Chang Hyun Nam

The Short-term Follow-up Results of Open Wedge High Tibial Osteotomy with Using an Aescula Open Wedge Plate and an Allogenic Bone Graft: The Minimum 1-Year Follow-up Results

Background This study examined the results of open wedge high tibial osteotomy with using an Aescula open wedge plate and an allogenic bone graft as a surgical technique for the patients who suffer from osteoarthritis of the knee with a genu varum deformity. Methods From March 2007 to August 2007, 33 patients (37 cases) with osteoarthritis of the knee and a genu varum deformity underwent a high tibial osteotomy with using an Aescula open wedge plate and an allogenic bone graft. The patients were followed up for more than 1 year. Before and after surgery, the correction angle of the genu varum was measured by the lower extremity scannogram and the posterior tibial slope, the joint space distance and the time to bone union were evaluated. The functional factors were evaluated using the Knee Society Score. Results The average knee score and function score improved from 52.19 ± 11.82 to 92.49 ± 5.10 and 52.84 ± 6.23 to 89.05 ± 5.53, respectively (p < 0.001). According to the lower extremity scannogram, the mean preoperative varus angle was -1.86 ± 2.76°, and the average correction angle at the last follow-up was 10.93 ± 2.50° (p < 0.001). The tibial posterior slope before surgery and at the last follow-up were 8.20 ± 1.80° and 8.04 ± 1.30°, respectively (p = 0.437). The joint space distance increased from 4.05 ± 1.30 mm to 4.83 ± 1.33 mm (p < 0.001). The average time to complete bone union was 12.69 ± 1.5 weeks. Conclusions An open wedge high tibial osteotomy using an Aescula open wedge plate and an allogeneic bone graft to treat osteoarthritis of the knee with a genu varum deformity showed good results for the precision of the correction angle, the time to bone union and the functional improvement.

Cerebral fat embolism syndrome after simultaneous bilateral total knee arthroplasty: a case series.

Total knee arthroplasty (TKA), particularly when performed as a simultaneous bilateral procedure, theoretically increases the risk for entry of fat globules into the blood stream. The frequency of cerebral fat embolism syndrome (CFES) was retrospectively investigated among 2345 simultaneous bilateral TKA procedures performed from August 2006 to May 2010. During that period, 9 patients presented with neurologic deficits after surgery and underwent brain magnetic resonance imaging. For identification of CFES among them, we used both magnetic resonance imaging findings and clinical criteria modified from the original one of Gurd and Wilson (J Bone Joint Surg Br 1974; 56B:408). Four patients fulfilled the modified criteria. The overall incidence of CFES occurring after simultaneous bilateral TKA was 0.17%. Cerebral fat embolism syndrome should be ruled out, although rare, in patients who present with neurologic impairment after TKA.

Delayed Femoral Fracture Through a Tracker Pin Site After Navigated Total Knee Arthroplasty

Femoral shaft fractures through a tracker pin site after computer navigated total knee arthroplasty are being increasingly reported. All previously reported fractures have occurred within 3 months of surgery, and thus, any patient with an unexpected thigh pain during the early postoperative period should be carefully monitored for a potential fracture and receive appropriate follow-up care. However, unlike these fractures, we encountered a navigation pin-associated delayed femoral shaft fracture during the late postoperative period (at 12 months postoperatively), which we believe, might be associated with transcortical drilling marks.

Acetabular screw head-induced ceramic acetabular liner fracture in cementless ceramic-on-ceramic total hip arthroplasty.

Ceramic liner fractures are rare after ceramic-on-ceramic THA. This article describes a case of an early ceramic liner fracture caused by impingement with a tilted acetabular screw head 2 months after cementless ceramic-on-ceramic THA. A 59-year-old man underwent primary THA for avascular necrosis of his right femoral head. The implant used was an Osteonics Secur-Fit HA ceramic-on-ceramic bearing system. The metal shell was fixed with 1 cancellous bone screw. During the index procedure, the acetabular screw seemed tilted in the metal shell hole, but the liner was fully seated in the metal shell without difficulty. However, 2 months later he re-presented due to pain and crepitation in the right hip. Radiographs showed that the ceramic acetabular insert had fractured. At revision, ceramic insert had fractured into large and numerous comminuted fragments, and the acetabular screw head was slightly tilted and protruded over the inner surface of the metal shell, which had worn eccentrically. The ceramic inner head and metal shell were visibly intact. Because the metal shell-bone fixation was firm, a new identical design ceramic liner and head were fitted, and no adverse event has occurred since. This case suggests that a complete check of the inside of the shell should be made when using an acetabular screw and ceramic liner. In particular, the screw head must not be tilted or left proud of the inside surface of the shell. Correct acetabular screw direction and seating are essential to avoid detrimental clinical consequences.

Anterior Dislocation After a Posterior Stabilized Total Knee Arthroplasty

Dislocation of a total knee arthroplasty is a rare but serious complication. In previous literature, when dislocation does occur, it is usually in the posterior direction in cases with a posterior stabilized total knee arthroplasty due to cam jump. We report an unusual case of anterior dislocation of an 11-year-old posterior stabilized total knee arthroplasty in a 55-year-old woman with rheumatoid arthritis occurred after a slip.

Analysis of Synovial Fluid in Culture-negative Samples of Suspicious Periprosthetic Infections

Synovial fluid analysis can help to rule out a periprosthetic infection. The goal of this study was to evaluate the prognostic significance of synovial fluid suspicious for a periprosthetic infection given the synovial leukocyte count and percent of neutrophils. From August 2006 to November 2008, patients who had synovial fluid aspirated for painful knees and elevated C-reactive protein levels after total knee arthroplasty but revealed no growth of any microorganism were retrospectively evaluated by medical record review. Mean follow-up period was 827.7±250.6 days from the date of joint aspiration results. The optimal cut-off values for synovial leukocyte counts and percent neutrophils were determined using receiver operating characteristic curves. From a total of 56 patients, 14 were classified as having poor results. The remaining 42 patients had an uneventful clinical course with a stable prosthesis on radiographs without specific therapy during the follow-up period. The receiver operating characteristic curve showed that a synovial leukocyte count of 3600/uL had an 86% sensitivity and 79% specificity; with 89% synovial neutrophils, the sensitivity was 72% and specificity 62%. The synovial fluid leukocyte count and percent neutrophils were significant predictors of outcome in patients with cultures that were negative but suspicious for periprosthetic infections.

Radiographic Healing With Hemispherical Allogeneic Femoral Head Bone Grafting for Opening-Wedge High Tibial Osteotomy

PURPOSE The aim of this study was to investigate the remodeling process after hemispherical femoral head allograft grafting in opening-wedge high tibial osteotomy with a plate and screw. METHODS The study group included 105 knees in 92 women and 7 knees in 7 men from January 2007 through December 2007. The radiographic bone remodeling process was determined by use of a modification of the radiologic rating system described previously by van Hemert et al. in 4 groups: group A, 7-mm plate correction; group B, 9-mm plate correction; group C, 11-mm plate correction; and group D, 13-mm plate correction. RESULTS The postoperative femorotibial angle and tibial slope were not significantly changed at latest follow-up in comparison to immediate postoperative status. The mean follow-up period was 25.4 months (range, 18 to 30 months). In all groups radiologic bone healing higher than phase 3 was successfully achieved between 3 and 6 months. The healing process slowed with increasing correction angle. CONCLUSIONS A hemispherical femoral head allograft is a good alternative osseous graft material when patients are selected appropriately with the following criteria: body mass index lower than 40, no symptomatic osteoarthritis of the patellofemoral joint and lateral compartment, no systemic inflammatory arthritis, no history of fracture or previous open surgery to the lower limb, and no flexion contracture. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Transepicondylar axes for femoral component rotation might produce flexion asymmetry during total knee arthroplasty in knees with proximal tibia vara

BACKGROUND Adequate rotation of the femoral component in total knee arthroplasty is mandatory for prevention of numerous adverse sequelae. Therefore, we investigate whether there is the distal femoral deformity in knees with tibia vara. The purpose of this study was to evaluate the reliability of the transepicondylar axis as a rotational landmark in knees with tibia vara. METHODS We retrospectively reviewed and selected 101 osteoarthritic knees with proximal tibia vara and 150 osteoarthritic knees without tibia vara for inclusion in this study. The transepicondylar axis (TEA), anteroposterior (AP) axis and posterior condylar (PC) line were measured using the axial image from magnetic resonance imaging axial images. We compared the external rotation angle of the TEA relative to the PC line between groups in order to investigate the presence of distal femoral anatomical adaptation in the tibia vara group. RESULTS The TEA in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 6.0º of external rotation in the non-tibia vara group. The line perpendicular to the AP axis in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 5.4º of external rotation in the non-tibia vara group. Distal femoral geometry was unaffected by the tibia vara deformity. CONCLUSIONS The use of transepicondylar axes in determining femoral rotation may produce flexion asymmetry in knees with tibia vara. LEVEL OF EVIDENCE Level III.

Disassembly of threaded junction between stem extension and femoral component in a total stabilizer revision total knee arthroplasty

We report an unusual case of disassembly of threaded junction between stem extension and femoral component in a 6-year-old total stabilizer revision total knee arthroplasty. Aseptic loosening of femur component will tend to cause increased stresses at the stem-condylar junction of a modular femoral prosthesis, especially if femur component is flexed. The modular junction may therefore be unable to withstand the concentrated force and lead to disassembly.

Mucoid Degeneration of Posterior Cruciate Ligament Leads to Roof Impingement with Anterior Cruciate Ligament: Case Report

Mucoid degeneration of cruciate ligament is rare cause of knee pain, however there are some cases causing pain and restriction of extension. A 60-year-old man came to our clinic complaining of pain in knee joint on full range of extension about 3 months ago. The range of motion (ROM) was a flexion contracture of 5 degree and a further flexion of 140 degree with pain aggravation by forced extension. Magnetic resonance imaging of the knee joint showed thickened posterior cruciate ligament (PCL) mucoid degeneration. Arthroscopic treatment consists of PCL reduction-plasty by debridement of yellowish material in the PCL fiber and reduces the volume of the hypertrophied PCL. Immediately after surgery, patient gain the full ROM without any symptom of impingement. Enlarged PCL can make impingement in femoral notch with anterior cruciate ligament (ACL). Then, Partial debulking surgery of PCL is an effective treatment to pain relief and restore ROM of knee.