Comparison of five percutaneous pinning methods for unstable extra-articular distal radius fractures: A mechanical study using sawbones.

OBJECTIVES: This study aims to mechanically compare five different extra-focal bi-cortical pin configurations (using two and three pins) employed for fixation of a simulated unstable extra-articular distal radius fracture with dorsal comminution using a sawbone model. MATERIALS AND METHODS: This in vitro mechanical study was conducted between June 2019 and July 2019. A standard fracture model (Arbeitsgemeinschaft für Osteosynthesefragen [AO] type 23-A3.3) was created using a fourth generation composite artificial radius bone. Five groups with two- and three-pin configurations were tested under axial, volar, and dorsal loading with a universal test device. Mean stiffness values were compared statistically. RESULTS: Comparison of stiffness values from axial and volar loading tests between groups in paired comparison showed no statistically significant difference (p=0.194 and p=0.086, respectively). Dorsal loading tests showed statistically significant difference between the groups in pairwise comparison (p=0.002). Three-pin groups (Groups 3, 4, and 5) had higher stiffness values compared to two-pin groups (Groups 1 and 2) in dorsal loading tests (p=0.001). Three-pin configuration test groups with two divergent or convergent pins from the radial styloid performed better compared to both two-pin groups (p=0.01, p=0.002) in dorsal loading tests. CONCLUSION: Our data demonstrated that the three-pin configuration with two divergent or convergent Kirschner wires from the styloid and a third wire from the dorsal/ulnar cortex had higher stiffness values compared to two-pin configurations in dorsal loading tests. When indicated, we suggest the use of a three-pin construct. Particularly in cases with a risk of volar angulation, we recommend a three-pin configuration with two divergent or convergent bi-cortical Kirschner wires.

A cadaveric biomechanical study comparing the ease of femoral nail insertion: 1.0- vs 1.5-m bow designs.

INTRODUCTION: Anatomic fit of intramedullary nails was suggested by previous studies to improve significantly when the nail radius of curvature (ROC) is closer to the average femoral anatomy. However, no attempt has been made to investigate the impact of different ROC designs on the nail insertion process. Therefore, this biomechanical study quantitatively compared the ease of insertion between femoral intramedullary nails with a 1.0-m and a 1.5-m bow radius. MATERIALS AND METHODS: Long TFN-ADVANCED™ (TFNA, 1.0 m ROC) and Proximal Femoral Nail Antirotation nails (PFNA, 1.5 m ROC) were implanted pairwise into seven paired cadaver femora. All bones were reamed 1.5 mm larger than the nail diameter. Using a material testing machine, intramedullary nailing was then performed stepwise with 20-mm steps and a 10-mm/s insertion rate, and force was measured. The nail deformation caused by the insertion was assessed through 3D computer models built from pre- and post-nailing CT scans. The ease of insertion between TFNA and PFNA nails was quantified in terms of insertion force, insertion energy and nail deformation. RESULTS: There was no significant difference in the peak force generated during nailing between TFNA and PFNA nails (P = 0.731). However, the force measured at the end of insertion (P = 0.002) was significantly smaller in TFNA nails compared to PFNA nails. After implantation, TFNA nails showed significantly smaller deformation when compared to PFNA nails (P = 0.005, both ends aligned). Furthermore, less energy was required to insert TFNA nails; however, the difference was not significant (P = 0.25). CONCLUSIONS: Compared to PFNA nails, a significant decrease in insertion force and nail deformation was found at the end of insertion for TFNA nails. Results suggest that TFNA having a 1.0-m ROC is easier to insert for the set of femora used in this study compared to PFNA with a 1.5-m ROC.

Costs and Complications of Short Versus Long Cephalomedullary Nailing of OTA 31-A2 Proximal Femur Fractures in U.S. Veterans.

OBJECTIVES: In fractures without subtrochanteric extension, the indications for the use of short versus long cephalomedullary nails (CMNs) for intertrochanteric femur fractures are unclear. We hypothesized that long nails would be associated with higher costs and similar complication rates. DESIGN: Retrospective comparative study. SETTING: United States Department of Veterans Affairs Medical Centers. PARTICIPANTS: Patients receiving CMNs for OTA 31-A2 pertrochanteric fractures from 2001 to 2010. INTERVENTIONS: Short versus long cephalomedullary nailing. MAIN OUTCOME MEASUREMENTS: Costs, perioperative complications, readmissions, surgical failures, and mortality. RESULTS: We identified 262 patients with OTA 31-A2 pertrochanteric fractures (125 treated with short CMNs and 137 treated with long CMNs). The 2 cohorts had similar demographic and medical characteristics. There were no significant differences in perioperative complications, readmissions within 30 days, surgical failures within one year, or death within 30 days or one year. The average cost of hospitalization was significantly higher for the cohort treated with long nails (greater than $7000 in actual costs, and greater than $3000 when statistically adjusted for differences in postoperative lengths of stay). Multivariable analyses showed no significant differences in the rates of development of at least one complication, readmission, or death. CONCLUSIONS: In a cohort of patients with similar characteristics and fracture patterns, the use of long CMNs was associated with similar rates of complications, readmission, and reoperations, but significantly higher costs than with the use of short nails. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Intramedullary Nailing of Tibial Shaft Fractures: Size Matters.

OBJECTIVES: To determine optimal ratio of intramedullary nail diameter to tibial canal diameter that leads to reliable and timely healing in tibial shaft fractures. DESIGN: Retrospective case series. SETTING: Level I trauma center. PATIENTS: One hundred thirty-three fractures in 132 patients with tibial shaft fractures that underwent intramedullary nailing as definitive fixation were identified between June 2004 and July 2012 at our level I trauma center. Of these, 78 had serial radiographs out to 12 months that could be analyzed for radiographic healing with an average age of 37 years old (range 16-86 years). There were 52 males and 26 females. INTERVENTION: All patients underwent intramedullary nailing of the tibia with documentation of both the diameter of the nail and radiographic canal width at the isthmus to determine the nail to canal ratio. MAIN OUTCOME MEASURES: Patients were followed with serial radiographs for at least 12 months to determine time to healing as a function of nail to canal ratio. The senior author assessed healing at 3, 6, 9, and 12 months using RUST criteria. RESULTS: Patients with an intramedullary nail to canal diameter ratio of less than 0.8 or greater than 0.99 were 4.4 times more likely not to heal than patients with a ratio of between 0.8 and 0.99. CONCLUSION: The ideal intramedullary nail to tibial canal diameter ratio to optimize tibial shaft fracture healing is between 0.8 and 0.99. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Short Versus Long Intramedullary Nails in the Treatment of Pertrochanteric Hip Fractures: Incidence of Ipsilateral Fractures and Costs Associated With Each Implant.

OBJECTIVES: Both short intramedullary nails (SIMNs) and long intramedullary nails (LIMNs) are routinely used in the surgical treatment of pertrochanteric hip fractures. The purpose of this study was to assess the incidence of ipsilateral femur fractures after the surgical treatment of hip fractures and the overall costs associated with each implant. DESIGN: Retrospective cohort study. SETTING: Level I trauma center and 2 community hospitals. PATIENTS/PARTICIPANTS: A total of 609 patients with pertrochanteric hip fractures treated with an SIMN or LIMN from 2005 to 2011. INTERVENTION: Review of patient demographics and clinical outcomes over a 5-year follow-up period. MAIN OUTCOME MEASUREMENTS: Ipsilateral femur refracture rates were recorded for both groups, and a cost analysis was then performed to compare SIMNs and LIMNs while accounting for their observed refracture rates and surgical/hospital costs to determine the overall cost of each implant. RESULTS: Union rates were equivalent between groups and averaged over 97%. The incidence of ipsilateral femur fractures in both groups steadily increased with greater follow-up time to reach nearly 10% at 5 years. Although only 47% of all nails were locked distally, 15 of the 16 refractures occurred in nails that were not distally locked. Cost analysis revealed no significant difference in the use of short versus LIMNs over a 5-year period (P = 0.76). CONCLUSIONS: The incidence of ipsilateral femur refractures steadily rose with greater follow-up in both SIMN and LIMNs. Distally locking the initial fixation seems to protect against future femur fractures and may also affect the refracture location when using LIMNs. No differences in overall costs were seen at 1, 2, or 5 years between SIMNs and LIMNs. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Biomechanical comparision of femoral intramedullary nails for interfragmentary rotational stability.

OBJECTIVES: This study aims to investigate which intramedullary nail is biomechanically better for establishing interfragmentary rotational stability. MATERIALS AND METHODS: Thirty composite femurs were utilized in this study. We analyzed interfragmentary rotational arc displacements between 10 Nm external-6 Nm internal torques and 6 Nm external-6 Nm internal torques which imitate rotation torques while walking on a flat surface and descending stairs by administering 10 interlocking nails, 10 compression nails, and 10 Mehmet anti-rotation nails with tube compression. RESULTS: Maximum interfragmentary rotation arc displacement between 10 Nm external rotation and 6 Nm internal rotation torques was mean 1.64 mm in the Mehmet nail compressed by 7 Nm torque wrench. This value was lower by 309% (6.72 mm) from interlocking nail (p=0.000), 201% (5.42 mm) from compression nail compressed by 2.5 Nm torque wrench (p=0.000), and 26% (1.92 mm) from compression nail compressed by 7 Nm torque wrench (p>0.05). CONCLUSION: In axially stable transvers and short oblique femur fractures, Mehmet nail is superior to other intramedullary nails with limited movement between locking screw and hole, more interfragmentary compression without locking screw deformation, and no proximal nail migration.

Biomechanical comparison of three-point bending resistance of titanium and stainless steel locking screws in intramedullary nails.

OBJECTIVES: This study aims to investigate whether there is any significant difference in bending resistance between titanium and stainless steel locking screws of femur nails and to review deformation of locking screws which is a common problem in interlocking nailing. MATERIALS AND METHODS: In this study, a total of 60 pieces of 5 mm major diameter titanium and stainless steel locking screws were used as six groups in three different thread depth structures (high threaded, low threaded, and unthreaded). Three-point bending tests were conducted on steel screws placed inside stainless steel tube with 30 mm inner diameter, which imitated the level of lesser trochanter. We used an axial compression testing machine in order to determine the yield points that permanent deformation occurred in the locking screws. RESULTS: For low threaded locking screws, which are the most frequently used thread type for locking screws, the mean bending yield points were 1413 N on the titanium screws and this level was below 1922 N (2.8 BW) of level walking loading on femur for 70 kg person. On low threaded stainless screws, bending resistance was 2071 N, which was above the value of 1922 N. For high threaded locking screws, the mean bending yield points were 874 N on the titanium screws and 556 N on stainless screws. CONCLUSION: In comminuted femur shaft fractures (in full load bearing conditions), using stainless steel locking screws is better instead of titanium screws to avoid locking screw deformation since low threaded stainless steel screws were 46.5% more resistant to bending deformation than titanium ones. Stainless steel or titanium high threaded locking screws may only be carefully used in non-comminuted fractures.

[Orthopaedic implants. Application outside of patient care?]. / Orthopädisch-Unfallchirurgische Implantate. Verwendungsmöglichkeiten außerhalb der Patientenversorgung?

Internal fracture fixation represents a widespread concept for the treatment of fractures. As the number of implants increases, person tracking may be possible. In spring 2010 near Rostock (Germany), human remains including a stainless steel nail were found. Forensic analysis considered the parts of skeleton to belong to a man of medium height, exposed to outdoor conditions for several years to a few decades. The tibial nail was analysed and according to the product identification number possible hospitals of implant placement and transportation paths were determined and screened. Furthermore a match analysis of the database of missing individuals of the last 15 years was undertaken and a DNA match analysis identified a local individual who had been missing since winter 2003. Equipped with the actual patient's identity, out of academic interest a survey of clinical documents such as discharge letters and operative reports was performed, but was inconclusive. Although technically feasible, tracking the patient in this case based on the implant product number itself was unsuccessful. In this case report, the feasibility, validity and efficiency of this option are presented and discussed.

Intramedullary nailing of the femoral shaft: a prospective, randomized study.

We conducted a prospective, randomized study on 84 consecutive patients with 88 acute, traumatic femoral shaft fractures using 32 Grosse-Kempf nails, 29 Russell-Taylor nails, and 27 Synthes nails. Although total operative times and proximal and distal locking times were similar for the three groups, the procedure was faster with the Grosse-Kempf nail. Three proximal fractures could not be locked with the Synthes nail. At first follow-up, we found no significant difference in terms of pain, limp, range of motion, or time to union; however, we removed fewer Synthes nails to resolve patient complaints of pain. Three delayed unions were attributed to fracture distraction. We conclude that all three nails are suitable for the treatment of almost all femoral shaft fractures. A careful analysis of intraoperative technique and instrumentation indicates that all three nails can be used safely and easily once experience is gained. Clinical outcome is similar regardless of the nail chosen.

Proximal humerus nailing: a randomized clinical trial between curvilinear and straight nails.

BACKGROUND: Intramedullary nailing of displaced proximal humerus fractures is an attractive option in the elderly patient. However, in recent reports, some existing intramedullary nails have shown high rate of complications, so new designs are being developed. The objective of the present study is to report on outcomes and complications when comparing a straight to a curvilinear nail design. METHODS: We prospectively include 54 patients with Neer's 2- or 3-part proximal humerus fractures. Two were lost to follow-up, 26 were surgically treated with a new straight humeral nail (MultiLoc, Synthes) mean age 69 (range, 47-87 years), and 26 with a curvilinear nail (Polarus, Acumed) mean age 71 (range, 38-89 years). At final follow-up (average 14 months), patients underwent a clinical and radiographic evaluation. Clinical outcome was assessed with the adjusted Constant score. RESULTS: All but 1 fracture went on to radiographic union. Mean Constant score in the Polarus nail was 72.7 ± 16.0 and 83.3 ± 16.7 in the MultiLoc (P = .246). Symptoms related with rotator cuff disease were present in 19/26 patients (73%) and in 9/26 (34.6%), respectively (P = .001). The mean neck-shaft angle at final follow-up was 135° in the MultiLoc group and 130° in the Polarus group (P > .05). Reoperation rate was 42% for Polarus and 11.5% for MultiLoc. CONCLUSION: Straight intramedullary nails had a comparable union rate to an accepted curvilinear design, with a much lower incidence of complications. Rotator cuff pain and dysfunction can be minimized with the use of newer generation straight nails.

A classification of growth friendly spine implants.

BACKGROUND: Various types of spinal implants have been used with the objective of minimizing spinal deformities while maximizing the spine and thoracic growth in a growing child with a spinal deformity. PURPOSE: The aim of this study was to describe a classification system of growth friendly spinal implants to allow researchers and clinicians to have a common language and facilitate comparative studies. Growth friendly spinal implant systems fall into 3 categories based upon the forces of correction the implants exert on the spine, which are as follows: Distraction-based systems correct spinal deformities by mechanically applying a distractive force across a deformed segment with anchors at the top and bottom of the implants, which commonly attach to the spine, rib, and/or the pelvis. The present examples of distraction-based implants are spine-based or rib-based growing rods, vertical expandable titanium rib prosthesis, and remotely expandable devices. Compression-based systems correct spinal deformities with a compressive force applied to the convexity of the curve causing convex growth inhibition. This compressive force may be generated both mechanically at the time of implantation, as well as over time resulting from longitudinal growth of vertebral endplates hindered by the spinal implants. Examples of compression-based systems are vertebral staples and tethers. Guided growth systems correct spinal deformity by anchoring multiple vertebrae (usually including the apical vertebrae) to rods with mechanical forces including translation at the time of the initial implant. The majority of the anchors are not rigidly attached to the rods, thus permitting longitudinal growth over time as the anchors slide over the rods. Examples of guided growth systems include the Luque trolley and Shilla. CONCLUSIONS: Each system has its benefits and shortcomings. Knowledge of the fundamental principles upon which these systems are based may aid the clinician to choose an appropriate treatment for patients. Having a common language for these systems may aid in comparative research. Vertical expandable titanium rib prosthesis is used with humanitarian exemption. The other devices mentioned in this manuscript are not approved for growing constructs by the Food and Drug Administration and are used off-label.

A comparative biomechanical study of proximal femoral nail (InterTAN) and proximal femoral nail antirotation for intertrochanteric fractures.

PURPOSE: The purpose of this study was to compare the biomechanical strength of the cephalomedullary nail InterTAN in cases of intertrochanteric fractures with the commonly used PFNA. METHODS: Sixteen fresh specimens of the proximal femur were used as intertrochanteric fracture models and were fixed using two fixation devices: the new proximal femoral nail (InterTAN) and proximal femoral nail antirotation (PFNA). An intertrochanteric fracture was created in composite bone models. Each specimen was loaded to simulate single leg stance while stiffness, migration (cut out), compressive force across the fracture site, and distal fragment rotation were monitored. The different internal fixation methods were tested by an experimental press analysis. RESULTS: Results of tests for femoral strength, stiffness, stability, and bearing capacity demonstrated that the biomechanical function of InterTAN was better than that of PFNA (P < 0.05). Compared with the PFNA nail, InterTAN showed increased strength, stiffness, and resistance torque of 30%, 15%, and 27%, respectively. CONCLUSION: Comparison of the treatment of intertrochanteric fractures with InterTAN and PFNA internal fixation showed that the InterTAN yielded improvement relative to the PFNA. InterTAN has a firmer and biomechanically superior performance and is therefore an ideal internal fixation method for treating intertrochanteric fractures. Additional research in osteopenic bone is necessary to comprehensively characterize the effects of the design enhancements of these two implants.

How to prevent cut-out and cut-through in biaxial proximal femoral nails: is there anything beyond lag screw positioning and tip-apex distance?

PURPOSE: Hip perforation is a major complication in proximal femoral nailing. For biaxial nails, knowledge of their biomechanics is limited. Besides re-evaluation of accepted risk factors like the tip-apex distance (TAD), we analysed the influence of anti-rotational pin length. METHODS: We compared 22 hip perforation cases to 50 randomly chosen controls. TAD, lag-screw position, angle between lag-screw and femoral neck axis, lag-screw gliding capacity, displacement and anti-rotational pin length were investigated. RESULTS: Hip perforation was associated with a higher angle of deviation between lag-screw and femoral neck axis (p = 0.001), a lower telescoping capacity of the lag screw (p = 0.02), and higher TAD (p = 0.048). If the anti-rotational pin exceeded a line connecting the tip of the nail and the lag screw (NS line), hip perforation incidence was increased (p = 0.009). Inadequate pin length resulted in an odds ratio of 10.8 for hip perforation (p = 0.001). CONCLUSIONS: In biaxial nails anti-rotational element positioning is underestimated, however, crucial.

Cervicocephalic medial screw migration after intertrochanteric fracture fixation, OTA/AO 31-A2, using intramedullary nail Gamma3: report of 2 cases and literature review.

Cervicocephalic screw medialization is a rare complication after intertrochanteric fracture synthesis with a Gamma3-type intramedullary nail. Only 6 cases of intrapelvic penetration by Gamma3 lag screw have been described. We now describe 2 additional cases and a review of the literature.

Tibiotarsal fracture repair in a bald eagle (Haliaeetus leucocephalus) using an interlocking nail.

A 14-yr-old, 5.13-kg bald eagle (Haliaeetus leucocephalus) was hit by a car and presented to the Michigan State University Small Animal Clinic with an open, grade II, transverse, midshaft, Winquist-Hansen type-II-comminuted left tibiotarsal fracture. The fracture was reduced and fixation established with a 4.7-mm-diameter, 112-mm-long, four-hole veterinary intramedullary interlocking nail maintained in position by single 2-mm transcortical screws placed in the main proximal and distal fragments. The bird was weight bearing on the bandaged limb 48 hr postoperatively. Radiographs obtained 4 wk postoperatively revealed bridging callus over three of four cortices. The bird was released after 5 mo of rehabilitation.

Femoral nailing for metastatic disease of the femur: a comparison of reamed and unreamed femoral nailing.

A total of 73 consecutive intramedullary femoral nails were inserted for metastatic disease of the femur; 43 were reamed and 30 were solid nails. The two groups were similar with regards to age, type of primary tumour, anatomical site, acute or 'impending' fracture and postoperative survival. The 'solid' nail offers a satisfactory alternative form of stabilisation for metastatic disease of the femur with rates of implant failure which are comparable with the reamed nail. In this series bilateral nailing was not associated with any increase in mortality. Contrary to other reports, imposing a delay in patients with pain and a short life expectancy seems unjustified. The use of the 'solid' femoral nail does not prevent sudden death due to massive fat embolism.

Complications of the Bailey-Dubow elongating nail in osteogenesis imperfecta: 34 children with 110 nails.

The Bailey-Dubow nail, inserted in the femur or tibia of 34 children with osteogenesis imperfecta (OI), was studied retrospectively. Comparing the various groups of OI, no significant difference was found. Location of the nail (tibia or femur) did not influence the complication rate significantly. The reoperation rate was 29%, a rate comparable to that reported in earlier studies. The part of the nail located around the knee had a significantly higher migration rate (P = 0.005 at obturator ends and P = 0.007 at sleeve ends). Migration of the nail was the reason to reoperate in 50% of the patients. Better anchoring of the T-piece will substantially decrease the complication rate. In consideration of the different functional capacities of the OI population, the complications are likely related more to the hardware than to the patient.

Enclavado intramedular en fracturas cerradas de tibia fresado o no fresado / Intramedullary nailing for close fractures of the tibia: reaming versus not reaming

Cuarenta y siete pacientes con 49 fracturas cerradas de la diáfisis tibial fueron tratados quirúrgicamente mediante estabilización con clavos intramedulares en cerrojo. Veintiséis fracturas fueron tratadas con clavo de tibia sin fresado (UTN) y las restantes con fresado del canal medular. Se realizó reducción cerrada en 47 fracturas. Se logró la consolidación en promedio a las 9.8 semanas en los casos tratados con fresado del conducto medular y a las 11.04 en los casos de UTN. Ningún paciente presentó secuelas