migration was the primary outcome measure. Clinical scores and patient-reported outcome measures (PROMs) were collected at each follow-up. Results. Mean proximal migrations at three, 12, and 24 months were 0.08 mm (95% confidence interval (CI) 0.03 to 0.14), 0.11 mm (95% CI 0.06 to 0.16), and 0.14 mm (95% CI 0.09 to 0.20), respectively, in the Trident II HA group, versus 0.11 mm (95% CI 0.06 to 0.16), 0.12 mm (95% CI 0.07 to 0.17), and 0.14 mm (95% CI 0.09 to 0.19) in the Trident HA group (p = 0.875). No significant differences in translations or rotations between the two designs were found in any other direction. Clinical scores and PROMs were comparable between groups, except for an initially greater postoperative improvement in Hip disability and Osteoarthritis Outcome Symptoms score in the Trident HA group (p = 0.033). Conclusion. The Trident II clusterhole HA shell has comparable migration with its predecessor, the Trident hemispherical HA cluster shell, suggesting a similar risk of long-term aseptic loosening. Cite this article: Bone Joint J 2024;106-B(2):136–143

The Exeter. ™. V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems. A systematic literature search was performed adhering to PRISMA criteria. In parallel we performed a retrospective single centre study of Exeter. ™. V40 femoral stem prosthetic fractures between April 2003– June 2020. There are 25 reported cases of such prosthetic fractures confined to small case series and case reports within the literature. We report an additional 19 cases to the literature (mean age 66.3 ± 11.7 years; 12 female [63%]; body mass index 32.9 ± 5.9 kg/m. 2. ). The mean time from index procedure to fracture was 7.8 years (2.5–16.3, ±3.6). Exeter V40 stem fracture incidence was 0.27%. Incidence was significantly higher in 125 mm length stems compared to ≥150 mm length stems (1.26% vs 0.13%, respectively, p <0.001) and revision arthroplasty (1.209% vs 0.149%, p <0.001). When comparing different stem length cohorts, 125-mm short-stem were associated with stem body fractures (92% vs 29%, p = 0.0095), earlier time to fracture (6.2 vs 11.0 years, p = 0.0018), younger patient age at time of fracture (62.7 vs 72.6 years old, p = 0.037) and female sex (75% vs 43%, p = 0.33). This case series in conjunction with the systematic review provides evidence stem morphology plays a role in femoral implant fracture. This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. As femoral geometries remain the same, increasing BMIs in THR patients should raise concern. Short 125 mm length Exeter V40 stems undoubtedly have a role in restoring anatomy and biomechanics in smaller femoral geometries, although the surgeon has to appreciate the higher risk of stem fracture and the associated predisposing factors which may necessitate meticulous surgical technique and planning

Roentgen Stereophotogrammetric Analysis (RSA) can predict long-term outcome of prostheses by measuring migration over time. The Exeter femoral stem is a double-tapered highly polished implant and has been shown to subside within the cement mantle in 2 year RSA studies. It has a proven track record in terms of long-term survivorship and low revision rates. Several studies have demonstrated excellent clinical outcomes following its implantation but this is the first study to assess stem migration at 10 years, using RSA. This is a single-centre study involving 20 patients (mean age: 63 years, SD=7) undergoing primary total hip replacement for degenerative osteoarthritis using the lateral (Hardinge) approach. RSA radiographs were taken with the patient bearing full weight post-operatively, at 3, 6, 12 months and at 2, 5 and 10 years follow-up. The three-dimensional migration of the Exeter femoral stem was determined. The mean Oxford Hip Score at 10 years was 43.4 (SD=4.6) and there were no revisions. The stems subsided and rotated internally during a 10-year period. The mean migrations of the head and tip of the femoral stem in all three anatomic directions (antero-posterior, medio-lateral & supero-distal) were 0.69 mm posterior, 0.04 mm lateral and 1.67 mm distal for the head and 0.20 mm anterior, 0.02 mm lateral and 1.23 mm distal for the tip. The total migration at 10 years was 1.81 mm for the head and 1.25 mm for the tip. The Exeter femoral stem exhibits migration which is a complex combination of translation and rotation in three dimensions. Comparing our 10 year with our previous 2 year migration results, the Exeter stems show continued, but slow distal migration and internal rotation. The subsidence continues to compress the cement and bone-cement interface which maintains secure fixation in the long term

Introduction. The longevity of total hip replacements in young active patients is a cause for concern as increased cyclical loading can result in early loosening of implants resulting in multiple revisions during the patient's lifetime. The study presented demonstrates excellent survival of the HAC-coated femoral stems in young active individuals. Patients/Materials & Methods. 33 Patients under 50 years of age underwent 38 total hip arthroplasties using the JRI Furlong HAC-coated femoral stem. The retrospective evaluation of the prospectively collected data of the cohort at 17 to 25 years is presented. Results. Of the surviving 34 arthroplasties, 1 hip underwent revision of the stem for peri-prosthetic fracture after 21 years and 1 patient was lost to follow-up. Using aseptic loosening as the end-point, 12 hips (31.5%) needed acetabular revisions but none needed revision of the femoral stem demonstrating 100% survival at a mean of 21 years (95% confidence interval 89% to 100%). Discussion. The excellent survival of the femoral stems can be attributed to various factors. The HAC-coating is present throughout the length of the Furlong stem resulting in bonding along the entirety of the implant. This, further supplemented by the modulus of elasticity of titanium helps the whole proximal femur to function as one unit minimizing the impact of varus or valgus mal-positioning. Furthermore, following osteo-integration, a sealing effect is created in the proximal femur preventing distal migration of the wear particles, which are known to cause osteolysis. The 12 patients that needed revisions for aseptic loosening in our study were confined to the acetabular side. This is a lesser invasive procedure compared to extraction and reconstruction of femoral stems. Conclusion. In young patients with high demands, the Furlong HAC–coated femoral stem gives excellent long-term results

Aims. Hip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane. Methods. Postoperative CT scans of 40 patients who underwent unilateral uncemented total hip arthroplasty were analyzed. Anteroposterior offset (APO) and femoral anteversion were measured on both the operated and non-operated sides. Sagittal tilt of the femoral stem was also measured. APO measured on axial slices was defined as the perpendicular distance between a line drawn from the anterior most point of the proximal femur (anterior reference line) to the centre of the femoral head. The anterior reference line was made parallel to the posterior condylar axis of the knee to correct for rotation. Results. Overall, 26/40 hips had a centre of rotation displaced posteriorly compared to the contralateral hip, increasing to 33/40 once corrected for sagittal tilt, with a mean posterior displacement of 7 mm. Linear regression analysis indicated that stem anteversion needed to be increased by 10.8° to recreate the head centre in the AP plane. Merely matching the native version would result in a 12 mm posterior displacement. Conclusion. This study demonstrates the significant incidence of posterior displacement of the head centre in uncemented hip arthroplasty. Effects of such displacement include a reduction in impingement free range of motion, potential alterations in muscle force vectors and lever arms, and impaired proprioception due to muscle fibre reorientation. Cite this article: Bone Joint Res 2022;11(3):180–188

Version of the femoral stem is an important factor influencing the risk of dislocation after total hip replacement (THR) as well as the position of the acetabular component. However, there is no radiological method of measuring stem anteversion described in the literature. We propose a radiological method to measure stem version and have assessed its reliability and validity. In 36 patients who underwent THR, a hip radiograph and CT scan were taken to measure stem anteversion. The radiograph was a modified Budin view. This is taken as a posteroanterior radiograph in the sitting position with 90° hip flexion and 90° knee flexion and 30° hip abduction. The angle between the stem-neck axis and the posterior intercondylar line was measured by three independent examiners. The intra- and interobserver reliabilities of each measurement were examined. The radiological measurements were compared with the CT measurements to evaluate their validity. The mean radiological measurement was 13.36° (. sd. 6.46) and the mean CT measurement was 12.35° (. sd. 6.39) (p = 0.096). The intra- and interobserver reliabilities were excellent for both measurements. The radiological measurements correlated well with the CT measurements (p = 0.001, r = 0.877). The modified Budin method appears reliable and valid for the measurement of femoral stem anteversion. Cite this article: Bone Joint J 2013;95-B:877–80

Purpose: While the durability of most uncemented femoral stems remains unknown, it is the aim of this study to demonstrate Echelon Primary femoral stem performance with regard patient outcome and overall implant survival. Method: Between February 1998 and March 2007, 428 patients received the Echelon Primary stem. The mean age of each patient was 58.1 (SD 11.1, Range 20–87). Body mass index averaged 30.5 kg/m2 (SD 5.8, Range 17.7–58.2). The majority of patients received a Reflection uncemented acetabular component (91%) and an ultra high molecular weight polyethylene liner (76.5%), although the highly cross linked polyethylene is now used with increased frequency, used in 31% of hips since 2005. The majority of femoral heads were cobalt chrome (79.3%). Results: Kaplan Meier survivorship for the Echelon Femoral stem with revision for aseptic loosening as end point at 100 months is 99.3% (95% CI 97.1–99.8). Taking revision for any reason as the end point the Kaplan Meier survivorship is 98.3% at 100 months (95% CI 95.9–99.3). A pre-operative WOMAC score was available for 345 of the 392 patients with mean score of 43.5 (95% CI 41.6–45.4). At the three-month post-operative review the mean WOMAC score was significantly increased to 74.54 (95% CI 72.7–76.3)(p< 0.001) and by 1 year 84.3 (95% CI 80.5–88.1). At subsequent years, the modified WOMAC score remained at a plateau of around 80. General health assessment using the SF-36 shows an improvement in the physical component score from 33.1 (95% CI 32.3–33.9) preoperatively to 42.6 (95% CI 41.7–43.6)(p< 0.001) at three months and 48.19 (95% CI 44.2–52.2) at latest follow up. The mental component scores increased from 48.7 (95% CI 47.6–49.9) to 51.4 (95% CI 50.3–52.4)(p< 0.001) and 53.5 (95% CI 50.3–56.6) respectively. Conclusion: This large prospective review of the Echelon Primary femoral stems reveals an excellent survivorship of the stem with a 99.3% survival at 8 years with regard aseptic loosening and 98.3% survival including revision for any reason. Patient outcome scores are significantly improved and subsequently maintained. There have been no changes with regard to manufacture or design of the stem within the period of review

Introduction. Varus positioning of cemented ‘composite beam’ stems is associated with increased risks of aseptic loosening and stem fracture. We investigated whether the incidence of varus malalignment of the Exeter polished, double taper design in a multicentre prospective study adversely affected outcome after total hip replacement (THR). Materials & Methods. A multicentre prospective study of 1189 THR was undertaken to investigate whether there is an association between surgical outcome and femoral stem malalignment. The primary outcome measure was the change in the Oxford hip score (OHS) at five years. Secondary outcomes included the rate of dislocation and revision, stem subsidence, quality of cementing. 938 (79.89%) were followed-up at five years. Results. 44 from a total of 1189 femoral stems (3.7%) were implanted in varus (=5° to the femoral axis). Pre-operative demographics and OHS were similar in both groups (p>0.05). Varus implantation was commoner after posterior than anterolateral approach (p< 0.001). Differences in the presence of femoral radiolucency, stem subsidence and quality of cement mantle were not significantly different (p>0.05). There was no difference in absolute OHS or OHS gain between the groups (neutral, mean = 40; varus, mean 40, p = 0.45, OHS gain neutral: 24, varus: 23, p=0.46). Differences in dislocation (p=0.54) or revision rates (p=0.35) were not significant. Conclusion. This study provides evidence that the Exeter stem may be tolerant of varus malalignment, both in terms of patient reported outcome and complication rate up to five years following surgery. Establishing whether aseptic loosening will be more common in the varus group will require longer follow-up

INTRODUCTION. Historically, the clinical performance of novel implants was usually reported by designer surgeons who were the first to acquire clinical data. Regional and national registries now provide rapid access to survival data on new implants and drive ODEP ratings. To assess implant performance, clinical and radiological data is required in addition to implant survival. Prospective, multi-surgeon, multi-centre assessments have been advocated as the most meaningful. We report the preliminary results of such a study for the MiniHip™femoral component and Trinity™ acetabular component (Corin Ltd, UK). METHODS. As part of a non-designer, multi-surgeon, multi-centre prospective surveillance study to assess the MiniHip™stem and Trinity™ cup, 535 operations on 490 patients were undertaken. At surgery, the average age and BMI of the study group was 58.2 years (range 21 to 76 years) and 27.9 (range 16.3 to 43.4) respectively. Clinical (Harris Hip Score, HHS) and radiological review have been obtained at 6 months, 3 and 5 years. Postal Oxford Hip Score (OHS) and EuroQol- 5D (EQ5D) score have been obtained at 6 months and annually thereafter. To date, 23 study subjects have withdrawn or lost contact, 11 have died, and 9 have undergone revision surgery. By the end of March 2018, 6 month, 1, 2, 3, 4, and 5 year data had been obtained for 511, 445, 427, 376, 296 and 198 subjects respectively. RESULTS. Implant revision rate is 1.68% (9/535), with revision for any reason as an endpoint; four of the nine involved the revision of the femoral component. At the 5-year time point, mean OHS had improved from 21.3 to 42.5 (p<0.01), EQ5D from 0.42 to 0.82 (p<0.01), and HHS from 51.6 to 92.5 (p<0.01). Radiological analysis is ongoing, and thus far has revealed more variation in stem alignment than is usually observed for more conventional length femoral components. This may indicate that optimal alignment of calcar loading short stems is different to that of longer, medullary canal aligned implants, consistent with the neck-stabilised design of the MiniHip™ stem. No other significant radiological findings were noted. During surgery, 31 calcar fractures were sustained, of which 20 were treated with cerclage wiring, 1 with femoral grafting and the remainder required no treatment. None of the hips with calcar fractures have been revised to date. DISCUSSION. The clinical and radiological performance of the MiniHip™ femoral stem is consistent with established femoral implants. Longer surveillance will determine whether this performance is maintained. Patients in this study will be continued to be followed-up and reviewed at the 7 and 10-year time points. CONCLUSION. The MiniHip™ stem is safe and efficacious at mid-term follow-up

Introduction: Modular metaphyseal-diaphyseal femoral stems are infrequent in primary total hip arthroplasty. We analyse the results of a proximally hydroxyapatite coated anatomic two-piece modular femoral stem over a minimum five years follow-up. Material and Methods. 94 ESOP (Fournitures Hospitalieres, France) stems are analysed. The mean follow–up was 70.45 + 8.6 months. Patients’ mean age was 65.8 + 9.6 years. Proximal osteopenia and radiographic stem fixation are assessed according to Engh et al. Results: There were 2 aseptic femoral stem loosenings. There were no cases with thigh pain. Three stems presented subsidence. Mean femoral canal filling was 89% and was related to stem subsidence (p< 0.05). Stable bone fixation was obtained in 83 hips and was related to fluted femora (p< 0.0001). The cumulative probability of not having radiographic loosening was 97.8% (94.8% to 100%). The cumulative probability of not having proximal femoral osteolysis was 86.0% (78.9% to 93.1%), cortical widening 88.1% (81.5% to 94.7%), and proximal osteopenia 94.5% (89.8% to 99.2%). Conclusions: A cementless two-piece modular hydroxyapatite coated femoral stem provides good clinical results with an absence of pain and excellent radiographic results when there is good adaptation between the metaphyseal part of the stem and the femoral anatomy. This design is an option in femora with good bone quality and especially in tunnel-shaped cases. Femoral osteopenia and cortical widening were infrequent in this series. The modular metaphyseal-diaphyseal junction is not an in vivo problem, contrary to previous reports. A longer follow-up is needed to assess the results of this design

We describe the association between post-operative femoral stem radiological appearances and aseptic failure of THA (total hip arthroplasty) following a retrospective review of records and radiographs of all patients attending for follow-up between August 2002 and August 2003 who had a cemented Charnley femoral stem and either a cemented polyethylene acetabular cup inserted. Femoral stem aseptic loosening was defined either by findings at revision surgery, the definite radiographic loosening criteria of Harris or progressive endosteal cavitation across zones as described by Gruen. Well-fixed control THAs were defined as those that demonstrated none of the radiographic features of aseptic loosening or ‘at risk’ signs as described by Wroblewski. Parameters measured were: Alignment, Barrack grade of cementation, cement mantle width of the cement mantle and the presence and width of any radiolucent lines. Sixty-three hips were entered into the aseptic failure group and 138 into the control group. The alignment of the femoral stem was not associated with failure (p=0.283). Thickness of the cement mantle was statistically associated with failure in Gruen zones 6 (p=0.040) and Gruen zone 7 (p=0.003). A significant association for the presence of radiolucent lines was found for Gruen zones 3 (p=0.0001) and 5 (p=0.0001). The grade of cementation as measured by the Barrack grade was strongly associated with failure for grades C (p=0.001) and D (p=0.001). This study has demonstrated that easily applied radiological criteria can be used to identify ‘at risk’ Charnley THAs from the immediate post-operative AP radiograph

The fully hydroxyappatite (HA) coated tapered collarless femoral stem has been available worldwide for more than 20 years. However, in Thailand this design became available in 2007. In uncemented collarless tapered and HA coated designs, axial subsidence is a sign of early failure of the implant. This leads to stem instability, loosening and dislocation. To achieve vertical stability, the surgeon should use the correct surgical technique, accurate instrumentation, appropriate stem size and fill in the femoral canal before biologic fixation occurs. This study addresses the axial subsidence of the design. Methods. 46 consecutive total hip arthroplasties with fully HA coated tapered collarless femoral stem (Corail, DePuy) were performed between July 2007-November 2009 by a single surgeon. Patients with at least 6 months follow-up were included in this study. This involved 39 stems. The average follow-up was 11.86 months (6–24 months). The average age at the time of surgery was 58.6 years (37–83 years). Results. 25 stems (64%) had no evidence of subsidence. 14 stems (36%) had some subsidence. The average axial subsidence was 0.68 mm. The femoral canal shape was identified by canal flare index and classified to stovepipe in 12 cases, normal in 20 cases and Champagne –flute in 7 cases. The average axial subsidences at the end of the follow-up period were 0.67 mm, 0.8 mm and 0.25 mm respectively. All cases had no signs of loosening. All subsidences occurred on the first 3 months and no further subsidence was detected at 6 months or more. 12 cases (30%) were aged 60 years or older at time of surgery. In this group, 6 cases (50%) had stovepipe femoral stems (canal flare index <3.0). Conclusion. The fully hydroxyappatite coated tapered femoral stem design shows minimal axial subsidence within the first 3 months after full stability after 6 months

We identified five (2.3%) fractures of the stem in a series of 219 revision procedures using a cementless, cylindrical, extensively porous-coated, distally-fixed femoral stem. Factors relating to the patients, the implant and the operations were compared with those with intact stems. Finite-element analysis was performed on two of the fractured implants. Factors associated with fracture of the stem were poor proximal bone support (type III–type IV; p = 0.001), a body mass index > 30; (p = 0.014), a smaller diameter of stem (< 13.5 mm; p = 0.007) and the use of an extended trochanteric osteotomy (ETO 4/5: p = 0.028). Finite-element analysis showed that the highest stresses on the stem occurred adjacent to the site of the fracture. The use of a strut graft wired over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stresses on the stem by 48%. We recommend the use of a strut allograft in conjunction with an extended trochanteric osteotomy in patients with poor proximal femoral bone stock

Several implants have a proven track record of durability and function in patients over many years. As manufacturers' patents expire it is understandable that cheaper generic copies would be considered. There is currently no established, independent method of determining design equivalence between generic and branded orthopaedic implants. We acquired 10 boxed, as manufactured components consisting of the generic OptiStem XTR model (n=5) and branded Exeter (n=5) femoral stems. Two examiners were blinded to the implant design and independently measured the mass, volume, trunnion surface topography, roughness, trunnion cone angle, CCD angle and femoral offset using peer-reviewed methods. We then compared the stems using these parameters. We found that the OptiStems (1) were lighter (p<0.001) (2) had a rougher trunnion surface (p<0.001) with a greater spacing and depth of the machined threads (p<0.001), (3) had greater trunnion cone angles (p=0.007) and (4) a smaller radius at the top of the trunnion (p=0.007). There was no difference for stem volume (p=0.643), CCD angle (p=0.788) or offset (p=0.993). This study is the first independent investigation of the equivalence of a generic orthopaedic implant to its branded design. We found a clear difference in trunnion roughness, trunnion cone angle and radius, and implant mass when comparing the two generic and branded stem designs. All implants require standard regulatory processes to be followed. It does not appear feasible that generic implants can be manufactured to predictability guarantee the same performance as generic drugs. We found a number of physical differences between the generic and branded implants. Whilst both designs are likely to work in clinical practice, they are different

We report on 397 consecutive revision total hip replacements in 371 patients with a mean clinical and radiological follow-up of 12.9 years (10 to 17.7). The mean age at surgery was 69 years (37 to 93). A total of 28 patients (8%) underwent further revision, including 16 (4%) femoral components. In all 223 patients (56%, 233 hips) died without further revision and 20 patients (5%, 20 hips) were lost to follow-up. Of the remaining patients, 209 (221 hips) were available for clinical assessment and 194 (205 hips) for radiological review at mean follow-up of 12.9 years (10 to 17.7). The mean Harris Hip Score improved from 58.7 (11 to 92) points to 80.7 (21 to 100) (p <  0.001) and the mean Merle d’Aubigné and Postel hip scores at final follow-up were 4.9 (2 to 6), 4.5 (2 to 6) and 4.3 (2 to 6), respectively for pain, mobility and function. Radiographs showed no lucencies around 186 (90.7%) femoral stems with stable bony ingrowth seen in 199 stems (97%). The survival of the S-ROM femoral stem at 15 years with revision for any reason as the endpoint was 90.5% (95% confidence interval (CI) 85.7 to 93.8) and with revision for aseptic loosening as the endpoint 99.3% (95% CI 97.2 to 99.8). We have shown excellent long-term survivorship and good clinical outcome of a cementless hydroxyapatite proximally-coated modular femoral stem in revision hip surgery. Cite this article: Bone Joint J 2014;96-B:730–6

Introduction: We describe the association between postoperative femoral stem radiological appearances and aseptic failure of THA (total hip arthroplasty). Methods: A retrospective review of records and radiographs of all patients attending for follow-up between August 2002 and August 2003 who had a cemented Charnley femoral stem and either a cemented polyethylene acetabular cup inserted. Femoral stem aseptic loosening was defined either by findings at revision surgery, the definite radiographic loosening criteria of Harris or progressive endosteal cavitation across zones as described by Gruen. Well-fixed control THA’s were defined as those that demonstrated none of the radiographic features of aseptic loosening or ‘at risk’ signs as described by Wroblewski. Parameters measured were: Alignment, Barrack grade of cementation, cement mantle width of the cement mantle and the presence and width of any radiolucent lines. Results: 63 hips were entered into the aseptic failure group and 138 into the control group. The alignment of the femoral stem was not associated with failure (p=0.283). Thickness of the cement mantle was statistically associated with failure in Gruen zones 6 (p=0.040) and Gruen zone 7 (p=0.003). A significant association for the presence of radiolucent lines was found for Gruen zones 3 (p=0.0001) and 5 (p=0.0001). The grade of cementation as measured by the Barrack grade was strongly associated with failure for grades C (p=0.001) and D (p=0.001). Discussion and conclusion: This study has demonstrated that easily applied radiological criteria can be used to identify ‘at risk’ Charnley THA’s from the immediate post-operative AP radiograph

Introduction. The orthopaedic market offers more than two hundred different hip femoral stems. Of these, very few have undergone scientific studies with published results. The differences of designs of the stem are mainly related to surface texture and geometry sections. The development of a new cemented hip prosthesis is certainly a very hard task if aiming the improvement of actual performance. Materials and Methods. This study presents the influence of geometric variables in a novel hip stem concept which was based on the comparison of the performance of the best cemented stems actually in the market. The study was developed using finite element analysis and experiments with in vitro femoral replacements. A numerical simplified model of the hip replacement was designed to generate the final geometry of the femoral stem section. After an in vitro cemented commercial stem was done, with the best cemented stem a Lubinus, Charnley, Stanmore and Müller. Realistic numerical models also allowed us to determine cement mantle stresses of commercial femoral stems that were compared with those obtained for the new concept stem. The new model was then prototyped and tested through in vitro fatigue tests. Finally fatigue tests were also performed to determine the density of cracks in the cement mantles, as well as debonding for both conventional and new designs. Results. Stem section geometry influences the fatigue mechanism at the stem–cement interface and is an important factor in the load transfer. The organic section presents 60% (average) less cement stress than sharp sections. Concerning the new stem, detail design geometry parameters were analyzed, such as collar position and orientation, medial radius and geometry of the stem tip. The simulations performed show that the new stem design presents 98.5% of cement volume under an equivalent stress lower than 3 MPa [FIG 1]. The correlation factor between this percentage with the clinical follow up results for 10 years of commercial stems is 0.964, being p=0.641 the significance level of one tailed Person correlation. Discussion. The variables associated to the stem geometry presents influence in the cement mantle stress and could improve the success. The section of stem is an important factor to improve the load transfer. The [FIG. 2] presents a resume of some variables in a new concept. The inclination of collar 5° at sagital plane reduces the stress in 10% proximally. The tip geometry influences the stress in cement and improves the femoral position. The tip geometry could reduce 20% of cement stress in distal region. Conclusions. The new femoral design was based on the findings of the finite element analysis and fatigue tests. It presents an innovative collar, “organic” geometry sections and a geometry tip that minimizes stress concentration. The stem developed reduces the cement stresses in an average of 25% relatively to the commercial stems used in the study. The work demonstrates in a new hip concept that small details in design of cemented hip may have consequences in the implant success

Introduction: Fractures of the femoral stem component in total hip Arthroplasty have been a well documented complication. The incidence over recent years has decreased due to improvements in surgical technique and implant design and manufacture. Methods/Results: We report two cases of femoral stem fracture. Both occurred in CDH stems from the C-stem system (Depuy International, Leeds, UK). These are the first reported fractures in this stem. Both patients were women weighing 83kgs and 98kgs at the time of fracture giving them BMI’s of 31 and 41 respectively. In both cases the BMI had increased since the time of operation. Discussion: The design of the CDH stem is fundamentally different from the rest of the standard stems with absence of the medial strut. In addition to this factor, both stems fractured through the insertion hole which acted as a stress raiser. Finally both patients BMI’s were above 25. At the time of operation no weight limit was imposed on this prosthesis. We conclude that if possible, a standard C-stem should be inserted but if a CDH stem is used attention to patients’ weight is paramount

Purpose. In an effort to increase the durability of cemented total hip arthroplasties (THA), femoral stems were precoated using polymethlymethacrylate (PMMA). One such design is Harris precoat plus and centralign design (Zimmer, Warsaw, Indiana). The reports on these particular designs are variable, ranging from good survival to early failures, studied over short to medium term. Early failures have been attributed, most of the time to debonding at cement-bone interface. In view of lack of long term and variable results, we reviewed the results of primary hybrid THA performed during October 1990 to December 1995, using a PMMA coated, cemented femoral prosthesis and contemporary cementing techniques. Materials and Methods. 121 patients (136 hips) underwent primary THA using one of the precoated femoral stems during the study period. Thirty-five patients (36 hips) died and 23 patients (23 hips) were lost to follow-up due to some reasons. Two hips (2 patients) were revised for postoperative infection and hence, not included in study. Collectively, 75 hips (61 patients) were available for clinical and radiological reviews until the last follow-up, with an average follow-up period of 15.5 years (range, 14 to 18.3 years). The average age of the patients at the time of the index surgery was 53.6 years (range, 24 to 82 years). There were 43 males (55 hips) and 18 females (20 hips). Acetabular components used in these 75 hips were Harris Galante porous (HGP) cups in 69 hips and CLS Expansion cup (Protek, AG, Bern) in six hips. The mean age of 61 patients (75 hips) who were available for latest follow-up at December 2009, was 46 years (range, 22-65 years). Third generation cementing techniques and distal cement plug but no centralizer was used in all cases. All surgeries were performed by same surgeon at a single institute. Results. 23 femoral stems were revised, 20 for aseptic loosening (8 Precoat plus and 12 Centralign) and 3 for periprosthetic fracture with loosening (1 Precoat plus and 2 Centralign). The cementing of the femoral stem was grade A in 29 hips (39%), grade B in 16 (21%), C1 in 6 (8%) and grade C2 in 24 (32%). 21 of 24 hips which showed definitive loosening in radiogram had had cement grade C2 cementing. There were 22 acetabular revisions. 11 hips underwent isolated liner exchange for severe wear and osteolysis and in remaining 11 hips, complete acetabular component revision was performed. Indications for acetabular component revisions were aseptic loosening in five, severe lysis in four, extensive wear and metallosis in one, and liner dissociation in one. In one hip, with a fractured acetabular component due to severe pelvic bone defect, both the components were revised. Conclusion. Our results suggest that an early failure of the precoated femoral stem was mainly precipitated due to insufficient cementing technique (a thin cement mantle). Inherent flaws of the stem design may also accelerate the mechanism of failure

Introduction. Varus malpositioning of femoral stems has been recognised as a poor prognostic feature with regard to loosening and failure of cemented composite beam implants, but there have been no published results of the long-term effect on taper-slip designs. Objectives. To determine the results of varus placement of a polished triple tapered femoral stem. Methods. We have prospectively analysed the results of 350 consecutive polished triple-tapered C-Stem implants performed on 322 patients between March 2000 and July 2004, using a standard posterior approach and Palacos-R cement. All patients underwent annual clinical and radiological review. Results. The average duration of follow-up in surviving patients is 140 months (120–172 months). There were 49 femoral implants in 49 patients implanted with more than 5 degrees of varus (14%) with respect to the long axis of the femur, and 14 in 14 patients in more than 5 degrees of valgus (4%). Alignment within 5 degrees of neutral was achieved in 82% of cases. The average age in the varus group was 69.2 years (41–92), which was higher than in the neutral group (67.4 years: 25–89), more patients were male (49% v 36%) but the average BMI was similar (29 v 28). The average duration of follow-up was the same. There was only one re-operation in the varus group, which was a revision for deep infection. There was one dislocation successfully treated by closed reduction and one acetabular component is currently loose. In the neutral group there have been four dislocations, one of which required application of a PLAD; five revisions for aseptic loosening of the acetabular component associated with high wear rates, with a further three currently being loose; four intra-operative, undisplaced fractures of the greater trochanter; two peri-prosthetic femoral shaft fractures treated by internal fixation and two temporary nerve palsies. There has been no aseptic loosening of the femoral components in either group. Subsidence of the femoral stem within the cement mantle was noted in 96% of the entire series. There was no significant difference between the groups with respect to the degree of subsidence. In the varus group 78% subsided less than 2mm compared to 75% in the neutral group. None of the femoral implants in either group subsided more than 4mm and none demonstrated evidence of aseptic loosening or negative bone remodelling. Conclusion. Varus implantation of the femoral component was more common in older, male patients, but there was no increased risk of subsidence or loosening at a minimum follow-up of ten years

Aim: The objective of this study was to compare the initial stability of an uncemented curved long stem femoral component (ABR, Zimmer, Warsaw Indiana) implanted using conventional broaching to an uncemented ABR implanted as a revision using morselized compacted allograft to fill a circumferential proximal bone defect. Materials and Methods: Primary: Eight fresh frozen human femurs were implanted with correctly sized ABR stems without cement using standard surgical instruments and 1mm distal overreaming. The implant was loaded cyclically at 3 hz on a MTS servohdraulic materials test frame in a direction representing the peak force of the stance phase of the gait (2.5 X body weight). A 3-dimensional motion measurement device with six linear variable transformers measure the relative motion between the bone and the prosthesis with an accuracy of 0.5μm. The contruct was loaded in ten cycle increments until the component was seated and then recoverable motion was recorded over a further ten loading cycles. Revision: In the revision case bone loss was modelled by removing all the cancellous bone from the proximal femur with 1mm distal overreaming. Morselized bone graft was impacted into the defect using specially prepared smooth tamps shaped to the geometry of the ABR stem. The original prosthesis was then reimplanted without the use of cement. The seating and testing cycles were repeated. Primary and revision vectors were compared using a paired students t – test. Results: There was no statistically significant difference in the magnitude of the resultant vector of the 3 translational components of the micro motion between the two methods of implantation (p=0.19). Conclusions: Initial stability of a cementless femoral implant is a requirement for bone ingrowth. The use of compacted morsellized allograft in a revision Total Hip Arthroplasty with a proximal circumferential defect can provide a stable bed for the implantation of an uncemented femoral component. The revised implant using the compacted allograft method was initially as stable as the primary implantation. This technique would be particularly applicable when the surgeon would like to avoid the use of cement in a revision setting. The use of this method for uncemented revision Total Hip Arthroplasty should be studied further in a clinical setting before it is advocated for widespread use