Further Imaging for Suspected Isolated Greater Trochanteric Fractures: Multiplanar Reformation Computed Tomography or Magnetic Resonance Imaging

Kangbaek Kim,Sun Hyung Lee,Jeong Joon Yoo,Hee Joong Kim 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.1

Background: Most isolated greater trochanter (IGT) fractures are treated conservatively. However, some require surgical fixation although indications for surgery have not yet been established. Many surgeons perform surgical fixation when the intertrochanteric extension crosses the midline on magnetic resonance (MR) images. Nevertheless, for mechanical strength, cortical bone integrity is more important than that of intramedullary cancellous trabeculae. We retrospectively evaluated the clinical usefulness of multiplanar reformation computed tomography (MPR CT) in determining treatment strategies for IGT fractures. Methods: We evaluated 99 cases of suspected IGT fractures between October 2004 and December 2019. They were 66 women and 33 men with a mean age of 77 years. The mean follow-up period was 34 months. Most patients were evaluated with plain radiographs, followed by additional imaging study via MPR CT in 65 cases, magnetic resonance imaging (MRI) in 5 cases, and both in 17 cases. Typically, fractures were fixed surgically when a cortical breakage was detected in the intertrochanteric area on MPR CT, while fractures without evidence of cortical breakage on MPR CT were treated conservatively. Results: In 13 out of 82 cases evaluated by MPR CT, incomplete cortical breakage in the intertrochanteric area was detected, of which 10 were treated surgically. The remaining 3 cases were treated conservatively due to patient’s refusal, poor medical condition, and failure to detect breakage. Of 69 cases without cortical breakage, 61 cases were successfully treated conservatively. Among the 17 cases evaluated by both MPR CT and MRI, cortical breakage was detected in 3, of which the intertrochanteric extension crossed the midline on the MR image only in 1 case. Of the remaining 14 cases without breakage, the intertrochanteric extension crossed the midline in 5. Among these 5 cases, 3 were treated conservatively. Conclusions: The results suggest that MPR CT is a useful imaging modality for further evaluation of IGT fractures. It was especially valuable in evaluating cortical bone integrity, which may be more critical for fracture stability.

Gross Trunnion Failure in the Bipolar Hemiarthroplasty; Raising Concern about Short Trunnion: A Case Report

( Kangbaek Kim ),( Junpyo Lee ),( Jeong Joon Yoo ),( Hee Joong Kim ) 대한고관절학회 2021 Hip and Pelvis Vol.33 No.1

There have been some reports of gross trunnion failure (GTF) in total hip arthroplasty. Here, we report a case of GTF 19 years after bipolar hemiarthroplasty using a 28-mm head with a 14/16 taper bore. Compared to other GTF reports, the current case had some unusual aspects: bipolar hemiarthroplasty, 28-mm head, relatively lateonset, and no apparent findings of metallosis though a severe one was evident. A Computed tomography scout view provided valuable information in evaluating polyethylene, metal head, and neck inside the bipolar cup. The current report suggests a need for concerned regarding short trunnion length which may be associated with GTF.

Incomplete Intertrochanteric Fracture: A Pattern Analysis Using Multiplanar Reformation Computed Tomography

Hee Joong Kim,Jae Youn Yoon,Sunhyung Lee,Kangbaek Kim,Jeong Joon Yoo 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.3

Background: Incomplete fractures are assumed to occur in the intertrochanteric area as fractures at other sites, but reports of incomplete intertrochanteric fractures (IIFs) are rare. In 1999, Schultz et al. defined isolated greater trochanter fractures (GTFs) as IIFs when intertrochanteric extension is observed on magnetic resonance (MR) images. On multiplanar reformation computed tomography (MPR CT) images acquired for further study of apparently isolated GTFs, we noted incomplete cortical breakage in the intertrochanteric area. We then found that the fracture line was incomplete on plain radiographs in some intertrochanteric fractures. We evaluated IIFs and apparently isolated GTFs using MPR CT and analyzed the fracture patterns of IIFs that were confirmed using MPR CT. Methods: Between February 2006 and June 2019, 36 cases of IIF were detected using MPR CT in 36 patients. They were 17 women and 19 men with a mean age of 74.7 years (range, 26–94 years). Plain radiographs and MPR CT images were evaluated by two experienced orthopedic surgeons. In addition, MR imaging was performed in 5 cases. Results: Plain radiographs showed no evidence of fracture in 2 cases, isolated GTF in 7 cases, and IIF in 27 cases. In all cases, incomplete cortical breakage in the intertrochanteric area was confirmed on MPR CT images. Cortical breakage was located in the anterior portion of the intertrochanteric area, whereas the posterior portion remained intact in all cases. The detection rate of cortical breakage was higher on coronal or sagittal images than that on axial images. On MR images of 5 cases, intertrochanteric extensions were found in the medullary space. All extensions originated in the greater trochanter area and extended anteriorly in the axial plane and inferomedially in the coronal plane. On the T1-weighted mid-coronal image, the extension reached or passed the midline in 3 cases, and cortical breakage was detected in only 2 cases. Conclusions: In all cases of IIF, cortical breakage was detected in the anterior portion of the proximal femur, leaving the posterior cortex intact. This finding is notably different from that of intertrochanteric extension (from posterior to anterior) detected on MR images of isolated GTFs

Total Hip Arthroplasty Performed with a Novel Design Type 1 Femoral Stem: A Retrospective Minimum 5-Year Follow-up Study

Hanbual Yang,Kangbaek Kim,Hong Seok Kim,Jeong Joon Yoo 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.1

Background: The Bencox M stem is a mid-short type 1 stem with additional unique design features. It has a reduced stem length and a lateral shoulder to facilitate minimally invasive surgery, as well as an angular lateral shoulder and a trapezoidal neck to minimize stem-liner impingement. There have been many mid-term reports on type 1 stems, but no results have been reported so far on this novel design type 1 femoral stem. This study presents the clinical and radiological outcomes of total hip arthroplasty performed with the M stem after a minimum 5-year follow-up. Methods: From July 2014 to February 2015, 125 primary total hip arthroplasties using the M cementless femoral stem were performed on 112 patients in our hospital. Among them, 94 patients (106 hips) were eligible for the study and were followed up for more than 5 years. Our primary outcome was clinical results, which were evaluated by the Harris Hip Score (HHS), thigh pain, noise, and other complications. Secondary outcome was radiological outcomes. Seventy-seven hips were evaluated radiologically with attention to implant fixation, migration, loosening of component, degree of stress shielding, radiolucent lines, focal osteolysis, heterotopic ossification, and the evidence of impingement between the stem and liner. Results: The average HHS improved from 54.6 points (range, 24–67 points) to 96.8 points (range, 91–100 points) at the latest follow-up. Three hips (2.8%) had intermittent thigh pain, which was tolerable without medication. Five hips (4.7%) had ceramicrelated noise. There were no other complications such as infection, nerve injury, dislocation, or revision. All implants showed radiographic evidence of stable fixation by bone ingrowth without migration. Fifty-seven hips (74%) showed mild femoral stress shielding. Distal cortical hypertrophy was detected in 7 hips (9%), and heterotopic ossification was observed in 17 hips (22%). No implant demonstrated focal osteolysis and notching of the femoral neck or shoulder on radiographs. Conclusions: The minimum 5-year results of total hip arthroplasty performed with the M cementless femoral stem were encouraging clinically and radiologically. A long-term follow-up will be necessary to evaluate its longevity.

반사형 마이크로 디스플레이 액정 내 이온의 움직임과 DC 오프셋 전압에 미치는 영향

황성희,김강백,신동수 한양대학교 이학기술연구소 2006 이학기술논문지 Vol.9 No.-

반사형 마이크로 디스플레이인 liquid crystal on Si (LCoS) cell 내에는 전극으로 쓰이는 Al 과 ITO 사이의 일함수 차이에 의해 built-in voltage가 존재한다. built-in voltage는 flicker, image sticking 현상 등을 야기시키므로, 이를 상쇄키기 위하여 DC offset voltage를 가해주어야 한다. liquid crystal (LC) 내부의 이온이 전기장에 따라 운동하며, 시간이 지남에 따라 이온의 농도도 변화하기 때문에 DC offset voltage는 시간에 따라 변화시켜야 한다. 이번 논문에서는 이온의 움직임과 charge screening 효과에 따른 DC offset voltage의 변화를 시간의 함수로 측정하였다. The built-in voltage exists in the reflective liquid crystal on Si (LCoS) cell due to the work-function difference between the Al and ITO layers. Since the built-in voltage can cause flicker and image sticking phenomena, DC offset voltage should be applied to cancel it. As ions in the liquid crystal (LC) cell migrate under the electric field and the ion concentration itself varies with time, the DC offset voltage needs to be changed over time. In this paper, we present the change of the DC offset voltage as a function of time, which is caused by the ion motion and the charge screening effect.

Comprehensive Guidance for the Prevention of Periprosthetic Joint Infection After Total Joint Arthroplasty and Pitfalls in the Prevention

Parvizi Javad,Cha Yonghan,Chisari Emanuele,Kim Kangbaek,Koo Kyung-Hoi 대한의학회 2024 Journal of Korean medical science Vol.39 No.15

Total joint arthroplasty (TJA) is a surgical procedure, in which parts of damaged joints are removed and replaced with a prosthesis. The main indication of TJA is osteoarthritis, and the volume of TJA is rising annually along with the increase of aged population. Hip and knee are the most common joints, in which TJAs are performed. The TJA prosthesis is composed of metal, plastic, or ceramic device. Even though TJA is the most successful treatment for end-stage osteoarthritis, it is associated with various complications, and periprosthetic joint infection (PJI) is the most serious complication after TJA. With the increasing volume of TJAs, there is a simultaneous rise in the incidence of PJI. Contamination of the surgical wound and the adherence of bacteria to the surface of prosthetic component represent the initial step in the pathogenesis of PJI. The main sources of the contamination are 1) patient's own flora, 2) droplets in the operation room air, and 3) surgical gloves and instruments. Even though modern techniques have markedly reduced the degree of contamination, TJAs cannot be done in completely germ-free conditions and some degree of contamination is inevitable in all surgical procedures. However, not all contamination leads to PJI. It develops when the burden of contamination exceeds the immune threshold or the colony forming units (CFUs) and various factors contribute to a decrease in the CFU level. Surgeons should be aware of the germ burden/CFU concept and should monitor sources of contamination to maintain the germ burden below the CFU to prevent PJI.