Aims. Periprosthetic joint infections (PJIs) pose significant challenges to patients and healthcare systems worldwide. The aim of this study was to estimate the health-economic burden of reimbursement payment in Europe for PJIs following primary hip and knee arthroplasty. Methods. The calculation was based on health-economic modelling using data on primary hip and knee arthroplasties for the year 2019 from the Statistical Office of the European Union (Eurostat) and published infection rates to estimate the total number of hip and knee PJIs in 30 European countries. Revision procedures were stratified into: 1) debridement, antibiotics, and implant retention (DAIR); 2) one-stage exchange; and 3) two-stage revision procedures. The cases were then multiplied by the respective healthcare system reimbursement payments. Payment data were acquired from a survey of 13 countries (Austria, Croatia, France, Germany, Italy, Lithuania, Netherlands, Norway, Portugal, Slovenia, Switzerland, Turkey, and the UK) and extrapolated for the remaining countries. Results. In 2019, a total of 2,048,778 primary total joint replacements were performed (total hip arthroplasty (THA) = 1,147,316 and total knee arthroplasty (TKA) = 901,462), with an estimated 20,416 cases of PJIs (11,131 hip and 9,285 knee) in Europe. This results in an estimated total reimbursement burden of €346,262,026 for European healthcare systems. The breakdown for hip PJI reimbursement was €197,230,953 (€9,751,962 for DAIR procedures, €45,135,894 for one-stage revisions, and €142,343,097 for two-stage revisions). For knee PJIs, the analysis yielded a total reimbursement of €149,031,073 (€9,335,075 for DAIR procedures, €48,058,479 for one-stage revisions, and €91,637,518 for two-stage revisions). Conclusion. This is the first study to evaluate the health-economic burden of PJIs in Europe, revealing a substantial impact on healthcare systems with an estimated case load of 20,414 cases and overall reimbursement of €346,262,026 for primary THAs and TKAs performed in 2019. Cite this article: Bone Jt Open 2025;6(3):298–311

Aims

The primary objective of this study was to compare short-term implant survival between cemented and cementless fixation for the mobile-bearing Oxford medial unicompartmental knee arthroplasty (UKA) across various age groups. The secondary objectives were to compare modes of failure and to evaluate patient-reported outcomes.

Aims. The use of patient-reported outcome measures (PROMs) to assess the outcome after total knee (TKA) and total hip arthroplasty (THA) is increasing, with associated regulatory mandates. However, the robustness and clinical relevance of long-term data are often questionable. It is important to determine whether using long-term PROMs data justify the resources, costs, and difficulties associated with their collection. The aim of this study was to assess studies involving TKA and THA to determine which PROMs are most commonly reported, how complete PROMs data are at ≥ five years postoperatively, and the extent to which the scores change between early and long-term follow-up. Methods. We conducted a systematic review of the literature. Randomized controlled trials (RCTs) with sufficient reporting of PROMs were included. The mean difference in scores from the preoperative condition to early follow-up times (between one and two years), and from early to final follow-up, were calculated. The mean rates of change in the scores were calculated from representative studies. Meta-analyses were also performed on the most frequently reported PROMs. Results. A total of 24 studies were assessed. The most frequently reported PROMs were the Oxford Knee Score (OKS) for TKA and the University of California, Los Angeles activity scale for THA. The mean rate of follow-up based on the number of patients available at final follow-up was 70.5% (39.2% to 91.0%) for knees and 82.1% (63.2% to 92.3%) for hips. The actual rates of collection of PROM scores were lower. For TKA, the mean OKS, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and transformed WOMAC changes were -16.3 (95% CI -17.5 to -15.2), 23.2 (95% CI 17.2 to 29.2), and -29.7 (95% CI -32.4 to -27.0) points for short-term follow-up. These decreased to 1.3 (95% CI -0.8 to 3.3), -3.4 (95% CI -7.0 to 0.3), and 4.7 (95% CI -1.5 to 10.9) points for the remaining follow-up. A similar meta-analysis was not possible for studies involving THA. We commonly observed that the scores plateaued after between one and two years, and that there was little or no change beyond this time. Conclusion. The long-term PROMs for TKA and THA beyond one or two years are often incomplete and lose sensitivity at this time. Given the considerable resources, costs, and challenges associated with the collection of these scores, their clinical value is questionable. Therefore, consideration should be given to abandoning the requirement for the collection of long-term PROMs in favour of more robust and reliable measures of success that offer more clinical relevance and use. Cite this article: Bone Joint J 2025;107-B(3):296–307

Aims

Unicompartmental knee arthroplasty (UKA) is one option in the treatment of isolated unicompartmental advanced osteoarthritis (OA). While long-term results exist for medial mobile-bearing (MB) UKA, evidence regarding lateral MB-UKA is still limited. The Oxford Domed Lateral (ODL) implant aims to reduce the bearing dislocation rate in lateral MB-UKA through enhanced bearing entrapment. However, the long-term performance of this implant remains unclear. This study evaluated the long-term survival and clinical outcomes of the ODL in a non-designer centre.

Aims

To assess whether chronic knee pain (CKP) influenced health-related quality of life (HRQoL), knee-specific health, wellbeing, and use of opioid analgesia, and identify variables associated with CKP in patients awaiting knee arthroplasty.

Aims. The aim of this study was to examine the indications for further surgery and the characteristics of the patients within one year of medial unicompartmental knee arthroplasty (mUKA), providing an assessment of everyday clinical practice and outcomes in a high-volume country. Methods. All mUKAs which were performed between 1 April 2020 and 31 March 2021 and underwent further surgery within one year, from the Danish Knee Arthroplasty Registry (DKAR), were included. For primary procedures and reoperations, we received data on the characteristics of the patients, the indications for surgery, the type of procedure, and the sizes of the components individually, from each Danish private and public arthroplasty centre. All subsequent reoperations were recorded regardless of the time since the initial procedure. Results. A total of 2,431 primary mUKAs in 2,303 patients were reported to the DKAR during the study period and 55 patients (55 mUKAs; 2.3%; (95% CI 1.7 to 3.0)) underwent further surgery within one year. The most frequent indications for reoperation were periprosthetic fracture (n = 16; 0.7% (95% CI 0.4 to 1.1)), periprosthetic joint infection (PJI) (n = 13; 0.5% (95% CI 0.3 to 0.9)), and bearing dislocation (n = 9; 0.4% (95% CI 0.2 to 0.7)). Six periprosthetic fractures were treated with internal fixation, but five of these patients later underwent revision to a total knee arthroplasty (TKA). Ten PJIs were treated with debridement, antibiotics, and implant retention (DAIR). Due to persistent infection, four of these patients later underwent revision to a TKA. All nine bearing dislocations were treated with exchange of the liner, and seven occurred in patients who, based on their sex and height, probably had undersized femoral components. Conclusion. Reoperations are rare following mUKA in a high-volume country. The most frequent indications for further surgery were periprosthetic fracture, PJI, and bearing dislocation. Using internal fixation to treat periprosthetic fractures after mUKA gives poor results. Whether DAIR is an appropriate form of treatment for PJI in mUKAs, and how to ensure the effective eradication of infection in these patients, remains uncertain. Undersizing the femoral component might increase the risk of bearing dislocation. Cite this article: Bone Joint J 2025;107-B(3):314–321

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Fracture-related infections (FRIs) are a major concern for patients and healthcare systems, yet their impact on mental health has been largely overlooked. This study aimed to assess the longitudinal impact of FRI on patients’ quality of life.

Aims

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.

Aims. 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). Methods. The total versus robotic-assisted unicompartmental knee arthroplasty (TRAKER) trial is a patient- and assessor-blinded, pragmatic parallel two-arm randomized superiority trial of adults undergoing elective primary knee arthroplasty for primary medial compartment OA at a single NHS hospital (ClinicalTrials.gov NCT05290818). Participants will be randomly allocated on a 1:2 basis to either raUKA or mTKA, respectively. The primary analysis will compare the Oxford Knee Score (OKS) six months after surgery. Secondary outcomes measured at three, six, and 12 months include the OKS, Forgotten Joint Score, patient expectations, EuroQol five-dimension questionnaire (EQ-5D), and EQ-visual analogue scale (EQ-VAS), patient satisfaction, range of motion, postoperative complications, need for further surgery, resource use, and financial costs. Cost-effectiveness will be measured over a ten-year time span. A total of 159 patients will be randomized (n = 53 raUKA vs n = 106 mTKA) to obtain 80% power to detect a five-point difference in OKS between the groups six months after surgery. Conclusion. The trial findings will provide evidence about the clinical and cost-effectiveness of raUKA compared to mTKA in patients with isolated medial compartment OA. This will inform future National Institute for Health and Care Excellence guidelines on primary knee arthroplasty in the UK. Cite this article: Bone Jt Open 2025;6(2):164–177

The February 2025 Hip & Pelvis Roundup³⁶⁰ looks at: Postoperative periprosthetic femoral fractures after hip arthroplasty: quantifying the other half of the picture; Hip arthroscopy in patients with borderline dysplasia: how do we know when it will not work?; The morbidly obese patient remains a challenge for arthroplasty surgeons; Unexpected positive cultures in aseptic revision hip and knee arthroplasty: does it make a difference?; Failed spinal anaesthesia in hip and knee arthroplasty surgery; Clinical failure of femoral neck fracture is associated with varus necks; Navigating the angles: how variations in femoral and acetabular versions influence hip pain and treatment; High-tech or hands-on? Similar outcomes in direct anterior total hip arthroplasty.

The February 2025 Knee Roundup³⁶⁰ looks at: Once-weekly semaglutide in patients with obesity and knee osteoarthritis; How many patients should have a unicompartmental knee arthroplasty?; Staged revision of the infected knee arthroplasty and endoprosthesis; The metal allergy argument and knee arthroplasty; Is kinematic alignment all it’s cracked up to be?; Is bone-patella-bone the gold standard for revision?; Blood flow restriction and the dissatisfied knee arthroplasty.

Aims

The aim of this study was to assess the incidence of reinfection in patients after two-stage revision of an infected megaprosthesis (MPR) implanted after resection of a bone tumour.

Aims. Radiostereometric analysis (RSA) is considered the gold standard for in vivo migration analysis, but CT-based alternatives show comparable results in the shoulder and hip. We have previously validated a CT-based migration analysis method (CTMA) in a knee phantom compared to RSA. In this study, we validated the method in patients undergoing total knee arthroplasty (TKA). Our primary outcome measure was the difference in maximum total point motion (MTPM) between the differing methods. Methods. A total of 31 patients were prospectively studied having undergone an uncemented medial pivot knee TKA. Migrations were measured up to 12 months with marker-based and model-based RSA, and CT-RSA. Results. Mean precision data for MTPM were 0.27 mm (SD 0.09) for marker-based RSA, 0.37 mm (SD 0.26) for model-based RSA, and 0.25 mm (SD 0.11) for CTMA. CTMA was as precise as both RSA methods (p = 0.845 and p = 0.156). At three months, MTPM showed a mean of 0.66 mm (95% CI 0.52 to 0.81) for marker-based RSA, 0.79 (95% CI 0.64 to 0.94) for model-based RSA, and 0.59 (95% CI 0.47 to 0.72) for CTMA. There was no difference between CTMA and marker-based RSA (p = 0.400), but CTMA showed lower migration than model-based RSA (p = 0.019). At 12 months, MTPM was 1.03 (95% CI 0.79 to 1.26) for marker-based RSA, 1.02 (95% CI 0.79 to 1.25) for model-based RSA, and 0.71 (95% CI 0.48 to 0.94) for CTMA. MTPM for CTMA was lower than both RSA methods (p < 0.001). Differences between migration increased between the methods from three to 12 months. Mean effective radiation doses per examination were 0.016 mSv (RSA) and 0.069 mSv (CT). Imaging time for performing RSA radiographs was 17 minutes 26 seconds (SD 7 mins 9 sec) and 4 minutes 24 seconds (SD 2 mins 3 sec) for CT. Conclusion. No difference in precision was found between CTMA and marker- or model-based RSA, but CTMA shows lower migration values of the tibial component at 12 months. CTMA can be used with low effective radiation doses, and CT image acquisition is faster to perform than RSA methods and may be suitable for use in ordinary clinical settings. Cite this article: Bone Joint J 2025;107-B(2):173–180

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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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We estimated the prevalence of people living with at least one hip, knee, or shoulder arthroplasty in the Netherlands.