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Objective: This meta-analysis evaluates the comparative efficacy of lateral unicompartmental arthroplasty (UKA) versus medial UKA in treating unicompartmental knee osteoarthritis (KOA). Methods: We systematically searched Cochrane, PubMed, Embase, and Web of Science databases from January 2000 to September 2024. Literature screening, quality assessment, and data extraction were conducted based on predefined inclusion and exclusion criteria. Review Manager 5.4 software was used to analyze postoperative functional scores, pain scores, aseptic loosening, progression of contralateral arthritis, and prosthesis survival. Results: Fifteen cohort studies, encompassing 2,592 knees with medial UKA and 614 knees with lateral UKA, were included. The analysis showed no statistically significant differences in functional scores [SMD = 0.11, 95% CI (− 0.10, 0.33), I2 = 64%, P = 0.31], pain scores [SMD = 0.23, 95% CI: (− 0.22, 0.67), I2 = 91%, P = 0.32], aseptic loosening [OR = 1.33, 95% CI: (0.31, 5.78), I2 = 0%, P = 0.70], progression of contralateral arthritis [OR = 0.37, 95% CI: (0.07, 1.91), I2 = 0%, P = 0.23], short- to intermediate-term survival [OR = 1.40, 95% CI: (0.84, 2.35), I2 = 0%, P = 0.20], and long-term survival [OR = 1.12, 95% CI: (0.61, 2.05), I2 = 0%, P = 0.70]. Conclusion: Our findings indicate no significant differences in functional outcomes, pain relief, aseptic loosening, progression of contralateral arthritis, or prosthesis survival between lateral and medial UKA. Thus, both approaches are reliable options for patients with unicompartmental KOA. [ABSTRACT FROM AUTHOR]

Introduction. Unicompartmental knee arthroplasty (UKA) is a treatment reserved for single-component osteoarthritis. There are two types of UKA prosthesis: mobile bearing (MB) with a moving implant between the femoral and tibial component, and fixed bearing (FB) with a stable one. It is still under debate what kind of UKA is better, with some studies suggesting no difference between MB and FB. Aim of the study. This study aimed to assess and compare the alignment of unicompartmental knee arthroplasties (UKA) and its impact on functional outcome. Material and methods. Sixty-nine adult patients referred for UKA with a set of X-ray pictures were included in this retrospective study. 28 patients were treated with FB and 41 with MB. Two independent researchers evaluated short radiographs for the alignment of both prosthesis components in anterior-posterior and lateral projections. The functional outcome of arthroplasty was assessed by Knee Osteoarthritis and Outcome Score (KOOS) and International Knee Documentation Committee Subjective Knee evaluation form (IKDC) in 41 patients.Results. The femoral component in MB was placed 4 more varus than in FB. On the lateral view, the difference between placements was 5 for MB placed in flexion and FB placed in extension. There were no significant differences in tibial component alignment. The Spearman correlation test showed a moderately strong negative correlation (R = –0.55) between KOOS Q and femur varus/valgus parameters in the MB group with p = 0.03.Conclusions. More varus femoral component placement in the MB group resulted in better functional outcomes. Other components in both FB and MB did not reveal any correlation with functional outcomes.

Abstract Objective To investigate the effect of the flexion angle of a femoral prosthesis on the postoperative clinical outcome of patients with knee osteoarthritis who are undergoing unicompartmental knee arthroplasty. Methods Patients were divided into three groups according to the flexion angle of the femoral prosthesis following unicompartmental knee arthroplasty. Group A comprised patients with a flexion angle of the femur prosthesis of less than 5°, Group B included those with a flexion angle of 5° to 10°, and Group C consisted of patients with a flexion angle of the femur prosthesis greater than 10°. The basic clinical data, visual analog scale (VAS) score, Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and knee range of motion (ROM) were subjected to statistical analysis and comparison between the groups. Results No significant differences were observed in the basic data of the patients in each group. The ROM and VAS scores for the knee in the first month following unicompartmental knee arthroplasty in groups B and C were significantly greater than those in group A. The HSS scores for the knee joint in Group B indicated superior outcomes in the initial postoperative month and the third postoperative month, as evidenced by the WOMAC scores, which demonstrated a statistically significant difference between Group B and the other two groups within the six-month postoperative period. Conclusion The short-term recovery of patients in Group B was the fastest. These results provide a new reference for the installation of femoral prostheses in unicompartmental knee arthroplasty.

Unicompartmental knee arthroplasty (UKA) is an alternative to total knee arthroplasty (TKA) for localized osteoarthritis. Recent advancements in UKA implant design and expanding patient criteria may have increased its utilization. However, few studies have examined the use of UKA in the United States. Thus, this study assessed the current and projected future trends of UKA and robotic UKA in the United States through 2035, along with postoperative outcomes. A collaborative healthcare research network was queried to identify patients who had undergone UKA. Primary outcomes measured included prevalence (P), incidence proportion (IP), and incidence rate (IR) from 2012 to 2022. Chi -squared analyses were done to compare outcomes across categorical data. Regression modeling was performed to project UKA to the year 2035. Statistical significance was held at P <.05 for all analyses. In 2022, 1,662 UKAs were performed within the network, a 590% increase from 2012 (241 performed). The IP increased on an average annual basis by 41.8%, the IR by 50%, and the P by 51.3%. A year following UKA, conversion to TKA was the most common orthopaedic complication (39.9%). As of 2022, there were 68 robotic UKAs performed, a 518% increase from the 11 performed in 2012. Regression analysis for UKA through 2035 showed that IP will be 0.04%, IR will be 1.75 × 10−6 cases/person-day, and P will be 0.3%. These findings are consistent with prior studies indicating a higher utilization of UKA over the past decade. Reported complications were not uncommon, as nearly 40% of patients required a conversion to a TKA. Further research is needed to optimally identify criteria for appropriate patients and determine the benefits robotic UKA may provide, specifically reducing the risk of conversion to a TKA. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of the flexion angle of a femoral prosthesis on the postoperative clinical outcome of patients with knee osteoarthritis who are undergoing unicompartmental knee arthroplasty. Methods: Patients were divided into three groups according to the flexion angle of the femoral prosthesis following unicompartmental knee arthroplasty. Group A comprised patients with a flexion angle of the femur prosthesis of less than 5°, Group B included those with a flexion angle of 5° to 10°, and Group C consisted of patients with a flexion angle of the femur prosthesis greater than 10°. The basic clinical data, visual analog scale (VAS) score, Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and knee range of motion (ROM) were subjected to statistical analysis and comparison between the groups. Results: No significant differences were observed in the basic data of the patients in each group. The ROM and VAS scores for the knee in the first month following unicompartmental knee arthroplasty in groups B and C were significantly greater than those in group A. The HSS scores for the knee joint in Group B indicated superior outcomes in the initial postoperative month and the third postoperative month, as evidenced by the WOMAC scores, which demonstrated a statistically significant difference between Group B and the other two groups within the six-month postoperative period. Conclusion: The short-term recovery of patients in Group B was the fastest. These results provide a new reference for the installation of femoral prostheses in unicompartmental knee arthroplasty. [ABSTRACT FROM AUTHOR]

In light of the fact, that the number of young people undergoing knee arthroplasty is increasing, the question of which types of sport and what intensity of sport is possible after knee arthroplasty is becoming increasingly important. According to the literature patients, especially those with a total knee arthroplasty, do still not achieve high level sports. However, this is not just a problem of the implant itself. There have been developments in implant design like uncemented fixation, medial pivoting bearings etc., that allow the surgeon to adjust their implant choice to the level of sport and physical activity. Beside patient-specific factors like age, weight, coexisting diseases, preoperative activity, and patient motivation it is the surgeon that struggles to implant the knee arthroplasty to accommodate the function level required for high level sport. In addition, most specialty societies have advised against high level sport after knee arthroplasty. However, should the surgeon find ways to implant a knee arthroplasty to accommodate the function level required for high level sports, then utilizing uncemented fixation, high congruency bearings like medial pivoting or ultracongruent etc., restricted alignment targets within 3 deg of neutral and avoiding patella resurfacing might allow for higher activity levels without compromising the long term survival of the implant. Once this has been confirmed by research studies it is likely that the specialty societies will adjust their recommendations. [ABSTRACT FROM AUTHOR]

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Aims: Robotic-assisted unicompartmental knee arthroplasty (R-UKA) has been proposed as an approach to improve the results of the conventional manual UKA (C-UKA). The aim of this meta-analysis was to analyze the studies comparing R-UKA and C-UKA in terms of clinical outcomes, radiological results, operating time, complications, and revisions. Methods: The literature search was conducted on three databases (PubMed, Cochrane, and Web of Science) on 20 February 2024 according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Inclusion criteria were comparative studies, written in the English language, with no time limitations, on the comparison of R-UKA and C-UKA. The quality of each article was assessed using the Downs and Black Checklist for Measuring Quality. Results: Among the 3,669 articles retrieved, 21 studies on 19 series of patients were included. A total of 3,074 patients (59.5% female and 40.5% male; mean age 65.2 years (SD 3.9); mean BMI 27.4 kg/m2 (SD 2.2)) were analyzed. R-UKA obtained a superior Knee Society Score improvement compared to C-UKA (mean difference (MD) 4.9; p < 0.001) and better Forgotten Joint Score postoperative values (MD 5.5; p = 0.032). The analysis of radiological outcomes did not find a statistically significant difference between the two approaches. R-UKA showed longer operating time (MD 15.6; p < 0.001), but reduced complication and revision rates compared to C-UKA (5.2% vs 10.1% and 4.1% vs 7.2%, respectively). Conclusion: This meta-analysis showed that the robotic approach for UKA provided a significant improvement in functional outcomes compared to the conventional manual technique. R-UKA showed similar radiological results and longer operating time, but reduced complication and revision rates compared to C-UKA. Overall, R-UKA seems to provide relevant benefits over C-UKA in the management of patients undergoing UKA. Cite this article: Bone Jt Open 2024;5(5):374–384.

Aims: In-hospital length of stay (LOS) and discharge dispositions following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, it is imperative to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge dispositions following robotic arm-assisted total knee arthroplasty (RO TKA) and unicompartmental arthroplasty (RO UKA) versus conventional technique (CO TKA and UKA). Methods: This large-scale, single-institution study included patients of any age undergoing primary TKA (n = 1,375) or UKA (n = 337) for any cause between May 2019 and January 2023. Data extracted included patient demographics, LOS, need for post anaesthesia care unit (PACU) admission, anaesthesia type, readmission within 30 days, and discharge dispositions. Univariate and multivariate logistic regression models were also employed to identify factors and patient characteristics related to delayed discharge. Results: The median LOS in the RO TKA group was 76 hours (interquartile range (IQR) 54 to 104) versus 82.5 (IQR 58 to 127) in the CO TKA group (p < 0.001) and 54 hours (IQR 34 to 77) in the RO UKA versus 58 (IQR 35 to 81) in the CO UKA (p = 0.031). Discharge dispositions were comparable between the two groups. A higher percentage of patients undergoing CO TKA required PACU admission (8% vs 5.2%; p = 0.040). Conclusion: Our study showed that robotic arm assistance was associated with a shorter LOS in patients undergoing primary UKA and TKA, and no difference in the discharge destinations. Our results suggest that robotic arm assistance could be advantageous in partly addressing the upsurge of knee arthroplasty procedures and the concomitant healthcare burden; however, this needs to be corroborated by long-term cost-effectiveness analyses and data from randomized controlled studies. Cite this article: Bone Jt Open 2023;4(10):791–800.

Purpose: The alignment obtained after unicompartmental knee arthroplasty (UKA) influences the risk of failure. Kinematic alignment after UKA based on Cartier angle restauration is likely to improve clinical outcomes compared with mechanical alignment. The purpose of this study is to analyze the influence of implant alignment and native knee restoration after UKA using the conventional techniques on clinical outcomes. Methods: This retrospective study included 144 medial UKA patients from 2015 to 2020. Radiographic measurements were performed pre- and postoperatively. Outliers were defined as follows: Δ Cartier > 3° (difference between the preoperative and postoperative Cartier angle); Δ MPTA (Medial Proximal Tibial angle) and postoperative TCA (Tibial Coronal component Angle) > 3° (difference between the positioning of the tibial implant and the preoperative proximal tibial deformity). The Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Society (IKS) Function and Knee score, the Forgotten Joint Score (FJS), and the Subjective Knee Value (SKV) were evaluated. A Student t test or a non-parametric Wilcoxon test was used for non-normal data to compare pre- and postoperative values for functional scores and angular measurements. The correlation of postoperative angles with functional outcomes was assessed by the Spearman's rank correlation coefficient. Results : During the inclusion period, 214 patients underwent medial UKA, 71 patients were excluded, and 19 were lost to follow-up leaving 124 patients with 144 knees (20 bilateral UKA) included for analysis with a mean follow-up of 54.7 months ± 22.1 (24–95). The Δ Cartier was significantly correlated with IKS function (R2 = 0.06, p < 0.001) and FJS (R2 = 0.05, p < 0.01) scores. The Δ preoperative MPTA–TCA was significantly correlated (p < 0.001) with KOOS (R2 = 0.38), IKS Knee (R2 = 0.17), IKS function (R2 = 0.34), SKV (R2 = 0.08), and FJS (R2 = 0.37) scores. In subgroup analysis, non-outliers (< 3°) for Δ preoperative MPTA–TCA had better KOOS score (Δ = 23.5, p < 0.001) and IKS Function (Δ = 17.7, p < 0.001) compared to outliers (> 3°) patients. Conclusion : Functional results after medial UKA can be influenced by implant alignment in the coronal plane with slight clinical improvement when positioning the tibial implant close to the preoperative tibial deformity, rather than by restoring the Cartier angle. This series suggests the interest of a more personalized alignment strategy, but these results will have to be confirmed by other controlled studies. Level of evidence: IV, retrospective case series. [ABSTRACT FROM AUTHOR]

Purpose: Meniscal tears or histological meniscal calcifications (in the absence of radiological chondrocalcinosis) are frequent in osteoarthritis. Whether lateral meniscal lesions influence clinical outcomes after medial unicompartmental knee arthroplasty (UKA) is unknown. Methods: We analyzed 130 patients (130 knees) with medial unicompartmental knee arthroplasties between 2005 and 2015. These 130 knees had full articular cartilage thickness in the lateral compartment and no radiological chondrocalcinosis on preoperative radiographs. The lateral meniscus was analyzed with preoperative MRI and a biopsy of the anterior horn at the time of surgery. Synovial fluid was collected and analyzed for calcium pyrophosphate dihydrate crystal deposition (CPPD crystals). Lateral meniscal tears were untreated when detected on MRI or during surgery, with the hypothesis that these tears on the opposite compartment would remain asymptomatic in medial UKA. At average 10-year follow-up, patients were evaluated with clinical and radiographic outcome, with a focus on the risk of joint space narrowing of the lateral femorotibial compartment. Results: CPPD crystals were present in the synovial fluid of 70 knees. Lateral meniscal tears were seen on MRI in 34 (49%) normal meniscuses of the 60 knees without CPPD crystals and in six other knees without histological meniscal calcification despite CPPD crystals. Histological calcification was present on 61 lateral meniscuses with 53 meniscal tears. The results showed no significant differences in the clinical outcomes between knees with lateral meniscal tears or lateral meniscal histological chondrocalcinosis or both lesions and those without these conditions. Additionally, radiographic progression of osteoarthritis in the opposite femorotibial compartment of the knee was not more frequent in patients with these meniscal issues. The ten year cumulative survival rates, measured by the need for total knee arthroplasty, were 91% for knees without meniscal lesions and 92% for knees with these lesions. Conclusion: On this basis, treatment of meniscal tears of the lateral compartment and routine aspiration of the knee to assess for birefringent crystals in the planning of medial UKA do not appear necessary. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients. Patients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P =.049). Patients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P <.001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P <.001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P <.001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P =.52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up. Patients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship. [ABSTRACT FROM AUTHOR]

Background: There is no consensus on whether unicompartmental arthroplasty (UKA) or high tibial osteotomy (HTO) is superior for unicompartmental arthritis. While there are studies comparing revision and complication rates, none matched a large number of patients undergoing HTO and UKA in the United States and compared these outcomes. We investigated TKA conversion rate and the complications following HTO or UKA. Methods: This retrospective study queried the PearlDiver database of all patients undergoing UKA and HTO using CPT codes between January 2011 and January 2020. We compared propensity-matched populations based on age, gender, Charlson comorbidity index, and Elixhauser comorbidity index to compare odds of complications, TKA conversion, and drug use between UKA and HTO groups. Two-independent sample t-test for unequal variances and test of significance were performed. Results: We found 32,583 UKA patients and 816 HTO patients. Each matched group had 535 patients. One-year complication showed higher risk of pneumonia, hematoma, infection, and mechanical complications among HTO patients. UKA patients used narcotics on average of 10.3 days compared to 9.1 days among HTO patients (P < .01). UKA conversion rates were 4.1%, 5.4%, 7.7%, and 9.2% at 1-, 2-, 5-, and 10-year intervals, respectively. HTO conversion rates were less than 2% at 1- and 2-year intervals, 3.4% at 5-year, and 4.5% at 10-year intervals. This difference was statistically significant at 5- and 10-year intervals (P < .01). Conclusions: Using large matched cohorts, HTO may be converted to TKA later than UKA in short- to mid-term follow-up, and HTO patients used opioids for shorter duration.

Background: When comparing functional outcomes of patients with unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA), studies often report the UKA as the preferred procedure; however, recent improvements in the design of modern TKA implants have aimed at narrowing this gap. Purpose: We sought to compare the "feel" of modern TKA implants to that of UKA, using the Forgotten Joint Score (FJS), a validated patient-reported outcome measure. Methods: We performed a retrospective review of patients who underwent TKA and UKA at 2 institutions between 2014 and 2017. All UKA procedures were robotic arm-assisted with a single implant, "traditional TKAs" were performed using traditional posterior-stabilized implants, and "modern TKAs" were performed using posterior-stabilized implants with a modern design. Differences in FJS were assessed using 1-way analysis of variance and independent 2-sample t tests. Results: A total of 600 patients were included in our study, with 200 patients in each surgical subcategory. Mean age was 62.8 ± 10.2 years and mean body mass index was 29.9 ± 4.9. Modern TKA and UKA had similar FJS at 1 year. While modern TKA had a significantly higher FJS than traditional TKA, UKA did not have a significantly higher FJS than traditional TKA. Conclusion: Our retrospective analysis found no significant differences in the FJS of patients who underwent UKA and TKA with a modern design; however, both had superior scores than traditional TKA designs. This finding suggests that modern TKA designs may have the potential to achieve the natural feeling that is typically associated with joint-conserving surgeries such as UKA, although longer follow-up is necessary. [ABSTRACT FROM AUTHOR]

Case: An active 64-year-old patient presented with new-onset lateral knee pain 42 days after an uncomplicated medial unicompartmental knee arthroplasty (UKA). Magnetic resonance imaging and diagnostic injection of local anesthetic identified an avulsion fracture of the popliteus tendon as the source of discomfort. Repair of the tendon to its native footprint was performed with suture anchor fixation. The patient was pain-free and returned to work without restrictions at 12 weeks. Conclusion: We identify a unique cause of knee pain after UKA—avulsion of the popliteus tendon. Successful management of this condition included anatomic repair of the tendon with suture anchor fixation. [ABSTRACT FROM AUTHOR]

Backgrounds and Objectives: The spacer block technique in unicompartmental knee arthroplasty (UKA) has still a concern related to the precise position of the component in the coronal and sagittal planes compared to intramedullary guide technique. The purposes of this study were to explore whether the spacer block technique would improve the radiological alignment of implants and clinical outcomes compared with the outcomes of the intramedullary guide technique in fixed-bearing medial UKA. Materials and Methods: In total, 115 patients who underwent unilateral, fixed-bearing medial UKA were retrospectively reviewed and divided into group IM (intramedullary guides; n = 39) and group SB (spacer blocks; n = 76). Clinical assessment included range-of-motion and patient-reported outcomes. Radiological assessment included the mechanical femorotibial angle, coronal and sagittal alignments of the femoral and tibial components, and coronal femorotibial congruence angle. Results: All clinical outcomes showed no significant differences between groups. The coronal femoral component angle was valgus 2.4° ± 4.9° in IM group and varus 1.1° ± 3.2° (p < 0.001). In group IM, the number of outlier in coronal femoral component angle (<−10° or 10°<) was 3 cases, while in group SB, there was no outlier (p = 0.014). The coronal femorotibial congruence angle was significantly less in group SB (mean 1.9°, range, −3.2°~8.2°) than in group IM (mean 3.4°, range, −9.6°~16.5°) (p = 0.028). Conclusions: In the group SB, the coronal alignment of femoral component was closer to neutral, and outlier was less frequent than in the group IM. The spacer block technique was more beneficial in achieving proper coronal alignment of the femoral component and congruence of femorotibial components compared to the intramedullary guide technique in fixed-bearing medial UKAs. [ABSTRACT FROM AUTHOR]

IntroductionPopliteal cysts are secondary to degenerative changes in the knee joint. After total knee arthroplasty (TKA), 56.7% of patients with popliteal cysts at 4.9 years follow-up remained symptomatic in the popliteal area. However, the result of simultaneous arthroscopic cystectomy and unicompartmental knee arthroplasty (UKA) was uncertain.Case presentationA 57-year-old man was admitted to our hospital with severe pain and swelling in his left knee and the popliteal area. He was diagnosed with severe medial unicompartmental knee osteoarthritis (KOA) with a symptomatic popliteal cyst. Subsequently, arthroscopic cystectomy and unicompartmental knee arthroplasty (UKA) were performed simultaneously. A month after the operation, he returned to his normal life. There was no progression in the lateral compartment of the left knee and no recurrence of the popliteal cyst at the 1-year follow-up.ConclusionFor KOA patients with a popliteal cyst seeking UKA, simultaneous arthroscopic cystectomy and UKA are feasible with great success if managed appropriately.

Background: Isolated antero-medial osteoarthritis (AMOA) of the knee is a distinct pattern of arthritis. Medial arthritis of the knee in select patients can be managed with uni-compartmental arthroplasty (UKA), with studies showing shorter hospital stay, faster rehabilitation and reduced medical complications in the post-operative period compared to TKA. However, the prevalence of AMOA in Indian patients with osteoarthritis of the knee is unknown. The aim of this study was to evaluate the prevalence of AMOA in patients undergoing primary TKA for OA. Methods: This was a prospective evaluation of 2518 knees in 1936 patients who were selected for primary TKA. Pre-operative radiographs were screened based on the Oxford UKA Radiological decision aid and diagnosis of AMOA was established. All 2518 knees underwent primary total knee arthroplasty and cases of AMOA were confirmed intra-operatively based on ACL integrity, lateral compartment wear and medial compartment wear pattern. Cases with AMOA arthritic wear pattern were considered amenable for UKA if radiographs showed intact lateral joint space, intra-operatively those with intact and functional ACL, acceptable patellofemoral wear (Outerbridge I–II). Results: We report a prevalence of 46.94% of AMOA, who were amenable for UKA. Obese patients were more likely to have a damaged or non-functional ACL and more likely to have a high degree of wear, not amenable for UKA (p < 0.05). Non-functional ACL was associated with higher prevalence of posterior extension of arthritic wear. Conclusion: This study demonstrated a high prevalence (46.94%) of antero-medial osteoarthritis (AMOA), amenable for UKA. Patient selection is important for improving outcomes after TKA or UKA. Future studies are warranted to compare outcomes of both UKA and TKA in patients with isolated AMOA of the knee. [ABSTRACT FROM AUTHOR]

Abstract Background Although Oxford unicompartmental knee arthroplasty (UKA) is used in patients of wide age ranges, there is no clear information regarding the age differences in terms of intraoperative femorotibial rotational kinematics and its influence on clinical outcomes. Therefore, this study was conducted to examine the age differences in terms of intraoperative rotational kinematics and postoperative clinical outcomes and to analyze their relationship with classification according to the age group. Methods We investigated 111 knees of patients who underwent Oxford UKA using a navigation system and divided them into two groups: elderly (aged ≥75 years; 48 knees) and nonelderly (aged

Objective: The unicondylar knee arthroplasty (UKA) procedure is primarily indicated for osteoarthritis of the knee. Anterior cruciate ligament (ACL) defects have long been considered a contraindication to UKA. However, recent clinical studies have found that ACL defects do not affect postoperative outcomes in UKA. To elucidate whether ACL defects affect postoperative outcomes in UKA, we performed a systematic review and Meta-analysis of observational cohort studies comparing the effects of ACL defects and intactness on surgical outcomes in UKA.Methods: In this study, we used “Anterior Cruciate Ligament”, “Anterior Cruciate Ligament Injuries” and “Arthroplasty, Replacement, Knee” as the subject terms according to PICOS principles. These subject terms and the corresponding free texts were used to conduct a systematic search in the three major databases PubMed, Embase and Cochrane on December 9, 2021. The main study variables included age, gender, region, definition of ACL defect and diagnosed diseases. The study used a random effect model to pool the effect of 95% CIs. To explore the sources of heterogeneity and to test the stability of the results, a sensitivity analysis was performed.Results: The systematic review found no significant differences in postoperative clinical outcomes in the elderly population when unicondylar replacement was performed in the setting of multiple factors such as injury, defects, longitudinal tear, and synovial bursa injury defined as ACL deficiency. The primary clinical outcomes included postoperative revision, Tegner activity score, and Oxford Knee Score (OKS). After statistical meta-analysis, postoperative outcomes such as postoperative revision (OR, 1.174; 95% CIs, 0.758–1.817) and Tegner activity score (OR, -0.084; 95% CIs, -0.320–0.151) were not statistically different.Conclusion: There was no difference in postoperative revision rates and functional outcomes such as Tegner activity score between the ACL-deficient group compared with the ACL-intact group. For the present results, it is not advisable to consider ACL deficiency as a contraindication of UKA.

Unicompartmental knee arthroplasty (UKA) has seen a revival of popularity in the last thirty years in the United States. The benefits of a medial UKA over the previous 'gold standard' for knee osteoarthritis, the total knee arthroplasty, include increased postoperative range of motion (ROM), maintenance of natural knee mechanics, faster recovery, similar pain relief and decreased morbidity. Mobile-bearing UKA (MB-UKA) implants have been developed to improve polyethylene wear while maintaining normal knee kinematics. In this review, we will cover indications and contraindications for aN MB-UKA, patient selection, and technical tips and tricks., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Adolph V. Lombardi, Jr., MD reports a relationship with Zimmer Biomet that includes: consulting or advisory. Adolph V. Lombardi, Jr., MD reports a relationship with Total Joint Orthopedics that includes: consulting or advisory. Adolph V. Lombardi, Jr., MD reports a relationship with Firstkind Ltd that includes: funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with Parvizi Surgical Innovations that includes: equity or stocks and funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with Recovery Rx that includes: funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with SPR Therapeutics Inc that includes: funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with Prescribe Fit that includes: equity or stocks and funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with Smith and Nephew Inc that includes: funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with SI-BONE Inc that includes: funding grants. Adolph V. Lombardi, Jr., MD reports a relationship with JIS Ventures that includes: equity or stocks. Adolph V. Lombardi, Jr., MD reports a relationship with Joint Development Corporation that includes: equity or stocks. Adolph V. Lombardi, Jr., MD reports a relationship with Operation Walk that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Central Ohio Orthopaedic Management Company that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Current Concepts in Joint Replacement that includes: board membership. Keith Berend, MD reports a relationship with Medacta USA INC that includes: speaking and lecture fees. Keith Berend, MD reports a relationship with Smith and Nephew Inc that includes: funding grants and speaking and lecture fees. Keith Berend, MD reports a relationship with Zimmer Biomet that includes: funding grants. Keith Berend, MD reports a relationship with Total Joint Orthopedics that includes: funding grants. Keith Berend, MD reports a relationship with Firstkind Ltd that includes: funding grants. Keith Berend, MD reports a relationship with Parvizi Surgical Innovations that includes: equity or stocks and funding grants. Keith Berend, MD reports a relationship with Recovery Rx that includes: funding grants. Keith Berend, MD reports a relationship with Prescribe Fit that includes: equity or stocks and funding grants. Keith Berend, MD reports a relationship with SPR Therapeutics Inc that includes: funding grants. Keith Berend, MD reports a relationship with SI-BONE Inc that includes: funding grants. Keith Berend, MD reports a relationship with JIS Ventures that includes: equity or stocks. Keith Berend, MD reports a relationship with Joint Development Corporation that includes: equity or stocks. Adolph V. Lombardi, Jr., MD reports a relationship with Journal of Bone and Joint Surgery Inc that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Journal of Arthroplasty that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Clinical Orthopaedics and Related Research that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Journal of American Academy of Orthopaedic Surgeons that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Journal of Orthopaedics and Traumatology that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with Surgical Technology International that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with The Knee that includes: board membership. Adolph V. Lombardi, Jr., MD reports a relationship with The Bone and Joint Journal that includes: board membership. Keith Berend, MD reports a relationship with Journal of Arthroplasty that includes: board membership. Keith Berend, MD reports a relationship with Reconstructive Review that includes: board membership. Adolph V. Lombardi, Jr., MD has patent with royalties paid to Zimmer Biomet. Adolph V. Lombardi, Jr., MD has patent with royalties paid to Innomed. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: A review of the data supporting robotic systems currently available is presented focussing on precision and reproducibility, radiological outcomes, clinical outcomes, and survivorship. Materials and methods: Scientific literature published on robotic systems for knee arthroplasty was reviewed using the reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria were any study involving robotic-assisted UKA or TKA that reported precision of implant positioning or functional outcomes or range of motion or survivorship, including cadaveric or dry bone studies with a minimum of 6-month follow-up. Results: Thirty-nine studies were identified for robotic-assisted unicompartmental knee arthroplasty, and 24 studies for robotic-assisted total knee arthroplasty. Those that reported on radiological outcomes or cadaver studies consistently demonstrated improved precision with the use of robotic systems irrespective of the system. PROMS and survival data demonstrated equivalent short-term results. However, many studies reported outcomes inconsistently and few had long-term clinical follow-up or survivorship data. Conclusions: This review adds to the body of evidence supporting improved precision and reproducibility with robotic assistance in knee arthroplasty. Despite intensive funding of research into robotic knee systems, there remains considerable heterogeneity in exposure and outcome analysis and few quality long-term studies demonstrating translation to better clinical outcomes and implant survivorship. [ABSTRACT FROM AUTHOR]

Abstract Background The aim of this study was to evaluate and compare the functional outcomes and complication rates of patients in short-term and midterm follow-up period when medial unicompartmental knee arthroplasty (UKA)-applied patients were grouped according to BMI values. Methods One hundred four patients (mean age 60.2 ± 7.4 (range, 49–80)) to whom medial UKA was applied between 2011 to 2016 with a minimum of 2 years follow-up were grouped as normal and overweight (less than 30 kg/m2), obese (30–34.9 kg/m2) and morbidly obese (BMI ≥ 35 kg/m2) according to their BMI. The postoperative Knee Society Scores (KSS), functional Knee Society Scores (fKSS), Oxford Knee Scores (OKS), visual analogue scale (VAS) and range of motion (ROM) results and complication rate of these groups were compared statistically. The implant positioning of the patients requiring revision was analysed according to the Oxford radiological criteria. Results The average BMI of 104 patients was 34.4 (range, 22–56.9). Twenty-six (25%) of these were normal or overweight, 40 (38.5%) were obese and 38 (36.5%) were morbidly obese. However, in these BMI groups, there was no significant difference between the preoperative VAS, postoperative VAS and VAS score changes among these three groups (p > 0.05). The postop KSS, f KSS and OKS were significantly poorer in the morbidly obese group by 75.2, 70.5 and 33.1, respectively. Furthermore, amount of ROM changes (4.2°) were significantly poorer in the morbidly obese group (p

Backgrounds and Objectives: The spacer block technique in unicompartmental knee arthroplasty (UKA) has still a concern related to the precise position of the component in the coronal and sagittal planes compared to intramedullary guide technique. The purposes of this study were to explore whether the spacer block technique would improve the radiological alignment of implants and clinical outcomes compared with the outcomes of the intramedullary guide technique in fixed-bearing medial UKA. Materials and Methods: In total, 115 patients who underwent unilateral, fixed-bearing medial UKA were retrospectively reviewed and divided into group IM (intramedullary guides; n = 39) and group SB (spacer blocks; n = 76). Clinical assessment included range-of-motion and patient-reported outcomes. Radiological assessment included the mechanical femorotibial angle, coronal and sagittal alignments of the femoral and tibial components, and coronal femorotibial congruence angle. Results: All clinical outcomes showed no significant differences between groups. The coronal femoral component angle was valgus 2.4° ± 4.9° in IM group and varus 1.1° ± 3.2° (p < 0.001). In group IM, the number of outlier in coronal femoral component angle (p = 0.014). The coronal femorotibial congruence angle was significantly less in group SB (mean 1.9°, range, −3.2°~8.2°) than in group IM (mean 3.4°, range, −9.6°~16.5°) (p = 0.028). Conclusions: In the group SB, the coronal alignment of femoral component was closer to neutral, and outlier was less frequent than in the group IM. The spacer block technique was more beneficial in achieving proper coronal alignment of the femoral component and congruence of femorotibial components compared to the intramedullary guide technique in fixed-bearing medial UKAs.

PURPOSE OF THE STUDY The purpose of the study is to verify the correct alignment of components of the Oxford medial unicompartmental knee arthroplasty using the Zimmer Microplasty® instrumentation at the beginning of the learning curve. The implantation of prosthetic components of partial knee arthroplasty in proper alignment has an effect on long-term survival of the prosthesis and should eliminate the occurrence of frequent complications. MATERIAL AND METHODS The study group includes 20 patients, 9 men with the mean age of 68 years (range 62–78 years) and 11 women with the mean age of 69 years (range 52–81 years). 13 patients underwent surgery on the right knee and 7 patients on the left knee. The mean length of symptoms was 13 months (range 7–20 months), the mean varus knee deformity was 7° (range 4–12°). The selected patients met both the clinical and radiological criteria for enrolment in the study. In all of them medial unicompartmental knee arthroplasty was performed in 2019 by the same surgeon. After surgery, the parameters of accuracy of alignment of individual prosthetic components were measured on the full-length radiograph of the limb under load. The WOMAC score was recorded preoperatively and one year after surgery and subsequently compared. The knee joint flexion preoperatively and one year after surgery was evaluated. RESULTS The analysis of radiographs revealed that in 12 cases the femoral component was implanted in the mean valgus angle of 1.6° (range 1–3°) and in 8 cases in the mean varus angle of 3° (range 1–5°). All femoral components were implanted in the mean flexion of 7.3° (range 3–11°), no component was implanted in extension. As concerns the tibial component, 19 components were implanted in a neutral or minimum varus angle with the mean value of 1.1° (range 0.3–4°). One component only was implanted in the valgus angle of 1°. All tibial components were implanted with the mean dorsal slope of 6.5° (range 4–8°). The incision was 5 mm deep on average (range 3–6 mm). There was a slight divergence between the components, namely 2.8° on average (range 2–7°) and the distance between the components was 4mm on average (range 3–5 mm). The mean knee joint flexion achieved preoperatively by patients was 115° (range 110–123°), whereas postoperatively the mean flexion achieved was 126° (range 111–138°). The preoperative Womac score was 84.5 points on average (range 64–96 points), whereas postoperatively it was 26.4 points on average (range 7–52 points). None of the components was implanted outside the permitted range, no early complications of the partial replacement (luxation of polyethylene mobile bearing insert, early loosening of the prosthesis, tibial fracture) were observed. DISCUSSION Our radiographic measurements show that when Zimmer Microplasty® instrumentation is used correct alignment of the femoral and tibial component can be achieved and the individual components were correctly aligned within the recommended range. Every single component met the required criteria for alignment. When comparing the values obtained by us in measurements with those obtained by other authors from abroad, similar results regarding the alignment of components were achieved. CONCLUSIONS When using Zimmer Microplasty® instrumentation, excellent results can be achieved also at the beginning of the learning curve of partial knee replacement. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Total knee arthroplasty has been a common treatment for single-compartment osteoarthritis for some time. Less invasive unicompartmental knee arthroplasty has not been widely available due to low survival rates, but with the development of robot-assisted unicompartmental knee arthroplasty, this goal has become more promising. This study observed the postoperative effects and differences between robot-assisted unicompartmental knee arthroplasty and traditional unicompartmental knee arthroplasty in the treatment of osteoarthritis by means of meta-analysis. METHODS: Relevant databases including Wanfang, VIP, CNKI, EMBASE, PubMed, Cochrane Library, and Web of Science were searched by computer in English and Chinese, and the time was from database inception to June 2020. Quality of retrieved articles was assessed. The outcome indicators included operation time, postoperative complications, implant accuracy, posterior slope and revision rate. Meta-analysis of the collected data was carried out using the RevMan 5.3 software provided by the Cochrane Collaboration. RESULTS: (1) A total of 11 articles were included. There were three randomized controlled trials, one low risk bias, one medium risk bias, and one high risk bias. There were four cohort studies and four case-control studies with NOS score above 6, which were of high quality. (2) Meta-analysis results showed that robotassisted unicompartmental knee arthroplasty was superior to traditional surgery in the accuracy of the tibial component placement (MD=-1.32, 95%CI: -1.74 to -0.91, P < 0.000 01), the accuracy of the femoral component placement (MD=-1.71, 95%CI: -2.82 to -0.61, P=0.002), the postoperative tibial posterior slope (MD=-2.40, 95%CI: -2.80 to -2.22, P < 0.000 01), and the revision rate (RR=0.34, 95%CI:0.16-0.72, P=0.005). (3) Although robot-assisted unicompartmental knee arthroplasty took longer time (MD=11.53, 95%CI:5.12-17.94, P=0.000 4), it did not increase the incidence of surgical complications (RR=0.86, 95%CI:0.45- 1.64, P=0.65). CONCLUSION: When performing unicompartmental knee arthroplasty, robot-assisted unicompartmental knee arthroplasty has higher prosthesis positioning accuracy, better postoperative tibial inclination and lower revision rate without increasing the incidence of complications. It is a surgical method that is more ideal than traditional surgical methods, and is worthy of further discussion in clinical practice, but the above conclusions still need to be verified by largesample and high-quality randomized controlled studies. [ABSTRACT FROM AUTHOR]

Background: Although Oxford unicompartmental knee arthroplasty (UKA) is used in patients of wide age ranges, there is no clear information regarding the age differences in terms of intraoperative femorotibial rotational kinematics and its influence on clinical outcomes. Therefore, this study was conducted to examine the age differences in terms of intraoperative rotational kinematics and postoperative clinical outcomes and to analyze their relationship with classification according to the age group.Methods: We investigated 111 knees of patients who underwent Oxford UKA using a navigation system and divided them into two groups: elderly (aged ≥75 years; 48 knees) and nonelderly (aged < 75 years; 63 knees). Intraoperative tibial internal rotational angles relative to the femur during passive knee flexion were measured using a navigation system, and clinical outcomes were evaluated using knee range of motion, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Knee Society Functional Score at 2 years postoperatively. The relationships between intraoperative tibiofemoral rotational angles and clinical outcomes were also evaluated in the two groups.Results: The intraoperative tibial internal rotational angle relative to the femur during knee flexion was significantly larger in the nonelderly group (13.5°) than in the elderly group (9.0°). The intraoperative tibial internal rotational angle showed a positive correlation with the pain subscale of KOOS only in the nonelderly group.Conclusion: Intraoperative rotational kinematics and its influence on clinical outcomes were different between elderly and nonelderly patients, and the tibial internal rotational angle could be a more important factor for successful UKA in nonelderly patients. [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) in isolated unicompartmental disease; however, mid-term to long-term results in young patients are unknown. The purpose of this study is to determine the mid-term outcomes of fixed-bearing medial UKA in patients less than 55 years of age.Methods: Seventy-seven fixed-bearing medial UKAs in patients less than 55 years of age (mean 49.9, range 38-55) from a previously published report were retrospectively reviewed at a mean follow-up of 11.2 years (range 4.1-19.2).Results: Eleven knees were converted to TKA (14.3%) at 0.7-13.8 years postoperatively. The indications for revision included 7 for unexplained pain (9.1%), 2 for grade 4 arthritic progression (1 isolated lateral and 1 lateral and patellofemoral compartments; 2.6%), 1 for polyethylene wear (1.3%), and 1 for femoral component loosening (1.3%). Predicted survivorship free from component revision was 90.4% (95% confidence interval 86.9-93.9) at 10 years and 75.1% (95% confidence interval 66.2-84.0) at 19 years. The mean Knee Society Score improved from a mean of 51.9-88.6 points (P < .001). Of the 52 knees with 4-year minimum radiographs, 3 (5.8%) developed isolated grade 4 patellofemoral arthritis that was asymptomatic, and no knees had evidence of component loosening or osteolysis.Conclusion: Fixed-bearing medial UKA is a durable option for young patients with unicompartmental arthritis, with good clinical outcomes at mid-term follow-up. Unexplained pain was the most common reason for revision to TKA. [ABSTRACT FROM AUTHOR]

Background: The volume of unicompartmental knee arthroplasty (UKA) has increased dramatically in recent years with good reported long-term outcomes. UKA can be performed under general or neuraxial (ie, spinal) anesthesia; however, little is known as to whether there is a difference in outcomes based on anesthesia type. The purpose of the present study is to compare perioperative outcomes between anesthesia types for patients undergoing primary elective UKA.Methods: Patients who underwent primary elective UKA from 2007 to 2017 were identified from the American College of Surgeons-National Surgical Quality Improvement Program Database. Operating room times, length of stay (LOS), 30-day adverse events, and readmission rates were compared between patients who received general anesthesia and those who received spinal anesthesia. Propensity-adjusted multivariate analysis was used to control for selection bias and baseline patient characteristics.Results: A total of 8639 patients underwent UKA and met the inclusion criteria for this study. Of these, 4728 patients (54.7%) received general anesthesia and 3911 patients (45.3%) received spinal anesthesia. On propensity-adjusted multivariate analyses, general anesthesia was associated with increased operative time (P < .001) and the occurrence of any severe adverse event (odds ratio [OR], 1.39; 95% confidence interval [95% CI], 1.04-1.84; P = .024). In addition, general anesthesia was associated with higher rates of deep venous thrombosis (OR, 2.26; 95% CI, 1.11-4.6; P = .024) and superficial surgical site infection (OR, 1.04; 95% CI, 0.6-1.81; P < .001). Finally, general anesthesia was also associated with a reduced likelihood of discharge to home (OR, 0.72; 95% CI, 0.59-0.88; P < .001). No difference existed in postoperative hospital LOS or readmission rates among cohorts.Conclusion: General anesthesia was associated with an increased rate of adverse events and increased operating room times as well as a reduced likelihood of discharge to home. There was no difference in hospital LOS or postoperative readmission rates between anesthesia types. [ABSTRACT FROM AUTHOR]

Background: Several recent studies have recommended offering unicompartmental knee arthroplasty (UKA) to all patients regardless of body mass index (BMI). The aim of this investigation was to evaluate the proposition that UKA can indeed be offered to the morbidly-obese and super-obese (morbidly-obese, BMI ≥ 40 kg/m2) without compromising results or survivorship.Methods: We retrospectively reviewed mobile-bearing medial UKA procedures performed at our facility from January 2012 to May 2015 with a minimum of 2-year follow-up. The study cohort was divided into patients with morbid obesity (BMI ≥ 40 kg/m2) and those without morbid obesity (BMI < 40 kg/m2). A detailed medical record review was performed. Extracted outcome data included the frequency of (1) major revision procedures (components revised), (2) minor secondary procedures (components not revised), (3) infection procedures, and (4) recommendations for revision.Results: We found 152 patients (190 knees) who met criteria for inclusion. Mean follow-up duration was 3.4 years (range: 2.0-6.8 years). Major revision surgery occurred more frequently in the morbid-obesity UKA group (15.7% vs 3.0%, P < .01). Rates of minor secondary surgery and infection were comparable for both groups. Most failures in the morbid-obesity UKA group (85.7%) were due to disease progression involving other compartments or mobile-bearing instability.Conclusion: We found the rate of early major revision surgery in morbidly-obese patients undergoing UKA to be over 5-times greater than that of other patients. Failure was predominantly due to disease progression in other compartments or mobile-bearing instability. Further study is warranted and needed before expanding UKA indications to the morbidly-obese population. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the past, the main end-stage treatment of osteoarthritis was joint replacement surgery. In recent years, with the prevalence of the concept of knee-protection and the continuous development of internal fixation materials and surgical techniques, unicompartmental replacement, a minimally invasive technique, has been widely used in the treatment of patients with single-chamber osteoarthritis. OBJECTIVE: To compare the efficacy of unicompartmental knee arthroplasty in osteoarthritis patients using robotic-assisted or traditional manual methods by meta-analysis systematically. METHODS: We searched for clinical control studies published from 1999 to March 2019. The retrieved databases included Embase, PubMed, Central, Cinahl, PQDT, CNKI, CQVIP, Wanfang, Cochrane Library, CBM and other databases. Five outcomes including tibial component implantation accuracy, femoral component implantation accuracy, tibiofemoral component safety zone, operation time and complications were selected to compare the efficacy differences between robotic-assisted techniques and traditional manual methods systematically. RESULTS AND CONCLUSION:(1) According to the above retrieval strategies, eight foreign literatures were included.(2) By comparison, we found that the robotic-assisted unicompartmental knee arthroplasty was superior to manual methods in the accuracy of tibial component placement [95%CI(-2.13,-0.63), P=0.000 3], femoral component placement [95%CI(-2.49,-0.32), P=0.01] and the tibiofemoral component safety zone [95%CI(1.05, 17.57), P=0.04] with significant statistical difference.(3) Although robotic assistant technology took longer operation time [95%CI(12.58, 42.33), P=0.000 3], it did not increase the incidence of complications [95%CI(0.75, 3.71), P=0.21].(4) In unicompartmental replacement surgery, robotic assistant technology has higher accuracy and does not increase the incidence of complications. It is a more ideal surgical method than traditional manipulation. These conclusions need to be validated by a larger sample and a higher quality randomized controlled study. [ABSTRACT FROM AUTHOR]

Purpose: Long-term clinical and radiographic results and survival rates were compared between closed-wedge high tibial osteotomy (HTOs) and fixed-bearing unicompartmental knee arthroplasty (UKA) in patients with similar demographics.Methods: Sixty HTOs and 50 UKAs completed between 1992 and 1998 were retrospectively reviewed. There were no significant differences in pre-operative demographics. The mean follow-up period was 10.7 ± 5.7 years for HTO and 12.0 ± 7.1 years for UKA (n.s.). The Knee Society knee and function scores, WOMAC, and range of motion (ROM) were investigated. The mechanical axis and femorotibial angle were evaluated. Kaplan-Meier survival analysis was performed (failure: revision to TKA) and the failure modes were investigated.Results: Most of the clinical and radiographic results were not different at the last follow-up, except ROM; ROM was 135.3° ± 12.3° in HTO and 126.8° ± 13.3° in UKA (p = 0.005). The 5-, 10-, 15-, and 20-year survival rates were 100%, 91.0%, 63.4%, and 48.3% for closed-wedge HTO, respectively, and 90.5%, 87.1%, 70.8%, and 66.4% for UKA (n.s.). The survival rate was higher than that for UKA until 12 years post-operatively but was higher in UKAs thereafter, following a remarkable decrease in HTO. The most common failure mode was degenerative osteoarthritic progression of medial compartment in HTO and femoral component loosening in UKA.Conclusions: Long-term survival did not differ significantly between closed-wedge HTO and fixed-bearing UKA in patients with similar pre-operative demographics and knee conditions. The difference in post-operative ROM and failure mode should be considered when selecting a procedure.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this case-control study was to compare implant position and revision rate for UKA, performed with either a robotic-assisted system or with conventional technique.Methods: Eighty UKA (57 medial, 23 lateral) were performed with robotic assistance (BlueBelt Navio system) between 2013 and 2017. These patients were matched with 80 patients undergoing UKA using the same prosthesis, implanted using conventional technique. The sagittal and coronal component position was assessed on postoperative radiographs. The revision rate was reported at last follow-up.Results: The mean follow-up was 19.7 months ± 9 for the robotic-assisted group, and 24.2 months ± 16 for the control group. The rate of postoperative limb alignment outliers (± 2°) was significantly higher in the control group than in the robotic-assisted group for both lateral UKA (26% in robotic group versus 61% in control group; p = 0.018) and medial UKA (16% versus 32%, resp.; p = 0.038). The coronal and sagittal tibial baseplate position had significantly less outliers (± 3°) in the robotic-assisted group, than in the control group. Revision rates were: 5% (n = 4/80) for robotic assisted UKA and 9% (n = 7/80) for conventional UKA (n.s.). The reasons for revision were different between groups, with 86% of revisions in the control group occurring in association with component malposition or limb malalignment, compared with none in the robotic-assisted group.Conclusion: Robotic-assisted UKA has a lower rate of postoperative limb alignment outliers, as well as a lower revision rate, compared to conventional technique. The accuracy of implant positioning is improved by this robotic-assisted system.Level Of Evidence: Level of evidence III. Retrospective case-control study CLINICAL RELEVANCE: This is the first paper comparing implant position, clinical outcome, and revision rate for UKA performed using the Navio robotic system with a control group. [ABSTRACT FROM AUTHOR]

In 2012-2014 total 67 unicompartmental arthroplasty surgeries with use of Oxford knee meniscal bearing were performed. The surgeries were performed by a single surgeon. Minimally invasive approach was used. All patients were evaluated clinically, radiographically and with Oxford Knee score scale, Knee Society score scale and functional scale. Obtained data was processed with nonparametric Mann-Whitney-Wilcoxon test. Results were processed using the statistical analysis application package SPSS, version 10.07. Analysis of of mid-term results showed that the average for Oxford Knee score increased from 16.4 (95% CI 9-23) to 41.3 (95% CI 29-47). Average for Knee Society score scale increased from 42.7 (95% CI 31-55) to 88.6 (95% CI 73-100). No occurrence of early postoperative complications have been reported. Statistically significant improvements of knee function in patients after unicompartmental arthroplasty have been observed. Unicompartmental arthroplasty currently can be considered as an advanced treatment option for medial knee joint pathology. Meniscal bearing cemented prostheses such as Oxford III are preferable.

Objectives: This study aims to provide a comprehensive comparative analysis of functional outcomes between Unicompartmental Knee Arthroplasty (UKA) and Total Knee Arthroplasty (TKA) in patients diagnosed with bilateral knee osteoarthritis. Both procedures were performed simultaneously on separate knees to evaluate their respective efficacy., Methods: The study included 25 patients (18 women and 7 men) with a mean age of 59.6 years, all meeting the criteria for administering UKA on one knee and TKA on the other. Radiographic and clinical data were collected over a two-year period, with assessments conducted at 6 months, 1 year, and 2 years postoperatively. Data included age, gender, and body mass index, medical history, surgical procedures, and various scores and measurements related to knee function., Results: The UKA group exhibited significant improvements in functional scores compared to the TKA group. Specifically, the Western Ontario and McMaster Universities Osteoarthritis Index score for the UKA knee was 24.5% higher than that of the TKA knee, indicating better functional outcomes. Radiographically, the tibio-femoral angle was more than two times greater in the UKA method, while the Varus angle was significantly greater in the TKA method. No post-operative complications were reported., Conclusion: This study underscored the safety and efficacy of both UKA and TKA procedures in the treatment of bilateral knee osteoarthritis. UKA demonstrated superior functional outcomes, while TKA displayed distinct advantages in radiographic alignment. Individual patient characteristics and preferences should guide the selection of the most appropriate surgical approach., Competing Interests: The authors do NOT have any potential conflicts of interest for this manuscript., (Copyright © 2024 Mashhad University of Medical Sciences.)

Wear-related complications remain a major issue after unicompartmental arthroplasty. We used a computational model to predict knee wear generated in vitro under diverse conditions. Inverse finite element analysis of 2 different total knee arthroplasty designs was used to determine wear factors of standard and highly crosslinked polyethylene by matching predicted wear rates to measured wear rates. The computed wear factor was used to predict wear in unicompartmental components. The articular surface design and kinematic conditions of the unicompartmental and tricompartmental designs were different. Predicted wear rate (1.77 mg/million cycles) was very close to experimental wear rate (1.84 mg/million cycles) after testing in an AMTI knee wear simulator. Finite element analysis can predict experimental wear and may reduce the cost and time of preclinical testing.

Background: Contemporary research has shown medial mobile-bearing unicompartmental knee arthroplasty to be an effective treatment in patients younger than 60 years; however, only one other study has specifically investigated unicompartmental arthroplasty outcomes in patients 50 years or younger. The purpose of this study was to determine the clinical outcomes and survivorship of medial mobile-bearing unicompartmental arthroplasty in this younger patient population.Methods: A retrospective review of patients undergoing primary unicompartmental knee arthroplasty using the Oxford partial knee from 2003 to 2014 in a single practice database was performed. Patients were included in the study if they were 50 years of age or younger with a primary diagnosis of anteromedial osteoarthritis and minimum clinical follow-up of 2 years. Patient clinical outcomes, function, and need for revision surgery were assessed.Results: The study included 340 knees. Average patient age was 46.5 years, and the mean follow-up was 6.1 years. Patients demonstrated significant improvements (P < .05) in range of motion (114.5 v 116.9), University of California Los Angeles activity score (4.4 vs 5.6), Knee Society clinical (37.3 vs 86.5) and functional scores (58.8 v 79.8). Overall, 20 patients required reoperation, and the predicted survival rate was 96% at 6 years and 86% at 10 years. Aseptic loosening occurred in 7 patients at an average of 5.6 years postoperatively, while 4 patients required conversion to total knee arthroplasty because of arthritic progression at a mean time of 6.6 years. There were no revision procedures required due to polyethylene liner wear or breakage.Conclusion: Medial mobile-bearing unicompartmental arthroplasty should be considered as a treatment option in patients younger than 50 years of age suffering from anteromedial osteoarthritis of the knee. [ABSTRACT FROM AUTHOR]

Isolated patellofemoral arthritis (IPA) is a debilitating condition characterised by a loss of articular cartilage on the patella facets, the trochlear groove or both. By definition, patients with IPA must have normal cartilage in the tibiofemoral compartments of their knee. It is therefore logical to pursue arthroplasty which corrects the abnormality while sparing healthy bone and preserving the knee’s native kinematics, which is the premise underpinning patellofemoral arthroplasty (PFA). However, its use remains controversial, with many surgeons still favouring total knee replacement (TKR) in these patients. This paper provides a comprehensive review of PFA in the literature to date and concludes, in carefully selected patients, PFA is worthy of consideration as a functionally superior and economically beneficial joint-preserving procedure – delaying TKR until implant failure or tibiofemoral osteoarthritis progression. [ABSTRACT FROM AUTHOR]

Unicompartmental knee replacement (UKR) is an effective treatment for end-stage, symptomatic unicompartmental osteoarthritis of the knee. However, certain aspects of the procedure are still debated. These areas of discussion include patient selection criteria, implant design and the discrepancy in survival rates between national registries and independent case series. These may contribute in limiting the more widespread acceptance of unicompartmental knee replacement. The aim of this paper is to review the up-to-date evidence on UKR and discuss the most relevant controversies regarding this procedure. [ABSTRACT FROM AUTHOR]

Purpose: Joint-line restitution is one objective of unicompartmental knee arthroplasty (UKA). However, the joint line is often lowered when resurfacing femoral implants are used. The aim of this study was to compare the joint-line height in UKA performed by robotic-assisted and conventional techniques.Methods: This retrospective case-control study compared two matched groups of patients receiving a resurfacing UKA between 2013 and 2016 by either a robotic-assisted (n = 40) or conventional (n = 40) technique. Each group comprised 27 women and 13 menm wuth a mean age of 69 and 68 years, respectively. Indications for surgery were osteoarthritis (n = 35) and condylar osteonecrosis (n = 5). Two validated radiologic measurement methods were used to assess joint-line height.Results: Forty UKA (23 medial and 17 lateral) were analysed in each group. Restitution of joint-line height was significantly improved in the robotic-assisted group compared than the control group: +1.4 mm ±2.6 vs +4.7 mm ± 2.4 (p < 0.05) as assessed using method 1, and +1.5 mm ±2.3 vs +4.6 mm ±2.5 (p < 0.05) as assessed using method 2.Conclusions: Restitution of joint-line height in resurfacing UKA can be improved with robotic-assisted surgery. Improvement in clinical outcome measures must be demonstrated with long-term studies. [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) is a treatment option for single-compartment knee osteoarthritis. Robotic assistance may improve survival rates of UKA, but the cost-effectiveness of robot-assisted UKA is unknown. The purpose of this study was to delineate the revision rate, hospital volume, and robotic system costs for which this technology would be cost-effective.Methods: We created a Markov decision analysis to evaluate the costs, outcomes, and incremental cost-effectiveness of robot-assisted UKA in 64-year-old patients with end-stage unicompartmental knee osteoarthritis.Results: Robot-assisted UKA was more costly than traditional UKA, but offered a slightly better outcome with 0.06 additional quality-adjusted life-years at an incremental cost of $47,180 per quality-adjusted life-years, given a case volume of 100 cases annually. The system was cost-effective when case volume exceeded 94 cases per year, 2-year failure rates were below 1.2%, and total system costs were <$1.426 million.Conclusion: Robot-assisted UKA is cost-effective compared with traditional UKA when annual case volume exceeds 94 cases per year. It is not cost-effective at low-volume or medium-volume arthroplasty centers. [ABSTRACT FROM AUTHOR]

Purpose: The pattern of symptoms of knee osteoarthritis has been thought to be indicative of specific compartment involvement. This study investigated whether there was a true correlation between patellofemoral joint (PFJ) symptoms and unicompartmental patellofemoral arthritis. Materials and Methods: A prospective analysis of 34 patients rendered to be suffering from PFJ osteoarthritis and subsequently undergoing unicompartmental patellofemoral arthroplasty (PFA) was performed. A control cohort of 32 patients suffering from medial tibiofemoral joint (MTFJ) osteoarthritis was included in the analysis. Four questions derived from the Oxford knee score questionnaire, traditionally deemed to be indicative of PFJ osteoarthritis, were combined to create a PFJ subscore and statistically analyzed for their potential relationship with PFJ osteoarthritis and outcomes following PFA. Results: The PFJ subscore indicated slightly worse pathology in patients undergoing PFA compared to MTFJ replacement, but the difference was not significant (9.7 and 9.6, respectively; p=0.851). The improvement in PFJ symptoms was higher in those undergoing PFA compared to MTFJ surgery; however, the difference was not statistically significant (3.7 and 2.2 respectively, p=0.074). Conclusions: We were unable to prove that these symptoms were predictive of PFJ pathology in the preoperative setting, nor were they useful in interpreting which symptoms would likely improve following PFA. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the causes and types of complications after unicompartmental knee arthroplasty (UKA) and determine proper prevention and treatment methods. Materials and Methods: A total of 1,576 UKAs were performed for osteoarthritis of the knee from January 2002 to December 2014 at one institution. We analyzed complications after UKA retrospectively and investigated proper methods of treatment. Results: A total of 89 complications (5.6%) occurred after UKA. Regarding the type of complications after UKA, there were 42 cases of dislocation of the mobile bearing, 23 cases of loosening of the prosthesis, 6 cases of periprosthetic fracture, 3 cases of polyethylene wear, 3 cases of progression of arthritis in the contralateral compartment, 2 cases of medial collateral ligament injury, 2 cases of impingement, 5 cases of infection, 1 case of arthrofibrosis, and 2 cases of failure due to unexplained pain. The most common complication after UKA was mobile bearing dislocation in the mobile-bearing knees and loosening of the prosthesis in the fixed-bearing knees, but polyethylene wear and progression of arthritis were relatively rare. The complications were treated with conversion to total knee arthroplasty in 58 cases and simple bearing change in 21 cases. Conclusions: The most common complication after UKA was dislocation of the mobile bearing. When a complication occurs after UKA, appropriate treatment should be performed after accurate analysis of the cause of complication. [ABSTRACT FROM AUTHOR]

The purpose of this systematic review is to collate results of studies comparing fixed and mobile bearing unicompartmental knee arthroplasty (UKA), focusing on complications and timing for reoperations. Out of 723 results derived from PubMed, EMBASE and Cochrane database search engines on bearings in arthroplasty, 10 studies comparing clinical results of fixed bearings to mobile bearings in UKA were found eligible for analysis. The reoperation rate was calculated using a novel method such as reoperations per hundred component years, and the causes of specific reoperations were investigated. The overall reoperation rate per hundred component years was similar between the mobile bearings (1.392) and fixed bearings (1.377); however, mobile bearings were more susceptible to reoperations in cases with aseptic loosening (0.393>0.255), progression of arthritis (0.428>0.357) and implant dislocation (0.286>0). The overall incidence of complications is similar for fixed and mobile bearing designs in UKA. The discussion on complications presented above may assist surgeons in their choice of bearing design. [ABSTRACT FROM AUTHOR]

Purpose: The lateral compartment of the knee is biomechanically and anatomically different from the medial compartment. Most commercially available unicompartmental implants are not designed specifically for the lateral compartment. Patient-specific custom-made unicompartmental knee arthroplasty (UKA) are designed to provide optimal fit on both femoral and tibial surfaces. This study aimed to determine if the use of patient-specific lateral unicompartmental implants provide better bone coverage than standard, off-the-shelf commercially available unicompartmental implants in lateral unicompartmental knee arthroplasties. As a secondary question, we wished to determine if patient-specific unicompartmental implants provide good clinical outcomes in surgical treatment of lateral unicompartmental osteoarthritis. Methods: We prospectively evaluated 33 patients who underwent lateral unicompartmental arthroplasty using patient-specific implants and instrumentation with a minimum of 24 months of follow-up. We analysed bone coverage observed in plain radiographs in 33 patient-specific lateral unicompartmental arthroplasties and compared to 20 lateral unicompartmental arthroplasties performed with commercially-available, standard off-the-shelf unicondylar implants. Results: The mean tibial implant lateral coverage mismatch in the patient-specific implant group was 1.0 mm (S.D. 1.2, range 0-5.7 mm ) versus 3.3 mm (S.D. 2.43, range 0.4-7.8 mm) in the conventional implant group ( p < 0.01). In the patient specific cohort, pre-operative limb alignment was 3.3 (valgus) and post-operative limb alignment was −0.9 (varus). The Knee Society score improved from 48 (S.D. 16.2) to 95 (S.D. 7.6). Survivorship in the patient-specific implant group was 97% at an average follow up of 37 months, versus 85% at a follow-up period of 32 months for the standard implant group. Conclusions: Patient-specific lateral unicompartmental knee replacements demonstrated better tibial coverage and provide excellent short-term clinical and radiological results as compared to a standard lateral UKA. [ABSTRACT FROM AUTHOR]