Shew Ping Chow

The use of rapid prototyping to assist medical applications

Purpose – This paper aims to illustrate a number of instances where RP and associated technology has been successfully used for medical applications.Design/methodology/approach – A number of medical case studies are presented, illustrating different uses of RP technology. These studies have been analysed in terms of how the technology has been applied in order to solve related medical problems.Findings – It was found that RP has been helpful in a number of ways to solve medical problems. However, the technology has numerous limitations that have been analysed in order to establish how the technology should develop in the future.Practical implications – RP can help solve medical problems, but must evolve if it is to be used more widespread in this field.Originality/value – This paper has shown a number of new applications for RP, providing a holistic understanding how the technology can solve medical problems. It also identifies a number of ways in which the technology can improve in order to better solve ...

Palmar Plate Fixation of AO Type C2 Fracture of Distal Radius Using a Locking Compression Plate –A Biomechanical Study in a Cadaveric Model

The stability of palmar plate fixation using a locking compression T-plate was compared with that of a conventional palmar T-plate and a dorsal T-plate in a cadaveric model of an AO type C2 fracture of distal radius. The wrist axial load transmission through the radius was tested for each fixation. The results show that, under 100N axial load, the palmar locking compression T-plate restores stability comparable to that of the intact radius, and is superior to conventional palmar or dorsal T-plates.

A prospective, randomized trial comparing the limited contact dynamic compression plate with the point contact fixator for forearm fractures.

BACKGROUND The most effective type of plate fixation for diaphyseal forearm fractures has not been defined. We performed a prospective, randomized trial in which the limited contact dynamic compression plate (LC-DCP) was compared with the Point Contact Fixator (PC-Fix) for the treatment of forearm fractures at one center. METHODS Ninety-two patients with 125 forearm fractures were recruited for the study and were randomly assigned to fracture fixation with one of the two devices. The average age of the patients was thirty-six years. The average duration of follow-up was twenty-two months. Patients were assessed periodically with use of radiographs and were assessed with regard to pain and function at time of the latest follow-up. RESULTS Three patients (four fractures) in the PC-Fix group and five patients (five fractures) in the LC-DCP group had a delayed union, but no patient in either group had a nonunion. With the numbers available, there was no significant difference between the two groups with regard to operative time, time to union, callus formation, pain, or functional outcome. Deep infection occurred in one patient with a closed fracture in the PC-Fix group and in one patient with an open fracture in the LC-DCP group. In addition, one refracture occurred in each group. Both refractures occurred at the site of a screw track. CONCLUSION Despite the differences in the concept of fracture fixation, these two implants appear to be equally effective for the treatment of diaphyseal forearm fractures.

Limited open reduction and Ilizarov external fixation in the treatment of distal tibial fractures

The authors reviewed 31 distal tibial fractures (16 involving the tibial plafond) treated with Ilizarov external fixation. The study population was composed of 19 males and 12 females, with an average age of 54. The fractures were classified according to the AO classification: A1 (3), A2 (6), A3 (6), C1 (2), C2 (8), C3 (6). There were six open injuries. In 14 pilon cases, open reduction of the intra-articular fragments and bone grafting via a limited incision was performed. Clinical follow-up averaged 28 months (range 18-42). All but one fracture united with an average healing time of 13.9 weeks. Nearly all patients with AO type A fracture had excellent or good functional scores. The 14 cases of AO C2 and C3 group had five (38%) good results, five (38%) fair results and three (24%) poor results. This method yielded results comparable with previous studies using open reduction and internal fixation. Twenty-nine percent of the patients had pin track infection, which remained the most important complication of this method.

Treatment of distal femoral fractures in the elderly using a less-invasive plating technique

We treated 16 patients having fractures of the distal femur with the less-invasive stabilization system (LISS). Patients’ mean age was 75 (62–101) years. Fifteen patients had low-energy trauma. Eight fractures were type A (AO classification), three were type B and five were type C. In two cases, loosening of the proximal fixation was seen and surgical revision performed. Union time averaged 30 (16–68) weeks. There was no non-union. Average Oxford knee score was 46 (22–60). No loosening of the distal fixation was found. LISS appears to be an effective device in treating osteoporotic distal femoral fractures.RésuméNous avons traité 16 malades présentant une fracture fémorale distale avec le Système de Stabilisation peu Invasif (LISS). L’âge moyen des malades était de 75 ans (62–101). Quinze malades avaient eu un traumatisme à basse énergie. Huit fractures étaient de type A (classification AO), trois étaient de type B, et cinq étaient de type C. Dans deux cas un démontage de la fixation proximale est survenu, avec nécessité de reprise chirurgicale. Le délai moyen de consolidation était de 30 semaines (16–68). Il n’y avait aucune non—consolidation. Le score moyen de genou Oxford était 46 (22–60). Il n’y a eut aucun démontage de la fixation distale. Le système LISS paraît être une méthode efficace pour traiter les fractures fémorales distales ostéoporotiques.

Does timing of surgery matter in fragility hip fractures

The effect of delay of surgery on the geriatric hip fractures has been a subject of interest in the past two decades. While the elderly patients will not tolerate long periods of immobilization, it is still unclear how soon these surgeries need to be performed. A review of existing literature was performed to examine the effect of timing of surgery on the different outcome parameters of these patients. Although there is conflicting evidence that early surgery would improve mortality, there is widespread evidence in the literature that other outcomes including morbidity, the incidence of pressure sores, and the length of hospital stay could be improved by shortening the waiting time of hip fracture surgery. We concluded that it is beneficial to the elderly patients to receive surgical treatment as an urgent procedure as soon as the body meets the basic anesthetic requirements.

Nicolau syndrome following intramuscular diclofenac administration: a case report.

Nicolau syndrome (livedoid dermatitis) is a rare adverse reaction of a still largely unidentified pathogenesis at the site of intramuscular drug injection. The typical presentation is pain around the injection site soon after injection, followed by erythema, livedoid patch, haemorrhagic patch, and finally necrosis of skin, subcutaneous fat, and muscle tissue. The phenomenon has been related to the administration of a variety of drugs, including non-steroidal anti-inflammatory drugs, corticosteroids, and penicillin. We report a case of Nicolau syndrome following an intramuscular injection of diclofenac. The large ulceration over the right buttock was positive for Pseudomonas aeruginosa, and histology revealed subcutaneous fat necrosis and non-specific inflammation with no evidence of malignancy or vasculitis. The lesion required multiple debridements and a partial-thickness skin graft. Subcutaneous injection, rather than intramuscular injection, was found to be a determining factor in this case. Clinicians must be cautious in the use of proper injection procedures, including appropriate needle length, in order to minimise complications.

Locking Compression Plate in the Treatment of Forearm Fractures: A Prospective Study:

Purpose. To evaluate the use of locking compression plates (LCPs) in diaphyseal forearm fractures. Methods. 9 women and 23 men (mean age, 35; range, 12–70 years) with 45 forearm fractures were treated by open reduction and internal fixation with 3.5-mm stainless steel LCPs. All patients were followed up monthly until union; the mean duration being 20 months. Radiographic assessment was performed at 3, 6, 12, and 18 months. Clinical assessments regarding pain and function were undertaken at the final follow-up. Results. Two patients had delayed union but none had nonunion. There was no deep infection and only one superficial infection. Two refractures occurred after implant removal, both were of simple transverse type and at the sites of the original fractures. 33% of the fractures were reduced anatomically. 56% of the fractures healed with no or minimal callus formation and 44% with moderate callus formation. In total, 13% of the anatomically reduced fractures had moderate or abundant callus formation. 22 patients opted for removal of the implants (29 LCPs), after a mean of 16 (range, 9–21) months. Conclusion. The LCP is an effective bridging device used for treating comminuted fractures, but for treating simple fractures its superiority over conventional plating is yet to be proven.

Mycobacterium marinum infection of the hand and wrist

Purpose. To review records of 166 patients who underwent treatment for Mycobacterium marinum tenosynovitis of the hand and wrist to identify factors associated with functional outcome. Methods. Records of 97 men and 69 women aged 13 to 85 (mean, 50) years who underwent treatment for suspected M marinum tenosynovitis of the hand and wrist were retrospectively reviewed. All underwent open biopsy; synovectomy was performed when florid synovitis was present. Rifampicin and ethambutol were usually prescribed. Clarithromycin, minocycline and/or levofloxacin were used as adjuvants if there was drug intolerance, allergy, or relapse. The duration of antibiotic treatment depended on the clinical recovery. Patients were followed up for one year after completion of drug treatment. Functional outcome was considered excellent for those with >195° total active motion (TAM) and >75% return of motion, good for those with 130° to 195° TAM and 50 to 75% return of motion, fair for those with 65° to 129° TAM and 25 to 49% return of motion, and poor for those with <65° TAM and <25% return of motion. Results. The mean delay in presentation was 4.9 (0.3–120) months. 93 of the patients presented with disabilities (fexion deformity or reduced range of motion), 64 of whom presented one month after injury. 37 (22%) of the patients had received intralesional steroids prior to admission, 30 of whom presented one month after injury. 32 (19%) patients were treated with antibiotics alone, whereas 134 (81%) patients underwent debridement in addition to antibiotic treatment. The mean duration of antibiotic treatment was 7.2 (range, 0–29) months. Of the 156 patients who completed the follow-up, functional outcome was satisfactory in 128 (82%) and unsatisfactory in 28 (17%). Steroid injections and late presentation led to worse functional outcome. Patients with unsatisfactory outcome were more likely to have received intralesional steroid injections (43% [16/37] vs. 10% [12/118], p<0.001, Pearson Chi squared test), have presented >2 months after injury (27% [21/79] vs. 9% [7/77], p=0.004, Pearson Chi squared test), and have undergone synovectomy (23% [28/124]) vs. 0% [0/32], p=0.001, Fishers exact test). Worse functional outcome correlated with late presentation (r=0.218) and the greater number of debridement procedures (r=0.453). Conclusion. Delayed antibiotic treatment of M marinum infections and steroid injections were associated with unsatisfactory outcome. Clinicians must have a high index of suspicion for this condition and avoid inappropriate management such as intralesional steroid injections. Public awareness to this condition should be raised.

Open reduction and plate fixation of displaced AO type C3 fractures of the Distal radius: Restoration of Articular congruity in Eighteen cases

Objective To determine the ability of open reduction and plate fixation to restore articular congruity in the treatment of fractures of the distal radius with intraarticular comminution and displacement. Design Prospectively followed series. Methods Eighteen consecutive fractures of the distal radius with intraarticular comminution and displacement were treated with open reduction and combined volar and dorsal plate fixation in thirteen, dorsal plate fixation in four, and volar plate fixation in one case. Kirschner wires were added in thirteen fractures and cancellous bone graft was used in four fractures. Articular congruity after a mean follow-up of twenty-three months was assessed using anteroposterior and lateral radiographs. Results Articular congruity without a two millimeter or more intraarticular stepoff was found at follow-up in fifteen of eighteen cases, without a two millimeter or more gap in nine cases and without a two millimeter or more stepoff or gap in only eight cases. One reason for not having obtained articular congruity in some of the fractures was insufficient intraoperative visualization of the joint surface. Three reduced fractures redisplaced. The reason for loss of intraarticular reduction was considered insufficient stabilization of the distal fragments. In two of the three cases, it was thought that insertion of bone graft would have prevented the loss of reduction. Conclusions Articular incongruity after open reduction and plate fixation of comminuted fractures of the distal radius may occur more often than expected. The reduced fracture should be evaluated by intraoperative radiographs. If the reduced joint surface is not entirely visible on the radiographs because of implants or other reasons, oblique radiographs or fluoroscopy should be additionally used. Plate fixation alone does not always provide sufficient stability and cancellous bone graft should be added in cases of metaphyseal bone loss or for stabilization of multiple small articular fragments that cannot be fixed by screws or Kirschner wires.