Aims

Revision hip arthroplasty for femoral stem loosening remains challenging due to significant bone loss and deformities requiring specialized revision stems. The aim of this study was to evaluate the clinical and radiological outcomes, and survival, of a consecutive series of femoral revisions performed using a primary cementless stem with tapered geometry and rectangular cross-section at medium-term follow-up.

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Valgus subsidence of uncemented tibial components following medial unicompartmental knee arthroplasty (UKA) poses a challenge in the early postoperative phase, necessitating a comprehensive understanding of its prevalence, risk factors, and impact on patient outcomes.

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Unicompartmental knee arthroplasty (UKA) is associated with an accelerated recovery, improved functional outcomes, and retention of anatomical knee kinematics when compared to manual total knee arthroplasty (mTKA). UKA is not universally employed by all surgeons as there is a higher revision risk when compared to mTKA. Robotic arm-assisted (ra) UKA enables the surgeon to position the prosthesis more accurately when compared to manual UKA, and is associated with improved functional outcomes and a lower early revision risk. Non-randomized data suggests that, when compared to mTKA, raUKA has a clinically meaningful greater functional benefit. This protocol describes a randomized controlled trial that aims to evaluate the clinical and cost-effectiveness of raUKA compared to mTKA for individuals with isolated medial compartment osteoarthritis (OA).

Aims. This study aimed to investigate whether the use of CT-based navigation enhances: 1) the accuracy of cup placement; and 2) the achievement rate of required range of motion (ROM). Additionally, we investigated the impact of using a large femoral head and dual-mobility liner on the achievement rates. Methods. This retrospective study analyzed 60 manual and 51 CT-based navigated primary total hip arthroplasties performed at a single facility. Postoperative CT scans and CT-based simulation software were employed to measure the cup orientation and to simulate the ROM. We compared the absolute errors for radiological inclination (RI) and radiological anteversion (RA) between the two groups. We also examined whether the simulated ROM met the required ROM criteria, defined as flexion > 110°, internal rotation > 30°, extension > 30°, and external rotation > 30°. Furthermore, we performed simulations with 36 mm femoral head and dual-mobility liner. Results. The absolute errors of RI and RA from the preoperative plan were significantly smaller in the CT-based navigation group (3.7° (SD 3.5°) vs 5.1° (SD 3.5°); p = 0.022, and 3.9° (SD 3.5°) vs 6.8° (SD 5.0°); p = 0.001, respectively). The proportion of cases achieving the required ROM in all directions was significantly higher in the CT-based navigation group (42% vs 63%; p = 0.036). The achievement rates of the required ROM were significantly higher with the use of a 36 mm ball or dual-mobility liner compared to the use of a 32 mm ball (65% vs 51%; p = 0.040 and 77% vs 51%; p ≤ 0.001, respectively). Conclusion. CT-based navigation enhanced required ROM achievement rates by > 20%, regardless of the ball diameter. The improved accuracy of cup placement through CT-based navigation likely contributed to the enhancement. Furthermore, the use of large femoral heads and dual-mobility liners also improved the required ROM achievement rates. In cases with a high risk of dislocation, use of these devices is preferred. Cite this article: Bone Jt Open 2025;6(2):155–163

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Machine learning (ML) holds significant promise in optimizing various aspects of total shoulder arthroplasty (TSA), potentially improving patient outcomes and enhancing surgical decision-making. The aim of this systematic review was to identify ML algorithms and evaluate their effectiveness, including those for predicting clinical outcomes and those used in image analysis.

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Autologous bone graft (ABG) is considered the ‘gold standard’ among graft materials for bone regeneration. However, complications including limited availability, donor site morbidity, and deterioration of regenerative capacity over time have been reported. P-15 is a synthetic peptide that mimics the cell binding domain of Type-I collagen. This peptide stimulates new bone formation by enhancing osteogenic cell attachment, proliferation, and differentiation. The objective of this study was to conduct a systematic literature review to determine the clinical efficacy and safety of P-15 peptide in bone regeneration throughout the skeletal system.

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Sagittal lumbar pelvic alignment alters with posterior pelvic tilt (PT) following total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH). The individual value of pelvic sagittal inclination (PSI) following rebalancing of lumbar-pelvic alignment is unknown. In different populations, PT regresses in a linear relationship with pelvic incidence (PI). PSI and PT have a direct relationship to each other via a fixed individual angle ∠γ. This study aimed to investigate whether the new PI created by acetabular component positioning during THA also has a linear regression relationship with PT/PSI when lumbar-pelvic alignment rebalances postoperatively in patients with Crowe type III/IV DDH.

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To evaluate how fore- and midfoot coronal plane alignment differs in feet with hallux valgus (HV), using 3DCT when measured in standard weightbearing (SWB) versus sesamoid view (SV) position, and to determine whether first metatarsophalangeal (MTP) dorsiflexion affects the relationship between the first metatarsal (M1) head and the sesamoid bones.

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The Birmingham Orthopaedic Oncology Meeting (BOOM), held in January 2024, convened 309 delegates from 53 countries to discuss and refine 21 consensus statements on the optimal management of chondrosarcoma.

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The aim of the present study was to analyze the oncological and neurological outcome of patients undergoing interdisciplinary treatment for primary malignant bone and soft-tissue tumours of the spine within the last seven decades, and changes over time.

Aims. The development of lumbar lordosis has been traditionally examined using angular measurements of the spine to reflect its shape. While studies agree regarding the increase in the angles during growth, the growth rate is understudied, and sexual dimorphism is debated. In this study, we used a novel method to estimate the shape of the lumbar curve (LC) using the landmark-based geometric morphometric method to explore changes in LC during growth, examine the effect of size and sex on LC shape, and examine the associations between angular measurements and shape. Methods. The study population included 258 children aged between 0 and 20 years (divided into five age groups) who underwent a CT scan between the years 2009 and 2019. The landmark-based geometric morphometric method was used to capture the LC shape in a sagittal view. Additionally, the lordosis was measured via Cobb and sacral slope angles. Multivariate and univariate statistical analyses were carried out to examine differences in shape between males and females and between the age groups. Results. The overall shape of the LC overlapped between males and females in most age groups, except for the nine- to 12-year age group. However, size did not affect LC shape. LC shape changed significantly during growth from straight to curved, reaching its mature shape earlier in females. This corresponded with the results obtained by the lordosis and sacral slope angles. A significant positive correlation was found between the LC shape and angles, although the angles demonstrated poor distinction between age groups, as opposed to the LC shape. Conclusion. New insights into LC shape development were achieved using the geometric morphometric method. The LC shape was sex-independent in most age groups. However, the LC reached its mature shape earlier in females than males. The method and data of this study are beneficial for future studies examining aetiological factors for spinal pathologies and maldevelopment. Cite this article: Bone Joint Res 2025;14(1):58–68

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This study was performed to investigate the association between the acetabular morphology and the joint space narrowing rate (JSNR) in the non-arthritic hip.

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The aim of this study was to report long-term clinical outcomes of a modern convertible metal-backed glenoid (MBG) in total shoulder arthroplasty (TSA).

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The aim of this study was to evaluate the radiological outcome of patients with large bone defects in the femur and tibia who were treated according to the guidelines of the diamond concept in our department (Centre for Orthopedics, Trauma Surgery, and Paraplegiology).

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The “2 to 10% strain rule” for fracture healing has been widely interpreted to mean that interfragmentary strain greater than 10% predisposes a fracture to nonunion. This interpretation focuses on the gap-closing strain (axial micromotion divided by gap size), ignoring the region around the gap where osteogenesis typically initiates. The aim of this study was to measure gap-closing and 3D interfragmentary strains in plated ovine osteotomies and associate local strain conditions with callus mineralization.

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 involvement of long non-coding RNA (lncRNA) in bone marrow mesenchymal stem cell (MSC) osteogenic differentiation during osteoporosis (OP) development has attracted much attention. In this study, we aimed to disclose how LINC01089 functions in human mesenchymal stem cell (hMSC) osteogenic differentiation, and to study the mechanism by which LINC01089 regulates MSC osteogenesis.

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Functional alignment (FA) in total knee arthroplasty (TKA) aims to achieve balanced gaps by adjusting implant positioning while minimizing changes to constitutional joint line obliquity (JLO). Although FA uses kinematic alignment (KA) as a starting point, the final implant positions can vary significantly between these two approaches. This study used the Coronal Plane Alignment of the Knee (CPAK) classification to compare differences between KA and final FA positions.

Aims. The transepicondylar axis is a well-established reference for the determination of femoral component rotation in total knee arthroplasty (TKA). However, when severe bone loss is present in the femoral condyles, rotational alignment can be more complicated. There is a lack of validated landmarks in the supracondylar region of the distal femur. Therefore, the aim of this study was to analyze the correlation between the surgical transepicondylar axis (sTEA) and the suggested dorsal cortex line (DCL) in the coronal plane and the inter- and intraobserver reliability of its CT scan measurement. Methods. A total of 75 randomly selected CT scans were measured by three experienced surgeons independently. The DCL was defined in the coronal plane as a tangent to the dorsal femoral cortex located 75 mm above the joint line in the frontal plane. The difference between sTEA and DCL was calculated. Descriptive statistics and angulation correlations were generated for the sTEA and DCL, as well as for the distribution of measurement error for intra- and inter-rater reliability. Results. The external rotation of the DCL to the sTEA was a mean of 9.47° (SD 3.06°), and a median of 9.2° (IQR 7.45° to 11.60°), with a minimum value of 1.7° and maximum of 16.3°. The measurements of the DCL demonstrated very good to excellent test-retest and inter-rater reliability coefficients (intraclass correlation coefficient 0.80 to 0.99). Conclusion. This study reveals a correlation between the sTEA and the DCL. Overall, 10° of external rotation of the dorsal femoral cortical bone to the sTEA may serve as a reliable landmark for initial position of the femoral component. Surgeons should be aware that there are outliers in this study in up to 17% of the measurements, which potentially could result in deviations of femoral component rotation. Cite this article: Bone Jt Open 2024;5(12):1067–1071

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Frailty has been gathering attention as a factor to predict surgical outcomes. However, the association of frailty with postoperative complications remains controversial in spinal metastases surgery. We therefore designed a prospective study to elucidate risk factors for postoperative complications with a focus on frailty.