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BACKGROUND: Although both high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) can be utilized to treat unicompartmental osteoarthritis (OA) in select patients, the early complication rates between the 2 procedures are not well understood. Understanding of the complication profiles for both procedures would help clinicians counsel patients with unicompartmental knee OA who may be eligible for either treatment option. PURPOSE: To compare the 30-day complication rates after HTO versus UKA for the treatment of knee OA using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: NSQIP registries between 2006 and 2019 were queried using Current Procedural Terminology codes to identify patients undergoing HTO and UKA for knee OA. Patients >60 years of age were excluded. Patient demographics, preoperative comorbidities, and intraoperative data were collected. Postoperative 30-day complications, including venous thromboembolism (VTE), urinary tract infection (UTI), transfusion, surgical-site infection (SSI), and reoperations were recorded. Complication rates between treatment groups were compared using a multivariate logistic regression model adjusted for sex, age, body mass index, steroid use, respiratory status (smoking/dyspnea/chronic obstructive pulmonary disease), diabetes, and hypertension. RESULTS: A total of 156 patients treated with HTO and 4755 patients treated with UKA for knee OA were identified. Mean patient ages were 46 years for the HTO group and 53.4 years for the UKA group. Operative time was significantly longer in the HTO group versus the UKA group (112 minutes vs 90 minutes; P < .001). Multivariate analyses found no significant differences in VTE (1.3% vs 0.6%), UTI (0.6% vs 0.3%), transfusion (0.6% vs 0.2%), deep SSI (0.6% vs 0.1%), and reoperation (1.3% vs 1%) rates between HTO and UKA groups. The HTO group had a higher rate of superficial SSI compared with the UKA group (2.6% vs 0.6%; P = .006) (adjusted odds ratio, 4.2; 95% CI, 1.4-12.5; P = .01). CONCLUSION: There were no differences in 30-day VTE, UTI, transfusion, deep SSI, and reoperation rates for HTO versus UKA in the treatment of knee OA. HTO was associated with a higher rate of superficial SSI compared with UKA. These findings serve to guide clinicians in counseling patients regarding the early risks after HTO and UKA.

BACKGROUND: Unicompartmental knee arthroplasty has been paid more and more attention because of its advantages of fewer traumas, less blood loss, less complications, faster recovery, excellent knee function and high prosthetic survival rate. Most of the relevant reports focused on its clinical effect, but the changes in the levels of relevant inflammatory cytokines in patients after unicompartmental knee arthroplasty were rarely reported. OBJECTIVE: To investigate the effect of unicompartmental knee arthroplasty in patients with medial compartment osteoarthritis of the knee and the changes of interleukin-1, interleukin-6, and tumor necrosis factor-α levels. METHODS: A total of 30 patients with medial compartment osteoarthritis of the knee who received unicompartmental knee arthroplasty from September 2021 to March 2023 and met the inclusion criteria were selected as the study subjects. Medial angle of proximal tibia, femoral and tibial angle, pain visual analog scale score, hospital for special surgery score, knee joint range of motion, synovial fluid interleukin-1, interleukin-6, and tumor necrosis factor-α levels before and after surgery were compared and statistically analyzed. RESULTS AND CONCLUSION: (1) All 30 patients had grade I wound healing. All patients were followed up for more than 6 months after surgery. There were no complications such as prosthesis loosening and dislocation of prosthesis liner in all patients. (2) The medial proximal tibia angle and the femoral and tibial angles measured after operation were significantly improved (P < 0.05). (3) The visual analog scale score, hospital for special surgery score and range of motion measured at 1, 3, and 6 months after operation were better than those before operation (P < 0.05), and showed a gradual improvement (P < 0.05). (4) The levels of interleukin-1, interleukin-6, and tumor necrosis factor-α in synovial fluid at 3 and 6 months after operation were decreased gradually compared with those before operation (P < 0.05) and showed a gradual downward trend at each time point after operation. (5) It is indicated that unicompartmental knee arthroplasty can effectively treat medial compartment osteoarthritis of the knee, significantly relieve pain, restore knee joint function, improve knee varus deformity and lower limb strength line, and reduce the levels of inflammatory cytokines interleukin-1, interleukin-6, and tumor necrosis factor-α in joints to a certain extent. [ABSTRACT FROM AUTHOR]

Background: This study systematically reviews recent research comparing clinical outcomes and gait function changes in patients undergoing total knee arthroplasty (TKA) versus unicompartmental knee arthroplasty (UKA). Methods: A systematic search of the Web of Science, PubMed, and Embase databases was conducted, covering publications from January 2013 to September 2024, to identify studies evaluating changes in clinical scores and gait parameters in patients undergoing TKA or UKA. Following stringent selection criteria, data were synthesized from studies involving 171 TKA and 148 UKA patients, focusing on reported gait outcomes and aggregating findings for comprehensive analysis. Direct comparisons between TKA and UKA were performed to assess differences in clinical scores and gait parameters, aiming to elucidate the relative efficacy of each surgical approach and provide robust evidence for clinical decision-making. Results: Ten studies met the inclusion criteria for post-operative gait outcome comparisons between TKA and UKA, with seven studies also addressing clinical scores. One study reported greater improvement in WOMAC scores for the UKA group at 6 months post-operation (P < 0.05), while another found superior EQ-5D scores for UKA patients at 1 year post-surgery (P < 0.05). Conversely, five studies found no significant differences in clinical scores between groups at 1 year (P > 0.05). All ten studies assessed gait parameter recovery, with three studies showing no significant differences at 1 year (P > 0.05). However, seven studies identified superior gait recovery in the UKA group across various parameters, including walking speed, step and stride length, single support time, heel strike force, knee joint range of motion, knee flexion angles during different gait phases, peak knee adduction moment, peak tibial internal rotation moment, gait symmetry, and stride length symmetry (P < 0.05). Conclusions: The analysis indicates that UKA offers certain advantages in post-operative gait improvements compared to TKA, though these do not translate into significant differences in conventional clinical scoring systems. To enhance the reliability and generalizability of these findings, future studies should involve larger-scale, prospective randomized controlled trials. [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) is a surgical procedure for managing osteoarthritis of one joint compartment, most commonly the medial side. This systematic review investigates the causes of UKA revision. The outcomes of interest were establishing the revision rate, time to revision, and the most common causes of revision in the long- and midterm follow-up. Methods: This study was conducted according to the 2020 PRISMA statement. In October 2024, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. All the clinical studies investigating the rate and causes of revision in UKA were accessed. Only studies with a minimum of 10 years of follow-up were considered. Results: Data from 56 studies (13,540 patients) were collected. Of them, 65.6% were women. The mean length of the follow-up was 13.1 ± 3.0 years. The mean age of the patients was 65.6 ± 5.6 years, and the mean BMI was 28.5 ± 2.2 kg/m2. Revisions were performed in 8.8% (2641 of 30,140) of implanted UKAs. The mean time to revision was 6.5 ± 2.6 (range, 2.5 to 13.0) years. Conclusion: 8.8% (2641 of 30,140) of UKAs were revised at a mean time of 6.5 ± 2.6 years. Level of evidence: Level IV, systematic review. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of patellar morphology on functional outcomes and patellofemoral joint alignment after unicompartmental knee arthroplasty (UKA). Methods: This study retrospectively analyzed the clinical and imaging data of 207 patients with osteoarthritis of the unicompartment of the knee who underwent UKA between September 2020 and April 2023. Patients were divided into three groups according to the Wiberg classification: group W1 (I, n = 47), group W2 (II, n = 117), and group W3 (III, n = 43). Knee function was assessed using the Hospital for Specialty Surgery (HSS) knee score and Feller patellar score, and the incidence of anterior knee pain after surgery was recorded and compared. Imaging parameters such as patellar tilt angle (PTA), lateral patellofemoral angle (LPA) and Insall-Salvati ratio (ISR) were measured to assess patellofemoral joint alignment. Results: The HSS scores of the three groups were not statistically different; the postoperative Feller scores of the group W3 differed significantly from those of the other two groups. The incidence of early postoperative anterior knee pain was higher in the group W3 than in the other two groups. The difference between preoperative PTA, postoperative PTA and preoperative LPA in the group W3 and the other two groups was statistically significant. Conclusion: Patients with Wiberg III patellae exhibited worse patellar scores, as well as more anterior knee pain and patellar tilt postoperatively. This finding highlights the need for individualized treatment to the Wiberg III patella during UKA to enhance surgical outcomes. [ABSTRACT FROM AUTHOR]

Purpose: This retrospective single-center study aimed to investigate incidence and risk factors influencing tibial periprosthetic fractures (TPF) in Oxford unicompartmental knee arthroplasty (UKA), with a specific focus on tibial component positioning and sizing. Methods: A total of 2063 patients with medial UKA using the Oxford® mobile partial knee implant were analyzed between July 2014 and September 2022. Various preoperative and postoperative radiographic parameters determining pre- and postoperative alignment and implant positioning, incidence and characteristics of periprosthetic fractures, and patient demographics were assessed. Statistical analyses, including Mann–Whitney U test and logistic regression, were conducted to identify significant associations and predictors of tibial fractures. Results: Of the 1853 cases that were finally included in the study, 19 (1%) patients experienced TPF. The fracture group presented with a significantly shorter relative mediolateral and posteroanterior distance between the keel and cortex [mediolateral: 23.3% (23.2–24.8%) versus 27.1% (25.7–28.3%), p < 0.001; posteroanterior: 8.4% (6.3–10.3%) versus 10.0% (9.8–10.1%), p = 0.004]. Additionally, an increased posterior tibial slope in pre- and postoperative radiographs [preoperative: 10.4° (8.6–11.1°) versus 7.7° (5.4–10.0°), p < 0.001; postoperative 9.1° ± 3.1° versus 7.5° (5.9–9.0°), p = 0.030] was observed in the fracture group. Furthermore, the use of smaller-sized implants (AA) was associated with higher fracture rates (p < 0.001). Anatomical variants, such as a medial overhanging tibial plateau, were not observed. Conclusions: In UKA, type Oxford TPF are linked to shorter mediolateral and posteroanterior keel-cortex distances, increased pre- and postoperative PTS, and small implant sizes (AA). Fracture lines often extend from the distal keel to the medial tibial cortex. These findings emphasize the importance of precise implant positioning and sizing to minimize fracture risk. Level of evidence Retrospective single-center study, III. [ABSTRACT FROM AUTHOR]

Background: Periarticular local infiltration analgesia (LIA) has become a widely used method for postoperative pain management after unicompartmental knee arthroplasty (UKA). However, the efficacy of using magnesium sulphate or sodium bicarbonate in LIA cocktails during UKA is not yet clear. The present study aimed to evaluate whether the modified LIA has advantages in pain control and joint function recovery after UKA surgery. Methods: Sixty-one patients who underwent UKA were enrolled and randomly assigned to receive periarticular infiltration of a modified cocktail (comprising ropivacaine, epinephrine, dexamethasone, magnesium sulphate, and sodium bicarbonate) or a conventional cocktail (comprising ropivacaine, epinephrine, dexamethasone, ketorolac, and morphine). The outcomes included the consumption of patient-controlled intravenous analgesia (PCIA) medication used for postoperative analgesia, pain score, early joint functional recovery, discharge time, and complication rates. Results: In the first 12 h after surgery, the conventional cocktail was not superior to the modified cocktail in terms of visual analogue scale (VAS) scores. However, beginning on the second postoperative day, the analgesic effect was significantly prolonged in the modified group, leading to lower VAS scores and better knee functional recovery. Additionally, patients in the modified group required less pain medication via PCIA, both within the first 24 h and cumulatively up to 48 h after surgery. Both groups had similar rates of complications. Conclusions: The present modification of a conventional cocktail significantly prolonged the analgesic effect and reduced pain medication consumption after UKA surgery, which was associated with better functional recovery in the early postoperative days. Trial registration: Chinese Clinical Trial Registry, ChiCTR2200060500. 21 March 2023. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to elucidate differences and similarities in revision rates amongst studies and national registers featuring total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). Thereby comparability and reproducibility between study and register findings should be created. Materials and Methods: Clinical studies published between 2004 and September 2023 involving TKA or UKA were reviewed for total arthroplasty numbers, revision rates and demographic data. Findings were calculated as "revisions per 100 component years (CY)" and divided according to the nationality of the center. National arthroplasty registers were searched for numbers of arthroplasties and revisions alongside with demographic data. Revision rates in registers were compared to one another and comparison to revision rates from collected studies was drawn. Results: After evaluation, 98 studies and seven registers met our inclusion criteria and were included in this study. Cumulative percent revision rate in studies was 3.35% after a mean follow-up of 5.7 years, corresponding to 0.71 revisions per 100 CY for TKA and 7.67% after a mean follow-up of 4.9 years, corresponding to 1.3 revisions per 100 CY for UKA. Registers showed mean overall revision rates of 5.63% for TKA and 11.04% for UKA. Conclusions: A positive correlation of revision rates of TKA and UKA in studies and registers was found, with overall revision rates of UKA comparted to TKA being 2.29 times higher in clinical studies and 1.96 times higher in registers. Revision rates in registers were 1.56 times higher than presented in clinical studies. [ABSTRACT FROM AUTHOR]

Introduction: This study conducted a Bayesian network meta-analysis (NMA) to compare the imaging and functional outcomes of patient-specific instrument-assisted unicompartmental knee arthroplasty (P-UKA), robot-assisted unicompartmental knee arthroplasty (R-UKA), and conventional unicompartmental knee arthroplasty (C-UKA). Materials and methods: A comprehensive search was performed on five electronic databases and major orthopedic journals as of September 24, 2023. We included randomized controlled studies featuring at least two interventions of P-UKA, R-UKA, or C-UKA. Primary outcomes encompassed the deviation angle of hip-knee-ankle angle, as well as the coronal and sagittal plane alignment of femoral and tibial components. Secondary outcomes included patient-reported outcome measures (PROM), surgery time, revision rate, and complication rate. Bayesian framework was employed for risk ratio (RR) or mean deviation (MD) analysis, and treatment hierarchy was established based on rank probabilities. Results: This NMA included 871 knees from 12 selected studies. In sagittal plane, R-UKA exhibited a significantly reduced deviation angle of femoral component compared to P-UKA (MD: 4.16, 95% CI: 0.21, 8.07), and of tibial component in comparison to C-UKA (MD: -2.45, 95% CI: -4.20, -0.68). Notably, the surgery time was significantly longer in R-UKA than in C-UKA (MD: 15.98, 95% CI: 3.11, 28.88). However, no significant differences were observed in other outcomes. Conclusion: Compared with P-UKA or C-UKA, R-UKA significantly improves the femoral and tibial component alignment in the sagittal plane, although this does not translate into discernible differences in functional outcomes. Comprehensive considerations of economic and learning costs are imperative for the judicious selection of the appropriate procedure. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis has become the predominant manifestation of arthritic conditions on a worldwide scale and serves as a significant instigator of pain, impairment, and increasing socio-economic strain on a global level. The ongoing discourse on the choice between total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) for patients suffering from anterior medial osteoarthritis continues to ignite scholarly controversy. Our objective was to assess and compare the clinical outcomes of UKA and TKA within the same patient, hereby offering a novel perspective on this topic. Materials and methods: Fifty-seven individuals who underwent TKA on one knee and UKA on the other knee at the Department of Orthopaedics, First Hospital of Hebei Medical University between March 2019 and March 2024 were analysed for this retrospective study. We conducted a comprehensive examination and evaluation of perioperative laboratory assessments, radiological examinations, knee functionality, contentment levels, and postoperative complications within the two groups. Results: Following surgical procedures, levels of hemoglobin, red blood cells, and albumin were found to be elevated in the UKA group when compared to the TKA group (hemoglobin: 121.2 ± 12.54 vs. 110.1 ± 13.21 g/L; red blood cells: 4.0 ± 0.47 vs. 3.6 ± 0.42 *1012/L; albumin: 37.7 ± 5.66 vs. 35.3 ± 5.23 g/L). There is a significant difference in the hip-knee-ankle angles between the postoperative UKA group and the TKA group (5.3 ± 3.46° vs. 4.1 ± 2.86°, p < 0.05). There existed no notable disparity in postoperative visual analog scale, knee society score, and forgotten joint score between the two groups. However, a remarkable variance was observed in postoperative range of motion between the two groups (116.4 ± 5.96° vs. 108.4 ± 5.32°). Conclusion: We found that UKA resulted in less physical strain, less postoperative inflammatory response, improved joint mobility, although with less effective lower limb force line correction compared to TKA. Many patients have shown a preference for UKA and express higher levels of satisfaction with the procedure. [ABSTRACT FROM AUTHOR]

• Identifying the influences of kinesiophobia based on social cognitive theory. • Incorporating positive structures into fear avoidance modelling. • Pain resilience, rehabilitation self-efficacy chain-mediates between social support and kinesiophobia. • Satisfactory social support enhances the pain resilience and rehabilitation self-efficacy, so as to reduce kinesiophobia. To analyze the path relationships among influencing factors for kinesiophobia in knee arthroplasty patients through a structural equation model. The occurrence of kinesiophobia significantly impacts the rehabilitation process of knee arthroplasty patients. However, there is still a need to determine factors that contribute to reducing kinesiophobia. A cross-sectional study was conducted and reported following the STROBE guideline. Between February 2022 to October 2022, 162 total knee arthroplasty (TKA) patients and 81 unicompartmental knee arthroplasty (UKA) patients completed a survey. A structural equation modeling (SEM) approach was utilized to analyze the relationships between kinesiophobia and influencing factors (social support, pain resilience, and rehabilitation self-efficacy). Furthermore, multi-group SEM analysis was conducted to examine whether the model equally fitted patients in different types of knee arthroplasty. The direct negative effects of rehabilitation self-efficacy (β = −0.535) and pain resilience (β = −0.293) on kinesiophobia were observed. The mediating effect (β = −0.183) of pain resilience and rehabilitation self-efficacy between social support and kinesiophobia was also significant. The SEM model achieved an acceptable model fit (χ2 = 35.656, RMSEA = 0.031, χ2/df = 1.230, GFI = 0.972, NFI = 0.982, IFI = 0.997, CFI = 0.996). In multicohort analysis, no significant differences were observed among knee arthroplasties (TKA, UKA) (Δχ2 = 4.213, p = 0.648). Satisfactory social support enhances pain resilience and rehabilitation self-efficacy, so as to reduce kinesiophobia. Future interventions that directly target the assessment and management of kinesiophobia, available social support may help reduce kinesiophobia, and pain resilience and rehabilitation self-efficacy may be critical factors in managing kinesiophobia. Reducing kinesiophobia in knee arthroplasty patients requires satisfactory social support, pain resilience, and rehabilitation self-efficacy. Therefore, healthcare organizations may implement initiatives to reduce kinesiophobia by taking these factors into account. [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are treatment options for patients with medial spontaneous osteonecrosis of the knee (SONK). Purpose: To compare the clinical outcomes after UKA and HTO in patients with SONK. Study Design: Cohort study; Level of evidence, 3. Methods: This retrospective study included 42 patients who had undergone Oxford UKA and 40 patients who had undergone opening-wedge HTO between 2014 and 2020. All patients were diagnosed with isolated medial SONK without subchondral collapse of the femoral condyle and tibial plateau. The patients were preoperatively and postoperatively evaluated using the Lysholm knee scoring system, the Western Ontario and McMaster Universities Osteoarthritis Index, and a numeric rating scale assessing patient satisfaction. Results: Patients in the UKA group were significantly older than those in the HTO group (median age, 71.5 years [IQR, 68.0-76.5 years] vs 65.0 years [IQR, 60.0-70.0 years], respectively; P <.001). The median follow-up time was 3.78 years (IQR, 2.45-4.53 years) for the UKA group and 3.87 years (IQR, 2.90-5.60 years) for the HTO group. Significant improvements in functional scores were observed in both the UKA and HTO groups (P <.001 for all), with no significant between-group differences in scores at the final follow-up (≥2 years after surgery). The satisfaction rate was similar (80.95% for UKA and 75.0% for HTO). Conclusion: According to the study results, significant improvements in clinical outcomes were seen after opening-wedge HTO with microfracture for a younger group of patients with SONK without subchondral collapse, while Oxford UKA had a comparable effect on an older group of patients. Both UKA and HTO were found to be viable surgical approaches for SONK at short- to midterm follow-up. [ABSTRACT FROM AUTHOR]

BACKGROUND: With the further development of minimally invasive concepts, unicompartmental knee arthroplasty has become an important treatment for osteoarthritis of the knee; however, early postoperative pain adversely affects the recovery process, so effective analgesic measures are necessary. Femoral nerve block and cocktail therapy are common analgesic methods for unicompartmental knee arthroplasty, but there is a lack of studies confirming the anOBJECTIVE: To investigate the analgesic effect of cocktail therapy combined with femoral nerve block in unicompartmental knee arthroplasty. METHODS: One hundred patients who received unicompartmental knee arthroplasty from October 2021 to January 2023 were selected as the study subjects. They were divided into a control group (n=50) and a study group (n=50) using a random number table method. The femoral nerve block was used in the control group, while cocktail therapy combined with femoral nerve block was used in the study group during unicompartmental knee arthroplasty. Postoperative analgesia effect, analgesic frequency of dezocine injection within 2 days after surgery, motion range of affected knee joint, KSS function scores, and the occurrence of postoperative adverse reactions were compared between the two groups. RESULTS AND CONCLUSION: (1) Visual analog scale scores in the study group were lower than those in the control group at 12, 24, and 48 hours after surgery (P < 0.05). (2) The analgesic frequency of dezocine in the study group was less than that in the control group within 2 days after surgery (P < 0.05). (3) The motion range in the study group was higher than that in the control group 1 and 3 days after surgery (P < 0.05). On day 14 after surgery, there was no significant difference in motion range between the two groups (P > 0.05). (4) The knee KSS score in the study group was higher than that in the control group at 2 weeks after surgery (P < 0.05). There was no statistically significant difference in knee KSS scores between the two groups from 6 weeks to 6 months after surgery (P > 0.05). (5) The difference in the occurrence of adverse reactions within 14 days after surgery was not significant between the two groups (P > 0.05). (6) These results show that the use of cocktail therapy combined with femoral nerve block in unicompartmental knee arthroplasty can effectively reduce postoperative pain, improve the analgesic effect, reduce the frequency of analgesic drugs, and improve motion range of the early affected knee joint of patients. [ABSTRACT FROM AUTHOR]

Background: This retrospective study compares the outcomes of unicompartmental medial fixed-bearing knee arthroplasty (mUKA), involving a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component, performed in obese patients with a body mass index (BMI) > 30 with a follow-up of at least 5 years. Methods: The institutional database was mined for primary mUKAs involving an MB or an AP tibial component (MB-UKA and AP-UKA groups, respectively) performed from January 2015 to August 2019. Patient demographics and patient-reported outcome measures (PROMs) were compared and a propensity score matching (PSM) analysis (1:1) using multiple variables was conducted. Results: PSM analysis yielded 37 pairs of obese MB-UKA and AP-UKA patients. At 5 years, the Knee Society Function Score (KSFS) was 75.1 ± 10.6 in MB-UKA and 79.4 ± 9.1 in AP-UKA patients (p = 0.029), and the Oxford Knee Score (OKS) was 38.1 ± 4.4 in MB-UKA and 40.6 ± 5.7 in AP-UKA patients (p = 0.011). Conclusion: At five-year follow-up, in a matched group of obese MB-UKA and AP-UKA patients, the AP-UKA group achieved better KSFSs and OKSs. Both the AP and the MB tibial components were able to bring about a significant improvement of the most widely used PROMs. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate the effect of patellar denervation (PD) on pain, function and ability to kneel after unicompartmental knee arthroplasty (UKA). Methods: Patients with medial knee osteoarthritis who underwent UKA were prospectively selected. Patients were randomly divided into PD and non-PD groups based on whether patellar denervation was performed. Clinical assessment was performed using the Hospital for Special Surgery (HSS) knee score, Kujiala score, visual analogue scale (VAS) and forgotten joint score (FJS-12), as well as postoperative complications were recorded. The patients' postoperative self-perception and actual ability to perform different kneeling positions were assessed in the two groups. Results: UKA patients treated with PD achieved better Kujiala scores and FJS-12 scores, reduced anterior knee pain and improved kneeling ability postoperatively, validating the effectiveness of PD in UKA. Perception and actual performance of kneeling remained mismatched in PD patients, but performance during different kneeling activities was generally better than in non-PD patients. Trial registration: Clinical Trial Registration: ChiCTR1900025669. Conclusion: Patellar denervation can safely and effectively improve patellofemoral joint function, pain and kneeling ability in the early postoperative period after UKA. [ABSTRACT FROM AUTHOR]

Purpose: The impact of gender on the outcomes of unicompartmental knee arthroplasty (UKA) remains a topic of active discussion with limited exploration thus far. The study aims to elucidate the gender effect on clinical outcomes, complications, pre‐ and postoperative radiological outcomes following the implantation of a medial UKA at mid‐term follow‐up in a large section of patients. Methods: This was a single‐centre, retrospective cohort study encompassing patients undergoing medial UKA between 2011 and 2019. The International Knee Society (IKS) Knee and Function score, patient satisfaction, complications, revisions, pre‐ and postoperative radiological outcomes (coronal plane alignment, femoral and tibial component positioning, posterior tibial slope) were evaluated. Survival rate at the time of the last follow‐up was also recorded. Results: Of the 366 knees that met the inclusion criteria, 10 were lost to follow‐up, accounting for a 2.7% loss. Mean follow‐up was 5.2 ± 2 years [2.1–11.3]. Out of the total population, 205 patients were females (57.6%, 205/356) and 151 were males (42.4%, 151/356). Men exhibited superior pre‐ and postoperative IKS function scores (p = 0.017). However, no significant differences were observed between women and men regarding improvements of IKS Knee and Function scores, radiographic outcomes and implant survivorship. Conclusion: At a mean follow‐up of 5 years, this study revealed no significant impact of gender on clinical outcomes and complications in patients undergoing medial UKA. Furthermore, no significant differences were evident in radiographic outcomes, implant positioning and knee phenotype. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Abstract Background Unicompartmental knee arthroplasty (UKA) is a surgical procedure for managing osteoarthritis of one joint compartment, most commonly the medial side. This systematic review investigates the causes of UKA revision. The outcomes of interest were establishing the revision rate, time to revision, and the most common causes of revision in the long- and midterm follow-up. Methods This study was conducted according to the 2020 PRISMA statement. In October 2024, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. All the clinical studies investigating the rate and causes of revision in UKA were accessed. Only studies with a minimum of 10 years of follow-up were considered. Results Data from 56 studies (13,540 patients) were collected. Of them, 65.6% were women. The mean length of the follow-up was 13.1 ± 3.0 years. The mean age of the patients was 65.6 ± 5.6 years, and the mean BMI was 28.5 ± 2.2 kg/m2. Revisions were performed in 8.8% (2641 of 30,140) of implanted UKAs. The mean time to revision was 6.5 ± 2.6 (range, 2.5 to 13.0) years. Conclusion 8.8% (2641 of 30,140) of UKAs were revised at a mean time of 6.5 ± 2.6 years. Level of evidence Level IV, systematic review.

Abstract Background This study systematically reviews recent research comparing clinical outcomes and gait function changes in patients undergoing total knee arthroplasty (TKA) versus unicompartmental knee arthroplasty (UKA). Methods A systematic search of the Web of Science, PubMed, and Embase databases was conducted, covering publications from January 2013 to September 2024, to identify studies evaluating changes in clinical scores and gait parameters in patients undergoing TKA or UKA. Following stringent selection criteria, data were synthesized from studies involving 171 TKA and 148 UKA patients, focusing on reported gait outcomes and aggregating findings for comprehensive analysis. Direct comparisons between TKA and UKA were performed to assess differences in clinical scores and gait parameters, aiming to elucidate the relative efficacy of each surgical approach and provide robust evidence for clinical decision-making. Results Ten studies met the inclusion criteria for post-operative gait outcome comparisons between TKA and UKA, with seven studies also addressing clinical scores. One study reported greater improvement in WOMAC scores for the UKA group at 6 months post-operation (P 0.05). All ten studies assessed gait parameter recovery, with three studies showing no significant differences at 1 year (P > 0.05). However, seven studies identified superior gait recovery in the UKA group across various parameters, including walking speed, step and stride length, single support time, heel strike force, knee joint range of motion, knee flexion angles during different gait phases, peak knee adduction moment, peak tibial internal rotation moment, gait symmetry, and stride length symmetry (P

Introduction: Hypovitaminosis D plays an important role in post-operative bone pain and muscle strength in arthroplasty surgeries. Its role in unicompartmental knee arthroplasty (UKA) has not been elucidated yet. The objective of this study was to determine the impact of hypovitaminosis D and its correction on post-operative bone pain after UKA. Materials and methods: A prospective cohort study involving 240 patients undergoing mobile-bearing medial UKA was conducted. Group A (na=80) received post-operative correction of Vitamin D3 Deficiency (VDD), Group B (nb=80) received pre-operative correction of VDD, while Group C (nc=80) had normal Vitamin D3 levels to begin with (≥30ng/ml). Correction was done by three doses of intramuscular injection of 600,000 IU Arachitol® (Vitamin D3) given at an interval of one week each. All groups were matched for demography and outcome measures. The level of bone pain by checking for tibial shin tenderness quantified by the visual analog scale (VAS) and evaluated pre-operatively, and at 2, 4, 6 and 12 weeks post-operatively. Results: Group B and C showed similar post-operative trends and remained significantly superior to Group A till the 6th-week follow-up. The biostatistical difference between Group A and the other two groups started decreasing after the completion of post-operative correction regime as noticed on the 6th-week follow-up. By 12 weeks post-operatively, all three groups had similar levels of bone pain. Conclusion: Vitamin D3 serves as an important pre-operative investigation in patients undergoing UKA as it is a modifiable risk factor affecting post-operative bone pain. Its correction pre-operatively gives excellent post-operative pain control.

Abstract Purpose This retrospective single-center study aimed to investigate incidence and risk factors influencing tibial periprosthetic fractures (TPF) in Oxford unicompartmental knee arthroplasty (UKA), with a specific focus on tibial component positioning and sizing. Methods A total of 2063 patients with medial UKA using the Oxford® mobile partial knee implant were analyzed between July 2014 and September 2022. Various preoperative and postoperative radiographic parameters determining pre- and postoperative alignment and implant positioning, incidence and characteristics of periprosthetic fractures, and patient demographics were assessed. Statistical analyses, including Mann–Whitney U test and logistic regression, were conducted to identify significant associations and predictors of tibial fractures. Results Of the 1853 cases that were finally included in the study, 19 (1%) patients experienced TPF. The fracture group presented with a significantly shorter relative mediolateral and posteroanterior distance between the keel and cortex [mediolateral: 23.3% (23.2–24.8%) versus 27.1% (25.7–28.3%), p

Abstract Background Periarticular local infiltration analgesia (LIA) has become a widely used method for postoperative pain management after unicompartmental knee arthroplasty (UKA). However, the efficacy of using magnesium sulphate or sodium bicarbonate in LIA cocktails during UKA is not yet clear. The present study aimed to evaluate whether the modified LIA has advantages in pain control and joint function recovery after UKA surgery. Methods Sixty-one patients who underwent UKA were enrolled and randomly assigned to receive periarticular infiltration of a modified cocktail (comprising ropivacaine, epinephrine, dexamethasone, magnesium sulphate, and sodium bicarbonate) or a conventional cocktail (comprising ropivacaine, epinephrine, dexamethasone, ketorolac, and morphine). The outcomes included the consumption of patient-controlled intravenous analgesia (PCIA) medication used for postoperative analgesia, pain score, early joint functional recovery, discharge time, and complication rates. Results In the first 12 h after surgery, the conventional cocktail was not superior to the modified cocktail in terms of visual analogue scale (VAS) scores. However, beginning on the second postoperative day, the analgesic effect was significantly prolonged in the modified group, leading to lower VAS scores and better knee functional recovery. Additionally, patients in the modified group required less pain medication via PCIA, both within the first 24 h and cumulatively up to 48 h after surgery. Both groups had similar rates of complications. Conclusions The present modification of a conventional cocktail significantly prolonged the analgesic effect and reduced pain medication consumption after UKA surgery, which was associated with better functional recovery in the early postoperative days. Trial registration Chinese Clinical Trial Registry, ChiCTR2200060500. 21 March 2023.

Aims: While residual fixed flexion deformity (FFD) in unicompartmental knee arthroplasty (UKA) has been associated with worse functional outcomes, limited evidence exists regarding FFD changes. The objective of this study was to quantify FFD changes in patients with medial unicompartmental knee arthritis undergoing UKA, and investigate any correlation with clinical outcomes. Methods: This study included 136 patients undergoing robotic arm-assisted medial UKA between January 2018 and December 2022. The study included 75 males (55.1%) and 61 (44.9%) females, with a mean age of 67.1 years (45 to 90). Patients were divided into three study groups based on the degree of preoperative FFD: ≤ 5°, 5° to ≤ 10°, and > 10°. Intraoperative optical motion capture technology was used to assess pre- and postoperative FFD. Clinical FFD was measured pre- and postoperatively at six weeks and one year following surgery. Preoperative and one-year postoperative Oxford Knee Scores (OKS) were collected. Results: Overall, the median preoperative navigated (NAV) FFD measured 6.0° (IQR 3.1 to 8), while the median postoperative NAV FFD was 3.0° (IQR 1° to 4.4°), representing a mean correction of 49.2%. The median preoperative clinical FFD was 5° (IQR 0° to 9.75°) for the entire cohort, which decreased to 3.0° (IQR 0° to 5°) and 2° (IQR 0° to 3°) at six weeks and one year postoperatively, respectively. A statistically significant improvement in PROMs compared with baseline was evident in all groups (p < 0.001). Regression analyses showed that participants who experienced a larger FFD correction, showed greater improvement in PROMs (β = 0.609, p = 0.049; 95% CI 0.002 to 1.216). Conclusion: This study found that UKA was associated with an approximately 50% improvement in preoperative FFD across all three examined groups. Participants with greater correction of FFD also demonstrated larger OKS gains. These findings could prove a useful augment to clinical decision-making regarding candidacy for UKA and anticipated improvements in FFD.

Aims: The aim of this study was to determine whether obesity had a detrimental effect on the long-term performance and survival of medial unicompartmental knee arthroplasties (UKAs). Methods: This study reviewed prospectively collected functional outcome scores and revision rates of all medial UKA patients with recorded BMI performed in Christchurch, New Zealand, from January 2011 to September 2021. Patient-reported outcome measures (PROMs) were the primary outcome of this study, with all-cause revision rate analyzed as a secondary outcome. PROMs were taken preoperatively, at six months, one year, five years, and ten years postoperatively. There were 873 patients who had functional scores recorded at five years and 164 patients had scores recorded at ten years. Further sub-group analysis was performed based on the patient’s BMI. Revision data were available through the New Zealand Joint Registry for 2,323 UKAs performed during this time period. Results: Obese patients (BMI > 30 kg/m2) were 3.1 years younger than non-obese patients (BMI < 30 kg/m2) at the time of surgery (mean age of obese patients 65.5 years (SD 9.7) and mean age of non-obese patients 68.6 years (SD 10.1)). Preoperatively, obese patients tended to have significantly lower functional scores than non-obese patients, which continued at five and ten years postoperatively. At these timepoints, obese patients had significantly lower scores for most PROMs measured compared to non-obese patients. However, there was no significant difference in the improvement of any of these scores after surgery between obese and non-obese patients. There was no significant difference in revision rates between obese and non-obese patients at any time. All-cause revision rate for obese patients was 0.73 per 100 observed component years compared to 0.67 in non-obese patients at ten years. There was also no significant difference in the aseptic loosening rate between groups. Conclusion: Our study supports the use of UKAs in obese patients, with similar benefit and survival compared to non-obese patients at ten years.

Abstract Background This retrospective study compares the outcomes of unicompartmental medial fixed-bearing knee arthroplasty (mUKA), involving a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component, performed in obese patients with a body mass index (BMI) > 30 with a follow-up of at least 5 years. Methods The institutional database was mined for primary mUKAs involving an MB or an AP tibial component (MB-UKA and AP-UKA groups, respectively) performed from January 2015 to August 2019. Patient demographics and patient-reported outcome measures (PROMs) were compared and a propensity score matching (PSM) analysis (1:1) using multiple variables was conducted. Results PSM analysis yielded 37 pairs of obese MB-UKA and AP-UKA patients. At 5 years, the Knee Society Function Score (KSFS) was 75.1 ± 10.6 in MB-UKA and 79.4 ± 9.1 in AP-UKA patients (p = 0.029), and the Oxford Knee Score (OKS) was 38.1 ± 4.4 in MB-UKA and 40.6 ± 5.7 in AP-UKA patients (p = 0.011). Conclusion At five-year follow-up, in a matched group of obese MB-UKA and AP-UKA patients, the AP-UKA group achieved better KSFSs and OKSs. Both the AP and the MB tibial components were able to bring about a significant improvement of the most widely used PROMs.

Abstract Objective Knee osteoarthritis (KOA) is usually bilateral. In many patients, the degree of bilateral knee degeneration varies, with one side involving multiple compartments and the other a single compartment degeneration. Therefore, the objective of this study was to compare the early clinical efficacy of simultaneous bilateral and staged total knee arthroplasty (TKA) combined with unicompartmental knee arthroplasty (UKA) in the treatment of bilateral KOA with different degrees. Methods We compared clinical data from 71 simultaneous bilateral TKA/UKA (SB-TKA/UKA) patients with 52 Staged TKA/UKA (Staged-TKA/UKA) patients. Staged-TKA/UKA is defined as TKA on one knee followed by UKA on the other knee. The comparison included Hospital for Special Surgery (HSS) score, range of motion(ROM), complication rate and prosthetic survival rate at the last follow-up between the two groups. Results The follow-up time of SB-TKA/UKA group was (69.08 ± 14.35) months, and that of Staged-TKA/UKA group was (73.25 ± 18.39) months. Staged-KA/UKA group had a shorter hospital stays, less hospitalization costs and shorter operating time (p 0.05). There was no significant difference in complication rate between the two groups (χ2 = 0.56, p = 0.454). For the TKA-side knee joint, there was no significant difference in the prosthetic survival rate (χ2 = 0.05, p = 0.824) and the prosthetic survival curve (χ2 = 0.052, p = 0.82) between the two groups. For UKA-side knee joint, there was no significant difference in prosthetic survival rate (χ2 = 0.08, p = 0.777) and prosthetic survival curve (χ2 = 0.074, p = 0.786) between the two groups. Conclusions Compared to Staged-TKA/UKA, SB-TKA/UKA has the same early clinical efficacy, shorter operating time and hospital stays, less hospitalization costs, and no increased postoperative complications and prosthesis revision rates. Therefore, SB-TKA/UKA may be recommended for patients who can tolerate simultaneous bilateral surgery as assessed before surgery.

Abstract Objective The aim of this study was to investigate the effect of patellar denervation (PD) on pain, function and ability to kneel after unicompartmental knee arthroplasty (UKA). Methods Patients with medial knee osteoarthritis who underwent UKA were prospectively selected. Patients were randomly divided into PD and non-PD groups based on whether patellar denervation was performed. Clinical assessment was performed using the Hospital for Special Surgery (HSS) knee score, Kujiala score, visual analogue scale (VAS) and forgotten joint score (FJS-12), as well as postoperative complications were recorded. The patients’ postoperative self-perception and actual ability to perform different kneeling positions were assessed in the two groups. Results UKA patients treated with PD achieved better Kujiala scores and FJS-12 scores, reduced anterior knee pain and improved kneeling ability postoperatively, validating the effectiveness of PD in UKA. Perception and actual performance of kneeling remained mismatched in PD patients, but performance during different kneeling activities was generally better than in non-PD patients. Trial registration Clinical Trial Registration: ChiCTR1900025669. Conclusion Patellar denervation can safely and effectively improve patellofemoral joint function, pain and kneeling ability in the early postoperative period after UKA.

BACKGROUND: The reasonable implantation range of femoral prosthesis in unicompartmental knee arthroplasty in patients with osteoporosis has not been investigated, and previous studies have often been based on unicompartmental knee arthroplasty models in normal bone, with fewer mechanical studies in models with non-normal bone. Complications after unicompartmental knee arthroplasty have been shown to be highly associated with osteoporosis. OBJECTIVE: To analyze the biomechanical effects of the coronal inclination of the Sled fixed platform femoral prosthesis on unicompartmental knee arthroplasty in patients with osteoporosis and to find the correlation between osteoporosis and mid- and long-term complications after unicompartmental knee arthroplasty. METHODS: Based on the digital imaging technology to obtain the data of the knee joint and prosthesis, a normal bone knee model is then created by using specialized software such as Mimics and Geomagic studio. Based on a validated normal bone knee model, an osteoporotic knee model was created by changing the material parameters. Totally 14 unicompartmental knee arthroplasty finite element models were created using Sled fixed platform femoral prosthesis: standard position (0°), varus and valgus angles: 3°, 6°, 9° in the normal bone and osteoporosis groups. Stress changes on the surface of polyethylene liner, cancellous bone under tibial prosthesis, and cortical bone were calculated and analyzed in all unicompartmental knee arthroplasty models. RESULTS AND CONCLUSION: (1) In the osteoporotic models, the high stress values of the polyethylene liner surface and the cancellous bone under the tibial prosthesis increased with the increase of the tilt angle of the femoral prosthesis, and the high stress values of the cortical bone surface under the tibial prosthesis increased with the increase of the prosthesis valgus angles and decreased with the increase of the varus angles. (2) For the polyethylene liner surface as well as the subcortical bone surface of the tibial prosthesis, the high stress values of the models for each inclination angle in the osteoporosis group were greater than those of the corresponding models in the normal bone group. For the surface of the cancellous bone under the tibial prosthesis, the high stress values of the tilt angle models of the osteoporosis groups were smaller than those of the normal bone groups. (3) Osteoporosis may cause biomechanical abnormalities in the internal structures of the knee after unicondylar replacement, increasing the potential risk of postoperative aseptic loosening of the prosthesis and periprosthetic fractures. Varus and valgus of the femoral prosthesis in the coronal plane should be avoided as much as possible when performing medial unicompartmental knee arthroplasty with a Sled fixation platform in osteoporotic knees. [ABSTRACT FROM AUTHOR]

The utilization of unicompartmental knee arthroplasty (UKA) has remained low when compared to total knee arthroplasty (TKA), possibly due to higher rates of revision and reoperation. This study aimed to quantify surgeon UKA case-volumes and measure the effect of surgeon volume on early revision. We hypothesized that surgeons who have high case volumes would have lower revision rates compared to medium- and low-volume surgeons. Primary UKAs were performed between February 2012 and November 2021, and associated revisions were identified utilizing the Michigan Arthroplasty Registry Collaborative Quality Initiative. Surgeon information, including total cases and annual UKA volume, was collected. Case volume per year was stratified as High (≥ 35 cases per year), Medium (15 to 34 cases per year), and low (< 15 cases per year). There were a total of 15,542 UKAs performed. Of these, 701 (4.5%) were revised, and 412 (58.8%) revisions occurred within 2 years. Of the 287 surgeons who performed an UKA in the registry, 237 (82.6%) were low-volume surgeons, 36 (12.5%) were medium-volume, and 14 (4.9%) were high-volume. High-volume surgeons were more likely to operate on older patients (P < 0.01), Medicare patients (P < 0.01), and patients who had American Society of Anesthesiologists scores of III and IV (P < 0.01). High-volume surgeons had significantly lower 5-year revision rates compared to medium and low-volume surgeons (high: 4.3% (95% confidence interval: 3.7 to 4.9), medium: 5.2% (4.4 to 6.1), low: 7.2% (6.4 to 8.0); P < 0.001). In comparison, the 5-year revision rate for TKA in Michigan was 3.0% (95% confidence interval: 2.9 to 3.1). When UKAs were performed by high-volume surgeons in the state of Michigan, there was better survivorship when compared to low-and medium-volume surgeons. High-volume surgeons were more likely to perform UKA on older patients, Medicare patients, and patients who had American Society of Anesthesiologists scores of III and IV. The revision rate for the high-volume surgeons still exceeded the 5-year revision rate for TKA in Michigan. [ABSTRACT FROM AUTHOR]

Recent expansion in the indications for outpatient total joint arthroplasty has led to debates over patient selection. The purpose of this study was to compare early clinical outcomes and complications of same-day discharge (SDD) hip and knee arthroplasties from a high-volume institution based on the American Society of Anesthesiologists (ASA) physical status classification. Prospectively collected data were reviewed for all SDD primary joint arthroplasties between January 2013 and August 2023. There were 8 surgeons who performed 7,258 cases at hospital outpatient (n = 4,288) or ambulatory surgery centers (n = 2,970). This included 3,239 total hip arthroplasties, 1,503 total knee arthroplasties, and 2,516 unicompartmental knee arthroplasties. The ASA 1 group comprised 506 subjects, compared to 5,005 for ASA 2 and 1,736 for ASA 3. The primary outcomes included emergency department (ED) visits, readmissions, complications, and revisions within 24 hours and 90 days of surgery. The ASA 3 group was older (ASA 1 = 55 versus ASA 2 = 63 versus ASA 3 = 66 years; P <.01) and had a higher body mass index (ASA 1 = 25.4 versus ASA 2 = 28.5 versus ASA 3 = 32.7; P <.01). There were no differences between ASA groups in joint-related ED visits, readmissions, and complications within 24 h and 90 days of surgery (P >.05). Subjects in the ASA 3 group experienced greater 90-day revisions compared to the other groups (ASA 1 = 1 of 506, 0.2% versus ASA 2 = 15 of 5,005, 0.3% versus ASA 3 = 15 of 1,736, 0.9%; P =.01). Regarding systemic events, ASA 1 subjects experienced significantly greater 24-hour complications (8 of 506, 1.6%) and ED visits (5 of 506, 1.0%), and the ASA 3 subjects had a higher incidence of 90-day readmissions (19 of 1,736, 1.1%) compared to the other groups (P <.05). Within 24 hours of discharge, urinary retention and syncope were the most frequent complications that required additional health care utilization. Medically optimized patients categorized as ASA 3 can safely undergo SDD hip and knee arthroplasty without increased risk of 24-hour or 90-day complications. Patient preference for outpatient care, reliable social support, and independent functional status are imperative for a successful outpatient program. [ABSTRACT FROM AUTHOR]

Abstract Background Aims of this study were to compare the functional and radiographic results, perioperative complication after lateral unicompartmental knee arthroplasty (LUKA) with total knee arthroplasty (TKA) and the legacy constrained condylar knee (LCCK) arthroplasty for the treatment of lateral compartmental knee osteoarthritis (LCKOA), and to provide a basis for the treatment of LCKOA. Methods From January 2021 to January 2024, analyzed retrospectively clinical data of 74 patients with LCKOA treated with LUKA, TKA and LCCK arthroplasty. According to the operation plan, the patients were divided into three groups: LUKA group (23 cases), TKA group (23 cases) and LCCK group (28 cases). The changes of hip-knee-ankle (HKA) angle of the affected knee before and after operation were measured. All patients were assessed using the operation time, blood loss during operation, incision length, visual analogue scale (VAS) score before operation and after operation, Hospital for Special Surgery score (HSS), Oxford Knee Score (OKS), range of motion (ROM). Results All 74 patients were followed up for (2.38 ± 0.33) years. The operation time, blood loss during operation, incision length and VAS score after operation in the LUKA group were significantly less than those in the TKA group and LCCK group (P 0.05). Conclusion LUKA, TKA and LCCK arthroplasty have good clinical effect in the treatment of LCKOA; Compared with TKA and LCCK arthroplasty, LUKA has the advantages of less trauma, less bleeding, less pain and quick recovery. The short-term effect is satisfactory, and the long-term effect remains to be observed.

Abstract Background Unicompartmental knee arthroplasty (UKA) has been proved to be a successful treatment for osteoarthritis patients. However, the stress shielding caused by mismatch in mechanical properties between human bones and artificial implants remains as a challenging issue. This study aimed to properly design a bionic porous tibial implant and evaluate its biomechanical effect in reconstructing stress transfer pathway after UKA surgery. Methods Voronoi structures with different strut sizes and porosities were designed and manufactured with Ti6Al4V through additive manufacturing and subjected to quasi-static compression tests. The Gibson-Ashby model was used to relate mechanical properties with design parameters. Subsequently, finite element models were developed for porous UKA, conventional UKA, and native knee to evaluate the biomechanical effect of tibial implant with designed structures during the stance phase. Results The internal stress distribution on the tibia plateau in the medial compartment of the porous UKA knee was found to closely resemble that of the native knee. Furthermore, the mean stress values in the medial regions of the tibial plateau of the porous UKA knee were at least 44.7% higher than that of the conventional UKA knee for all subjects during the most loading conditions. The strain shielding reduction effect of the porous UKA knee model was significant under the implant and near the load contact sites. For subject 1 to 3, the average percentages of nodes in bone preserving and building region (strain values range from 400 to 3000 μm/m) of the porous UKA knee model, ranging from 68.7 to 80.5%, were higher than that of the conventional UKA knee model, ranging from 61.6 to 68.6%. Conclusions The comparison results indicated that the tibial implant with designed Voronoi structure offered better biomechanical functionality on the tibial plateau after UKA. Additionally, the model and associated analysis provide a well-defined design process and dependable selection criteria for design parameters of UKA implants with Voronoi structures.

The distal femur is one of the most common sites for primary bone tumors. As the tumor progresses and bone destruction worsens, it can severely affect knee function and even pose a threat to life. In cases where only one condyle is affected and requires resection, preserving the healthy contralateral condyle can substantially enhance the biomechanics of the knee. Furthermore, preserving bone stock may enable future salvage procedures in the event of initial surgery failure, be it from fractures or osteoarthritis. Distal femoral unicondyle resection can offer better functional outcomes in select cases. However, it is essential to prioritize oncological safety with adequate margins over short‐term knee function. Currently, the primary methods for reconstruction after the excision of a unicondylar tumor include allograft transplantation (bi‐ or uni‐condylar) and prosthetic or allograft‐prosthesis composite replacement (APC). However, there is currently some controversy regarding the optimal surgical reconstruction method, and a consensus within the academic community has yet to be reached. Moreover, due to the rarity of bone tumors, extensive clinical data from a single center is limited. Current studies are mainly retrospective and single‐center, lacking sufficient cases and follow‐up duration. This article reviews surgical reconstruction after solitary condylar excision in distal femoral tumors. It summarizes, compares, and analyzes mainstream reconstruction methods, exploring their technical details and clinical outcomes to highlight their potential in bone oncology.

Background Mobile bearing fracture is a rare long‐term complication of unicompartmental knee arthroplasty (UKA), and relevant reports are sparse. Hence, its treatment options need further exploration. Case Presentation This study presents the case of fracture of a polyethylene insert that occurred 12 years after mobile bearing medial UKA in a 75‐year‐old overweight woman who then underwent surgical intervention at our institution. However, we encountered significant challenges in removing the fragments from the broken bearing, resulting in retention of the remaining one‐third of the fragment. We solved this problem by replacing the fractured insert with thicker mobile bearing. During the 1‐month postoperative follow‐up, the patient achieved good range of motion and excellent satisfaction, with no reported complications and a Knee Society Score of 90. Additionally, we reviewed the literature on the treatment for mobile bearing fractures after UKA. Conclusions Bearing fracture is a rare cause of failure of mobile bearing UKA. This case highlights the challenges of UKA fracture bearing retrieval and underscores that mobile bearing replacement can be an effective intervention. The case we report shows that when removal of a residual meniscal bearing in a posterior dislocation is difficult to achieve, compromise may be an appropriate option because it does not cause additional complaints to the patient. This case emphasizes the importance of the surgeon having a thorough preoperative understanding of the location and potential pitfalls of fracture fragments in such situations.

Abstract Objective The practice of simultaneous bilateral unicompartmental knee arthroplasty (SBUKA) remains a topic of debate, particularly in patients with obesity. Thus, the purpose of this study was to assess the impact of body mass index (BMI) on the 30-day complication rate and the survival rate of the implant following SBUKA. Methods We retrospectively examined the clinical records of 245 patients (490 knees) who underwent SBUKA at the Affiliated Hospital of Qingdao University and the Third Hospital of Hebei Medical University between January 2010 and December 2020. Patients were categorised based on their BMI at the time of surgery into four groups: normal weight (BMI 18.5 to 22.9 kg/m2), overweight (BMI 23.0 to 24.9 kg/m2), obese (BMI 25.0 to 29.9 kg/m2), and severely obese (BMI ≥30 kg/m2). Variables such as length of hospital stay, duration of surgery, and costs of hospitalisation were compared across all groups. Additionally, we recorded the 30-day postoperative complication rate and the time from surgery to any required revision. The Kaplan-Meier survival analysis was employed to evaluate and compare the implant survival rates. Results The follow-up period for the 245 patients ranged from 39 to 114 months, with an average of 77.05±18.71 months. The incidence of complications within 30 days post-surgery did not significantly differ across the groups (χ2 = 1.102, p = 0.777). The implant survival rates from the lowest to the highest BMI groups were 97.14%, 93.9%, 94.44%, and 96.43%, respectively. Both the rate of implant revision (χ2 =1.612, p = 0.657) and the survival curves of the implants (p = 0.639) showed no statistically significant differences among the groups. Conclusions BMI did not influence the 30-day complication rate nor the survival rate of implants following SBUKA, suggesting that SBUKA should not be contraindicated based on BMI alone.

Objective How to minimize postoperative pain following knee replacement surgery has been a great challenge. This study was performed to evaluate the effect of applying a topical nonsteroidal anti‐inflammatory drug (NSAID) lateral to the incision for postoperative pain following unicompartmental knee arthroplasty (UKA). Methods The randomized controlled trial enrolled 100 patients from August 2023 to January 2024. One hundred patients who underwent UKA were randomized into two groups. The intervention group received a topical NSAID lateral to the incision postoperatively, and the control group received a placebo lateral to the incision postoperatively. The primary outcome measures were the amount of opioid consumption and the visual analogue scale (VAS) score (12, 24, 36, 48, and 72 h after operation) for pain. The secondary outcome measures were the American Knee Society Score (AKSS, preoperation and 1‐month follow‐up after operation), the time of first analgesic demand, side effects of opioids, operation time, postoperative stay, surgery‐related complications, and postoperative incision healing grade. Independent sample t test and paired sample t test were used to compare continuous data. Chi‐square test and Fisher's precision probability tests were used to analyze the categorical data. Results Ninety‐eight patients (intervention group, 48 patients; control group, 50 patients) were analyzed. Opioid consumption was significantly lower in the intervention group than in the control group during the first 12 h, 12 to 24 h, and 24 to 48 h postoperatively (p

Background: Aims of this study were to compare the functional and radiographic results, perioperative complication after lateral unicompartmental knee arthroplasty (LUKA) with total knee arthroplasty (TKA) and the legacy constrained condylar knee (LCCK) arthroplasty for the treatment of lateral compartmental knee osteoarthritis (LCKOA), and to provide a basis for the treatment of LCKOA. Methods: From January 2021 to January 2024, analyzed retrospectively clinical data of 74 patients with LCKOA treated with LUKA, TKA and LCCK arthroplasty. According to the operation plan, the patients were divided into three groups: LUKA group (23 cases), TKA group (23 cases) and LCCK group (28 cases). The changes of hip-knee-ankle (HKA) angle of the affected knee before and after operation were measured. All patients were assessed using the operation time, blood loss during operation, incision length, visual analogue scale (VAS) score before operation and after operation, Hospital for Special Surgery score (HSS), Oxford Knee Score (OKS), range of motion (ROM). Results: All 74 patients were followed up for (2.38 ± 0.33) years. The operation time, blood loss during operation, incision length and VAS score after operation in the LUKA group were significantly less than those in the TKA group and LCCK group (P < 0.05); HKA valgus angle, ROM, HSS score and OKS score of the three groups after operation were significantly better than those before operation (P < 0.05); There was no significant difference among the three groups in HSS score and OKS score (P > 0.05). Conclusion: LUKA, TKA and LCCK arthroplasty have good clinical effect in the treatment of LCKOA; Compared with TKA and LCCK arthroplasty, LUKA has the advantages of less trauma, less bleeding, less pain and quick recovery. The short-term effect is satisfactory, and the long-term effect remains to be observed. [ABSTRACT FROM AUTHOR]

Objective: This meta-analysis sought to compare the efficacy of cemented versus cementless Oxford unicompartmental knee arthroplasty(UKA) for the treatment of medial knee osteoarthritis. Methods: A comprehensive search of the following databases was conducted: Pubmed, The Cochrane Library, China National Knowledge Infrastructure (CNKI), Embase, the Web of Science, and MEDLINE. The objective was to identify literature comparing cemented versus cementless Oxford unicompartmental knee arthroplasty for the treatment of medial knee osteoarthritis. Duplicate literature, low-quality literature, literature with incompatible observations, and literature for which the full text was not available were excluded. Two independent researchers employed the Cochrane Risk Assessment Tool and the Newcastle-Ottawa Scale (NOS) to evaluate the quality of the included literature. The data then were extracted and subsequently meta-analyzed using RevMan 5.4. Results: A total of 12 papers were included in the analysis, encompassing a cumulative of 2558 cumulative cases. Of these, 1258 were cemented and 1300 were cementless. A meta-analysis was conducted to compare the outcomes of cemented versus cementless Oxford UKA. The Oxford UKA group exhibited a significantly longer surgery time than the cementless Oxford UKA group [mean difference (MD) = 9.91, 95% confidence interval (CI) (7.64,12.17)]. Additionally, the cemented Oxford UKA group demonstrated a significantly lower knee OKS score compared to the cementless Oxford UKA group. The mean difference (MD) was − 1.58 (95% CI: -2.30, -0.86), indicating a significantly lower score for the cemented Oxford UKA group. Similarly, the mean difference (MD) was − 1.8 for the knee KSS clinical score, indicating a significantly lower score for the cemented Oxford UKA group. The results demonstrated that the knee KSS functional score was significantly lower in the cemented Oxford UKA group than in the cementless Oxford UKA group [MD=-1.72, 95% CI (-3.26, -0.37)]. 95% CI (-3.27,-0.17)], the cemented Oxford UKA group exhibited a significantly higher incidence of radiolucent lines around the prosthesis than the cementless Oxford UKA group [ratio of ratios (OR) = 3.62, 95% CI (1.08,12.13)]. The revision rate was significantly higher in the cemented Oxford UKA group than in the cementless Oxford UKA group [OR = 2.22, 95% CI (1.40,3.53)]. However, no significant difference was observed between the two groups in terms of reoperation rate, five-year prosthesis survival rate, and complication rate. Conclusions: The findings indicated that, in comparison to cemented Oxford UKA, cementless Oxford UKA resulted in a reduction in surgical time, an improvement in knee OKS score, KSS clinical score, and KSS functional score, and a decrease in the incidence of periprosthetic radiolucent lines and the rate of revisions. [ABSTRACT FROM AUTHOR]

Introduction: Lateral unicompartmental knee arthroplasties (LUKA) account for only < 1% of all knee arthroplasties and for only 5–10% of all unicompartmental knee replacements. This means that there is less published literature on these procedures and that the surgeon's experience with them is smaller than with medial UKA. The aim of this study was to analyze the survival and the clinical-functional outcomes of LUKA according to the type of bearing surface (all-polyethylene versus metal-backed) used. Materials and methods: This was a retrospective study including 42 LUKAs operated between 2009 and 2021. Two fixed polyethylene-bearing models were used: the all-polyethylene ACCURIS knee (38%) and the metal-backed Triathlon PKR system (62%). Demographic parameters, knee range of motion (ROM), tibiofemoral alignment, implant survival (as estimated with the Kaplan–Meier curve), and clinical-functional outcomes (as measured with the Knee Society Score) were analyzed. Results: Average patient age was 65.5 (range, 36–87) years and mean follow-up was 8.2 (range, 2.1–12.8) years. Thirty LUKAs (71.4%) were implanted in women. The main reason for performing a LUKA was osteoarthritis (88.1%). No patient developed post-surgical complications or had to be re-operated. Overall LUKA survival was 100% at 1-year and 5-year's follow-up. Knee Society Score, knee ROM and tibiofemoral alignment all improved significantly post-surgery (p < 0.001). The clinical Knee Society Score increased from 46.5 ± 14.5 pre-surgery to 93.5 ± 10.3 post-surgery, the functional Knee Society Score increased from 48.1 ± 13.5 pre-surgery to 94.6 ± 9.3 post-surgery, maximum flexion increased from 108.5 ± 8.7 degrees pre-surgery to 121 ± 8.9 degrees post-surgery and tibiofemoral alignment was corrected from 13.1 ± 1.74 degrees pre-surgery to 5.7 ± 0.8 degrees post-surgery. There were no statistically significant clinical-functional improvement or knee ROM differences between groups (p < 0.05, respectively). Conclusion: LUKA is a valid and definitive option for patients with lateral tibiofemoral osteoarthritis, with a survival rate of > 95% at 5-years follow-up. Clinical-functional outcomes are the same, irrespective of the tibial component used. [ABSTRACT FROM AUTHOR]

Introduction: A significant portion of knee osteoarthritis is diagnosed in patients under the age of 55, where greater activity demands make total knee arthroplasty less desirable. High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are useful alternatives, but there is little understanding of which procedure is advantageous. Hence, this study examines the utilization, complication, and reoperation rates among the HTO vs. UKA in young patients with primary osteoarthritis. Methods: A retrospective review of the National Surgical Quality Improvement Program was performed to identify 2318 patients < 55 years of age who received either a HTO or UKA for primary osteoarthritis between 2011 and 2021. Bivariate analyses compared preoperative and intraoperative characteristics among each procedure. Then, multivariate analyses examined if either procedure was associated with worse 30-day postoperative complications or need for reoperation, independent of the statistically significant pre- and intraoperative disparities. Results: UKAs were performed 14.2 times more commonly than HTOs, and the patients selected for HTO were more likely to be younger, have a lower BMI, have the healthiest ASA Class score, and less likely to have hypertension requiring medication (p < 0.001). HTOs took 17.5% longer to perform and had a longer average length of stay (p < 0.001), while UKAs were more likely to be performed out-patient (p < 0.001). HTOs also had higher rates of serious complications (p = 0.02), overall complications (p = 0.004), and need for reoperation (p = 0.004). Multivariate modelling demonstrated that procedure type was not a predictor of serious complications, but the use of HTO was significantly associated with any complications (odds ratio = 3.63, p = 0.001) and need for reoperation (3.21, p = 0.029). Conclusion: Although healthier patients were selected for HTOs, UKAs were found to have a lower risk of complications and immediate reoperation. Additionally, UKAs had the advantage of lower operative burden, shorter length of stay, and a higher efficacy in outpatient settings. [ABSTRACT FROM AUTHOR]

Introduction: Surgical options for patients with unicompartmental knee osteoarthritis include high tibial osteotomy (HTO) or unicompartmental knee arthroplasty (UKA). When managing younger patients with a higher chance of further surgery, the outcome of any subsequent conversion to total knee arthroplasty (TKA) also needs to be considered. The aim of this study was to compare implant survivorship and patient-reported outcomes for patients undergoing TKA after previous HTO or UKA, with comparisons for age, gender and comorbidities. Methods: Revision risk and 6-month Oxford Knee Scores (OKS) from the New Zealand Joint Registry were compared for patients who underwent TKA after HTO (HTO-TKA; n = 1556) or UKA (UKA-TKA; n = 965) between 1999 and 2019, with a comparison group of primary TKA (n = 110,948). Mean follow-up was 8.2 years. Results: Adjusted revision risk was similar for HTO-TKA and UKA-TKA groups (hazard ratio (HR) 1.04, p = 0.84); and risk for both groups were higher than primary TKA (HTO-TKA HR 1.45, p = 0.002; UKA-TKA HR 1.51, p = 0.01). Overall adjusted mean OKS at 6 months for HTO-TKA (36.2) was similar to primary TKA (36.8, p = 0.23); and both were higher than UKA-TKA (34.2, p < 0.001). For the youngest patient group (< 55 years), revision rates of UKA-TKA were two-fold higher than HTO-TKA (2.8 vs. 1.3 per 100 component yrs, p < 0.03). HTO-TKA had better OKS (37.5 vs. 34.1, p < 0.0001) for males. Mean OKS for UKA-TKA was lower than HTO-TKA for patients with ASA 1–2 (35.6 vs. 37.5, p < 0.01). Conclusion: The findings from this study suggest that revision rate following TKA after HTO and UKA are similar. However, TKA after HTO have superior functional outcomes compared with TKA after UKA and are comparable to functional outcomes post primary TKA. The results support the use of HTO for young, male and less co-morbid patients. [ABSTRACT FROM AUTHOR]

Introduction: Unicompartmental Knee Arthroplasty (UKA) and High Tibial Osteotomy (HTO) are two valid options in the treatment of Anteromedial Osteoarthritis (AMOA) of the knee with UKA being mainly performed in cases of Intraarticular deformity (IA) and HTO in cases of Extraarticular deformity (EA). The exact unintentional effect of UKA on EA deformity and HTO on IA deformity is still not well understood. The aim of this study was to assess this unintentional effect of UKA on EA and HTO on IA deformities respectively. Materials and methods: This a single-center retrospective study in which 50 patients who underwent UKA and 50 patients who underwent medial opening wedge HTO (MWOHTO) for the treatment of AMOA were included. Overall, 35 males and 15 females underwent HTO with a mean age of 44.3 ± 11.2 years while the mean age of the UKA group was 71.8 ± 7.9 years in 23 males and 27 females. The radiological effect of UKA and HTO on each of the following angles: Hip-Knee-Ankle angle (HKA), Medial Proximal Tibial Angle (MPTA), mechanical Lateral Distal Femoral Angle (mLDFA) and Joint Line Convergence Angle (JLCA) on long film radiographs both pre- and postoperatively was measured. The postoperative values were compared to the preoperative values to detect the expected and unintended effects of each technique on IA and EA deformities. Results: In the HTO group, the MPTA has changed significantly as expected from 83.1 ± 4.5 preoperatively to 88.9 ± 3.9 postoperatively (p value < 0.001) correcting the existing preoperative EA varus without overcorrection. Similarly in the UKA group, the JLCA has also changed significantly as expected to correct the IA varus from 3.8 ± 1.7 preoperatively to 0.9 ± 1 postoperatively (p value < 0.001). On the other hand, the JLCA was unintentionally changed in the HTO group from 2.6 ± 2.1 preoperatively to 1.6 ± 2.4 postoperatively (p value = 0.03) partly correcting the IA varus deformity. Similarly, the MPTA showed a significant change that occurred inadvertently in the UKA group from 84.8 ± 2.1 to 86.3 ± 1.6 postoperatively (p value < 0.001). This unintentional increase in the MPTA also partly corrected the preexisting EA varus deformity. The mLDFA did not show a significant change neither in the HTO group (p value = 0.96) nor in the UKA group (p value = 0.94). Conclusion: In addition to intraarticular varus correction, UKA can partly correct the extraarticular varus deformity in AMOA even when resurfacing is exclusively attempted. Additionally, intraarticular deformity can be also partially managed by HTO along with the extraarticular varus correction even without performing overcorrection. [ABSTRACT FROM AUTHOR]

Introduction: This study was aimed to assess the return to sport (RTS) rate in patients who underwent CT-based robotic-assisted unicompartmental knee arthroplasty (RA-UKA) and to evaluate the clinical performance and the assocition between patients' sport activity levels and Patient Reported Outcome Measures after surgery. Materials and methods: This retrospective study included 218 patients undergoing medial RA-UKA with fixed-bearing implants, performed at a single center between 2014 and 2019. Patients were allocated into two groups based on sport's practice and were administered the University of California, Los Angeles (UCLA) activity scale, Forgotten Joint Score-12 (FJS-12), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and the 5-Level Likert Scale. Results: A total of 136 patients were included for assessment. The overall RTS rate after surgery was 93.1%. Six subjects who did not practice sport preoperatively, were able to start sport activities after surgery and all patients performing sports preoperatively, returned to same activity level. The mean UCLA and FJS-12 scores in the group of patients practicing sports were significantly higher than in the no-sport group (p < 0.001 and p < 0.05, respectively). Patients who practiced sports were more likely to attain higher FJS-12 and UCLA scores than those who were not performing physical activity. Conclusions: Patients undergoing RA-UKA showed a 93.1% RTS rate after surgery. Differences were detected in terms of postoperative UCLA and FJS-12 scores between patients who performed and who did not practice sport activities after surgery. High levels of postoperative UCLA scores were associated with higher KOOS-JR and patients' satisfaction. [ABSTRACT FROM AUTHOR]

Background: There is a lack of literature reporting on long‐term outcomes following robotic‐arm‐assisted lateral unicompartmental knee arthroplasty (UKA). This study assessed the long‐term survivorship, patient‐reported satisfaction and pain scores following robotic‐arm‐assisted lateral UKA for lateral compartment osteoarthritis (OA). Methods: A single surgeon's database was reviewed to identify all patients who underwent robotic‐arm‐assisted lateral UKA with a cemented, fixed‐bearing prosthesis prior to May 2015. Patients were contacted to determine implant survivorship, satisfaction and pain. Kaplan–Meier models were applied to analyse survival. Results: A total of 77 knees (70 patients) with a mean follow‐up of 10.2 ± 1.5 years (range: 8.1–13.3) were included. Five knees were revised, corresponding to a 10‐year survivorship of 96.1% and estimated survival time of 12.7 ± 0.3 years (95% confidence interval: 12.2–13.2) with all‐cause revision as the endpoint. Unexplained pain (40.0%) and progression of OA (40.0%) in contralateral compartments were the most reported reasons for revision. Among patients without revision, 94.4% were either satisfied or very satisfied with their lateral UKA and the average pain score was 1.1. Conclusion: Robotic‐arm‐assisted lateral UKA led to high implant survivorship and patient satisfaction, and low pain scores at long‐term follow‐up. Progression of OA in contralateral compartments and unexplained pain were the most frequent reasons for revision. These findings support the continued use of robotic‐arm‐assisted lateral UKA for lateral compartment OA; however, its clinical value over conventional techniques remains to be established in prospective comparative studies. Level of Evidence: Therapeutic Level IV. [ABSTRACT FROM AUTHOR]

Background and Objectives: The ten-year survivorship of unicompartmental knee arthroplasty (UKA) is up to 96%, varying from implants and hospitals; however, most of registry studies do not distinguish between metal-back (MB) tibial implants and all-polyethylene (AP) tibial implants. The aim of the present retrospective clinical study was to analyze the clinical outcomes and survivorship of medial and lateral UKA with a newly designed all-polyethylene tibial plateau at short-term follow-up. Materials and Methods: A retrospective analysis of prospectively collected consecutive patients who underwent medial or lateral UKA with AP tibial plateau was conducted, with a minimum follow-up of 1 year. Primary outcomes were clinical score (VAS, OKS, and KOOS) variations from baseline up to the latest follow-up. Secondary outcomes were Likert scale variations from baseline to the follow-up, evaluation of the influence of demographic factors (age and BMI) at the time of surgery on the clinical outcomes, and evaluation of revision rate up to the last follow-up. Results: The final study population included 99 knees. The mean VAS score for the medial group significantly decreased from 7.61 ± 1.65 (pre-intervention) to 2.74 ± 2.26 (post-intervention). Similar improvements were registered for the OKS as well, for both the medial group (from 22.5 ± 12.6 to 36.6 ± 10.6, with a delta of 14.11 (10.05 to 18.17)) and the lateral group (from 22.6 ± 12.6 to 36.9 ± 11.8, with a delta of 14.24 (8.65 to 19.83)). Moreover, all the KOOS subscales reported an amelioration, both in medial UKA and lateral UKA. Furthermore, a logistic regression of delta VAS was performed in relation to the other clinical questionnaires and the demographic factors. For both medial and lateral UKAs, no statistically significant correlation was found between the VAS scale regression and the demographic factors. The survival rate free from any revision of the cohort at the latest follow-up was 96.32%. Conclusions: All-polyethylene tibial component in unicompartmental knee arthroplasty demonstrates significant improvements in clinical scores and a low failure rate at short-term follow-up. [ABSTRACT FROM AUTHOR]

Robotic-arm-assisted unicompartmental knee arthroplasty (UKA) is an excellent solution for patients suffering from single-compartment knee arthritis. While outcomes tend to be favorable for UKAs, revision operations, commonly due to component malpositioning and malalignment resulting in accelerated wear, are a major concern. Intraoperative technologies, such as robotic assistance, can help better ensure that implants are positioned based on a patient's specific anatomy and mechanical physiology. However, long-term survivorship and patient-reported satisfaction with robotic-assisted UKAs are limited. Therefore, the purpose of this study was to assess the 10-year outcomes of patients who underwent robotic-arm-assisted unicompartmental knee arthroplasty. Specifically, we evaluated: 1) 10-year survivorships; 2) patient satisfaction scores; and 3) re-operations. From a single surgeon and single institution, 185 patients who had a mean age of 65 years (range, 39 to 92) and a mean body mass index of 31.6 (range, 22.4 to 39) at a mean of 10 years follow-up were evaluated (range, 9 to 11). For all patients, the same robotic-assistive device was utilized intraoperatively, and all patients underwent standardized physical therapy and received standardized pain control management. Then 10-year survivorships with Kaplan-Meir curves, patient satisfaction evaluations with a 5-point Likert scale, and re-operations were assessed as primary outcomes. Overall implant survivorship was 99%, with only two patients requiring revision surgery. There was one patient who was converted to a total knee arthroplasty, while the other patient underwent polyethylene exchange at 5 weeks for an acute infection with successful implant retention. Overall, 97% of the patients were satisfied with their postoperative outcomes, with 81% of patients reporting being very satisfied. There were two other patients who required arthroscopic intervention: one to remove a cement loose body, the other to remove adhered scar from the fat pad and the anterior cruciate ligament. This study is one of the first to provide longer-term (mean 10-year) survivorship and patient-reported satisfaction outcomes for robotic-assisted UKA patients. These data show strong support for utilizing this surgical technique, as nearly all patients maintained their original prostheses and reported being satisfied after a mean of 10 years. Therefore, based on these results, we recommend the use of robotic assistance when performing UKAs. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous studies on the effects of valgus and varus angles of tibial component on short-term postoperative outcomes after mobile bearing unicompartmental knee arthroplasty have been reported in and outside China. However, there are few reports on the effect of the valgus and varus angles of tibial component on short-term postoperative outcomes after fixed bearing unicompartmental knee arthroplasty. OBJECTIVE: To investigate the effect of valgus and varus angles of tibial component on short-term clinical outcomes in patients with medial knee osteoarthritis undergoing fixed bearing unicompartmental knee arthroplasty. METHODS: 120 patients (122 knees) who underwent fixed bearing unicompartmental knee arthroplasty for medial knee osteoarthritis in Department of Orthopedic Surgery, Affiliated Hospital of Xuzhou Medical University from August 2020 to January 2023 were selected as the study subjects. Two physicians measured the varus angle of femoral prosthesis, valgus and varus angles of tibial prosthesis, flexion and extension angles of femoral prosthesis, and posterior inclination angle of tibial prosthesis after unicompartmental knee arthroplasty based on postoperative X-ray. After excluding the influence of the other three angles, the measurement results of the tibial component varus angle were divided into three groups: <-2°,-2° to 2°, >2°, which were denoted as groups 1, 2, and 3, respectively. The range of knee motion, the hospital for special surgery knee score, the American knee society score, and forgotten joint score were recorded and compared before and after the operation. RESULTS AND CONCLUSION: (1) A total of 120 patients (122 knees) were enrolled in this study. They were divided into three groups according to the size of the valgus and varus angles of the tibial prosthesis after operation: 37 patients in the first group, 60 patients in the second group, and 23 patients in the third group. There was no significant difference between the three groups in terms of baseline information such as age, gender, and side of surgery (P > 0.05). (2) Patients were followed up for 3-30 months after arthroplasty. (3) The hospital for special surgery knee score of the second group was higher than that of the first group (P=0.015) and the third group (P=0.012). The American knee society score of the second group was significantly higher than that of the first group (P=0.014) and the third group (P < 0.001). The forgotten joint score of the second group was higher than that of the first group (P=0.033) and the third group (P=0.016). (4) After fixed bearing unicompartmental knee arthroplasty, when the valgus angle of tibial prosthesis was -2° to 2°, which can achieve better shortterm clinical results, the degree of prosthesis self-realization is higher [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) has been proved to be a successful treatment for osteoarthritis patients. However, the stress shielding caused by mismatch in mechanical properties between human bones and artificial implants remains as a challenging issue. This study aimed to properly design a bionic porous tibial implant and evaluate its biomechanical effect in reconstructing stress transfer pathway after UKA surgery. Methods: Voronoi structures with different strut sizes and porosities were designed and manufactured with Ti6Al4V through additive manufacturing and subjected to quasi-static compression tests. The Gibson-Ashby model was used to relate mechanical properties with design parameters. Subsequently, finite element models were developed for porous UKA, conventional UKA, and native knee to evaluate the biomechanical effect of tibial implant with designed structures during the stance phase. Results: The internal stress distribution on the tibia plateau in the medial compartment of the porous UKA knee was found to closely resemble that of the native knee. Furthermore, the mean stress values in the medial regions of the tibial plateau of the porous UKA knee were at least 44.7% higher than that of the conventional UKA knee for all subjects during the most loading conditions. The strain shielding reduction effect of the porous UKA knee model was significant under the implant and near the load contact sites. For subject 1 to 3, the average percentages of nodes in bone preserving and building region (strain values range from 400 to 3000 μm/m) of the porous UKA knee model, ranging from 68.7 to 80.5%, were higher than that of the conventional UKA knee model, ranging from 61.6 to 68.6%. Conclusions: The comparison results indicated that the tibial implant with designed Voronoi structure offered better biomechanical functionality on the tibial plateau after UKA. Additionally, the model and associated analysis provide a well-defined design process and dependable selection criteria for design parameters of UKA implants with Voronoi structures. [ABSTRACT FROM AUTHOR]

This article presents a series of case studies on the rare complication of meniscal bearing fractures after unicompartmental knee arthroplasty (UKA). The authors describe the symptoms, radiographic findings, and surgical interventions of six patients who experienced this complication. They suggest that a 3 mm bearing thickness may be a risk factor for fracture, but the role of BMI is inconclusive. The authors emphasize the importance of considering meniscal bearing fracture as a potential diagnosis in patients with sudden symptoms after UKA and recommend a systematic diagnostic approach to avoid overlooking this complication. [Extracted from the article]

Purpose: This systematic review and meta-analysis aimed to evaluate the safety of outpatient and inpatient Unicompartmental Knee Arthroplasty (UKA) based on the incidence of adverse events. Method: A systematic search of the literature was performed in October 2022 on PubMed, Web of Science, Cochrane library, and Embase. The Meta package for R was used to perform the meta-analysis. Result: Five studies with a total of 26,301 patients were included. 5813 patients (22.1%) were treated with outpatient UKA, and 20,488 patients (77.9%) were treated with inpatient UKA. There were no statistically significant differences in the incidence of total complications (RR = 1.36, 95% CI = 0.64–2.89, Z = 0.79, P = 0.43), readmission (RR = 1.02, 95% CI = 0.40–2.60, Z = 0.05, P = 0.96), and venous thrombosis (RR = 1.43, 95% CI = 0.96–2.11, Z = 1.78, P = 0.08). Incidence rates were lower in outpatient UKA regarding urinary tract infection (RR = 1.48, 95% CI = 1.07–2.04, Z = 2.40, P = 0.02), pulmonary embolus (RR = 7.48, 95% CI = 1.80–31.17, Z = 2.76, P < 0.01), and transfusion (RR = 2.77, 95% CI = 1.63–4.71, Z = 3.78, P < 0.01). Conclusion: In summary, outpatient UKA shows lower incidences of hospital-acquired complications such urinary tract infection, pulmonary embolus, and transfusion. It's worth noting that the incidences of total complications, readmission, and venous thrombosis in outpatient UKA were not higher than the incidences of inpatient UKA, suggestting that outpatient UKA can be considered a safe alternative to inpatient UKA. [ABSTRACT FROM AUTHOR]

Purpose: Unexpected positive cultures are defined as a single positive culture in intraoperative samples taken during revision surgery after prosthetic joint infection was preoperatively ruled out. This study aims to determine the prevalence of unexpected positive cultures (UPC) in revision total knee arthroplasty (TKA) after unicompartmental knee arthroplasty (UKA). As a secondary objective, this study aims to compare the re-intervention rate in this specific group, between UPC and non-UPC patients. The hypothesis is that the UPC prevalence in patients who undergo a revision TKA after UKA is not higher than in other TKA revision cases and this does not increase the risk of re-intervention. Methods: This is a retrospective study where all patients who underwent a UKA revision from January 2016 to February 2023 in a high-volume arthroplasty centre, were analyzed. Unexpected positive culture prevalence in this group of patients was obtained. Results: During the included period, 270 UKA revision surgeries were performed. Eight cases had at least two positive cultures and were therefore excluded. The final analysis included 262 patients. Of these, 8 (3.05%) patients presented UPCs and the isolated microorganisms were low-virulence organisms. None of the UPC patients received any treatment. No statistical differences were found between UPC and non-UPC groups in the analyzed variables. Conclusion: The prevalence of unexpected positive cultures in patients following revision of unicompartmental knee arthroplasty is lower than in patients who undergo a revision of total knee arthroplasty. In UKA patients a UPC does not seem to increase the risk of a re-intervention, so it can be safely ignored if ICM criteria are not met. [ABSTRACT FROM AUTHOR]