Biomedical subjects

Yu-Han Chang

Publications and source records attributed to Yu-Han Chang.

8 recordsLinked to original sources

PubMed2006

Staged arthroplasty as salvage procedure for deep hip infection following intertrochanteric fracture.

Deep hip infection is a rare complication of intertrochanteric fractures and an optimal treatment has not yet been reported. Twenty-seven patients who contracted deep hip sepsis following the failed primary treatment of an intertrochanteric fracture were treated with two-stage hip arthroplasty. Antibiotic-impregnated cement beads were implanted following resection arthroplasty in the first 15 patients, and a temporary cement spacer prosthesis was used in the other 12 hips. There was only one recurrence of infection at an average follow-up of 4.8 years. Complications included non-union of the greater trochanter in four patients, intraoperative femoral fracture in two and fracture of the cement prosthesis in one. The use of an interim spacer was associated with better hip function in the interim period; a decreased operative time and less blood loss at the time of arthroplasty; and a higher hip score at final follow-up. Staged arthroplasty is an effective salvage procedure for deep hip infection after the failed treatment of an intertrochanteric fracture. The use of a temporary spacer maintains hip function between stages, makes arthroplasty less complicated, and improves the clinical outcome.

Adult↗

PubMed2006

High concentration and bioactivity of vancomycin and aztreonam eluted from Simplex cement spacers in two-stage revision of infected hip implants: a study of 46 patients at an average follow-up of 107 days.

This study investigated the release of antibiotics in vivo, from an articulating polymethylmethacrylate (PMMA) spacer used in two-stage revision arthroplasty of infected hip implants. Forty-six patients who underwent two-stage revision hip arthroplasty for infections were managed with an interim PMMA spacer loaded with a high dose of vancomycin and aztreonam. Serum and aliquots of drainage collected after the first-stage surgery, and joint fluid obtained at the time of the second-stage surgery were analyzed for antibiotic concentrations by high performance liquid chromatography and bioactivity by tube dilution bioassay. Following implantation, the highest levels of antibiotics were measured in aliquots of drainage on the first day (vancomycin: 1538.0 +/- 243.6 microg/mL; aztreonam: 1003.5 +/- 323.5 microg/mL), decreasing to 571.9 +/- 169.4 microg/mL for vancomycin and 313.6 +/- 88.3 microg/mL for aztreonam after 7 days. Antibiotic concentrations in serum were very low (vancomycin: 0.58 +/- 0.2 microg/mL, range: 0.1-1.6 microg/mL; aztreonam: 0.46 +/- 0.3 microg/mL, range: 0.1-0.9 microg/mL at 24 h) and there was no systemic adverse effect. At a mean 107 days after the first-stage surgery, the concentrations of antibiotics in joint fluid were well above the minimal inhibitory concentration of most common microorganisms. The released antibiotics were bioactive against the test organisms. Based on the observed results, we confirmed the safety and effectiveness of in vivo drug delivery from antibiotic-impregnated PMMA hip spacers.

Aged↗

PubMed2006

Precooling of the femoral canal enhances shear strength at the cement-prosthesis interface and reduces the polymerization temperature.

Preheating of the femoral stem in total hip arthroplasty improves the cement-prosthesis bond by decreasing the interfacial porosity. The main concern, however, is the potential thermal osteonecrosis because of an increased polymerization temperature. In this study, the effects of femoral canal precooling on the characteristics of the cement-stem interface were evaluated in an experimental model for three test conditions: precooling of the femoral canal, preheating of the stem (44 degrees C), and a control in which stems were inserted at room temperature without thermal manipulation of the implant, cement, or bone. Compared to the control group, precooling of the femoral canal and preheating of the stem had similar effects on the cement-stem interface, with greater interfacial shear strength and a reduced porosity. Femoral canal precooling also produced a lower temperature at the cement-bone interface. No difference was found in the ultimate compressive strength of bone cement for the three preparation conditions. Based on this laboratory model, precooling of the femoral canal could improve shear strength and porosity at the stem-cement interface, minimize thermal injury, and maintain the mechanical strength of the cement.

Arthroplasty, Replacement, Hip↗

PubMed2006

Image-guided periacetabular osteotomy: computer-assisted navigation compared with the conventional technique: a randomized study of 36 patients followed for 2 years.

BACKGROUND: Periacetabular osteotomy (PAO) is an effective but technically demanding surgical procedure. We evaluated the efficiency of computer-assisted navigation in PAO and compared it with the traditional approach. PATIENTS AND METHODS: We performed a randomized study of 36 patients undergoing PAO using either the CT-based, computer-assisted navigation technique or the conventional approach. The operative details, radiographic results, and functional outcomes were compared between groups. RESULTS: Patients in the conventional surgery group required an average of 4.4 (2-7) images of intraoperative radiographs, whereas only 0.6 (0-1) images were required in the navigation group. The operation time was 21 min shorter with computer-assisted navigation. No significant difference with regard to operative blood loss, transfusion requirement, correction of deformity, and functional improvement was found. Complications such as intraarticular damage, osteonecrosis, or neurovascular injury were not encountered. INTERPRETATION: A computer-assisted navigation system is a feasible tool to provide real-time image guidance and facilitate PAO. However, it offers little additional benefit when the surgery is done by an experienced surgeon.

Acetabulum↗

PubMed2005

Periprosthetic fractures of the greater trochanter through osteolytic cysts with uncemented MicroStructured Omnifit prosthesis: retrospective analyses pf 23 fractures in 887 hips after 5-14 years.

BACKGROUND: Periprosthetic fractures of the greater trochanter through osteolytic cysts are rare. The proper treatment and its influence on the prosthetic survival remains unknown. PATIENTS AND METHODS: We retrospectively evaluated 887 hips with uncemented MicroStructured Omnifit total hip prostheses at a mean follow-up time of 11 (5-14) years. We found 23 (2.6%) fractures of the greater trochanter through a cystic lesion, occurring 4-11 years postoperatively. RESULTS: Nonoperative treatment healed 15 of the 17 fractures that were minimally displaced. At a mean follow-up of 3 (2-5) years after the fracture, 16 had had revision of the components because of excessive wear, loosening, or nonunion. INTERPRETATION: We conclude that a periprosthetic fracture of the greater trochanter through an osteolytic lesion is usually stable and heals without treatment. However, it is associated with poor prosthetic survival because of excessive polyethylene wear.

Adolescent↗

PubMed2004

Two-stage revision hip arthroplasty for infection: comparison between the interim use of antibiotic-loaded cement beads and a spacer prosthesis.

BACKGROUND: A two-stage revision is a well-accepted method for the treatment of a deep infection of a hip with a joint implant. In the present study, the results associated with the interim use of antibiotic-loaded cement beads were compared with those associated with the interim use of an antibiotic-loaded cement prosthesis. METHODS: One hundred and twenty-eight consecutive patients who were managed with a two-stage revision hip arthroplasty for the treatment of an infection were followed clinically and radiographically for an average of 4.9 years. Cement beads were implanted following resection arthroplasty in the first seventy hips, and a custom cement prosthesis was implanted in the subsequent fifty-eight hips. RESULTS: There was no evidence of recurrent infection in 122 patients (95.3%); the infection-free rates in both groups were similar. The use of a spacer prosthesis was associated with a higher hip score, a shorter hospital stay, and better walking capacity in the interim period; a decreased operative time, less blood loss, and a lower transfusion requirement at the time of reimplantation; and fewer postoperative dislocations. CONCLUSIONS: The present study supports the safety and efficacy of the routine use of an antibiotic-loaded cement prosthesis in the interim between the stages of a two-stage revision procedure for the treatment of an infection at the site of a hip arthroplasty.

Adult↗

PubMed2003

Synovial chondromatosis of the hip: management with arthroscope-assisted synovectomy and removal of loose bodies: report of two cases.

Primary synovial chondromatosis is an uncommon disorder, and involvement of the hip joint is rare. The clinical symptoms are usually non-specific, and a clinical diagnosis of synovial chondromatosis of the hip may be difficult and delayed, especially before the ossifying nodules become evident. Loose bodies in the joint can cause secondary degenerative osteoarthritis of the hip. Currently, the recommended management is surgical removal of the loose bodies and a synovectomy without dislocation of the hip joint. Herein we report on 2 cases of synovial chondromatosis of the hip, which were managed with an arthroscope-assisted synovectomy and removal of the loose bodies. We believe this is an easy and safe method for management of this disorder.

Adult↗

PubMed2002

Conditions before collapse of the contralateral hip in osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head is a disease which may cause rapid femoral head collapse in relatively young patients. Clinical results of prosthesis replacement in osteonecrosis patients are generally poorer than in age-matched patients with other diagnoses. The ultimate goal in treating these patients is therefore to preserve not replace the involved femoral head. The purposes of this study were to analyze outcomes by examining osteonecrotic hips before collapse and to justify the role of early surgical intervention for osteonecrosis of the femoral head. METHODS: Between 1993 and 1997, there were 275 consecutive patients with osteonecrosis of the femoral head who received joint replacement on 1 side. Among these patients, 100 contralateral hips with evidence of osteonecrosis in the stage before collapse were included in this study. Demographic information, laboratory data, and radiographs were reviewed and compared between patients whose collapse time was less than 1 year, between 1 and 2 years, and more than 2 years, and those who had no collapse at the latest follow-up. RESULTS: At the final follow-up, the overall collapse rate was 78%, and the collapse time was generally within 2 years. Patients with younger age (less than 50 years old), higher activity levels, and higher serum triglyceride levels were at higher risk of rapid collapse. CONCLUSION: In conclusion, we found that the disease progression rate is high in patients who have bilateral femoral head involvement. Early surgical intervention to preserve the femoral head should be adopted to prevent early femoral head collapse in these patients. In addition, risk factors such as high activity levels and abnormal lipid metabolism should also possibly be addressed in the therapeutic modality.

Adult↗