Aims. It has been hypothesized that proximal radial neck resorption (PRNR) following press-fit radial head arthroplasty (RHA) is due to stress-shielding. We compared two different press-fit stems by means of radiographs to investigate whether the shape and size of the stems are correlated with the degree of PRNR. Methods. The radiographs of 52 RHAs were analyzed both at 14 days postoperatively and after two years. A cylindrical stem and a conical stem were implanted in 22 patients (group 1) and 30 patients (group 2), respectively. The PRNR was measured in the four quadrants of the radial neck and the degree of stem filling was calculated by analyzing the ratio between the prosthetic stem diameter (PSD) and the medullary canal diameter (MCD) at the proximal portion of the stem (level A), halfway along the stem length (level B), and distally at the stem tip (level C). Results. Overall, 50 of the 52 patients displayed PRNR. The mean PRNR observed was 3.9 mm (0 to 7.4). The degree of endomedullary stem filling at levels A, B, and C was 96%, 90%, and 68% in group 1, and 96%, 72%, and 57%, in group 2, with differences being significant at levels B (p < 0.001) and C (p < 0.001). No significant correlations emerged between the severity of PRNR and the three stem/canal ratios either within each group or between the groups. Conclusion. PRNR in press-fit RHA appears to be independent of the shape and size of the stems. Other causes besides stem design should be investigated to explain completely this phenomenon. Cite this article: Bone Joint J 2021;103-B(3):530–535

Aims. The diagnosis of joint infections is an inexact science using combinations of blood inflammatory markers and microscopy, culture, and sensitivity of synovial fluid (SF). There is potential for small molecule metabolites in infected SF to act as infection markers that could improve accuracy and speed of detection. The objective of this study was to use nuclear magnetic resonance (NMR) spectroscopy to identify small molecule differences between infected and noninfected human SF. Methods. In all, 16 SF samples (eight infected native and prosthetic joints plus eight noninfected joints requiring arthroplasty for end-stage osteoarthritis) were collected from patients. NMR spectroscopy was used to analyze the metabolites present in each sample. Principal component analysis and univariate statistical analysis were undertaken to investigate metabolic differences between the two groups. Results. A total of 16 metabolites were found in significantly different concentrations between the groups. Three were in higher relative concentrations (lipids, cholesterol, and N-acetylated molecules) and 13 in lower relative concentrations in the infected group (citrate, glycine, glycosaminoglycans, creatinine, histidine, lysine, formate, glucose, proline, valine, dimethylsulfone, mannose, and glutamine). Conclusion. Metabolites found in significantly greater concentrations in the infected cohort are markers of inflammation and infection. They play a role in lipid metabolism and the inflammatory response. Those found in significantly reduced concentrations were involved in carbohydrate metabolism, nucleoside metabolism, the glutamate metabolic pathway, increased oxidative stress in the diseased state, and reduced articular cartilage breakdown. This is the first study to demonstrate differences in the metabolic profile of infected and noninfected human SF, using a noninfected matched cohort, and may represent putative biomarkers that form the basis of new diagnostic tests for infected SF. Cite this article: Bone Joint Res 2021;10(1):85–95

Aims. To investigate the experience and emotional impact of prosthetic joint infection (PJI) on orthopaedic surgeons and identify holistic strategies to improve the management of PJI and protect surgeons’ wellbeing. Methods. In total, 18 prosthetic joint surgeons in Sweden were recruited using a purposive sampling strategy. Content analysis was performed on transcripts of individual in-person interviews conducted between December 2017 and February 2018. Results. PJI had a negative emotional impact on Swedish surgeons. Many felt guilt, stress, and a sense of failure, and several aspects of PJI management were associated with psychosocial challenges. Peer support was reported as the most important coping strategy as was collaborating with infectious disease specialists. Conclusion. Our study affirms that there is a negative emotional impact of PJI on surgeons which can be minimized by improved peer support and working in multidisciplinary teams. Based on the surgeons’ experiences we have identified desired improvements that may facilitate the management of PJI. These may also be applicable within other surgical specialties dealing with postoperative infections, but need to be evaluated for their efficacy. Cite this article: Bone Joint J 2020;102-B(6):736–743

Aims. The aims of the study were to analyze differences in surgical and oncological outcomes, as well as quality of life (QoL) and function in patients with ankle sarcomas undergoing three forms of surgical treatment, minor or major limb salvage surgery (LSS), or amputation. Methods. A total of 69 patients with ankle sarcomas, treated between 1981 and 2017 at two tumour centres, were retrospectively reviewed (mean age at surgery: 46.3 years (SD 22.0); 31 females (45%)). Among these 69 patients 25 were analyzed prospectively (mean age at latest follow-up: 61.2 years (SD 20.7); 11 females (44%)), and assessed for mobility using the Prosthetic Limb Users Survey of Mobility (PLUS-M; for amputees only), the Toronto Extremity Salvage Score (TESS), and the University of California, Los Angeles (UCLA) Activity Score. Individual QoL was evaluated in these 25 patients using the five-level EuroQol five-dimension (EQ-5D-5L) and Fragebogen zur Lebenszufriedenheit/Questions on Life Satisfaction (FLZ). Results. Of the total number of patients in the study, 22 (32%) underwent minor LSS and 22 (32%) underwent major LSS; 25 underwent primary amputation (36%). Complications developed in 26 (38%) patients, and were more common in those with major or minor LSS in comparison to amputation (59% vs 36% vs 20%; p = 0.022). A time-dependent trend towards higher complication risk following any LSS was present (relative risk: 0.204; 95% confidence interval (CI) 0.026 to 1.614; p = 0.095). In the prospective cohort, mean TESS was higher following minor LSS in comparison to amputation (91.0 vs 67.3; p = 0.006), while there was no statistically significant difference between major LSS and amputation (81.6 vs 67.3; p = 0.099). There was no difference in mean UCLA (p = 0.334) between the three groups (p = 0.334). None of the items in FLZ or EQ-5D-5L were different between the three groups (all p > 0.05), except for FLZ item “self-relation”, being lower in amputees. Conclusion. Complications are common following LSS for ankle sarcomas. QoL is comparable between patients with LSS or amputation, despite better mobility scores for patients following minor LSS. We conclude that these results allow a decision for amputation to be made more easily in patients particularly where the principles of oncological surgery would otherwise be at risk. Cite this article: Bone Joint J 2021;103-B(3):553–561

Aims. The morphometry of the distal femur was largely studied to improve bone-implant fit in total knee arthroplasty (TKA), but little is known about the asymmetry of the posterior condyles. This study aimed to investigate the dimensions of the posterior condyles and the influence of externally rotating the femoral component on potential prosthetic overhang or under-coverage. Patients and Methods. We analysed the shape of 110 arthritic knees at the time of primary TKA using pre-operative CT scans. The height and width of each condyle were measured at the posterior femoral cut in neutral position, and in 3º and 5º of external rotation, using both central and medial referencing systems. We compared the morphological characteristics with those of 14 TKA models. Results. In the neutral position, the dimensions of the condyles were nearly equal. Externally rotating the femoral cut by 3º and 5º with ‘central referencing’ induced width asymmetry >  3 mm in 23 (21%) and 33 (30%) knees respectively, while with ‘medial referencing’ it induced width asymmetry > 3 mm in 43 (39%) and 75 (68%) knees respectively. The asymmetries induced by rotations were not associated with gender, aetiology or varus-valgus alignment. Conclusion. External rotation may amplify the asymmetry between the medial and lateral condyles, and exacerbate prosthetic overhang, particularly in the superolateral zone. ‘Central referencing’ guides result in less potential prosthetic overhang than ‘medial referencing’ guides. Cite this article: Bone Joint J 2017;99-B:894–903

Aims. This systematic review asked which patterns of complications are associated with the three reverse total shoulder arthroplasty (RTSA) prosthetic designs, as classified by Routman et al, in patients undergoing RTSA for the management of cuff tear arthropathy, massive cuff tear, osteoarthritis, and rheumatoid arthritis. The three implant design philosophies investigated were medial glenoid/medial humerus (MGMH), medial glenoid/lateral humerus (MGLH), and lateral glenoid/medial humerus (LGMH). Methods. A systematic review of the literature was performed via a search of MEDLINE and Embase. Two reviewers extracted data on complication occurrence and patient-reported outcome measures (PROMs). Meta-analysis was conducted on the reported proportion of complications, weighted by sample size, and PROMs were pooled using the reported standardized mean difference (SMD). Quality of methodology was assessed using Wylde’s non-summative four-point system. The study was registered with PROSPERO (CRD42020193041). Results. A total of 42 studies met the inclusion and exclusion criteria. Rates of scapular notching were found to be significantly higher in MGMH implants (52% (95% confidence interval (CI) 40 to 63)) compared with MGLH ((18% (95% CI 6 to 34)) and LGMH (12% (95% CI 3 to 26)). Higher rates of glenoid loosening were seen in MGMH implants (6% (95% CI 3 to 10)) than in MGLH implants (0% (95% CI 0 to 2)). However, strength of evidence for this finding was low. No significant differences were identified in any other complication, and there were no significant differences observed in PROMs between implant philosophies. Conclusion. This systematic review has found significant improvement in PROMS and low complication rates across the implant philosophies studied. Scapular notching was the only complication found definitely to have significantly higher prevalence with the MGMH implant design. Cite this article: Bone Joint J 2021;103-B(5):813–821

Aims. There is evidence that prior lumbar fusion increases the risk of dislocation and revision after total hip arthroplasty (THA). The relationship between prior lumbar fusion and the effect of femoral head diameter on THA dislocation has not been investigated. We examined the relationship between prior lumbar fusion or discectomy and the risk of dislocation or revision after THA. We also examined the effect of femoral head component diameter on the risk of dislocation or revision. Methods. Data used in this study were compiled from several Finnish national health registers, including the Finnish Arthroplasty Register (FAR) which was the primary source for prosthesis-related data. Other registers used in this study included the Finnish Health Care Register (HILMO), the Social Insurance Institutions (SII) registers, and Statistics Finland. The study was conducted as a prospective retrospective cohort study. Cox proportional hazards regression and Kaplan-Meier survival analysis were used for analysis. Results. Prior lumbar fusion surgery was associated with increased risk of prosthetic dislocation (hazard ratio (HR) = 2.393, p < 0.001) and revision (HR = 1.528, p < 0.001). Head components larger than 28 mm were associated with lower dislocation rates compared to the 28 mm head (32 mm: HR = 0.712, p < 0.001; 36 mm: HR = 0.700, p < 0.001; 38 mm: HR = 0.808, p < 0.140; and 40 mm: HR = 0.421, p < 0.001). Heads of 38 mm (HR = 1.288, p < 0.001) and 40 mm (HR = 1.367, p < 0.001) had increased risk of revision compared to the 28 mm head. Conclusion. Lumbar fusion surgery was associated with higher rate of hip prosthesis dislocation and higher risk of revision surgery. Femoral head component of 32 mm (or larger) associates with lower risk of dislocation in patients with previous lumbar fusion. Cite this article: Bone Joint J 2020;102-B(8):1003–1009

Aims. The aim of this study was to compare the surgical and quality-of-life outcomes of children with skeletal dysplasia to those in children with idiopathic early-onset scoliosis (EOS) undergoing growth-friendly management. Patients and Methods. A retrospective review of two prospective multicentre EOS databases identified 33 children with skeletal dysplasia and EOS (major curve ≥ 30°) who were treated with growth-friendly instrumentation at younger than ten years of age, had a minimum two years of postoperative follow-up, and had undergone three or more lengthening procedures. From the same registries, 33 matched controls with idiopathic EOS were identified. A total of 20 children in both groups were treated with growing rods and 13 children were treated with vertical expandable prosthetic titanium rib (VEPTR) instrumentation. Results. Mean preoperative major curves were 76° (34° to 115°) in the skeletal dysplasia group and 75° (51° to 113°) in the idiopathic group (p = 0.55), which were corrected at final follow-up to 49° (13° to 113°) and 46° (12° to 112°; p = 0.68), respectively. T1-S1 height increased by a mean of 36 mm (0 to 105) in the skeletal dysplasia group and 38 mm (7 to 104) in the idiopathic group at the index surgery (p = 0.40), and by 21 mm (1 to 68) and 46 mm (7 to 157), respectively, during the distraction period (p = 0.0085). The skeletal dysplasia group had significantly worse scores in the physical function, daily living, financial impact, and parent satisfaction preoperatively, as well as on financial impact and child satisfaction at final follow-up, than the idiopathic group (all p < 0.05). The domains of the 24-Item Early-Onset Scoliosis Questionnaire (EOSQ24) remained at the same level from preoperative to final follow-up in the skeletal dysplasia group (all p > 0.10). Conclusion. Children with skeletal dysplasia gained significantly less spinal growth during growth-friendly management of their EOS and their health-related quality of life was significantly lower both preoperatively and at final follow-up than in children with idiopathic EOS. Cite this article: Bone Joint J 2019;101-B:1563–1569

Aims

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.

Aims. Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has largely been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e. whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA. Methods. We analysed the shape of 114 arthritic knees at the time of primary TKA using the pre-operative CT scans. The aspect ratio and trapezoidicity ratio were quantified, and the post-operative prosthetic overhang was calculated. We compared the morphological characteristics with those of 12 TKA models. Results. There was significant variation in both the aspect ratio and trapezoidicity ratio between individuals. Femoral trapezoidicity was mostly due to an inward curve of the medial cortex. Overhang was correlated with the aspect ratio (with a greater chance of overhang in narrow femurs), trapezoidicity ratio (with a greater chance in trapezoidal femurs), and the tibio-femoral angle (with a greater chance in valgus knees). . Discussion. This study shows that rectangular/trapezoidal variability of the distal femur cannot be ignored. Most of the femoral components which were tested appeared to be excessively rectangular when compared with the bony contours of the distal femur. These findings suggest that the design of TKA should be more concerned with matching the trapezoidal/rectangular shape of the native femur. Take home message: The distal femur is considerably more trapezoidal than most femoral components, and therefore, care must be taken to avoid anterior prosthetic overhang in TKA. Cite this article: Bone Joint J 2016;98-B:49–57

Aims. Metaphyseal fixation during revision total knee arthroplasty (TKA) is important, but potentially difficult when using historical designs of cone. Material and manufacturing innovations have improved the size and shape of the cones which are available, and simplified the required bone preparation. In a large series, we assessed the implant survivorship, radiological results, and clinical outcomes of new porous 3D-printed titanium metaphyseal cones featuring a reamer-based system. Methods. We reviewed 142 revision TKAs in 139 patients using 202 cones (134 tibial, 68 femoral) which were undertaken between 2015 and 2016. A total of 60 involved tibial and femoral cones. Most cones (149 of 202; 74%) were used for Type 2B or 3 bone loss. The mean age of the patients was 66 years (44 to 88), and 76 (55 %) were female. The mean body mass index (BMI) was 34 kg/m. 2. (18 to 60). The patients had a mean of 2.4 (1 to 8) previous operations on the knee, and 68 (48%) had a history of prosthetic infection. The mean follow-up was 2.4 years (2 to 3.6). Results. Survivorship free of cone revision for aseptic loosening was 100% and survivorship free of any cone revision was 98%. Survivorships free of any revision and any reoperation were 90% and 83%, respectively. Five cones were revised: three for infection, one for periprosthetic fracture, and one for aseptic tibial loosening. Radiologically, three unrevised femoral cones appeared loose in the presence of hinged implants, while the remaining cones appeared stable. All cases of cone loosening occurred in patients with Type 2B or 3 defects. The mean Knee Society score (KSS) improved significantly from 50 (0 to 94) preoperatively to 87 (72 to 94) (p < 0.001). Three intraoperative fractures with cone impaction (two femoral, one tibial) healed uneventfully. Conclusion. Novel 3D-printed titanium cones, with a reamer-based system, yielded excellent early survivorship and few complications in patients with severe bone loss undergoing difficult revision TKA. The diversity of cone options, relative ease of preparation, and outcomes rivalling those of previous designs of cone support their continued use. Cite this article: Bone Joint J 2020;102-B(6 Supple A):107–115

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The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance.

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This study aimed to analyze the accuracy and errors associated with 3D-printed, patient-specific resection guides (3DP-PSRGs) used for bone tumour resection.

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Despite numerous studies focusing on periprosthetic joint infections (PJIs), there are no robust data on the risk factors and timing of metachronous infections. Metachronous PJIs are PJIs that can arise in the same or other artificial joints after a period of time, in patients who have previously had PJI.

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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.

Orthopaedic surgeons are currently faced with an overwhelming number of choices surrounding total knee arthroplasty (TKA), not only with the latest technologies and prostheses, but also fundamental decisions on alignment philosophies. From ‘mechanical’ to ‘adjusted mechanical’ to ‘restricted kinematic’ to ‘unrestricted kinematic’ — and how constitutional alignment relates to these — there is potential for ambiguity when thinking about and discussing such concepts. This annotation summarizes the various alignment strategies currently employed in TKA. It provides a clear framework and consistent language that will assist surgeons to compare confidently and contrast the concepts, while also discussing the latest opinions about alignment in TKA. Finally, it provides suggestions for applying consistent nomenclature to future research, especially as we explore the implications of 3D alignment patterns on patient outcomes.

Cite this article: Bone Joint J 2023;105-B(2):102–108.

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The aim of this study was to compare outcomes after growth-friendly treatment for early-onset scoliosis (EOS) between patients with skeletal dysplasias versus those with other syndromes.

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A higher failure rate has been reported in haematogenous periprosthetic joint infection (PJI) compared to non-haematogenous PJI. The reason for this difference is unknown. We investigated the outcome of haematogenous and non-haematogenous PJI to analyze the risk factors for failure in both groups of patients.