Cemented Femoral Stem Research Articles

SIMULTANEOUS VERSUS STAGED TOTAL HIP ARTHROPLASTY FOLLOWING ACETABULAR FRACTURE FIXATION: A COMPARISON OF OUTCOMES

Acetabular fractures present a challenge. Anatomical reduction can be achieved by open reduction and internal fixation (ORIF). However, in elderly patients with complex fracture patterns and osteoporotic bone stock, “fix and replace” has become an option in the management of these injuries. This involves ORIF of the acetabulum to enable insertion of a press fit cup and subsequent cemented femoral stem at the index surgery.A Retrospective analysis of all operatively managed acetabular fractures by a regional Pelvic and Acetabular Trauma service (01/01/2018-30/05/2023) STATA used for analysis. 34 patients undergoing “fix and replace” surgery. Of the 133 patients managed with ORIF, 21 subsequently required Total Hip Arthroplasty (THA). Mean follow up was 2.7 years versus 5.1. There was no statistical significance between the two groups with regards to BMI or sex. Mean age in the “fix and replace” group was 68 compared to 48 in the ORIF and subsequent THA group. This reached statistical significance between the two groups (p=0.001).ASA and Charlson Comorbidity Index (3 and 3 in “fix and replace” and 2 and 1.2 in ORIF to THA group) and Charlson Comorbidity Index both were statistically significantly different (p=0.006 and p=0.027, respectively). High energy mechanism of injury accounted for 56% of the “fix and replace” group compared to 48% in the ORIF to THA. 74% of “fix and replace” were associated fractures compared to 53% of ORIF to THA. Wait to surgery was 3 days for “fix and replace” while 186 days was the mean wait time from listing to THA for the ORIF to THA group. Complication rate was 41% versus 43% in the two groups. 14% in the ORIF to THA group developed PJI versus 6% in “fix and replace”.Fix and replace allows early mobilisation in frailer, elderly patients. Our results show fewer returns to theatre and less PJI in patients having arthroplasty as part of “fix and replace” than subsequent to Open reduction internal fixation.

Design and In Vitro Validation of an Orthopaedic Drill Guide for Femoral Stem Revision in Total Hip Arthroplasty.

Cemented total hip arthroplasty (THA) demonstrates superior survival rates compared to uncemented procedures. Nevertheless, most younger patients opt for uncemented THA, as removing well-fixed bone cement in the femur during revisions is complex, particularly the distal cement plug. This removal procedure often increases the risk of femoral fracture or perforation, haemorrhage and weakening bone due to poor drill control and positioning. Aim of this study was to design a novel drill guide to improve drill positioning. A novel orthopaedic drill guide was developed, featuring a compliant centralizer activated by a drill guide actuator. Bone models were prepared to assess centralizing performance. Three conditions were tested: drilling without guidance, guided drilling with centralizer activation held, and guided drilling with centralizer activation released. Deviations from the bone centre were measured at the entry and exit point of the drill. In the centralizing performance test, the drill guide significantly reduced drill hole deviations in both entry and exit points compared to the control ([Formula: see text]). The absolute deviation on the exit side of the cement plug was 10.59mm (SD 1.56) for the 'No drill guide' condition, 3.02mm (SD 2.09) for 'Drill guide - hold' and 2.12mm (SD 1.71) for 'Drill guide - release'. The compliant drill guide centralizer significantly lowered the risk of cortical bone perforation during intramedullary canal drilling in the bone models due to better control of the cement drill position. Clinical and Translational Impact Statement: The drill guide potentially reduces perioperative risks in cemented femoral stem revision. Future research should identify optimal scenarios for its application.

Reduced mortality associated to cementless total hip arthroplasty in femoral neck fracture

Mortality related to femoral neck fractures remains a challenging health issue, with a high mortality rate at 1 year of follow-up. Three modifiable factors appear to be under control of the surgeon: the choice of the implant, the use of cement and the timing before surgery. The aim of this research project was to study the impact on mortality each of these risk factors play during the management of femoral neck fractures. A large retrospective epidemiological study was performed using a national database of the public healthcare system. The inclusion criteria were patients who underwent joint replacement surgery after femoral neck fracture during the years 2015 to 2017. All data points were available for at least 2 years after the fracture. The primary outcome was mortality within 2 years following the surgery. We evaluated the association between mortality and the type of the implant hemiarthroplasty (HA) versus total hip arthroplasty (THA), cemented versus non cemented femoral stem as well as the timing from fracture to surgical procedure. A multivariate analysis was performed including age, gender, comorbidities/autonomy scores, social category, and obesity. We identified 96,184 patients who matched the inclusion criteria between 2015 and 2017. 64,106 (66%) patients underwent HA and 32,078 (33.4%) underwent THA. After multivariate analysis including age and comorbidities, patients who underwent surgery after 72 h intra-hospital had a higher risk of mortality: Hazard Ratio (HR) = 1.119 (1.056–1.185) p = 0.0001 compared to the group who underwent surgery within 24 h. THA was found to be a protective factor HR = 0.762 (0.731–0.795) p < 0.0001. The use of cement was correlated with higher mortality rate: HR = 1.107 (1.067–1.149) p < 0.0001. Three key points are highlighted by our study in the reduction of mortality related to femoral neck fracture: the use of hemiarthroplasty a surgery performed after 48 h and the use of cement for femoral stem fixation adversely affect mortality risk.

Cost-Effectiveness of Bone Cement With and Without Antibiotics: A Broader Perspective

Background Periprosthetic joint infections (PJIs) and periprosthetic femur fractures (PFFs) increase total costs of care. Retrospective registry/institutional studies with selection bias and underpowered meta-analyses have corrupted the evidence base regarding antibiotic-laden bone cement (ALBC) use in total knee arthroplasties (TKAs). Clinical practice guidelines (CPGs) recommend using cement fixation of femoral components in hip fracture patients to prevent PFFs, but have no recommendations regarding ALBC. Hip osteoarthritis CPGs have no bone cement recommendations regarding prevention of PJIs or PFFs. ALBC is potentially cost-effective by reducing PJIs, PFFs, and reducing implant costs. Methods A systematic review was conducted to identify randomized controlled trials (RCTs), meta-analyses, and registry reports related to the efficacy of ALBC in reducing PJIs and cemented femoral fixation in reducing PFFs. Numbers needed to treat (NNT) are calculated. Cost-effectiveness margins per case are calculated. Results A pooled analysis of four TKA RCTs found ALBC reduces PJI by 0.94% (p=0.027), NNT 106. A total hip arthroplasty (THA) meta-analysis found ALBC reduces PJI by 0.58% (p&lt;0.0001), NNT 172. A hip hemiarthroplasty (HH) RCT found high-dose dual-antibiotic ALBC reduces PJI by 2.35% (p=0.0474), NNT 43. A THA registry report found that cemented fixation compared to ingrowth fixation reduced PFFs by 0.44% (p&lt;0.0001), NNT 229. A pooled analysis of three HH RCTs found that cemented femoral stem fixation reduced PFFs by 5.09% (p-0.0099), NNT 20. Mean PJI treatment costs are $80,000. Mean PFF treatment costs are $27,596. Mean HH cemented femoral stem cost reduction: $685. Using ALBC: TKA margin/case is $755; THA margin/case is $586; and HH margin/case is $3,925. Using plain bone cement: TKA margin/case is $0; THA margin/case is $121; and HH margin/case is $2,065. Conclusions A broader perspective demonstrates that ALBC provides significant financial margins in TKAs, THAs, and hip hemiarthroplasties. ALBC is cost-effective when including the additional costs of using ALBC in TKAs, THAs, and hip hemiarthroplasties. Hand-mixed ALBC is more cost-effective than pre-mixed ALBC in all scenarios.

Influence of Scan Parameters of Single and Dual-Energy CT Protocols in Combination with Metal Artifact Suppression Algorithms for THA: An ex Vivo Study.

Metal artifacts caused by hip arthroplasty stems limit the diagnostic value of computed tomography (CT) in the evaluation of periprosthetic fractures or implant loosening. The aim of this ex vivo study was to evaluate the influence of different scan parameters and metal artifact algorithms on image quality in the presence of hip stems. Nine femoral stems, 6 uncemented and 3 cemented, that had been implanted in subjects during their lifetimes were exarticulated and investigated after death and anatomical body donation. Twelve CT protocols consisting of single-energy (SE) and single-source consecutive dual-energy (DE) scans with and without an iterative metal artifact reduction algorithm (iMAR; Siemens Healthineers) and/or monoenergetic reconstructions were compared. Streak and blooming artifacts as well as subjective image quality were evaluated for each protocol. Metal artifact reduction with iMAR significantly reduced the streak artifacts in all investigated protocols (p = 0.001 to 0.01). The best subjective image quality was observed for the SE protocol with a tin filter and iMAR. The least streak artifacts were observed for monoenergetic reconstructions of 110, 160, and 190 keV with iMAR (standard deviation of the Hounsfield units: 151.1, 143.7, 144.4) as well as the SE protocol with a tin filter and iMAR (163.5). The smallest virtual growth was seen for the SE with a tin filter and without iMAR (4.40 mm) and the monoenergetic reconstruction of 190 keV without iMAR (4.67 mm). This study strongly suggests that metal artifact reduction algorithms (e.g., iMAR) should be used in clinical practice for imaging of the bone-implant interface of prostheses with either an uncemented or cemented femoral stem. Among the iMAR protocols, the SE protocol with 140 kV and a tin filter produced the best subjective image quality. Furthermore, this protocol and DE monoenergetic reconstructions of 160 and 190 keV with iMAR achieved the lowest levels of streak and blooming artifacts. Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Тотальное эндопротезирование тазобедренного сустава в течение последних 25 лет

Тотальное эндопротезирование тазобедренного сустава (ТЭТС) является одной из наиболее клинически эффективных и экономически целесообразных ортопедических процедур в течение последних пяти десятилетий. Прочность фиксации цементной бедренной ножки остается стандартом, с которым сравнивают все современные методы фиксации. Выживание ножек составило 82 % при 20-летнем периоде и 81 % при 30-летнем. При этом выживание ацетабулярных чашек составило 71 и 52 % соответственно. В североамериканском регистре больных с протезированием тазобедренного и коленного суставов использование цементных чашек уменьшилось с 12 % в 1995 году до 7,8 % в 2001 году. Клинические данные не указывают на стойкие клинические преимущества методов малоинвазивной хирургии (Minimally Invasive Surgery, MIS) по сравнению с традиционными хирургическими доступами. Нередко встречаются серьезные осложнения, связанные с использованием данного метода. В последнее десятилетие наблюдается резкое снижение частоты клинического использования методов MIS при ТЭТС. В период с 1993 года во всем мире наблюдалось последовательное увеличение объемов поверхностного эндопротезирования тазобедренного сустава. До 2008 года поверхностное эндопротезирование тазобедренного сустава составляло 6–9 % от всех ТЭТС. Несмотря на заинтересованность больных поверхностным эндопротезированием, боязнь осложнений и выживание имплантатов в длительной перспективе, а также неизвестные последствия влияния ионов металлов и связанные с ними неблагоприятные тканевые реакции привели к сокращению количества поверхностного эндопротезирования тазобедренного сустава в большинстве стран. Инновации в области обработки полиэтилена привели к улучшению его износостойких характеристик. Идеальный полиэтиленовый материал должен иметь высокую плотность поперечных связей (крепкая межмолекулярная связь) и низкий потенциал окисления. Это достигается за счет увеличения дозы облучения, которая подается на полиэтилен (до 10 Мрад), что увеличивает количество поперечных связей. Чтобы снизить окислительный потенциал, компоненты облучают в бескислородной среде с барьерной упаковкой. Существует ограниченное количество доказательств сравнительной эффективности разных пар трения тазобедренных суставов. Рандомизированные клинические исследования демонстрируют похожие коротко- и среднесрочные периоды выживания среди керамо-керамической пары трения, керамики с кросс-линкованным полиэтиленом и металла с кросс-линкованным полиэтиленом у больных моложе 65 лет. Керамические головки приобретают все большую популярность по сравнению с металлическими головками. Огромные различия до сих пор существуют среди стран по частоте использования цементной и бесцементной фиксации. В 2013 году в некоторых странах использование цементных ножек было меньше 4 %, в других странах оно составляло более 68 % в том же году. Во всем мире сегодня существует тенденция к увеличению количества бесцементной фиксации. Общенациональная база данных пациентов США демонстрирует причины проведения ревизионного ТЭТС: среди 51 345 повторных ТЭТС вывихи составляли 22,5 %, асептическая нестабильность — 19,7 %, инфекция — 14,8 %. В 2030 году клиническая потребность в первичном ТЭТС увеличится на 174 %, до 572 000 случаев в год, по сравнению с 2002 годом, а спрос на ревизионное ТЭТС увеличится на 137 % до 2030 года.

Influence of implant variations on survival of the Lubinus SP II stem: evaluation of 76,530 hips in the Swedish Arthroplasty Register, 2000–2018

Background and purpose — Almost all prosthetic implant brands include several variations. Most studies on implant performance investigate an implant system without sub-analysis of implant attributes. We studied the influence of design variations during the last 2 decades on implant survival of the most frequently used cemented femoral stem, the Lubinus SPII, reported to the Swedish Arthroplasty Register (SHAR). Patients and methods — Between 2000 and 2018, 100,032 cemented Lubinus SP II stems had been reported to SHAR. Patients with primary osteoarthritis operated on with stem length 150 mm together with a cemented cup from the same manufacturer (n = 76,530) were included in this analysis. Primary study outcome was non-infectious stem revision. Cox regression with adjustment for age, sex, surgical approach, and year of surgery was used. Hazard rates (HR) are presented with 95% confidence intervals (CI). Results — Average follow-up was 7.6 years (SD 4.2). At 18 years the overall stem survival was 99.1 (CI 98.9–99.3). Increased revision rate was observed for stems with extra offset, when a long or an extra-long head length had been used. Smaller stem sizes, in particular the smallest stem size (01), substantially increased the rate of mechanical failure as reflected by an almost 10 times increased rate of revision compared with the standard size (2). Interpretation — In this study with larger sample size and longer follow-up than previously presented from the same register, we observed more pronounced effects of previously documented design variations. Based on our results, surgeons using the Lubinus SPII stems are advised to consider an alternative solution if a Lubinus stem size 01, Lubinus extra offset, or an extra-long head seems to be the most suitable choice at the preoperative planning.

An Alternative One-Stage Exchange Arthroplasty Technique: For the Chronic Infected Total Hip.

BackgroundThere are various algorithms for the treatment of prosthetic joint infections (PJI). Currently, a two-stage hip exchange is considered the “gold standard” of care for treatment of chronic hip PJIs. However, there has been recent debate whether a one- or two-stage exchange offers the correct treatment. One-stage exchange arthroplasty has particularly gained interest due to less morbidity, mortality, and functional impairment.MethodsIn a retrospective case series, the outcome of patients with chronic hip PJIs treated with our one-stage exchange arthroplasty was analyzed. Between January 2015 and January 2020, eight patients underwent a one-stage exchange hip arthroplasty by a single surgeon at a single institution for a chronically infected total hip arthroplasty (THA). Original diagnosis of PJI was made in accordance with the 2011 version of the Musculoskeletal Infection Society (MSIS) criteria. The femoral stem was cemented with antibiotic-impregnated cement, and the polyethylene acetabular liner was cemented directly onto the acetabular bone with antibiotic-impregnated cement.ResultsOf the eight patients, three were female and five were male with a mean age of 70.5 years (SD 11.2, range 53-87). Six patients (75%) had infection eradication with retention of a stable implant and no additional surgery at a mean follow-up of 35.7 months (range 17-50). One patient (12.5%) underwent closed reduction for a dislocated THA at one month; however, this patient remained infection-free at the most recent follow-up of 41 months. One patient (12.5%) who was the oldest patient (87 years) died 18 days postoperatively. Overall, all living patients (87.5%) retained their one-stage exchange THA. One patient (12.5%, CI 95% 0.3-52.7) required additional surgery in the form of a closed reduction and zero patients (0.0%, CI 95% 0.0-36.9) required additional open surgery. ConclusionSingle-stage exchange arthroplasty with an antibiotic-impregnated cemented femoral stem and antibiotic-impregnated cemented polyethylene acetabular liner may be a useful option for the treatment of chronic hip PJIs. Our case series provides evidence that infection eradication and function preservation are possible using our one-stage exchange arthroplasty technique in a chronically infected THA. However, a multi-center study with randomization is necessary to further validate our results.

The Use of Standard Cemented Femoral Stems in Total Hip Replacement After Failed Internal Fixation of Intertrochanteric Femoral Fractures

BackgroundTotal hip replacement (THR) after failed internal fixation of intertrochanteric femoral fractures is challenging. The aim of this study is to show the reliability of using standard cemented femoral stems in this operation. MethodsThis work included 107 THRs performed in 107 patients after failed treatment of intertrochanteric femoral fractures. The etiology of failure included 67 cases of failure of fixation, 16 cases of nonunion, 15 cases of avascular necrosis, and 9 cases of post-traumatic osteoarthritis. There were 48 males and 59 females. The mean age was 66 years (range 58-81). Failed dynamic hip screws were removed at the time of THR, and the screw holes were blocked with cement. All cases had cemented standard stem femoral prostheses. ResultsAt an average 7.4 years with a minimum of 5 years of follow-up, 102 cases had good clinical and radiological outcomes and 5 cases had fair outcomes. One patient was infected and required 2 stages of revision arthroplasty. Two cases had intraoperative proximal femoral crack, and were treated by cerclage wires. Two patients had early postoperative dislocations. No patients had late periprosthetic femoral fractures or implant loosening. ConclusionStandard cemented femoral stems are reliable and cost-effective prostheses in such cases. It is not necessary to bypass the distal screw hole by doubling the femoral canal diameter as long as the bone holes are covered by cement.

Current concepts and outcomes in cemented femoral stem design and cementation techniques: the argument for a new classification system.

Cemented implant fixation design principles have evolved since the 1950s, and various femoral stem designs are currently in use to provide a stable construct between the implant–cement and cement–bone interfaces.Cemented stems have classically been classified into two broad categories: taper slip or force closed, and composite beams or shaped closed designs. While these simplifications are acceptable general categories, there are other important surgical details that need to be taken into consideration such as different broaching techniques, cementing techniques and mantle thickness.With the evolution of cemented implants, the introduction of newer implants which have hybrid properties, and the use of different broaching techniques, the classification of a very heterogenous group of implants into simple binary categories becomes increasingly difficult. A more comprehensive classification system would aid in comparison of results and better understanding of the implants’ biomechanics.We review these differing stem designs, their respective cementing techniques and geometries. We then propose a simple four-part classification system and summarize the long-term outcomes and international registry data for each respective type of cemented prosthesis.Cite this article: EFORT Open Rev 2020;5:241-252. DOI: 10.1302/2058-5241.5.190034

Prospective clinical study using radiostereometric analysis (RSA) to evaluate fixation of a modular cemented polished femoral stem.

The long-term clinical success of cemented polished tapered femoral components has been demonstrated in prospective as well as registry studies. This stem design type has also been well studied with radiostereometric analysis (RSA) and provides a standard to evaluate alternative designs of polished tapered cemented femoral components. This prospective study evaluates the subsidence of a polished cemented stem with a modular neck design utilising RSA. 26 patients were prospectively enrolled in the study and 23 were available for RSA analysis at 2 years. The average subsidence of the femoral implant was 1.1 mm (SD 0.4 mm) at 2 years post operation. There were no revisions in this group, specifically no failures of the modular stem-neck design as has been seen with other implants. The RSA subsidence pattern at 2 years of this cemented femoral stem is similar to other successful designs with long-term follow-up. The implications over time of stem neck modularity for cemented polished tapered femoral components requires further evaluation.

Cement-in-cement revision with the Exeter Short Revision Stem: A review of 50 consecutive hips

Revision of a well-fixed cemented femoral stem is technically challenging. The Exeter Short Revision Stem (SRS) was developed to facilitate cement-in-cement revision mitigating some of these challenges. We present the short to mid-term results of 50 cement-in-cement revisions performed with this implant.A retrospective review of all cement-in-cement revision with the Exeter SRS, at our institution, over a seven-year period between 2007 and 2014 was conducted. Records were assessed for radiological and clinical component loosening at greater than 12 months follow-up and for revision and complications at all time points. An Oxford Hip Score (OHS) and Numeric Rating Scale (NRS) for groin and thigh pain at rest and initial mobilisation were obtained.50 implants in 46 patients were identified. Radiographic and clinical follow-up was available for 42 and 38 implants respectively at greater than 12 months. Mean radiographic follow-up was 5.1 years and clinical 4.9 years. There was no radiographic or clinical evidence of loosening. 3 revisions were performed, one for each of recurrent dislocation, infection and stem breakage. Median OHS was 39 (IQR 12) and mean NRS for groin pain at rest and initial mobilisation was 1.7 and 1.7 respectively and NRS for thigh pain at rest and initial mobilisation was 1.3 and 1.6 respectively with mean follow-up of 6.9 years.The Exeter SRS provides a viable option for cement-in-cement stem revision, with low revision, complication and loosening rates and good patient reported outcomes at short to mid-term follow up.

Total Hip Arthroplasty in Octogenarians: A Local Retrospective Case Series

With improving healthcare, the number of Filipino octogenarians is increasing. Projected population of octogenarians as reported by the Philippine National Statistics Office will increase by 28% to 3,227,253 by year 2040 (from 2015: 912,817). This is a multicenter retrospective case series involving 24 patients (1 patient with surgery on 2 hips), with an average age at the time of surgery of 82 years old (range: 80-88 years old) who underwent total hip arthroplasty during the period 2007-2016. Indications for total hip arthroplasty included 12 cases of degenerative osteoarthritis, 8 cases of displaced femoral neck fractures, 4 cases of untreated femoral neck fractures, and 1 case of subtrochanteric fracture with hip arthritis. Of the 24 patients, 21 were females and 3 were males. Of the 25 hips, 19 were treated with cemented total hip, 5 with hybrid implants, and 1 with calcar replacing cemented femoral stem. Average follow-up was 36 months (range: 6-87 months). All patients were able to ambulate and return to premorbid function. There were no intraoperative or postoperative complications encountered. Revision rate was zero percent as of last follow-up. Clinical/functional results were assessed using the Harris Hip Scoring system. The results of this study affirm that primary total hip arthroplasty is a viable treatment option for active octogenarians with end-stage arthritis and hip fractures.

Optimal plate fixation of distal femoral fractures in the presence of a well fixed cemented hip arthroplasty femoral stem.

The requirement for lateral plate fixation in the presence of a hip arthroplasty stem is increasing, yet the optimal plate construct necessary to reduce inter-prosthetic strain and prevent subsequent fractures is unknown. Therefore, the purpose of this study was to determine the optimal position of a lateral femoral plate in relation to a femoral stem. We used 4th Generation Composite Sawbones®, a collarless polished cemented femoral stem and a broad Peri-loc™ plate with varying overlap of the stem. Each construct was subjected to torsion, axial compression and 3-point lateral bending, with the strain measured at the tip of the femoral stem and the force-to-failure recorded. In all three loading directions a plate, which extended at least two shaft diameters proximal to the tip of the stem, experienced the lowest strain ( p < 0.001). Constructs with no overlap, and particularly those with a small gap between the tip of the stem and the proximal extent of the plate experienced the highest strain ( p < 0.001). This high strain resulted in lower forces required to cause fracture in the clinically significant scenarios of femoral torsion and lateral bending. Optimal plate fixation is achieved by extending a lateral femoral plate at least two shaft diameters proximal to the tip of the stem and using a spread of proximal screws. Distal fixation increases the strain experienced at the tip of the stem and higher strains are noted the smaller the gap between the proximal extent of the femoral plate and the tip of stem.

Polished Cemented Femoral Stems Have a Lower Rate of Revision Than Matt Finished Cemented Stems in Total Hip Arthroplasty: An Analysis of 96,315 Cemented Femoral Stems

BackgroundMatt and polished femoral stems have been historically grouped together in registry assessment of the outcome of cemented femoral stems in total hip arthroplasty. This is despite differences in the mode of fixation and biomechanics of loading. The aims of this study are to compare the survivorship of polished tapered stems with matt finished cemented stems. MethodsData on primary total hip arthroplasty undertaken for a diagnosis of osteoarthritis from September 1999 to December 2014 were included from a National Joint Registry. Revision rates of the 2 different types of femoral components were compared. ResultsThere were 96,315 cemented femoral stems included, of which 82,972 were polished tapered and 13,343 matt finish. The cumulative percent revision at 14 years of polished stems was 3.6% (3.0-4.2) compared to 4.9% (4.1-5.7) for matt finish stems. Polished tapered stems had a significantly lower revision rate of femoral revision (hazard ratio 0.56, P < .001). This difference is evident in patients aged <75, and becomes apparent in the mid-term and continues to increase with time. Aseptic loosening accounts for 75% of revisions of matt finish stems compared to 20% for polished tapered stems. ConclusionAlthough both polished and matt finish stems have excellent early to mid-term results, the long-term survivorship of polished stems is significantly better, with aseptic loosening becoming an issue with matt finish stems. In the future reports of cement fixation for femoral stems may benefit from separate analysis of polished and matt finish.

Total hip arthroplasty in treating elderly femoral neck fracture with hemiplegia

Objective To investigate the clinical effects of high restrictive anti-dislocation prosthesis total hip arthroplasty (THA) in treating elderly femoral neck fracture patients with hemiplegia. Methods From June 2015 to January 2017, Forty-three elderly femoral neck fracture patients with hemiplegia were treated with CombiCup THA system. There were 15 males and 28 females with an average age of 71.5±5.6 years (60-84 years). The left side was involved in 20 cases, while the right side in 23 cases. There were 15 cases with Garden III type and 28 cases with type IV. Lower limb muscle strength grade were 20 cases in grade 3, 19 cases in grade 4, and 5 cases in grade 5. Sixteen cases walked independently before injury, while 27 of them walked with the aid of crutches. The duration between injuries to operation ranged from 2 days to 5 days. The size of the prosthesis and off-set distance were recorded by template technique pre-operation. The appropriate type of prosthesis was selected to restore the offset and to reconstruct the abductor muscle arm, according to the actual measurement in the operation and the preoperative plan. Based on the bone mineral density and medullary cavity morphology, biological or cemented femoral stem prosthesis was selected. The quality of the implant and the length of both lower limbs were evaluated by pelvic X-ray immediately after operation. The patients were followed-up at 2 weeks, 1 months, 2 months, 3 months, 6 months, 1 and 2 years. Functional exercise guidance and complications were recorded at the follow-up duration. At the last follow-up, the hip function and limb function were evaluated according to the Harris score and Fugl-Meyer motor function assessment respectively. Results Based on pelvic X-ray evaluation after operation, all prosthesis position were favorable with the average angle of acetabular abduction 45.1±2.3 degrees and the length difference of both limbs less than 5 mm (average 2.2±0.8 mm). The follow-up duration ranged from 6 to 24 months with an average of 11.2±3.5 months. There was no complication such as prosthesis dislocation and infection. Deep venous thrombosis in calf occurred in 3 patients at 2 days after operation, who underwent recanalization after thrombolysis. At the last follow-up, the average score of Harris hip function and Fugl-Meyer were 90.2±3.8 (77 to 96) and 97.1±2.5 (83 to 100), respectively. No dislocation, infection, loosening, subsidence and osteolysis phenomenon was found during the follow-up. Conclusion The elderly patients with Garden type III or IV femoral neck fractures accompanied with hemiplegia can be treated with anti-dislocation prosthesis THA. It does have the advantages of low dislocation rate and improved hemiplegic limb function. Key words: Femoral neck fractures; Hemiplegia; Aged; Arthroplasty, replacement, hip

Does using a polyethylene RM press-fit cup modify the preparation of the acetabulum and acetabular offset in primary hip arthroplasty?

IntroductionWhen performing total hip arthroplasty (THA), it is important to maintain the femoral and acetabular offsets to ensure good joint stability and to restore the function of the hip abductor muscles. In our practice, we mainly use a lateralized stem and hollow out the acetabulum to the quadrilateral plate to accommodate a press-fit polyethylene cup. However, the repercussions of this preparation method, which is driven by the cup's design, are not known. We carried out a retrospective study to assess: (1) the changes in the femoral and acetabular offset; (2) the height of the center of rotation; and (3) the repercussions on wear. HypothesisWe hypothesized there would be no significant differences between the preoperative and postoperative femoral and acetabular offsets. Patients and methodsWe reviewed 88 primary THA cases performed with the RM Pressfit™ cup that had a minimum of 5 years’ follow-up. A lateralized self-locking Muller-type cemented femoral stem was used in 92.0% of cases and a standard stem in 8.0%. Measurements were done on plain radiographs with MHP™ and Mesurim Pro™ software. The average follow-up was 6.5 years (5–8). ResultsOn average, the acetabular offset was reduced by 2.75mm±5.9 mm (range: –17.5 to +10.6 mm) (P<0.001) and the femoral offset was increased by 0.01mm±5.5 mm (range: –17.8 to +11.0 mm) (P=0.99). In terms of total offset, medialization of 2.74mm±7 mm (range: –17.7 to +18.2mm) was found (P=0.001). The acetabular center of rotation was on average 4.77mm±5.1 mm higher (P<0.001). The mean annual wear at the more recent follow-up (min.: 5 years) was 0.068mm (range: 0.01 to 0.25mm) per year. The wear was not impacted by having more than 5mm change in offset. DiscussionMeasurements of acetabular offset revealed statistically significant medialization due to the type of implant used and the surgical technique. The anatomical technique consists of positioning the cup in subchondral bone without contacting the quadrilateral plate. This preserves bone stock, which may be useful later on if the cup is revised, particularly in younger patients. Conversely, the femoral offset did not change significantly, despite the use of lateralized stems in 92.0% of cases. We measured an annual wear rate of 0.068mm per year, which is lower than in other published studies, possibly because our patient population was older. Level of evidenceIV, retrospective study.

Avaliação radiográfica da técnica de cimentação com haste femoral cônica polida e tripla cunha em artroplastia do quadril

ObjectiveTo radiographically evaluate the quality of cementation and implantation technique using a polished, triple‐tapered femoral stem in total hip arthroplasty (THA). MethodRetrospective study with radiographic evaluation of 86 hips in 83 patients who underwent to primary THA with the triple‐tapered cemented femoral stem C‐Stem (DePuy Orthopedics, Warsaw, Ind). Cases with at least one‐year of follow‐up were included, and data related to preoperative, immediate postoperative, and late postoperative radiographic evolution were recorded. This study analyzed, among others, the proximal femoral anatomy, the quality of cementation as described by Barrack, and the implant positioning. Cementation was also evaluated and quantified in the Gruen zones with one‐year of follow‐up. ResultsThe mean age was 62.85 years. Proximal femoral anatomical conformation was Dorr type A in 34 (39.53%) cases, type B in 52 (60.46%), and no type C cases were found. Five (5.81%) cases were defined as type A by Barrack's cementation classification system, 46 (56.49%) type B, 27 (31.40%) type C, and eight (9.30%) type D. The greatest cement mantle thickness was observed in zones four (15.53mm) and 11 (15.64mm), and the smallest in zone nine (3.51mm). Positioning in varus was observed in eight (9.3%) cases, valgus in 25 (29%), forward deviation in two (5%), and backward deviation in 55 (63.95%). ConclusionsThe C‐Stem femoral system presented satisfactory results related to cementation pattern, positioning, osteolysis, and stress shielding with regard to literature referring to double‐tapered or triple‐tapered models, demonstrating to be a safe method, with a predictable and reliable cementing pattern.

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

ObjectiveTo radiographically evaluate the quality of cementation and implantation technique using a polished, triple-tapered femoral stem in total hip arthroplasty (THA). MethodRetrospective study with radiographic evaluation of 86 hips in 83 patients who underwent to primary THA with the triple-tapered cemented femoral stem C-Stem (DePuy Orthopedics, Warsaw, Indiana). Cases with at least one-year of follow-up were included, and data related to preoperative, immediate postoperative, and late postoperative radiographic evolution were recorded. This study analyzed, among others, the proximal femoral anatomy, the quality of cementation as described by Barrack, and the implant positioning. Cementation was also evaluated and quantified in the Gruen zones with one-year of follow-up. ResultsThe mean age was 62.85 years. Proximal femoral anatomical conformation was Dorr type A in 34 (39.53%) cases, type B in 52 (60.46%), and no type C cases were found. Five (5.81%) cases were defined as type A by Barrack's cementation classification system, 46 (56.49%) type B, 27 (31.40%) type C, and eight (9.30%) type D. The greatest cement mantle thickness was observed in zones four (15.53mm) and 11 (15.64mm), and the smallest in zone nine (3.51mm). Positioning in varus was observed in eight (9.3%) cases, valgus in 25 (29%), forward deviation in two (5%), and backward deviation in 55 (63.95%). ConclusionsThe C-Stem femoral system presented satisfactory results related to cementation pattern, positioning, osteolysis, and stress shielding with regard to literature referring to double-tapered or triple-tapered models, demonstrating to be a safe method, with a predictable and reliable cementing pattern.

Experimental in-vitro bone cements disintegration with ultrasonic pulsating water jet for revision arthroplasty

The paper deals with the study of using the selective property of ultrasonic pulsating water jet for the disintegration of the interface created by bone cement between cemented femoral stem and trabecular bone tissue as a potential technique for revision arthroplasty. Six types of commercial bone cements based on Polymethyl Methacrylate were used for investigation. The cements were mixed using the DePuy - SmartMix® CTS / vacuum mixing bowl. Mechanical properties of hardened bone cements were determined by nanoindentation. The bone cement samples were disintegrated using the pulsating water jet technology. The water pressure varied between 8÷20 MPa. A circular nozzle with an orifice diameter of 0, 7 mm was used for water jetting. The stand-off distance from the target material was 2 mm and the traverse speed 1 mm/s. The volume of material removal and depth of created traces were measured by MicroProf FRT optical profilometer. The results positively support an assumption that pulsating water jet has a potential to be a suitable technique for the quick and safe disintegration of bone cement during revision arthroplasty.