Robert Wen-Wei Hsu

Normal axial alignment of the lower extremity and load-bearing distribution at the knee.

Based on a series of 120 normal subjects of different gender and age, the geometry of the knee joint was analyzed using a full-length weight-bearing roentgenogram of the lower extremity. A special computer program based on the theory of a rigid body spring model was applied to calculate the important anatomic and biomechanical factors of the knee joint. The tibiofemoral mechanical angle was 1.2 degrees varus. Hence, it is difficult to rationalize the 3 degree varus placement of the tibial component in total knee arthroplasty suggested by some authors. The distal femoral anatomic valgus (measured from the lower one-half of the femur) was 4.2 degrees in reference to its mechanical axis. This angle became 4.9 degrees when the full-length femoral anatomic axis was used. When simulating a one-legged weight-bearing stance by shifting the upper-body gravity closer to the knee joint, 75% of the knee joint load passed through the medial tibial plateau. The knee joint-line obliquity was more varus in male subjects. The female subjects had a higher peak joint pressure and a greater patello-tibial Q angle. Age had little effect on the factors relating to axial alignment of the lower extremity and load transmission through the knee joint.

FREE VASCULARISED FIBULAR GRAFTING FOR RECONSTRUCTION AFTER TUMOUR RESECTION

We have reviewed 30 patients at a mean of 36 months after free vascularised fibular transfer to reconstruct massive skeletal defects after resection of primary bone tumours. There were 23 malignant and 7 benign neoplasms, half in the lower limb and half in the upper. Arthrodesis was performed in 15 and intercalary bone replacement in 15. The mean fibular graft length was 189 mm. Union was achieved in 27 (90%) at an average of 7.6 months, and the 3-year survival was 89%. There was a high complication rate (50%), but most resolved without greatly influencing the final outcome. There was local recurrence in two (6.7%), but 16 of the 24 assessed patients (67%) had satisfactory functional results. This is a reasonably effective means of reconstruction for limb salvage after resection of tumours.

Knee dislocation : Treatment of high-velocity knee dislocation

BACKGROUND We report the outcomes of patients treated with a new arthroscopic treatment modality for knee dislocation after high-velocity trauma. METHODS Twenty-three patients (12 men, 11 women; 25 knees) with traumatic knee dislocation were treated with this technique. Under arthroscopy with gravity inflow irrigation, the ruptured posterior cruciate ligament was reconstructed with a patellar bone-tendon-bone graft, and the anterior cruciate ligament was debrided subacutely. The collateral ligament, meniscus, and capsules were repaired through additional incisions. RESULTS The average interval between injury and surgery was 11.1+/-5 days (range, 5 to 25 days). After a mean follow-up period of 27.2+/-7.86 months, the mean extension was 1+/-2 degrees and the average flexion was 129.6+/-4.91 degrees. The mean Lysholm score was 84. There were no major complications. CONCLUSION Arthroscopic posterior cruciate ligament reconstruction seems to be an effective treatment for traumatic knee dislocation.

Complications in thoracoscopic spinal surgery: a study of 90 consecutive patients.

AbstractBackground: The literature contains few reports on negative outcomes after thoracoscopic spinal surgery. Methods: From November 1995 to February 1998, 90 patients underwent minimally invasive spinal surgery by thoracoscopic assistance as treatment for their anterior spinal lesions. The diagnoses included 41 spinal metastases, 13 cases of scoliosis, 12 burst fractures, 10 cases of tuberculous spondylitis, 8 cases of pyogenic spondylitis, 2 thoracic disc herniations, 2 cases of ankylosing spondylitis with discitis, 1 osteoporotic compression fracture, and 1 case of thoracolumbar kyphosis. The procedures included biopsy only (3 patients); thoracic discectomy (3 patients); multilevel anterior releases, discectomy, and fusion (14 patients); corpectomy for decompression (6 patients); corpectomy and interbody fusion (32) patients; and internal instrumentation (28 patients). Results: A total of 30 complications were noted in 22 patients (24.4%). Two fatal complications occurred, resulting from massive blood transfusion in one case and postoperative pneumonia in another. Other nonfatal complications included four cases of transient intercostal neuralgia, three superficial wound infections, three cases of pharyngeal pain, two cases of lung atelectasis, two cases of residual pneumothorax, two cases of subcutaneous emphysema, one inadvertent pericardial penetration due to adhesion, one chylothorax that resolved after conservative management, one vertebral screw malposition, and one graft dislodgement that needed late revision surgery. Three patients required ventilatory support for longer than 72 hours. Five patients with spinal metastases had an estimated intraoperative blood loss of more than 2,000 ml. No injury to the internal organs or spinal cord was observed. There were four conversions to open procedures due to two cases of severe pleural adhesions and two poorly tolerated one-lung ventilation. At the latest follow-up, nine patients had died as a result of cancer dissemination. Conclusions: (a) Well-selected patients and attention to details are essential to optimizing surgical results. (b) A refined technique for less invasive tumor surgery has been developed. (c) Surgeons had better experience with the standard anterior spinal approach and showed no hesitation in converting to an open procedure when necessary. A procedure failure does not mean a treatment failure.

Treatment of osteomyelitis with teicoplanin-encapsulated biodegradable thermosensitive hydrogel nanoparticles.

Osteomyelitis characterized by an inflammatory response often leads to bone loss and the spread of bacterial infection to surrounding soft tissues. To overcome the side effects induced by the systemic antibiotic treatment for osteomyelitis, recent investigations have explored the use of antibiotic-loaded undegradable or biodegradable delivery implants at the infected bone. Here, we show a novel biodegradable thermosensitive implant composed of poly(ethylene glycol) monomethyl ether (mPEG) and poly(lactic-co-glycolic acid) (PLGA) copolymer as a sol-gel drug delivery system for treating bone infection. The physical properties of a series of mPEG-PLGA nanocomposites, including the critical micelle concentration (CMC), particle size, polyindex (PI), sol-gel transition, viscosity and degradation rate, have been characterized in vitro. This sol-to-gel drug delivery system could provide several advantages in treating osteomyelitis, including easy preparation, 100% encapsulated rate, near-linear sustained release of drugs, injectable design and in situ gelling at the target tissue. Similar to the undegradable teicoplanin-impregnated polymethylmethacylate (PMMA) bone cements, we showed that implantation of the mPEG-PLGA hydrogel containing teicoplanin was effective for treating osteomyelitis in rabbits as detected by the histological staining and immunoblotting analyses. The use of the mPEG-PLGA-based biodegradable hydrogels may hold great promise as a therapeutic strategy for other infected diseases.

Comparison of Computer-Assisted Navigation and Conventional Instrumentation for Bilateral Total Knee Arthroplasty

This prospective study analyzed computer-assisted surgery (CAS) navigation and conventional instrumentation in bilateral total knee arthroplasty. Sixty patients underwent CAS navigation in 1 knee and conventional instrumentation in the contralateral knee randomly. The target zone resided in the reconstructed mechanical axis within a range of 3 degrees varus or valgus. The reconstructed mechanical axes in the CAS navigation group were significantly closer to planned axes than those in the conventional group. Average blood loss in the CAS navigation group was lower, whereas mean tourniquet time was longer than in the conventional group. No surgery-related complications existed in either group. The results indicate that, despite longer operative time, CAS navigation total knee arthroplasty is a safe procedure and outperforms conventional technique in accuracy of leg axes.

Necrotizing soft-tissue infections and sepsis caused by Vibrio vulnificus compared with those caused by Aeromonas species

BACKGROUND Vibrio and Aeromonas species, which can cause necrotizing fasciitis and primary septicemia, are members of the Vibrionaceae family and thrive in aquatic environments. Because the clinical symptoms and signs of necrotizing fasciitis and sepsis caused by these two bacteria are similar, the purposes of this study were to describe the clinical characteristics of Vibrio vulnificus and Aeromonas infections, to analyze the risk factors for death, and to compare the effects of surgical treatment on the outcome. METHODS The cases of thirty-two patients with necrotizing soft-tissue infections and sepsis caused by Vibrio vulnificus (seventeen patients) and Aeromonas species (fifteen patients) were retrospectively reviewed over a four-year period. Surgical débridement or immediate limb amputation was initially performed in all patients. Demographic data, underlying diseases, laboratory results, and clinical outcome were analyzed for each patient in both groups. RESULTS Six patients in the Vibrio vulnificus group and four patients in the Aeromonas group died. The patients who died had significantly lower serum albumin levels than did the patients who survived (p < 0.05). The patients with a combination of hepatic dysfunction and diabetes mellitus had a higher mortality rate than those with either hepatic disease or diabetes mellitus alone (p < 0.05). The patients with Vibrio vulnificus infections had a significantly lower systolic blood pressure at presentation (p = 0.006). The patients with Aeromonas infections who died had significantly lower white blood-cell counts (p = 0.03) with significantly fewer numbers of segmented white blood cells than those who died in the Vibrio vulnificus group (p = 0.01). CONCLUSIONS The contact history of patients with a rapid onset of cellulitis can alert clinicians to a differential diagnosis of soft-tissue infection with Vibrio vulnificus (contact with seawater or raw seafood) or Aeromonas species (contact with fresh or brackish water, soil, or wood). Early fasciotomy and culture-directed antimicrobial therapy should be aggressively performed in those patients with hypotensive shock, leukopenia, severe hypoalbuminemia, and underlying chronic illness, especially a combination of hepatic dysfunction and diabetes mellitus.

Effect of shock‐wave therapy on patellar tendinopathy in a rabbit model

This study investigated the effect of shock‐wave therapy (SWT) on collagenase induced tendinopathy in the rabbit patellar tendon. Eighteen rabbits were treated by ultrasonography‐guided injection of 0.025 ml collagenase into the patellar tendon in both knees. After tendinopathy was confirmed at 3 weeks post‐treatment by the histological examination, SWT was initiated to the right patellar tendon involving 1500 cycles at 0.29 mJ/mm2 in two separated weekly courses from 4 weeks post‐treatment. The rabbits were randomly divided into two groups, which were sacrificed at the 4th and 16th week after SWT, respectively. The histological examination, the mechanical and biochemical tests then were performed. The ultimate tensile load in the SWT tendon increased 7.03% at 4 week and 10.34% at 16 week after treatment as compared to the sham group. Hydroxyproline concentrations increased in the SWT tendons over both the 4 and 16 weeks after treatment. Moreover, the pyridinoline concentration increased at the 4th week but decreased at 16th week as compared to the sham group. The histological examination demonstrated increased blast‐like tenocyte at the 4th week, while more mature tenocyte with neovasculization at the 16th week. The result obtained here validates the effectiveness of the SWT in the established tendinopathy. SWT may increase collagen synthesis and collagen crosslink formation during early healing process.

Pulmonary function after thoracoplasty in adolescent idiopathic scoliosis.

The current study evaluated sequential pulmonary function tests prospectively at a minimum of 2 years after thoracoplasty in adolescent patients with idiopathic scoliosis. Twenty patients were divided into two groups: Group I (n=12) was comprised of patients who had posterior instrumented fusion with external thoracoplasty, and Group II (n=8) was comprised of patients who in addition to a posterior instrumented fusion, had an anterior release and fusion via video-assisted thoracoscopic surgery (n=4) or open thoracotomy (n=4) because of rigid severity. Forced vital capacity and forced expiratory volume in 1 second of percent predicted values in Group I declined 9% at 3 months postoperatively and returned to the preoperative baseline at 1 year. However, forced vital capacity and forced expiratory volume in 1 second of percent predicted values in Group II declined 11% to 18% postoperatively and did not return to the preoperative baseline at 2 years. Posterior instrumented fusion with thoracoplasty in adolescent patients with idiopathic scoliosis significantly decreased pulmonary function at 3 months, but returned to the preoperative baseline at 1 year. The addition of an anterior releasing procedure resulted in poorer pulmonary function, which did not return to the preoperative baseline by the 2-year followup.

Traumatic patellar tendon ruptures: a follow-up study of primary repair and a neutralization wire.

Thirty-five patients with traumatic patellar tendon ruptures treated with primary repair and neutralization wire were retrospectively reviewed. The length of follow up ranged from 1.5 years to 5 years with an average follow up period of 20 months. All the ruptures occurred due to acute trauma, twelve of them (34%) involved in a multiple injuries, and nineteen had an open wounds around the knee joints. The diagnostic clues included a high riding patella by palpation or by X-ray, hemoarthrosis, a palpable gap over the tendon; and being unable to extend the knee actively. Using the criteria of Siwek and Rao, at follow up 57% were rated as excellent, 28.6% good; and 14.2% unsatisfactory. None of the 35 patients had a rerupture of tendon. It is recommended that primary repair with a neutralization wire can be a treatment of choice for traumatic patellar tendon ruptures.