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

Osteoarthritis (OA) is a highly prevalent and disabling disease with an unmet therapeutic need. The characteristic cartilage loss and alteration of other joint structures result from a complex interaction of multiple risk factors, with mechanical overload consistently playing a central role. This overload generates an inflammatory response in the cartilage due to the activation of the innate immune response in chondrocytes, which occurs through various cellular mechanisms. Moreover, risk factors associated with obesity, being overweight, and metabolic syndrome enhance the inflammatory response both locally and systemically. OA chondrocytes, the only cells present in articular cartilage, are therefore inflamed and initiate an anabolic process in an attempt to repair the damaged tissue, which ultimately results in an aberrant and dysfunctional process. Under these circumstances, where the cartilage continues to be subjected to chronic mechanical stress, proposing a treatment that stimulates the chondrocytes’ anabolic response to restore tissue structure does not appear to be a therapeutic target with a high likelihood of success. In fact, anabolic drugs proposed for the treatment of OA have yet to demonstrate efficacy. By contrast, multiple therapeutic strategies focused on pharmacologically managing the inflammatory component, both at the joint and systemic levels, have shown promise. Therefore, prioritizing the control of chronic innate pro-inflammatory pathways presents the most viable and promising therapeutic strategy for the effective management of OA. As research continues, this approach may offer the best opportunity to alleviate the burden of this incapacitating disease.

Cite this article: Bone Joint Res 2025;14(3):199–207.

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.

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. Methods. This study included 217 patients (mean age 69.7 years (SD 8.7), 116 female (53%)) who completed questionnaires that included the EuroQol five-dimension questionnaire (EQ-5D) and EuroQol-visual analogue scale (EQ-VAS), Oxford Knee Score (OKS), and wellbeing assessments at six and 12 months after being listed for surgery. Analgesia use at 12 months was also recorded. CKP was defined using the OKS pain score (PS) of ≤ 14 points at 12 months. Results. At 12 months, 169 patients (77.9%) had CKP. Compared with those without CKP, those with CKP had clinically meaningfully worse HRQoL and knee-specific health at 12 months and were more likely to have a health state worse than death (odds ratio (OR) 29.7, 95% CI 4.0 to 220.2; p < 0.001). The CKP group were more likely to use weak (OR 3.03, 95% CI 1.65 to 7.96; p = 0.001) and strong (OR 11.8, 95% CI 1.58 to 88.88; p = 0.001) opioids for analgesia. The CKP group had worse overall wellbeing with significantly (p < 0.001) lower satisfaction with life, life being worthwhile and happiness, and increased anxiety. The CKP group had a significant (p < 0.001) deterioration in their OKS, OKS-PS, EQ-5D, and EQ-VAS from six to 12 months, which was not observed in the group without CKP. A worse OKS-PS at six months was independently associated with an increased risk of CKP, and a threshold value of < 13 (sensitivity 91.7%, specificity 94.7%) was an excellent discriminator (area under the curve 96.9, 95% CI 94.2 to 99.6; p < 0.001). Conclusion. Four in five patients had CKP after waiting 12 months, which was associated with deteriorations in HRQoL and knee health, worse wellbeing, and increased opioid analgesia use. The OKS-PS at six months could be used to identify patients at risk of CKP after 12 months of waiting. Cite this article: Bone Jt Open 2025;6(3):237–245

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

Aims

To examine how eukaryotic translation initiation factor 5A (eIF5A) regulates osteoarthritis (OA) during mechanical overload and the specific mechanism.

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).

Aims. Control of acute pain following knee arthroplasty (KA) with a perioperative peripheral nerve block (PNB) may improve functional outcomes and reduce the risk of chronic postoperative knee pain (CPKP). The aims of this study were to assess whether a PNB influences patient-reported outcomes and risk of CPKP at one year following KA. Methods. A retrospective study was conducted over a two-year period and included 3,338 patients who underwent KA, of whom 1,434 (43.0%) had a lower limb PNB. A total of 2,588 patients (77.6%) completed and returned their one-year follow-up questionnaire. The Oxford Knee Score (OKS) and pain component (OKS-PS), EuroQol five-dimension questionnaire (EQ-5D), and EQ-visual analogue scale (VAS) were collected preoperatively and at one year postoperatively. Patient satisfaction was also recorded at one year. The OKS-PS was used to define CPKP at one year. Results. The PNB group were younger (mean difference (MD) 0.7 years, 95% CI 0.0 to 1.3; p = 0.039), had a worse OKS (MD 0.7, 95% CI 0.1 to 1.3; p = 0.027), and were more likely to have had a spinal anaesthesia relative to a general anaesthetic (odds ratio 4.2, 95% CI 3.23 to 5.45; p < 0.001). When adjusting for confounding factors, patients in the PNB group had a significantly reduced improvement in their OKS (MD -0.9, 95% CI -1.6 to -0.1; p = 0.022), which may not be clinically meaningful. There were no significant differences in the OKS-PS (p = 0.068), EQ-5D (p = 0.313), or EQ-VAS (0.855) between the groups when adjusting for confounding factors. When adjusting for confounding factors using binary regression analysis, there were no differences in patient satisfaction (p = 0.132) or in the risk of CPKP (p = 0.794) according to PNB group. Conclusion. PNBs were independently associated with worse knee-specific outcomes, but whether these are clinically meaningful is not clear, as the difference was less than the minimal clinically important difference. Furthermore, PNBs were not independently associated with differences in health-related quality of life, patient satisfaction, or risk of CPKP. Cite this article: Bone Jt Open 2025;6(2):147–154

The February 2025 Sports Roundup³⁶⁰ looks at: Long-term outcomes of focal cartilage lesions of the knee; Comparison of early and delayed multiligament knee reconstruction; Platelet-rich plasma does not improve recovery after partial meniscectomy; Patient height and sex predict semitendinosus autograft diameter.

The February 2025 Hip & Pelvis Roundup. 360. 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 Roundup. 360. 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

To evaluate the concurrent use of vancomycin and ε-aminocaproic acid (EACA) in primary total hip arthroplasty (THA).

Aims. Over time, the locking mechanism of Modular Universal Tumour and Revision System (MUTARS) knee arthroplasties changed from polyethylene (PE) to polyether-ether-ketone Optima (PEEK) and metal-on-metal (MoM) in an attempt to reduce the risk of mechanical failure. In this study, we aimed to assess the cumulative incidence of locking mechanism revision for symptomatic instability by type of material, and assess potential associated risk factors. Methods. The MUTARS Orthopaedic Registry Europe was used for a retrospective review of 316 patients (54% male (n = 170), median age 44 years (IQR 23 to 61)) who underwent a MUTARS knee arthroplasty for oncological indications between December 1995 and January 2023. The minimum follow-up was 12 months, and the median follow-up was 7.9 years (IQR 3.3 to 13.0). A competing risk model was used to estimate the cumulative incidence of first locking mechanism revision with death and revision for any other reason as competing events. Possible risk factors were assessed employing a univariate cause-specific hazards regression model. Results. Symptomatic instability of the hinge or locking mechanism due to wear (n = 20) or breakage (n = 14) occurred in 34 patients (11%): 9% of PE (n = 4/45), 20% of PEEK (n = 9/44), and 9% of MoM locking mechanisms (n = 21/227). The cumulative incidences of revision for instability due to wear or locking mechanism breakage at two, five, and ten years were 0%, 5% (95% CI 1 to 15), and 5% (95% CI 1 to 15) for PE, 5% (95% CI 1 to 14), 14% (95% CI 5 to 26), and 16% (95% CI 7 to 29) for PEEK, and 0%, 3% (95% CI 1 to 6), and 10% (95% CI 5 to 16) for MoM. With PE as the reference category, the cause-specific hazard ratio for PEEK and MoM were 3.6 (95% CI 1.1 to 11.9; p = 0.036) and 3.2 (95% CI 1.1 to 9.5; p = 0.043), respectively. Age, BMI, resection length, and extra-articular resections were not associated with the time to locking mechanism revision. Conclusion. Alterations in prosthetic materials have not decreased the revision risk for locking mechanism failure. Besides locking mechanism material, no other patient- or prosthesis-related risk factors for locking mechanism failure were identified. Improvement of the locking mechanism is warranted since revision exposes patients to the risk of serious secondary complications. Cite this article: Bone Joint J 2025;107-B(2):239–245

Aims. This study was performed to investigate the association between the acetabular morphology and the joint space narrowing rate (JSNR) in the non-arthritic hip. Methods. We retrospectively reviewed standing whole-leg radiographs of patients who underwent knee arthroplasty from February 2012 to March 2020 at our institute. Patients with a history of hip surgery, Kellgren-Lawrence grade ≥ II hip osteoarthritis, or rheumatoid arthritis were excluded. The hip JSNR was measured, and the normalized JSNR (nJSNR) was calculated by calibrating the joint space width with the size of the femoral head in 395 patients (790 hips) with a mean age of 73.7 years (SD 8.6). The effects of the lateral centre-edge angle (CEA) and acetabular roof obliquity (ARO) in the standing and supine positions were examined using a multivariate regression model. Results. The mean JSNR and nJSNR were 0.115 mm/year (SD 0.181) and 2.451 mm/year (SD 3.956), respectively. Multivariate regressions showed that older age was associated with a larger nJSNR (p = 0.010, standardized coefficient (SC) 0.096). The quadratic curve approximation showed that the joint space narrowing was smallest when the CEA was approximately 31.9°. This optimal CEA was the same in the standing and supine positions. Multivariate regressions were separately performed for joints with a CEA of < 31.9° and > 31.9°. When the CEA was < 31.9°, a smaller CEA was associated with a larger nJSNR (p < 0.001, SC 0.282). When the CEA was > 31.9°, a larger CEA was associated with a larger nJSNR (p = 0.012, SC 0.152). The ARO was not associated with the nJSNR. Conclusion. Both insufficient coverage and over-coverage of the acetabulum over the femoral head were associated with increased joint space narrowing in hips that were non-arthritic at baseline. The effects of insufficient coverage were stronger than those of overcoverage. Cite this article: Bone Jt Open 2025;6(1):93–102