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Background: Early studies in the literature reported relatively high early minor reintervention rate for the mobile-bearing unilateral knee arthroplasty (UKA) compared with short- and midterm survivorship after fixed- or mobile-bearing UKA. However, whether the long-term function and survivorship are similar is unclear.Questions/purposes: We therefore asked whether (1) mobile- or fixed-bearing UKAs have comparable function (as measured by the Knee Society scores); (2) mobile- and fixed-bearing UKA have comparable Knee Society radiographic scores; and (3) the long-term survivorship is comparable.Methods: We retrospectively reviewed 75 patients (79 knees) with a fixed-bearing UKA and 72 patients (77 knees) with a mobile-bearing UKA operated on between 1989 and 1992. Mean age of the patients was 63 years; gender and body mass index (26 kg/m(2)) were comparable in the two groups. We obtained Knee Society function and radiographic scores and determined survival. The minimum followup was 15 years (mean, 17.2 ± 4.8 years; range, 15-21.2 years).Results: The mean Knee Society function and knee scores were comparable in the two groups. Radiographically, the number of overcorrections and the number of radiolucencies were statistically higher in the mobile-bearing group (69% versus 24%). At final followup, considering revision for any reason, 12 of 77 (15%) UKAs were revised (for aseptic loosening, dislocation, and arthritis progression) in the mobile-bearing group and 10 of 79 (12%) in the fixed-bearing group (for wear and arthritis progression).Conclusions: This long-term study did not demonstrate any difference in survivorship between fixed and mobile-bearing but pointed out specific modes of failure. [ABSTRACT FROM AUTHOR]

Unlabelled: Recent literature suggests patients achieve substantial short-term functional improvement after combined bicompartmental implants but longer-term durability has not been documented. We therefore asked whether (1) bicompartmental arthroplasty (either combined medial unicompartmental knee arthroplasty (UKA) and femoropatellar arthroplasty (PFA) or medial UKA/PFA, or combined medial and lateral UKA or bicompartmental UKA) reliably improved Knee Society pain and function scores; (2) bicompartmental arthroplasty was durable (survivorship, radiographic loosening, or symptomatic disease progression); (3) we could achieve durable alignment; and (4) the arthritis would progress in the unresurfaced compartment. We retrospectively reviewed 84 patients (100 knees) with bicompartmental UKA and 71 patients (77 knees) with medial UKA/PFA. Clinical and radiographic evaluations were performed at a minimum followup of 5 years (mean, 12 years; range, 5-23 years). Bicompartmental arthroplasty reliably alleviated pain and improved function. Prosthesis survivorship at 17 years was 78% in the bicompartmental UKA group and 54% in the medial UKA/PFA group. The high revision rate, compared with total knee arthroplasty, may be related to several factors such as implant design, patient selection, crude or absent instrumentation, or component malalignment, which can all contribute to the relatively high failure rate in this series.Level Of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Unlabelled: With substantial interest devoted to improving knee flexion after TKA, it is important to document the relationship between high range of motion and patient-rated outcomes shown. We therefore asked whether single-design high-flexion mobile-bearing posterior-stabilized TKA resulted in: (1) improved knee function; (2) satisfying subjective results; (3) participation recreational and sporting activities; and (4) function correlated to the final range of motion. We prospectively followed 445 consecutive patients having 516 TKAs from September 2000 to January 2005. The same high-flexion posterior-stabilized mobile-bearing implant was used in all patients. Mean patient age was 71 +/- 8 years and mean body mass index was 28 +/- 4 kg/m(2). The minimum clinical followup was 2 years (mean, 3 years; range, 2-4 years). The postoperative range of knee flexion was 128 degrees +/- 4 degrees and the mean Knee Society function and knee scores were 91 +/- 6 and 96 +/- 3, respectively. Eighty-two percent of patients were involved in sporting activities and 86% returned to their previous level of activity. These data confirm that high postoperative range of knee flexion improve patient-rated outcomes.Level Of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Unlabelled: While the literature suggests lateral unicondylar knee arthroplasty (UKA) improves function in the short- and medium-term, it is less clear on longer-term function. We asked (1) whether lateral UKA improved longer-term Knee Society scores and return to previous activity level); (2) whether there were any concerning longer-term radiographic findings (the Knee Society roentgenographic evaluation and scoring system); and (3) whether lateral UKA was durable as measured by survivorship to revision at 10 and 16 years. We retrospectively reviewed 39 patients with 40 lateral cemented metal-backed UKA. The patients had a mean age of 61 years at surgery. The etiologies were primary osteoarthritis in 24 knees, posttraumatic in 12 cases, and osteonecrosis in four cases. We performed clinical and radiographic evaluations at a minimum followup of 3 years (mean, 12.6 years; range, 3-23 years). Prostheses survivorship was 92% at 10 years and 84% at 16 years. Despite the limited number of indications and technical considerations, our data suggest lateral UKA is a reasonable alternative for isolated lateral femorotibial compartment disease.Level Of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Traditionally in total knee arthroplasty (TKA), a post-operative neutral alignment was the gold standard. This principle has been contested as functional outcomes were found to be inconsistent. Analysis of limb alignment in the non-osteoarthritic population reveals variations from neutral alignment and consideration of a personalized or patient-specific alignment in TKA is challenging previous concepts. The aim of this review was to clarify the variations of current personalized alignments and to report their results. Current personalized approaches of alignment reported are: kinematic, inverse kinematic, restricted kinematic, and functional. The principle of “kinematic alignment” is knee resurfacing with restitution of pre-arthritic anatomy. The aim is to resurface the femur maintaining the native femoral joint line obliquity. The flexion and extension gaps are balanced with the tibial resection. The principle of the “inverse kinematic alignment” is to resurface the tibia with similar medial and lateral bone resections in order to keep the native tibial joint line obliquity. Gap balancing is performed by adjusting the femoral resections. To avoid reproducing extreme anatomical alignments there is “restricted kinematic alignment” which is a compromise between mechanical alignment and true kinematic alignment with a defined safe zone of alignment. Finally, there is the concept of “functional alignment” which is an evolution of kinematic alignment as enabling technology has progressed. This is obtained by manipulating alignment, bone resections, soft tissue releases, and/or implant positioning with a robotic-assisted system to optimize TKA function for a patient’s specific alignment, bone morphology, and soft tissue envelope. The aim of personalizing alignment is to restore native knee kinematics and improve functional outcomes after TKA. A long-term follow-up remains crucial to assess both outcomes and implant survivorship of these current concepts.

The COVID-19 pandemic highlighted the need for efficient use of hospital infrastructure. The hypothesis was that a rapid shift to outpatient surgery after hip or knee arthroplasty could be implemented without compromising quality of care. The aim of this study was to assess the safety, pain management and patient-reported outcomes before and after the implementation of an accelerated discharge program using a digital follow-up tool. A retrospective cohort design was used to compare 97 patients who received primary total hip or knee arthroplasty during the pandemic (early discharge) to comparable 194 pre-pandemic patients (normal discharge). Both cohorts had the same inclusion criteria and were closely monitored using the digital follow-up tool. The accelerated discharge program reduced length of stay from a median of 3 days (before the pandemic) to a median of 1 day (during the pandemic) ( p < 0.001). The complication rate of 2% was the same for both groups ( p > 0.05). Patient-reported outcomes for matched samples of hip (n = 100) and knee (n = 82) arthroplasty patients were similar before, at 6 weeks and 3 months after surgery for both groups ( p > 0.05). There were no differences in pain and medication consumption for the first 6 weeks ( p > 0.05). This study demonstrates that reducing length of stay from three to one night after total knee or hip arthroplasty, with the help of a digital follow-up tool, results in a stable rate of complications, readmission, and comparable clinical outcomes, while reducing the socio-economic burden on the health system.

Background: Return to sport after Knee Arthroplasty has been investigated reporting modifications in the physical activities with a trend towards to lower impact sports after Unicompartemental Knee Arthroplasty. The purpose of this study was to analyze the return to sport level after medial unicompartmental knee arthroplasty (MUKA) in a population of osteoarthritic patients having practiced impact sport, defined with a University of California at Los Angeles activity scale (UCLA)≥9 in their pre-symptomatic arthritic period., Hypothesis: Return to an impact sport after MUKA was possible for a population of osteoarthritic patients having practiced impact sport in their pre-symptomatic arthritic period., Methods: Ninety-two MUKA with a pre-symptomatic arthritic UCLA score≥9, including 60 men (65.2%) and operated between January 2009 and September 2014, were evaluated by a dedicated survey. Informations were obtained concerning the physical activities (intensity, frequency, kind of sport, reasons to decrease or stop the physical activities in the pre- and the postoperative period). The average age was 64.9 years±6.4 (range 49-74.4). Three different periods were compared: pre-symptomatic arthritic, preoperative and postoperative period. The mean follow-up was 7.3±1.7 years., Results: The mean pre-symptomatic arthritic UCLA score was 9.9±0.3, the mean preoperative UCLA score was 7.0±2.5 (2-10) and the mean postoperative UCLA score was 7.2±2.0 (3-10). There were significant differences for the mean UCLA score values between pre-symptomatic arthritis and postoperative UCLA scores (p=0.034), however no difference was detected in mean score values before and after surgery (p=0.09). Only 32.6% (30/92) of patients had a postoperative UCLA score≥9. For patients practicing an impact sport activity (UCLA≥9) in the preoperative period (23/92; 25%), the postoperative UCLA score was at 8±1.1 (range 4-10). In this subgroup, 47.8% (11/23) of patients had a postoperative UCLA score≥9. The decline in sports in postoperative was predominantly explained by residual pain of the operated knee (31/92; 34%), precaution to not damage the prosthesis (25/92; 27%) and restrictions due to another joint (19/92; 21%)., Discussion: Return to impact sport after MUKA seems to be limited to a restrained number of patients. The main reasons to the decline in sporting activity level are linked to the residual pain of the operated knee and the precaution to not damage the prosthesis., Level of Evidence: IV, retrospective cohort study., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

The extramedullary guides for the tibial resection during medial unicompartmental knee arthroplasty (UKA) are inaccurate, with an error risk in coronal and sagittal planes and cut thickness. It was our hypothesis that the use of anatomical landmarks for the tibial cut can help the surgeon to improve accuracy. The technique described in this paper is based on the use of a simple and reproducible anatomical landmark. This landmark is the line of insertion of the fibers of the deep medial collateral ligament (MCL) around the anterior half of the medial tibial plateau called the "Deep MCL insertion line". The used anatomical landmark determines the orientation (in the coronal and sagittal planes) and the thickness of the tibial cut. This landmark corresponds to the line of insertion of the fibers of the deep MCL around the anterior half of the medial tibial plateau. A consecutive series of patients who underwent primary medial UKA between 2019 and 2021 were retrospectively reviewed. A total of 50 UKA were included. The mean age at the time of surgery was 54.5 ± 6.6 years (44-79). The radiographic measurements showed very good to excellent intra-observer and inter-observer agreements. The limb and implant alignments and the tibial positioning were satisfying, with a low rate of outliers and good restoration of the native anatomy. The landmark of the insertion of deep MCL constitutes a reliable and reproducible reference for the tibial cut axis and thickness during medial UKA, independent of the wear severity.

Rehabilitation for total knee replacement (TKA) often involves in-person therapy sessions, which can be time consuming and costly. Digital rehabilitation has the potential to address these limitations, but most of these systems offer standardized protocols without considering the patient's pain, participation, and speed of recovery. Furthermore, most digital systems lack human support in case of need. The aim of this study was to investigate the engagement, safety, and clinical effectiveness of a personalized and adaptative app-based human-supported digital monitoring and rehabilitation program. In this prospective multi-center longitudinal cohort study, 127 patients were included. Undesired events were managed through a smart alert system. Doctors were triggered when there was a suspicion of problems. The drop-out rate, complications and readmissions, PROMS, and satisfaction were collected through the app. There was only 2% readmission. Doctor actions through the platform potentially avoided 57 consultations (85% of alerts). The adherence to the program was 77%, and 89% of the patients would recommend the use of the program. Personalized human-backed-up digital solutions can help to improve the rehabilitation journey of patients after TKA, lower healthcare-related costs by lowering the complication and readmission rate, and improve patient reported outcomes.

The impact of a diaphyseal femoral deformity on knee alignment varies according to its severity and localization. The aims of this study were to determine a method of assessing the impact of diaphyseal femoral deformities on knee alignment for the varus knee, and to evaluate the reliability and the reproducibility of this method in a large cohort of osteoarthritic patients. All patients who underwent a knee arthroplasty from 2019 to 2021 were included. Exclusion criteria were genu valgus, flexion contracture (> 5°), previous femoral osteotomy or fracture, total hip arthroplasty, and femoral rotational disorder. A total of 205 patients met the inclusion criteria. The mean age was 62.2 years (SD 8.4). The mean BMI was 33.1 kg/m 2 (SD 5.5). The radiological measurements were performed twice by two independent reviewers, and included hip knee ankle (HKA) angle, mechanical medial distal femoral angle (mMDFA), anatomical medial distal femoral angle (aMDFA), femoral neck shaft angle (NSA), femoral bowing angle (FBow), the distance between the knee centre and the top of the FBow (DK), and the angle representing the FBow impact on the knee (C'KS angle). The FBow impact on the mMDFA can be measured by the C'KS angle. The C'KS angle took the localization (length DK) and the importance (FBow angle) of the FBow into consideration. The mean FBow angle was 4.4° (SD 2.4; 0 to 12.5). The mean C'KS angle was 1.8° (SD 1.1; 0 to 5.8). Overall, 84 knees (41%) had a severe FBow (> 5°). The radiological measurements showed very good to excellent intraobserver and interobserver agreements. The C'KS increased significantly when the length DK decreased and the FBow angle increased (p < 0.001). The impact of the diaphyseal femoral deformity on the mechanical femoral axis is measured by the C'KS angle, a reliable and reproducible measurement., Competing Interests: C. Batailler reports a grant from Société francaise de chirurgie orthopédique et traumatologique (SoFCOT), and institutional research support from Groupe Lepine, neither of which are related to this study. A. Naaim and J. Daxhelet report no conflicts of interest. S. Lustig reports consulting fees from Stryker, Smith & Nephew, Heraeus, and Depuy Synthes, and institutional research support from Groupe Lepine and Amplitude, all of which are unrelated to this study. S. Lustig is also on the editorial board for The Journal of Bone and Joint Surgery (Am). M. Ollivier reports consulting fees from Arthrex, Stryker, and Newclip technics, unrelated to this study. S. Parratte reports royalties from Zimmer Biomet and Newclip, and consulting fees from Zimmer Biomet, unrelated to this study. S. Parratte is also the treasurer for the European Knee Society., (© 2023 Author(s) et al.)

Background: A new morphometric fixed-bearing unicompartmental knee arthroplasty (UKA) system has been introduced to address the anatomical patient-specific challenges. It was our hypothesis that accurate restoration of the patient-specific anatomy would restore normal knee kinematics after UKA. Therefore, we aimed in this cadaveric study to analyze the impact of a medial morphometric UKA on (1) the varus-valgus and anterior-posterior stability of the knee, (2) the knee kinematics during standardized activities of the daily living, and (3) the patellar tracking, measured using a dedicated robotic testing protocol., Methods: Eight human knee specimens underwent full-leg computed tomography CT scanning and comprehensive robotic assessments of tibiofemoral and patellofemoral kinematics. Specimens were tested in the intact state and after implantation of a fixed-bearing medial UKA. Assessments included passive flexion, laxity testing and simulations of level walking, lunge, and stair descent., Results: Medial and lateral joint laxity after UKA closely resembled intact laxity across the full arc of flexion. Anterior-posterior envelope of motion showed a close match between the intact and UKA groups. Net rollback and average laxity were both not statistically different. Simulation of activities of daily living showed a close match in the anterior-posterior motion profile between the medial condyle and lateral condyle. Patellar tilt and medial-lateral shift during knee flexion matched closely between groups., Conclusion: Functional assessment of this UKA system shows nearly identical behavior to the intact knee. Fixed-bearing UKA with morphometric, compartment-specific geometry and precise mechanical instrumentation replicates complex knee balance and kinematics., (© 2022 The Authors.)

Background: Artificial intelligence (AI) is defined as the study of algorithms that allow machines to reason and perform cognitive functions such as problem-solving, objects, images, word recognition, and decision-making. This study aimed to review the published articles and the comprehensive clinical relevance of AI-based tools used before, during, and after knee arthroplasty., Methods: The search was conducted through PubMed, EMBASE, and MEDLINE databases from 2000 to 2021 using the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA)., Results: A total of 731 potential articles were reviewed, and 132 were included based on the inclusion criteria and exclusion criteria. Some steps of the knee arthroplasty procedure were assisted and improved by using AI-based tools. Before surgery, machine learning was used to aid surgeons in optimizing decision-making. During surgery, the robotic-assisted systems improved the accuracy of knee alignment, implant positioning, and ligamentous balance. After surgery, remote patient monitoring platforms helped to capture patients' functional data., Conclusion: In knee arthroplasty, the AI-based tools improve the decision-making process, surgical planning, accuracy, and repeatability of surgical procedures., (© 2022. The Author(s).)

Background: Residual rotatory knee laxity at midterm follow-up after isolated anterior cruciate ligament reconstruction (ACLR) versus ACLR with lateral extra-articular tenodesis (LET) remains an issue., Purpose/hypothesis: To evaluate the outcomes of ACLR with or without additional LET at a minimum 2-year follow-up in patients with preoperative high-grade pivot shift (PS). Our hypothesis was that the addition of LET would decrease the risk of secondary meniscal injury and the presence of residual high-grade PS at follow-up., Study Design: Cohort study; Level of evidence, 3., Methods: A retrospective analysis performed at 3 sports medicine centers identified 266 study patients; all had a high-grade PS (grade 2 or 3) preoperatively and underwent isolated ACLR with or without LET. Four different ACLR techniques were used: single-strand quadrupled semitendinosus (ST4) ACLR without LET (ST4 group; n = 55), ST4 with anatomic LET (ST4+LET group; n = 77), bone-patellar tendon and modified Lemaire LET (BTB+LET group; n = 43), and quadriceps tendon and modified Lemaire LET (QT+LET group; n = 91). At follow-up, we evaluated for the presence of high-grade (grade ≥2) PS. Preoperative meniscal tears and their treatment were recorded., Results: Overall, 185 (69.5%) patients had at least 1 meniscal tear at index surgery. The mean follow-up period was 44.3 months; 47 (17.7%) patients had a new meniscal tear and 64 (24%) patients had a high-grade PS at follow-up. Compared with meniscal repair, significant predictors for high-grade PS at follow-up were meniscectomy (odds ratio [OR] = 2.65 [95% CI, 1.19-5.63]; P = .02) and nonrepair of preoperative meniscal tear (OR = 3.26 [95% CI, 1.27-9.43]; P = .007). The appearance of a new symptomatic meniscal tear was the strongest significant predictor of high-grade PS at follow-up (OR = 4.31 [95% CI, 2.31-8.06]; P < .001). No significant correlation was observed between the addition of LET and the presence of high-grade PS at follow-up., Conclusion: In the current study, 1 in 4 patients with high-grade PS before ACLR with or without LET was at risk of residual rotatory knee laxity at mean 44-month follow-up, regardless of the technique used. Repairing a pre-existing meniscal lesion was more effective than performing LET to decrease the presence of a high-grade PS at follow-up., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: S.P. has received consulting fees from Zimmer Biomet. C.S. has received consulting fees from Zimmer Biomet and Smith & Nephew. N.P. has received consulting fees from Zimmer Biomet and Smith & Nephew. M.O. has received consulting fees from Arthrex, Stryker, and Newclip. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)