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

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. 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

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

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

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

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

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