Roles of combined femoral and acetabular anteversion in pathological changes of hip dysplasia and hip reconstructive surgery

Combined femoral and acetabular anteversion is the sum of femoral and acetabular anteversion,representing their morphological relationship in the axial plane.Along with the increasing understanding of hip dysplasia in recent years,numerous scholars have confirmed the role of combined femoral and acetabular anteversion in the pathological changes of hip dysplasia.At present,the reconstructive surgery for hip dysplasia includes total hip replacement and redirectional hip preservation surgery.As an important surgery index,combined femoral and acetabular anteversion have a crucial role in these surgeries.Herein,we discuss the role of combined femoral and acetabular anteversion in pathological changes of hip dysplasia,total hip replacement,and redirectional hip preservation surgery.

Investigation of contact behavior on a model of the dual-mobility artificial hip joint for Asians in different inner liner thicknesses

BACKGROUND The four components that make up the current dual-mobility artificial hip joint design are the femoral head,the inner liner,the outer liner as a metal cover to prevent wear,and the acetabular cup.The acetabular cup and the outer liner were constructed of 316L stainless steel.At the same time,the inner liner was made of ultra-high-molecular-weight polyethylene(UHMWPE).As this new dual-mobility artificial hip joint has not been researched extensively,more tribological research is needed to predict wear.The thickness of the inner liner is a significant component to consider when calculating the contact pressure.AIM To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint,with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip joint.METHODS In this study,the size of the femoral head was compared between two diameters(28 mm and 36 mm)and eight inner liner thicknesses ranging from 5 mm to 12 mm.Using the finite element method,the contact parameters,including the maximum contact pressure and contact area,have been evaluated in light of the Hertzian contact theory.The simulation was performed statically with dissipated energy and asymmetric behavior.The types of interaction were surface-to-surface contact and normal contact behavior.RESULTS The maximum contact pressures in the inner liner(UHMWPE)at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa,respectively.The maximum von Mises of the inner liner,outer liner,and acetabular cup are 2.4–11.4 MPa,15.7–44.3 MPa,and 3.7–12.6 MPa,respectively,for 28 mm head.Then the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner,9.9-32.8 MPa for the outer liner,and 2.6-9.9 MPa for the acetabular cup.A head with a diameter of 28 mm should have an inner liner with a thickness of 12 mm.Whereas the head diameter was 36 mm,an inner liner thickness of 8 mm was suitable.CONCLUSION The contact pressures and von Mises stresses generated during this research can potentially be exploited in estimating the wear of dual-mobility artificial hip joints in general.Contact pressure and von Mises stress reduce with an increasing head diameter and inner liner’s thickness.Present findings would become one of the references for orthopedic surgery for choosing suitable bearing geometric parameter of hip implant.

Use of Image processing software in Hip Joint surgery

The scope of this project was to investigate the possibility of application of Image Processing Technique in the field of Shaft Alignment process. Misalignment of shaft using image processing software Visionbuilder was calculated. The further purpose of this project was to check whether the image processing technique can be used in bone transplant surgery. The model of the hip was used for the experimentation purpose. Image processing software Visionbuilder was used to match the profiles of the bone before implant and bone after implant.

Characterisation of wear particles from biomedical carbon/carbon composites with different preforms in hip joint simulator

A hip joint simulator was employed to predict the clinical wear behaviour of carbon/carbon （C/C） composites with needled carbon cloth preform and carbon felt preform. Wear particles generated from the two kinds of C/C composites were isolated and characterised by the size distribution and morphology. The evolvement of wear particles in the hip joint simulator was proposed. The results show that the wear particles from two kinds of C/C composites have a size ranging from submicron to tens of micrometers. The wear particles have various morphologies including broken fiber, fragment fiber, slice pyrolytic carbon and spherical pyrolytic carbon. C/C composites with needled carbon cloth preforms have larger size range and more broken fiber particles and slice pyrolytic carbon particles in comparison with C/C composites with carbon felt preforms. The evolvement of pyrolytic carbon particles is caused by surface regularization, whereas, the evolvement of carbon fiber particles is related to stress direction in the hip joint simulator.

Association between preoperative high sensitive troponin I levels and cardiovascular events after hip fracture surgery in the elderly

Objective Cardiovascular complications contribute to postoperative morbidity and mortality in elderly hip fracture patients. Limited data are available regarding which preoperative risk factors predict cardiovascular course following hip fracture surgery （HFS）. We used high sensitive troponin I （hs-TnI） assays and clinical parameters to identify preoperative risk factors associated with major adverse cardiac events （MACE） in elderly hip frac^u＇e patients. Method From August 2014 to November 2016, 575 patients with hip fracture were enrolled in a retrospective, single-center registry. A total of 262 of these patients underwent HFS and hs-TnI assays. MACE was defined as postoperative all-cause deaths, heart failure （HF）, new-onset atrial fibrillation （AF）, myocardial infarction （MI） and cardiovascular re-hospitalization that occurred within 90 days postoperative. Results Of 262 HFS patients, MACE developed following HFS in 65 （24.8%）. Patients with MACE were older and had higher rates of renal insufficiency, coronary artery disease, prior HF, low left ventricular ejection fraction and use of beta blockers; higher levels of hs-Tnl and N-terminal pro-brain natriuretic peptide （NT-proBNP） and higher revised cardiac risk index. A preoperative hs-TnI≥ 6.5 ng/L was associated with high risk of postoperative HF, new-onset AF and MACE. In multivariable analysis, pre-operative independent predictors for MACE were age 〉 80 years [adjusted hazard ratio （HR）： 1.79, 95% confident interval （CI）： 1.03-3.13, P = 0.04], left ventricular ejection fraction （LVEF） 〈 50% （adjusted HR： 3.17, 95% CI： 1.47-5.82, P 〈 0.01） and hs-TnI 〉 6.5 ng/L （adjusted HR： 3.75, 95% CI： 2.09~5.17, P 〈 0.01）. Conclusion In elderly patients with hip fracture who undergo HFS, a preoperative assessment of hs-TnI may help the risk refinement of cardiovascular complications.

Can periprosthetic hip joint infections be successfully managed by debridement and prosthesis retention?

To evaluate the current literature about how successfully periprosthetic hip joint infections can be managed by debridement and prosthesis retention.A literature search was performed through Pub Med until September 2013.Search terms were"DAIR(debridement,antibiotics,irrigation,and retention)"alone and in combination with"hip"as well as"hip infection+prosthesis retention".A total of 11 studies reporting on 292 cases could be identified.Five different treatment modalities have been described with varying success rates(debridement-21%infection eradication rate;debridement+lavage-75%infection eradication rate;debridement,lavage,with change of modular prosthesis components-70.4%infection eradication rate;debridement,lavage,change of modular prosthesis components+vacuum-assisted closure-92.8%infection eradication rate;acetabular cup removal+spacer head onto retained stem-89.6%infection eradication rate).With regard to the postoperative antibiotic therapy,no general consensus could be drawn from the available data.Debridement,antibiotic therapy,irrigation,and prosthesis retention is an acceptable solution in the management of early and acute hematogenous periprosthetic hip joint infections.The current literature does not allow for generalization of conclusions with regard to thebest treatment modality.A large,multi-center study is required for identification of the optimal treatment of these infections.

Hip joint center localisation: A biomechanical application to hip arthroplasty population

AIM: To determine hip joint center(HJC) location on hip arthroplasty population comparing predictive and functional approaches with radiographic measurements.METHODS: The distance between the HJC and the mid-pelvis was calculated and compared between the three approaches. The localisation error between the predictive and functional approach was compared using the radiographic measurements as the reference. The operated leg was compared to the non-operated leg.RESULTS: A significant difference was found for the distance between the HJC and the mid-pelvis when comparing the predictive and functional method. The functional method leads to fewer errors. A statistical difference was found for the localization error between the predictive and functional method. The functional method is twice more precise.CONCLUSION: Although being more individualized, the functional method improves HJC localization and should be used in three-dimensional gait analysis.

A Biomimetic Hip Joint Simulator and its Application in in vitro Study of the Integrity of Replacement Cemented Hip

A biomimetic hip joint simulator that can be used to evaluate the outcome of the cemented total hip replacement has been designed, manufactured and evaluated. The simulator produces motion in the extension/flexion plane, with a socket to rotate internal/externally. At the same time a dynamic loading cycle is applied. A validation test was performed on a cemented femoral stem within a novel composite femur. The hone quality has a strong effect on the stem migration and on the integrity of the interfaces. The migration of the stem is a combination of 3-D translation and rotation of the stem. Under the same loading conditions, weak bone allows more stem migration than strong bone. There is a great decrease in the strength of the stem-cement interface after the dynamic test, and the weak bone composite exhibited a greater reduction in interfacial strength than the strong bone composite. The decrease of the interfacial strength indicates that the primary bonding between the stem and the cement mantle had deteriorated and the integrity of stem-cement interface was damaged. The study demonstrates the value of using a hip joint simulator to investigate stem migration and interface integrity within the cemented hip replacement, suggesting that method can be used for in vitro evaluation of the biomaterials used in the cemented hip replacements.

Developing an enhanced recovery after surgery program for oncology patients who undergo hip or knee reconstruction surgery

Enhanced recovery after surgery(ERAS)protocols are applied in orthopedic surgery and are intended to reduce perioperative stress by implementing combined evidence-based practices with the cooperation of various health professionals as an interdisciplinary team.ERAS pathways include pre-operative patient counselling,regional anesthesia and analgesia techniques,post-operative pain management,early mobilization and early feeding.Studies have shown improvement in the recovery of patients who followed an ERAS program after hip or knee arthroplasty,compared with those who followed a traditional care approach.ERAS protocols reduce post-operative stress,contribute to rapid recovery,shorten length of stay(LOS)without increasing the complications or readmissions,improve patient satisfaction and decrease the hospital costs.We suggest that the ERAS pathway could reduce the LOS in hospital for patients undergoing total hip replacement or total knee replacement.These programs require good organization and handling by the multidisciplinary team.ERAS programs increase patient's satisfaction due to their active participation which they experience as personalized treatment.The aim of the study was to develop an ERAS protocol for oncology patients who undergo bone reconstruction surgeries using massive endoprosthesis,with a view to improving the surgical outcomes.

Association between anesthesia technique and complications after hip surgery in the elderly population

BACKGROUND Spinal anesthesia is superior to general anesthesia for postoperative recovery in older patients(≥65 age).However,evidence for this is lacking.AIM To evaluate the effect of anesthesia on postoperative complications in older patients undergoing hip surgery.METHODS This is a retrospective,propensity score-matched,cohort study.Patients≥65-years-old who underwent hip surgery at the Traditional Chinese Medicine of Guangdong Provincial Hospital in China from October 2016 to June 2020 were included.The operative methods were femoral fracture’s internal fixation and hip replacement.The orthopedic doctors in different hospitals of our group have varied requirements for patients’out-of-bed time after surgery.Therefore,spinal anesthesia or general anesthesia was selected according to the requirements of the orthopedic doctors.The primary outcome of this study was complications during the hospitalization of the postoperative patient.The length of hospital stay,postoperative blood transfusion,routine blood analysis,renal function,coagulation function,and inflammatory correlations were secondary outcomes.Propensity score matching(PSM)was performed utilizing logistic regression.RESULTS Among the 864 patients identified from the electronic medical record data database,we screened out those with incomplete medical record data.After PSM of the baseline values of the two groups of patients,data of 309 patients(206 patients in spinal anesthesia group and 103 patients in general anesthesia)were utilized in this study.67/309 patients had complications,including postoperative limb dysfunction,pulmonary infection,delirium,lower extremity venous thrombosis,and shock.The incidence of complications was not related to anesthesia methods(P>0.05),but the levels of D-Dimer(P=0.017),fibrinogen(P=0.005),and high-sensitivity C-reactive protein(hs CRP)(P=0.002)in the spinal anesthesia group were significantly higher than those in the general anesthesia group.CONCLUSION Anesthesia technology is not a risk factor for postoperative complications of hip surgery.The levels of D-Dimer and hs CRP were higher in the spinal anesthesia group.

Dynamic knee valgus kinematics and their relationship to pain in women with patellofemoral pain compared to women with chronic hip joint pain

Background:Dynamic knee valgus(DKV)is an abnormal movement pattern visually characterized by excessive medial movement of the lower extremity during weight bearing.Differences in hip and knee kinematic components of DKV may explain the emergence of different pain problems in people who exhibit the same observed movement impairment.Using a secondary analysis of exiting data sets,we sought to determine whether hip and knee frontal and transverse plane angles during a functional task differed between women with patellofemoral pain and women with chronic hip joint pain and the relationship between joint-specific kinematics and pain in these 2 pain populations.Methods:In the original studies,3-dimensional hip and knee kinematics during a single-limb squat were obtained in 20 women with patellofemoral pain and 14 women with chronic hip joint pain who demonstrated visually classified DKV.Pain intensity during the squat was assessed in both groups.For the secondary analysis,kinematic data were compared between pain groups using their respective control groups as a reference.Within each pain group,correlation coefficients were used to determine the relationship between kinematics and pain during the squat.Results:Hip adduction and contralateral pelvic drop were greater in those with chronic hip joint pain compared to those with patellofemoral pain(effect sizes ≥0.40).Greater knee external rotation(r= 0.47,p= 0.04)was correlated with greater knee pain in those with patellofemoral pain,while greater hip adduction(r = 0.53,p = 0.05)and greater hip internal rotation(r = 0.55,p = 0.04)were correlated with greater hip pain in those with chronic hip joint pain.Conclusion:Hip frontal plane motion was greater in those with chronic hip joint pain compared to those with patellofemoral pain.In both groups,greater abnormal movement at the respective joint(e.g.,knee external rotation in the patellofemoral pain group and hip adduction and internal rotation in the chronic hip joint pain group)was associated with greater pain at that joint during a single-limb squat.

Chromium Content in the Human Hip Joint Tissues

Objective Chromium has many important functions in the human body. For the osseous tissue, its role has not been clearly defined. This study was aimed at determining chromium content in hip joint tissues. Methods A total of 91 hip joint samples were taken in this study, including 66 from females and 25 from males. The sample tissues were separated according to their anatomical parts. The chromium content was determined by the AAS method. The statistical analysis was performed with U Mann-Whitney＇s non-parametric test, P〈0.05. Results The overall chromium content in tissues of the hip joint in the study subjects was as follows： 5.73 μg/g in the articular cartilage, 5.33 μ/g in the cortical bone, 27.86 μ/g in the cancellous bone, 5.95 μg/8 in the fragment of the cancellous bone from the intertrochanteric region, and 2.28 μ/g in the joint capsule. The chromium contents were observed in 2 group patients, it was 7.04 μ/g in people with osteoarthritis and 22.59 μ/g in people with fractures. Conclusion The observed chromium content was highest in the cancellous bone and the lowest in the joint capsule. Chromium content was significantly different between the people with hip joint osteoarthritis and the people with femoral neck fractures.

Jumbo cup in hip joint renovation may cause the center of rotation to increase

BACKGROUND Utilizing the large jumbo cup in revision total hip arthroplasty is an effective approach to cure many lacunar and segmental peripheral bone defects.However,with the use of the jumbo cup,the center of the hip joint may become elevated relative to the primary acetabulum,and the diameter of the large cup is greater.AIM To study the height and the significance of the elevation of the hip joint center.METHODS Eighty-eight patients matched the criteria for this condition and were included in the study.The center height of the hip joint was measured relative to the opposite normal hip joint.The diameter of the jumbo cup was measured and checked according to operation notes,and the diameter of the jumbo cup was measured with a prosthesis label.Then,the horizontal and vertical centers of rotation were measured on the surgical side and opposite side.The average center height of the hip joint on the renovated side and the opposite side and the position of the hip cup relative to the teardrop were compared using a paired t-test.RESULTS Radiometric analysis showed that the average hip joint center was elevated by 7.6 mm.The rotational center height delta of the renovated hip was 7.6±5.6 mm,and there was an obvious difference between the two groups(P=0.00).The difference in horizontal distance was 0.5±5.1 mm(-11.5-14.0 mm),and there was no obvious difference between the two groups(P=0.38).According to the foreign standard,the rotational center height delta of the renovated hip was 7.5±6.2 mm,and there was a significant difference between the two groups(P=0.00).There was no obvious difference between the domestic and foreign standards(P>0.05)between the two groups.CONCLUSION The application of the jumbo cup elevates the rotational center of the hip joint,but it is feasible and effective to use the jumbo cup.

Two-stage revision arthroplasty for coagulase-negative staphylococcal periprosthetic joint infection of the hip and knee

BACKGROUND Periprosthetic joint infections(PJIs)are frequently caused by coagulase-negative Staphylococci(CoNS),which is known to be a hard-to-treat microorganism.Antibiotic resistance among causative pathogens of PJI is increasing.Two-stage revision is the favoured treatment for chronic CoNS infection of a hip or knee prosthesis.We hypothesised that the infection eradication rate of our treatment protocol for two-stage revision surgery for CoNS PJI of the hip and knee would be comparable to eradication rates described in the literature.AIM To evaluate the infection eradication rate of two-stage revision arthroplasty for PJI caused by CoNS.METHODS All patients treated with two-stage revision of a hip or knee prosthesis were retrospectively included.Patients with CoNS infection were included in the study,including polymicrobial cases.Primary outcome was infection eradication at final follow-up.RESULTS Forty-four patients were included in the study.Twenty-nine patients were treated for PJI of the hip and fifteen for PJI of the knee.At final follow-up after a mean of 37 mo,recurrent or persistent infection was present in eleven patients.CONCLUSION PJI with CoNS can be a difficult to treat infection due to increasing antibiotic resistance.Infection eradication rate of 70%-80%may be achieved.

Neuropathic pain-like symptoms and pre-surgery radiographic severity contribute to patient satisfaction 4.8 years post-total joint replacement

AIM To investigate a comprehensive range of factors that contribute to long-term patient satisfaction post-total joint replacement(TJR) in people who had undergone knee or hip replacement for osteoarthritis.METHODS Participants(n = 1151) were recruited from Nottinghamshire post-total hip or knee replacement. Questionnaire assessment included medication use, the pain-DETECT questionnaire(PDQ) to assess neuropathic pain-like symptoms(NP) and TJR satisfaction measured on average 4.8 years post-TJR. Individual factors were tested for an association with post-TJR satisfaction, before incorporating all factors into a full model. Data reduction was carried out using LASSO and receiveroperator characteristic(ROC) curve analysis was used to quantify the contribution of variables to post-TJR satisfaction.RESULTS After data reduction, the best fitting model for post-TJR satisfaction included various measures of pain, history of revision surgery, smoking, pre-surgical X-ray severity, WOMAC function scores and various comorbidities. ROC analysis of this model gave AUC = 0.83(95%CI: 0.80-0.85). PDQ scores were found to capture much of the variation in post-TJR satisfaction outcomes: AUC = 0.79(0.75-0.82). Pre-surgical radiographic severity was associated with higher post-TJR satisfaction: OR_(satisfied) = 2.06(95%CI: 1.15-3.69), P = 0.015.CONCLUSION These results highlight the importance of pre-surgical radiographic severity, post-TJR function, analgesic medication use and NP in terms of post-TJR satisfaction. The PDQ appears to be a useful tool in capturing factors that contribute to post-TJR satisfaction.

Risk of methicillin-resistant staphylococcus aureus prosthetic joint infection in elective total hip and knee arthroplasty following eradication therapy

BACKGROUND Prosthetic joint infection(PJI)is a devastating complication requiring prolonged treatment and multiple operations,leading to significant morbidity for the patient.Patients are routinely tested for methicillin-resistant staphylococcus aureus(MRSA)colonisation.MRSA positive patients are given eradication therapy.We hypothesise that patients who are MRSA positive pre-operatively,have increased risk of developing PJI.AIM To identify deep wound infection(PJI)rates in patients who are colonised MRSA positive compared with those who are not colonised;and long term clinical and radiological outcomes.METHODS All patients who underwent total hip and knee replacements(THR/TKR)between December 2009 and December 2019 were identified.Patients who were also identified as being MRSA positive at pre-operative assessment were then selected.Confirmation of prescribing eradication treatment was recorded.Patient records,including consultation letters,operation notes and microbiology results were reviewed retrospectively.Comparison of outcomes for each MRSA positive patient was made with 2 MRSA negative patients undergoing the same operation of a similar age by the same consultant.RESULTS Screening identified 42 knee and 32 hip arthroplasty patients as MRSA positive,84 MRSA negative knee and 64 hip patients were reviewed.Patients were matched with medical co-morbidities in each group.Mean follow up was 5 years.PJI was identified in 4/32(12.5%)of THR MRSA positive and 3/42(7%)of TKR patients.All patients had PJI within one year of surgery.CONCLUSION MRSA positive patients are given eradication therapy routinely.However,no confirmation of eradication is sought.Patients who have MRSA colonisation preoperatively,in our study had a significantly increased risk of PJI,when compared to negative patients.We would recommend establishing true eradication after treatment prior to arthroplasty.

Use of Dental Inlay for Treatment of Hip Joint Dysregulation: A Case Report

The purpose of this study was to demonstrate the improvement of hip joint dysregulation, including pain (coxalgia), tension, and restriction of joint mobility, using a dental gold alloy inlay. The subject was a 63-year-old man who was suffering from the abovementioned symptoms for several months. On placement of the gold alloy inlay on his chest, the joint flexibility was observed to increase, and the severity of the abovementioned symptoms decreased. When the inlay was placed in his tooth, the flexibility of the joint further increased, and all other symptoms disappeared. No side effects were observed, and the prognosis was good. We believe that these effects may be explained using the electromagnetic waves emitted by the inlay and by the restoration of biting conditions. Future multidisciplinary research focusing on possible underlying mechanisms regarding the relation between electromagnetic waves and dentistry is necessary.

Hip Joint Osteoarthritis Pain Sources and Control

Hip joint osteoarthritis, a widespread disabling disease with no known cause, produces considerable bouts of intractable pain as a result of multiple disease associated problems. This paper examines some sources of osteoarthritic hip joint pain, a poorly understood topic at best. Presented in three parts are data retrieved from several sources, including animal models. It is concluded that to improve the effectiveness of treatments designed to minimize hip osteoarthritis pain, a better understanding of the diverse origins of hip joint pain, and hip joint neurology, may permit the development of more precise as well as targeted pain strategies.

Enhanced recovery after surgery pathway: The use of fascia iliaca blocks causes delayed ambulation after total hip arthroplasty

BACKGROUND Fascia iliaca compartment blocks(FIBs) have been used to provide postoperative analgesia after total hip arthroplasty(THA). However, evidence of their efficacy remains limited. While pain control appears to be satisfactory, quadriceps weakness may be an untoward consequence of the block. Prior studies have shown femoral nerve blocks and fascia iliaca blocks as being superior for pain control and ambulation following THA when compared to standard therapy of parenteral pain control. However, most studies allowed patients to ambulate on post-operative day(POD) 2-3, whereas new guidelines suggest ambulation on POD 0 is beneficial.AIM To determine the effect of FIB after THA in patients participating in an enhanced recovery after surgery(ERAS) program.METHODS We conducted a retrospective analysis of patients undergoing THA with or without FICBs and their ability to ambulate on POD 0 in accordance with ERAS protocol. Perioperative data was collected on 39 patients who underwent THA.Demographic data, anesthesia data, and ambulatory outcomes were compared.RESULTS Twenty patients had FIBs placed at the conclusion of the procedure, while 19 did not receive a block. Of the 20 patients with FIB, only 1 patient was able to ambulate. Of the 19 patients without FIB blocks, 17 were able to ambulate. All patients worked with physical therapy 2 h after arriving in the post-anesthesia care unit on POD 0.CONCLUSION Our data suggests an association between FIB and delayed ambulation in the immediate post-operative period.

Safety and outcomes of hip and knee replacement surgery in liver transplant recipients

BACKGROUND Liver transplant(LT)is becoming increasingly common with improved life expectancy.Joint replacement is usually a safe procedure;however,its safety in LT recipients remains understudied.AIM To evaluate the mortality,outcome,and 90-d readmission rate in LT patients undergoing hip and knee replacement surgery.METHODS Patients with history of LT who underwent hip and knee replacement surgery between 2016 and 2019 were identified using the National Readmission Database.RESULTS A total of 5046119 hip and knee replacement surgeries were identified.3219 patients had prior LT.Mean age of patients with no history of LT was 67.51[95%confidence interval(CI):67.44-67.58],while it was 64.05(95%CI:63.55-64.54)in patients with LT.Patients with history of LT were more likely to have prolonged length of hospital stay(17.1%vs 8.4%,P<0.001).The mortality rate for patients with no history of LT was 0.22%,while it was 0.24%for patients with LT(P=0.792).Patients with history of LT were more likely to have re-admissions within 90 d of initial hospitalization:11.4%as compared to 6.2%in patients without history of LT(P<0.001).The mortality rate between both groups during readmission was not statistically different(1.9%vs 2%,P=0.871)respectively.CONCLUSION Hip and knee replacements in patients with history of LT are not associated with increased mortality;increased readmissions were more frequent in this cohort of patients.Chronic kidney disease and congestive heart failure appear to predict higher risk of readmission.