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Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_4 | Pages 78 - 78
1 Mar 2021
Heesterbeek P Jacobs A Bovendeert F Susan S Meis J Goosen J
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Ruling out an infection in one-stage knee and hip revisions for presumed aseptic failure by conventional tissue cultures takes up to 14 days. Multiplex polymerase chain reaction (PCR) is a quick test (4–5 hours) for detecting infections. The purpose of this study was to evaluate the negative predictive value of an automated multiplex PCR for the detection of microorganisms in synovial fluid obtained intraoperatively in unsuspected knee and hip revisions. The NPV of the multiplex PCR U-ITI system of synovial fluid compared to tissue cultures of knee and hip revisions was 95.7% and 92.5%, respectively. Cultures required several days for growth whereas the automated mPCR U-ITI system provided results within five hours. The multiplex PCR U-ITI system is a quick and reliable test in ruling out infection in presumed aseptic knee and hip revisions. With this test the number of unsuspected infected revisions can be lowered and antibiotic overtreatment as well as undertreatment after one-stage revision arthroplasty can be avoided. This directly results in a reduction in length of hospital stay, hospital costs and possible antibiotic resistance development


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 110 - 110
4 Apr 2023
Ding Y Li S Li C Chen Z Wu C
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Total joint replacement (TJR) was one of the most revolutionary breakthroughs in joint surgery. The majority studies had shown that most implants could last about 25 years, anyway, there is still variation in the longevity of implants. In US, for all the hip revisions from 2012 to 2017 in the United States, 12.0% of the patients were diagnosed as aseptic loosening. Variable studies have showed that any factor that could cause a systemic or partial bone loss, might be the risk of periprosthetic osteolysis and aseptic loosening. Breast cancer is the most frequent malignancy in women, more than 2.1 million women were newly diagnosed with breast cancer, 626,679 women with breast cancer died in 2018. It's been reported that the mean incidence of THA was 0.29% for medicare population with breast cancer in USA, of which the incidence was 3.46% in Norwegian. However, the effects of breast cancer chemotherapy and hormonotherapy, such as aromatase inhibitors (AI), significantly increased the risk of osteoporosis, and had been proved to become a great threat to hip implants survival. In this case, a 46-year-old female undertook chemotherapy and hormonotherapy of breast cancer 3 years after her primary THA, was diagnosed with aseptic loosening of the hip prosthesis. Her treatment was summarized and analyzed. Breast cancer chemotherapy and hormonotherapy might be a threat to the stability of THA prosthesis. More attention should be paid when a THA paitent occurred with breast cancer. More studies about the effect of breast cancer treatments on skeleton are required


In severe cases of total knee & hip arthroplasty, where off-the-shelf implants are not suitable (i.e., in cases with extended bone defects or periprosthetic fractures), 3D-printed custom-made knee & hip revision implants out of titanium or cobalt-chromium alloy represent one of the few remaining clinical treatment options. Design verification and validation of such custom-made implants is very challenging. Therefore, a methodology was developed to support surgeons and engineers in their decision on whether a developed design is suitable for the specific case. A novel method for the pre-clinical testing of 3D-printed custom-made knee implants has been established, which relies on the biomechanical test and finite element analysis (FEA) of a comparable clinically established reference implant. The method comprises different steps, such as identification of the main potential failure mechanism, reproduction of the biomechanical test of the reference implant via FEA, identification of the maximum value of the corresponding FEA quantity of interest at the required load level, definition of this value as the acceptance criterion for the FEA of the custom-made implant, reproduction of the biomechanical test with the custom-made implant via FEA, decision making for realization or re-design based on the acceptance criterion is fulfilled or not. Exemplary cases of custom-made knee & hip implants were evaluated with this new methodology. The FEA acceptance criterion derived from the reference implants was fulfilled in both custom-made implants and subsequent biomechanical tests verified the FEA results. The suggested method allows a quantitative evaluation of the biomechanical properties of custom-made knee & hip implant without performing physical bench testing. This represents an important contribution to achieve a sustainable patient treatment in complex revision total knee & hip arthroplasty with custom-made 3D printed implants in a safe and timely manner


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_7 | Pages 8 - 8
1 Apr 2014
Bell S Anthony I Jones B Blyth M
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The number of primary Total Knee Arthroplasty (TKA) and primary Total Hip Arthroplasty (THA) procedures carried out in England and Wales is increasing annually. The British Orthopaedic Association guidelines for follow up currently differ for patients with TKA and THA. In THA the BOA recommends that Orthopaedic Data Evaluation Panel (ODEP) 10A rated implants should be followed up in the first year, once at seven years and three yearly thereafter. The BOA guidelines for TKA minimum requirement is radiographs at 5 years and each five years thereafter. Few studies have investigated if early follow up affects patient management following total hip and knee arthroplasty. We carried out a retrospective review of all revision procedures carried out in our institution between April 2010 to April 2013. The medical notes and radiographs for each patient were examined to determine the operative indications and patients symptoms. 92 knee revisions and 143 hip revisions were identified. Additionally we retrospectively reviewed the outcome of 300 one year routine arthroplasty follow up appointments. The mean time of hip revision was 8.5years (range 0 to 27years) and 5.6years (range 0 to 20years) for knee revisions. The commonest cause for revision was aseptic loosening associated with pain in 49 (53%) of knee revision patients and 89 (63%) of hip revisions. Infection accounted for 26 (28%) knee revisions and 16 (12%) hip revisions. Only 1% of hip and knee revisions was carried out in asymptomatic patients with aseptic loosening. We did not identify any cases were a patients management was altered at the routine arthroplasty review clinic and none were referred on for further surgical treatment. The findings of our study suggest there is no evidence for a routine one year arthroplasty review and revisions were carried out in asymptomatic patients in 1% of patients


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_2 | Pages 64 - 64
1 Jan 2017
Pereira J Ramos A Completo A
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Positioning of the hip resurfacing is crucial for its long term survival and is critical in young patients for some reasons; manly increase the wear in the components and change the load distribution. THR have increased in the last years, mainly in young patients between 45 to 59 years old. The resurfacing solution is indicated for young patients with good bone quality. A long term solution is required for these patients to prevent hip revision. The resurfacing prosthesis Birmingham Hip Resurfacing (BHR) was analyzed in the present study by in vitro experimental studies. This gives indications for surgeons when placing the acetabular cup. One synthetic left model of composite femur (Sawbones®, model 3403), which replicates the cadaveric femur, and four composite pelvic bones (Sawbones®, model 3405), were used to fix the commercial models of Hip resurfacing (Birmingham model). The resurfacing size was chosen according to the head size of femurs with 48 mm head diameter and a cup with 58 mm. They were introduced by an experimented surgeon with instrumental of prosthesis. The cup is a press fit system and the hip component was cemented using bone cement Simplex, Stryker Corp. The acetabular cup was analyzed in 4 orientations; in anteverion with 15º and 20°; and in inclination 40 and 45°. Combinations of these were also considered. The experimental set-up was applied according to a system previously established by Ramos et al. (2013) in the anatomic position. The femur rotates distally and the Pelvic moves vertically as model changes, such that the same boundary conditions are satisfied. This system allows compensating motions of the acetabular cup orientation. A vertical load of 1700 N was applied on all cases, which have resulted in joint reaction force of 2.4 kN. The femur and iliac bone was instrumented with rosettes. 5 repetitions at each position were conducted. When the femur was instrumented with three rosettes in medial, anterior and posterior aspect, the maximum strain magnitude was observed in the medial aspect of femur with a minimum principal strain of −2070µε for 45° inclination and 20° of anterversion. The pubic region was found most critical region after instrumenting the Iliac bone with four rosettes, with a minimum principal strain around −2500µε (rosette 1), for the 45° inclination and 20° of anterversion. We have observed the great influence of the inclination on the strain distribution, changing its magnitude from compression to traction in different bone regions. The minimum principal strain is more critical in medial aspect of the femur and the influence of strain is about 7% when orientation and inclination change. The maximum influence was observed in the anterior aspect, where the anteversion presents a significant influence. The results show the interaction between inclination and anterversion in all aspects, being observed lower values in lower angles. The orientation of the acetabular cup significantly influences the strain distribution on the iliac surface. Besides, as anterversion increases, more strains are induced, mainly in the region of iliac body (rosette 3)


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 165 - 165
1 Jul 2014
Acker A Fischer J Aminian K Martin E Jolles B
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Summary Statment. The dual-mobility cup seems to bring more stability without changing the gait pattern. Introduction. Dislocations and instability are among the worst complications after THA in elderly patient. Dual mobility cups seem to lower these risks. To our knowledge no study performed a gait analysis of dual cup in this group. Methods. Our team implanted 52 dual mobility cups (Gyros, de Puy J&J Corporation) before 2007. 7 hip revisions and 15 primary hips were reviewed in 20 patients. The mean age at the review was 79.8 years old. 15 died or were mentally too disabled to perform a gait analysis. 5 didn't give consent for a clinical study and 8 were not localizable. We performed a gait analysis using a non-invasive miniature sensors device (PhysilogTM) when patients walked freely on a flat ground. We compared our results to a control group of frail eldery patients of the same age who didn't sufferd of orthopedic condition and to a group of patient with a conventional THA from our institution and to the literature. The WOMAC and Harris Hip scores were also computed. Results. None of the 22 hips faced dislocation. The gait analysis showed good results that were superior to those of the control group of frail elderly and comparable to those of conventional THA. The cadence was of 100,3 steps/min, the double stance of 23,3%, the stance of 61,6%, the stride of 1,13 meters and the walking speed of 0,96 m/s. The mean HHS and WOMAC were 87,6 (51–100) and 11,3 (0–34). Conclusion. Our results at 5 years compared favorably with the current litterature. The increase of stability didn't impared the walking performances


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_13 | Pages 76 - 76
1 Mar 2013
Holsgrove T Petheram T Miles AW Timperley AJ
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250 words max Long polished cemented femoral stems, such as the Exeter Hip Revision stem, are one option available to the revision hip arthroplasty surgeon. When proximal bone stock is compromised, distal fixation is often relied upon for stability of the femoral component. In such circumstances, torsional forces can result in debonding and loosening. This study compared the torsional behaviour of a cemented polished and featureless (plain) stem with cemented, polished stems featuring fins or flutes. Nine torsional tests were carried out on each of these three different stem designs. The finned stem construct was significantly stiffer than the fluted stem (mean 24.5 Nm/deg v 17.5 Nm/deg). The plain stem mean stiffness was less than the featured stems (13 Nm/deg), but wide variability lead to no statistically significant difference. The maximum torque of the finned (30.5 Nm) and fluted stems (29 Nm) was significantly higher than the plain stem (10.5 Nm); with no significance to the difference between the finned and fluted stems. Distal stem features may provide a more reliable and greater resistance to torque in polished, cemented revision hip stems. Finned stem features may also increase the stiffness of the construct. Consideration should thus be given to the incorporation of distal stem features in the design of revision hip stems


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_VIII | Pages 48 - 48
1 Mar 2012
Beaulé PE
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The renewed interest in the clinically proven low wear of the metal-on-metal bearing combined with the capacity of inserting a thin walled cementless acetabular component has fostered the reintroduction of hip resurfacing. As in other forms of conservative hip surgery, i.e. pelvic osteotomies and impingement surgery, patient selection will help minimize complications and the need for early reoperation. Patient Selection and Hip Resurfacing. Although hip resurfacing was initially plagued with high failure rates, the introduction of metal on metal bearings as well as hybrid fixation has shown excellent survivorships of 97 to 99% at 4 to 5 years follow-up. However, it is important to critically look at the initial published results. In all of these series there was some form of patient selection. For example, in the Daniel and associates publications, only patients with osteoarthritis with an age less than 55 were included with 79% of patients being male. Treacy and associates stated that: “the operation was offered to men under the age of 65 years and women under the age of 60 years, with normal bone stock judged by plain radiographs and an expectation that they would return to an active lifestyle, including some sports”. However in the materials and methods, although the mean age is 52 years, the range is from 17 to 76 years including some patients with rheumatoid arthritis as well as osteonecrosis. Obviously, some form of patient selection is needed; but how one integrates them is where the Surface Arthroplasty Risk Index (SARI) is useful. With a maximum score of 6, points are assigned accordingly: femoral head cyst >1cm: 2 points; patient weight <82kg: 2 points; previous hip surgery: 1 point; UCLA Activity level >6: 1 point. A SARI score >3 represented a 4 fold increase risk in early failure or adverse radiological changes and with a survivorship of 89% at four years. The SARI index also proved to be relevant in assessing the outcome of the all cemented McMinn resurfacing implant (Corin¯, Circentester, England) at a mean follow-up of 8.7 years. Hips which had failed or with evidence of radiographic failure on the femoral side had a significantly higher SARI score than the remaining hips, 3.9 versus 1.9. Finally, one must consider the underlying diagnosis when evaluating a patient for hip resurfacing. In cases of dysplasia, acetabular deficiencies combined with the inability of inserting screws through the acetabular component may make initial implant stability unpredictable. This deformity in combination with a significant leg length discrepancy or valgus femoral neck could compromise the functional results of surface arthroplasty, and in those situations a stem type total hip replacement may provide a superior functional outcome. In respect to other diagnoses (osteonecrosis, inflammatory arthritis), initial analyses have not demonstrated any particular diagnostic group at greater risk of earlier failure. The only reservation we have is in patients with compromised renal function since metal ions generated from the metal-on-metal bearing are excreted through the urine and the lack of clearance of these ions may lead to excessive levels in the blood. Surgical Technique. Because resurfacing has not been within the training curriculum of orthopaedic surgeons for the last 2 decades, there will most likely be a learning curve in the integration of this implant within clinical practice. This data was confirmed for hip resurfacing when looking at the Canadian Academic Experience where in the first 50 cases of five arthroplasty surgeons only a 3.2% failure rate was noted of which 1.6% were due to neck fracture. Femoral neck fracture can occur because of significant varus positioning as well as osteonecrosis of the femoral head due to either disruption of the blood supply or over cement penetration. Finally, abnormal wear patterns leading to severe soft tissue reactions are being increasingly recognized and are related to either impingement or vertically placed acetabular components. Although impingement has long been recognized after total hip arthroplasty to limit range of motion and in extreme cases to hip instability, the risk after hip resurfacing may be greater since the femoral head-neck unit is preserved. Beaulé and associates have reported that 56% of hips treated by hip resurfacing have an abnormal offset ratio pre-operatively, with the two main diagnostic groups presenting deficient head-neck offset being osteonecrosis and osteoarthritis both of which have been associated with femoroacetabular impingement in the pre arthritic state. Conclusion. Although patients with a high activity level are likely to put their hip arthroplasties at risk for earlier failure, limiting a patient's activity because of fear of revision with a stem type hip arthroplasty has been shown to negatively impact the quality of life at long term follow-up. Thus hip resurfacing arthroplasty plays a significant role in the treatment of hip arthritis by permitting a return to full activities or what the patient perceives as his/her full capacities to do so, permitting them to enjoy a better quality of life without fearing a major hip revision