The next critical role of orthopedic registries Causes of early failure in a multicenter clinical trial of hip resurfacing. Outcome after total hip arthroplasty: Part II. Disease-specific follow-up and the Swedish National Total Hip Arthroplasty Register Modified direct anterior approach in minimally invasive hip hemiarthroplasty in a geriatric population: a feasibility study and description of the technique A randomised controlled trial of total hip arthroplasty versus resurfacing arthroplasty in the treatment of young patients with arthritis of the hip joint Comparison of mid-term clinical outcomes after primary total hip arthroplasty with Oxinium vs cobalt chrome femoral heads. Perioperative risk factors for deep vein thrombosis after total hip arthroplasty or total knee arthroplasty. Early functional results after Hemiarthroplasty for femoral neck fracture: a randomized comparison between a minimal invasive and a conventional approach Clinical and radiological short-term complications after single-stage bilateral uncemented total hip arthroplasty Primary Total Hip Arthroplasty with a Porous-Coated Acetabular Component. Seven-to-Ten-Year Results* [Advantages of minimal invasive total hip replacement in the early phase of rehabilitation]. Immediate weight bearing after uncemented total hip arthroplasty with an anteverted stem: A prospective randomized comparison using radiostereometry Persistent non-specific FDG uptake on PET imaging following hip arthroplasty Patient-matched instruments versus standard instrumentation in total knee arthroplasty: a prospective randomized study Bone remodelling around the Metha short stem in total hip arthroplasty: a prospective dual-energy X-ray absorptiometry study Primary total hip arthroplasty with a proximally porous-coated femoral stem. Robot‐assisted total hip arthroplasty: Clinical outcomes and complication rate
There is an urgent need for the introduction of new implant technology in orthopedic surgery to be conducted in a more controlled manner than in the past . Inadequate regulation and lack of effective post-market surveillance have meant that patients have not been protected from potentially harmful implants and procedures . Compounding the problem is a lack of question ing , a lack of critical appraisal , and lack of a requirement for clinical evidence by both surgeons and manufacturers before large-scale introduction of new technology to the market . There is a long and growing history of failed innovation , demonstrated by the failure or recall of individual products such as Boneloc ( bone cement ) , The Capital Hip ( total hip arthroplasty ) , and the ASR hip system ( total hip arthroplasty ) among others , as well as whole classes of devices such as large-head metal-on-metal bearings . This demonstrates simple , yet severe flaws in the mechanisms that should protect patients from increased risk associated with introduction of new technology . Insufficient or inadequate pre clinical data , a lack of clinical data from timely RSA ( radiostereometric analysis ) studies , and limited larger , multicenter cohort studies prior to general release all increase the risk to patients . The 510k process , where the majority of so-called innovative new design s have been cleared or approved by FDA - or CE-notified bodies for clinical use , is based on similarities to previously used implants . In the 510k process , there is no requirement for specific clinical evidence , so manufactures have not obtained clinical data . Registry post-market surveillance has proven to be a powerful method for detection of increased risk of implant failure , but this is not available in all countries . When registries do identify poor-performing devices , regulators and manufacturers are often slow to respond . The main problem with the current approach to the introduction of new technology is the inability to identify unanticipated failures before wider release ( Bauer 1992 ) . It is 20 years since the stepwise introduction of new implants was first described ( Malchau 1995 ) . The basic concept of this approach is that the smallest possible numbers of patients ( after sufficient pre clinical testing ) are exposed to the implant prior to general release . Stepwise introduction uses a combination of ( 1 ) outcome measurements with high-precision metrics in small cohorts , such as RSA , and ( 2 ) limited clinical introduction in a larger cohort , prospect ively monitoring outcomes and revisions . Adoption of this concept would certainly have reduced the large number of poor-performing new implants introduced in recent years . The concept has , however , never been implemented due to lack of support from surgeons , manufacturers , and regulatory authorities . Now trends have changed , with increasing focus on implementing an effective approach to pre-release clinical assessment . The ongoing work and discussion s in the International Society of Arthroplasty Registries ( ISAR ) , the reports from the Australian Orthopaedic Association total joint registry , and the actions taken in the UK to put a “ beyond compliance ” program into action will facilitate a more cautious market introduction . In addition , the Arthroplastywatch project ( www.arthroplastywatch.com ) is in action : data are collected on the web through a specially developed search routine . Based on examination in several steps using medical and statistical expertise , a caution could be warranted or a warning declared . These combined initiatives say one thing : that close monitoring of new implants by well-established registries during a phase of controlled introduction must be a universal requirement . We propose a structured model for clinical trials involving 4 levels : ( 1 ) a pure observational study using reoperation data from multiple registries , as shown in several papers by the Nordic Arthroplasty Register Association ( NARA ) ; ( 2 ) patient-reported outcome measures , either from national implant registries or from other registries for specific studies ; ( 3 ) radiographic data plus other parameters such as blood levels of metal ions , based on specific needs for a new technology ; and ( 4 ) options for r and omized studies with use of , for example , RSA in the evaluation . The cornerstone in this structural model should be the exp and ed use of existing and future registries with a high degree of coverage and completeness . While registries have a strong tradition in arthroplasty surgery , this is not as well developed in other areas of orthopedic surgery . It is the responsibility of orthopedic surgeons and their professional bodies to support and implement registries where they can be of benefit . The arthroplasty registry experience has shown that it is possible to use registries to effectively monitor the introduction of new technology . Without this registry-based surveillance , identification of many of the failed innovations would have been delayed or might even have gone unrecognized . It is encouraging that registries in fracture surgery are now emerging , where implants are inserted in large and increasing numbers . Finally , implant performance is potentially confounded by the technical difficulty of inserting the implant , the knowledge and abilities of the surgeon inserting them , and the complexity of the cases . Many registries monitor performance at the surgeon level . This together with continuous education and training in how to use new implants should be an integral part of the process of a more cautious market introduction . If training is linked in with the stepwise introduction , it will be possible to identify the need for and the extent of training . Our proposed regulatory change to require registry-based monitoring of new implants during the phase of limited introduction must be accompanied by a change in the way we think and act as orthopedic surgeons . In the training of future orthopedic surgeons , emphasis must be placed on developing a healthy skepticism to innovation , on recognizing the need for evidence -based introduction , and on building a culture holding the view that reporting to a registry is imperative . The registries will then be able to offer back data to enable surgeons to choose the best clinical practice . To increase innovation and to ensure that innovation is effective and beneficial , the role of registries should be exp and ed . The registries should not undertake the role of a regulatory authority , but in compliance with the industry and the orthopedic community they should ensure that a more cautious approach is used when new technology is introduced . This could lead to a better balance between the inborn conservatism that a registry represents and the continuous need for innovation . The independence , infrastructure , and expertise of the registries can be used more fully to optimize how new implants are introduced . All stakeholders need to join to ensure that first and foremost , we do no harm The purpose of this study was to evaluate the clinical outcomes and possible causes of early failure in a multicenter trial of metal-on-metal hip resurfacing . Two hundred patients were prospect ively enrolled and followed for an average of 31.2 months ( range , 12 - 54 months ) . Of 200 patients , 14 ( 7.0 % ) required revision surgery at a mean time of 19.5 months ( range , 3 - 47 months ) . Patients with failures were significantly younger and heavier than the nonfailures , and all were male . Patients who were revised did not differ from those who were not revised in terms of radiographic outcomes , but they did report lower functional outcome scores at all preoperative and postoperative testing intervals . Most failures ( 10/14 ) were related to early acetabular loosening . The learning curve was likely a factor in these cup failures . This report highlights the importance of patient selection and surgical technique in hip resurfacing arthroplasty . It is anticipated that further surgical experience will lead to a reduction in this high early failure rate The Swedish National Total Hip Arthroplasty Register records primary hip replacements , revisions and surgical technique/environmental factors . The end-point for failure is revision . A prosthesis still in place , however , does not mean success . Clinical and radiographic outcomes should describe in more detail the efficacy of hip replacement surgery instead of the relatively blunt outcome measure that the register can provide . We performed a clinical outcome analysis on patients with primary total hip replacement thus testing the adequacy of the end-point for failure in the Swedish register . 1,113 r and omly selected patients who had had total hip replacement surgery between 1986 and 1995 answered a diseasespecific self-administered question naire ( WOMAC ) . A cohort of 344 patients was studied , using the  Harris Hip Score and a conventional radiographic examination  as outcome measures . We found clinical failure rates of 13 % and 20 % for all implants after 10 years , using 60 points or revision as the definition of failure in the Harris Hip Score and WOMAC , respectively . The result , according to the register during the same period , was a 7 % revision rate . The clinical failure rate depended on the type of evaluation tool , definition of failure and demographics , which made it difficult to decide whether there was a need for revision . With the exception of pain measured by the Harris Hip Score , the results showed no significant correlation between clinical failure and radiographic failure . Hence , with the knowledge that there is a difference between the revision rate according to the register and clinical outcome , the strict definition of failure in the register is useful as an end-point for primary hip replacement surgery Introduction The direct anterior approach ( DAA ) is generally accepted method for minimal invasive arthroplasty of the hip . As good results for total hip arthroplasty are already published , there is a lack of evidence for the implantation of bipolar hip hemiarthroplasty ( BHH ) in elderly patients with osteoporosis after femoral neck fracture . Material s and methods For hip arthroplasty using a direct anterior approach ( DAA ) in elderly patients with femoral neck fractures , a number of modifications of the original technique are being described . The modified DAA considers in particular the co-morbidity and the bone quality of the geriatric patient population . A consecutive series of 16 hemiarthroplasties using this technique is presented . In all 16 cases , the BHH was implanted in modified DAA technique . Mobility measured by 4-item Barthel Index , pain via visual analogue scale ( VAS ) , duration of surgery , external length of incision and blood loss were evaluated . Results There was no major operative complication during the procedures . The pain level decreased from 7 ( preoperatively ) to 0 at postoperative day 40 . The Barthel Index increased from 5 at first postoperative day to 40 at day 40 . Early postoperative mobilisation is efficiently accelerated . Mean operating time was 71 min ; the medium skin incision length was 8 cm . The mean haemoglobin level decreased from 118 g/dl preoperatively to 101 g/dl at first postoperative day . Conclusion The described modifications of the DAA help to implant a BHH gently in elderly patients with increasing risk of complications like iatrogenic fractures , wound or prosthesis infections and haematoma . This will hopefully lead to a faster rehabilitation and lower mortality rate for patients with femoral neck fractures in the future Background Hip replacement ( arthroplasty ) surgery is a highly successful treatment for patients with severe symptomatic arthritis of the hip joint . For older patients , several design s of Total Hip Arthroplasty have shown excellent results in terms of both function and value for money . However , in younger more active patients , there is approximately a 50 % failure rate at 25 years for traditional implants . Hip resurfacing is a relatively new arthroplasty technique . In a recent review of the literature on resurfacing arthroplasty it was concluded that the short-term functional results appear promising but some potential early disadvantages were identified , including the risk of femoral neck fracture and collapse of the head of the femur . The aim of the current study is to assess whether there is a difference in functional hip scores at one year post-operation between Total Hip Arthroplasty and Resurfacing Arthroplasty . Secondary aims include assessment of complication rates for both procedures as well cost effectiveness . Methods / design All patients medically fit for surgery and deemed suitable for a resurfacing arthroplasty are eligible to take part in this study . A r and omisation sequence will be produced and administered independently . After consenting , all patients will be clinical ly review ed and hip function , quality of life and physical activity level will be assessed through question naires . The allocated surgery will then be performed with the preferred technique of the surgeon . Six weeks post-operation hip function will be assessed and complications recorded . Three , six and 12 months post-operation hip function , quality of life and physical activity level will be assessed . Additional information about patients ' out-of-pocket expenses will also be collected . Trial registration Current Controlled Trials IS RCT N33354155UKCLRN portfolio ID The purpose of this investigation was to assess the midterm clinical outcomes after implantation of Oxinium ( OX ) vs cobalt-chrome ( CC ) femoral heads .  Primary total hip arthroplasty ( THA ) procedures were performed in 100 patients . After r and omization , half of the patients received OX femoral heads and half received CC femoral heads . At a minimum follow-up of 2-years , stem survival was 98 % for both groups . The mean Harris Hip score was 92 for OX and 92.5 for CC , with mean WOMAC scores of 84.9 and 87 , respectively . For SF-12 , the OX group had mean physical and mental component scores of 45.2 and 53.8 and the CC group 49.2 and 52.6 , respectively . At a minimum follow-up of 2 years , clinical outcomes for THA procedures using OX and CC femoral heads appear equivalent STUDY OBJECTIVE To determine the perioperative frequency of  deep vein thrombosis ( DVT ) after lower limb joint prosthesis surgery using Doppler ultrasonography ( US ) . DESIGN Prospect i ve cohort study . SETTING Operating room and hospital ward . PATIENTS 144 consecutive ASA physical status 1 and 2 patients who underwent elective total hip arthroplasty ( THA ; n=64 ) or total knee arthroplasty ( TKA ; n= 80 ) . INTERVENTIONS Patients were allocated to two groups , those who developed DVT ( DVT group ) postoperatively and those who did not ( no-DVT group ) . To examine the perioperative risk factors for DVT after THA or TKA , comparative analysis of the two groups was done . MEASUREMENTS Doppler US was performed on all patients from the bilateral femoral to lower limb to detect the existence of DVT postoperatively . MAIN RESULTS DVT was detected in 61 patients ( 42 % ) , including three proximal DVT patients ( 2 % ) . Preoperative elevated plasma D-dimer value [ P = 0.0131 , odds ratio ( OR ) 1.54 , 95 % CI 1.10 - 2.17 ] and history of hyperlipidemia ( P = 0.0453 , OR 6.92 , 95 % CI 1.04 - 46.00 ] were significant risk factors for the onset of DVT . A preoperative plasma D-dimer cutoff value as a diagnostic test was obtained as 0.85 μg/mL. CONCLUSIONS A high preoperative plasma D-dimer value and /or history of hyperlipidemia were risk factors for DVT after THA or TKA Background A minimal invasive approach for elective hip surgery has been implemented in our institution in the past . It is widely hypothesized that implanting artificial hips in a minimal invasive fashion decreases surgical trauma and is helpful in the rehabilitation process in elective hip surgery . Thereby geriatric patients requiring emergency hip surgery also could theoretically benefit from a procedure that involves less tissue trauma . Methods Sixty patients who sustained a fractured neck of femur were r and omly assigned into two groups . In the minimal invasive arm , the so called “ direct anterior approach ” ( DAA ) was chosen , in the conventional arm the Watson-Jones-Approach was used for implantation of a bipolar hemi-arthroplasty . Primary outcome parameter was the mobility as measured by the four-item-Barthel index . Secondary outcome parameters included pain , haemoglobin-levels , complications , duration of surgery , administration of blood transfusion and external length of incision . Radiographs were evaluated . Results A statistically significant difference ( p = 0,009 ) regarding the mobility as measured with the four-item Barthel index was found at the 5th postoperative day , favouring the DAA . Evaluation of the intensity of pain with a visual analogue scale ( VAS ) showed a statistically significant difference ( p = 0,035 ) at day 16 . No difference was evident in the comparison of radiographic results . Conclusions Comparing two different approaches to the hip joint for the implantation of a bipolar hemi-arthroplasty after fractured neck of femur , it can be stated that mobilization status is improved for the DAA compared to the WJA when measured by the four-item Barthel index , there is less pain as measured using the VAS . There is no radiographic evidence that a minimal invasive technique leads to inferior implant position . Level of Evidence : Level II therapeutic study Abstract Purpose Economic crisis time gives to efficient procedures an important role in healthy system . Total hip replacement is a common bilateral orthopedic procedure , but there exists an important controversy to perform it in single or two stages . Our aim is to report our clinical and radiological short-term complications of bilateral uncemented total hip arthroplasty in a single time . Material s and methods We have retrospectively review ed the patients treated between 2000 and 2011 in our center by bilateral uncemented total hip replacement in a single time .  We have review ed the medical history and analyzed by age , diagnosis and ASA parameters related to the procedure , hospital stay , transfusion requirements and clinical complications . Radiological evaluation was made with anteroposterior hip radiograph evaluation ( acetabular radiolucencies and stem migration ) . Functional assessment was carried out by the Merle D’Aubigné score . Results Seventeen patients with mean age of 47.4 ( 18–68 ) years were review ed with a mean follow-up of 44.3 ( 6–172 ) months . ASA distribution : 29.4 % grade I ; 52.9 % grade II and 17.6 % grade III . Merlé D’Aubigné score improved from 11.01 to 16.45 . Hospital stay was 6 days . Transfusion requirements were two hematic concentrates for each patient . Two external popliteal sciatic nerve neurapraxias fully recovered at follow-up . Radiological results showed one case of axial migration . Conclusions With proper patient selection and multidisciplinary team , the bilateral uncemented total hip arthroplasty in a single time has low complication rates . Our results could be used in the development of future r and omized controlled trials or prospect i ve cohort studies .Level of evidence IV One hundred and eighty-four patients who had been managed , between 1984 and 1985 , with a total of 204 consecutive primary total hip arthroplasties with insertion of a Harris-Galante type-I acetabular component without cement were prospect ively studied . There were eighty-two men ( 45 per cent ) and 102 women ( 55 per cent ) . The mean age at the time of the operation was fifty-two years ( range , twenty to eighty-four years ) . One hundred and fifty-seven patients ( 173 hips ) were available for clinical review at a mean of 104 months ( range , seventy-eight to 126 months ) . At this time , the mean preoperative Harris hip score of 52 points ( range , 12 to 79 points ) had improved to a mean of 90 points ( range , 44 to 100 points ) . Two patients ( two hips ) had had an exchange of an excessively worn polyethylene liner . One patient ( one hip ) had had débridement and grafting of an area of massive retroacetabular osteolysis . Two stable acetabular components ( 1 per cent ) had been revised at the time of femoral revision . None of the cups had been revised because of aseptic loosening . Radiographic examination of 150 patients ( 165 hips ) at a mean of 104 months ( range , seventy-eight to 126 months ) revealed that 156 cups ( 95 per cent ) were stable . Eight cups ( 5 per cent ) were considered to be possibly unstable , with a radiolucent line between the prosthesis and the bone that was one millimeter wide or less in at least four of five zones ; two of the eight had a complete radiolucent line in all zones . One component , which had been implanted with a bulk allograft from a femoral head , migrated more than two millimeters in the first two years and then stabilized without complication . Osteolysis was seen in seven acetabula ( 4 per cent ) and was limited to the periphery of the cup in six . Survivorship analysis at ten years revealed that the acetabular component had a 99 per cent chance of survival ( 95 per cent confidence interval , 0.98 to 1.0 ) with revision or aseptic loosening as the end point and a 97 per cent chance of survival ( 95 per cent confidence interval , 0.95 to 1.0 ) with revision , aseptic loosening , or reoperation because of a problem related to the acetabular component as the end point UNLABELLED In arthroplasty the term " minimal invasive " not only refers to the length of the skin incision but more so to its soft tissue and thereby muscle-protecting features . STUDY AIM The aim of this study is to compare the early postoperative mobilisation and rehabilitation of the different surgical approaches in cementless total hip arthroplasty . METHODS 27 patients underwent a total hip replacement ( Trilogy cup , MAYO stem ) via a ventral minimal invasive approach ( one incision technique ) ( MIS group ) . 23 patients underwent a total hip replacement with the same implant via a anterolateral transgluteal approach ( st and ard group ) . We evaluated the Harris Hip Score ( HHS ) , the visual analogue scale ( VAS ) for pain and patient satisfaction preoperatively as well as 3 days , 10 days , 6 weeks and 3 months postoperatively . RESULTS After 3 and 10 days the MIS group showed better scores for pain , gait and mobilisation as well as for the overall HHS compared to the st and ard group . These differences could not be shown 6 weeks postoperatively . The MIS group had a significantly higher rate of complications with 22 % transient impairment of the lateral cutaneous nerve . CONCLUSION The patients of the MIS group showed a better mobilisation and rehabilitation during the early postoperative period . This can be attributed to the lessened intraoperative damage of to soft tissue and especially muscle damage . Due to the increased rate of nerve irritations , we modified our surgical approach . The minimal invasive approach to modern hip joint arthroplasty remains a non-st and ard technique . Compared to the st and ard approach it carries additional risks ( like nerve damage and malpositioning of the implants and thus should remain in the h and s of the experienced orthopaedic surgeon in specialised orthopaedic centres Background In uncemented total hip arthroplasty with hydroxyapatite coating , early weight bearing is frequently practice d but there is still not much evidence to support this recommendation . Method In a prospect i ve r and omized study we evaluated the effect of partial and full weight bearing after  cementless total hip arthroplasty ( ABG ; Stryker-Howmedica ) using radiostereometric analysis ( RSA ) . Between February 1996 and February 2000 , 43 consecutive patients ( mean age 53 ( 41–63 ) years , 23 women ) with hip osteoarthrosis received an uncemented and hydroxyapatite-coated prosthesis with an anteverted stem . All patients were operated in a st and ardized way by three experienced surgeons and they were r and omized to partial ( P ) or full ( F ) weight bearing during the first 6 weeks after surgery . The patients in the partial weight bearing group were equipped with a pressuresensitive insole signaling when their load exceeded the prescribed weight limit . Results At 3-month follow-up , the mean proximal (+)/ distal ( - ) migration of the stem was -0.14 mm ( -1.93– 0.11 ) in group P and -0.31 mm ( -4.30–0.16 ) in group F ( p = 0.6 ) . At 1-year follow-up , the mean migration was –0.17 mm ( -2.18–0.21 ) and -0.28 mm ( -4.31–0.11 ) , respectively ( p = 0.9 ) . There was no significant difference in stem rotations either ( p < 0.2 ) . The cup translations , rotations , and femoral head penetration were similar in the two groups ( p < 0.1 ) . There were no re-operations during the first year . Interpretation We did not find any adverse effect of full weight bearing immediately after operation , which justifies use of this regimen after uncemented total hip arthroplasty of the ABG type Abstract . Hip arthroplasty is a common surgical procedure , but the diagnosis of infection associated with hip arthroplasty remains challenging . Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography ( FDG-PET ) has been shown to be a promising imaging modality in setting s where infection is suspected . However , inflammatory reaction to surgery can result in increased FDG uptake at various anatomic locations , which may erroneously be interpreted as sites of infection . The purpose of this study was to assess the patterns and time course of FDG accumulation following total hip replacement over an extended period of time . Firstly , in a prospect i ve study nine patients with total hip replacement were investigated to determine the patterns of FDG uptake over time . Three FDG-PET scans were performed in each patient at about 3 , 6 and 12 months post arthroplasty . Secondly , in a retrospective analysis , the medical and surgical history and FDG-PET imaging results of 710 patients who had undergone whole-body scans for the evaluation of possible malignant disorders were review ed . The history of arthroplasty and FDG-PET findings in the hip region were review ed for this study . Patients with symptomatic arthroplasties or related complaints during FDG-PET scanning were excluded from the analysis . During the entire study period , all nine patients enrolled in the prospect i ve study were demonstrated to have increased FDG uptake around the femoral head or neck portion of the prosthesis that extended to the soft tissues surrounding the femur . Among the patients review ed in the retrospective study , 18 patients with a history of 21 hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the criteria for inclusion . The time interval between the hip arthroplasty and the FDG-PET study ranged from 3 months to 288 months ( mean±SD : 80.4±86.2 months ) . In 81 % ( 17 of 21 ) of these prostheses , increased FDG uptake could be noted around the femoral head or neck portion of the prosthesis . The average time interval between arthroplasty and FDG-PET scan in these patients was 71.3 months . In only four prostheses ( 19 % , 4 of 21 ) was no abnormally increased FDG uptake seen around the prostheses or adjacent sites . The average time interval in these patients was 114.8 months . It is concluded that following hip arthroplasty , non-specifically increased FDG uptake around the head or neck of the prosthesis persists for many years , even in patients without any complications . Therefore , to minimize the number of false-positive results for infection with PET studies obtained to evaluate a painful hip prosthesis , caution should be exercised when interpreting FDG uptake around the head or neck portion of the prosthesis Summary Background Optimal positioning of implants and restoration of neutral mechanical axis are two primary surgical goals in total knee arthroplasty ( TKA ) . Despite modern instruments and improved surgical techniques , malalignment remains an important cause of early failure after TKA . The aim of this prospect i ve r and omized study was to compare the value of a new patient-matched instrument system ( PMI ) ( SignatureTM ; Biomet , Inc , Warsaw , Indiana ) to that of st and ard TKA surgical instrumentation ( STD ) in terms of coronal mechanical alignment , time of operation and blood loss . Patients and methods A total of 38 patients waiting for primary TKA were enrolled and r and omized into two groups ( 19 PMI and 19 STD ) . Magnetic resonance imaging was performed in all patients in the PMI group , and specific instruments for the femur and tibia were design ed preoperatively . All patients were operated on using the st and ard medial parapatellar approach with no use of tourniquet . Mechanical axis , time for the operation , and blood loss were evaluated . Results Patients in both groups had comparable age , body mass index , preoperative mechanical axis , Knee Society Score , and level of hemoglobin . Postoperative results showed that the PMI group fell significantly closer to neutral mechanical axis ( STD : 2.7 ± 1.7 , PMI : 1.7 ± 0.9 ; P = 0.013 ) with no outliers and a reduced time for the operation . There was no difference in the evaluation blood loss . Conclusions The use of PMI can contribute in achieving better mechanical axis with reduction in outliers and decreased operation time . Due to small differences between PMI and st and ard instruments , additional research are needed to confirm these preliminary results , and to discover potential benefits and functional improvements in the long-term outcome Purpose On the basis of positive clinical results with mid- and long-term follow-up using the Mayo short stem , the Metha neck-preserving stem ( BBraun , Aesculap , Tuttlingen , Germany ) was introduced . The purpose of this study was to vali date the implant design by direct acquisition of bone remodelling data from total hip arthroplasty ( THA ) recipients using dual-energy X-ray absorptiometry ( DEXA ) . Methods After power analysis , 25 patients were included in this prospect i ve study . Patients were examined clinical ly and underwent DEXA examinations preoperatively and postoperatively at one week , six months and one and two years after THA . Gruen zones were adapted to the short stem design ( R1–R7 ) . Results The Harris Hip Score ( HHS ) increased significantly by 31 points . No stem had to be revised . Bone mineral density ( BMD ) in the greater trochanter decreased significantly from 0.78 g/cm2 postoperatively to 0.72 g/cm2 two years after surgery . Marginal changes were seen in the lateral distal regions ( R4–R5 ) . In the minor trochanter region , BMD increased significantly after two years by 12.9 % . In the calcar region , BMD exceeded the baseline value by 6.1 % two years after implantation . Conclusions Stress shielding seems to occur at the greater trochanter due to the vast cross-section of the implant . However , the aim of proximal load transfer of the Metha stem seems to be partially achieved . DEXA analysis revealed a concentrated load distribution on the medial portion of the femur , which is an important region to guarantee long-term implant survival BACKGROUND The use of cementless , proximally porous-coated femoral stems for total hip arthroplasty has increased in popularity . The purpose of the present report was to examine the five to ten-year results associated with the use of a so-called second-generation circumferentially proximally porous-coated titanium-alloy stem . METHODS Between 1991 and 1994 , 123 Harris-Galante Multilock femoral stems were implanted in 101 patients . The average age of the patients at the time of surgery was 53.8 years . The patients were followed prospect ively and were reevaluated at a minimum of five years postoperatively . No patient was lost to follow-up . Twenty-five patients ( thirty hips ) were interviewed by telephone , and four patients ( five hips ) died during the study period because of problems that were unrelated to the operation . The remaining seventy-two patients ( eighty-eight hips ) had a minimum of five years of clinical and radiographic follow-up . RESULTS The average duration of follow-up was seventy-eight months . At the time of the most recent follow-up , the average Harris Hip Score was 95 points . Eighty-seven ( 99 % ) of eighty-eight stems were biologically stable , with eighty-four hips ( 95 % ) having osseous ingrowth and three hips ( 3 % ) having stable fibrous fixation . One stem was revised because of loosening . Thirty-three hips ( 38 % ) had minimal proximal osteolysis , and no hip had diaphyseal osteolysis . Seventy-two hips ( 82 % ) had some degree of stress-shielding in the proximal metaphysis , but only two hips had cortical resorption . None of these patients required additional surgery , and all reported a satisfactory outcome . CONCLUSIONS Given the young age and high activity level of these patients , this stem fared well : the levels of patient function and satisfaction were high , the rates of loosening and revision were very low , and distal osteolysis did not occur . Osseous fixation occurred reliably . Proximal stress-shielding was seen but did not seem to be clinical ly important BACKGROUND The purpose of this study was to report minimum 2-year outcomes and complications for robotic-arm-assisted total hip arthroplasty ( THA )  . METHODS Data were prospect ively collected and retrospectively review ed between June 2011 and April 2014 . Inclusion criteria were primary robotic-arm-assisted THAs treating idiopathic osteoarthritis with ≥ 2-year follow-up .  Demographics , operating time , complications , 2-year outcome scores and satisfaction , and subsequent surgeries were recorded . RESULTS There were 181 cases eligible for inclusion , of which 162 ( 89.5 % ) had minimum 2-year follow-up . At the latest follow-up , the mean visual analogue scale was 0.7 , satisfaction was 9.3 , Harris hip score was 91.1 and forgotten joint score was 83.1 . Six ( 3.7 % ) intraoperative complications and six ( 3.7 % ) postoperative complications were reported . No leg length discrepancies ( LLDs ) or dislocations were reported . CONCLUSIONS Robotic-arm-assisted THA demonstrates favourable short-term outcomes and does not result in a higher complication rate compared to non-robotic THA as reported by the literature
Patient Reported Outcome Measures ( PROMs ) at six months have been investigated but have not been vali date d against long-term outcomes .
EBRA can be used to investigate acetabular wear but not femoral migration .
OBJECTIVES High failure rates of metal-on-metal hip arthroplasty implants  have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices .
The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage .
We aim ed to identify vali date d surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty ( THA ) .