Biomedical subjects

Pang-Hsin Hsieh

Publications and source records attributed to Pang-Hsin Hsieh.

18 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

One-stage posterior cruciate ligament inlay reconstruction combining anterior cruciate ligament reconstruction following knee dislocation.

Knee dislocation is a rare but severe injury that involves damage to the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), lateral or medial ligamentous structures, and other soft tissues or bony structures surrounding the knee joint. No consensus exists regarding the best treatment method. This work presents a method of 1-stage ACL and PCL reconstruction in which a contralateral quadriceps tendon-bone autograft with tibial inlay technique is used for the PCL and contralateral hamstring tendon autograft with suspension fixation is used for the ACL. After harvesting grafts, the patient is put in the lateral decubitus position. Under arthroscopy, the femoral tunnel for the anterolateral bundle of the PCL is created using an 8-mm reamer via a prepositioned guide pin. Next, the tibial tunnel of the ACL is created with an appropriate diameter cannulated reamer. Directed by the femoral guide instrument with a 7-mm offset, a guide pin is positioned retrograde through the tibial tunnel. A reamer is then used to create a 35-mm long closed-ended femoral tunnel for the ACL. A posterior arthrotomy for the PCL inlay technique is performed. After capsulotomy, a unicortical window is created at the footprint of the PCL and the inlay graft is fixed using a 3.5mm-cancellous screw and washer. The PCL graft is then passed into the femoral tunnel. The ACL graft is passed in a retrograde fashion using the Beath pin. The ACL graft is fixed by tying with a washer on the femoral side and by tying with a screw on the tibial side. The PCL graft is then fixed on the femoral side.

Anterior Cruciate Ligament↗

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↗

PubMed2006

Closed reduction and internal fixation for acute midshaft clavicular fractures using cannulated screws.

BACKGROUND: Although most acute midshaft clavicular fractures can be successfully treated nonsurgically, surgery is more appropriate for cases with severe displaced fractures, skin tenting, initial shortening of fracture ends, and associated with multiple injuries. However, methods of surgical treatment for such fractures remain controversial. This study discusses a closed reduction and internal fixation technique for midshaft clavicular fracture. METHODS: Between 2000 through 2003, 34 acute midshaft clavicular fractures were operatively treated with cannulated screws using closed reduction technique by one surgeon. The follow-up and clinical evaluation was performed by another surgeon. RESULTS: Thirty-one patients were followed for an average of 27.4 months (range, 24-37 months). Thirty (96.8%) fractures healed within 12 weeks, and one fracture healed at 18 weeks. No major surgical complications occurred, although superficial wound infection occurred in one patient. No implants needed to be removed. The final union rate was 100%. CONCLUSIONS: Closed reduction and internal fixation with cannulated screw is an alternative choice for treating acute midshaft clavicular fracture in selected cases where surgery is indicated and should be done cautiously.

Adolescent↗

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↗

PubMed2005

Biomechanical comparison of newly designed stemless prosthesis and conventional hip prosthesis--an experimental study.

Local bone loss after implantation of traditional stem-type prostheses remains an unsolved problem during the long-term application of total hip replacement. The stress shielding effect and osteolysis were thought to be the two main factors that result in local bone loss after prosthesis implantation. A newly designed stemless cervico-trochanteric (C-T) prosthesis was thus developed to reduce stress shielding and osteolysis caused by the implantation of conventional stem-type prosthesis. Eight synthetic femora were implanted with C-T and porous coated anatomic (PCA) prostheses. Under 2,000-Newton load, the surface strains of proximal femora were compared between the intact, PCA press-fit femora and the C-T implanted femora with three different fixation modes: two-screw fixation, three-screw fixation, and three-screw combined with cement fixation. The results revealed that stress shielding in the C-T implanted femora was significantly eliminated compared to that of the PCA implanted femora (p<0.01). No statistical difference in strain magnitude was found for the C-T implanted femora among the three different fixation modes (p>0.1). The C-T implanted femur has more physiological strain distribution. Moreover, from the C-T prosthetic characteristic design, the localized osteolysis would be also reduced due to the overall coverage of neck-trochanteric area. The newly designed C-T prosthesis may be a useful alternative to the traditional stem-type prosthesis in the future.

Arthroplasty↗

PubMed2004

Selection of fixation devices in proximal femur rotational osteotomy: clinical complications and finite element analysis.

OBJECTIVE: To compare the postoperative stability between large cancellous screws fixation and dynamic hip screws fixation in transtrochanteric rotational osteotomy. DESIGN: Finite element analysis was designed to validate the clinical outcomes of fixation failure in transtrochanteric rotational osteotomy. BACKGROUND: From 1997 to 2000, transtrochanteric rotational osteotomy had been done in 20 osteonecrotic hips. Fixation with large cancellous screws as suggested by Sugioka had been used in the first five hips. Unfortunately, fixation failures were encountered in all of the five cases. The fixation mode was then shifted to a combination of plate and screws, no fixation failure had been observed postoperatively. A finite element analysis was designed to investigate the causes of fixation failure. METHODS: Finite element models for four dynamic hip screw instrumented femora and four large screws instrumented femora simulating four different levels of bone cut were created. The von Mises stress distributions of each model were analyzed and compared for a loading condition simulating single-legged stance. RESULTS: Analysis results confirmed our clinical observation that fixation with screws had higher stress concentration on the proximal femur. Improper bone cut, especially those that are too distal from the intertrochanteric line, had higher risks of fixation failure. CONCLUSIONS: Transtrochanteric rotational osteotomy is a technically demanding procedure such that surgical principles should be abided carefully to avoid catastrophic complications. RELEVANCE: Finite element analysis results demonstrated that dynamic hip screw fixation provides better stability and prevents fixation failure that corresponds with the clinical observation.

Adult↗

PubMed2004

Two-stage revision hip arthroplasty for infection with a custom-made, antibiotic-loaded, cement prosthesis as an interim spacer.

BACKGROUND: Two-stage reconstruction is a well-recognized treatment for deep infection of hip joint implants. The purpose of the study was to report the results of our treatment using a standardized protocol. METHODS: Forty-two consecutive patients with deep infection of the hip prosthesis were treated according to a prospective, two-stage resection/reimplantation protocol. Between stages, a custom-made, antibiotic-loaded, cement prosthesis was implanted as an interim spacer. RESULTS: Infection was eradicated in 41 patients after the first-stage operation. Thirty-six patients remained with the ability to walk with the interim cement pros-thesis. For 40 patients who underwent reimplantation, recurrence of infection was observed in only 1 patient at an average of 55.2 months' follow-up. CONCLUSION: We have found that our two-stage treatment protocol is a reliable approach for the management of infected hip prostheses. It is effective for eradicating infection and for providing a mobile and functional joint through the treatment course.

Adult↗

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

Treatment of early cut-out of a lag screw using a trochanter supporting plate: 11 consecutive patients with unstable intertrochanteric fractures.

INTRODUCTION: Superior cut-out of a lag screw remains a serious complication in the treatment of intertrochanteric fractures. It is related to the stability of fracture reduction. We describe the application of a trochanter supporting plate (TSP) to restore the fracture stability after early cut-out of a lag screw in unstable intertrochanteric fractures. MATERIALS AND METHODS: A total of 11 consecutive patients with superior cut-out of the lag screw of a dynamic hip screw (DHS) or a gamma nail in an unstable intertrochanteric fracture occurring within 6 months after surgery were included in the present study. They underwent repeat surgery for placement of a DHS and a laterally mounted TSP of our design. All patients were monitored for at least 6 months (median 15 months; range 6-28 months). RESULTS: There was no repeated cut-out of a lag screw, and 10 patients (91%) achieved bony union within 5 months. At the last follow-up, all patients could walk with or without aids. CONCLUSION: It reveals that a TSP, as an adjuvant to a lag screw placed inferiorly, is an easy and safe solution for the treatment of early cut-out of a lag screw in unstable intertrochanteric fractures.

Aged↗

PubMed2003

Finite element analysis of the cervico-trochanteric stemless femoral prosthesis.

OBJECTIVE: To investigate the biomechanical performance of a newly designed cervico-trochanteric stemless prosthesis by comparing the stress distribution with that of the traditional stem-type porous-coated anatomic prosthesis. DESIGN: Three-dimensional finite element models were created for the intact femur, cervico-trochanteric implanted femur and porous-coated anatomic implanted femur. The stress distributions on the femur and the implant were compared. The effects of using two or three screws fixation for the cervico-trochanteric implanted femur were also investigated. BACKGROUND: Local bone loss after implantation of traditional stem-type prostheses remains an unsolved problem during the long-term application of total hip replacement. The stress shielding effect and osteolysis were thought to be the two main factors that result in local bone loss after prosthesis implantation. In order to eliminate the mechanical and the biological causes of bone loss after total hip arthroplasty, a newly designed stemless femoral prosthesis was investigated. METHODS: Three-dimensional finite element models were created for the intact, cervico-trochanteric (with two or three fixation screws), and porous-coated anatomic implanted femora with the geometry of a standardized composite femur. Analysis was performed for a loading condition simulating the single-legged stance. The von Mises stress distributions of each model were analyzed and compared. RESULTS: The results can be summarized as follows: (1) Von Mises stress in the proximal, medial femur for the cervico-trochanteric implanted model was higher than that of the intact model and the porous-coated anatomic implanted model; (2) stress-shielding effect of the cervico-trochanteric models (with two or three fixation screws) were eliminated as compared with the porous-coated anatomic model; (3) no obvious difference in von Mises stress distribution for the cervico-trochanteric implanted model with two or three fixation screws. CONCLUSIONS: The cervico-trochanteric femoral prosthesis may reduce the stress-shielding effect of the proximal femur and achieve a more physiological stress distribution on the proximal femur than that of the porous-coated anatomic prosthesis. RELEVANCE: The new concept of cervico-trochanteric stemless prosthesis has proven to possess several advantages based on the current results, and may be an alternative for traditional stem-type prostheses in future clinical applications.

Biomechanical Phenomena↗

PubMed2003

A modified periacetabular osteotomy with use of the transtrochanteric exposure.

BACKGROUND: Periacetabular osteotomies are technically demanding surgical procedures. We developed a modified technique that uses a transtrochanteric approach. Our goal was to facilitate surgical exposure without compromising the results of surgery. The purpose of the present study was to review the early results in our initial group of patients who had this procedure. METHODS: We retrospectively reviewed the results of a modified periacetabular osteotomy in thirty-eight consecutive patients (forty-six hips) at an average duration of follow-up of 4.2 years. The average age of the patients was thirty-one years (range, eighteen to fifty-eight years) at the time of surgery. We evaluated the results with use of serial radiographs and the Merle d'Aubigné and Postel hip-scoring system. RESULTS: All osteotomies healed. Preoperatively, the average lateral center-edge angle was 3 degrees (range, -15 degrees to 12 degrees ), the anterior center-edge angle was 0 degrees (range, -20 degrees to 5 degrees ), the acetabular angle of Sharp was 57 degrees (range, 50 degrees to 68 degrees ), and the femoral head coverage was 53% (range, 40% to 66%). Postoperatively, the average lateral center-edge angle was 35 degrees (range, 23 degrees to 45 degrees ), the anterior center-edge angle was 32 degrees (range, 20 degrees to 55 degrees ), the acetabular angle of Sharp was 40 degrees (range, 37 degrees to 45 degrees ), and the femoral head coverage was 92% (range, 85% to 100%). The average amount of medialization of the femoral head was 6 mm. At the latest follow-up examination, improvement in the grade of osteoarthritis was noted in eight hips, while progression of osteoarthritis was seen in five hips. Functionally, the average Merle d'Aubigné and Postel hip score improved from 13.2 points preoperatively to 17.0 points postoperatively. No patient had a neurovascular complication. CONCLUSION: Our early experience with a modified periacetabular osteotomy showed encouraging results in terms of the technical ease of the technique and the outcome in our patients.

Adolescent↗

PubMed2003

Mini-open intramedullary nailing of acute femoral shaft fracture: reduction through a small incision without a fracture table.

BACKGROUND: Femoral shaft fractures are usually treated with intramedullary nailing. In this study, we report on a modified surgical technique with reduction through a small incision for this type of fracture. METHODS: From 1994 to 1997, this technique was used on 74 patients with 82 femoral shaft fractures. Seventy patients (76 fractures) with at least 3 years of postoperative follow-up were included for clinical evaluation. The surgical technique involves a mini-wound at the fracture site, and fracture reduction is performed with 1 finger or a bone hook without the use of a fracture table. RESULTS: Seventy-four fractures (97%) healed in the first 6 months. In 2 patients, there was little evidence of fracture union at 6 months. One of these 2 patients was treated with an open bone graft, and the other was treated with a closed exchanging nail. Finally these 2 patients healed. The mean operation time for this procedure was 75 minutes. CONCLUSION: The advantages of this procedure include that no fracture table is needed, there is a shorter operation time, there is a small amount of blood loss, and it is especially suitable for multiple trauma patients.

Acute Disease↗

PubMed2002

Primary total hip arthroplasty without the use of bone cement: a 10-year follow-up of 157 hips.

BACKGROUND: The cementless fixation technique in total hip arthroplasty (THA) was developed to solve clinical problems such as aseptic loosening and osteolysis which were thought to be associated with the use of bone cement. This retrospective study reports our mid-term results with cementless THA. METHODS: A series of 173 consecutive, unselected cementless THA procedures using the Omnifit prosthesis was performed by a single surgeon. Sixteen hips were excluded from the study because of insufficient follow-up evaluation. One hundred and fifty-seven THAs with an average follow-up period of 10.2 (range, 5-12) years were retrospectively reviewed. RESULTS: The overall revision rate was 7.0%. Ninety-five percent of unrevised hips achieved a Merle D'Aubigne hip score of 16 points or above. Radiographically, bone ingrowth occurred in all unrevised cups, and in 95% of unrevised stems. Osteolytic lesions, seen on 28.1% of femora and 8.9% of pelvises, appeared at an average of 3.8 years postoperatively. Femoral osteolytic lesions were confined to the proximal Gruen zones 1 and 7. The mean annual polyethylene wear rate was 0.15 mm. Approximately 1/3 of the hips were noted to have excessive wear. CONCLUSION: These results suggest that cementless Omnifit THA provides stable fixation for as long as 12 years after implantation. Of significant concern is the high incidence of excessive polyethylene wear and associated osteolysis. Our experience also indicates that a femoral stem with a circumferential porous coating in the proximal region can protect the femur from distal osteolysis.

Adult↗

PubMed2002

Bridge-plating osteosynthesis of 20 comminuted subtrochanteric fractures with dynamic hip screw.

BACKGROUND: A prospective clinical trial was conducted to evaluate the conjunctive use of an extramedullary device and the bridge-plating technique in the treatment of comminuted subtrochanteric fractures with major extension into the femoral shaft. METHODS: A Winquist criteria was used to classify 3 fracture patterns. The type 3 fractures were excluded from this study because of great extent of the fracture zone for which the bridge-plating technique is not indicated. There were 14 men and 6 women, with a mean age of 49 (range, 17-76) years. A dynamic hip screw (DHS) with a long side plate was chosen as the fixation device because of the small learning curve. RESULTS: The fractures united at a mean of 7.6 (range, 3-15) months postoperatively. Mobility was scored at 9 points in 18 patients and 6 points in 2 patients (Mobility score of Parker & Palmer). Pain was absent in 14, mild in 3, and moderate in 3 patients. Two limbs were shortened by 1 and 1.5 cm, respectively. CONCLUSION: Our results indicate that DHS fixation using the bridge-plating technique leads to union of all comminuted Winquist types 1 and 2 fractures without major complications, and it is a valuable alternative to new intramedullary devices. This procedure offers the significant advantage of being less technically demanding.

Adolescent↗

PubMed2000

Cementless total hip arthroplasty using the omnifit system: An 8.2 year follow-up study of 166 hips.

One hundred and sixty-six cementless primary total hip arthroplasties were performed in 133 patients with porous coated Omnifit prosthesis. The average age was 49.7 years. The mean follow-up period was 8.2 years with a minimum of 5 years. Good to excellent clinical results were achieved in 93% of patients. The overall revision rate was 5.4%. Radiographically, bone ingrowth occurred in all unrevised cups, and in 95% of unrevised stems. Osteolytic lesions appeared at an average of 3.8 years postoperatively. Femoral and pelvic osteolysis were seen in 21% and 4% of the surviving hips respectively. All femoral osteolytic lesions were found in the proximal Gruen zones 1 and 7. The mean annual polyethylene wear rate was 0.15 mm. Approximately one-third of the hips were observed to have excessive wear. Our experience with cementless Omnifit total hip prosthesis is encouraging. Of significant concern is the high incidence of excessive polyethylene wear and osteolysis.

Journal Article↗