1,720,976 research outputs found
Navigation-assisted total knee arthroplasty in knees with osteoarthritis due to extra-articular deformity.
No full textPURPOSE:
Extra-articular post-traumatic deformity may make difficult the implantation of total knee arthroplasty (TKA). Staged surgical procedures, including femoral or tibial osteotomy, can be required to restore proper alignment. These procedures may be inappropriate because of high rate of complications. Intra-articular resection is an alternative procedure, but it is limited by the potential compromise of collateral knee ligaments. Conventional instrumentation cannot be used in patients with previous trauma and residual bone deformity. We want to assess whether computer-assisted surgery may be a good alternative to traditional techniques.
METHODS:
Twenty consecutive TKAs were performed in 20 patients (12 men and 8 women) with knee arthritis due to extra-articular deformity. The mean age was 52 years. According to Moreland method, the mean (± standard deviation) of the pre-operative hip-knee-ankle angle was 10.4° ± 8.3° in varus. In all cases, an image-free knee navigation system was used because of the severe deformity or the presence of retained hardware that prevented the use of the intramedullary rod. The average follow-up was 3.1 years.
RESULTS:
One month after surgery, the mean hip-knee-ankle angle was 0.8° ± 1.2° in varus. At follow-up, the Knee Society Score increased from an average of 48 pre-operatively to 91 (P < 0.05) post-operatively, with over 90% of excellent and good results. Mean range of motion improved from a 7°-74° mean range pre-operatively to 0°-94° post-operatively.
CONCLUSIONS:
The general value of navigation systems in achieving accurate bone cuts and restoring the mechanical axis has been established in the literature for standard TKA but not yet for extra-articular deformity. Our findings at mid-term follow-up on a large cohort of these patients showed that these systems used for intra-articular resection are a very effective alternative to previous techniques
Can TKA design affect the clinical outcome? Comparison between two guided-motion systems.
No full textIn a retrospective comparative analysis in patients undergoing primary guided-motion total knee arthroplasty (TKA), the authors have evaluated whether different TKA implant design would influence the clinical and functional outcomes.
METHODS:
Between 2007 and 2009, 227 computer-assisted primary TKAs were performed in 219 consecutive patients. Patients received one of the two different fixed-bearing guided-motion TKA designs assisted by navigation surgery: the Scorpio Non-Restrictive Geometry (NRG) knee system and the Journey Bi-Cruciate Stabilized (BCS) knee systems.
RESULTS:
Data were available for 180 patients (187 knees). No significant differences were observed between the two groups with respect to preoperative demographic characteristics, range of motion (ROM) and radiographic knee alignment. At a mean follow-up of 29 months, the Journey BCS group had higher mean Knee Injury and Osteoarthritis Outcome Score (KOOS) in all subscales and a greater ROM than the Scorpio NRG group. This difference was statistically significant for the KOOS subscales of pain (p = 0.007) and knee-related quality of life (p = 0.045), as well as for postoperative ROM (p = 0.018). Considering the overall complications, 1 patient of Scorpio NRG group (0.5%) and 5 in Journey BCS (2.7%) had stiffness. Anterior knee pain was reported in 4 cases of Scorpio NRG group (2.1%). In the Journey BCS group were observed 2 cases (1.1%) of frontal plane instability and 1 case (0.5%) of synovitis pain.
CONCLUSIONS:
The bearing geometry and kinematic pattern of different guided-motion prosthetic designs can affect the clinical-functional outcome and complications type in primary TKA.
LEVEL OF EVIDENCE:
Clinical study, Level III
UKA: Standard
No full textUnicompartmental knee arthroplasty (UKA) has encountered a growing interest of the orthopedic community since its introduction in the first years of 1970s (UKA). The long-term outcome of UKA depends on patient selection, age, gender, and level of activity [18, 22, 25]. Despite satisfying clinical and radiological outcomes of UKAs procedures [26, 46, 47], many cases with need for further intervention were also reported [38]. Polyethylene implant failure [2, 29, 39], deterioration of the lateral compartment within a few years following the UKA, pain in the contralateral or patellofemoral compartment [5], and aseptic loosening [31] could affect implant survival
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
How to improve femoral component rotational alignment in computer-assisted TKA
No full textPurpose: Although several anatomical landmarks have been proposed to obtain adequate femoral component alignment in total knee arthroplasty (TKA), there is still no consensus regarding the best way to correctly position the prosthetic component on the horizontal plane. A previous computed tomography (CT)-based study has demonstrated anatomical transepicondylar axis (aTEA) to be externally rotated relative to surgical transepicondylar axis (sTEA) of approximately 4.5°. In this study, it is described a new methodological approach to femoral component rotational positioning through the use of previously reported CT scan information and navigation. Methods: Eight consecutive patients scheduled for navigated TKA were selected. Rotational placement of the femoral component was performed using navigation system. The femoral component was implanted setting 4.5° of internal rotation relative to the aTEA. Within 1 week from surgery, all patients underwent a CT scan, and the posterior condylar angle (PCA) was measured. A PCA of 0.0°, meaning component placement parallel to sTEA, was set as femoral rotational alignment target. Clinical evaluation was performed at a mean 14.3 months of follow-up with KOOS questionnaire. Results: The mean PCA measured on post-operative CT images was 0.4° (SD 1.3°), meaning that the femoral component was averagely implanted with 0.4° of internal rotation relative to the sTEA. Seven out of eight cases (87.5 %) resulted to have within 1° deviation from the rotational alignment target. All patients but one reported good clinical results. Conclusions: Relevant finding of the present study was that the use of navigation and aTEA as a reference demonstrated to be accurate to set up femoral component rotational positioning on the horizontal plane in TKA. Further study should be performed to confirm this conclusion. Level of evidence: III. © 2014 Springer-Verlag Berlin Heidelberg
In vivo kinematics of medial unicompartmental osteoarthritic knees during activities of daily living
No full textFew studies exist describing unicompartmental osteoarthritic knee kinematics. Moreover, the role of the anterior cruciate ligament (ACL) in the determination of knee kinematics has not been fully described. The objective of the current study was to analyze the in vivo kinematics of knees with medial osteoarthritis (OA) and intact ACL during closed and open chained motion. Eight patients scheduled for UKA diagnosed with primary medial OA underwent knee CT-scans and video-fluoroscopy. Fluoroscopic analysis included stair climbing, chair rising and leg extension. Three-dimensional bone positions were obtained from each image by iterative procedures using a CAD-model-based shape-matching technique. Patterns of axial rotation and anterior-posterior (AP) motion of the medial and lateral femoral condyle were obtained with specific software. The femur reported an overall external rotation relative to the tibia from extension to flexion in all tasks. Average AP translation of the medial femoral condyle were smaller in open-chained tasks than in weight-bearing conditions. Average AP motion of the lateral femoral condyle reported an overall posterior translation with knee flexion. The absent natural "screw-home" mechanism and the lack of medial condyle posterior translation was explained by bone-cartilage defects and meniscal degeneration. Relevant findings were the kinematic pattern differences between weight-bearing and open chained activities, suggesting that in biphasic muscle contraction and unloaded conditions, the function of the cruciate ligaments was not physiological. The kinematics of knees with medial OA and intact ACL differed from healthy knees.Few studies exist describing unicompartmental osteoarthritic knee kinematics. Moreover, the role of the anterior cruciate ligament (ACL) in the determination of knee kinematics has not been fully described. The objective of the current study was to analyze the in vivo kinematics of knees with medial osteoarthritis (OA) and intact ACL during closed and open chained motion. Eight patients scheduled for UKA diagnosed with primary medial OA underwent knee CT-scans and video-fluoroscopy. Fluoroscopic analysis included stair climbing, chair rising and leg extension. Three-dimensional bone positions were obtained from each image by iterative procedures using a CAD-model-based shape-matching technique. Patterns of axial rotation and anterior-posterior (AP) motion of the medial and lateral femoral condyle were obtained with specific software.The femur reported an overall external rotation relative to the tibia from extension to flexion in all tasks. Average AP translation of the medial femoral condyle were smaller in open-chained tasks than in weight-bearing conditions. Average AP motion of the lateral femoral condyle reported an overall posterior translation with knee flexion.The absent natural "screw-home" mechanism and the lack of medial condyle posterior translation was explained by bone-cartilage defects and meniscal degeneration. Relevant findings were the kinematic pattern differences between weight-bearing and open chained activities, suggesting that in biphasic muscle contraction and unloaded conditions, the function of the cruciate ligaments was not physiological. The kinematics of knees with medial OA and intact ACL differed from healthy knees
Surgeon’s experience influences UKA survivorship: a comparative study between all-poly and metal back designs
No full textPurpose: Concerns exist regarding prosthetic positioning and post-operative limb alignment in unicompartmental knee arthroplasty (UKA). In this study, we hypothesized deviations of the post-op anatomical femoro-tibial angle (aFTA) and the tibial component alignment to be factors influencing UKA survivorship. Moreover, by a comparison between all-poly and metal back UKAs, we hypothesized that prosthetic design plays a role in implant survivorship. Methods: One hundred ninety-five medial UKAs were performed on 176 patients by two experienced surgeons and one low-UKA user. One hundred and forty-seven UKAs were included in the study: 72 all-poly and 75 metal back. Measurements were performed on radiographs: mechanical femoro-tibial angle, Cartier angle, aFTA and tibial posterior slope (PS) on pre-op radiographs; femoral and tibial component varus/valgus, aFTA and tibial component PS on post-op radiographs. Results: At an average follow-up of 61 months (min. 30, max. 107), 147 UKAs were evaluated: The reported survivorship rate was 93.1 %. Eleven implants underwent revision: ten all-poly and one metal back. No differences were reported between the two groups in the radiographic measurements. Significant radiographic differences were reported between revised and not revised UKAs: Revised UKAs were associated with overcorrection of the pre-op Cartier angle and under correction of pre-op aFTA. Most of revised UKAs were performed by the low-volume UKA surgeon. Conclusions: Surgeon’s experience is essential to achieve good results in UKA: Preserving the tibial epiphyseal axis and avoiding excessive or insufficient corrections of the pre-operative limb alignment are predictor of successful replacement, while prosthetic designs, models and fixation geometry do not affect UKA outcome. Level of evidence: IV
Unicompartmental knee arthroplasty has higher revisions than total knee arthroplasty at long term follow-up: a registry study on 6453 prostheses
Full text linkPurpose: The purpose of this study is to analyse long-term unicompartmental knee arthroplasty (UKA) focusing on survivorship, causes of failure and revision strategy.
Methods: This study is a retrospective analysis of data from a regional arthroplasty registry for cases performed between 2000 and 2017. A total of 6453 UKAs were identified and the following information was analysed: demographic data, diagnosis leading to primary implant, survivorship, complication rate, causes of failure, revision strategies. UKA registry data were compared with total knee arthroplasty (TKA) registry data of 54,012 prostheses, which were implanted in the same time period.
Results: 6453 UKAs were included in the study: the vast majority of them (84.4%) were implanted due to primary osteoarthritis followed by deformity (7.1%) and necrosis of the condyle (5.1%). When compared to TKA, UKA showed lower perioperative complication rate (0.3% compared to 0.6%) but higher revision rate (18.2% at 15 years, compared to 6.2% for TKA). No correlation was found between diagnosis leading to primary implant and prosthesis survival. The most frequent cause of failure was total aseptic loosening (37.4%), followed by pain without loosening (19.8%). Of the 620 UKAs requiring revision, 485 were revised with a TKA and 61 of them required a re-revision; on the other hand, of the 35 cases where another UKA was implanted, 16 required a re-revision.
Conclusion: UKA is associated with fewer perioperative complications but higher revision rates when compared to TKA. Its survivorship is not affected by the diagnosis leading to primary implant. Revision surgery of a failed UKA should be performed implanting a TKA, which is associated with a lower re-revision rate when compared to another UKA
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