Aims. Waiting times for arthroplasty surgery in Northern Ireland are among the longest in the NHS, which have been further lengthened by the onset of the COVID-19 global pandemic in March 2020. The Department of Health in Northern Ireland has announced a new Elective Care Framework (ECF), with the framework proposing that by March 2026 no patient will wait more than 52 weeks for inpatient/day case treatment. We aimed to assess the feasibility of achieving this with reference to total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods. Mathematical modelling was undertaken to calculate when the ECF targets will be achieved for THA and TKA, as well as the time when waiting lists for THA and TKA will be cleared. The number of patients currently on the waiting list and percentage operating capacity relative to pre-COVID-19 capacity was used to determine future projections. Results. As of May 2021, there were 3,757 patients awaiting primary THA and 4,469 patients awaiting primary TKA in Northern Ireland. Prior to April 2020, there were a mean 2,346 (2,085 to 2,610) patients per annum boarded for primary THA, a mean 2,514 (2,494 to 2,514) patients per annum boarded for primary TKA, and there were a mean 1,554 primary THAs and 1,518 primary TKAs performed per annum. The ECF targets for THA will only be achieved in 2030 if operating capacity is 200% of pre COVID-19 pandemic capacity and in 2042 if capacity is 170%. For TKA, the targets will be met in 2034 if capacity is 200% of pre-COVID-19 pandemic capacity. Conclusion. This modelling demonstrates that, in the absence of major funding and reorganization of elective orthopaedic care, the targets set out in the ECF will not be achieved with regard to THA and TKA. Waiting times for THA and TKA surgery in Northern Ireland are likely to remain greater than 52 weeks for most of this decade. Cite this article: Bone Jt Open 2022;3(4):302–306

Aims. The aims of this study were to determine the clinical and radiographic outcomes, implant survivorship, and complications of patients with a history of poliomyelitis undergoing total hip arthroplasty (THA) in affected limbs and unaffected limbs of this same population. Patients and Methods. A retrospective review identified 51 patients (27 male and 24 female, 59 hips) with a mean age of 66 years (38 to 88) and with the history of poliomyelitis who underwent THA for degenerative arthritis between 1970 and 2012. Immigrant status, clinical outcomes, radiographic results, implant survival, and complications were recorded. Results. In all, 32 THAs (63%) were performed on an affected limb, while 27 (37%) were performed on an unaffected limb. The overall ten-year survivorship free from aseptic loosening, any revision, or any reoperation were 91% (95% CI 0.76 to 0.99), 91% (95% CI 0.64 to 0.97) and 87% (95% CI 0.61 to 0.95), respectively. There were no revisions for prosthetic joint infection. There were no significant differences in any of the above parameters if THA was on the affected or unaffected control limbs. Conclusion. Patients with a history of poliomyelitis who undergo THA on the affected or unaffected limbs have similar results with overall survivorship and complication rates to those reported results in patients undergoing THA for osteoarthritis. At long-term follow-up, previous clinical concerns about increased hip instability due to post-polio abductor weakness were not observed. Cite this article: Bone Joint J 2018;100-B:733–9

There is little evidence on the cost effectiveness of different brands of hip prostheses. We compared lifetime cost effectiveness of frequently used brands within types of prosthesis including cemented (Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed) and hybrid (Exeter V40 Trilogy, Exeter V40 Trident, and CPT Trilogy). We used data from three linked English national databases to estimate the lifetime risk of revision, quality-adjusted life years (QALYs) and cost. . For women with osteoarthritis aged 70 years, the Exeter V40 Elite Plus Ogee had the lowest risk of revision (5.9% revision risk, 9.0 QALYs) and the CPT Trilogy had the highest QALYs (10.9% revision risk, 9.3 QALYs). Compared with the Corail Pinnacle (9.3% revision risk, 9.22 QALYs), the most commonly used brand, and assuming a willingness-to-pay of £20 000 per QALY gain, the CPT Trilogy is most cost effective, with an incremental net monetary benefit of £876. Differences in cost effectiveness between the hybrid CPT Trilogy and Exeter V40 Trident and the cementless Corail Pinnacle and Taperloc Exceed were small, and a cautious interpretation is required, given the limitations of the available information. However, it is unlikely that cemented brands are among the most cost effective. Similar patterns of results were observed for men and other ages. The gain in quality of life after total hip arthroplasty, rather than the risk of revision, was the main driver of cost effectiveness. Cite this article: Bone Joint J 2015;97-B:762–70

Aims. We report on the outcome of the Exeter Contemporary flanged cemented all-polyethylene acetabular component with a mean follow-up of 12 years (10 to 13.9). This study reviewed 203 hips in 194 patients. 129 hips in 122 patients are still in situ; 66 hips in 64 patients were in patients who died before ten years, and eight hips (eight patients) were revised. Clinical outcome scores were available for 108 hips (104 patients) and radiographs for 103 hips (100 patients). Patients and Methods. A retrospective review was undertaken of a consecutive series of 203 routine primary cemented total hip arthroplasties (THA) in 194 patients. Results. There were no acetabular component revisions for aseptic loosening. Acetabular revision was undertaken in eight hips. In four hips revision was necessitated by periprosthetic femoral fractures, in two hips by recurrent dislocation, in one hip for infection and in one hip for unexplained ongoing pain. . Oxford and Harris hip scores demonstrated significant clinical improvement (all p < 0.001). Radiolucent lines were present in 37 (36%) of the 103 acetabular components available for radiological evaluation. In 27 of these, the line was confined to zone 1. No component had migrated. . Conclusion. Kaplan–Meier survivorship, with revision for aseptic loosening as the endpoint, was 100% at 12.5 years and for all causes was 97.8% (95% confidence interval 95.6 to 100) when 40 components remained at risk. The Exeter Contemporary flanged cemented acetabular component demonstrates excellent survivorship at 12.5 years. Take home message: The Exeter Contemporary flanged cemented acetabular component has excellent clinical outcomes and survivorship when used with the Exeter stem in total hip arthroplasty. . Cite this article: Bone Joint J 2016;98-B:307–12

Aims. Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA. Methods. This prospective randomized controlled trial (RCT) included 60 patients with symptomatic hip osteoarthritis undergoing conventional THA (CO THA) versus robotic arm-assisted THA (RO THA). Patients in both arms underwent pre- and postoperative CT scans, and a patient-specific plan was created using the robotic software. The COR, combined offset, acetabular orientation, and leg length discrepancy were measured on the pre- and postoperative CT scanogram at six weeks following surgery. Results. There were no significant differences for any of the baseline characteristics including spinopelvic mobility. The absolute error for achieving the planned horizontal COR was median 1.4 mm (interquartile range (IQR) 0.87 to 3.42) in RO THA versus 4.3 mm (IQR 3 to 6.8; p < 0.001); vertical COR mean 0.91 mm (SD 0.73) in RO THA versus 2.3 mm (SD 1.3; p < 0.001); and combined offset median 2 mm (IQR 0.97 to 5.45) in RO THA versus 3.9 mm (IQR 2 to 7.9; p = 0.019). Improved accuracy was observed with RO THA in achieving the desired acetabular component positioning (root mean square error for anteversion and inclination was 2.6 and 1.3 vs 8.9 and 5.3, repectively) and leg length (mean 0.6 mm vs 1.4 mm; p < 0.001). Patient-reported outcome measures were comparable between the two groups at baseline and one year. Participants in the RO THA group needed fewer physiotherapy sessions postoperatively (median six (IQR 4.5 to 8) vs eight (IQR 6 to 11; p = 0.005). Conclusion. This RCT suggested that robotic-arm assistance in THA was associated with improved accuracy in restoring the native COR, better preservation of the combined offset, leg length correction, and superior accuracy in achieving the desired acetabular component positioning. Further evaluation through long-term and registry data is necessary to assess whether these findings translate into improved implant survival and functional outcomes. Cite this article: Bone Joint J 2024;106-B(4):324–335

Aims

The aim of this study was to investigate whether the use of antibiotic-loaded bone cement influenced the risk of revision surgery after primary total hip arthroplasty (THA) for osteoarthritis.

Aims

Dual mobility (DM) bearings are an attractive treatment option to obtain hip stability during challenging primary and revision total hip arthroplasty (THA) cases. The purpose of this study was to analyze data submitted to the American Joint Replacement Registry (AJRR) to characterize utilization trends of DM bearings in the USA.

Aims. The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system. Methods. This study included 30 CO THAs versus 30 RO THAs performed by a single surgeon. Intraoperative photographs of the osseous acetabulum and periacetabular soft-tissues were obtained prior to implantation of the acetabular component, which were used to develop the proposed classification system. Interobserver and intraobserver variabilities of the proposed classification system were assessed. Results. The BOne trauma and Soft-Tissue Injury classification system in total Hip arthroplasty (BOSTI Hip) grades osseous acetabular trauma and periarticular muscle damage during THA. The classification system has an interclass correlation coefficient of 0.90 (95% CI 0.86 to 0.93) for interobserver agreement and 0.89 (95% CI 0.84 to 0.93) for intraobserver agreement. RO THA was associated with improved BOSTI Hip scores (p = 0.002) and more pristine osseous surfaces in the anterior superior (p = 0.001) and posterior superior (p < 0.001) acetabular quadrants compared with CO THA. There were no differences between the groups in relation to injury to the gluteus medius (p = 0.084), obturator internus (p = 0.241), piriformis (p = 0.081), superior gamellus (p = 0.116), inferior gamellus (p = 0.132), quadratus femoris (p = 0.208), and vastus lateralis (p = 0.135), but overall combined muscle injury was reduced in RO THA compared with CO THA (p = 0.023). Discussion. The proposed BOSTI Hip classification provides a reproducible grading system for stratifying iatrogenic bone trauma and soft-tissue injury during THA. RO THA was associated with improved BOSTI Hip scores, more pristine osseous acetabular surfaces, and reduced combined periarticular muscle injury compared with CO THA. Further research is required to understand if these intraoperative findings translate to differences in clinical outcomes between the treatment groups. Cite this article: Bone Joint J 2024;106-B(9):898–906

Aims. Iliopsoas impingement occurs in 4% to 30% of patients after undergoing total hip arthroplasty (THA). Despite a relatively high incidence, there are few attempts at modelling impingement between the iliopsoas and acetabular component, and no attempts at modelling this in a representative cohort of subjects. The purpose of this study was to develop a novel computational model for quantifying the impingement between the iliopsoas and acetabular component and validate its utility in a case-controlled investigation. Methods. This was a retrospective cohort study of patients who underwent THA surgery that included 23 symptomatic patients diagnosed with iliopsoas tendonitis, and 23 patients not diagnosed with iliopsoas tendonitis. All patients received postoperative CT imaging, postoperative standing radiography, and had minimum six months’ follow-up. 3D models of each patient’s prosthetic and bony anatomy were generated, landmarked, and simulated in a novel iliopsoas impingement detection model in supine and standing pelvic positions. Logistic regression models were implemented to determine if the probability of pain could be significantly predicted. Receiver operating characteristic curves were generated to determine the model’s sensitivity, specificity, and area under the curve (AUC). Results. Highly significant differences between the symptomatic and asymptomatic cohorts were observed for iliopsoas impingement. Logistic regression models determined that the impingement values significantly predicted the probability of groin pain. The simulation had a sensitivity of 74%, specificity of 100%, and an AUC of 0.86. Conclusion. We developed a computational model that can quantify iliopsoas impingement and verified its accuracy in a case-controlled investigation. This tool has the potential to be used preoperatively, to guide decisions about optimal cup placement, and postoperatively, to assist in the diagnosis of iliopsoas tendonitis. Cite this article: Bone Jt Open 2023;4(1):3–12

Aims. Conventional patient-reported surveys, used for patients undergoing total hip arthroplasty (THA), are limited by subjectivity and recall bias. Objective functional evaluation, such as gait analysis, to delineate a patient’s functional capacity and customize surgical interventions, may address these shortcomings. This systematic review endeavours to investigate the application of objective functional assessments in appraising individuals undergoing THA. Methods. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied. Eligible studies of THA patients that conducted at least one type of objective functional assessment both pre- and postoperatively were identified through Embase, Medline/PubMed, and Cochrane Central database-searching from inception to 15 September 2023. The assessments included were subgrouped for analysis: gait analysis, motion analysis, wearables, and strength tests. Results. A total of 130 studies using 15 distinct objective functional assessment methods (FAMs) were identified. The most frequently used method was instrumented gait/motion analysis, followed by the Timed-Up-and-Go test (TUG), 6 minute walk test, timed stair climbing test, and various strength tests. These assessments were characterized by their diagnostic precision and applicability to daily activities. Wearables were frequently used, offering cost-effectiveness and remote monitoring benefits. However, their accuracy and potential discomfort for patients must be considered. Conclusion. The integration of objective functional assessments in THA presents promise as a progress-tracking modality for improving patient outcomes. Gait analysis and the TUG, along with advancing wearable sensor technology, have the potential to enhance patient care, surgical planning, and rehabilitation. Cite this article: Bone Joint J 2024;106-B(8):764–774

Aims. Total hip arthroplasty (THA) is a common procedure to address pain and enhance function in hip disorders such as osteoarthritis. Despite its success, postoperative patient recovery exhibits considerable heterogeneity. This study aimed to investigate whether patients follow distinct pain trajectories following THA and identify the patient characteristics linked to suboptimal trajectories. Methods. This retrospective cohort study analyzed THA patients at a large academic centre (NYU Langone Orthopedic Hospital, New York, USA) from January 2018 to January 2023, who completed the Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity questionnaires, collected preoperatively at one-, three-, six-, 12-, and 24-month follow-up times. Growth mixture modelling (GMM) was used to model the trajectories. Optimal model fit was determined by Bayesian information criterion (BIC), Vuong-Lo-Mendell-Rubin likelihood ratio test (VLMR-LRT), posterior probabilities, and entropy values. Association between trajectory groups and patient characteristics were measured by multinomial logistic regression using the three-step approach. Results. Among the 1,249 patients, a piecewise GMM model revealed three distinct pain trajectory groups: 56 patients (4.5%) in group 1; 1,144 patients (91.6%) in group 2; and 49 patients (3.9%) in group 3. Patients in group 2 experienced swift recovery post-THA and minimal preoperative pain. In contrast, groups 1 and 3 initiated with pronounced preoperative pain; however, only group 3 exhibited persistent long-term pain. Multinomial regression indicated African Americans were exceedingly likely to follow trajectory groups 1 (odds ratio (OR) 2.73) and 3 (OR 3.18). Additionally, odds of membership to group 3 increased by 12% for each BMI unit rise, by 19% for each added postoperative day, and by over four if discharged to rehabilitation services (OR 4.07). Conclusion. This study identified three distinct pain trajectories following THA, highlighting the role of individual patient factors in postoperative recovery. This emphasizes the importance of preoperatively addressing modifiable risk factors associated with suboptimal pain trajectories, particularly in at-risk patients. Cite this article: Bone Jt Open 2024;5(3):174–183

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

Aims. This study aimed to describe practice variation in the use of total hip arthroplasty (THA) for older patients with femoral neck fracture and to determine the association between patient, surgeon, and institution factors and treatment with THA. Methods. We performed a cross-sectional analysis of 49,597 patients aged 60 years and older from Ontario, Canada, who underwent hemiarthroplasty or THA for femoral neck fracture between 2002 and 2017. This population-based study used routinely collected healthcare databases linked through ICES (formerly known as the Institute for Clinical Evaluative Sciences). Multilevel logistic regression modelling was used to quantify the association between patient, surgeon, and institution-level variables and whether patients were treated with THA. Variance partition coefficient and median odds ratios were used to estimate the variation attributable to higher-level variables and the magnitude of effect of higher-level variables, respectively. Results. Over the study period, 9.4% of patients (n = 4,638) were treated with THA. Patient factors associated with higher likelihood of treatment by THA included: younger age, male sex, and diagnosis with rheumatoid arthritis. Long-term care residence, use of home care services prior to hip fracture, diagnosis of dementia, higher comorbidity burden, and the most marginalized group were negatively associated with treatment by THA. Treating surgeon and institution accounted for 54.2% and 17.8% of the total variation in treatment with THA, respectively. Surgeon volume of THA procedures in the 365 days prior to surgery was the strongest higher-level predictor of treatment with THA. Specific treating surgeons and institutions still accounted for significant proportions of the variability in treatment with THA (40.3% and 19.5% of total observed variation, respectively) after controlling for available patient, surgeon, and institution-level variables. Conclusion. The strongest predictors for treatment of patients with femoral neck fracture with THA were patient age, treating surgeon, and treating institution. This practice variation highlights differential access to care for patients. Cite this article: Bone Joint J 2023;105-B(2):180–189

Aims. Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies. Methods. Posterior approach THAs were carried out on three cadavers by an expert orthopaedic surgeon. An instrumented mallet and introducer were used to insert cementless acetabular cups. The motion of the mallet, relative to the introducer, was analyzed for a total of 110 strikes split into low-, medium-, and high-effort strikes. Three parameters were extracted from these data: strike vector, strike offset, and mallet face alignment. Results. The force vector of the mallet strike, relative to the introducer axis, was misaligned by an average of 18.1°, resulting in an average wasted strike energy of 6.1%. Furthermore, the mean strike offset was 19.8 mm from the centre of the introducer axis and the mallet face, relative to the introducer strike face, was misaligned by a mean angle of 15.2° from the introducer strike face. Conclusion. The direction of the impact vector in manual impaction lacks both accuracy and precision. There is an opportunity to improve this through more advanced impaction instruments or surgical training. Cite this article: Bone Joint Res 2024;13(4):193–200

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

Aims. A significant reduction in wear at five and ten years was previously reported when comparing Durasul highly cross-linked polyethylene with nitrogen-sterilized Sulene polyethylene in total hip arthroplasty (THA). We investigated whether the improvement observed at the earlier follow-up continued, resulting in decreased osteolysis and revision surgery rates over the second decade. Methods. Between January 1999 and December 2001, 90 patients underwent surgery using the same acetabular and femoral components with a 28 mm metallic femoral head and either a Durasul or Sulene liner. A total of 66 hips of this prospective randomized study were available for a minimum follow-up of 20 years. The linear femoral head penetration rate was measured at six weeks, one year, and annually thereafter, using the Dorr method on digitized radiographs with a software package. Results. In the Durasul group, no patients underwent revision due to loosening or showed radiological evidence of osteolysis. In the Sulene group, four patients (four hips) were revised due to femoral component loosening. The 20-year cumulative failure incidence in the presence of the competing event of death for revision surgery was 4.5% (95% confidence interval (CI) 0.8 to 13.6) in the Durasul group, and 8.9% (95% CI 2.8 to 19.5) in the Sulene group. The mean wear one year after surgery was 0.09 mm (SD 0.007) in the Durasul group and 0.24 (SD 0.015) in the Sulene group (p < 0.001). From one to 20 years after surgery, the mean total penetration was 0.32 mm (SD 0.045) in the Durasul group and 1.07 mm (SD 0.13) in the Sulene group (p < 0.001). Mean femoral head penetration at 20 years was approximately 70.0% less in the Durasul group than the Sulene group. Conclusion. The significant reduction in femoral head penetration obtained with the Durasul compared with Sulene in uncemented THA resulted in lower osteolysis and revision rates after 20 years. Cite this article: Bone Joint J 2022;104-B(9):1032–1038

Aims. Femoral component anteversion is an important factor in the success of total hip arthroplasty (THA). This retrospective study aimed to investigate the accuracy of femoral component anteversion with the Mako THA system and software using the Exeter cemented femoral component, compared to the Accolade II cementless femoral component. Methods. We reviewed the data of 30 hips from 24 patients who underwent THA using the posterior approach with Exeter femoral components, and 30 hips from 24 patients with Accolade II components. Both groups did not differ significantly in age, sex, BMI, bone quality, or disease. Two weeks postoperatively, CT images were obtained to measure acetabular and femoral component anteversion. Results. The mean difference in femoral component anteversion between intraoperative and postoperative CT measurements (system accuracy of component anteversion) was 0.8° (SD 1.8°) in the Exeter group and 2.1° (SD 2.3°) in the Accolade II group, respectively (p = 0.020). The mean difference in anteversion between the plan and the postoperative CT measurements (clinical accuracy of femoral component anteversion) was 1.2° (SD 3.6°) in the Exeter group, and 4.2° (SD 3.9°) in the Accolade II group (p = 0.003). No significant differences were found in acetabular component inclination and anteversion; however, the clinical accuracy of combined anteversion was significantly better in the Exeter group (0.6° (SD 3.9°)) than the Accolade II group (3.6° (SD 4.1°)). Conclusion. The Mako THA system and software helps surgeons control the femoral component anteversion to achieve the target angle of insertion. The Exeter femoral component, inserted using Mako THA system, showed greater precision for femoral component and combined component anteversion than the Accolade II component. Cite this article: Bone Joint J 2024;106-B(3 Supple A):104–109

Aims. Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. Methods. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements. Results. Strong correlations were observed for all EOS measurements (r. s. > 0.9). The strongest correlation with AP radiograph (inter-teardrop line) was observed for functional-ASIS-to-floor (functional) (r. s. = 0.57), much weaker than the correlations between EOS measurements. ASIS-to-ankle measurements exhibited a high correlation to other linear measurements and the highest ICC (r. s. = 0.97). Using anterior superior iliac spine (ASIS)-to-ankle, 33% of patients had an absolute LLD of greater than 10 mm, which was statistically different from the inter-teardrop LLD measurement (p < 0.005). Discussion. We found that the conventional measurement of LLD on AP pelvic radiograph does not correlate well with long leg measurements and may not provide a true appreciation of LLD. ASIS-to-ankle demonstrated improved detection of potential LLD than other EOS and radiograph measurements. Full length, functional imaging methods may become the new gold standard to measure LLD. Cite this article: Bone Jt Open 2022;3(12):960–968

Aims. The aim of this study was to explore the functional results in a fitter subgroup of participants in the Hip Fracture Evaluation with Alternatives of Total Hip Arthroplasty versus Hemiarthroplasty (HEALTH) trial to determine whether there was an advantage of total hip arthroplasty (THA) versus hemiarthroplasty (HA) in this population. Methods. We performed a post hoc exploratory analysis of a fitter cohort of patients from the HEALTH trial. Participants were aged over 50 years and had sustained a low-energy displaced femoral neck fracture (FNF). The fittest participant cohort was defined as participants aged 70 years or younger, classified as American Society of Anesthesiologists grade I or II, independent walkers prior to fracture, and living at home prior to fracture. Multilevel models were used to estimate the effect of THA versus HA on functional outcomes. In addition, a sensitivity analysis of the definition of the fittest participant cohort was performed. Results. There were 143 patients included in the fittest cohort. Mean age was 66 years (SD 4.5) and 103 were female (72%). No clinically relevant differences were found between the treatment groups in the primary and sensitivity analyses. Conclusion. This analysis found no differences in functional outcomes between HA and THA within two years of displaced low-energy FNF in a subgroup analysis of the fittest HEALTH patients. These findings suggest that very few patients above 50 years of age benefit in a clinically meaningful way from a THA versus a HA early after injury. Cite this article: Bone Jt Open 2022;3(8):611–617

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