BACKGROUND:Uncemented total knee arthroplasty (TKA) components were developed to improve fixation relative to cemented implants. While uncemented femoral components have yielded favorable results, outcomes for earlier uncemented tibial and patellar designs have been inconsistent. Contemporary trabecular-metal implants aim to enhance biological fixation by optimizing osseointegration, yet randomized data comparing fully uncemented constructs, including the patella, are limited. We conducted a prospective, single-blinded randomized controlled trial comparing 5-year radiological, clinical, and patient-reported outcomes of fully cemented and fully uncemented trabecular-metal TKA with patella resurfacing. METHODS:Between 2017 and 2020, 316 knees (280 patients) were randomized 1:1 to fully cemented (n = 158) or fully uncemented (n = 158) TKA with patella resurfacing. There were 15 patients randomized to the uncemented group who required cementation of at least one component. The primary outcome was implant fixation at five years, assessed on standardized radiographs for progressive and nonprogressive radiolucent lines. The secondary outcomes included revisions, other reoperations, and patient-reported outcome measures at five years. Risk ratios, t-tests, and Chi-square tests were performed using a modified intention-to-treat approach. RESULTS:Follow-up was 97% at five years. Uncemented TKA had fewer nonprogressive radiolucent lines than cemented TKA (two versus 27 cases, relative risk [RR]: 0.50, 95% confidence interval [CI]: 0.42 to 0.59, P < 0.001). There was one progressive radiolucency that occurred in the cemented group. There were no differences between the groups for revisions (one cemented versus two uncemented, RR 1.52, CI: 0.31 to 7.56, P = 0.55), other reoperations (10 cemented versus eight uncemented, RR: 0.90, CI 0.59 to 1.39, P = 0.66), or patient-reported outcome measures (Oxford Knee Score, EuroQol-5 Dimensions, International Knee Society Score, Pain Visual Analog Scale, Forgotten Joint Score, and Satisfaction). CONCLUSIONS:At five years, fully uncemented TKA using trabecular metal with patella resurfacing demonstrated equivalent clinical and patient-reported outcomes and similar revision/reoperation rates to fully cemented TKA, with fewer nonprogressive radiolucent lines. Longer-term follow-up is required to determine whether radiographic differences affect implant survivorship and longevity overall.

BACKGROUND:Changes to native coronal plane alignment of the knee (CPAK) phenotypes following total knee arthroplasty may influence outcomes, particularly with mechanical alignment (MA). This relationship has not been evaluated with functional alignment (FA). This study compared the magnitude of coronal alignment change between MA and FA and whether this influenced patient-reported outcomes. METHODS:This substudy analyzed data from a prospective, single-center, single-blinded randomized controlled trial involving 236 patients (119 FA and 117 MA). Long-leg radiographs were used to calculate the arithmetic hip-knee-ankle angle (aHKA), joint line obliquity (JLO), and CPAK phenotype preoperatively and postoperatively. Alignment change was assessed using absolute differences (change in aHKA, change in JLO), and a dose-response analysis was conducted. Clinical outcomes included the Forgotten Joint Score (FJS) and Oxford Knee Score at 1- and 2-yeas follow-up. RESULTS:The FA resulted in smaller changes in alignment compared to MA (Δ aHKA P = 0.01; change in JLO P = 0.01) and more frequent restoration of the preoperative CPAK phenotype (42.9 versus 10.3%, P = 0.01). In the MA group, restoration of the CPAK phenotype was associated with significantly higher FJS, whereas no such relationship was observed in the FA group. A dose-response relationship was identified in the MA group: greater changes in JLO were negatively correlated with FJS. This correlation was not seen with FA. CONCLUSIONS:Functional alignment more closely preserved native coronal alignment and restored CPAK phenotypes compared to MA. In MA cases, larger deviations from the native JLO and CPAK phenotypes were associated with poorer patient-reported outcomes. These findings suggest anticipating alignment changes may support optimal strategy selection in total knee arthroplasty. LEVEL OF EVIDENCE:Level I prospective randomized study.

Background:Psychological factors have been reported to influence postoperative clinical outcomes following knee arthroplasties. The present study aimed to examine the association between preoperative central sensitization and pain catastrophizing and postoperative outcomes in patients undergoing unicompartmental knee arthroplasty (UKA) vs total knee arthroplasty (TKA). Methods:This prospective cohort study included 353 patients divided into 2 groups according to the surgical procedure: UKA (n = 72) and TKA (n = 281). The Central Sensitization Inventory (CSI) and Pain Catastrophizing Scale (PCS) questionnaires were administered preoperatively, and patient-reported outcome measures (PROMs) were evaluated according to the subscales of the Knee Injury and Osteoarthritis Outcome Score 1 year postoperatively. Preoperative CSI and PCS scores were compared between patients undergoing UKA vs TKA, and the correlations with PROMs were analyzed. Results:The mean (± standard deviation) preoperative CSI and PCS scores were 21.4 ± 10.5 and 27.3 ± 10.8 for the UKA group, and 22.6 ± 14.1 and 26.2 ± 12.9 for the TKA group; however, the differences in these scores between the groups were not statistically significant (P = .51 and P = .53, respectively). CSI and PCS scores exhibited no correlation with any postoperative subscale in PROMs (all subscales in Knee Injury and Osteoarthritis Outcome Score) in UKA. However, CSI and PCS scores exhibited negative correlations with all subscales in PROMs in TKA. Conclusions:There were no statistical differences in preoperative central sensitization and pain catastrophizing between patients who underwent UKA vs TKA. However, these psychological factors negatively affected postoperative PROMs in patients who underwent TKA, whereas, they were not found to significantly affect postoperative PROMs in the UKA group; however, this finding may reflect limited sample size rather than a true absence of effect.

BACKGROUND:Understanding the causative microorganisms and initiating appropriate empirical antibiotics early are important in the management of knee periprosthetic joint infections (PJIs). The aim of this study was to identify trends in PJI microorganisms and antibiotic resistance profiles over 24 years to guide empirical antibiotic selection. METHODS:This study included 487 first-episode PJIs identified between 2000 and 2023 following primary total knee arthroplasty (TKA) at 3 large tertiary hospitals. PJIs were classified using the Tsukayama classification, which is based on the timing from the primary TKA and the source of infection. Multivariable logistic regression was used to analyze risk factors for polymicrobial and resistant infections. RESULTS:A total of 487 PJI cases with 608 culture specimens were identified. The mean patient age (and standard deviation) was 70 ± 11 years, with 65% male patients and 35% female patients. All ethnicity data were self-reported. Of the patients in this study, 57% were New Zealand European, 14% were other European, 14% were Pacific Islander, 10% were New Zealand Māori, and 6% were Asian. The most common pathogen for PJIs was Staphylococcus aureus . The proportion of resistant cases (19% to 24%) was consistent across the 24-year period. A prosthesis in situ for <1 year was found to be the most important risk factor for polymicrobial infections (11 times more likely) and resistant infections (3 times more likely). Flucloxacillin monotherapy covered 45% of early PJI cases, 57% of chronic PJI cases, and 79% of late hematogenous cases. In comparison, vancomycin monotherapy provided coverage of ≥78% across all 3 PJI classes, and adding a gram-negative antibiotic such as gentamicin or cotrimoxazole increased coverage to >90%. CONCLUSIONS:Despite the known emergence of resistant organisms in health-care settings, the primary causative microorganisms remained the same in knee PJIs, with no notable increase in resistant cases, over 24 years. Based on the findings of this study, vancomycin with gram-negative coverage is recommended as the empirical treatment of choice in early PJIs, and beta-lactams, such as flucloxacillin and a first-generation cephalosporin (e.g., cefazolin), were found to still be effective for late hematogenous PJIs. For septic PJI, dual therapy with vancomycin and a gram-negative agent is recommended, regardless of infection timing. LEVEL OF EVIDENCE:Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Periprosthetic joint infection (PJI) remains a major source of morbidity, mortality, and economic burden, both in the United States and internationally. Understanding regional microbiology profiles in PJI is essential to assist with empiric antibiotic selection. The purpose of this study was to survey an international database to identify and compare the microbiological profile of hip and knee PJI across international sites. METHODS:A multicenter, international database that included all patients admitted to participating hospitals who had a confirmed diagnosis of PJI was utilized. In the present study, data from four institutions in the following cities were retrospectively reviewed: Melbourne (Australia, n = 167), Groningen (the Netherlands, n = 117), Weston (Florida, United States of America, n = 201), and Charlotte (North Carolina, United States of America, n = 180). The most common organisms identified in hip and knee PJI were compared between institutions. Rates of polymicrobial, fungal, and culture-negative PJI specifically were also evaluated. A total of 665 patients who had PJI were included (311 hip and 354 knee). RESULTS:Coagulase-negative staphylococci were the most frequently isolated pathogens across all centers (26.5 to 38%), followed by Staphylococcus aureus (13 to 27%). Rates of polymicrobial PJI were high and varied widely between institutions (14 to 51%), whereas rates of fungal PJI were low and consistent between regions (1 to 3%). The prevalence of culture-negative PJI varied between 8% (Australia) and 22% (Florida). CONCLUSIONS:While subtle regional differences in the microbiology of PJI exist, Staphylococcus species remained the dominant pathogen, accounting for nearly half of the PJIs at each center. Differences in polymicrobial and culture-negative infections emphasize the impact of institutional and geographic factors, supporting the development of region-specific empiric and prophylactic antibiotic protocols.

BACKGROUND:Perioperative changes in femoro-tibial rotational alignment and the optimal postoperative femoro-tibial rotational alignment following total knee arthroplasty (TKA) are not well characterized. This study aimed to evaluate femoro-tibial rotational alignment following TKA and the effects on postoperative patient-reported outcome measures. METHODS:We analyzed 250 knees undergoing TKA for osteoarthritis. Axial femoro-tibial rotation was determined using the anatomical femoro-tibial rotational angle (FTRA) on pre and postoperative computed tomography. Low rotational offset alignment (LO) and high rotational offset alignment (HO) were defined as a postoperative FTRA of within ± 5° and over ± 5° relative to the preoperative, respectively. A greater than 5° change in intraoperative FTRA was defined as a rotational change (RC). The patient-reported outcome measures were evaluated using the pain, symptoms, and activities of daily living (ADL) subscales of the Knee injury and Osteoarthritis Outcome Score before and one year after surgery. All knees were classified into four groups [LO/RC(-), LO/RC(+), HO/RC(+), and HO/RC(-)] to investigate the relationship between LO/HO and RC. RESULTS:The proportion of knees with LO and HO were 45.6 and 54.4%, respectively. The HO was associated with significantly lower change in pain and change in ADL than was LO (P < 0.01, P = 0.03, respectively). The RC, which occurred in 40.4% of the knees (n = 101), was associated with significantly lower values in change in pain, change in symptom, and change in ADL than was its absence (P < 0.01, 0.02, and 0.01, respectively). The distribution of knees with LO/RC(-), LO/RC(+), HO/RC(+), and HO/RC(-) was 32.0, 13.6, 26.4, and 28.0%, respectively. Only HO/RC(+) knees showed significantly decreased change in pain and change in ADL compared to LO/RC(-) knees (P < 0.01 and = 0.03). CONCLUSIONS:Changes in femoro-tibial rotation and high femoro-tibial rotational offset alignment were associated with worse clinical outcomes following TKA. In particular, high femoro-tibial rotational offset alignment with femoro-tibial RC was associated with the worst clinical outcomes. LEVEL OF EVIDENCE:III (Retrospective Cohort Study).

Aims:Younger patients are at the highest risk of repeat injury after anterior cruciate ligament (ACL) reconstruction. The hamstring tendon autograft remains the most popular choice of graft in the world, but its use in these high-risk patients is controversial. The aim of this study was to compare revision rates between the bone-patellar tendon-bone (BTB) and hamstring tendon autografts in a high-risk patient population. Methods:Prospective data recorded in the New Zealand ACL Registry were analyzed. Primary ACL reconstructions performed between April 2014 and March 2022 were included, allowing for a minimum follow-up of two years. High-risk patients were analyzed using the following criteria: age between 14 and 25 years, ACL rupture during sporting activity, time from injury to surgery within 12 months, grade 2 pivot shift, and a minimum preinjury Marx activity score of 8. The rate of revision was compared between the BTB and hamstring tendon autografts using a univariate chi-squared test and multivariable Cox regression survival analysis to calculate hazard ratios (HRs) with 95% CIs. Results:A total of 3,482 high-risk primary ACL reconstructions were analyzed. A lateral extra-articular procedure was performed in 175 cases with no revisions performed during the study period. The rate of revision was 11.4% (238/2,091) with the hamstring tendon autograft versus 4.3% (60/1,391) with the BTB autograft (p < 0.001). The hamstring tendon autograft had a 2.5-times higher risk of revision compared with the BTB autograft (adjusted HR 2.5 (95% CI 1.9 to 3.3); p < 0.001). The number needed to treat with a BTB autograft to prevent one revision was 14 patients. Conclusion:Isolated hamstring tendon autograft has a high rate of revision and should be avoided in high-risk patients undergoing ACL reconstruction.

Head and neck cancer (HNC) presents significant clinical challenges due to its complex tumor biology, heterogeneous microenvironment, and limited therapeutic outcomes. Hydrogels, an innovative biopolymeric material, have gained considerable attention in both basic and translational oncology owing to their biocompatibility, biodegradability, tunable physicochemical properties, and ability to recapitulate the native tissue environment. This review provides a comprehensive overview of HNC epidemiology, molecular and cellular mechanisms, current and emerging therapeutic approaches, and the defining features of the tumor microenvironment. We then highlight diverse hydrogel systems under development, detailing their structural characteristics and biomedical applications. Hydrogel-based platforms have advanced tumor modeling by enabling three-dimensional (3D) culture systems that more accurately reflect in vivo conditions compared to conventional two-dimensional (2D) models. Cutting-edge technologies, including 3D bioprinting and tumor-on-a-chip microfluidic systems, offer new opportunities for precision modeling and drug testing in HNC. In addition, hydrogels are being engineered for therapeutic applications, such as localized and sustained drug delivery, immunomodulation, and tissue regeneration following tumor resection. Finally, we critically examine the challenges and limitations of current hydrogel-based approaches and outline future directions for their integration into HNC research and clinical practice.

Background: Understanding the causative microorganisms and initiating appropriate empirical antibiotics early are important in the management of knee periprosthetic joint infections (PJIs). The aim of this study was to identify trends in PJI microorganisms and antibiotic resistance profiles over 24 years to guide empirical antibiotic selection. Methods: This study included 487 first-episode PJIs identified between 2000 and 2023 following primary total knee arthroplasty (TKA) at 3 large tertiary hospitals. PJIs were classified using the Tsukayama classification, which is based on the timing from the primary TKA and the source of infection. Multivariable logistic regression was used to analyze risk factors for polymicrobial and resistant infections. Results: A total of 487 PJI cases with 608 culture specimens were identified. The mean patient age (and standard deviation) was 70 ± 11 years, with 65% male patients and 35% female patients. All ethnicity data were self-reported. Of the patients in this study, 57% were New Zealand European, 14% were other European, 14% were Pacific Islander, 10% were New Zealand Māori, and 6% were Asian. The most common pathogen for PJIs was Staphylococcus aureus . The proportion of resistant cases (19% to 24%) was consistent across the 24-year period. A prosthesis in situ for <1 year was found to be the most important risk factor for polymicrobial infections (11 times more likely) and resistant infections (3 times more likely). Flucloxacillin monotherapy covered 45% of early PJI cases, 57% of chronic PJI cases, and 79% of late hematogenous cases. In comparison, vancomycin monotherapy provided coverage of ≥78% across all 3 PJI classes, and adding a gram-negative antibiotic such as gentamicin or cotrimoxazole increased coverage to >90%. Conclusions: Despite the known emergence of resistant organisms in health-care settings, the primary causative microorganisms remained the same in knee PJIs, with no notable increase in resistant cases, over 24 years. Based on the findings of this study, vancomycin with gram-negative coverage is recommended as the empirical treatment of choice in early PJIs, and beta-lactams, such as flucloxacillin and a first-generation cephalosporin (e.g., cefazolin), were found to still be effective for late hematogenous PJIs. For septic PJI, dual therapy with vancomycin and a gram-negative agent is recommended, regardless of infection timing. Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Non-steroidal anti-inflammatory drugs (NSAIDs) are a mainstay of postoperative pain control following rotator cuff repair, despite a thorough understanding of their effects on clinical outcomes. This paper aims to assess the influence of NSAID use on pain and functional outcomes for 5 years postoperatively. METHODS:Patients undergoing rotator cuff repair throughout New Zealand were enrolled in this prospective cohort study from March 1, 2009, to December 31, 2010, with 2,533 primary repairs included. Follow-up was 81% at 5 years. Demographic, preoperative, and intraoperative data as well as NSAID use duration were recorded, with follow-up at 6, 12, 24 months, and 5 years, measuring Flex Shoulder Function and visual analog scale pain score. RESULTS:In total, 72% of the study population used NSAIDs postoperatively; 18% took NSAIDs for up to 2 weeks in duration, 21% 3-6 weeks, 12% 7 weeks to 3 months and 21% over 3 months. NSAID use for longer than 2 weeks was associated with poorer function at 6 and 12 months postoperatively, with use longer than 6 weeks associated with poorer function at 6, 12, 24 months, and 5 years. Improvement in function was significantly lower in those taking NSAIDs for more than 3 months (P=0.04). A higher rate of stiffness was seen in the NSAID group (P<0.001). CONCLUSIONS:Use of NSAIDs longer than 6 weeks following rotator cuff repair was associated with poorer functional outcomes, and higher pain with extended use. This data raises concern regarding potential detrimental effects of NSAIDs following rotator cuff repair, and further research is required to determine their safe duration of use. Level of evidence: II.

Periodontitis is a biofilm-induced chronic inflammatory disease, characterized by gingival inflammation and alveolar bone loss. According to a national survey, approximately half of the U.S. adults are affected by periodontal disease. To effectively prevent and treat periodontitis, it is essential to address its underlying causes. The primary etiological factors include polymicrobial synergy and dysbiosis of the oral microbiota, and a dysregulated immune response. The standard therapeutic approach, mechanical removal of biofilm through debridement, sometimes demonstrates limited efficacy, particularly in cases of severe periodontitis, which may require adjunctive or additional therapy. Emerging evidence indicates that periodontal tissue destruction is initiated by biofilm but primarily driven by a sustained, dysregulated host inflammatory response characterized by excessive cytokine production, osteoclast activation, and impaired inflammation resolution. In recent years, research has focused on targeting both the oral microbiota and immune response by utilizing antimicrobial therapeutics to diminish bacterial load and by modulating immune activity. Specifically, host modulation therapies (HMTs), such as the delivery of anti-inflammatory cytokines, nonsteroidal anti-inflammatory drugs (NSAIDs), low-dose doxycycline, and lipid mediators, via various techniques, have been explored. However, challenges associated with its use encompass adverse effects resulting from prolonged administration, and systemic delivery methods are associated with an elevated risk of infection and the potential development of malignancy, as well as the disease rebound after cessation of treatment. This review examines current trends in HMTs for periodontitis and identifies potential limitations of these approaches. The insights gained may contribute to the development of improved strategies to enhance periodontal treatment outcomes.

While immunotherapy is a promising treatment strategy for cancer, the majority of head and neck squamous cell carcinoma (HNSCC) patients treated with single-agent immunotherapy do not respond. Therefore, researchers are investigating combination treatments with immunostimulatory molecules that can maximize anti-tumor responses. Cyclic dinucleotides (CDNs) are STING agonists that hold promise in combination approaches, but they require frequent intratumoral administration when used in both preclinical models of HNSCC and clinical trials. To reduce administration frequency, we have created a peptide hydrogel-liposome composite system, K2-Lip(CDN), for local and prolonged availability of CDN. We investigated the loading limits of cationic liposomes in both anionic (E2) and cationic (K2) peptide hydrogels and found that E2 caused aggregation to occur at the desired lipid:peptide molar ratio, which led to our use of K2 in the composite system. At a molar ratio of 8:1 lipid:peptide, K2-Lip(CDN) formed a self-healing composite hydrogel and resulted in prolonged release of CDN in vitro and indocyanine green (ICG) in vivo. This composite material resulted in cellular cytotoxicity in ROC1 oral cancer cells in vitro and extended survival in an aggressive ROC1 tumor-bearing murine model compared to a single CDN injection. The overall survival using only a single dose of K2-Lip(CDN) was equivalent to that achieved with six repeated doses of CDN. The material properties and extended-release capabilities displayed by peptide hydrogel-liposome composite systems could translate to broad treatment applications that require the delayed release of localized therapeutics.

Purpose: Early reconstruction for anterior cruciate ligament (ACL) rupture may be controversial, with some clinicians opting for a trial of non-operative management first. The impact of delayed surgery on outcomes is unclear, but it may be associated with an increase in secondary intra-articular pathology involving the menisci and cartilage. This study aimed to analyze the association between the timing of surgery and outcomes, including revision ACL reconstruction, concomitant meniscal and chondral injuries. Methods: Prospective data recorded in the New Zealand ACL Registry were analyzed. Primary ACL reconstructions performed between April 2014 and December 2022 were included. Timing of surgery was categorized into five groups: <= 6 weeks, 6 weeks to 3 months, 3-6 months, 6-12 months and >12 months. Revision rates and incidence of concomitant meniscal and chondral injury were compared between the five groups of surgical timing. Results: A total of 15,586 primary ACL reconstructions were analyzed, of which 1263 were performed within 6 weeks (8%), 3718 between 6 weeks to 3 months (24%), 5129 between 3 and 6 months (33%), 3223 between 6 and 12 months (21%) and 2253 more than 12 months (14%). The incidence of medial meniscal tears was greatest when surgery was delayed 6-12 months (40%, adjusted odds ratio [aOR] = 1.1, p = 0.01) and more than 12 months after injury (53%, aOR = 2.0, p < 0.001). Delayed surgery more than 3 months was associated with an increasing incidence of chondral injury (aOR > 1.3, p < 0.001). Revision rates were lowest in patients who underwent delayed surgery more than 12 months after injury (adjusted hazard ratio [HR] = 0.6, p < 0.001), but differences in activity levels, age, sex and graft choice were noted. Conclusion: Delayed ACL reconstruction is associated with a greater incidence of concomitant medial meniscal and chondral injury and should be considered when trialling non-operative management for ACL rupture.

PURPOSE:For unicompartmental knee arthroplasty (UKA), patient selection using correct indications can optimise postsurgical outcomes. The current gold standard for assessing eligibility is with radiographs; however, magnetic resonance imaging (MRI) may allow for more accurate assessments of cartilage damage. This study aimed to evaluate the utility of MRI for preoperative assessment of medial UKA patients by (1) comparing osteoarthritis severity of the medial, lateral and patellofemoral (PF) compartments when assessed using MRI compared with standard radiographs, and (2) investigating associations of these two assessments with postoperative clinical outcomes. METHODS:This study had ethical approval. A retrospective review was performed for 88 primary medial UKA between 1 January 2017 and 31 December 2021. The main outcome measures were preoperative cartilage loss and patient-reported clinical outcomes. Preoperative cartilage loss was recorded using the International Cartilage Repair Society (ICRS) classification using MRI, and Kellgren-Lawrence (K-L) scores from radiographs. Patient-reported clinical outcomes were measured using preop, early (6-week) and late (1- or 2-year) Oxford Knee Score (OKS) change scores. RESULTS:The use of MRI has improved accuracy over radiographs. In the medial compartment, 37 (44%) patients had less severe radiographic K-L scores (1-3); however, all patients had the most severe MRI ICRS scores (4). For patients with mild K-L scores (0 and 1), 20 (43%) and 7 (78%) patients had more severe ICRS scores (3 and 4) within their lateral and PF compartments, respectively. No associations were found between ICRS or K-L scores and OKS for any compartments. CONCLUSIONS:Assessment of medial cartilage thickness loss using MRI provides additional utility over standard radiographs in preoperative assessments of medial UKA patients. However, evidence of disease in the PF compartment assessed using MRI should not be considered a contraindication for UKA. LEVEL OF EVIDENCE:Level III, retrospective cohort study.

While large-scale data on total knee arthroplasty (TKA) failures are well established in national joint registries, recorded reasons for failure lack granularity. Understanding reasons for TKA failures is crucial for optimising patient outcomes. This study aimed to identify reasons for TKA failures and trends in failure over the last two decades. A total of 20,235 primary TKAs were identified across the three Auckland tertiary hospitals from 2000–2023. Clinical coding and national joint registry data were cross-referenced to identify any ‘failures’, defined as subsequent revision or reoperation for periprosthetic joint infection (PJI). Failure reasons were determined from systematic review of operative notes, microbiology, and imaging. For revisions outside of Auckland, records were obtained from operating surgeons. For analysis, failures were grouped by time from index procedure (five-year bands) and by year (2000-2014, 2014-2023) and compared using chi-squared tests. A total of 714 failures were identified (3.5%). The three most common reasons were PJI (51.2%), patellofemoral (PF) arthrosis (15%), and aseptic loosening (12.2%). The proportion of PJI failures was greatest at early follow-up (56% within 5 years of index procedure vs. 21% at 15-20 years, p<0.001), whereas aseptic loosening was more prevalent at late follow-up (29% at 15-20 years vs. 9% within 5 years, p<0.001). PF arthrosis rates were consistent across 20 years (p=0.14). PJI failures increased from 43% of all failures in 2000-2014 to 61% in 2014-2024 (p=0.02). There was no difference for aseptic loosening (2000-2014: 14% vs. 2014- 2024: 10%, p=0.51) or PF arthrosis (2000-2014: 14% vs. 2014-2024: 16%, p=0.84). PJI remains the leading cause for failure, while proportions of failures due to aseptic loosening and PF arthrosis are unchanged over the last two decades. These findings emphasize the need for continued optimisation of infection control, implant development and patient selection strategies for TKA.

BACKGROUND:Effective postoperative pain management is important following primary total knee arthroplasty (TKA). Intraosseous regional administration (IORA) of antibiotics in TKA results in higher local tissue concentrations, potentially improving efficacy. We investigated using IORA diclofenac to improve postoperative pain management in TKA compared to intravenous (IV) diclofenac. METHODS:There were 46 primary TKA patients (23 per group) enrolled in a prospective, double-blinded, randomized controlled trial. The intervention group received 75 mg IORA diclofenac and an IV normal saline placebo. The control group received 75 mg IV diclofenac and an intraosseous normal saline placebo. Pain levels were measured on a visual analog scale for pain (VAS-P) until postoperative day (POD) seven. The secondary outcomes included opioid consumption, quality of recovery-15, impact of pain on walking and sleep, length of admission, patient satisfaction, the Knee Injury and Osteoarthritis Outcome Score for Joint Replacements, and Oxford Knee Score. RESULTS:Intervention group visual analog scale for pain scores (mm, [95% confidence interval]) were lower at one (21.2 [16.3, 31.4] versus 40.2 [30.8 to 50.8]; P = 0.007), 12 (18.2 [12.1 to 25.6] versus 36.5 [27.6 to 46.6]; P = 0.002), and 24 hours (21.3 [14.6 to 29.2] versus 39.5 [30.2 to 50]; P = 0.003), and POD one (23.5 [17.8 to 30] versus 35.4 [28.3 to 43.3]; P = 0.01). The intervention group consumed fewer opioids (mean morphine milligram equivalent in mg) from POD zero (20.2 [12.4 to 28.0] versus 45.3 [37.7 to 53.0]), POD one (27.7 [19.2 to 34.8] versus 43 [35.4 to 50.6]), POD two (32.1 [24.3 to 39.9] versus 51.5 [43.9 to 59.1]), and POD three (27.4 [19.6 to 35.2] versus 41.3 [33.7 to 48.9]). Moreover, they demonstrated better quality of recovery-15 scores (P = 0.04), POD one walking (P = 0.001) and sleeping (P = 0.003), Knee Injury and Osteoarthritis Outcome Score for Joint Replacements scores (P = 0.03), and patient satisfaction (P = 0.04) at 2 weeks postsurgery. CONCLUSIONS:The IORA diclofenac provided enhanced early postoperative pain relief and reduced opioid consumption, with better early knee function and patient satisfaction following TKA.

Aims Computer-assisted technology has greater surgical accuracy for total knee arthroplasty (TKA); however, it is unclear if this is associated with better patient outcomes. There is a paucity of data comparing robotic arm-assisted TKA (RA-TKA) and computer-navigated TKA (nav-TKA). The aim of this study was to compare mid-term outcomes of image-based semiactive RA-TKA with imageless nav-TKA in a large patient cohort. Methods Patient characteristics, surgical variables, complications, and patient-reported outcomes were recorded for 1,434 primary TKAs (388 RA-TKAs; 1,046 nav-TKAs) performed between November 2019 and October 2023 at a large tertiary hospital. Data were analyzed using Fisher's exact or Mann-Whitney U tests. Analyses were performed for cohorts matched for baseline demographics and follow-up time. Results Compared to nav-TKA, matched RA-TKA cases had a shorter operating time (86.8 mins (SD 18.5) vs 93.3 mins (SD 23.6); p < 0.001), shorter length of stay (3.1 days (SD 1.4) vs 3.4 days (SD 1.6); p < 0.001), and fewer manipulations under anaesthesia (15 (4%) vs 29 (8%); p = 0.042). There were similar frequencies of inpatient complications (15 (4%) vs 22 (6%); p = 0.312), emergency department (ED) presentations (32 (8%) vs 41 (11%); p = 0.325), and revisions (five (1%) vs two (0.5%); p = 0.451) for RA-TKA and nav-TKA, respectively. At two years, RA-TKA patients reported higher Oxford Knee Score (41.2 (SD 6.7) vs 39.3 (SD 7.7); p = 0.003), EuroQol five-dimension questionnaire index (EQ-5D) (0.88 (SD 0.16) vs 0.82 (SD 0.20); p = 0.010), and EQ-5D Health (80.6 (SD 15.5) vs 77.2 (SD 16.9); p = 0.035), and lower levels of pain (11.0 (SD 18.2) vs 15.3 (SD 20.9); p < 0.001). Fewer RA-TKA patients were dissatisfied at six months (3% vs 7%; p = 0.034) and two years (3% vs 9%; p = 0.019). Conclusion The findings suggest that image-based semiactive robotic assistance for TKA has benefits over imageless computer-assisted navigation, including shorter hospital length of stay, fewer MUAs, and improved mid-term patient-reported outcomes, but similar complications and ED presentations. Cost analysis showed that RA-TKA can have cost benefits at high-volume centres, however this needs to be weighed against the high initial cost of RA-TKA systems.

BACKGROUND:Total knee (TKA) and total hip arthroplasty (THA) can be definitive end-stage procedures following hip and knee trauma. In Aotearoa, injury-related costs are funded by the Accident Compensation Corporation (ACC). This study aims to understand the magnitude, characteristics and outcomes of post-traumatic TKA and THA in Aotearoa. METHODS:Retrospective data from ACC and the New Zealand Joint Registry for post-traumatic primary TKA and THA between 1st January 2000 and 31st December 2020 was analysed. RESULTS:Over 20 years, 10 179 primary TKA and 5611 primary THA were funded, totalling 918 million New Zealand Dollars. Social costs (weekly compensation and rehabilitation) exceeded medical costs (medical treatment, hospital, and surgical costs). Most individuals were European males between 55 and 65 years of age at the time of surgery. Following surgery, 21% TKA and 11% THA required more than 6 months of workers' compensation, with risk factors being younger age (TKA RR 1.04, THA RR 1.03), male sex (TKA RR 1.12, THA RR 1.23), and heavy occupations (TKA RR 1.50, THA RR 1.57). For TKA, 10-year revision-free implant survival was 88.7% (95% CI: 0.88-0.90) and for THA 77.7% (95% CI: 0.76-0.79), which is poorer than the 10-year registry survivorship for arthroplasty performed for primary osteoarthritis of 95.7% for TKA (P < 0.001, RR 1.03-1.05) and 94.1% for THA (P < 0.001, RR 1.12-1.17). CONCLUSION:Social costs contribute to a substantial economic burden in post-traumatic lower limb arthroplasty. Targeted rehabilitation strategies are crucial to improving recovery and minimizing time off work.