Aims. Young adults undergoing total hip arthroplasty (THA) largely have different indications for surgery, preoperative function, and postoperative goals compared to a standard patient group. The aim of our study was to describe young adult THA preoperative function and quality of life, and to assess postoperative satisfaction and compare this with functional outcome measures. Methods. A retrospective cohort analysis of young adults (aged < 50 years) undergoing THA between May 2018 and May 2023 in a single tertiary centre was undertaken. Median follow-up was 31 months (12 to 61). Oxford Hip Score (OHS) and focus group-designed questionnaires were distributed. Searches identified 244 cases in 225 patients. Those aged aged under 30 years represented 22.7% of the cohort. Developmental dysplasia of the hip (50; 45.5%) and Perthes’ disease (15; 13.6%) were the commonest indications for THA. Results. Preoperatively, of 110 patients, 19 (17.2%) were unable to work before THA, 57 (52%) required opioid analgesia, 51 (46.4%) were reliant upon walking aids, and 70 (63.6%) had sexual activity limited by their pathology. One patient required revision due to instability. Mean OHS was 39 (9 to 48). There was a significant difference between the OHS of cases where THA met expectation, compared with the OHS when it did not (satisfied: 86 (78.2%), OHS: 41.2 (36.1%) vs non-satisfied: 24 (21%), OHS: 31.6; p ≤ 0.001). Only one of the 83 patients (75.5%) who returned to premorbid levels of activity did so after 12 months. Conclusion. Satisfaction rates of THA in young adults is high, albeit lower than commonly quoted figures. Young adults awaiting THA have poor function with high requirements for mobility aids, analgesia, and difficulties in working and undertaking leisure activities. The OHS provided a useful insight into patient function and was predictive of satisfaction rates, although it did not address the specific demands of young adults undertaking THA. Function at one year postoperatively is a good indication of overall outcomes. Cite this article: Bone Jt Open 2024;5(4):304–311

Aims. Psychological status may be an important predictor of outcome after periacetabular osteotomy (PAO). The aim of this study was to investigate the influence of psychological distress on postoperative health-related quality of life, joint function, self-assessed pain, and sports ability in patients undergoing PAO. Methods. In all, 202 consecutive patients who underwent PAO for developmental dysplasia of the hip (DDH) at our institution from 2015 to 2017 were included and followed up at 63 months (SD 10) postoperatively. Of these, 101 with complete data sets entered final analysis. Patients were assessed by questionnaire. Psychological status was measured by Brief Symptom Inventory (BSI-18), health-related quality of life was raised with 36-Item Short Form Survey (SF-36), hip functionality was measured by the short version 0f the International Hip Outcome Tool (iHOT-12), Subjective Hip Value (SHV), and Hip Disability and Outcome Score (HOS). Surgery satisfaction and pain were assessed. Dependent variables (endpoints) were postoperative quality of life (SF-36, HOS quality of life (QoL)), joint function (iHOT-12, SHV, HOS), patient satisfaction, and pain. Psychological distress was assessed by the Global Severity Index (GSI), somatization (BSI Soma), depression (BSI Depr), and anxiety (BSI Anx). Influence of psychological status was assessed by means of univariate and multiple multivariate regression analysis. Results. In multiple multivariate regression, postoperative GSI, BSI Soma, and BSI Depr had a negative effect on postoperative SF-36 (e -2.07, -3.05, and -2.67, respectively; p < 0.001), iHOT-12 (e -1.35 and -4.65, respectively; p < 0.001), SHV (e -1.20 and -2.71, respectively; p < 0.001), HOS QoL (e -2.09 and -4.79, respectively; p < 0.001), HOS Function (e -1.00 and -3.94, respectively; p < 0.001), and HOS Sport (e -1.44 and -5.29, respectively; p < 0.001), and had an effect on postoperative pain (e 0.13 and 0.37, respectively; p < 0.001). Conclusion. Psychological distress, depression, and somatization disorders affect health-related quality of life, perceived joint function, and sports ability. Pain perception is significantly increased by somatization. However, patient satisfaction with surgery is not affected. Cite this article: Bone Jt Open 2023;4(10):758–765

Aims. The primary aim of our study was to assess the influence of age on hip-specific outcome following total hip arthroplasty (THA). Secondary aims were to assess health-related quality of life (HRQoL) and level of activity according to age. Methods. A prospective cohort study was conducted. All patients were fitted with an Exeter stem with a 32 mm head on highly cross-linked polyethylene (X3RimFit) cemented acetabulum. Patients were recruited into three age groups: < 65 years, 65 to 74 years, and ≥ 75 years, and assessed preoperatively and at three, 12, 24, and 60 months postoperatively. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), and Hip disability and Osteoarthritis Outcome Score (HOOS), were used to assess hip-specific outcome. EuroQol five-dimension five-level questionnaire (EQ-5D-5L) and 36-Item Short Form Survey (SF-36) scores were used to assess HRQoL. The Lower Extremity Activity Scale (LEAS) and Timed Up and Go (TUG) were used to assess level of activity. Results. There were no significant (p > 0.05) differences in the WOMAC scores, HSS, HOOS, or EQ-5D-5L at any postoperative timepoint between the age groups. Patients aged ≥ 75 years had significantly lower physical function (p ≤ 0.010) and physical role (p ≤ 0.047) SF-36 scores at 12, 24, and 60 months, but were equal to that expect of an age-matched population. No differences according to age were observed for the other six domains of the SF-36 (p > 0.060). The ≥ 75 years group had a lower LEAS (p < 0.001) and longer TUG test times (p ≤ 0.032) compared to the < 65 years group, but older age groups had significant (p < 0.001) improvement relative to their preoperative baseline measures. Conclusion. Age did not influence postoperative hip-specific outcome or HRQoL (according to the EQ-5D) following THA. Despite a significant improvement, older patients had lower postoperative activity levels compared to younger patients, but this may be reflective of the overall physical effect of ageing. Cite this article: Bone Jt Open 2022;3(9):692–700

Aims. The primary aim of this study was to compare the hip-specific functional outcome of robotic assisted total hip arthroplasty (rTHA) with manual total hip arthroplasty (mTHA) in patients with osteoarthritis (OA). Secondary aims were to compare general health improvement, patient satisfaction, and radiological component position and restoration of leg length between rTHA and mTHA. Methods. A total of 40 patients undergoing rTHA were propensity score matched to 80 patients undergoing mTHA for OA. Patients were matched for age, sex, and preoperative function. The Oxford Hip Score (OHS), Forgotten Joint Score (FJS), and EuroQol five-dimension questionnaire (EQ-5D) were collected pre- and postoperatively (mean 10 months (SD 2.2) in rTHA group and 12 months (SD 0.3) in mTHA group). In addition, patient satisfaction was collected postoperatively. Component accuracy was assessed using Lewinnek and Callanan safe zones, and restoration of leg length were assessed radiologically. Results. There were no significant differences in the preoperative demographics (p ≥ 0.781) or function (p ≥ 0.383) between the groups. The postoperative OHS (difference 2.5, 95% confidence interval (CI) 0.1 to 4.8; p = 0.038) and FJS (difference 21.1, 95% CI 10.7 to 31.5; p < 0.001) were significantly greater in the rTHA group when compared with the mTHA group. However, only the FJS was clinically significantly greater. There was no difference in the postoperative EQ-5D (difference 0.017, 95% CI -0.042 to 0.077; p = 0.562) between the two groups. No patients were dissatisfied in the rTHA group whereas six were dissatisfied in the mTHA group, but this was not significant (p = 0.176). rTHA was associated with an overall greater rate of component positioning in a safe zone (p ≤ 0.003) and restoration of leg length (p < 0.001). Conclusion. Patients undergoing rTHA had a greater hip-specific functional outcome when compared to mTHA, which may be related to improved component positioning and restoration of leg length. However, there was no difference in their postoperative generic health or rate of satisfaction. Cite this article: Bone Joint Res 2021;10(1):22–30

Aims. The Patient-Reported Outcomes Measurement Information System (PROMIS) has demonstrated faster administration, lower burden of data capture and reduced floor and ceiling effects compared to traditional Patient Reported Outcomes Measurements (PROMs). We investigated the suitability of PROMIS Mobility score in assessing physical function in the sequelae of childhood hip disease. Methods. In all, 266 adolscents (aged ≥ 12 years) and adults were identified with a prior diagnosis of childhood hip disease (either Perthes’ disease (n = 232 (87.2%)) or Slipped Capital Femoral Epiphysis (n = 34 (12.8%)) with a mean age of 27.73 years (SD 12.24). Participants completed the PROMIS Mobility Computer Adaptive Test, the Non-Arthritic Hip Score (NAHS), EuroQol five-dimension five-level questionnaire, and the Numeric Pain Rating Scale. We investigated the correlation between the PROMIS Mobility and other tools to assess use in this population and any clustering of outcome scores. Results. There was a strong correlation between the PROMIS Mobility and other established PROMs; NAHS (rs = 0.79; p < 0.001). There was notable clustering in PROMIS at the upper end of the distribution score (42.5%), with less seen in the NAHS (20.3%). However, the clustering was broadly similar between PROMIS Mobility and the comparable domains of the NAHS; function (53.6%), and activity (35.0%). Conclusion. PROMIS Mobility strongly correlated with other tools demonstrating convergent construct validity. There was clustering of physical function scores at the upper end of the distributions, which may reflect truncation of the data caused by participants having excellent outcomes. There were elements of disease not captured within PROMIS Mobility alone, and difficulties in differentiating those with the highest levels of function. Cite this article: Bone Jt Open 2021;2(12):1089–1095

Aims. To establish the survivorship, function, and metal ion levels in an unselected series of metal-on-metal hip resurfacing arthroplasties (HRAs) performed by a non-designer surgeon. Methods. We reviewed 105 consecutive HRAs in 83 patients, performed by a single surgeon, at a mean follow-up of 14.9 years (9.3 to 19.1). The cohort included 45 male and 38 female patients, with a mean age of 49.5 years (SD 12.5). Results. At the time of review 13 patients with 15 hips had died from causes unrelated to the hip operation, and 14 hips had undergone revision surgery, giving an overall survival rate of rate of 86.7% (95% confidence interval (CI) 84.2 to 89.1). The survival rate in men was 97.7% (95% CI 96.3 to 98.9) and in women was 73.4% (95% CI 70.6 to 75.1). The median head size of the failed group was 42 mm (interquartile range (IQR) 42 to 44), and in the surviving group was 50 mm (IQR 46 to 50). In all, 13 of the 14 revised hips had a femoral component measuring ≤ 46 mm. The mean blood levels of cobalt and chromium ions were 26.6 nmol/l (SD 24.5) and 30.6 nmol/l (SD 15.3), respectively. No metal ion levels exceeded the safe limit. The mean Oxford Hip Score was 41.5 (SD 8.9) and Harris Hip Score was 89.9 (14.8). In the surviving group, four patients had radiolucent lines around the stem of the femoral component, and one had lysis around the acetabular component; eight hips demonstrated heterotopic ossification. Conclusion. Our results confirm the existing understanding that HRA provides good long-term survival and function in patients with adequate-sized femoral heads. This is evidenced by a 97.7% survival rate among men (larger heads) in our series at a mean follow-up of 14.9 years. Failure is closely related to head sizes ≤ 46 cm. Cite this article: Bone Jt Open 2022;3(1):68–76

Aims. Golf is a popular pursuit among those requiring total hip arthroplasty (THA). The aim of this study was to determine if participating in golf is associated with greater functional outcomes, satisfaction, or improvement in quality of life (QoL) compared to non-golfers. Methods. All patients undergoing primary THA over a one-year period at a single institution were included with one-year postoperative outcomes. Patients were retrospectively followed up to assess if they had been golfers at the time of their surgery. Multivariate linear regression analysis was performed to assess the independent association of preoperative golfing status on outcomes. Results. The study cohort consisted of a total of 308 patients undergoing THA, of whom 44 were golfers (14%). This included 120 male patients (39%) and 188 female patients (61%), with an overall mean age of 67.8 years (SD 11.6). Golfers had a greater mean postoperative Oxford Hip Score (OHS) (3.7 (95% confidence interval (CI) 1.9 to 5.5); p < 0.001) and EuroQol visual analogue scale (5.5 (95% CI 0.1 to 11.9); p = 0.039). However, there were no differences in EuroQoL five-dimension score (p = 0.124), pain visual analogue scale (p = 0.505), or Forgotten Joint Score (p = 0.215). When adjusting for confounders, golfers had a greater improvement in their Oxford Hip Score (2.7 (95% CI 0.2 to 5.3); p < 0.001) compared to non-golfers. Of the 44 patients who reported being golfers at the time of their surgery, 32 (72.7%) returned to golf and 84.4% of those were satisfied with their involvement in golf following surgery. Those who returned to golf were more likely to be male (p = 0.039) and had higher (better) preoperative health-related QoL (p = 0.040) and hip-related functional scores (p = 0.026). Conclusion. Golfers had a greater improvement in their hip-specific function compared to non-golfers after THA. However, less than three-quarters of patients return to golf, with male patients and those who had greater preoperative QoL or hip-related function being more likely to return to play. Cite this article: Bone Jt Open 2022;3(2):145–151

Objective. The objective of this study was to explore dimensionality of the Oxford Hip Score (OHS) and examine whether self-reported pain and functioning can be distinguished in the form of subscales. Methods. This was a secondary data analysis of the UK NHS hospital episode statistics/patient-reported outcome measures dataset containing pre-operative OHS scores on 97 487 patients who were undergoing hip replacement surgery. . Results. The proposed number of factors to extract depended on the method of extraction employed. Velicer’s Minimum Average Partial test and the Parallel Analysis suggested one factor, the Cattell’s scree test and Kaiser-over-1 rule suggested two factors. Exploratory factor analysis demonstrated that the two-factor OHS had most of the items saliently loading either of the two factors. These factors were named ‘Pain’ and ‘Function’ and their respective subscales were created. There was some cross-loading of items: 8 (pain on standing up from a chair) and 11 (pain during work). These items were assigned to the ‘Pain’ subscale. The final ‘Pain’ subscale consisted of items 1, 8, 9, 10, 11 and 12. The ‘Function’ subscale consisted of items 2, 3, 4, 5, 6 and 7, with the recommended scoring of the subscales being from 0 (worst) to 100 (best). Cronbach’s alpha was 0.855 for the ‘Pain’ subscale and 0.861 for the ‘Function’ subscale. A confirmatory factor analysis demonstrated that the two-factor model of the OHS had a better fit. However, none of the one-factor or two-factor models was rejected. Conclusion. Factor analyses demonstrated that, in addition to current usage as a single summary scale, separate information on pain and self-reported function can be extracted from the OHS in a meaningful way in the form of subscales. Cite this article: Bone Joint Res 2014;3:305–9

Objectives

The purpose of this study was to investigate whether the femoral head–neck contour, characterised by the alpha angle, varies with the stage of physeal maturation using MRI evaluation of an asymptomatic paediatric population.

Aims. The aim of this study was to assess the clinical and radiological results of patients who were revised using a custom-made triflange acetabular component (CTAC) for component loosening and pelvic discontinuity (PD) after previous total hip arthroplasty (THA). Methods. Data were extracted from a single centre prospective database of patients with PD who were treated with a CTAC. Patients were included if they had a follow-up of two years. The Hip Disability and Osteoarthritis Outcome Score (HOOS), modified Oxford Hip Score (mOHS), EurQol EuroQoL five-dimension three-level (EQ-5D-3L) utility, and Numeric Rating Scale (NRS), including visual analogue score (VAS) for pain, were gathered at baseline, and at one- and two-year follow-up. Reasons for revision, and radiological and clinical complications were registered. Trends over time are described and tested for significance and clinical relevance. Results. A total of 18 females with 22 CTACs who had a mean age of 73.5 years (SD 7.7) were included. A significant improvement was found in HOOS (p < 0.0001), mOHS (p < 0.0001), EQ-5D-3L utility (p = 0.003), EQ-5D-3L NRS (p = 0.013), VAS pain rest (p = 0.008), and VAS pain activity (p < 0.0001) between baseline and final follow-up. Minimal clinically important improvement in mOHS and the HOOS Physical Function Short Form (HOOS-PS) was observed in 16 patients (73%) and 14 patients (64%), respectively. Definite healing of the PD was observed in 19 hips (86%). Complications included six cases with broken screws (27%), four cases (18%) with bony fractures, and one case (4.5%) with sciatic nerve paresthesia. One patient with concurrent bilateral PD had revision surgery due to recurrent dislocations. No revision surgery was performed for screw failure or implant breakage. Conclusion. CTAC in patients with THA acetabular loosening and PD can result in stable constructs and significant improvement in functioning and health-related quality of life at two years' follow-up. Further follow-up is necessary to determine the mid- to long-term outcome. Cite this article: Bone Jt Open 2023;4(2):53–61

Aims. Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. Methods. We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures. Results. Mean follow-up was 39.5 months (36 to 71), with a significant improvement in post-revision function compared to preoperative function. Graft site remodelling was rated radiologically as moderate in 31 hips (63%) and strong in 12 hips (24%). There were no cases of complete graft site dissolution. No acetabular loosening was identified. None of the patients developed clinically significant heterotopic ossification. There were twelve reoperations: six patients developed post-revision infections, three experienced dislocations, two sustained periprosthetic femur fractures, and one subject had femoral component aseptic loosening. Conclusion. Our series reports bone defect restoration with the sole use of a biphasic injectable BGS in the periacetabular region. We did not observe significant graft dissolution. We emphasize that successful graft site remodelling requires meticulous recipient site preparation. Cite this article: Bone Jt Open 2022;3(12):991–997

Aims. The Single Assessment Numerical Evalution (SANE) score is a pragmatic alternative to longer patient-reported outcome measures (PROMs). The purpose of this study was to investigate the concurrent validity of the SANE and hip-specific PROMs in a generalized population of patients with hip pain at a single timepoint upon initial visit with an orthopaedic surgeon who is a hip preservation specialist. We hypothesized that SANE would have a strong correlation with the 12-question International Hip Outcome Tool (iHOT)-12, the Hip Outcome Score (HOS), and the Hip disability and Osteoarthritis Outcome Score (HOOS), providing evidence for concurrent validity of the SANE and hip-specific outcome measures in patients with hip pain. Methods. This study was a cross-sectional retrospective database analysis at a single timepoint. Data were collected from 2,782 patients at initial evaluation with a hip preservation specialist using the iHOT-12, HOS, HOOS, and SANE. Outcome scores were retrospectively analyzed using Pearson correlation coefficients. Results. Mean raw scores were iHOT-12 67.01 (SD 29.52), HOS 58.42 (SD 26.26), HOOS 86.85 (SD 32.94), and SANE 49.60 (SD 27.92). SANE was moderately correlated with the iHOT-12 (r = -0.4; 95% CI -0.35 to -0.44; p < 0.001), HOS (r = 0.57; 95% CI 0.53 to 0.60; p < 0.001), and HOOS (r = -0.55; 95% CI -0.51 to -0.58; p < 0.001). The iHOT-12 and HOOS were recorded as a lower score, indicating better function, which accounts for the negative r values. Conclusion. This study was the first to investigate the relationship between the SANE and the iHOT-12, HOS, and HOOS in a population of patients with hip pain at the initial evaluation with an orthopaedic surgeon, and found moderate correlation between SANE and the iHOT-12, HOS, and HOOS. The SANE may be a pragmatic alternative for clinical benchmarking in a general population of patients with hip pain. The construct validity of the SANE should be questioned compared to legacy measures whose content validity has been more rigorously investigated. Cite this article: Bone Jt Open 2024;5(10):904–910

Aims. Cementing in arthroplasty for hip fracture is associated with improved postoperative function, but may have an increased risk of early mortality compared to uncemented fixation. Quantifying this mortality risk is important in providing safe patient care. This study investigated the association between cement use in arthroplasty and mortality at 30 days and one year in patients aged 50 years and over with hip fracture. Methods. This retrospective cohort study used linked data from the Australian Hip Fracture Registry and the National Death Index. Descriptive analysis and Kaplan-Meier survival curves tested the unadjusted association of mortality between cemented and uncemented procedures. Multilevel logistic regression, adjusted for covariates, tested the association between cement use and 30-day mortality following arthroplasty. Given the known institutional variation in preference for cemented fixation, an instrumental variable analysis was also performed to minimize the effect of unknown confounders. Adjusted Cox modelling analyzed the association between cement use and mortality at 30 days and one year following surgery. Results. The 30-day mortality was 6.9% for cemented and 4.9% for uncemented groups (p = 0.003). Cement use was significantly associated with 30-day mortality in the Kaplan-Meier survival curve (p = 0.003). After adjusting for covariates, no significant association between cement use and 30-day mortality was shown in the adjusted multilevel logistic regression (odd rati0 (OR) 1.1, 95% confidence interval (CI) 0.9 to 1.5; p = 0.366), or in the instrumental variable analysis (OR 1.0, 95% CI 0.9 to 1.0, p=0.524). There was no significant between-group difference in mortality within 30days (hazard ratio (HR) 0.9, 95% CI 0.7to 1.1; p = 0.355) or one year (HR 0.9 95% CI 0.8 to 1.1; p = 0.328) in the Cox modelling. Conclusion. No statistically significant difference in patient mortality with cement use in arthroplasty was demonstrated in this population, once adjusted for covariates. This study concludes that cementing in arthroplasty for hip fracture is a safe means of surgical fixation. Cite this article: Bone Jt Open 2023;4(3):198–204

Aims. In order to release the contracture band completely without damaging normal tissues (such as the sciatic nerve) in the surgical treatment of gluteal muscle contracture (GMC), we tried to display the relationship between normal tissue and contracture bands by magnetic resonance neurography (MRN) images, and to predesign a minimally invasive surgery based on the MRN images in advance. Methods. A total of 30 patients (60 hips) were included in this study. MRN scans of the pelvis were performed before surgery. The contracture band shape and external rotation angle (ERA) of the proximal femur were also analyzed. Then, the minimally invasive GMC releasing surgery was performed based on the images and measurements, and during the operation, incision lengths, surgery duration, intraoperative bleeding, and complications were recorded; the time of the first postoperative off-bed activity was also recorded. Furthermore, the patients’ clinical functions were evaluated by means of Hip Outcome Score (HOS) and Ye et al’s objective assessments, respectively. Results. The contracture bands exhibited three typical types of shape – feather-like, striped, and mixed shapes – in MR images. Guided by MRN images, we designed minimally invasive approaches directed to each hip. These approaches resulted in a shortened incision length in each hip (0.3 cm (SD 0.1)), shorter surgery duration (25.3 minutes (SD 5.8)), less intraoperative bleeding (8.0 ml (SD 3.6)), and shorter time between the end of the operation and the patient’s first off-bed activity (17.2 hours (SD 2.0)) in each patient. Meanwhile, no serious postoperative complications occurred in all patients. The mean HOS-Sports subscale of patients increased from 71.0 (SD 5.3) to 94.83 (SD 4.24) at six months postoperatively (p < 0.001). The follow-up outcomes from all patients were “good” and “excellent”, based on objective assessments. Conclusion. Preoperative MRN analysis can be used to facilitate the determination of the relationship between contracture band and normal tissues. The minimally invasive surgical design via MRN can avoid nerve damage and improve the release effect. Cite this article: Bone Jt Open 2024;5(9):776–784

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. Although the Fitmore Hip Stem has been on the market for almost 15 years, it is still not well documented in randomized controlled trials. This study compares the Fitmore stem with the CementLeSs (CLS) in several different clinical and radiological aspects. The hypothesis is that there will be no difference in outcome between stems. Methods. In total, 44 patients with bilateral hip osteoarthritis were recruited from the outpatient clinic at a single tertiary orthopaedic centre. The patients were operated with bilateral one-stage total hip arthroplasty. The most painful hip was randomized to either Fitmore or CLS femoral component; the second hip was operated with the femoral component not used on the first side. Patients were evaluated at three and six months and at one, two, and five years postoperatively with patient-reported outcome measures, radiostereometric analysis, dual-energy X-ray absorptiometry, and conventional radiography. A total of 39 patients attended the follow-up visit at two years (primary outcome) and 35 patients at five years. The primary outcome was which hip the patient considered to have the best function at two years. Results. At two and five years, more patients considered the hip with the CLS femoral component as superior but without a statistically significant difference. There were no differences in clinical outcome, magnitude of femoral component migration, or change of bone mineral density at five years. At three months, the Fitmore femoral component had subsided a median -0.71 mm (interquartile range (IQR) -1.67 to -0.20) and the CLS femoral component -0.70 mm (IQR -1.53 to -0.17; p = 0.742). In both groups the femoral head centre had migrated posteriorly (Fitmore -0.17 mm (IQR -0.98 to -0.04) and CLS -0.23 mm (IQR -0.87 to 0.07; p = 0.936)). After three months neither of the femoral components showed much further migration. During the first postoperative year, one Fitmore femoral component was revised due to aseptic loosening. Conclusion. Up to five years, we found no statistically significant difference in outcomes between the Fitmore and the CLS femoral components. The slightly worse outcomes, including one revised hip because of loosening, speaks against the hypothesis that the Fitmore femoral component should be advantageous compared to the CLS if more patients had been recruited to this study. Cite this article: Bone Jt Open 2023;4(5):306–314

Aims. The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance. Methods. A prospective cohort study was conducted with 101 patients with end-stage hip OA scheduled for THA (mean age 67.4 years (SD 9.5), 51.5% female (n = 52)). Patients were assessed at baseline as well as after three and months. Primary outcome was cognitive performance measured by d2 Test of Attention at six months, Trail Making Test (TMT), FAS-test, Rivermead Behavioural Memory Test (RBMT; story recall subtest), and Rey-Osterrieth Complex Figure Test (ROCF). The improvement of cognitive performance was analyzed using repeated measures analysis of variance. Results. At six months, there was significant improvement in attention, working speed and concentration (d2-test; p < 0.001), visual construction and visual memory (ROCF; p < 0.001), semantic memory (FAS-test; p = 0.009), verbal episodic memory (RBMT; immediate recall p = 0.023, delayed recall p = 0.026), as well as pain (p < 0.001) with small to large effect sizes. Attention, concentration, and visual as well as verbal episodic memory improved significantly with medium effect sizes over η. 2. partial. = 0.06. In these cognitive domains the within-group difference exceeded the minimum clinically important difference. Conclusion. THA is associated with clinically relevant postoperative improvement in the cognitive functions of attention, concentration, and memory. These data support the concept of a broad interaction of arthroplasty with central nervous system function. Cite this article: Bone Joint J 2022;104-B(3):331–340

Aims. Post-traumatic periprosthetic acetabular fractures are rare but serious. Few studies carried out on small cohorts have reported them in the literature. The aim of this work is to describe the specific characteristics of post-traumatic periprosthetic acetabular fractures, and the outcome of their surgical treatment in terms of function and complications. Methods. Patients with this type of fracture were identified retrospectively over a period of six years (January 2016 to December 2021). The following data were collected: demographic characteristics, date of insertion of the prosthesis, details of the intervention, date of the trauma, characteristics of the fracture, and type of treatment. Functional results were assessed with the Harris Hip Score (HHS). Data concerning complications of treatment were collected. Results. Our series included 20 patients, with a mean age of 77 years (46 to 90). All the patients had at least one comorbid condition. Radiographs showed that 75% of the fractures were pure transverse fractures, and a transverse component was present in 90% of patients. All our patients underwent surgical treatment: open reduction and internal fixation, revision of the acetabular component, or both. Mean follow-up was 24 months, and HHS at last follow-up was 75.5 (42 to 95). The principal complications observed were dislocations of the prosthesis (30%) and infections (20%). A need for revision surgery was noted in 30% of patients. No dislocation occurred in patients undergoing osteosynthesis with acetabular reconstruction. We did not note either mechanical loosening of the acetabular component nor thromboembolic complications. In all, 30% of patients presented acute anemia requiring transfusion, and one death was reported. Conclusion. Post-traumatic periprosthetic acetabular fractures frequently have a transverse component that can destabilize the acetabular implant. The frequency of complications, principally dislocations, led to a high rate of revision surgery. Improvements in preoperative planning should make it possible to codify management to reduce this high rate of complications. The best results were obtained when the surgical strategy combined osteosynthesis with acetabular reconstruction. Cite this article: Bone Jt Open 2024;5(1):28–36

Aims. The primary aim of this study was to determine the ten-year outcome following surgical treatment for femoroacetabular impingement (FAI). We assessed whether the evolution of practice from open to arthroscopic techniques influenced outcomes and tested whether any patient, radiological, or surgical factors were associated with outcome. Methods. Prospectively collected data of a consecutive single-surgeon cohort, operated for FAI between January 2005 and January 2015, were retrospectively studied. The cohort comprised 393 hips (365 patients; 71% male (n = 278)), with a mean age of 34.5 years (SD 10.0). Over the study period, techniques evolved from open surgical dislocation (n = 94) to a combined arthroscopy-Hueter technique (HA + Hueter; n = 61) to a pure arthroscopic technique (HA; n = 238). Outcome measures of interest included modes of failures, complications, reoperation, and patient-reported outcome measures (PROMs). Demographic, radiological, and surgical factors were tested for possible association with outcome. Results. At a mean follow-up of 7.5 years (SD 2.5), there were 43 failures in 38 hips (9.7%), with 35 hips (8.9%) having one failure mode, one hip (0.25%) having two failure modes, and two hips (0.5%) having three failure modes. The five- and ten-year hip joint preservation rates were 94.1% (SD 1.2%; 95% confidence interval (CI) 91.8 to 96.4) and 90.4% (SD 1.7%; 95% CI 87.1 to 93.7), respectively. Inferior survivorship was detected in the surgical dislocation group. Age at surgery, Tönnis grade, cartilage damage, and absence of rim-trimming were associated with improved preservation rates. Only Tönnis grade was an independent predictor of hip preservation. All PROMs improved postoperatively. Factors associated with improvement in PROMs included higher lateral centre-edge and α angles, and lower retroversion index and BMI. Conclusion. FAI surgery provides lasting improvement in function and a joint preservation rate of 90.4% at ten years. The evolution of practice was not associated with inferior outcome. Since degree of arthritis is the primary predictor of outcome, improved awareness and screening may lead to prompt intervention and better outcomes. Cite this article: Bone Jt Open 2022;3(10):804–814

Aims. In the native hip, the hip capsular ligaments tighten at the limits of range of hip motion and may provide a passive stabilizing force to protect the hip against edge loading. In this study we quantified the stabilizing force vectors generated by capsular ligaments at extreme range of motion (ROM), and examined their ability to prevent edge loading. Methods. Torque-rotation curves were obtained from nine cadaveric hips to define the rotational restraint contributions of the capsular ligaments in 36 positions. A ligament model was developed to determine the line-of-action and effective moment arms of the medial/lateral iliofemoral, ischiofemoral, and pubofemoral ligaments in all positions. The functioning ligament forces and stiffness were determined at 5 Nm rotational restraint. In each position, the contribution of engaged capsular ligaments to the joint reaction force was used to evaluate the net force vector generated by the capsule. Results. The medial and lateral arms of the iliofemoral ligament generated the highest inbound force vector in positions combining extension and adduction providing anterior stability. The ischiofemoral ligament generated the highest inbound force in flexion with adduction and internal rotation (FADIR), reducing the risk of posterior dislocation. In this position the hip joint reaction force moved 0.8° inbound per Nm of internal capsular restraint, preventing edge loading. Conclusion. The capsular ligaments contribute to keep the joint force vector inbound from the edge of the acetabulum at extreme ROM. Preservation and appropriate tensioning of these structures following any type of hip surgery may be crucial to minimizing complications related to joint instability. Cite this article: Bone Joint Res 2021;10(9):594–601