Development and Validation of a Low-Cost Drilling Model.

Background: Simulation models enable learners to have repeated practise at their own time, to master the psycho-motor and sensory acuity aspects of surgery and build their confidence in the procedure. The study aims to develop and evaluate the feasibility of a low-cost drilling model to train surgeons in the drilling task. The model targets three aspects of drilling - (1) Reduce plunge depth, (2) Ability to differentiate between bone and medullary canal and (3) Increase accuracy drilling in various angles. Methods: This cross-sectional study was conducted after obtaining ethics approval. We invited Consultants in the field of Orthopaedic or Hand Surgery to form the 'expert' group, and the 'novice' group consisted of participants who had no prior experience in bone drilling. We developed a drilling simulator model made from a polyvinyl chloride (PVC) pipe filled with liquid silicone. This model cost less than US$5. An electric Bosch drill (model GBM 10 RE) with a 1.4 mm K-wire 10 cm in length (6.5 cm outside the drill) was used for drilling. The main outcomes of the study were time taken for drilling, plunge depth, ability to penetrate the far cortex and accuracy. Results: Thirty-one participants were recruited into the study, of which 15 were experts and 16 were novices. The experts performed significantly better for plunge depth (t = -3.65, p = 0.0003) and accuracy (t = -2.07, p = 0.04). The experts required 20% less time to complete the drilling tasks, but it was not statistically significant (t = -0.79, p = 0.43). Conclusions: The low-cost drilling model could be useful in training Residents in the drilling task. It will allow Residents to practise independently at their own time and assess their own performance.

Chicken Feet: A Model for Practising Locoregional Flaps of the Hand.

Background: The aim of this study was to determine the feasibility of the chicken foot model for surgical trainees interested in practising the designing, harvesting and inset of locoregional flaps of the hand. Methods: A descriptive study was performed to demonstrate the technical aspects of harvesting four locoregional flaps in a chicken foot model: fingertip volar V-Y advancement flap, four-flap and five-flap Z-plasty, cross-finger flap and first dorsal metacarpal artery (FDMA) flap. The study was performed in a surgical training laboratory on non-live chicken feet. No participants were involved in this study, apart from authors performing the descriptive techniques. Results: All flaps were successfully performed. Anatomical landmarks, soft tissue texture and flap harvest, as well as inset closely resembled clinical experience with patients. Maximal flap sizes were 12 × 9 mm for volar V-Y advancement, 5 mm limbs for Z-plasties, 22 × 15 mm for cross-finger flaps and 22 × 12 mm for FDMA flaps. The maximal webspace deepening with four-flap/five-flap Z-plasty was 20 mm and the FDMA pedicle length and diameter was 25 and 1 mm, respectively. Conclusions: Chicken feet can be effectively used as simulation models for hand surgical training with respect to gaining familiarity with the use of locoregional flaps of the hand. Further research requires testing for reliability and validity of the model on junior trainees.

Pedicled Osteo-Onchyocutaneous Island Flap for Finger Macrodactyly: A Review of Literature.

We present a case of middle finger macrodactyly reconstructed in a single stage using multiple techniques. We elevated a pedicled osteo-onychocutaneous island flap, excised the remnant distal phalanx with a segment of 1 digital nerve and skin over the dorsum of the middle phalanx, performed epiphysiodesis and reduction of the middle phalanx as well as soft-tissue debulking, and inset the flap over the dorsum of the middle phalanx. Follow-up at 12 months revealed a satisfactory aesthetic and functional outcome.

3D-printed Poly-Lactic Co-Glycolic Acid (PLGA) scaffolds in non-critical bone defects impede bone regeneration in rabbit tibia bone.

BACKGROUND: An increasing number of bone graft materials are commercially available and vary in their composition, mechanism of action, costs, and indications. OBJECTIVE: A commercially available PLGA scaffold produced using 3D printing technology has been used to promote the preservation of the alveolar socket after tooth extraction. We examined its influence on bone regeneration in long bones of New Zealand White rabbits. METHODS: 5.0-mm-diameter circular defects were created on the tibia bones of eight rabbits. Two groups were studied: (1) control group, in which the bone defects were left empty; (2) scaffold group, in which the PLGA scaffolds were implanted into the bone defect. Radiography was performed every two weeks postoperatively. After sacrifice, bone specimens were isolated and examined by micro-computed tomography and histology. RESULTS: Scaffolds were not degraded by eight weeks after surgery. Micro-computed tomography and histology showed that in the region of bone defects that was occupied by scaffolds, bone regeneration was compromised and the total bone volume/total volume ratio (BV/TV) was significantly lower. CONCLUSION: The implantation of this scaffold impedes bone regeneration in a non-critical bone defect. Implantation of bone scaffolds, if unnecessary, lead to a slower rate of fracture healing.

Emergency Hand and Reconstructive Microsurgery in the COVID-19-Positive Patient.

The case spectrum in hand surgery is one of extremes-purely elective day surgery cases under local anesthesia to mangling limb injuries that require immediate, and frequently, lengthy, surgery. Despite the cancellation of most elective orthopedic and plastic surgical procedures, hand surgeons around the world continue to see a steady stream of limb-threatening cases such as severe trauma and infections that require emergent surgical care. With the increase in community-spread, an increasing number of COVID-19-infected patients may be asymptomatic or have mild, nonspecific or atypical symptoms. Some of them may already have an ongoing, severe infection. The time-sensitive nature of some of these cases means that hand surgeons may need to operate urgently on patients who may be suspected of COVID-19 infections, often before confirmatory test results are available. General guidelines for perioperative care of the COVID-19-positive patient have been published. However, our practices differ from those of general orthopedic and plastic surgery, primarily because of the focus on trauma. This article discusses the perioperative and technical considerations that are essential to manage the COVID-19 patient requiring emergency care, without compromising clinical outcomes and while ensuring the safety of the attending staff.

Outcomes of Phalangeal Neck Fractures in a Pediatric Population.

PURPOSE: Displaced pediatric phalangeal neck fractures are regarded as unstable, and hence, surgical fixation is traditionally recommended. In our experience, some patients with displaced fractures treated nonsurgically healed with a good clinical outcome and no further displacement. We studied the outcome of displaced phalangeal neck fractures treated nonsurgically with attention to the change in fracture displacement over time and hypothesized that displaced phalangeal neck fractures can be treated nonsurgically with maintenance of acceptable radiological parameters. METHODS: A retrospective review of 35 patients aged 16 and younger was conducted. Included patients had at least 10° of angulation or 25% translation in either the coronal or the sagittal plane, with no malrotation. Angulation and translation of the distal fracture fragment in the coronal and sagittal planes was measured from radiographs taken at 2 intervals-within 7 days of the injury and at least 21 days after the injury. Initial and final measurements were compared to determine the amount of fracture displacement that occurred. RESULTS: Thirty-five patients with type II A, B, and C fractures (classification according to Al-Qattan) comprised our study sample. Twelve patients had undergone manipulation and reduction. Average radiological follow-up was 4.3 months (range, 0.7-86 months; median, 1.2 months; SD, 14.7). These fractures treated nonsurgically did not displace as the fracture healed, suggesting that type II fractures, although traditionally regarded as unstable, may maintain their radiological parameters without surgical fixation. CONCLUSIONS: Our findings suggest that displaced phalangeal neck fractures do not necessarily displace with nonsurgical treatment. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Retrograde Flow Digital Artery Flaps.

Retrograde flow digital artery flaps are a versatile single-stage option for the coverage of fingertip and dorsal digit defects. There are technical challenges associated with pedicle dissection and preparation. Techniques vary predominantly in the vessel utilized (either the proper digital artery or its branches) and the incorporation of the digital nerve or its branches in the pedicle with subsequent neurorrhaphy. Venous failure is more common. There is often mild but perceivable donor site morbidity. Evidence favors an innervated flap for better sensory recovery. Cold intolerance follows sacrifice of a digital artery.

Maximal advancement of homodigital neurovascular island flaps.

We investigated the maximal advancement of the homodigital neurovascular island flap with the digit in full extension and its correlation to the digital length. In 32 adult cadaveric digits, flaps measuring 1 × 1 cm were sequentially elevated to different dissection points. Dissection of the flap to the proximal interphalangeal joint crease, palmo-digital crease, division of adjacent digital artery and the superficial arch resulted in flap advancement of 8, 12, 15 and 18 mm, respectively. The degree of advancement correlated to the length of the finger and was approximately 19% of the finger length. We conclude that dissection of a homodigital antegrade neurovascular island flap to the proximal interphalangeal joint, palmo-digital crease, after ligation of adjacent digital artery and the superficial arch allows progressively more advancement. The advancement obtained by flap dissection to the palmo-digital crease was about 19% of the finger length.

Surmounting the Learning Curve of Core Suture Placement with Tendon Repair Simulator.

BACKGROUND: Attaining competency in placement of core suture with adequate distance from juncture is a key skill for learners of tendon repair. Currently, this is most commonly practiced on animal models in wet laboratory environment. To improve accessibility and availability, we developed a tendon repair trainer that aims to guide learners in obtaining this key competency. METHODS: A customized tendon dock was designed and manufactured with additive method that permits insertion of 6mm silicon tendon rods to simulate flexor tendon repair along a digit. Four residents, divided into two groups, were instructed to repair two sets of tendon rods (60 rods per resident) with Kessler suture loop placed at 10 mm from juncture (Group A: rods marked at 10 mm, Group B: unmarked rods). The main criterion for passing was a loop placed within 1 mm of the target distance (10 mm). At a second session, both groups repaired unmarked tendons, and these were marked based on similar criterion. RESULTS: At the first session, 100% of those who repaired marked rods (Group A) passed while 25% of unmarked rods (Group B) attained a pass. At the second session, where both groups repaired unmarked rods, residents from group A achieved a pass rate of 95% while group B achieved 33.3% pass. CONCLUSIONS: Learners who had previously repaired marked rods were able to retain their experience when repairing unmarked rods. This suggest that the proposed model may be a helpful adjunct to sharpen learners' skills prior to practicing tendon repairs in more costly animal or cadaveric models.

Post-Reduction Stability of the Proximal Interphalangeal Joint after Dorsal Fracture Dislocation-A Cadaveric Study.

BACKGROUND: Proximal interphalangeal joint (PIPJ) dorsal fracture dislocations (DFD) are challenging injuries. Treatment aims to achieve stability of the PIPJ after reduction so that early motion can be initiated. We studied how increasing articular destruction would affect post reduction stability and investigate the amount of traction and PIPJ flexion needed to maintain the reduction. METHODS: Increasing amounts (20%, 40% and 60%) of damage to the volar lip of the middle phalanx in cadaveric specimens were created to represent PIPJ DFD that were stable, of tenuous stability and frankly unstable. Traction forces and PIPJ flexion needed to maintain the reduction were then measured. RESULTS: The PIPJ DFD with 20% damage were stable and did not subluxe while the one with 40% articular involvement was stable after reduction. For unstable the PIPJ with 60% involvement, the more the PIPJ was flexed, the less traction force was needed to hold the joint in reduction. For PIPJ flexion of 20 degrees, a minimum 4.4N of force is needed to maintain reduction while PIPJ flexion of 10 degrees required a minimum 5.0N of force. No amount of force could maintain PIPJ reduction if traction was performed in full extension. CONCLUSIONS: In our model, PIPJ DFD with less than 30% articular damage are stable while those with 30% to 50% of involvement have tenuous stability. For the unstable PIPJ DFD, traction obviates the need for excessive flexion of the PIPJ to maintain joint reduction. This information should be considered in treatment modalities for PIPJ DFD, as well in the design of external traction devices for the treatment of PIPJ DFD.

Characteristics of Fingertip Injuries in Children in Singapore.

Fingertip injuries are common in children, with varying degrees of severity. However, there is limited epidemiological information in the literature. An understanding of the characteristics of these injuries can be used as a basis to prevent such injuries. Epidemiological data was gathered through a retrospective review of all fingertip injuries affecting children, that presented to our department. There were 202 children with 234 injured fingertips in a period of 36 months. Most children were boys and most children injured their left hand. The mode age affected was 2 years. Accidental crush injuries in doors was the most common cause of fingertip injuries in children. An unexpectedly high number of children have fingertip injuries, with many requiring surgical treatment. Safety awareness and prevention of door crush injuries could reduce a large number of fingertip injuries in young children.

Bone Marrow Derived Mesenchymal Stem Cell Augmentation of Rabbit Flexor Tendon Healing.

BACKGROUND: This study investigated the effect of mesenchymal stem cell implantation on flexor tendon healing using a rabbit model of flexor tendon repair. Specifically, we compared the difference between autologous and allogeneic stem cells. The influence of cell number on the outcome of flexor tendon healing was also investigated. METHODS: Repaired tendons on the rear paws of rabbits were randomly assigned into four groups: control group, 1 million autologous cells, 1 million allogeneic cells, and 4 million allogeneic cells. Rabbits were sacrificed at 3 or 8 weeks after surgery. RESULTS: Implantation of 4 million stem cells resulted in a significant increase in range of motion compared with control group at three weeks after surgery. The positive staining of collagen I in healing tendons was enhanced in stem cell treated groups three weeks after surgery. However, stem cells did not improve biomechanical properties of flexor tendons. CONCLUSIONS: High dose stem cells attenuated adhesions in the early time point following flexor tendon repair. Further work is needed determine the value of stem cell therapy in flexor tendon healing in humans.

Effect of negative-pressure wound therapy on open fractures of the lower limb.

INTRODUCTION: Early debridement and coverage has long been regarded as the standard of care for open fractures of the lower limb, as infection is a serious complication. However, the best time for wound closure remains controversial. Negative-pressure wound therapy (NPWT) is thought to result in reduced flap infection and failure. To determine the effect of NPWT, we reviewed patients with open fractures of the lower limb and compared the rates of infection and flap failure in two time-based cohorts. METHODS: Two cohorts of patients (periods 2003-2004 and 2008-2009) with Gustilo type IIIB open tibial fractures were recruited and their outcomes were compared. In the 2003-2004 cohort, wounds were dressed with occlusive dressing. In the 2008-2009 cohort, all patients underwent NPWT. Data was retrospectively analysed with regard to infection, failure, age, type of flap, comorbidities and defect size. The incidences of infection and flap failure were further analysed for any statistical difference between the different treatment protocols. RESULTS: In the 2003-2004 cohort, 33% of patients developed infection and 11% had flap failure. However, in the 2008-2009 cohort, 10% of patients developed infection and 6% had flap failure. The difference in the incidence of infection was statistically significant between the two cohorts (p = 0.029). CONCLUSION: Patients in the 2008-2009 cohort had better outcomes, and we are of the opinion that performing NPWT may have contributed to this result.

Causes and assessment of subacute and chronic wrist pain.

Wrist pain is a common presentation to the general practitioner and emergency department. Most cases are simple to treat, and pain frequently resolves with conservative treatment. However, there are certain conditions, such as scaphoid nonunion and Kienböck's disease, where delayed diagnosis and treatment can result in long-term deformity or disability. This article covers the various causes of wrist pain, recommendations on how wrist pain should be assessed, as well as details some of the common conditions that warrant specialist referral.

General practitioners' knowledge of hand surgery in Singapore: a survey study.

INTRODUCTION: Hand surgery is a subspecialty with a dedicated training programme in Singapore. Currently, Singapore is one of two countries in the world that still provides dedicated advanced hand specialty training. As hand surgeons depend on referrals from institutions and general practitioners, appropriate hand surgical referral requires the referring physician to have knowledge and understanding of common hand conditions as well as less common but more urgent surgical conditions, and their available surgical treatments. This study aimed to determine the knowledge of hand surgery and hand surgical conditions among general practitioners. METHODS: A questionnaire survey was conducted during a continuing medical education symposium on hand surgery in Singapore. Participants responded to 12 questions on hand trauma by keying the answers into a computer database system. The results were then analysed. RESULTS: A total of 35 general practitioners responded to our survey, and they were able to answer 53% of the questions correctly. We found knowledge gaps among the participants regarding hand surgical conditions, and identified areas where increased education during medical school, postgraduate training and continuing medical education may be beneficial. Areas that were found to be weak included recognising injuries that pose a high risk for developing wound infection, complications of topical steroid injection in trigger finger treatment and hand tumours. CONCLUSION: Improving hand surgery knowledge among general practitioners not only leads to improved primary care, but it can also facilitate prompt recognition of surgical problems and subsequent referral to appropriate hand surgeons for treatment. This may possibly reduce the load of tertiary institutions in treating non-urgent hand conditions.

Atypical Essex-Lopresti injury of the forearm: a case report.

The Essex-Lopresti injury of the forearm is difficult to diagnose. A missed diagnosis can lead to persistent pain and instability of the wrist. We report a 33-year-old man with a pre-existing cubital varus deformity who sustained an atypical Essex-Lopresti injury after a fall on his elbow. Accurate diagnosis requires understanding of force transmission and anatomy of the radius and ulna, as well as the proximal and distal radioulnar joints as a unit.

Prevalence of carpal fracture in Singapore.

PURPOSE: To determine the prevalence of carpal fracture in Singapore, to compare demographic differences between isolated scaphoid and other carpal fractures, and to identify parameters associated with multiple carpal fractures. METHODS: A total of 149 patients with 162 carpal fractures seen at the National University Hospital in 2009 were enrolled into the study. We retrospectively reviewed their case records and radiographic studies. Pertinent demographic data including patient age, gender, occupation, injured wrist, dominant hand, mechanism of injury, and type of carpal fracture were then recorded and statistically analyzed. We also performed a separate analysis of isolated scaphoid versus other carpal fractures and single versus multiple carpal fractures. RESULTS: Patients with carpal fracture were predominantly male (132), below 40 years of age (116), and usually right hand dominant (136). The more common occupations were students (30), full-time military national servicemen (24), and construction workers (14). Most presented after a fall on an outstretched hand from standing height (81). The scaphoid was the most common single carpal fracture (99). This was followed by triquetrum (27), hamate (5), pisiform (4), lunate (2), capitate (1), and trapezium (1). No fracture of the trapezoid was encountered. Ten patients had multiple carpal fractures, of which 4 were perilunate fracture dislocations. The mean age and male/female ratio for isolated scaphoid and other carpal fractures was 26 years versus 41 years (p<.001) and 13:1 versus 4:1 (p=.036), respectively. A high-energy mechanism of injury was the only parameter associated with multiple carpal fractures (p=.009). CONCLUSIONS: The prevalence of carpal fracture in our population was consistent with studies performed in other countries. Military conscription was identified as an at-risk activity predisposing to carpal fracture. Isolated scaphoid and other carpal fractures exhibit different demographics in terms of age and gender, which may be related to differences in the mechanism of injury. A high-energy mechanism of injury was associated with multiple carpal fractures.