Aims. Dislocation is a major concern following total hip arthroplasty (THA) for osteoarthritis (OA). Both dual-mobility components and standard acetabular components with large femoral heads are used to reduce the risk of dislocation. We investigated whether dual-mobility components are superior to standard components in reducing the two-year dislocation and revision risk in a propensity-matched sample from the Danish Hip Arthroplasty Register (DHR). Methods. This population-based cohort study analyzed data from the DHR and the Danish National Patient Register. We included all patients undergoing primary THA for OA from January 2010 to December 2019 with either dual-mobility or standard acetabular components with metal-on-polyethylene or ceramic-on-polyethylene articulations with a 36 mm femoral head. The samples were propensity score-matched on patient and implant characteristics. The primary outcome was the difference in the absolute risk of dislocation within two years, with a secondary outcome of the difference in the absolute risk of revision surgery of any cause within the same timeframe. The cumulative incidence of dislocation was calculated using the Aalen-Johansen estimator, while the difference in absolute risk was estimated using absolute risk regression (ARR). Results. We included 4,499 patients with dual-mobility components and 4,499 patients with standard components after propensity score-matching. Both groups had a mean age of 75 years (SD 8.5), included approximately 60% females, and had a two-year survival of 95.3% (95% CI 94.6 to 95.9). The dual-mobility group was 80% less likely to dislocate within two years (ARR 0.20 (95% CI 0.14 to 0.28); p < 0.001), with no significant difference in the risk of revision compared to standard components (ARR 1.15 (95% CI 0.89 to 1.48); p = 0.293). Conclusion. Dual-mobility components are associated with a reduced risk of dislocation and with no significant difference in the risk of revision for any cause within two years of THA when compared to standard acetabular components with 36 mm femoral heads. Cite this article: Bone Joint J 2025;107-B(1):50–57

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The purpose of this study was to directly compare the Modular Dual Mobility (MDM) Mobile Bearing Hip System (Stryker, USA) and large femoral heads (LFHs) in revision total hip arthroplasties (THAs) at mid-term follow-up, with specific emphasis on survival free of re-revision for dislocation, any re-revision, dislocation, and the risk of metal-related complications.

Aims. Overall sagittal flexion is restricted in patients who have undergone both lumbar fusion and total hip arthroplasty (THA). However, it is not evident to what extent this movement is restricted in these patients and how this influences quality of life (QoL). The purpose of this study was to determine the extent to which hip-lumbar mobility is decreased in these patients, and how this affects their QoL score. Methods. Patients who underwent primary THA at our hospital between January 2010 and March 2021 were considered (n = 976). Among them, 44 patients who underwent lumbar fusion were included as cases, and 44 THA patients without lumbar disease matched by age, sex, and BMI as Control T. Among those who underwent lumbar fusion, 44 patients without hip abnormalities matched by age, sex, and BMI to the cases were considered as Control F. Outcome and spinopelvic parameters were measured radiologically in extension and flexed-seated positions. Hip, lumbar, and hip-lumbar mobility were calculated as parameter changes between positions. Results. There were 20 male and 112 female patients in the case and control groups, with a mean age of 77 years (5 to 94) and a mean BMI of 24 kg/m. 2. (15 to 34). QoL score and hip-lumbar mobility were reduced in cases compared to Control T and F, and were further reduced as the number of fused levels increased. Hip-lumbar mobility was associated with reduction in activity-related QoL, mostly for those activities requiring sagittal flexion. Conclusion. This study confirmed that hip-lumbar mobility is a factor that influences activity, most of all those requiring overall sagittal flexion. Clinicians should focus on hip-lumbar mobility and counteract disability by suggesting appropriate assistive devices. Cite this article: Bone Joint J 2025;107-B(1):34–41

Aims. Excellent outcomes have been reported following CT-based robotic arm-assisted total hip arthroplasty (rTHA) compared with manual THA; however, its superiority over CT-based navigation THA (nTHA) remains unclear. This study aimed to determine whether a CT-based robotic arm-assisted system helps surgeons perform accurate cup placement, minimizes leg length, and offsets discrepancies more than a CT-based navigation system. Methods. We studied 60 hips from 54 patients who underwent rTHA between April 2021 and August 2023, and 45 hips from 44 patients who underwent nTHA between January 2020 and March 2021 with the same target cup orientation at the Department of Orthopedic Surgery at Ozu Memorial Hospital, Japan. After propensity score matching, each group had 37 hips. Postoperative acetabular component position and orientation were measured using the planning module of the CT-based navigation system. Postoperative leg length and offset discrepancies were evaluated using postoperative CT in patients who have unilateral hip osteoarthritis. Results. The absolute differences in radiological inclination (RI) and radiological anteversion (RA) from the target were significantly smaller in rTHA (RI 1.2° (SD 1.2°), RA 1.4° (SD 1.2°)) than in nTHA (RI 2.7° (SD 1.9°), RA 3.0° (SD 2.6°)) (p = 0.005 for RI, p = 0.002 for RA). The absolute distance of the target’s postoperative centre of rotation was significantly smaller in the mediolateral (ML) and superoinferior (SI) directions in rTHA (ML 1.1 mm (SD 0.8), SI 1.3 mm (SD 0.5)) than in nTHA (ML 1.9 mm (SD 0.9), SI 1.6 mm (SD 0.9)) (p = 0.002 for ML, p = 0.042 for SI). Absolute leg length and absolute discrepancies in the acetabular, femoral, and global offsets were significantly lower in the rTHA group than in the nTHA group (p = 0.042, p = 0.004, p = 0.003, and p = 0.010, respectively). In addition, the percentage of hips significantly differed with an absolute global offset discrepancy of ≤ 5 mm (p < 0.001). Conclusion. rTHA is more accurate in cup orientation and position than nTHA, effectively reducing postoperative leg length and offset discrepancy. Cite this article: Bone Jt Open 2024;6(1):3–11

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The Clavien-Dindo (CD) classification and Comprehensive Complication Index (CCI) have been validated primarily among general surgical procedures. To date, the validity of these measures has not been assessed in patients undergoing arthroplasty.

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We evaluated the national and regional trends from 2013 to 2022, in the prevalence of Perthes’ disease among adolescent males in South Korea.

Aims. Arthroplasty has been shown to generate the most waste among all orthopaedic subspecialties, and it is estimated that hip and knee arthroplasty generate in excess of three million kg of waste annually in the UK. Infectious waste generates up to ten times more CO2 compared with recycled waste, and previous studies have shown that over 90% of waste in the infectious stream is misallocated. We assessed the effect of real-time waste segregation by an unscrubbed team member on waste generation in knee and hip arthroplasty cases, and compared this with a simple educational intervention during the ‘team brief’ at the start of the operating list across two sites. Methods. Waste was categorized into five categories: infectious, general, recycling, sharps, and linens. Each category was weighed at the end of each case using a digital weighing scale. At Site A (a tertiary orthopaedic hospital), pre-intervention data were collected for 16 total knee arthroplasy (TKA) and 15 total hip arthroplasty (THA) cases. Subsequently, for ten TKA and ten THA cases, an unscrubbed team member actively segregated waste in real-time into the correct streams. At Site B (a district general hospital), both pre- and post-intervention groups included ten TKA and ten THA cases. The intervention included reminding staff during the ‘team brief’ to segregate waste correctly. Results. Active real-time waste segregation reduced infectious waste by a mean of 2.51 kg (95% CI 1.492 to 3.542) in TKA, and 1.83 kg in THA cases (p = 0.004). Educational intervention reduced infectious waste by a mean of 3.52 kg in TKA and 2.09 kg in THA cases (p = 0.026). Total waste was significantly reduced in both groups post-intervention for TKA cases. Conclusion. Simple educational measures alone can significantly reduce the amount of infectious waste. Extrapolated nationally, our results would yield a reduction of approximately 315,004 kg to 594,577 kg of CO2 annually, which equates to 70 to 132 gasoline-powered passenger vehicles driven for a year. Cite this article: Bone Jt Open 2024;5(12):1119–1124

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This meta-analysis and systematic review aimed to comprehensively investigate the effects of vitamin K supplementation on bone mineral density (BMD) at various sites and bone metabolism in middle-aged and older adults.

Aims. Better prediction of outcome after total hip arthroplasty (THA) is warranted. Systemic inflammation and central neuroinflammation are possibly involved in progression of osteoarthritis and pain. We explored whether inflammatory biomarkers in blood and cerebrospinal fluid (CSF) were associated with clinical outcome, and baseline pain or disability, 12 months after THA. Methods. A total of 50 patients from the Danish Pain Research Biobank (DANPAIN-Biobank) between January and June 2018 were included. Postoperative outcome was assessed as change in Oxford Hip Score (OHS) from baseline to 12 months after THA, pain was assessed on a numerical rating scale, and disability using the Pain Disability Index. Multiple regression models for each clinical outcome were included for biomarkers in blood and CSF, respectively, including age, sex, BMI, and Kellgren-Lawrence score. Results. Change in OHS was associated with blood concentrations of tumour necrosis factor (TNF), interleukin-8 (IL-8), interleukin-6 receptor (IL-6R), glycoprotein 130 (gp130), and IL-1β (R. 2. = 0.28, p = 0.006), but not with CSF biomarkers. Baseline pain was associated with blood concentrations of lymphotoxin alpha (LTα), TNFR1, TNFR2, and IL-6R (R. 2. = 0.37, p < 0.001) and CSF concentrations of TNFR1, TNFR2, IL-6, IL-6R, and IL-1Ra (R. 2. = 0.40, p = 0.001). Baseline disability was associated with blood concentrations of TNF, LTα, IL-8, IL-6, and IL-1α (R. 2. = 0.53, p < 0.001) and CSF concentrations of gp130, TNF, and IL-1β (R. 2. = 0.26, p = 0.002). Thus, preoperative systemic low-grade inflammation predicted 12-month postoperative outcome after THA, and was associated with preoperative pain and disability. Conclusion. This study highlights the importance of systemic inflammation in osteoarthritis, and presents a possible path for better patient selection for THA in the future. Preoperative central neuroinflammation was associated with preoperative pain and disability, but not change in OHS after THA. Cite this article: Bone Joint Res 2024;13(12):741–749

The December 2024 Arthroplasty Roundup³⁶⁰ looks at: Aspirin for hip and knee arthroplasty?; VTE prophylaxis; VTE prophylaxis part II.

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This study aimed to determine clinical outcomes; relationships between postoperative anterior, lateral, and posterior acetabular coverage and joint survival; and prognostic factors for joint survival after transposition osteotomy of the acetabulum (TOA).

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Cutibacterium acnes (C. acnes; previously known as Propionibacterium acnes or P. acnes) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee.

Hip fractures pose a major global health challenge, leading to high rates of morbidity and mortality, particularly among the elderly. With an ageing population, the incidence of these injuries is rising, exerting significant pressure on healthcare systems worldwide. Despite substantial research aimed at establishing best practice, several key areas remain the subject of ongoing debate. This article examines the latest evidence on the place of arthroplasty in the surgical treatment of hip fractures, with a particular focus on the choice of implant, the use of cemented versus uncemented fixation, and advances in perioperative care.

Cite this article: Bone Joint J 2024;106-B(12):1372–1376.

Aims. Day-case knee and hip replacement, in which patients are discharged on the day of surgery, has been gaining popularity during the last two decades, and particularly since the COVID-19 pandemic. This systematic review presents the evidence comparing day-case to inpatient-stay surgery. Methods. A systematic literature search was performed of MEDLINE, Embase, and grey literature databases to include all studies which compare day-case with inpatient knee and hip replacement. Meta-analyses were performed where appropriate using a random effects model. The protocol was registered prospectively (PROSPERO CRD42023392811). Results. A total of 38 studies were included, with a total of 83,888 day-case procedures. The studies were predominantly from the USA and Canada, observational, and with a high risk of bias. Day-case patients were a mean of 2.08 years younger (95% CI 1.05 to 3.12), were more likely to be male (odds ratio (OR) 1.3 (95% CI 1.19 to 1.41)), and had a lower mean BMI and American Society of Anesthesiologists grades compared with inpatients. Overall, day-case surgery was associated with significantly lower odds of readmission (OR 0.83 (95% CI 0.73 to 0.96); p = 0.009), subsequent emergency department attendance (OR 0.62 (95% CI 0.48 to 0.79); p < 0.001), and complications (OR 0.7 (95% CI 0.55 to 0.89) p = 0.004), than inpatient surgery. There were no significant differences in the rates of reoperation or mortality. The overall rate of successful same-day discharge for day-case surgery was 85% (95% CI 81 to 88). Patient-reported outcome measures and cost-effectiveness were either equal or favoured day-case. Conclusion. Within the limitations of the literature, in particular the substantial risk of selection bias, the outcomes following day-case knee and hip replacement appear not to be inferior to those following an inpatient stay. The evidence is more robust for unicompartmental knee replacement (UKR) than for total knee replacement (TKR) or total hip replacement (THR). The rate of successful same-day discharge is highest in UKR, followed by TKR and comparatively lower in THR. Cite this article: Bone Joint J 2024;106-B(12):1385–1392

The December 2024 Hip & Pelvis Roundup. 360. looks at: Total hip arthroplasty after femoral neck fractures versus osteoarthritis at one-year follow-up: a comparative, retrospective study; Excellent mid-term survival of a monoblock conical prosthesis in treating atypical and complex femoral anatomy with total hip arthroplasty; Hip arthroscopy for femoroacetabular impingement improves sexual function; Fast-track hip arthroplasty does not increase complication rates; Ten-year experience with same-day discharge outpatient total hip arthroplasty: patient demographics changed, but safe outcomes were maintained

The December 2024 Children’s orthopaedics Roundup³⁶⁰ looks at: Establishing best practice for managing idiopathic toe walking in children: a UK consensus; Long-term outcomes of below-elbow casting in paediatric diaphyseal forearm fractures; Residual dysplasia risk persists in developmental dysplasia of the hip patients after Pavlik harness treatment; 3D printing in paediatricorthopaedics: enhancing surgical efficiency and patient outcomes; Pavlik harness treatment for hip dysplasia does not delay motor skill development in children; High prevalence of hip dysplasia found in adolescents with idiopathic scoliosis on routine spine radiographs; Minifragment plates as effective growth modulation for ulnar deformities of the distal radius in children; Long-term success of Chiari pelvic osteotomy in preserving hip function: 30-year follow-up study.

Aims. For displaced femoral neck fractures (FNFs) in geriatric patients, there remains uncertainty regarding the effect of total hip arthroplasty (THA) compared with hemiarthroplasty (HA) in the guidelines. We aimed to compare 90-day surgical readmission, in-hospital complications, and charges between THA and HA in these patients. Methods. The Hospital Quality Monitoring System was queried from 1 January 2013 to 31 December 2019 for displaced FNFs in geriatric patients treated with THA or HA. After propensity score matching, which identified 33,849 paired patients, outcomes were compared between THA and HA using logistic and linear regression models. Results. The HA group had a lower incidence of 90-day surgical readmission than the THA group (odds ratio (OR) 0.75 (95% CI 0.68 to 0.83)). Meanwhile, the HA group had lower incidence of dislocation (OR 0.42 (95% CI 0.33 to 0.52)), aseptic loosening (OR 0.50 (95% CI 0.38 to 0.66)), and joint pain (OR 0.63 (95% CI 0.40 to 0.98)), but a higher incidence of periprosthetic fracture (OR 1.41 (95% CI 1.07 to 1.87)) for readmission, compared to the THA group. The incidence of in-hospital complications did not differ significantly between the two groups. Moreover, the HA group had lower mean charges than the THA group (47,578.29 Chinese Yuan (CNY) (SD 20,069.71) vs 57,641.00 CNY (SD 21,524.07)). Conclusion. When considering 90-day surgical readmission rate, in-hospital complications, and mortality, HA resulted in a significantly lower surgical readmission rate within 90 days compared to THA, despite the patients being older and having a higher Charlson Comorbidity Index. Cite this article: Bone Joint J 2024;106-B(12):1477–1484

Aims. Highly cross-linked polyethylene (HXLPE) greatly reduces wear in total hip arthroplasty, compared to conventional polyethylene (CPE). Cross-linking is commonly achieved by irradiation. This study aimed to compare the degree of cross-linking and in vitro wear rates across a cohort of retrieved and unused polyethylene cups/liners from various brands. Methods. Polyethylene acetabular cups/liners were collected at one centre from 1 April 2021 to 30 April 2022. The trans-vinylene index (TVI) and oxidation index (OI) were determined by Fourier-transform infrared spectrometry. Wear was measured using a pin-on-disk test. Results. A total of 47 specimens from ten brands were included. The TVI was independent of time in vivo. A linear correlation (R. 2. = 0.995) was observed between the old and current TVI standards, except for vitamin E-containing polyethylene. The absorbed irradiation dose calculated from the TVI corresponded to product specifications for all but two products. For one electron beam-irradiated HXLPE, a mean dose of 241% (SD 18%) of specifications was determined. For another, gamma-irradiated HXLPE, a mean 41% (SD 13%) of specifications was determined. Lower wear was observed for higher TVI. Conclusion. The TVI is a reliable measure of the absorbed irradiation dose and does not alter over time in vivo. The products of various brands differ by manufacturing details and consequently cross-linking characteristics. Absorption and penetration of electron radiation and gamma radiation differ, potentially leading to higher degrees of cross-linking for electron radiation. There is a non-linear, inverse correlation between TVI and in vitro wear. The wear resistance of the HXLPE with low TVI was reduced and more comparable to CPE. Cite this article: Bone Joint Res 2024;13(11):682–693

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The mechanism by which synovial fluid (SF) kills bacteria has not yet been elucidated, and a better understanding is needed. We sought to analyze the antimicrobial properties of exogenous copper in human SF against Staphylococcus aureus.