Pediatric Lower Limb Lengthening Using the PRECICE Nail: Our Experience With 50 Cases.

BACKGROUND: Limb lengthening using intramedullary externally controlled motorized devices is becoming increasingly popular. There is limited literature regarding their use in the pediatric and adolescent population. This study reviews outcomes on 50 consecutive cases of intramedullary lower limb lengthening surgery in this population. METHODS: A retrospective review of all pediatric and adolescent patients treated in our institution by intramedullary lengthening for lower limb length discrepancy using the PRECICE and STRYDE intramedullary lengthening nails between 2013 and 2019. All patients were operated by a single surgeon. Data were prospectively recorded. We report on nail accuracy and reliability, consolidation index, time to full weight-bearing from completion of lengthening, joint range of movement, ASAMI bone and functional scores, presence of problems, obstacles and complications, and patient reported outcome measures (PROMS). RESULTS: Fifty cases (43 femoral and 7 tibial nails) were performed in 42 patients (20 males, 48% and 22 females, 52%). Six patients had bilateral lengthening and 2 patients had sequential lengthening. There were 28 antegrade femoral, 13 retrograde femoral and 5 tibia PRECICE nails, 2 tibial and 2 femoral PRECICE STRYDE nails. Mean age at surgery was 15 years old (12 to 17). Mean preoperative length discrepancy was 49 mm (20 to 90). Mean achieved lengthening was 46.5 mm (20 to 80). Mean percentage lengthening was 12.6% (5% to 25%). Nail accuracy was 96% and reliability 90%. Average distraction rate was 0.92 mm/d for femur and 0.64 mm/d for tibias. Consolidation index was 28 d/cm (18 to 43) and 39 d/cm (20 to 47), respectively. Time from completion of lengthening to independent full weight-bearing as observed in clinic was 45 days (21 to 70) and 34.2 days (23 to 50), respectively. ASAMI bone and functional scores were favorable and PROMS demonstrated high patient satisfaction levels. No significant complications were observed. CONCLUSIONS: We have demonstrated excellent clinical results and high patient satisfaction with intramedullary lengthening in a pediatric/adolescent population. We highly recommend thorough preoperative preparation, patient education, and a multidisciplinary approach. LEVEL OF EVIDENCE: Level IV.

Locking plate femur fracture repair in a juvenile Western chimpanzee (Pan troglodytes verus) in Sierra Leone.

This case reports the successful management of a traumatic diaphyseal femoral fracture in an infant Western chimpanzee (Pan troglodytes verus) from a rescue centre in Sierra Leone using a 2.4-mm intramedullary pin and two 2.7-mm String of Pearls™ locking plates. Locking plate use has not been previously described in chimpanzees.

Pediatric Femoral Shaft Fractures: A Multicenter Review of the AAOS Clinical Practice Guidelines Before and After 2009.

BACKGROUND: To determine if the AAOS clinical practice guidelines (CPG) for the treatment of pediatric femoral shaft fractures (2009) changed treatment, we analyzed pediatric femoral shaft fractures at 4 high-volume, geographically separated, level-1 pediatric trauma centers over a 10-year period (2004 to 2013). METHODS: Consecutive series of pediatric femoral shaft fractures (ages, birth to 18 y) treated at the 4 centers were reviewed. Treatment methods were analyzed by age and treatment method for each center and in aggregate. RESULTS: Of 2646 fractures, 1476 (55.8%) were treated nonoperatively and 1170 fractures operatively. Of the operative group, flexible intramedullary nails (IMN) were used for 568 patients (21.5%), locked intramedullary nails (LIMNs) for 309 (11.7%), and plating for 188 (7.1%). In total, 105 fractures were treated with external fixation or skeletal traction. Analysis before and after the CPG publication revealed a significant increase in the use of interlocked IMNs in patients younger than 11 years (0.5% before, 3.8% after; P<0.001). Over the same time period there was an increase in surgical management, regardless of technique, for patients younger than 5 years (6.4% before, 8.4% after; P=0.206). There were considerable differences in treatment among centers: 74% of fractures treated with plating were from a single center (center A), which also contributed 68% of patients younger than 5 years treated with plating; center B had the highest rate (41%) of flexible IMN in children younger than 5 years; center C had the highest rate (63%) of LIMN in children younger than 11 years; and center D treated the fewest patients outside the CPG guidelines. CONCLUSIONS: Following publication of the AAOS CPG, there was a significant increase in the use of LIMNs in patients younger than 11 years old and a trend toward surgical treatment in patients younger than 5 years. The considerable variability among centers in treatment methods and adherence to the CPG highlights the need for further outcome studies to better define optimal treatment methods and perhaps update the AAOS CPG guidelines. LEVEL OF EVIDENCE: Level III-therapeutic.

Treatment of Unstable Pediatric Tibial Shaft Fractures with Titanium Elastic Nails.

Background and objectives: Pediatric tibial shaft fractures often have satisfactory outcomes after closed reduction and casting. However, surgical treatment may be required in unstable or open fractures. Titanium elastic nails (TENs) are a good option for the surgical treatment of pediatric tibial fractures due to their advantages such as short hospitalization periods, easy applicability, early weight bearing, and early union. In this study, we evaluated radiological and functional outcomes in pediatric patients with tibial shaft fractures that underwent fixation with TENs. Materials and methods: A total of twenty tibial shaft fractures that were treated with TENs in our clinic between 2013 and 2017 were retrospectively reviewed. The mean age at injury was 8.9 ± 2.78 (range of 3-14) years. Seven (35%) out of 20 fractures were open fractures, of which one fracture was classified as Grade I and six fractures were classified as Grade II. In each patient, antegrade nailing was performed by inserting a TEN in the medial and another TEN in the lateral side of the proximal metaphysis. Clinical outcomes including union, alignment, leg-length inequality, and complications were evaluated using modified Flynn's criteria. Results: The mean time to union was 10.85 ± 3.39 (range of 6-20) weeks. No patient had a sagittal or coronal angulation of over 10°. One patient had a leg-length inequality of 10 mm. Among three patients with open fractures, two of them had superficial wound infections and the other patient had a deep wound infection. All the infections were successfully treated with appropriate antibiotic therapies. Four other patients had pin tract irritation that required no intervention. No significant difference was observed between patients with open and closed fractures with regard to the clinical and radiological findings although patients with open fractures had a significantly higher complication rate compared to patients with closed fractures (p < 0.05). No patient had a restricted range of motion of the ankle and knee joints. Twelve (60%) patients had an excellent outcome, and eight (40%) patients had a satisfactory outcome. Conclusions: Intramedullary fixation with TENs provides favorable outcomes and reduced complication rates in the treatment of unstable pediatric tibial shaft fractures that cannot be reduced with conservative treatment modalities or cannot be casted due to the presence of an edema or open wound.

Epidemiology, treatment and mortality of trochanteric and subtrochanteric hip fractures: data from the Swedish fracture register.

BACKGROUND: Hip fractures are a major worldwide public health problem and includes two main types of fractures: the intracapsular (cervical) and the extracapsular (trochanteric and subtrochanteric) fractures. The aim of this study on patients with trochanteric and subtrochanteric hip fractures was to describe the epidemiology, treatment and outcome in terms of mortality within the context of a large register study. METHODS: A descriptive epidemiological register study including patients registered in the national Swedish Fracture Register from January 2014 to December 2016. Inclusion criteria were all primary surgically treated traumatic non-pathological trochanteric and subtrochanteric femoral fractures in patients aged 18 years and above. Individual patient data (age, gender, injury location, injury cause, fracture type, treatment and timing of surgery) were retrieved from the register database. Mortality data was obtained via linkage to the Swedish Death Register. RESULTS: A total of 10,548 consecutive patients were identified and included in the study. The mean (±SD) age for all patients was 82 ± 11 years and the majority of the patients were females (69%). Most of the fractures were caused by a fall at the same level (83%) at the patients' accommodation (75%). Fractures were classified using the AO/OTA classification as 31-A1 in 29%, as 31-A2 in 49% and as 31-A3 in 22% of the cases. The most commonly used implant was a short antegrade intramedullary nail (42%), followed by a plate with sliding hip screw (37%). With increasing fracture complexity, the proportion of intramedullary nails was increasing, and also the use of long versus short nails. The majority of the patients were operated within 36 h (90%). There was a higher mortality at 30 days and 1 year for males, and for all those who were delayed to surgery > 36 h. CONCLUSION: Safety measures to prevent fall at elderly patient's accommodation might be a way to reduce the number of trochanteric and subtrochanteric hip fractures. Surgery as soon as possible without delay should be considered to reduce the mortality rate. The selection of surgical methods depends on the fracture complexity.

A review of atypical subtrochanteric femoral fractures in Northern Ireland between 2010 and 2014.

The term atypical femoral fractures most commonly occur in the subtrochanteric area. Concerns exist regarding the role of bisphosphonate treatment in their aetiology. Which surgical intervention provides the best outcome remains contentious. We reviewed all atypical subtrochanteric femoral fractures treated in Northern Ireland over 5 years, specifically investigating incidence, prodromal symptoms, association with bisphosphonates and optimal fixation methods. All subtrochanteric fractures treated in the region were identified and reviewed for atypical features. Case notes and imaging were then reviewed for each patient. A total of 364 subtrochanteric femoral fractures were identified during the 5-year study period. Twenty-six of these met the criteria for an atypical fracture (7%). Thirteen patients (50%) had presented with prodromal symptoms prior to complete fracture, six of which had radiological evidence of an incomplete fracture of the lateral cortex. Thirteen patients had a history of bisphosphonate treatment. All were treated operatively, with twenty-five cephalomedullary nails and one dynamic hip screw. Twenty-one patients had follow-up for greater than 2 months, nine of which (42.9%) achieved radiological union with a mean time to union of 297 days. Dynamically locked nails had a higher union rate than statically locked (80% versus 33.3%). Four patients required major revision surgery (15.4%). The quality of reduction was statistically significant in predicting need for revision. Atypical fractures often present with prodromal symptoms. Complete fractures are difficult to successfully manage with longer than expected times to union. Treatment with a dynamically locked, cephalomedullary with a good reduction provided the best results.

Comparison of the effect of different infusion rates of sufentanil on surgical stress index during cranial pinning in children under general anaesthesia: a randomized controlled study.

BACKGROUND: Surgical stress index (SSI) is an established indicator for intraoperative nociception. Opioids are used to block stimulus of cranial pinning in neurosurgery. We investigated the effect of different infusion rates of sufentanil on SSI during cranial pinning in children under general anaesthesia. METHODS: Forty-nine children (2-12 years of age) underwent neurosurgery with pinning. The children were randomized into three groups based on the rate of sufentanil infusion: 0.2, 0.5, and 0.8 µg·kg-1·hr.-1. Continuous sufentanil infusion began following neuromuscular blockade administration, at a rate determined by each patient's assigned treatment group. Following preparation for surgery, cranial pinning was performed. Systolic, diastolic, and mean blood pressures, along with heart rate and photoplethysmographic data, were continuously recorded from 1 min prior to cranial pinning through 5 min after cranial pinning, in 1-min intervals. SSI was calculated following the completion of surgery. Differences in measured outcomes over time among the three groups were evaluated using a generalized estimation equation. Differences in pinning outcomes in the same group were evaluated with Freidman test. RESULTS: We found no statistical differences in long-term SSI that were associated with different infusion rates of sufentanil during cranial pinning. Blood pressures in all groups increased for 2 min after cranial pinning, and then decreased; we found no statistical difference in long-term blood pressure values among the groups. Heart rate increased after pinning in the group that received a low-dose infusion of sufentanil. CONCLUSIONS: Since SSI was intended to measure the blunting effects of sufentanil towards the noxious stimulus of cranial pinning, our results suggest that SSI might not be sufficiently sensitive to monitor the nociceptive response in children. TRIAL REGISTRATION: ( KCT0000978 , Jan-07, 2014).

Ultrasonography-guided reduction of pediatric radial neck fractures.

BACKGROUND: Treatment of displaced and angulated radial neck fractures in children is controversial and challenging. Numerous studies have been conducted regarding treatment algorithms and surgical techniques that use fluoroscopy. However, ultrasonography (US)-guided reduction of pediatric radial neck fractures has not been reported yet. We aimed to determine the safety and efficacy of US-guided reduction and fixation of radial neck fractures in children. METHODS: Among 28 cases of radial neck fracture from 2014 to 2016, 12 were classified as type III or IV according to the Judet classification. All 12 patients underwent US-guided reduction and percutaneous fixation with Kirschner wire and follow-up for more than 6 months. US was used primarily to monitor the angulation and reduction of the radial neck. Fluoroscopy was applied to confirm the fixation with Kirschner wire. Dose area product (DAP; mGy/cm2) was measured to assess per-procedure radiation dose. Radiological and clinical results were evaluated at 6 months after the surgery by using the Metaizeau criteria. RESULTS: Of the patients, 4 were boys and 8 were girls, with a mean age of 7.7 years (range, 5-11 years). Judet type III fractures accounted for 83% of all injuries. The mean preoperative radial angulation was 62.5° (range: 46°-76°). The mean postoperative radial angulation was 5.6° (range: 2°-9°). The mean fluoroscopy time was 31 s (range: 10-73 s), and the mean DAP was 10.7 mGy/cm2 (range: 7.2-18.7 mGy/cm2). The mean follow-up period was 18.3 months (range, 8-24 months). According to the Metaizeau criteria, 10 cases were excellent and 2 cases were good at the last follow-up. CONCLUSIONS: US-guided reduction and percutaneous fixation is safe and reliable option to treat displaced radial neck fractures in children.

National Surgical Trends for Distal Radius Fractures in Korea.

The objective of this study was to investigate national surgical trends for distal radius fractures (DRFs) in Korea and analyze healthcare institution type-specific surgical trends. We analyzed a nationwide database acquired from the Korean Health Insurance Review and Assessment Service (HIRA) from 2011 to 2015. International Classification of Diseases, 10th revision (ICD-10) codes and procedure codes were used to identify patients aged ≥ 20 years with newly diagnosed DRFs. A total of 459,388 DRFs occurred from 2011 to 2015. The proportion of DRF cases treated by surgery tended to increase over time, from 32.6% in 2011 to 38.3% in 2015 (P < 0.001). Open reduction with internal fixation (ORIF) using a plate steadily gained in popularity each year, increasing from 39.2% of overall surgeries in 2011 to 60.9% in 2015. The type of surgery for DRFs differed depending on the type of healthcare institution. ORIF (91%) was the most popular procedure in tertiary hospitals, whereas percutaneous pinning (58%) was most popular in clinics. In addition, general hospitals and hospitals with 30-100 beds used external fixation more frequently than tertiary hospitals and clinics did. Overall, our findings indicate that surgical treatment of DRF, particularly ORIF, continues to increase, and that the component ratio of operation codes differed according to the healthcare institution type.

Treatment of wrist fractures 2009-14. / Behandling av håndleddsbrudd 2009 ­ 14.

BACKGROUND: The purpose of the study was to conduct a systematic analysis based on data from the Norwegian Patient Registry and describe the incidence and treatment of wrist fractures among adults, at national level and in the catchment areas of the various regional health authorities. MATERIAL AND METHOD: A search was conducted in the Norwegian Patient Registry for all patients aged ≥ 18 years with diagnosis codes for wrist fractures in the period 2009­2014. Age, sex and type of treatment were recorded. The results are presented as rates adjusted for age and sex for the catchment areas of Norway's 21 regional health authorities. RESULTS: In the period 2009­2014, a total of 75 132 patients aged ≥ 18 years were registered as having a wrist fracture. Almost 1/3 of these patients received operative treatment. During this period, the age- and sex-adjusted rate of wrist fractures in Norway averaged 244 per 100 000 inhabitants per year. Operation rates varied across catchment areas by a factor of three, and the use of plates by a factor of nine. INTERPRETATION: We found great variation in clinical practice, which is reflected in differences in operation rates and choice of surgical method across the catchment areas to which the patients belong.

Efficacy And Safety Of Interlocked Intramedullary Nailing For Open Fracture Shaft Of Tibia.

BACKGROUND: Due to increasing population and changing human habits the number of accidents and high energy trauma is rising. Management of open fracture tibia is a complex problem and is a challenge for both orthopaedic and plastic surgeons. The study was carried out to ascertain the efficacy and safety of interlocked intra-medullary nailing for open shaft tibial fractures in patients presenting at or after 24hr of injury. METHODS: In this descriptive case series, over a period of 6 moths, 163 consecutive cases of open fracture of tibial shaft were reviewed in terms of clinical profile, time of presentation, and gender distribution. RESULTS: In this study mean age was 30±0.02 years. Males comprised 85% of study population while 15% were females. Gustilo-I type fracture and Gustilo-II type fracture was diagnosed in 90% and 10% patients respectively. Thirty three percent patients had wound infection while fracture union was found in 15% cases. Moreover interlocked intramedullary nailing for open fracture shaft of tibia was safe in 80% patients while this procedure was effective in 85%. CONCLUSIONS: Un-reamed, interlocked intra-medullary nailing may be considered as a suitable option for treatment of open fractures of tibia.

The Metacarpal Locked Intramedullary Nail: Comparative Biomechanical Evaluation of New Implant Design for Metacarpal Fractures.

BACKGROUND: The optimal fixation of metacarpal fracture should provide sufficient stability to permit early functionfor all types of fracture. However; it must preserve surrounding soft tissue during application and not require secondary removal due to its prominence. The prototype of metacarpal locked intramedullary nail (MCLN) was designed by our institute aiming to achieve those allfeatures. OBJECTIVE: To biomechanically test our newly designed, locked metacarpal nail and compare with common current available fixation methods. MATERIAL AND METHOD: Thirty chicken humeri were devided into 3 groups (n = 1 per group) according tofixation techniques: MCLN, 1.5 mm miniplate (Synthes), and Kirschner wire. After complete fixation, all specimens were osteotomized at mid-shaft creating transverse fractures. Five specimens from each group were tested by load of failure under axial compression, and another five under bending force. RESULTS: In axial compression model, the loads tofailure in MCLN group was greatest (460 ± 17 N), which was significant higher than the Kirschner wire group. The MCLN group also showed the highest load to failure in bending test (341 ± 10 N). This value reaches statistical significance when compared with plate and Kirschner wire groups. CONCLUSION: The MCLN construct provided higher stability than miniplate and Kirschner wire fixation both in axial and bending mode. Together with the minimally invasive and soft tissue-friendly design concept, this study suggests that MCLN is promising fixation option for metacarpal fracture.

In situ posterolateral and fibular interbody fusion in high grade spondylolysthesis.

OBJECTIVE: High-grade spondylolysthesis and spondyloptosis management have various options. There were no large series reported to support any particular treatment modality. The aim of surgery is to get solid bony fusion to get relief of instability and its symptoms as well as relief of neurological symptoms. There are many treatment options which are associated with technical difficulties and high incidence of complications and failures. In situ transsacral fibular graft with posterolateral fusion along with posterior decompression is a good surgical option. It offers anterior and posterolateral fusion for instability pain and relief of neurological symptoms in most of the patients. It is technically simple, with no major surgery-related complications. MATERIALS AND METHODS: The cases of high-grade spondylolysthesis operated since 2008 with one year minimal follow up were included in this study. Six cases were operated during this period. All were females in their second and third decade of life. All of them had transsacral fibular grafting with posterolateral fusion and decompression. One of the cases had additional anterior procedure with sacral widening with bone graft. The clinical status and bony fusion has been assessed at the end of one year after surgery and also for assessing final outcome. RESULTS: All the patients had solid bony fusion with no progression of slip and are pain free and relived of neurological symptoms. conclusions: In situ transsacral fibular graft with posterolateral fusion and posterior decompression is technically simple surgical option with minimal risks and reliable outcome.

Internal fixation of intertrochanteric hip fractures: a clinical comparison of two implant designs.

OBJECTIVE: To compare two internal fixation devices clinically in stabilisation of intertrochanteric femur fractures. METHODS: Eighty-seven patients were randomised upon their admission to the hospital using a sealed envelope method. Forty-five were treated with proximal femur nail antirotation (PFNA) and 42 with reverse less invasive stabilisation system (LISS). The perioperative data were recorded and compared in relation to fracture type. RESULTS: In each type of fractures, no significant differences were found with respect to the blood loss, the quality of reduction, the time to bony healing, and the Harris hip score between the 2 groups. The mean duration of surgery was significantly longer in reverse LISS group than in PFNA group. CONCLUSION: Both the PFNA and the reversed LISS are effective in the treatment of different types of intertrochanteric femur fractures. PFNA is superior to reverse LISS in terms of surgical time, weight-bearing, and perhaps fluoroscopy time.

Proximal femoral nail versus dynamic hip screw fixation for trochanteric fractures: a meta-analysis of randomized controlled trials.

BACKGROUND: The purpose of this meta-analysis was to find out whether the proximal femoral nail was better than the dynamic hip screw in the treatment of trochanteric fractures with respect to operation time, blood transfusion, hospital stay, wound complications, number of reoperation, and mortality rate. METHODS: All randomized controlled trials comparing proximal femoral nail and dynamic hip screw in the treatment of trochanteric fractures were included. Articles and conference data were extracted by two authors independently. Data was analyzed using RevMan 5.1 version. Eight trials involving 1348 fractures were retrieved. RESULTS: Compared with DHS fixation, PFN fixation had similar operation time (95% CI: -15.28-2.40, P = 0.15). Blood loss and transfusion during perioperative time were also comparable between the two fixations (95% CI: -301.39-28.11, P = 0.10; 95% CI: -356.02-107.20, P = 0.29, resp.). Outcomes of hospital stay (95% CI: -0.62-1.01, P = 0.64), wound complication (95% CI: 0.66-1.67, P = 0.82), mortality (95% CI: 0.83-1.30, P = 0.72), and reoperation (95% CI: 0.61-1.54, P = 0.90) were all similar between the two groups. CONCLUSION: PFN fixation shows the same effectiveness as DHS fixation in the parameters measured.

[Experiences with a helical femoral nail (LFN®). A multicenter study]. / Erfahrungen mit einem helikalen Femurmarknagel (LFN®). Eine multizentrische Studie.

INTRODUCTION: Antegrade intramedullary nailing is the method of choice in most femoral shaft fractures. The trochanteric entry portal of classic femoral nails is in close proximity to the piriformis tendon, the gluteus minimus tendon, the obturator tendons, and the medial femoral circumflex artery. Nail insertion lateral to the tip of the greater trochanter may be more favorable but needs the use of a helical implant. MATERIAL AND METHODS: Measurement of the reamer pathway through an entry point lateral to the superior trochanteric border was performed with a three-dimensional motion tracking sensor in human cadaveric femurs. These results provided a scientific rationale for the design of a helical femoral nail (LFN®). In a prospective multicenter study a total of 227 femoral shaft fractures were treated by nailing with the LFN. Patients were followed at 3 months (n=193) and 12 months (n=167). RESULTS: The ease of defining the entry point and inserting the nail was rated as"very good and good" by 90% of the surgeons. Intraoperative technical complications included incomplete reduction (14%), additional iatrogenic fractures (6%), and difficulties in interlocking (3.5%). At the 1-year follow-up, delayed unions were seen in 10%, secondary loss of reduction in 3%, and deep infection in 1.8% of the patients. Angular malalignment of more than 5° was seen in 5%, mostly in valgus. A normal walking capacity was seen in 68% and normal active hip flexion in 45%. CONCLUSION: The results obtained in this study during 1 year do not provide evidence for an advantage of the LFN over conventional antegrade femoral nails.

Factors affecting mortality after hip fracture surgery: a retrospective analysis of 578 patients.

PURPOSE: To determine the effect of patient and surgical factors on mortality after hip fracture surgery. DESIGN: Retrospective study. SETTING: Level-one trauma and tertiary referral centers. METHODS: Patients were eligible if they were aged 65 years or older and had undergone surgery for a non-pathological femoral neck or intertrochanteric hip fracture between 2008 and 2011. The primary outcome was mortality: within the first year after surgery, after the first year, and survival as of the last questioning date. Of the 578 eligible patients, 399 (69%) were women; mean age was 79 years; and mean follow-up was 17 months. RESULTS: Mortality during the first year was significantly more frequent in patients aged 80 years or older (67 vs. 33%; P < 0.001). Estimated overall survival was significantly longer in women (43 vs. 37%; P = 0.01). The type of fracture had no impact on mortality (P = 0.96). Patients with high ASA class had a significant effect on mortality (P < 0.001). Surgery timing did not affect mortality in univariate analysis (P = 0.25). The mortality rate for hemiarthroplasty was higher than osteosynthesis options (P = 0.03). The effect of the type of anesthesia on mortality was not significant (P = 0.74). CONCLUSIONS: Older men had the highest risk of mortality within the first year. Patients with ASA ratings of class 3 or 4 need to be evaluated carefully because they appear to be at higher risk of early mortality. Osteosynthesis has a lower mortality than does arthroplasty for hip fracture and thus should be preferred if either treatment is possible. LEVEL OF EVIDENCE: IV.

Effects of the number and the position of transfixation pins in acrylic connecting bars.

Acrylic columns are commonly used in external skeletal fixators, especially for fracture management or trans-articular fixations. To the authors' knowledge, there are no studies demonstrating if the number or position of the transfixation pins influence the ultimate strength and stiffness of the acrylic column. The objective of this study was to evaluate the effects of the number and position of transfixation pins (concentric versus eccentric) on the strength and stiffness of acrylic columns placed in axial compression. We hypothesized that strength and stiffness of acrylic columns under axial compression would not be affected by the number or position of the transfixation pins through the column. Three different groups of 12 acrylic columns were constructed with 4, 6, and 8 pins. In each group, 6 columns were constructed with the pins placed concentrically and the remaining 6 columns with the pins placed eccentrically. Each column was then placed under axial compression using a biomechanical testing machine. No significant differences were observed in ultimate strength regarding the number or position of transfixation pins (P = 0.83 and P = 0.27, respectively). However, stiffness was significantly decreased for columns with 4 eccentric pins compared with columns with 6 and 8 eccentric pins (P < 0.01) and with columns with 4 concentric pins (P < 0.001). Although the effects of transfixation pins on the rigidity of acrylic columns do not appear to be clinically significant, these tests were performed only in compression and results might differ if complete external fixator systems are used with different models of testing. Future studies are recommended.

Les colonnes d'acrylique sont couramment utilisées dans les fixateurs externes, notamment pour la gestion des fractures ou les fixations transarticulaires. Selon les auteurs, aucune étude ne démontre si le nombre ou le positionnement des broches de transfixation influence la résistance ultime et la rigidité de la colonne d'acrylique. Les objectifs de cette étude étaient d'évaluer l'effet du nombre et du positionnement des broches de transfixation (concentriques versus excentriques) sur la résistance et la rigidité des colonnes d'acryliques placées en compression axiale. Nous avons émis l'hypothèse que la résistance et la rigidité des colonnes d'acryliques en compression axiale ne seraient pas affectées par le nombre ou le positionnement des broches de transfixation à travers la colonne. Trois groupes différents de douze colonnes acryliques ont été construits avec quatre, six, et huit broches. Dans chaque groupe, six colonnes ont été construites avec les broches placées concentriquement et les six colonnes restantes avec les broches placées de manière excentrique. Chaque colonne a ensuite été placée sous compression axiale à l'aide d'une machine de tests biomécaniques. Aucune différence significative n'a été observée pour la résistance ultime selon le nombre ou le positionnement des broches de transfixation (P = 0,83 et P = 0,27, respectivement). Cependant, la rigidité a été significativement diminuée pour les colonnes avec quatre broches excentriques par rapport aux colonnes avec six et huit broches excentriques (P < 0,01) et avec les colonnes avec quatre broches concentriques (P < 0,001). Bien que les effets des broches de transfixation sur la rigidité des colonnes acryliques ne semblent pas être cliniquement significatifs, ces tests ont été effectués uniquement en compression et les résultats pourraient différer si des systèmes complets de fixateurs externes sont utilisés avec différents modèles de test. De futures études sont recommandées.(Traduit par les auteurs).

Sagittal plane alignment affects the strength of pin fixation in supracondylar humerus fractures.

ABSTRACT: Closed reduction with percutaneous pin fixation is commonly used to treat pediatric supracondylar humerus fractures. Various pin configurations of varying biomechanical strength have been described. However, to our knowledge, no biomechanical study has focused on pin alignment in the sagittal plane. Our goal was to compare the stability of fixation using 3 different pin constructs: 3 lateral pins diverging in the coronal plane but parallel in the sagittal plane (3LDP), 3 lateral pins diverging in the coronal and sagittal planes (3LDD), and 2 crossed pins (1 medial and 1 lateral).Transverse fractures were made through the olecranon fossa of 48 synthetic humeri, which were then reduced and pinned in the 3LDP, 3LDD, and crossed-pin configurations (16 specimens per group) using 1.6-mm Kirschner wires. The sagittal plane pin spread was significantly greater in the 3LDD group than in the 3LDP group, whereas we found no difference in the coronal plane. Sagittal extension testing was performed from 0° to 20° at 1°/s for 10 cycles using a mechanical torque stand. The torque required to extend the distal fragment 20° from neutral was compared between groups using one-way analysis of variance with multiple comparison post-hoc analysis. P values ≤.05 were considered significant.The 3LDD configuration was more stable than the 3LDP and crossed-pin configurations. The mean torque required to displace the pinned fractures was 5.7 Nm in the 3LDD group versus 4.1 Nm in the 3LDP group and 3.7 Nm in the crossed-pin group (both, P < .01). We found no difference in stability between the 3LDP and crossed-pin groups (P = .45).In a synthetic biomechanical model of supracondylar humerus fracture, sagittal alignment influenced pin construct stability, and greater pin spread in the sagittal plane increased construct stability when using 3 lateral pins. The lateral pin configurations were superior in stability to the crossed-pin configuration.Level of Evidence: Level V.