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Dive into the research topics where Youichi Yasui is active.

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Featured researches published by Youichi Yasui.


American Journal of Sports Medicine | 2017

Lesion Size Is a Predictor of Clinical Outcomes after Bone Marrow Stimulation for Osteochondral Lesions of the Talus: A Systematic Review

Laura Ramponi; Youichi Yasui; Christopher D. Murawski; Richard D. Ferkel; Christopher W. DiGiovanni; Gino M. M. J. Kerkhoffs; James Calder; Masato Takao; Francesca Vannini; Woo Jin Choi; Jin Woo Lee; James R. Stone; John G. Kennedy

Background: The critical lesion size treated with bone marrow stimulation (BMS) for osteochondral lesions of the talus (OLTs) has been 150 mm2 in area or 15 mm in diameter. However, recent investigations have failed to detect a significant correlation between the lesion size and clinical outcomes after BMS for OLTs. Purpose: To systematically review clinical studies reporting both the lesion size and clinical outcomes after BMS for OLTs. Study Design: Systematic review. Methods: A systematic search of the MEDLINE and EMBASE databases was performed in March 2015 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies were evaluated with regard to the level of evidence (LOE), quality of evidence (QOE), lesion size, and clinical outcomes. Results: Twenty-five studies with 1868 ankles were included; 88% were either LOE 3 or 4, and 96% did not have good QOE. The mean area was 103.8 ± 10.2 mm2 in 20 studies, and the mean diameter was 10.0 ± 3.2 mm in 5 studies. The mean American Orthopaedic Foot and Ankle Society score improved from 62.4 ± 7.9 preoperatively to 83.9 ± 9.2 at a mean 54.1-month follow-up in 14 studies reporting both preoperative and postoperative scores with a mean follow-up of more than 2 years. A significant correlation was found in 3 studies, with a mean lesion area of 107.4 ± 10.4 mm2, while none was reported in 8 studies, with a mean lesion area of 85.3 ± 9.2 mm2. The lesion diameter significantly correlated with clinical outcomes in 2 studies (mean diameter, 10.2 ± 3.2 mm), whereas none was found in 2 studies (mean diameter, 8.8 ± 0.0 mm). However, the reported lesion size measurement method and evaluation method of clinical outcomes widely varied among the studies. Conclusion: An assessment of the currently available data does suggest that BMS may best be reserved for OLT sizes less than 107.4 mm2 in area and/or 10.2 mm in diameter. Future development in legitimate prognostic size guidelines based on high-quality evidence that correlate with outcomes will surely provide patients with the best potential for successful long-term outcomes.


Foot & Ankle International | 2016

Autologous Osteochondral Transplantation for Osteochondral Lesions of the Talus

Seán Flynn; Keir A. Ross; Charles P. Hannon; Youichi Yasui; Hunter Newman; Christopher D. Murawski; Timothy W. Deyer; Huong T. Do; John G. Kennedy

Background: Autologous osteochondral transplantation (AOT) is used to treat osteochondral lesions (OCLs) of the talus, typically reserved for lesions greater than 150 mm2. Few studies exist examining the functional and magnetic resonance imaging (MRI) outcomes following this procedure. The purpose of this study was to investigate functional and MRI outcomes, including quantitative T2 mapping following AOT. Methods: Eighty-five consecutive patients who underwent AOT were identified. Functional outcomes were assessed pre- and postoperatively using the Foot and Ankle Outcome Score (FAOS). The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was used to assess cartilage incorporation. Quantitative T2 MRI relaxation time of graft tissue and adjacent normal cartilage values were recorded in a subset of 61 patients. The mean clinical follow-up was 47.2 months, with mean MRI follow-up of 24.8 months. Results: Mean FAOS improved pre- to postoperatively from 50 to 81 (P < .001). The mean MOCART score was 85.8. Lesion size was negatively correlated with MOCART score (r = −0.36, P = .004). Superficial T2 values in graft tissue were higher than control tissue (42.0 vs 35.8, P < .001). Deep T2 values in graft tissue were similar to the control values (30.9 vs 30.0, P = .305). Functional outcomes were similar in patients irrespective of whether they had previous microfracture or concomitant procedures. Conclusion: AOT was an effective treatment for large OCLs of the talus in the current study. MOCART scoring indicated good structural integrity of the graft. Quantitative T2 mapping suggests that graft tissue may not always mirror native hyaline cartilage. The long-term implications of this are not yet known. Level of Evidence: Level IV, case series.


Knee Surgery, Sports Traumatology, Arthroscopy | 2016

Anatomy of the inferior extensor retinaculum and its role in lateral ankle ligament reconstruction: a pictorial essay.

Miki Dalmau-Pastor; Youichi Yasui; James Calder; Jessica Karlsson; Gino M. M. J. Kerkhoffs; John G. Kennedy

The inferior extensor retinaculum (IER) is an aponeurotic structure, which is in continuation with the anterior part of the sural fascia. The IER has often been used to augment the reconstruction of the lateral ankle ligaments, for instance in the Broström–Gould procedure, with good outcomes reported. However, its anatomy has not been described in detail and only a few studies are available on this structure. The presence of a non-constant oblique supero-lateral band appears to be important. This structure defines whether the augmentation of the lateral ankle ligaments reconstruction is performed using true IER or only the anterior part of the sural fascia. It is concluded that the use of this structure will have an impact on the resulting ankle stability.


Foot & Ankle International | 2016

Clinical and MRI Donor Site Outcomes Following Autologous Osteochondral Transplantation for Talar Osteochondral Lesions

Ethan J. Fraser; Ian Savage-Elliott; Youichi Yasui; Jakob Ackermann; Geoffrey Watson; Keir A. Ross; Timothy W. Deyer; John G. Kennedy

Background: Autologous osteochondral transplantation (AOT) has an inherent risk of donor site morbidity (DSM). The reported rates of DSM vary from 0% to 50%, with few studies reporting clinical or imaging outcomes at the donor site as a primary outcome and even fewer report these outcomes when a biosynthetic plug backfill is employed. Although TruFit (Smith & Nephew, Andover, MA) plugs have been removed from the market for regulatory purposes, biphasic plugs (including TruFit plugs) have been used for several years and the evaluation of these is therefore pertinent. Methods: Thirty-nine patients who underwent forty AOT procedures of the talus, with the donor graft being taken from the ipsilateral knee, were included. Postoperative magnetic resonance imaging (MRI) was used to assess the donor site graded with magnetic resonance observation of cartilage repair tissue (MOCART) scoring. Lysholm scores were collected preoperatively, at the time of magnetic resonance imaging (MRI), and again at 24 months and at final follow-up to assess clinical outcomes. Statistical analysis was performed to establish if there was any correlation between MRI assessment of the donor site and clinical outcomes. The mean patient age was 36.2 ± 15.7 years with a mean follow-up of 41.8 ± 16.7 months. Results: All patient donor site defects were filled with OBI TruFit biphasic plugs. DSM was encountered in 12.5% of the patient cohort at 24 months, and in these patients, the Lysholm score was a mean 87.2 ± 5.0. At final follow-up, DSM was reduced to 5%. Lysholm scores for the entire cohort were 98.4 ± 4.6 and 99.4 ± 3.1 at 24 months and final follow-up, respectively. MRI of the donor sites were taken at an average of 18.1 ± 13.5 (range, 3-48) months postoperatively and the mean MOCART score was 60.0 ± 13.5. No correlation was found between the MOCART score and Lysholm outcomes at the donor knee (P = .43, r = 0.13). Conclusion: Low incidence of DSM and good functional outcomes were achieved with AOT. Additionally, MRI findings did not predict clinical outcomes in our study. Level of Evidence: Level IV, retrospective case series.


Knee Surgery, Sports Traumatology, Arthroscopy | 2016

Functional outcomes after peroneal tendoscopy in the treatment of peroneal tendon disorders

John G. Kennedy; Pim van Dijk; Christopher D. Murawski; Gavin L. Duke; Hunter Newman; Christopher W. DiGiovanni; Youichi Yasui

AbstractPurposenThe primary purpose of this study was to evaluate clinical outcomes following peroneal tendoscopy for the treatment of peroneal pathology. Correlation between pre-operative magnetic resonance imaging (MRI) and peroneal tendoscopic diagnostic findings was also assessed.MethodsTwenty-three patients with a mean age of 34xa0±xa08.8xa0years undergoing peroneal tendoscopy were pre- and post-operatively assessed with the foot and ankle outcome score (FAOS) and the Short Form-12 (SF-12) outcome questionnaires. Follow-up was over 24xa0months in all patients. The sensitivity and specificity of MRI were calculated in comparison with peroneal tendoscopy, including the positive predictive value (PPV).ResultsBoth the FAOS and the SF-12 improved significantly (pxa0<xa00.05) at a mean follow-up of 33xa0±xa07.3xa0months significantly. MRI showed an overall sensitivity of 0.90 (95xa0% confidence interval (CI)xa0=xa00.82–0.95) and specificity of 0.72 (95xa0% CI 0.62–0.80). The PPV for MRI diagnosis of peroneal tendon pathology was 0.76 (95xa0% CI 0.68–0.83).ConclusionsThe current study found good clinical outcomes in patients with peroneal tendon disorders, treated with peroneal tendoscopy. Although a relatively small number of patients were included, the study suggests good correlation between tendoscopic findings and pre-operative MRI findings of peroneal tendon pathology, supporting the use of MRI as a useful diagnostic modality for suspected peroneal tendon disorders.Level of evidenceLevel IV, retrospective case series.


Arthroscopy | 2016

The Effect of Different Bone Marrow Stimulation Techniques on Human Talar Subchondral Bone: A Micro–Computed Tomography Evaluation

Arianna L. Gianakos; Youichi Yasui; Ethan J. Fraser; Keir A. Ross; Marcelo Pires Prado; Lisa A. Fortier; John G. Kennedy

PURPOSEnTo evaluate morphological alterations, microarchitectural disturbances, and the extent of bone marrow access to the subchondral bone marrow compartment using micro-computed tomography analysis in different bone marrow stimulation (BMS) techniques.nnnMETHODSnNine zones in a 3xa0× 3 grid pattern were assigned to 5 cadaveric talar dome articular surfaces. A 1.00-mm microfracture awl (s.MFX), a 2.00-mm standard microfracture awl (l.MFX), or a 1.25-mm Kirschner wire (K-wire) drill hole was used to penetrate the subchondral bone in each grid zone. Subchondral bone holes and adjacent tissue areas were assessed by micro-computed tomography to analyze adjacent bone area destruction and communicating channels to the bone marrow. Grades 1 to 3 were assigned, where 1xa0= minimal compression/sclerosis; 2xa0=xa0moderate compression/sclerosis; 3xa0= severe compression/sclerosis. Bone volume/total tissue volume, bone surface area/bone volume, trabecular thickness, and trabecular number were calculated in the region of interest.nnnRESULTSnVisual assessment revealed that the s.MFX had significantly more grade 1 holes (P < .001) and that the l.MFX had significantly more poor/grade 3 holes (Pxa0= .002). Bone marrow channel assessment showed a statistically significant increase in the number of channels in the s.MFX when compared with both K-wire and l.MFX holes (P < .001). Bone volume fraction for the s.MFX was significantly less than that of the l.MFX (Pxa0= .029).nnnCONCLUSIONSnBMS techniques using instruments with larger diameters resulted in increased trabecular compaction and sclerosis in areas adjacent to the defect. K-wire and l.MFX techniques resulted in less open communicating bone marrow channels, denoting a reduction in bone marrow access. The results of this study indicate that BMS using larger diameter devices results in greater microarchitecture disturbances.nnnCLINICAL RELEVANCEnThe current study suggests that the choice of a BMS technique should be carefully considered as the results indicate that smaller diameter hole sizes may diminish the amount of microarchitectural disturbances in the subchondral bone.


Journal of Foot & Ankle Surgery | 2016

Open Versus Arthroscopic Ankle Arthrodesis: A Comparison of Subsequent Procedures in a Large Database

Youichi Yasui; Khushdeep S. Vig; Christopher D. Murawski; Payal Desai; Ian Savage-Elliott; John G. Kennedy

Arthroscopic and open ankle arthrodesis have been compared in very few studies, and no consensus has been reached regarding the incidence of postoperative revision surgery associated with each technique. The purpose of the present study was to compare these 2 approaches for the incidence of postsurgical operations. Patients who had undergone either arthroscopic or open ankle arthrodesis were identified between January 2005 to December 2011 in the PearlDiver(™) database using a predetermined algorithm and searched for the following postsurgical operations: revision ankle arthrodesis, midfoot arthrodesis, and hindfoot arthrodesis. Inxa0the current database, 7322 cases were performed with an open technique and 1152 arthroscopically. Thexa0incidence of revision arthrodesis was not significantly different statistically between the 2 techniques. However, the incidence of subsequent adjacent joint arthrodesis was greater for the open cohort (5.6% versus 2.6%; odds ratio 2.17, 95% confidence interval 1.49 to 3.16). In the open cohort, the incidence of hindfoot arthrodesis was greater than the incidence of midfoot arthrodesis (3.9% versus 1.6%, odds ratio 2.43, 95% confidence interval 1.95 to 3.01). The results showed that although open ankle arthrodesis is more commonly performed, it is associated with a greater incidence of subsequent adjacent joint arthrodesis specifically in the hindfoot.


Knee Surgery, Sports Traumatology, Arthroscopy | 2018

Limited evidence for adipose-derived stem cell therapy on the treatment of osteoarthritis

Eoghan T. Hurley; Youichi Yasui; Arianna L. Gianakos; Dexter Seow; Yoshiharu Shimozono; Gino M. M. J. Kerkhoffs; John G. Kennedy

PurposeThe purpose of this systematic review is to evaluate the effects of adipose derived mesenchymal stem cells (ADSCs) in the treatment of osteoarthritis (OA) in the clinical setting.MethodsA literature search was performed in the MEDLINE, EMBASE, and The Cochrane Library Database up to January 2017 for inclusion and exclusion criteria. Criteria for inclusion were clinical studies demonstrating the effects of ADSCs on OA, and written in English. The following variables were analyzed: donor site, volume of adipose tissue, preparation of ADSCs, clinical outcomes, and complication rate.ResultsSixteen studies (knee: 14 studies, multiple joints: 1 study, ankle: 1 study) were included in this systematic review. All of the studies prepared ADSCs in the form of the stromal vascular fraction (SVF). Inconsistencies between studies were found with regards to reported clinical variability, donor sites of SVF, and reported clinical outcomes. Nine studies used either platelet-rich plasma (PRP) (7/16) or fibrin (4/16) or both PRP and Fibrin (1/16), as an adjunct at time of SVF injection. All of the studies reported an improvement in clinical outcomes with the use of SVF. Five studies reported a 90% satisfaction rate, and no study reported any complications with liposuction. Five studies reported on complications, with a 5% incidence of swelling and pain.ConclusionsThis systematic review demonstrated that ADSCs are currently used in the form of SVF. While SVF may produce favorable clinical outcomes with minimal risk of side effects on osteoarthritis, the variability in the data and the use of biological adjuvants have confounded the effectiveness of ADSCs. This study will help surgeons understand the limitations in the literature on ADSCs.Level of evidenceLevel IV, systematic review of level IV studies.


International Orthopaedics | 2017

Use of the arthroereisis screw with tendoscopic delivered platelet-rich plasma for early stage adult acquired flatfoot deformity

Youichi Yasui; Ichiro Tonogai; Andrew J. Rosenbaum; David Moore; Masato Takao; Hirotaka Kawano; John G. Kennedy

PurposeEarly stage adult acquired flatfoot deformity (AAFD) is traditionally treated with osteotomy and tendon transfer. Despite a high success rate, the long recovery time and associated morbidity are not sufficient. This study aims to evaluate the functional and radiological outcomes following the use of the arthroereisis screw with tendoscopic delivered PRP for early stage AAFD.MethodsPatients with stage IIa AAFD who underwent the use of the arthroereisis screw with tendoscopic delivered PRP with a minimum follow-up time of 24xa0months were retrospectively evaluated. Clinical outcomes for pain were evaluated with the Foot and Ankle Outcomes Score (FAOS) and Visual Analog Score (VAS). Radiographic deformity correction was assessed using weight-bearing imaging.ResultsThirteen patients (13 feet) with mean follow-up of 29.5u2009months were included. The mean age was 37.3u2009years (range, 28–65xa0years). FAOS-reported symptoms, pain, daily activities, sports activities, and quality of life significantly improved from 52.1, 42.6, 57.6, 35.7, and 15.4 pre-operatively to 78.5, 68.2, 83.3, 65.0, and 49.6 post-operatively, respectively (pu2009<u20090.05). Statistically significant radiographic improvements (lateral talus first metatarsal angle, calcaneal pitch, and cuneiform to ground distance) were also observed between the pre- and post-operative images.ConclusionsThis study elucidates the successful implementation of a less invasive approach to stage IIa AAFD. Through the use of a subtalar arthroereisis screw, PTT tendoscopy, and PRP injection, clinical and radiographic outcomes were improved.


Cartilage | 2017

Operative Treatment for Osteochondral Lesions of the Talus Biologics and Scaffold-Based Therapy

Youichi Yasui; Adi Wollstein; Christopher D. Murawski; John G. Kennedy

Objective Numerous basic science articles have published evidence supporting the use of biologic augmentation in the treatment of osteochondral lesions of the talus (OLT). However, a comprehensive evaluation of the clinical outcomes of those treatment modalities in OLT has yet to be published. The purpose of this review is to provide an evidence-based overview of clinical outcomes following biologic augmentation to surgical treatments for OLT. Design A comprehensive literature review was performed. Two commonly used surgical techniques for the treatment of OLT—bone marrow stimulation and osteochondral autograft transfer—are first introduced. The review describes the operative indications, step-by- step operative procedure, clinical outcomes, and concerns associated with each treatment. A review of the currently published basic science and clinical evidence on biologic augmentation in the surgical treatments for OLT, including platelet-rich plasma, concentrated bone marrow aspirate, and scaffold-based therapy follows. Results Biologic agents and scaffold-based therapies appear to be promising agents, capable of improving both clinical and radiological outcomes in OLT. Nevertheless, variable production methods of these biologic augmentations confound the interpretation of clinical outcomes of cases treated with these agents. Conclusions Current clinical evidence supports the use of biologic agents in OLT cases. Nonetheless, well-designed clinical trials with patient-specific, validated and objective outcome measurements are warranted to develop standardized clinical guidelines for the use of biologic augmentation for the treatment of OLT in clinical practice.

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John G. Kennedy

Hospital for Special Surgery

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Adi Wollstein

University of Pittsburgh

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Andrew W. Ross

Hospital for Special Surgery

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Arianna L. Gianakos

Hospital for Special Surgery

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Keir A. Ross

Hospital for Special Surgery

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Dexter Seow

Royal College of Surgeons in Ireland

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Eoghan T. Hurley

Royal College of Surgeons in Ireland

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