Purpose. Exeter stem was introduced to Japanese market at 1996. Since then, owing to its excellent clinical results, the number of the stem used has been increased year by year and more than 2000 stems have been implanted during the year 2009. The present study aims to prove its efficacy for Japanese patients by evaluating short term results of four major dedicated hip centers. Method. We present the short-term multi-center results of primary THA with Exeter stem combined with modern cementing technique in 881 patients (1000 hips). The average age of the patients at operation was 62.3years (ranging 23 to 89 years). Mean postoperative follow up period was 4.0 (ranging 2 to 9) years. Results. Intraoperative complications such as femoral fracture were observed in 6 hips. Postoperative cementing grade using Barrack's classification was judged as A for 735 hips, as B for 246 hips, and as C for 4 hips, respectively. Twenty-four patients died with unrelated disease and 52 patients were lost during follow-up period. Follow-up ratio was 94.8%. Thirty postoperative complications which include 9 infections, 14 dislocations, 5 deep vein thrombosis, and 2 sciatic nerve palsies were observed. Symptomatic pulmonary embolization or femoral fracture was not observed. Re-operations for infection and dislocation were performed for 8 and 6 hips, respectively. At the final follow-up, no radiolucent line at bone-cement interface was observed. Cortical hypertrophy was observed in 9.6% at Gruen zone 2 to 6. Kaplan-Meier survivorship analysis predicted a rate of survival at 5 years of 100% with radiolucent line at bone-cement interface of the femur as the endpoint, and of 98.8% when re-operation for any reason was used. Conclusion. The present study revealed excellent short-term result was obtained using Exeter stem combined with modern cementing technique for primary THAs in Japan

Introduction

The results of cementless total hip arthroplasty (THA) vary with data from the UK national Joint Registry being less favourable than that from the Australian registry. The senior author started using a fully cementless THA in 2005 and we aimed to gauge the performance of the implants based on their revision data.

Tracked B-mode ultrasound (US) potentially provides a non-invasive and radiation-free alternative to percutaneous pointer digitization for intra-operative determination of the anterior pelvis plane (APP). However, most of the published approaches demand a direct access to the corresponding landmarks, which can only be presumed for surgical approaches with the patient in supine position. In order to avoid any change of the clinical routine for total hip arthroplasties (THAs), we propose a new method to determine the pelvic orientation, which could be performed in lateral position.

Our proposed method is based on the acquisition of ultrasound images of the ipsilateral hemi-pelvis, namely the posterior superior iliac spines (PSISs) and iliac crest region. The US images are tracked by a navigation system and further processed to extract three-dimensional point clouds. As only one side of the pelvis is accessible, we estimate the symmetry plane (midsagittal plane) of the pelvis based on additionally digitized bilateral anterior superior iliac spine (ASIS) landmarks. This symmetry plane is further used to mirror the ipsilateral US-derived points to the contralateral side of the pelvis and to register and instantiate a pelvic SSM constructed from 30 CT-scans.

The proposed registration method was evaluated using two plastic pelvis models and two cadaveric pelvises together with special custom-made silicone phantoms to simulate the missing soft-tissue. In each trial, the required data were collected with the pelvis rigidly fixed in lateral decubitus position together with ground truth APP landmarks. A registration error of 3.48° ± 1.10° was found for the anteversion angle, while the inclination angle could be reconstructed with a mean error of 1.26° ± 1.62°.

The performed in-vitro experiments showed reasonably good results, taking the sparsity of the input point clouds into consideration.

Purpose: Metal-on-metal articulations are an increasingly popular choice as an alternate bearing surface in total hip arthroplasty (THA) and Resurfacing implants. One advantage of a metal-on-metal bearing is the use of larger diameter femoral heads with hip simulator data demonstrating reduced wear. We performed a prospective, multicentre, randomized, blinded clinical trial comparing 28mm to 36mm metal-on-metal bearings assessing multiple validated outcome measures and serum, erythrocyte and urine metal ions.

Method: Ninety-one patients were randomized to receive a metal-on-polyethylene (34), a 28mm metal-on-metal (25) or a 36mm metal-on-metal (32) insert. All patients received the same acetabular and femoral component. Patients were evaluated pre-operatively, at 6, 12 months and annually thereafter, including an evaluation of serum, erythrocyte and urine cobalt, chromium, and titanium, outcome measures (WOMAC, SF-12, Harris Hip Score) and radiographs.

Results: At a minimum two years follow-up there were no differences in WOMAC, SF-12, Harris Hip scores or radiographs. Patients receiving metal liners had significantly (p< 0.001) elevated metal ion measurements compared with the polyethylene control group, however there were no differences between the 28mm and 36mm metal-on-metal bearings (Median serum Co (mg/L): 0.14(poly), 0.77(28mm), 0.73(36mm). Median erythrocyte Co (mg/L): 0.11(poly), 0.42(28mm), 0.42(36mm). Median urine Co(mg/day): 0.44(poly), 4.55(28mm), 5.42(36mm)). (Median serum Cr(mg/L): 0.17(poly), 1.29(28mm), 0.91(36mm). Median erythrocyte Cr(mg/ L): 1.10(poly), 1.10(28mm), 1.20(36mm). Median urine Cr(mg/day): 0.27(poly), 1.92(28mm), 2.02(36mm)).

Conclusion: Both cobalt and chromium ion measurements were significantly elevated in the blood and urine of the patients randomized to receive the metal-on-metal bearings at all time intervals. There were no differences seen between the 28mm and 36mm metal-on-metal bearings, keeping all other variables identical. The larger diameter bearing therefore provides the potential clinical advantages of improved range of motion and stability, while providing a similar metal ion profile. While reduced wear is seen with larger diameter metal-on-metal bearings in-vitro, we could not demonstrate a reduction in blood or urine metal ion levels in-vivo.

We performed a prospective, randomised, blinded clinical trial comparing metal versus polyethylene bearing surfaces in patients receiving a THA.

Forty-one patients were randomised to receive a metal (twenty-three) or a polyethylene (eighteen) insert with identical femoral and acetabular components. The metal bearing was a 28mm low carbon on high carbon couple. Patients were evaluated pre-operatively, at three, six, twelve months and annually thereafter, including an evaluation of erythrocyte and urine cobalt, chromium, and titanium, outcome measures (WOMAC, SF-12, Harris Hip Score) and radiographs.

No patients were lost to follow-up. At an average 7.2 (range 6.1 – 7.8) years follow-up there were no differences in any outcome measures or radiographic findings. Patients receiving metal liners had significantly elevated metal ion measurements. At most recent follow-up, compared to the polyethylene control group, patients receiving a metal on metal bearing had erythrocyte cobalt levels were eleven times elevated (median 1.4 μg/L (metal) vs 0.12 μg/L (poly), p< .001). Urine cobalt levels were thirty-nine times elevated (median 11.4 μg/L/day (metal) vs 0.29 μg/day (poly), p< .001) and urine chromium levels were twenty-eight times elevated (median 4.75 μg/day (metal) vs 0.17 μg/day (poly), p< .001). Additionally the metal ion levels reached an early steady state level and did not decrease over time. (Erythrocyte Co (μg/L): 1.29 (6 mos), 1.20 (1 yr), 1.0 (2 yr), 1.10 (3 yr), 1.35 (4 yr), 1.40 (5 yr)).

Both cobalt and chromium ion measurements were significantly elevated in the blood and urine of the patients randomised to receive the metal on metal THA at all time intervals. Contrary to previous reports, in 34% of patients with a metal liner, metal ion (erythrocyte cobalt) elevation was still increasing at latest follow-up, and in the overall metal on metal patient cohort, metal ion median levels were not decreasing over time. As in polyethylene wear data, metal ion results are not necessarily generalizable, but are bearing design specific.

Aims. Implant waste during total hip arthroplasty (THA) represents a significant cost to the USA healthcare system. While studies have explored methods to improve THA cost-effectiveness, the literature comparing the proportions of implant waste by intraoperative technology used during THA is limited. The aims of this study were to: 1) examine whether the use of enabling technologies during THA results in a smaller proportion of wasted implants compared to navigation-guided and conventional manual THA; 2) determine the proportion of wasted implants by implant type; and 3) examine the effects of surgeon experience on rates of implant waste by technology used. Methods. We identified 104,420 implants either implanted or wasted during 18,329 primary THAs performed on 16,724 patients between January 2018 and June 2022 at our institution. THAs were separated by technology used: robotic-assisted (n = 4,171), imageless navigation (n = 6,887), and manual (n = 7,721). The primary outcome of interest was the rate of implant waste during primary THA. Results. Robotic-assisted THA resulted in a lower proportion (1.5%) of implant waste compared to navigation-guided THA (2.0%) and manual THA (1.9%) (all p < 0.001). Both navigated and manual THA were more likely to waste acetabular shells (odds ratio (OR) 4.5 vs 3.1) and polyethylene liners (OR 2.2 vs 2.0) compared to robotic-assisted THA after adjusting for demographic and perioperative factors, such as surgeon experience (p < 0.001). While implant waste decreased with increasing experience for procedures performed manually (p < 0.001) or with navigation (p < 0.001), waste rates for robotic-assisted THA did not differ based on surgical experience. Conclusion. Robotic-assisted THAs wasted a smaller proportion of acetabular shells and polyethylene liners than navigation-guided and manual THAs. Individual implant waste rates vary depending on the type of technology used intraoperatively. Future studies on implant waste during THA should examine reasons for non-implantation in order to better understand and develop methods for cost-saving. Cite this article: Bone Jt Open 2024;5(8):715–720

Aims. The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs). Methods. We undertook a registry study combining the National Joint Registry dataset with polyethylene manufacturing characteristics as supplied by the manufacturers. The primary endpoint was revision for any reason. We performed further analyses on other reasons including instability, aseptic loosening, wear, and liner dissociation. The primary analytic approach was Cox proportional hazard regression. Results. A total of 213,146 THAs were included in the analysis. Overall, 2,997 revisions were recorded, 1,569 in THAs with a flat liner and 1,428 in THAs using an asymmetric liner. Flat liner THAs had a higher risk of revision for any reason than asymmetric liner THAs when implanted through a Hardinge/anterolateral approach (hazard ratio (HR) 1.169, 95% confidence interval (CI) 1.022 to 1.337) and through a posterior approach (HR 1.122, 95% CI 1.108 to 1.346). There was no increased risk of revision for aseptic loosening when asymmetric liners were used for any surgical approach. A separate analysis of the three most frequently used crosslinked polyethylene liners was in agreement with this finding. When analyzing THAs with flat liners only, THAs implanted through a Hardinge/anterolateral approach were associated with a reduced risk of revision for instability compared to posterior approach THAs (HR 0.561 (95% CI 0.446 to 0.706)). When analyzing THAs with an asymmetric liner, there was no significant difference in the risk of revision for instability between the two approaches (HR 0.838 (95% CI 0.633 to 1.110)). Conclusion. For THAs implanted through the posterior approach, the use of asymmetric liners reduces the risk of revision for instability and revision for any reason. In THAs implanted through a Hardinge/anterolateral approach, the use of an asymmetric liner was associated with a reduced risk of revision. The effect on revision for instability was less pronounced than in the posterior approach. Cite this article: Bone Joint J 2021;103-B(9):1479–1487

Aims. The aim of this study was to evaluate the survival of a collarless, straight, hydroxyapatite-coated femoral stem in total hip arthroplasty (THA) at a minimum follow-up of 20 years. Methods. We reviewed the results of 165 THAs using the Omnifit HA system in 138 patients, performed between August 1993 and December 1999. The mean age of the patients at the time of surgery was 46 years (20 to 77). Avascular necrosis was the most common indication for THA, followed by ankylosing spondylitis and primary osteoarthritis. The mean follow-up was 22 years (20 to 31). At 20 and 25 years, 113 THAs in 91 patients and 63 THAs in 55 patients were available for review, respectively, while others died or were lost to follow-up. Kaplan-Meier analysis was performed to evaluate the survival of the stem. Radiographs were reviewed regularly, and the stability of the stem was evaluated using the Engh classification. Results. A total of seven stems (4.2%) were revised during the study period: one for aseptic loosening, three for periprosthetic fracture, two for infection, and one for recurrent dislocation. At 20 years, survival with revision of the stem for any indication and for aseptic loosening as the endpoint was 96.0% (95% confidence interval (CI) 92.6 to 99.5) and 98.4% (95% CI 96.2 to 100), respectively. At 25 years, the corresponding rates of survival were 94.5% (95% CI 89.9 to 99.3) and 98.1% (95% CI 95.7 to 99.6), respectively. There was radiological evidence of stable bony fixation in 86 stems (76.1%) and evidence of loosening in four (3.5%) at 20 years. All patients with radiological evidence of loosening were asymptomatic. Conclusion. The Omnifit HA femoral stem offered promising long-term survival into the third decade. Cite this article: Bone Joint J 2024;106-B(3 Supple A):110–114

Aim. Two types of national registers surveil infections after primary total hip arthroplasty (THA) in Norway: The National surveillance system for surgical site infections (NOIS) that surveil all primary THAs 30 days postoperatively for surgical site infections (SSI), and the Norwegian Arthroplasty Register (NAR) that follow all THAs until any surgical reoperation/revision or the death of the patient. Since these registers report on the same THAs we assessed correspondence between and time trends for the two registers in period 2013 to 2022. All reported THAs were included. Method. The THAs were matched on a group level according to sex, age and ASA-class. In addition to descriptive statistics, adjusted Cox regression analyses were performed with adjustment for sex, age group (<45, 45-54, 55-64, 65-74, 75-84, >85 years) and ASA-class (1, 2, 3, 4 and missing). Changes in annual incidence and adjusted hazard rate (aHR) was calculated. Endpoints in the NOIS were 30-Days SSI and 30-Days reoperation for SSI. Endpoints in the NAR were 30-Days and 1-Year reoperation for periprosthetic joint infection (PJI). Results. The NOIS had registered 87,923 THAs with 1,393 (1.58%) SSIs and 765 (0.87%) reoperations for SSI within 30 postoperatively. The NAR had registered 91,194 THAs with 725 (0.80%) reoperations for infection after 30 days, and 1,019 (1.21%) reoperations for infections after one year. The distribution of sex, age and ASA-class was near identical in the two registers. There was a mean annual reduction in risk of both SSI (aHR 0.92 (95% CI 0.90-0.93)) and reoperation for SSI (0.95(0.92-0.97)) and PJI (30-Days: 0.96 (0.94-0.99), 1-Year: 0.95-0.99)) over the period 2013-2022. Conclusions. The NOIS and the NAR have excellent completeness and the registrations in both registers may be considered representative for the Norwegian population. Not all SSI are reoperated. The incidence and risk of SSI (NOIS) and reoperation for PJI (NAR) is declining and may reflect a true reduction in incidence of PJI after primary THA

Short-stem total hip arthroplasty (THA) may have bone sparing properties, which could be advantageous in a younger population with high risk of future revision surgery. We used data from the AOANJRR, LROI and SAR to compare survival rates of primary THA, stems used in the first-time revision procedures as well as the overall survival of first-time revisions between a cohort of short-stem and standard-stem THA. Short-stem THAs (designed as a short stem with mainly metaphyseal fixation) between 2007 and 2021 were identified (n=16,258). A propensity score matched cohort (1:2) with standard THAs in each register was identified (n=32,515). The cohorts were merged into a research dataset. Overall survival at 12 years follow-up was calculated using Kaplan-Meier survival analyses. Stem revisions (short-stem THA n=239, standard-stem THA n=352) were identified. The type of revision stem was classified as standard (<160 mm) or long (>160 mm). The survival rate of all first-time revisions in the two groups was calculated using any type of revision as outcome. The 12 year- overall survival rate (all revisions, all causes) for primary short-stem THAs was 95.3% (CI 94.5–95.9%), which was comparable to 95.2% (CI 94.7–95.7%) for standard-stem THAs. In the short-stem THA group, a standard stem (<160 mm) was more often (59%) used in the first-time revision than in the standard-stem group (47%, p=0.004). The overall survival of the first-time revisions did not differ between cases primarily operated with a short or a standard stem. In our multi-national register study, the overall survival rate of short stems was similar to that of standard stems. In short stem revisions there was a higher likelihood of using a standard-length stem for the revision compared with first-time revisions of standard stems. This finding might indicate bone-sparing properties with short-stemmed THAs

Aims. In 2015, we published the results of our ceramic-on-metal (CoM) total hip arthroplasties (THAs) performed between October 2007 and July 2009 with a mean follow-up of 34 months (23 to 45) and a revision rate of 3.1%. The aim of this paper is to present the longer-term outcomes. Methods. A total of 264 patients were reviewed at a mean of 5.8 years (4.6 to 7.2) and 10.1 years (9.2 to 10.6) to determine revision rate, pain, outcome scores, radiological analysis, and blood ion levels. Those who were unwilling or unable to travel were contacted by telephone. Results. The all-cause revision rate at six years was 3.1% (eight THAs), increasing to 8.8% (18 THAs) at ten years. Of these, there were four and then seven bearing-related revisions at six and ten years, respectively. There was a statistically significant deterioration in the visual analogue scale pain score and Oxford Hip Score (OHS) between six and ten years. There were 18 CoM THAs in 17 patients who had a cobalt or chromium level over 4 ppb and ten CoM THAs in nine patients who had a cobalt or chromium level higher than 7 ppb with a statistically significant increase in chromium levels only between the two timepoints. Overall, 84 stems (39.1%) had significant radiolucent lines at ten years compared to 65 (25.5%) at six years. Conclusion. When compared to the original review, there has been a significant deterioration in pain score, OHS, radiograph appearance, and, most critically, survival has fallen to 91.2%, which does not meet the Orthopaedic Data Evaluation Panel (ODEP) 10 A* 95% threshold. Although this bearing is no longer on the market, 2.5% were bearing-related revisions, which have relevance to the discussion around modular dual-mobility implants that have a similar metal interface

It is anecdotally thought that a good outcome from the first of staged total hip arthroplasties (THAs) is predictive of benefit on the contralateral side. The objective was to determine whether outcome from the first THA could be used to predict outcome from the second, contralateral THA. A retrospective cohort study of consecutive patients undergoing staged THAs at a UK arthroplasty centre over 25-years (1995–2020). A control THA group was identified and matched for age, gender, BMI, implant and diagnosis. One-year patient-reported outcome data was available for 91% 1543/1700. 1700 patients who underwent staged THA were compared to 1700 matched controls. Preoperative status was comparable for pain, function, and modified Harris hip score (mHHS, mean 41 SD 13 for both groups). At one year, there was a 2% dissatisfaction rate in all groups (first of staged THAs, second of staged THAs and controls). Groups were similar in terms of pain, function and mHHS (mean 88 SD 11 for all groups). For every 100 patients undergoing staged THAs, 87 had a bilateral good outcome (mHHS >70 both), 11 had unilateral poor outcome (mHHS >70 one, <70 other) and 2 had bilateral poor outcome (mHHS <70 both). If the first THA had a good outcome, the relative risk of a bad outcome was 20% less than for controls (RR 0.8 95% CI 0.6–1.1). If the first THA had a poor outcome, the risk of a second poor outcome was 4.5 times higher (RR 4.5 95% CI 3.2–6.4), increasing from 6% to 29% (absolute risk). Patients undergoing staged THAs with a good outcome from the first THA were less likely to have a bad outcome with the second. Risk of a poor outcome after a previous successful THA was 6% but rose to almost 30% with a previous poor outcome. This remained after correcting for patient variables including gender, age, BMI and diagnosis, indicating a potentially novel independent risk factor for poor outcome from staged THA

Aim. Antimicrobial resistance (AMR) aggravates an already difficult treatment of periprosthetic joint infections (PJI). The prevalence of drug-resistant pathogens varies across countries and increases over time. Regular monitoring of bacteriological analyses should be performed. Due to many factors influencing the AMR, the correct choice of antimicrobial management remains arguable. The primary purpose of this retrospective study was to identify and compare causative bacteria and to compare the incidence of antibiotic resistance between the septic revision total knee arthroplasty (TKA) and septic revision total hip arthroplasty (THA). Method. A review of all revision TKAs and revision THAs, undertaken between 2007 and 2020 in a tertiary referral centre, was performed. Included were cases meeting the consensus criteria for PJI, in which an organism has been identified. There were no major differences in tissue sampling between revision TKAs and revision THAs over time. Results. A total of 228 bacterial strains, isolated after revision TKA and THA, were analysed for their resistance to 20 different antibiotics. There was a statistically significant higher occurrence of Gram-negative bacteria (p=0.002) and Enterococcus species (p=0.026) identified after revision THAs compared to TKA. The comparison of antibiotic resistance between revision TKAs and revision THAs was statistically significant in 9 of 20 analysed antibiotics. Pathogens isolated after revision THA were much more resistant compared to pathogens isolated after revision TKA. Resistance in revision THAs was significantly higher to oxacillin (p=0.03), ciprofloxacin (p<0.001), levofloxacin (p<0.001), moxifloxacin (p=0.005), clindamycin (p<0.001), co-trimoxazole (p<0.001), imipenem (p=0.01), rifampicin (p=0.005) and tetracycline (p=0.009). There was no significantly higher resistance of pathogens isolated after revision TKAs detected. No statistically significant difference in antibiotic resistance of Gram-negative bacteria between revision TKA and revision THA was observed. Conclusions. The occurrence and the resistance of bacteria to antibiotics differs significantly between revision TKAs and revision THAs. This has implications on of the choice of empirical antibiotic in revision surgery as well as prophylactic antibiotic in primary surgery, depending on the joint that is to be replaced

Aims. A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient’s quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach. Methods. A group of eight patients revised due to a PJI with a previous lateral approach was compared with a group of 21 revised THAs without infection, performed using the same approach. The primary variables of the study were the fibril diameter, as seen in transmission electron microscopy (TEM), and the total degeneration score (TDS), as seen under the light microscope. An analysis of bacteriology, classification of infection, and antibiotic treatment was also performed. Results. Biopsy samples from the GMED from infected patients revealed a larger fibril diameter than control patients, as seen in the TEM (p < 0.001). Uninfected patients were slightly older and had their revisions performed significantly later than the infected patients. Histologically, samples from infected patients revealed significantly more vascularity (p < 0.001), the presence of glycosaminoglycans (p < 0.001), and a higher TDS (p = 0.003) than the control patients. The majority of patients had staphylococcal infections of various species. Conclusion. More histological degeneration in the GMED was found in patients undergoing THA revision surgery due to PJI than in patients undergoing THA revision surgery due to other reasons. Cite this article: Bone Jt Open 2023;4(8):628–635

We have previously reported on the improved all-cause revision and improved revision for instability risk in lipped liner THAs using the NJR dataset. These findings corroborate studies from the Australian (AOANJRR) and New Zealand (NZOA) joint registries. The optimal orientation of the lip in THAs utilising a lipped liner remains unclear to many surgeons. The aim of this study was to identify impingement-free optimal liner orientations whilst considering femoral stem version, cup inclination and cup version. A cementless THA kinematic model was developed using a 20 degree XLPE liner. Physiological ROM and provocative dislocation manoeuvre analyses were performed. A total of 9 cup positions were analysed (inclination 30–40–50 degrees, anteversion 5-15-25 degrees) and combined with 3 stem positions (anteversion 0-15-30 degrees) and 5 lip orientations (right hip 11 to 7 o'clock). Some lip orientation/component position combinations lead to impingement within the physiological ROM range. Using a lipped liner increases the femoral head travel distance prior to dislocation when impingement occurs in the plane of the lip. In THAs with a cup inclination of 30 and 40 degrees, inferior lip orientations (7–8 o'clock for a right hip) performed best. Superior lip orientation performed best with a cup inclination of 50 degrees. Femoral stem version has a significant effect on the range of movement prior to impingement and hence the preferred lip orientation. The optimal orientation of the lip in lipped liner THA is dependent on the position of both the acetabular and femoral components. In the common component orientation combination of stem anteversion 15, cup inclination 40 and cup anteversion 15, the optimal lip orientation was postero-inferiorly (8 o'clock for a right hip). Preventing impingement during physiological ROM is possible with appropriate lip liner orientation

Previous scientific studies have highlighted how coupling is an important element affecting total hip arthroplasty's survival. This study aims to evaluate whether metal-on-metal (MOM) coupling could be a statistically significant risk factor. The data from the regional joint registry (Registro dell'Impiantologia Protesica Ortopedica, RIPO) was used for analysis. The data collection accuracy of this registry was 97.2% in 2017. We retrospective evaluate all MOM total hip arthroplasties (THAs) implanted in our department between January 01st 2000 and December 31st 2011. We used a control group composed by all other prosthesis implanted in our Department in the same time lapse. We registered 660 MOM THAs. Mean age of patients was 66.9 years. 603 patients have a >36mm head, while 78 a <36 mm one. Neck modularity was present in half of patients. 676 implants were cementless. We registered 69 revisions, especially due to aseptic mobilization (16 THAs), implant breakage (9 THAs) and periprosthetic fracture (6 THAs). The MOM THAs overall Kaplan-Meier survival rate was 87.2 at 15 years, and the difference between MOM THAs and other implants two curves is statistically significant (p<0.05). Male sex is a significant risk factors. Further evaluations are in progress to establish the presence of any additional risk factors. We think weight and/or BMI may be included in this category. Our study confirms the data currently present in the literature regarding a lower survival of metal-on-metal hip prostheses. The male sex is a statistically significant risk factor (p<0.05), while age, head size and modularity of the prosthetic neck are not statistically significant (p>0.05). Any new finds will be presented at the congress venue

The interest in day-case hip arthroplasty is increasing; however, there are conflicting results regarding readmission risk, and little is known about patients’ attitude towards day-case surgery. We aimed to investigate differences in 30-day readmission rates between day-case patients and single-overnight-stay patients following total hip arthroplasty (THA) and explore patients’ attitude towards day-case surgery. From the Danish National Patient Register we identified 29,486 THAs (1353 day-case THAs and 28,133 single-overnight-stay THAs) performed between 2010 and 2020. Day-case surgery was defined as discharge on the day-of-surgery. Overnight admissions within 30 days of surgery were considered readmissions. Differences in readmission rates between day-case and single-overnight-stay patients were investigated using logistic regression adjusted for patient characteristics and year of surgery. In a single-center descriptive study, 2395 hip arthroplasty patients from 2016 to start-2023 answered a questionnaire on patient characteristics, attitude towards day-case surgery and patient-reported outcome measures (PROM). The overall 30-day readmission rate was 4.4% (CI: 4.2–4.6%) with no difference between day-case (4.4%) and single-overnight-stay THAs (4.4%) (odds-ratio: 1.2 [CI: 0.91–1.6]). In the descriptive study answers to the question whether patients were interested in being discharged on the day of surgery, were: “Yes” = 41%, “Do not know” = 20%, “No” = 39%. Patients responding “No” had lower preoperative PROM-scores, were older (“No” = 70.2 y vs. “Yes” = 65.3 y), and more often female (“No” = 72% vs. “Yes” = 52% female). Based on nationwide data from 2010–2020, day-case THA patients were not more likely to be readmitted compared to single-overnight-stay patients. However, most patients were not positive towards day-case surgery. While surgeons may consider day-case surgery to be safe, patients are not intuitively positive, indicating an attitude mismatch. To achieve high success rate and patient satisfaction in day-case surgery, shared-decision making initiatives within day-case surgery are needed

Angular proximal femoral deformities increase the technical complexity of primary total hip arthroplasties (THAs). The goals were to determine the long-term implant survivorship, risk factors, complications, and clinical outcomes of contemporary primary THAs in this difficult cohort. Our institutional total joint registry was used to identify 119 primary THAs performed in 109 patients with an angular proximal femoral deformity between 1997 and 2017. The deformity was related to previous femoral osteotomy in 85%, and developmental or metabolic disorders in 15%. 53% had a predominantly varus angular deformity. The mean age was 44 years, mean BMI was 29 kg/m. 2. , and 59% were female. An uncemented metaphyseal fixation stem was used in 30%, an uncemented diaphyseal fixation stem in 28%, an uncemented modular body stem with metaphyseal fixation sleeve in 24%, and a cemented stem in 18%. Simultaneous corrective femoral osteotomy was performed in 18%. Kaplan-Meier survivorships and Harris hip scores were reported. Mean follow-up was 8 years. The 10-year survivorships free of femoral loosening, aseptic femoral revision, any revision, and any reoperation were 95%, 93%, 90% and 88%, respectively. Revisions occurred in 13 hips for: aseptic femoral component loosening (3), stem fracture (2), dislocation (2), aseptic acetabular loosening (2), polyethylene liner exchange (2), and infection (2). Preoperative varus angular deformities were associated with a higher risk of any revision (HR 10, p=0.03), and simultaneous osteotomies with a higher risk of any reoperation (HR 3.6, p=0.02). Mean Harris hip scores improved from 52 preoperatively to 82 at 10 years (p<0.001). In the largest series to date of primary THAs in patients with angular proximal femoral deformities, we found a good 10-year survivorship free from any revision. Varus angular deformities, particularly those treated with a simultaneous osteotomy due to the magnitude or location of the deformity, had a higher reoperation rate. Keywords: Proximal femoral deformity; dysplasia; femoral osteotomy; survivorship; revision. Level of evidence: Level III, comparative retrospective cohort

Total hip arthroplasty (THA) is an effective treatment for symptomatic hip osteoarthritis (OA). Computer-navigation technologies in total knee arthroplasty show evidence-supported survivorship advantages and are used widely. The aim of this study was to determine the revision outcome of hip commercially available navigation technologies. Data from the Australian Orthopaedic Association National Joint Replacement Registry from January 2016 to December 2020 included all primary THA procedures performed for osteoarthritis (OA). Procedures using the Intellijoint HIP® navigation were identified and compared to procedures inserted using ‘other’ computer navigation systems and to all non-navigated procedures. The cumulative percent revision (CPR) was compared between the three groups using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazards models, adjusted for age and gender. A prosthesis specific analysis was also performed. There were 1911 procedures that used the Intellijoint® system, 4081 used ‘other’ computer navigation, and 160,661 were non-navigated. The all-cause 2-year CPR rate for the Intellijoint HIP® system was 1.8% (95% CI 1.2, 2.6), compared to 2.2% (95% CI 1.8, 2.8) for other navigated and 2.2% (95% CI 2.1, 2.3) for non-navigated cases. A prosthesis specific analysis identified the Paragon/Acetabular Shell THAs combined with the Intellijoint HIP® system as having a higher (3.4%) rate of revision than non-navigated THAs (HR = 2.00 (1.01, 4.00), p=0.048). When this outlier combination was excluded, the Intellijoint® system group demonstrated a two-year CPR of 1.3%. There was no statistical difference in the CPR between the three groups before or after excluding Paragon/Acetabular Shell system. The preliminary data presented demonstrate no statistical difference in all cause revision rates when comparing the Intellijoint HIP® THA navigation system with ‘other’ navigation systems and ‘non-navigated’ approaches for primary THAs performed for OA. The current sample size remains too small to permit meaningful subgroup statistical comparisons

Background and purpose. Previous publications have reported an increased but levelling out risk of revision for infection after total hip arthroplasty (THA) in Norway. We assessed the changes in risk of major (cup and/or stem, 1- or 2-stage) and minor revisions (debridement, exchange of modular parts, antibiotics and implant retention (DAIR)) for infection after primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 2005-2022. Patients and methods. Primary THAs reported to the NAR from 2005 to 2022 were included. Time was stratified into time periods (2005-2009, 2010-2018, 2019-2022) based on a previous publication. Cox regression analyses, adjusted for sex, age and ASA-classification, with the first revision for infection were performed. Results. 140,338 primary THAs met the inclusion criteria. 1.3% (1,785) were revised for infection during the study period. 0.5% (638) had major revisions, whereas 0.8% (1,147) had DAIRs for infection. The risk of revision for infection was 1.2 (95%CI 1.1-1.4) for 2010-2018 and 1.0 (0.8-1.1) for 2019-2022 compared to 2005-2009. Compared to 2010-2018, the risk of revision for infection was 0.8 (0.7-0.9) for 2019-2022. The risk of DAIR for infection was 1.5 (1.3-1.9) for 2010-2018 and 1.2 (1.0-1.4) for 2019-2022 compared to 2005-2009. Compared to 2010-2018, the risk of DAIR for infection was 0.8 (0.7-0.9) for 2019-2022. The risk of major revision for infection was 0.8 (0.7-1.0) for 2010-2018 and 0.8 (0.6-1.0) for 2019-2022 compared to 2005-2009. Interpretation. The overall risk of revision for infection after THA, in Norway, has decreased in the period 2019-2022. The risk for DAIR initially increased in the period 2005-2009, levelled out 2010-2018 before starting to decrease in 2019-2022. The risk of major revision for infection was reduced in the period 2005-2009 before levelling out. This shows changes in revision strategies, but may also reflect a true decrease in periprosthetic joint infection