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Dive into the research topics where Yu Ozaki is active.

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Featured researches published by Yu Ozaki.


Journal of orthopaedic surgery | 2017

Spontaneous healing of lateral femoral cutaneous nerve injury and improved quality of life after total hip arthroplasty via a direct anterior approach: Survey at average 12.8 and 26.2 months of follow-up

Yu Ozaki; Yasuhiro Homma; Tomonori Baba; Kei Sano; Asuka Desroches; Kazuo Kaneko

Purpose: How the symptomatology of lateral femoral cutaneous nerve (LFCN) injury changes after total hip arthroplasty (THA) via direct anterior approach (DAA) is not known. Our hypothesis was that the symptoms of LFCN injury after THA via DAA in longer follow-up periods would resolve spontaneously, leading to an improved quality of life (QOL). The aims of this study were to investigate how the symptom LFCN injury changed after DAA–THA, and how those changes affected QOL. Methods: We investigated the incidence of LFCN injury after DAA–THA using self-reported questionnaires at two time points (initial survey: August 2014, present survey: August 2015). QOL was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire, and the Forgotten Joint Score-12 (FJS-12). Types (dysesthesia or hypesthesia) and changes of the symptom were surveyed. Results: About 122 hips at average12.8 months postoperatively (initial survey), and of those, 89 hips at average 26.2 months postoperatively (present survey) were analyzed. The incidence of LFCN injury decreased significantly, from 31.9% to 11.2% (p < 0.001). Spontaneous improvement of symptoms was seen in 96%. The difference of FJS-12 between patients with and without LFCN injury at the initial survey disappeared at the present survey. The dysesthesia group showed significant correlations between rate of improvement in LFCN injury and increase of QOL. Conclusion: Most symptoms of LFCN injury resolved spontaneously with longer follow-up periods. In particular, improvement of dysesthesia as a symptom of LFCN injury was associated with better QOL.


SICOT-J | 2017

Kerboull-type plate in a direct anterior approach for severe bone defects at primary total hip arthroplasty: technical note

Mikio Matsumoto; Tomonori Baba; Hironori Ochi; Yu Ozaki; Taiji Watari; Yasuhiro Homma; Kazuo Kaneko

Introduction: For cases with extensive acetabular bone defects, we perform surgery combining the Kerboull-type (KT) plate and bone graft through direct anterior approach (DAA) in primary total hip arthroplasty (THA) requiring acetabular reconstruction as minimally invasive surgery. This paper provides the details of the surgical procedure. Methods: The basic structure of the Kerboull-type plate is a cruciform plate. Since the hook of the Kerboull-type plate has to be applied to the tear drop, a space for it was exposed. The tear drop is located in the anterior lower region in surgery through DAA in supine position. It was also confirmed by fluoroscopy as needed. The bone grafting was performed using an auto- or allogeneic femoral head for bone defects in the weight-bearing region of the hip joint. Results: Of 563 patients who underwent primary THA between 2012 and 2014, THA using the KT plate through DAA was performed in 21 patients (3.7%). The mean duration of postoperative follow-up was 31.8 months. The mean operative time was 188.4 min, and the mean blood loss was 770 g. The patients became able to walk independently after 2.4 days on average (1–4 days). On clinical evaluation, the modified Harris Hip Score was 45.6 ± 12.4 before surgery, and it was significantly improved to 85.3 ± 8.97 on the final follow-up. Discussion: DAA is a true intermuscular approach capable of conserving soft tissue. Since it is applied in a supine position, fluoroscopy can be readily used, and it was very useful to accurately place the plate.


International Orthopaedics | 2017

In total hip arthroplasty via the direct anterior approach, a dual-mobility cup prevents dislocation as effectively in hip fracture as in osteoarthritis

Yasuhiro Homma; Tomonori Baba; Yu Ozaki; Taiji Watari; Hideo Kobayashi; Hironori Ochi; Mikio Matsumoto; Kazuo Kaneko

PurposeThe main purpose of this study was to compare the outcome of total hip arthroplasty (THA) via the direct anterior approach (DAA) using a dual-mobility cup (DMC) in patients with femoral neck fracture to those in patients undergoing elective THA for osteoarthritis.Patients and methodsWe retrospectively investigated 40 hips with femoral neck fracture (group A), and 81 hips with osteoarthritis (group B). THA via the DAA using the DMC was performed in both groups. A primary/secondary outcome variable were the presence of dislocation/operative time, intra- and/or peri-operative complication, and mortality.ResultsDislocation did not occur in either group. The complication rate was slightly higher in group A than in group B, but not statistically significant.ConclusionTHA with the DMC using the DAA was as effective for femoral neck facture as it was for elective THA in patients with osteoarthritis.


SICOT-J | 2017

Total hip arthroplasty via the direct anterior approach with a dual mobility cup for displaced femoral neck fracture in patients with a high risk of dislocation

Hironori Ochi; Tomonori Baba; Yasuhiro Homma; Mikio Matsumoto; Taiji Watari; Yu Ozaki; Hideo Kobayashi; Kazuo Kaneko

Introduction: Although total hip arthroplasty (THA) is superior to bipolar hemiarthroplasty (BHA) for displaced femoral neck fracture in terms of hip pain, function and reoperation rate, THA has a higher rate of dislocation. The direct anterior approach (DAA) and a dual mobility cup (DMC) are associated with lower rates of dislocation. The aim of this study was to investigate the outcomes of THA compared with BHA, and in those patients who had a THA we investigated those with a DMC (DMC-THA) and compared them with those had a single conventional cup (Single cup-THA). Materials: A total of 89 patients living independently were included between 2009 and 2015. We assessed patient characteristics, peri- and post-operative outcomes, walking ability and one-year mortality. Adjusted odds ratios (Adjusted ORs) were estimated for decrease of walking ability and one-year mortality using a logistic regression model with adjustment for potential confounders such as age, neuromuscular diseases with weakness, duration of surgery, perioperative blood loss and preoperative walking ability. Results: BHA (20 patients) versus THA (69 patients): There was no significant difference in the walking ability in either group. Multivariable logistic regression analysis demonstrated a significant association with one-year mortality in both groups [THA Adjusted ORs 0.088 (95% CI 0.0007–0.69); p = 0.020]. Single cup-THA (36 patients) versus DMC-THA (33 patients): The DMC-THA group had significantly greater age and more patients with neuromuscular diseases with weakness compared with the Single cup-THA group. Multivariable logistic regression analysis demonstrated no significant difference in the decrease of walking ability and in the one-year mortality between the groups. There were no post operative dislocations in any group. Discussion: THA via the DAA is one of the best treatments for displaced femoral neck fracture with a low risk of dislocation. THA via the DAA with a DMC is a safe and effective treatment for the patients with a high risk of dislocation.


Case reports in orthopedics | 2016

Total Hip Arthroplasty for Implant Rupture after Surgery for Atypical Subtrochanteric Femoral Fracture

Yu Ozaki; Tomonori Baba; Hironori Ochi; Yasuhiro Homma; Taiji Watari; Mikio Matsumoto; Kazuo Kaneko

Treatment methods for delayed union and nonunion of atypical femoral fracture are still controversial. Moreover, no treatment method has been established for implant rupture caused by delayed union and nonunion. We encountered a 74-year-old female in whom nonunion-induced implant rupture occurred after treatment of atypical subtrochanteric femoral fracture with internal fixation using a long femoral nail. It was unlikely that sufficient fixation could be obtained by repeating osteosynthesis alone. Moreover, the patient was elderly and early weight-bearing activity was essential for early recovery of ADL. Based on these reasons, we selected one-stage surgery with total hip arthroplasty and osteosynthesis with inverted condylar locking plate as salvage procedures. Bone union was achieved at 6 months after surgery. This case illustrated that osteosynthesis-combined one-staged total hip arthroplasty could be considered as one of the options for nonunion-induced implant rupture of atypical femoral subtrochanteric fracture.


SICOT-J | 2018

Preoperative ultrasound to identify distribution of the lateral femoral cutaneous nerve in total hip arthroplasty using the direct anterior approach

Yu Ozaki; Tomonori Baba; Yasuhiro Homma; Hiroki Tanabe; Hironori Ochi; Sammy Bannno; Taiji Watari; Kazuo Kaneko

Introduction: Recently, the branching pattern of the lateral femoral cutaneous nerve (LFCN) named Fan type has been reported that LFCN injury cannot be avoided in surgical dissections that use the direct anterior approach to the hip joint in the cadaveric study. We hypothesized that the Fan type can be identified by ultrasound The aim of this study was to investigate whether LFCN injury occurs in DAA-THA in cases identified as the Fan type based on preoperative ultrasound of the proximal femur. Methods: Ultrasonography of the proximal femur on the surgical side was performed before surgery and the LFCN distribution was judged as the Fan type or Non-Fan type. A self-reported questionnaire was sent to the patients at two months after surgery, and the presence or absence of LFCN injury was prospectively surveyed. Results: After application of exclusion criteria, 45 hips were included. LFCN injury was observed after surgery in 9 of the 10 patients judged as the Fan type based on the ultrasound of the proximal femur (positive predictive value: 90%), and no LFCN disorder was actually observed in 25 of the 26 patients judged as Non-Fan type (specificity: 96.2%). Conclusions: To prevent injury of the LFCN in patients judged as the Fan type on the ultrasound test before surgery, the risk of direct injury of the LFCN may be reduced through the approach in which an incision is made in the fascia which is opposite to the radial spreading, i.e., between the sartorius and tensor fasciae latae muscles or slightly medial from it.


European Journal of Orthopaedic Surgery and Traumatology | 2018

The Baba classification focused on implant designs is useful in setting the therapeutic strategy for interprosthetic femoral fracture

Tomonori Baba; Kazuo Kaneko; Yasuhiro Homma; Hironori Ochi; Yu Ozaki; Taiji Watari; Mikio Matsumoto

PurposeThe purpose of this study was to investigate the clinical outcomes of femoral fracture with implants on the proximal and distal sides to verify whether actual fracture morphologies follow the fracture types of Baba classification focusing on implant designs useful for periprosthetic femoral fracture.MethodsProsthesis was present in 85 with periprosthetic femoral fractures. Excluding 73 patients with fracture around the femoral stem or fracture of the TKA femoral component alone, 12 patients with 14 legs with both implants were investigated. All patients were radiographically assessed for implant stability according to the Baba classification. For clinical evaluation, intra- and postoperative complications, the operation time, and intra-operative blood loss were investigated.ResultsThe Baba classification fracture type showed the implant as unstable and stable types in 3 and 11 legs, respectively. The consistency rate between the Baba classification-based judgment of plain radiograms acquired at the time of injury and actual surgical findings was 100%. As a result of treatment according to the Baba classification, bone union was achieved in all patients. There were no intra- or postoperative complications.ConclusionsApplying the Baba classification, implant stability could be sufficiently evaluated in not only periprosthetic femoral fractures following hip arthroplasty, but also interprosthetic femoral fractures, thereby verifying its usefulness in setting the treatment strategy.


Case reports in orthopedics | 2017

Safe and Effective Reduction Technique for Intertrochanteric Fracture with Ipsilateral Below-Knee Amputated Limb

Hironori Ochi; Tomonori Baba; Takahiro Hamanaka; Yu Ozaki; Taiji Watari; Yasuhiro Homma; Mikio Matsumoto; Kazuo Kaneko

The positioning of the patient on the fracture table is critical for the successful reduction and operative fixation of intertrochanteric hip fractures. However, this manipulation is challenging with patients who have undergone amputations of their legs. A 97-year-old man presented to the emergency department with symptom of right hip pain following a mechanical fall. He had a below-knee amputation on his right leg following a traffic accident as a 19-year-old and had a below-knee patellar tendon bearing prosthesis fitted to his lower limb for mobility. Radiographs of his pelvis revealed a displaced intertrochanteric fracture of the right side femur. The patient was positioned on a fracture table, as in the standard procedure. The method of inverting the traction boot to accommodate the flexed knee and stump described by Al-Harthy could be used to provide traction and rotational control. Internal fixation was performed using a short femoral nail. Postoperatively, the patient could walk with full weight bearing using a prosthesis on his affected limb. The method of inverting the traction boot to accommodate the flexed knee and stump can be used safely and effectively to achieve and maintain fracture reduction during fixation of intertrochanteric fractures for patients with a below-knee amputated limb.


International Orthopaedics | 2016

Safety in early experience with a direct anterior approach using fluoroscopic guidance with manual leg control for primary total hip arthroplasty: a consecutive one hundred and twenty case series.

Yasuhiro Homma; Tomonori Baba; Hideo Kobayashi; Asuka Desroches; Yu Ozaki; Hironori Ochi; Mikio Matsumoto; Takahito Yuasa; Kazuo Kaneko


European Journal of Orthopaedic Surgery and Traumatology | 2016

Benefit and risk in short term after total hip arthroplasty by direct anterior approach combined with dual mobility cup

Yasuhiro Homma; Tomonori Baba; Hideo Kobayashi; Asuka Desroches; Hironori Ochi; Yu Ozaki; Mikio Matsumoto; Takahito Yuasa; Kazuo Kaneko

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