Biomechanical Assessment of Torsional Stiffness in a Supracondylar Humerus Fracture Model.

BACKGROUND: We assessed the effect on the torsional stability by different pin diameters and varied pin configurations in a biomechanical supracondylar humerus fracture model. METHODS: After scanning a model of a pediatric humerus, the image was imported into software. Variable pin trajectories were planned. Acrylonitrile butadiene styrene plastic models were 3-dimensionally printed with predetermined pin trajectories. Models were osteotomized and potted with a polyurethane resin. Five-pin configurations were designed to test coronal and sagittal patterns of pin placement. Each included 3 lateral pins and a medial pin. Pin diameters of 1.6, 2.0, and 2.4 mm were tested in all configurations. Three models for each pin diameter/configuration were tested to ensure uniformity. Stability of the construct was tested to determine the torque needed to deflect the osteotomy 10 degrees in internal/external rotation. Each model was tested 3 times. RESULTS: In all models/configurations, the 2.4 mm pin diameter was statistically stiffer than 1.6 mm diameter pins; this lost statistical significance in certain patterns when comparing 2.0- and 2.4-mm pins. When comparing a divergent to a parallel configuration in the coronal plane, there was no significant difference in stability when pin diameter or number were controlled. The convergent pin configuration was, in general, the least stable pattern. Use of a medial pin conferred statistically significant stiffness throughout most models as demonstrated with pin deletion. Use of 2 pins was significantly less stiff than most 3-pin models. CONCLUSIONS: Larger pin diameters confer greater stiffness among all patterns. The use of 3 lateral and 1 medial pin was not statistically different than 2 lateral and 1 medial pin in our models. Both patterns were stiffer than 3 lateral pins only or other fewer pin constructs. The alignment of pins in the sagittal plane did not affect overall construct stiffness.

Implant options for the treatment of intertrochanteric fractures of the hip: rationale, evidence, and recommendations.

AIMS: The aim of this paper is to review the evidence relating to the anatomy of the proximal femur, the geometry of the fracture and the characteristics of implants and methods of fixation of intertrochanteric fractures of the hip. MATERIALS AND METHODS: Relevant papers were identified from appropriate clinical databases and a narrative review was undertaken. RESULTS: Stable, unstable, and subtrochanteric intertrochanteric fractures vary widely in their anatomical and biomechanical characteristics, as do the implants used for their fixation. The optimal choice of implant addresses the stability of the fracture and affects the outcome. CONCLUSION: The treatment of intertrochanteric fractures of the hip has evolved along with changes in the design of the implants used to fix them, but there remains conflicting evidence to guide the choice of implant. We advocate fixation of 31A1 fractures with a sliding hip screw and all others with an intramedullary device. Cite this article: Bone Joint J 2017;99-B:128-33.

Intramedullary Nailing System in Unstable Both Bone Diaphyseal Fractures in Children.

Background Forearm fractures in pediatric population is usually managed conservatively. Unstable fractures need operative intervention like closed or open intramedullary nailing or open reduction and internal fixation with plates and screws. However, there is no consensus regarding the method of treatment according to age group. Objective To standardize the use of elastic nailing system as effective form of treatment in terms of function, cost and lower complications as compared to widely used titanium nails in developed countries.Method Sixty eight pediatric patients with both bone forearm diaphyseal fractures were managed with closed reduction and intramedullary fixation with rush nail or k-wire and followed at least for 6 months for evaluation of radiological and functional outcome. Result Patients were divided into two age groups, Group A for age of 5 to 9 years (26 patients) and Group B for age of 10-15 years (42 patients). The mean time for union for Group A patient was 7.31 weeks which was significantly lower than that of Group B patients of 9.33 weeks (p-value < 0.05). All the patients in Group A had excellent outcome and 36 (85.7%) patients had excellent outcome and 6 (14.3%) had good outcome in Group B. 5 out of 68 cases (7.35 %) had minor complications (2 in Group A and 3 in Group B). The mean time for implant removal was 17.9 weeks in Group A and 22.9 in Group B. Conclusion Intramedullary fixation for unstable diaphyseal both bone fractures of forearm is safe and cost effective method of treatment with good to excellent functional outcome with union time being significantly lower in younger age group.

The SIGN Nail: Factors in a Successful Device for Low-Resource Settings.

Surgeons in low-resource settings manage an increasing number of patients presenting with high-energy fractures. The number of surgeons and the operating time available are frequently not adequate to treat these fractures in a timely manner. A common cause of delay in treating fractures is waiting for the patient to accumulate sufficient funding to pay for the surgery, including the surgical implant. The donation of the SIGN intramedullary nail interlocking screw system obviates a major delay in timing of surgery. The SIGN intramedullary nail has been designed to be used in low-resource settings as it can be placed without fluoroscopy or electricity. The SIGN-trained surgeons are very skillful in hand reaming the canal, placing the nail, and interlocking screws without fluoroscopy. As more is learned about fracture healing, the SIGN system continues to evolve. The SIGN system is expanding to include deformity correction and soft tissue coverage.

Economic evaluation of reamed versus unreamed intramedullary nailing in patients with closed and open tibial fractures: results from the study to prospectively evaluate reamed intramedullary nails in patients with tibial fractures (SPRINT).

INTRODUCTION: Recently, results from the large, randomized study to prospectively evaluate reamed intramedullary nails in patients with tibial fractures (SPRINT) trial suggested a benefit for reamed intramedullary nail insertion in patients with closed tibial shaft fractures largely based on cost-neutral autodynamizations and a potential advantage for unreamed intramedullary nailing in open fractures. We performed an economic evaluation to compare resource use and effectiveness of reamed and unreamed intramedullary nailing using a cost-utility analysis. METHODS: We calculated quality-adjusted life years (QALYs) for each patient from a self-administered health utility index 3 questionnaire for the first 12 months following the intramedullary nailing. A convenience sample of 235 SPRINT patients provided data on costs associated with health care resource utilization. All costs are reported in Canadian dollars for the 2008 financial year. RESULTS: We found incremental effects of -0.017 (95% confidence interval [CI] -0.021-0.058) and -0.002 (95% CI -0.060-0.062) QALYs for patients treated with reamed compared with unreamed intramedullary nails in closed and open fractures, respectively. The incremental costs for reamed compared with unreamed intramedullary nailing were $51 Canadian dollars (95% CI -$2298-$2400) in closed tibial fractures and $2546 Canadian dollars (95%CI -$1773-$6864) in open tibial fractures. Unreamed nailing dominated reamed nailing for both closed and open tibial fractures; however, the cost and the utility results had high variability. CONCLUSION: Our economic analysis from a governmental perspective suggests small differences in both cost and effectiveness with large uncertainty between reamed and unreamed intramedullary nailing.

Expandable nailing system for tibial shaft fractures.

OBJECTIVE: To evaluate and present our current clinical experience in the treatment of closed and open tibial shaft fractures using the expandable intramedullary nailing system. DESIGN: Prospective study. SETTING: One level-1 trauma centre. PARTICIPANTS: Twenty-six patients with acute tibial shaft fractures with at least 10 cm of intact cortex on both sides of the fracture. INTERVENTION: Internal fixation using the Fixion expandable intramedullary nail (Disc-O-Tech Medical Technologies Ltd., Herzliya, Israel). MAIN OUTCOME MEASUREMENTS: Operative and fluoroscopy time, healing time and perioperative complications were recorded. RESULTS: Twenty-six tibial fractures were treated (OTA classification: 3 type A1, 8 A2, 8 A3, 3 B1, 3 B2, and 1 B3), six of which were open. All fractures healed by week 18.5 with an mean of 12.8+/-3.8 weeks. The operating time ranged from 20 to 50 min with an mean of 40+/-12.17 min. The fluoroscopy time ranged from 6 to 22s with a mean of 10+/-5s. In one case the nail failed to expand, as detected by X-ray control, and had to be exchanged intraoperatively. Two patients reported anterior knee pain during the follow up, but did not wish any further treatment. In a low demanding patient rotational malalignment was noted and no further action needed. CONCLUSION: According to the results of this study, the use of the Fixion nailing system, where indicated, is associated with minimal complications and very good functional outcomes in fractures OTA types A and B. The advantages of the expandable nail include the decrease in the operating and fluoroscopy time and the simplicity of its application.

[Clinical outcome and assessment of spontaneous remodeling of slipping angle in SCFE]. / Wyniki leczenia i ocena samoistnej przebudowy kata zluszczenia w mlodzienczym zluszczeniu glowy kosci udowej.

38 patients, and 45 hips has undergone treatment for slipped capital femoral epiphysis between 1995 and 2000. On the basis of the measurement of the head shaft angle on X-ray examination done preoperatively, hips were classified to one of the three groups--mild, moderate, and severe slippage. All patients had undergone pinning in situ as a primary treatment. All were checked out periodically, clinically and radiologically. On the last X-ray before physeal plate closure the head shaft angle was evaluated again. Retrospectively the head neck angle was measured as well. After the average 2.5 years long observation there was stated, that according to Southwick clinical and radiological classification 73% of good and very good outcomes were among moderate and severe slippages. On X-ray assessment 38% of initial and final projection were estimated to be comparable. Amount was inversely proportional to escalation of the slippage. On the comparable projections remodeling of the proximal femur occurred in 27% of the head-shaft angle cases, and 39% on the head-neck angle cases. Remodeling often concerned younger patients and greater slippages. Primary in situ stabilization in treatment SCFE is a correct therapy. Because of spontaneous remodeling occurring in a large amount of hips after stabilization making, a decision of realignment procedures should be rescheduled until remodeling is over after physeal plate closure. Conventional X-rays examination is a method of qualitative, not quantitative monitoring of a treatment of SCFE.

Long-term results of intramedullary pinning of forearm fractures in a developing country.

BACKGROUND: Patients with fractured forearms who were treated with intramedullary Rush pins/nails at Port Moresby General Hospital (Papua New Guinea) were studied. METHODS: Sixteen patients were reviewed 24 months after insertion of the pins/nails. RESULTS: The results indicate that good outcomes could be achieved by the use of intramedullary pins in developing countries. There were no major specific short- or long-term complications (re-fracture or non-union). Disability in terms of pain and stiffness was noted in only three out of six patients with pins in situ. These were considered temporary disabilities. CONCLUSIONS: The pins are much cheaper than plates and screws, require minimal expertise for insertion, and removal was performed under local anesthetic as outpatient cases. They remain a valuable method for managing patients with forearm fractures in developing countries.

[Damage assessment of a stainless steel lock pin]. / Schadensanalyse eines Verriegelungsnagels aus hochlegiertem Stahl.

Metallurgical investigation methods were used to determine the cause of failure in a broken and explanted lock pin. Material analysis revealed that the implant material consists of a stainless steel. The fractographic investigation indicated a fatigue fracture with its typical characteristics. Macroscopic damage of the outer surface of the implant caused the fatigue fracture in the bone fracture region. Once the lock pin had failed, further crack propagation of the fatigue fracture was largely dependent on stress intensity and/or overloading of the implant in the bone fracture region as well as on the number of stress cycles. The following items should be observed by the physician applying implant materials: 1. A material showing only very small surface scratches in the order of magnitude of thousands of millimeters should not be implanted at all, because even the smallest surface roughness may cause fractures of the material. 2. Implant materials from low-cost manufacturers should never be applied. Such materials often show construction faults (in the present case an unnecessary weld in the upper part of the lock pin) or the material itself is not well conditioned (in the present case an insufficient annealing treatment).