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Mako Robotic Arm-Assisted Unicompartmental Knee Arthroplasty
No full textThe Mako [Mako Surgical Corp. (Stryker), Fort Lauderdale, FL, USA] robotic arm-assisted (RA) unicompartmental knee arthroplasty (UKA) enables the surgeon to perform resurfacing partial knee replacement adapting implant placement to the patient’s anatomy before bone preparation with higher accuracy, reproducibility and survivorship than conventional UKA. This robotic system allows three UKA procedures: medial, lateral, and patello-femoral partial knee replacement. A three-dimensional reconstruction is processed from a lower limb CT scan of the patient and is used for preoperative and intraoperative planning. Using a navigation-based system established on infrared optical arrays, with stable sensors fixed to the patient’s femur and tibia, the surgeon is able to perform surgery with the assistance of a robotic arm that provides neurosensory haptic feedback for bone preparation. This system is based on the concept of patient-specific knee arthroplasty, based on the patient’s anatomy, allowing the surgeon to avoid overcorrection and components’ malalignment during implant placement. The sequence of five phases is the base of every Mako RA-UKA: system setting, preoperative planning and surgical setting, system registration, intraoperative planning and soft-tissue balancing, and finally haptically controlled bone preparation
Total knee arthroplasty in-vivo kinematics changes after insert replacement for posterior cruciate ligament deficiency: a case report
No full textIn cruciate-retaining (CR) total knee arthroplasty (TKA) the preservation of the posterior cruciate ligament (PCL) provides joint stability and drives knee kinematics. No previous studies described in-vivo knee kinematics of PCL-deficient CR TKA. In the present case report it's described the in-vivo kinematic pattern change in a patient with post-operative PCL failure before and after insert replacement to a cruciate substituting (CS) design. In-vivo fluoroscopic analysis showed that PCL-deficient TKA showed more anterior translation of the lateral femoral condyle with respect to a cohort of patients operated of CR-TKA with intact PCL, undergoing fluoroscopic analysis. The replacement to a CS design provided more external rotation of the femoral component and less anterior motion of the lateral condyle. The antero-posterior translation of the medial condyle was similar in PCL-deficient knee, CS TKA and controls. TKA with PCL deficiency showed more antero-posterior motion compared to TKAs with intact PCL and this can be source the of instability and a potential factor for patient's dissatisfaction. For this reason surgeons should attentively verify PCL integrity when performing a cruciate-sparing TKA
Navigated, soft tissue-guided total knee arthroplasty restores the distal femoral joint line orientation in a modified mechanically aligned technique
No full textPurpose: To investigate the femoral component alignment in patients undergoing soft tissue-guided, navigated total knee arthroplasty (TKA). It was hypothesized that with a mechanically aligned tibial component, the soft tissues tensioned and symmetric medial and lateral gaps in flexion/extension, the femoral component would be aligned to the preoperative distal femoral joint line, as measured on knee radiographs. Methods: Between 2015 and 2017, 77 patients (78 knees) underwent navigated soft tissue-guided TKA at a single centre. Pre and postoperative radiographs were collected and varus knees were taken into account. The tibial cut was performed with navigation in neutral alignment. The femoral cuts were adjusted based on tensioned soft tissues, aiming for equal medial and lateral gaps in flexion and extension. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and Knee Society Score (KSS) were collected pre and postoperatively as a secondary outcome measure. Results: A total of 58 TKAs on varus knees were assessed. On average, the femoral component was placed at 1.7° (SD 1.7) varus in the coronal plane. The comparison between the radiographic native distal femoral alignment and the orientation of the femoral component coronal cut demonstrated a statistically significant (p < 0.0001), linear inverse relationship (r = 0.5). Satisfactory knee function and excellent pain remission were demonstrated by KOOS and KSS scores at a mean of 2.8 years (SD 0.5) follow-up. One TKA was revised, resulting in a 98.3% survivorship at three years. Conclusion: The proposed soft tissue-guided, navigated technique, aiming to preserve the integrity of the ligaments and a neutrally aligned tibial cut, provided a joint line respecting femoral coronal cut and encouraging short-term clinical results. Level of evidence: III
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
Robotic arm-assisted unicompartmental knee arthroplasty: high survivorship and good patient-related outcomes at a minimum five years of follow-up
No full textPurpose: Robotic arm-assisted unicompartmental knee arthroplasty (RA-UKA) has been shown to improve component placement, reduce intraoperative variability, increase patient satisfaction and improve short-term survivorship results. The aim of this retrospective study was to determine the incidence of revision and the clinical performance at a minimum of 5-year follow-up for a cohort of patients who received a medial RA-UKA. Methods: Between April 2011 and July 2013, a total of 254 patients underwent medial RA-UKA at a single centre. Clinical performance was investigated using the Forgotten Joint Score-12 (FJS-12) and a 5-level Likert scale made of five items to assess joint perception and patient satisfaction. Kaplan–Meier implant survivorship was calculated and reasons for revision were collected. The effect of age, gender and body mass index (BMI) on the probability of reporting high FJS-12 and satisfaction were assessed. Results: After considering exclusion criteria and loss to follow-up, a total of 216 patients (224 medial RA-UKAs) were assessed at a mean 5.9 years of follow-up. Five RA-UKAs underwent implant revision, resulting in an overall Kaplan–Meier survivorship of 97.8%. Unexplained knee pain (0.9%) was the most common reason for RA-UKA revision. Good-to-excellent FJS-12 scores and high satisfaction levels were reported at mid-term follow-up. Male patients had higher probability of having FJS-12 > 90 (p < 0.05) and high satisfaction levels (p < 0.05). Conclusions: RA-UKAs demonstrated high survivorship and good-to-excellent patient-reported outcome measures and satisfaction levels at minimum 5-year follow-up. Results for male patients had improved clinical performance when compared to female subjects. Level of evidence: IV
High return to sport rate in patients undergoing image-based robotic arm assisted unicompartmental knee arthroplasty
No full textIntroduction: This study was aimed to assess the return to sport (RTS) rate in patients who underwent CT-based robotic-assisted unicompartmental knee arthroplasty (RA-UKA) and to evaluate the clinical performance and the assocition between patients’ sport activity levels and Patient Reported Outcome Measures after surgery. Materials and methods: This retrospective study included 218 patients undergoing medial RA-UKA with fixed-bearing implants, performed at a single center between 2014 and 2019. Patients were allocated into two groups based on sport’s practice and were administered the University of California, Los Angeles (UCLA) activity scale, Forgotten Joint Score-12 (FJS-12), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and the 5-Level Likert Scale. Results: A total of 136 patients were included for assessment. The overall RTS rate after surgery was 93.1%. Six subjects who did not practice sport preoperatively, were able to start sport activities after surgery and all patients performing sports preoperatively, returned to same activity level. The mean UCLA and FJS-12 scores in the group of patients practicing sports were significantly higher than in the no-sport group (p < 0.001 and p < 0.05, respectively). Patients who practiced sports were more likely to attain higher FJS-12 and UCLA scores than those who were not performing physical activity. Conclusions: Patients undergoing RA-UKA showed a 93.1% RTS rate after surgery. Differences were detected in terms of postoperative UCLA and FJS-12 scores between patients who performed and who did not practice sport activities after surgery. High levels of postoperative UCLA scores were associated with higher KOOS-JR and patients’ satisfaction
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Preoperative Osteoarthritic Grade Affects Forgotten Joint Status and Patient Acceptable Symptom State After Robotic Arm-Assisted Unicompartmental Knee Arthroplasty
No full textBackground: This retrospective observational study was designed to investigate the association between radiographic Ahlbäck osteoarthritis (OA) grade and postoperative joint perception in a cohort of patients undergoing medial robotic arm-assisted unicompartmental knee arthroplasty (RA-UKA), using the Forgotten Joint Status and Patient Acceptable Symptom State (PASS) as outcomes. Methods: Between January 2014 and May 2019, 660 patients (719 knees) underwent medial RA-UKA at 2 centers. Ahlbäck OA grade was measured on preoperative knee radiographs. Postoperatively, patients were administered the Forgotten Joint Score-12 (FJS-12) and 5-level Likert scale to assess patients’ satisfaction. Correlations were described among FJS-12, satisfaction, and Ahlbäck OA grade by means of logistic regression models. Results: A total of 547 patients (602 knees) were assessed at a mean follow-up of 3.5 years (standard deviation 1.4). A total of 293 cases were graded as Ahlbäck 1 (Group A) and 309 knees were graded as Ahlbäck>1 (Group B). Statistically significant difference was detected in mean FJS-12 (P < .001), but not in the postoperative satisfaction level (P = .06) between the 2 groups. Patients in Group B had a significantly higher probability of attaining a “forgotten knee” after the operation, compared to Group A (P < .05). Cases in Group A had a significantly lower probability of achieving the PASS (P < .01). Conclusion: Patients with higher grades of OA (Ahlbäck>1) were more likely to attain a “forgotten knee,” while patients with less severe OA (Ahlbäck 1) were less likely to achieve the PASS after RA-UKA. Although patients with less severe OA reported fairly good outcome, cases in which the results will be poorer are currently difficult to predict
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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