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

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

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

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

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

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

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

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

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

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

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

To assess whether prosthetic femoral stem centralisers have a detrimental effect on the macroporosity of the cement mantle, and if so, whether this is independent of their design and the rate of implantation, 30 identically cast moulded prosthetic femora were divided into 3 groups. Group 1: no centraliser (control), Group 2: centraliser A and Group 3: centraliser B. Using third generation cementation techniques and pressure monitoring, Charnley C-stems +/− the appropriate centraliser were implanted to a constant depth. Half in each group were implanted as rapidly as possible and the other half over 90 seconds. The stems were removed and the cement mantle then underwent a preliminary arthroscopic examination prior to being sectioned transversely at 3 constant levels. Each level was then photographed and digitally enlarged to a known scale to allow examination and determination of any cement voids (macropores) surface area. There were no significant pressure fluctuations between the groups. Preliminary arthroscopic examination revealed that cement voids appeared more common when a centraliser was used. This difference was confirmed (p=0.002) following sectioning of the specimens, with cement voids found in 85% of femora when a centraliser was used and only 20% in the control group. Centraliser B performed worst with cement voids of a larger volume and more frequent occurrence (p=0.002). The macroporosity of the cement mantle was independent of the rate of implantation (p=0.39). The use of femoral stem centralisers is helpful in preventing malposition of the implant but results in increased macroporosity of the cement mantle. This may have implications regarding the longevity of an implant in terms of early loosening and therefore their design and use must always be carefully considered

Background. There is increasing impetus to use rapid recovery care pathways when treating patients undergoing total hip arthroplasty (THA). The direct anterior (DA) approach is a muscle sparing technique that is believed to support these new pathways. Implants designed for these approaches are available in both collared and collarless variations and understanding the impact each has is important for providing the best treatment to patients. Purpose/Aim of Study. This study aims to examine the role of implant design on implant fixation and patient recovery. Materials and Methods. Patients (n=50) with unilateral hip OA who were undergoing primary DA THA surgery were recruited pre-operatively to participate in this prospective randomized controlled trial. All patients were randomized to receive either a collared (n=25) or collarless (n=25) cementless, fully hydroxyapatite coated femoral stem. Patients were seen at nine appointments (pre-operative, <24 hours post-operation, two-, four-, six-weeks, three-, six-months, one-, and two-years). Patients underwent supine radiostereometric analysis (RSA) imaging <24 hours post-operation prior to leaving the hospital, and at all follow-up appointments. Patients also completed an instrumented timed up-and-go (TUG) test using wearable sensors at each visit, excluding the day of their surgery. Participants logged their steps using Fitbit activity trackers and a seven-day average prior to each visit was recorded. Findings/Results. Twenty-two patients that received a collared stem and 27 patients that received a collarless stem have been assessed. There were no demographic differences between groups. From <24 hours to two weeks the collared implants subsided 0.90 ± 1.20 mm and the collarless implants subsided 3.80 ± 3.37 mm (p=0.001). From two weeks to three months the collared implants subsided 0.67 ± 1.61 mm and the collarless implants subsided 0.45 ± 0.46 mm (p=0.377). Step count was reduced at two weeks to 3108 ± 1388 steps for collared patients and 2340 ± 1685 steps for collarless patients (p=0.072). Step count was increased at three months to 8939 ± 3494 steps for collared patients and 6114 ± 2529 steps for collarless patients (p=0.034). TUG test time was increased at two weeks compared to pre-operatively by 3.45 ± 6.01 s for collared patients and 2.29 ± 4.92 s for collarless patients (p=0.754). TUG test time decreased from two weeks to three months by 6.30 ± 6.05 s for collared patients and 5.68 ± 4.68 s for collarless patients (p=0.922). Conclusions. Collared implants subsided less in the first two weeks compared to collarless implants but subsequent subsidence after two weeks was not significantly different. Presence of a collar on the stem impacted patient activity but not function. This suggests that both the implant design as well as the surgical technique may play a role in the patient's early post-operative experience

Introduction. Many patients who had previous proximal femoral osteotomies develop deformities that may not be amenable to total hip replacement (THR) with standard off-the-shelf femoral stems. Previous studies have shown high revision rates (18% at 5–10 years follow-up). Computer-assisted-design computer-assisted-manufacture (CAD-CAM) femoral stems are indicated but the results are not known. We assessed the clinical results of THR using CAD-CAM femoral stems specifically for this group of patients. Methods. We included patients with previous proximal femoral osteotomy and significant deformity who underwent THR with CAD-CAM femoral stem operated by the senior author (AHN) from 1997 with a minimum of 5 years follow-up. We noted revision rates, associated complications and functional outcome. Radiological outcomes include assessment for loosening defined as development of progressive radiolucent lines around implant or implant migration. Results. We included 54 patients (57 THRs) at a mean age of 32 years (range 19 to 49) with a mean follow-up of 9.1 years (range 5.9–12.8). There was 2 (3.5%) stem revision for loosening. Seven polyethylene liners were revised because of eccentric wear/osteolysis after a mean of 10 years (range 7–11.5) but there was no associated radiological stem loosening. Other associated complications include 2 (3.5%) intraoperative femur fractures, 1 (1.8%) infection treated with antibiotics and 1 (1.8%) greater trochanteric fracture non-union. At the last follow-up review, the mean Oxford hip score was 35 (11–48) and the mean UCLA activity score was 5.1 (3–10). Conclusion. In contrast to previous studies that have shown high revision rates for THR in patients with previous proximal femoral osteotomy and osteotomy, the use of CAD-CAM hip stems has shown good mid- to long-term clinical outcomes with a considerably lower revision rate

INTRODUCTION:. Short femoral stems are receiving increasing attention for less invasive total hip replacement (THR). The purpose of this study is to report our initial experience with a short modular femoral (SMF) stem at a minimum two-year follow up. METHODS:. Twenty-six primary total hip arthroplasties (THAs) using the SMF stem were performed between August 2009 and January 2010. Patients were evaluated clinically with Harris Hip Score (HHS) and radiographically up to two years. Radiographs were analyzed to determine the degree of stem migration from its initial postoperative position. These parameters were compared to those of a cohort of 54 patients implanted with a monolithic tapered wedge stem from the same manufacturer over the same time period. RESULTS:. There were three early revisions of the femoral component for thigh pain in the SMF group, and one revision for CoCr allergy, with improvement in HHS from 60 to 89. Radiographically, 20 of 26 stems (76%) migrated into varus in the first six weeks. Of these, eight patients (29.6%) reported moderate to severe thigh pain. Radiographic evidence of isolated lateral cortical hypertrophy at the stem tip was seen in 46% of study patients, and evidence of osteointegration was seen in all cases by one year. Between one and two years post op the pain had resolved in four patients not revised. It was persistent in one patient. Comparative analysis with the control group demonstrated no significant difference in stem subsidence, but a significantly greater varus shift in coronal-plane angulation (Mean 4.3°, SD 3.8° vs. Mean 1.0°, SD 1.1°; p < 0.0001). Mean HHS was lower in the SMF group (85.2 vs. 91.4; p < 0.01) at last follow up. DISCUSSION AND CONCLUSION:. The SMF stem demonstrated a tendency towards migration into a varus position where the lateral stem touches the lateral cortex of the femur, with resulting relatively higher incidence of thigh pain and early aseptic revision