Aims. The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy. Methods. We included patients who underwent THA using Wagner Cone due to proximal femur anatomical abnormalities between August 2014 and January 2019 at a single institution. We investigated implant survival time using the endpoint of dislocation and revision, and compared the prevalence of prosthetic impingements between the Wagner Cone, a tapered cone stem, and the Taperloc, a tapered wedge stem, through simulation. We also collected Oxford Hip Score (OHS), visual analogue scale (VAS) satisfaction, and VAS pain by postal survey in August 2023 and explored variables associated with those scores. Results. Of the 58 patients (62 hips), two (two hips) presented with dislocation or reoperation, and Kaplan-Meier analysis indicated a five-year survival rate of 96.7% (95% CI 92.4 to 100). Mean stem anteversion was 35.2° (SD 18.2°) for the Taperloc stem and 29.8° (SD 7.9°) for the Wagner Cone stem; mean reduction from Taperloc to Wagner Cone was 5.4° (SD 18.8°). Overall, 55 hips (52 patients) were simulated, and the prevalence of prosthetic impingement was lower for the Wagner Cone (5.5%, 3/55) compared with the Taperloc (20.0%, 11/55) stem, with an odds ratio of 0.20 (p = 0.038). Among the 33 respondents to the postal survey (36 hips), the mean scores were VAS pain 10.9, VAS satisfaction 86.9, and OHS 44.7. A multivariable analysis revealed that reduction of stem anteversion from Taperloc to Wagner Cone was more favourable for VAS pain (p = 0.029) and VAS satisfaction (p = 0.002). Conclusion. The mid-term survival rate for THA using the Wagner Cone stem was high, which may be supported by a reduction in prosthetic impingement. The reduction in excessive stem anteversion by using a tapered cone stem was associated with reduced pain and increased patient satisfaction. Cite this article: Bone Jt Open 2024;5(10):858–867

Aims. Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model. Methods. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed. Results. In flexion, an overall impingement rate of 2.3% was detected for flexed-seated, squatting, forward-bending, and criss-cross-sitting positions, and 4.7% for the ankle-over-knee position. In extension, most hips (60.5%) were found to impinge at or prior to 50° of external rotation (pivoting). Many of these impingement events were due to a prominent ischium. The mean maximum external rotation prior to impingement was 45.9° (15° to 80°) and 57.9° (20° to 90°) prior to prosthetic impingement. No impingement was found in standing, sitting, crossing ankles, seiza, and downward dog. Conclusion. This study demonstrated that positions of daily living tested in a CT-based 3D model show high rates of impingement. Simulating additional positions through 3D modelling is a low-cost method of potentially improving outcomes without compromising patient safety. By incorporating CT-based 3D modelling of positions of daily living into routine preoperative protocols for THA, there is the potential to lower the risk of postoperative impingement events. Cite this article: Bone Jt Open 2023;4(6):416–423

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

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Prior cost-effectiveness analyses on osseointegrated prosthesis for transfemoral unilateral amputees have analyzed outcomes in non-USA countries using generic quality of life instruments, which may not be appropriate when evaluating disease-specific quality of life. These prior analyses have also focused only on patients who had failed a socket-based prosthesis. The aim of the current study is to use a disease-specific quality of life instrument, which can more accurately reflect a patient’s quality of life with this condition in order to evaluate cost-effectiveness, examining both treatment-naïve and socket refractory patients.

Aims. Periprosthetic hip-joint infection is a multifaceted and highly detrimental outcome for patients and clinicians. The incidence of prosthetic joint infection reported within two years of primary hip arthroplasty ranges from 0.8% to 2.1%. Costs of treatment are over five-times greater in people with periprosthetic hip joint infection than in those with no infection. Currently, there are no national evidence-based guidelines for treatment and management of this condition to guide clinical practice or to inform clinical study design. The aim of this study is to develop guidelines based on evidence from the six-year INFection and ORthopaedic Management (INFORM) research programme. Methods. We used a consensus process consisting of an evidence review to generate items for the guidelines and online consensus questionnaire and virtual face-to-face consensus meeting to draft the guidelines. Results. The consensus panel comprised 21 clinical experts in orthopaedics, primary care, rehabilitation, and healthcare commissioning. The final output from the consensus process was a 14-item guideline. The guidelines make recommendations regarding increased vigilance and monitoring of those at increased risk of infection; diagnosis including strategies to ensure the early recognition of prosthetic infection and referral to orthopaedic teams; treatment, including early use of DAIR and revision strategies; and postoperative management including appropriate physical and psychological support and antibiotic strategies. Conclusion. We believe the implementation of the INFORM guidelines will inform treatment protocols and clinical pathways to improve the treatment and management of periprosthetic hip infection. Cite this article: Bone Jt Open 2023;4(4):226–233

Aims. The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems. Methods. A systematic literature search was performed adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. In parallel, we performed a retrospective single centre study of Exeter V40 femoral stem prosthetic fractures between April 2003 and June 2020. Results. There are 25 reported cases of such prosthetic fractures confined to small case series and case reports within the literature. We report an additional 19 cases to the literature (mean age 66.3 years (SD 11.7); 12 (63%) females; BMI 32.9 kg/m. 2. (SD 5.9)). The mean time from index procedure to fracture was 7.8 years (SD 3.6; 2.5 to 16.3). Exeter V40 stem fracture incidence was 0.15% and 1.21% for primary and revision arthroplasty, respectively. Incidence was significantly higher in revision arthroplasty (p < 0.001) and 125 mm length stems compared to ≥ 150 mm length stems (1.25% vs 0.13%, respectively; p < 0.001). When comparing different stem length cohorts, 125 mm short-stems were associated with stem-body fractures (92% vs 29%; p = 0.0095), earlier time to fracture (6.2 years vs 11.0 years; p = 0.0018), younger patient age at time of fracture (62.7 years vs 72.6 years; p = 0.037), and female sex (75% vs 43%; p = 0.326). Conclusion. This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. Short 125 mm length Exeter V40 stems undoubtedly have a role in restoring anatomy and biomechanics in smaller femoral geometries, although the surgeon has to appreciate the higher risk of stem fracture and the associated predisposing factors which may necessitate particular attention to surgical technique and planning. Cite this article: Bone Jt Open 2021;2(6):443–456

Aims. The aims of this study were to: 1) report on a cohort of skeletally mature patients with native hip and knee septic arthritis over a 14-year period; 2) to determine the rate of joint failure in patients who had experienced an episode of hip or knee septic arthritis; and 3) to assess the outcome following septic arthritis relative to the infecting organism, whether those patients infected by Staphylococcus aureus would be more likely to have adverse outcomes than those infected by other organisms. Methods. All microbiological samples from joint aspirations between March 2000 and December 2014 at our institution were reviewed in order to identify cases of culture-proven septic arthritis. Cases in children (aged < 16 years) and prosthetic joints were excluded. Data were abstracted on age at diagnosis, sex, joint affected (hip or knee), type of organisms isolated, cause of septic arthritis, comorbidities within the Charlson Comorbidity Index (CCI), details of treatment, and outcome. Results. A total of 142 patients were confirmed to have had an episode of septic arthritis in a native hip (n = 17) or knee joint (n = 125). S. aureus accounted for 57.7% of all hip and knee joint infections. There were 13 inpatient deaths attributed to septic arthritis. The median age of the patients who died was 77.5 (46.9 to 92.2) and their median age-adjusted CCI was 8 (6 to 12). A failure of the joint occurred in 26 knees (21%) and nine hips (53%). Of the knee joints infected by S. aureus (n = 71), 23 knees (32%) went into failure of joint, whereas of those infected by other organisms (n = 54), only three knees (6%) failed. Conclusion. Based on our study findings, hip and knee septic arthritis long-term outcomes were substantially worse than their immediate outcome suggested. Failure of knee joint is 6.1 times more likely to occur in those infected with S. aureus. Cite this article: Bone Jt Open 2024;5(9):785–792

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Unicompartmental knee arthroplasty (UKA) is the preferred treatment for anterior medial knee osteoarthritis (OA) owing to the rapid postoperative recovery. However, the risk factors for UKA failure remain controversial.

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For rare cases when a tumour infiltrates into the hip joint, extra-articular resection is required to obtain a safe margin. Endoprosthetic reconstruction following tumour resection can effectively ensure local control and improve postoperative function. However, maximizing bone preservation without compromising surgical margin remains a challenge for surgeons due to the complexity of the procedure. The purpose of the current study was to report clinical outcomes of patients who underwent extra-articular resection of the hip joint using a custom-made osteotomy guide and 3D-printed endoprosthesis.

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Safety concerns surrounding osseointegration are a significant barrier to replacing socket prosthesis as the standard of care following limb amputation. While implanted osseointegrated prostheses traditionally occur in two stages, a one-stage approach has emerged. Currently, there is no existing comparison of the outcomes of these different approaches. To address safety concerns, this study sought to determine whether a one-stage osseointegration procedure is associated with fewer adverse events than the two-staged approach.

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Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies.

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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.

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The standard of surgical treatment for lower limb neoplasms had been characterized by highly interventional techniques, leading to severe kinetic impairment of the patients and incidences of phantom pain. Rotationplasty had arisen as a potent limb salvage treatment option for young cancer patients with lower limb bone tumours, but its impact on the gait through comparative studies still remains unclear several years after the introduction of the procedure. The aim of this study is to assess the effect of rotationplasty on gait parameters measured by gait analysis compared to healthy individuals.

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The aim of this study was to investigate the safety and efficacy of 3D-printed modular prostheses in patients who underwent joint-sparing limb salvage surgery (JSLSS) for malignant femoral diaphyseal bone tumours.

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Using data from the Hip Fracture Evaluation with Alternatives of Total Hip Arthroplasty versus Hemiarthroplasty (HEALTH) trial, we sought to determine if a difference in functional outcomes exists between monopolar and bipolar hemiarthroplasty (HA).

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The proximal tibia (PT) is the anatomical site most frequently affected by primary bone tumours after the distal femur. Reconstruction of the PT remains challenging because of the poor soft-tissue cover and the need to reconstruct the extensor mechanism. Reconstructive techniques include implantation of massive endoprosthesis (megaprosthesis), osteoarticular allografts (OAs), or allograft-prosthesis composites (APCs).

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The purpose of this study is to report our updated results at a minimum follow-up of 30 years using a first generation uncemented tapered femoral component in primary total hip arthroplasty (THA).

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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.

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To review the evidence and reach consensus on recommendations for follow-up after total hip and knee arthroplasty.

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The metabolic equivalent of task (MET) score examines patient performance in relation to energy expenditure before and after knee arthroplasty. This study assesses its use in a knee arthroplasty population in comparison with the widely used Oxford Knee Score (OKS) and EuroQol five-dimension index (EQ-5D), which are reported to be limited by ceiling effects.