Prosthetic joint infection (PJI) is a devastating complication following hip and knee arthroplasty, with significant morbidity and mortality. While 24 hours of intravenous antibiotics is standard for inpatient arthroplasty, there is no consensus on postoperative antibiotic prophylaxis for outpatient procedures. This study evaluated 90-day PJI rates in patients undergoing same-day discharge primary hip and knee arthroplasty with 24 hours of perioperative oral antibiotics. A retrospective review was conducted on 1,843 patients who underwent primary total knee arthroplasty (TKA; 1,052, 57.1%), total hip arthroplasty (THA; 638, 34.7%), unicompartmental knee replacements (medial: 89, 4.8%; lateral: 5, 0.3%), isolated patellofemoral replacements (14, 0.8%), or conversion of previous hip surgeries (4, 0.2%) from 2021 to 2023 at two ambulatory surgery centers. All patients received 24 hours of perioperative oral antibiotics. Patient data were collected via chart review and the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI). The primary outcome was PJI within 90 days of surgery. The median age was 66 years, and the median BMI was 31 kg/m². PJI occurred in 5 patients (0.3%; 3 THA, 2 TKA). There were no significant differences in PJI rates based on gender, BMI, race, smoking status, diabetes, ASA class, procedure type, or surgical approach (P < 0.05). Twenty-four hours of perioperative oral antibiotics following outpatient TKA, THA, unicompartmental, and patellofemoral procedures is associated with low PJI rates. Larger, randomized prospective studies are needed to refine antibiotic protocols for outpatient arthroplasty.

Current concepts of medial unicompartmental knee replacement: part2-hot topics and further directions.

Current concepts of medial unicompartmental knee replacement: part1 history and actual indications.

Satisfactory survivorship and clinical outcomes up to 10 years after the implantation of a novel personalized metal implant for the treatment of osteochondral lesions of the knee.

MRI templating for Oxford partial knee replacement femoral component - a novel sizing method.

BackgroundIn response to rising demand, disruptions from the COVID-19 pandemic, and the need for improved cost-effectiveness, the way hip and knee replacements are being delivered is rapidly changing. Increasingly, they are being performed as day case procedures without an overnight stay in hospital. This study assessed the safety of this for a national cohort of NHS-funded procedures in England.MethodsData from the National Joint Registry, Hospital Episode Statistics, and Civil Registration of Deaths databases were linked to identify patients who underwent total hip replacement (THR) and total or unicompartmental knee replacement (TKR/UKR) in England between 2010 and 2022. Outcomes including 30-day readmissions, 90-day serious adverse events, and 1-year reoperations were compared between day case and one-day stay inpatients using adjusted flexible parametric survival models.ResultsThe study included 7485 day case and 60,747 one-day stay inpatient procedures. Day case surgery was associated with a higher risk of 30-day readmission for THR (adjusted relative risk (RR) 1.28, 95% CI 1.07 to 1.53) and TKR (RR 1.28, 95% CI 1.10 to 1.48). A learning curve was observed where the first 6-day case THRs and the first 4-day case TKRs per unit carried significantly higher readmission risk. There were no differences in 90-day serious adverse events. However, day case TKR was associated with an increased risk of reoperation within 1 year (RR 1.50, 95% CI 1.15 to 1.96; NNTH 84), most commonly manipulation under anaesthesia (MUA). No significant differences were found for UKR.ConclusionsDay case UKR appears safe. Day case THR is generally safe, and although there is a higher risk of readmission in the first six procedures at each unit, other safety outcomes are not different. However, day case TKR carries an increased risk of reoperation, mainly for MUA which is typically performed for postoperative stiffness.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12916-025-04280-y.

BackgroundLength of stay (LOS) after hip and knee replacement has decreased steadily in the modern era with enhanced recovery protocols, enabling healthcare systems to address rising surgical demand in an ageing, comorbid population. This study examines trends in LOS, patient characteristics, and their associations for NHS-funded procedures in England, covering a period that includes the COVID-19 pandemic.MethodsData from the National Joint Registry and Hospital Episode Statistics were linked to identify patients who underwent primary total hip replacement (THR) and total or unicompartmental (partial) knee replacement (TKR/UKR) in England between January 2010 and March 2022. LOS was analysed using flexible parametric models to estimate median values over time, with subsequent adjustment to examine associations between changing patient characteristics. Trends in 30-day readmission rates were also analysed.ResultsFrom 2010 to 2022, median LOS decreased from 4.26 days (95% CI 4.22 to 4.30) to 2.75 days (95% CI 2.74 to 2.77) for THR, from 4.35 days (95% CI 4.32 to 4.39) to 2.91 days (95% CI 2.90 to 2.92) for TKR, and from 3.2 days (95% CI 3.16 to 3.25) to 1.91 days (95% CI 1.89 to 1.95) for UKR. Variability also decreased. There were no increases in crude 30-day readmission rates. Trends in patient demographics showed increasing comorbidity, obesity, male sex, affluence, and use of the independent sector, all of which were associated with LOS and had the overall effect of slightly attenuating its reduction. Significant changes in patient characteristics occurred around the time of the COVID-19 pandemic but have since resumed previous trends.ConclusionsPatients in England now typically stay fewer than three days for total hip or knee replacement and under two days for partial knee replacement. Despite demographic trends towards characteristics associated with longer LOS, reductions have occurred independently of these changes, suggesting potential for further shortening. However, as these diverging trends continue, ensuring equitable access to surgery will be increasingly important.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12916-025-04294-6.

Hip and knee replacements are increasingly being performed as day-case procedures without an overnight stay in hospital. The aim of this study was to describe trends surrounding this practice for a national cohort of patients in England. The National Joint Registry and Hospital Episode Statistics were linked to identify patients who underwent NHS-funded total hip replacement (THR) and total or unicompartmental knee replacement (TKR/UKR) in England between January 2010 and March 2022. Trends in day-case surgery were described as counts and proportions of all inpatient procedures at national, regional, and local levels. Day-case patient and surgical characteristics were described and compared over time and by volume, using linear regression models, in relation to trends in inpatient procedures. A total of 1,455,842 procedures were included, of which 7,485 were day-cases: 2,420 THRs, 2,509 TKRs, and 2,556 UKRs. The rate of day-case surgery increased over time, with 52.9% of recorded day-case procedures occuring from 2019 onwards. Between 2016 and 2022, the proportion of procedures done as a day-case increased from 0.3% to 1.05% for THR, from 0.38% to 1.05% for TKR, and from 1.98% to 9.3% for UKR. Most of the increase in day-case activity occurred in NHS units. There was significant regional and local variation, with a small number of units accounting for most day-case procedures. Patients who underwent THR or TKR as a day-case were significantly younger and healthier than those who underwent these procedures as an inpatient, with a trend towards increasing selectivity over time. However, by contrast, higher-volume day-case units became slightly less selective for certain characteristics as volume increased. Although the number of major joint replacements being undertaken as a day-case has increased rapidly in England, particularly since the COVID-19 pandemic, this remains a small proportion of procedures compared with the rates in other contemporary healthcare settings.

The risk of early revision after trainee led primary unicompartmental and total knee replacement.

Background/Objectives: This study investigates the impact of Disease-Specific Care Certification (DSCC) on total medical costs associated with joint replacement surgeries in Taiwan. Methods: Using retrospective inpatient data from a regional hospital, we analyzed 660 cases of primary total knee replacement (DRG20903), total hip replacement (DRG20904), and unicompartmental knee replacement (DRG20905) classified under Taiwan’s Tw-DRG system. The dataset covered a 24-month period before certification and a 17-month period after certification, allowing for a comparison of cost changes associated with DSCC implementation. Results: While total medical costs increased slightly following certification, the differences across DRG categories were not statistically significant. However, significant increases were observed in rehabilitation costs (all DRGs), surgical costs (DRG20904 and DRG20905), anesthesia costs (DRG20904), and injection-related costs (DRG20905), indicating increased investment in standardized postoperative care. In contrast, blood transfusion and special materials costs significantly decreased in DRG20905, possibly reflecting improved care coordination and resource optimization. Additionally, the proportion of patients with prolonged hospital stays (≥11 days) declined significantly, suggesting potential efficiency gains. Conclusions: These findings imply that DSCC may facilitate better resource allocation and clinical standardization without substantially increasing overall medical expenditures, offering valuable insights for hospital administrators and policymakers operating under global budgeting systems.

Background: Successful unicompartmental knee arthroplasty (UKA) requires complete ligamentous competence, including the anterior cruciate ligament (ACL). The present study evaluated the long-term outcomes, complications, survival, and osteoarthritis (OA) progression in patients with medial femorotibial OA and ACL lesions undergoing simultaneous combined UKA and ACL reconstruction (ACLR). Methods: Patients who underwent simultaneous medial UKA and ACLR or revision ACLR from January 2004 to December 2021 were retrospectively reviewed. Inclusion criteria were a minimum follow-up period of 2 years and implantation of a cemented, fixed-bearing UKA. Outcomes were measured using the Knee Society Score (KSS), Tegner Activity Scale (TAS), University of California, Los Angeles (UCLA) Activity Score, and range of motion (ROM). Results: Thirty-four patients met the inclusion criteria. Mean follow-up was 11.7 years. Mean age was 52 years. Patients demonstrated significant improvements in KSS-C (from 52.8 ± 6.8 to 94.9 ± 7.9), KSS-F (from 58.3 ± 10.0 to 98.1 ± 4.2), TAS (from 0.7 ± 0.5 to 4.9 ± 1.1), UCLA (from 1.4 ± 0.6 to 6.6 ± 1.4), and ROM (from 109.1 ± 8.9 to 126.3 ± 6.1) (p < 0.01). Survival rate was 97.1% at 11.7 years. Lachman test results improved significantly (from 16 patients with grade II and 16 grade III to 13 grade 0 and 19 grade I, p < 0.01). No significant difference in functional outcomes was found between primary and revision ACLR groups; however, patients undergoing revision ACLR exhibited higher OA progression in the lateral compartment (p = 0.03). Conclusions: Simultaneous medial UKA and ACLR or revision ACLR led to excellent long-term outcomes, high survival rates, significant functional improvements, and minimal OA progression in the lateral compartment.

Revision of unicompartmental knee replacement can achieve equivalent outcomes to primary total knee replacement when revised for confirmed pathology.

Technology is increasingly incorporated into unicompartmental knee arthroplasty (UKA) through computer-assisted navigation (N-UKA) and robot-assisted surgery (R-UKA) to improve alignment, implant positioning, and gap balancing. Whether intraoperative technology helps achieve the minimal clinically important difference (MCID) in patient-reported outcomes (PROMs) compared to conventional UKA (C-UKA) remains unclear. This systematic review aimed to assess whether differences in PROMs between C-UKA and technology-assisted UKA reached MCID values. PubMed/MEDLINE/Cochrane Library were reviewed for studies comparing PROMs between primary C-UKA (control group) and N-UKA or R-UKA. Delta improvements were compared to established MCID values. Additional radiographic and clinical differences were assessed. The review yielded four (N=328) N-UKA and seven (N=526) R-UKA studies with C-UKA cohorts as controls. Differences in preoperative and postoperative PROMs were reported as statistically significant in three of four studies (75%) comparing N-UKA and C-UKA; however, none of the studies reported values that reached the MCID. Differences in preoperative and postoperative PROMs were reported as statistically significant in four of seven studies (57.1%) comparing R-UKA and C-UKA; however, only three of the studies (42.9%) reported values that reached the MCID. Improved radiographic outcomes for N-UKA and R-UKA were reported in 75% and 57.1% of studies, respectively. Only one study reported improved revision rates with R-UKA compared to C-UKA. Though studies may report better improvements in PROMs in N-UKA and R-UKA compared to C-UKA, these often may not achieve clinical significance. Future studies should present outcome differences in the context of validated MCID as well as other metrics such as revision rates and radiographic outliers as the impetus for technology-assisted UKA.

Introduction: Technology is increasingly incorporated into unicompartmental knee arthroplasty (UKA) through computer-assisted navigation (N-UKA) and robot-assisted surgery (R-UKA) to improve alignment, implant positioning, and gap balancing. Whether intraoperative technology helps achieve the minimal clinically important difference (MCID) in patient-reported outcomes (PROMs) compared to conventional UKA (C-UKA) remains unclear. This systematic review aimed to assess whether differences in PROMs between C-UKA and technology-assisted UKA reached MCID values. Materials and Methods: PubMed/MEDLINE/Cochrane Library were reviewed for studies comparing PROMs between primary C-UKA (control group) and N-UKA or R-UKA. Delta improvements were compared to established MCID values. Additional radiographic and clinical differences were assessed. The review yielded four (N=328) N-UKA and seven (N=526) R-UKA studies with C-UKA cohorts as controls. Results: Differences in preoperative and postoperative PROMs were reported as statistically significant in three of four studies (75%) comparing N-UKA and C-UKA; however, none of the studies reported values that reached the MCID. Differences in preoperative and postoperative PROMs were reported as statistically significant in four of seven studies (57.1%) comparing R-UKA and C-UKA; however, only three of the studies (42.9%) reported values that reached the MCID. Improved radiographic outcomes for N-UKA and R-UKA were reported in 75% and 57.1% of studies, respectively. Only one study reported improved revision rates with R-UKA compared to C-UKA. Conclusion: Though studies may report better improvements in PROMs in N-UKA and R-UKA compared to C-UKA, these often may not achieve clinical significance. Future studies should present outcome differences in the context of validated MCID as well as other metrics such as revision rates and radiographic outliers as the impetus for technology-assisted UKA.

Computer navigation and patient-specific instrumentation in unicompartmental knee replacement (UKR) improve the precision of implant positioning, but there is limited information regarding their impact on implant survival and patient-reported outcomes. We aimed to compare postoperative implant survival, Oxford Knee Score (OKS) values, health-related quality of life (measured using the EuroQol-5 Dimension 3-level version [EQ-5D-3L]), and intraoperative complications between UKRs performed using computer navigation or patient-specific instrumentation versus conventional instrumentation. Using National Joint Registry data, an observational study of patients who underwent primary UKR for osteoarthritis between 2003 and 2020 was performed. The primary analyses focused on all-cause revision, and the secondary analyses focused on differences in the OKS and EQ-5D-3L at 6 to 12 months postoperatively. To account for several covariates, weights based on propensity scores were generated. Cox proportional hazards models and generalized linear models were used to assess for differences in revision risk, and OKS and EQ-5D-3L change scores, respectively, between patient groups. Sensitivity analyses accounting for body mass index were performed. Effective sample sizes (ESSs) were computed, representing the statistical power comparable with that of an unweighted sample. Compared with conventional instrumentation, the hazard ratio (HR) for all-cause revision was 1.126 (95% confidence interval [CI], 0.909 to 1.395; p = 0.277; ESS, 4,273) with computer navigation and 0.805 (95% CI, 0.442 to 1.467; p = 0.478; ESS, 1,199) with patient-specific instrumentation. No difference was found in the change in OKS between the groups (-1.287; 95% CI, -2.851 to 0.278; p = 0.107; ESS, 470), although improvement in the EQ-5D-3L scores was relatively lower for computer-navigated UKR compared with conventional instrumentation (-0.049, 95% CI, -0.093 to -0.005; p = 0.028; ESS, 455). However, sensitivity analyses demonstrated that computer navigation was associated with an increased risk of all-cause revision (HR, 1.446; 95% CI, 1.102 to 1.898; p = 0.008; ESS, 3,011) and relatively smaller improvements in the OKS (-2.845; 95% CI, -5.006 to -0.684; p = 0.010; ESS, 272) and EQ-5D-3L scores (-0.087; 95% CI, -0.145 to -0.030; p = 0.003; ESS, 286). There were no differences in intraoperative complications (p = 0.073). This study found no clinically meaningful differences in patient-reported outcomes following computer-navigated UKR. Although likely underpowered, the primary analyses showed no difference in implant survival. While a sensitivity analysis suggested that computer navigation could worsen implant survival, this analysis had a smaller sample size. These findings highlight potential signals that warrant further investigation. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Abstract Aim This project aims to identify factors contributing to delays in early mobilisation among patients undergoing lower limb arthroplasty. Understanding these barriers is essential for improving patient outcomes, especially with the trend towards sameday discharge. Method A retrospective review was conducted for 22 patients who underwent joint replacement between 1st and 12th February 2024. Clinical records were reviewed for demographics and causes of mobilisation and discharge delays. Results The mean patient age was 70 (range 52–90); 82% were female and 18% male, with 13 total knee, 7 total hip, and 2 uni-compartmental knee replacements. Initial physiotherapy occurred, on average, 21.3 hours post-surgery, with no same day reviews. Average bed-to-chair time was 21 hours, and bed-to-walking time was 24.3 hours. Delays in discharge were attributed to surgical reasons in two patients (9%) and medical reasons in one (4%). The average hospital stay was 5.3 days (range 3–12). Mobilisation delays were primarily due to limited inter-team communication and lack of prioritisation for early mobilisation (73%) and late surgeries (27%). Conclusions Poor communication among surgical, nursing, and physiotherapy teams was the main barrier to early mobilisation. Clear postoperative instructions and coordinated team efforts could reduce delays and support faster recovery.

This study examines the climate impact of two surgical treatments for knee osteoarthritis, unicompartmental knee replacement (UKR) and high tibial osteotomy (HTO), also comparing conventional manufacturing (CM) with additive manufacturing (AM) for HTO. Factors beyond the implants themselves are considered that depend on the manufacturing method, such as surgical instruments and guides (jig), sterilisation, transport and anesthesia using data obtained first hand from manufacturers and a hospital. The relevance of the comparative results are maximised beyond a specific manufacturer's product by including uncertainty in the foreground and background life cycle inventories to represent uncertainty and variability of process characteristics, materials, and geographical location. The analysis is carried out in Brightway 2 using Ecoinvent inventory data and impacts are calculated across 18 mid-point categories. To consider possible improvement to the environmental impact of the surgical interventions, alternative electricity and surgical guide (jig) material scenarios are considered. The climate change impact of UKR, 37.9 (36.8-38.9) kg CO , is highly significantly greater than that of the CM HTO, 10.7 (10.0-11.4) kg CO , and AM HTO, 13.4 (13.0-13.7) kg CO . The custom single-use surgical jig of the AM HTO and the use of potentially higher-carbon electricity leads to the AM HTO having an impact 1.25 (1.17-1.34) times higher than the CM HTO. But when low-carbon electricity is used and the surgical guide is made of stainless steel, this reduces to 0.78 (0.73-0.84). Initial screening of other lifecycle impact categories shows similar trends in most cases. This study concludes that HTO has highly significantly lower climate change impact than UKR. AM HTO has the potential to further reduce the climate impact compared to CM HTO given low-carbon energy supply and further improvements in material choice and design optimisation. Challenges include limited availability in design skill-set for optimisation and higher cost for healthcare providers compared to CM HTO, although still lower than the cost of UKR. Our study highlights policy implications: along with being a solution for early treatment and yielding improved correction accuracy compared to CM HTO, personalised AM HTO also offers environmental benefits if designed and manufactured well. The online version contains supplementary material available at 10.1007/s11367-025-02473-4.

The Radiographic Decision Aid Does Not Work in High-BMI Patients for Unicompartmental Knee Replacement: A Retrospective Matched-Control Study

Tibial periprosthetic fracture (TPF) is a severe complication of cementless Oxford Unicompartmental Knee Replacement (OUKR) with patient risk factors including small tibial size and tibia vara with an overhanging medial tibial condyle. Surgical factors also influence fracture but remain poorly defined. This finite element (FE) analysis study identified surgical risk factors for TPF after OUKR and determined the optimal tibial component positioning to minimise fracture risk. Knees in two very high-risk, small, bilateral OUKR patients who had a TPF in one knee and a good result in the other were studied with FE analysis. Each patient's unfractured tibia was used as a comparator to study surgical factors. The tibial geometries were segmented from the pre-operative CT scans and FE models were built with the tibial components implanted in their post-operative positions. The resections in the fractured and unfractured tibias were compared regarding their mediolateral position, distal-proximal position, internal-external rotation and varus-valgus orientation. Models of the TPF tibial resections in the contralateral sides were also built in both patients. The risk of TPF was assessed by examining the magnitude and location of the highest maximum principal stress. In both patients, large differences were found in the position and orientation of the tibial components in the fractured and unfractured tibias with the components in the fractured tibias placed more medially and distally. Suboptimal saw cuts resulted in poor positioning of the tibial components and created very high local stresses in the bone, particularly anteriorly (157MPa and 702MPa in the fractured side vs. 49MPa and 63MPa in the unfractured side in patient 1 and 2 respectively), causing fractures. In small patients with marked tibia vara the surgery is unforgiving. To avoid fracture, the horizontal cut should be conservative, aiming for a 3 bearing, the vertical cut should abut the apex of the medial tibial spine, and extreme internal or external rotation should be avoided. The component should be aligned with the posterior cortex and should not overhang anteriorly. In addition, contrary to current recommendations, the tibial component should be placed in varus (about 5°).

PurposeTo investigate the relationship between coronal plane changes after mobile‐ and fixed‐bearing (MB and FB) unicompartmental knee replacement (UKR) and clinical outcomes while also comparing revision rates and joint awareness between the two surgical modalities.MethodsPatients who operated between 2014 and 2017 with a UKR (FB or MB) were eligible for inclusion. Inclusion criteria were a minimum follow‐up of 5 years, presence of clinical outcome scores, Forgotten Joint Scores and radiological data (joint obliquity angles, tibial component alignment, angle between the medial and lateral joint lines, change in overall knee alignment, change in the medial proximal tibial angle). Outcome variables were compared between the MB and FB UKRs, and correlation analyses were performed to assess the effect of radiological changes on clinical and awareness scores. Two separate researchers performed all radiological measurements on direct radiographs.ResultsOut of 229 patients, 197 were eligible for inclusion. Basic demographic data (mean age, sex, body mass index and follow‐up time) were comparable between the FB and MB groups. There were more revisions in the mobile bearing group (6.5% vs. 12.5%), though the results did not reach statistical significance. Clinical outcomes and joint awareness were similar in the two groups. Overall, the change in joint line obliquity or alignment was comparable between the groups.ConclusionsClinical outcomes and joint awareness scores are similar in both fixed and mobile‐bearing UKRs. Revision is more frequent, though not statistically significant, following an MB UKR. Overall, change in knee alignment and medio‐lateral joint lines is similarly well tolerated in both implant modalities.Level of EvidenceLevel III.