Ying-Chao Chou

Soft-tissue injury management and flap reconstruction for mangled lower extremities

SUMMARY The treatment for mangled lower extremities poses a clinical challenge for orthopaedic surgeons. The complexities of soft-tissue injury combined with open fractures and osteomyelitis have frequently resulted in amputation of the lower extremity. The current advances in soft-tissue flap reconstruction techniques have significantly improved the results of limb-salvage attempts. Understanding the reconstructive ladders around the zone of injury, debridement, timing and nuances of techniques regarding skin graft, local and distant flaps and microsurgical reconstruction is necessary to complete limb salvage in a timely and appropriate fashion. Various soft-tissue flap applications have been described, including emergent flow-through flap, acute soft-tissue flap, acute combined soft-tissue and bone flap, pedicle gastrocnemius/soleus flap, pedicle sural artery flap, soft-tissue flap for chronic osteomyelitis, composite osseous-myocutaneous flap for chronic osteomyelitis and free functioning muscle flap for functional reconstruction of mangled lower limbs. Clinical experience of 850 flaps reconstructions for mangled lower limbs in both acute and chronic stages has revealed that adequate application of flap technique was able to achieve quite acceptable results. This article provides a comprehensive review of the soft-tissue injury management and flap reconstruction for mangled lower limbs.

Treatment for scaphoid fracture and nonunion—the application of 3.0 mm cannulated screws and pedicle vascularised bone grafts

SUMMARY BACKGROUND Scaphoid fractures are very common in wrist trauma, and scaphoid nonunions with avascular necrosis are frequent complications of a fractured scaphoid. The purpose of these two retrospective studies was to examine the clinical and x-ray results of treatments for acute scaphoid fracture and scaphoid nonunion. The surgical techniques of cannulated screw fixation and pedicled vascularised bone graft are described. METHODS From 2001-2004, 80 patients with scaphoid fractures were treated with 3.0 mm cannulated screws and 5.5 mm threaded washers in our hospitals. The average age was 35 years, and the average time from injury to surgery was 16.5 hours. Outcomes were assessed by x-ray and the modified Mayo wrist score system. During the 6-year period of 1998-2004, 72 patients with scaphoid nonunions were treated using pedicled vascularised bone graft (VBG)in our hospitals. The average age was 38.5 years, and the average time from injury to surgery was 9.5 months. RESULTS The union rate was 96.25% and satisfactory function rate was 93.75% in acute scaphoid fractures with an average follow-up of 3.5 years. The union rate (90.28%) and satisfactory function rate (81.94%) achieved in scaphoid nonunions were acceptable, with an average follow-up of 5 years. CONCLUSIONS Our studies suggested that appropriate application of a cannulated screw and threaded washer was able to produce satisfactory results in scaphoid fracture, and that pedicled vascularised bone graft was effective for treating scaphoid nonunion.

Biodegradable drug-eluting nanofiber-enveloped implants for sustained release of high bactericidal concentrations of vancomycin and ceftazidime: in vitro and in vivo studies

We developed biodegradable drug-eluting nanofiber-enveloped implants that provided sustained release of vancomycin and ceftazidime. To prepare the biodegradable nanofibrous membranes, poly(D,L)-lactide-co-glycolide and the antibiotics were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. They were electrospun into biodegradable drug-eluting membranes, which were then enveloped on the surface of stainless plates. An elution method and a high-performance liquid chromatography assay were employed to characterize the in vivo and in vitro release rates of the antibiotics from the nanofiber-enveloped plates. The results showed that the biodegradable nanofiber-enveloped plates released high concentrations of vancomycin and ceftazidime (well above the minimum inhibitory concentration) for more than 3 and 8 weeks in vitro and in vivo, respectively. A bacterial inhibition test was carried out to determine the relative activity of the released antibiotics. The bioactivity ranged from 25% to 100%. In addition, the serum creatinine level remained within the normal range, suggesting that the high vancomycin concentration did not affect renal function. By adopting the electrospinning technique, we will be able to manufacture biodegradable drug-eluting implants for the long-term drug delivery of different antibiotics.

Repositioning osteotomy for intra-articular malunion of distal radius with radiocarpal and/or distal radioulnar joint subluxation.

BACKGROUND Intra-articular malunion of the distal radius may be complicated with radiocarpal and radioulnar joint subluxation, which may result in joint stiffness and loss of function. Conventional corrective osteotomy emphasizes on the restoration of the articular step-off. However, little information is available concerning the restoration of a concentric functioning joint through osteotomy. METHODS From 2002 to 2007, 12 patients with chronic intra-articular distal radius fractures were evaluated at an average follow-up of 33.6 months after repositioning osteotomy. The average time from initial injury to reconstructive operation was 11.3 months. The indication for osteotomy included dorsal or volar subluxation of the radiocarpal joint, distal radioulnar joint, or both in addition to articular incongruity. A preoperative computed tomography scan or rapid prototyping (RP) models were performed as part of the surgical planning. Operation was preceded by volar, dorsal, or both approaches. Repositioning osteotomy and internal fixation were also performed. Radiographic analysis and the Disability of Arm, Shoulder and Hand score were used for the outcome assessment. RESULTS All osteotomy sites healed and all events of radiocarpal and radioulnar subluxation were corrected. The average correction was 13.8 degrees (palmar tilt of the radius) and 1.9 mm in ulnar variance. The mean Disability of Arm, Shoulder and Hand score improved from 64 to 18. DISCUSSION Conventional corrective osteotomy via an extra-articular approach was favorably performed to correct an extra-articular malalignment or nascent intra-articular malunion. Problems of abnormal architecture after an intra-articular fracture of the radius are complicated with subluxation of carpus or distal radioulnar joint, which require repositioning via precise articular approach. Both reconstructed computed tomography images and rapid prototyping models are very useful tools in preoperative planning for intra-articular osteotomy. Simulated osteotomy and joint repositioning can be performed in solid models before commencement of actual operation. CONCLUSION Repositioning osteotomy consistently restores joint alignment and achieves functional improvement either in cases of nascent simple malunion or complex intra-articular malunion.

Dual delivery of active antibactericidal agents and bone morphogenetic protein at sustainable high concentrations using biodegradable sheath-core-structured drug-eluting nanofibers

In this study, we developed biodegradable sheath-core-structured drug-eluting nanofibers for sustainable delivery of antibiotics (vancomycin and ceftazidime) and recombinant human bone morphogenetic protein (rhBMP-2) via electrospinning. To prepare the biodegradable sheath-core nanofibers, we first prepared solutions of poly(d,l)-lactide-co-glycolide, vancomycin, and ceftazidime in 1,1,1,3,3,3-hexafluoro-2-propanol and rhBMP-2 in phosphate-buffered solution. The poly(d,l)-lactide-co-glycolide/antibiotics and rhBMP-2 solutions were then fed into two different capillary tubes controlled by two independent pumps for coaxial electrospinning. The electrospun nanofiber morphology was observed under a scanning electron microscope. We further characterized the in vitro antibiotic release from the nanofibers via high-performance liquid chromatography and that of rhBMP-2 via enzyme-linked immunosorbent assay and alkaline phosphatase activity. We showed that the biodegradable coaxially electrospun nanofibers could release high vancomycin/ceftazidime concentrations (well above the minimum inhibition concentration [MIC]90) and rhBMP-2 for >4 weeks. These experimental results demonstrate that novel biodegradable nanofibers can be constructed with various pharmaceuticals and proteins for long-term drug deliveries.

Spermatic cord myxoid liposarcoma presenting as an incarcerated inguinal hernia: report of a case and review of literatures

Incarcerated inguinal hernia is a common surgical indication in the emergency room. Delayed diagnosis can result in ischemic bowel or bowel perforation. The reported incarcerated contents include bowel loop, mesentery, omentum and, rarely, malignant lesions, such as lymphoma, metastatic tumors etc. We report a new case of primary spermatic cord liposarcoma presenting as emergent incarcerated inguinal hernia and review the related literature.

A bio-artificial poly([d,l]-lactide-co-glycolide) drug-eluting nanofibrous periosteum for segmental long bone open fractures with significant periosteal stripping injuries

Biodegradable poly([d,l]-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with two drug-to-polymer weight ratios, namely 1:3 and 1:6, which comprised PLGA 180 mg, lidocaine 20 mg, vancomycin 20 mg, and ceftazidime 20 mg, and PLGA 360 mg, lidocaine 20 mg, vancomycin 20 mg, and ceftazidime 20 mg, respectively, was produced as an artificial periosteum in the treatment of segmental femoral fractures. The nanofibrous membrane’s drug release behavior was assessed in vitro using high-performance liquid chromatography and the disk-diffusion method. A femoral segmental fracture model with intramedullary Kirschner-wire fixation was established for the in vivo rabbit activity study. Twenty-four rabbits were divided into two groups. Twelve rabbits in group A underwent femoral fracture fixation only, and 12 rabbits in group B underwent femoral fracture fixation and were administered the drug-loaded nanofibers. Radiographs obtained at 2, 6, and 12 weeks postoperatively were used to assess the bone unions. The total activity counts in animal behavior cages were also examined to evaluate the clinical performance of the rabbits. After the animals were euthanized, both femoral shafts were harvested and assessed for their torque strengths and toughness. The daily in vitro release curve for lidocaine showed that the nanofibers eluted effective levels of lidocaine for longer than 3 weeks. The bioactivity studies of vancomycin and ceftazidime showed that both antibiotics had effective and sustained bactericidal capacities for over 30 days. The findings from the in vivo animal activity study suggested that the rabbits with the artificial drug-eluting periosteum exhibited statistically increased levels of activity and better clinical performance outcomes compared with the rabbits without the artificial periosteum. In conclusion, this artificial drug-eluting periosteum may eventually be used for the treatment of open fractures.

Enhancement of tendon-bone healing via the combination of biodegradable collagen-loaded nanofibrous membranes and a three-dimensional printed bone-anchoring bolt.

A composite biodegradable polymeric model was developed to enhance tendon graft healing. This model included a biodegradable polylactide (PLA) bolt as the bone anchor and a poly(D,L-lactide-co-glycolide) (PLGA) nanofibrous membrane embedded with collagen as a biomimic patch to promote tendon–bone interface integration. Degradation rate and compressive strength of the PLA bolt were measured after immersion in a buffer solution for 3 months. In vitro biochemical characteristics and the nanofibrous matrix were assessed using a water contact angle analyzer, pH meter, and tetrazolium reduction assay. In vivo efficacies of PLGA/collagen nanofibers and PLA bolts for tendon–bone healing were investigated on a rabbit bone tunnel model with histological and tendon pullout tests. The PLGA/collagen-blended nanofibrous membrane was a hydrophilic, stable, and biocompatible scaffold. The PLA bolt was durable for tendon–bone anchoring. Histology showed adequate biocompatibility of the PLA bolt on a medial cortex with progressive bone ingrowth and without tissue overreaction. PLGA nanofibers within the bone tunnel also decreased the tunnel enlargement phenomenon and enhanced tendon–bone integration. Composite polymers of the PLA bolt and PLGA/collagen nanofibrous membrane can effectively promote outcomes of tendon reconstruction in a rabbit model. The composite biodegradable polymeric system may be useful in humans for tendon reconstruction.

Development of a Three-Dimensional (3D) Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft

This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D) printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire) fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

Biodegradable nanofiber-membrane for sustainable release of lidocaine at the femoral fracture site as a periosteal block: In vitro and in vivo studies in a rabbit model

The aim of this study was to evaluate the efficacy of a biodegradable, lidocaine-embedded, nanofibrous membrane for the sustainable analgesic release onto fragments of a segmental femoral fracture site. Membranes of three different lidocaine concentrations (10%, 30%, and 50%) were produced via an electrospinning technique. In vitro lidocaine release was assessed by high-performance liquid chromatography. A femoral segmental fracture, with intramedullary Kirschner-wire fixation and polycaprolactone stent enveloping the fracture site, was set-up in a rabbit model for in vivo assessment of post-operative recovery of activity. Eighteen rabbits were randomly assigned to three groups (six rabbits per group): group A comprised of rabbits with femoral fractures and underwent fixation; group B comprised of a comparable fracture model to that of group A with the implantation of lidocaine-loaded nanofibers; and group C, the control group, received only anesthesia. The following variables were measured: change in body weight, food and water intake before and after surgery, and total activity count post-surgery. All membranes eluted effective levels of lidocaine for more than 3 weeks post-surgery. Rabbits in group B showed faster recovery of activity post-operatively, compared with those in group A, which confirmed the pain relief efficacy of the lidocaine-embedded nanofibers. Nanofibers with sustainable lidocaine release have adequate efficacy and durability for pain relief in rabbits with segmental long bone fractures.