Posterior buttress plate with locking compression plate for Hoffa fracture

BackgroundMany difficulties are associated with treating fractures of the posterior condyle of the femur (Hoffa fractures). Anatomical reduction and internal fixation are optimum for such intra-articular fractures. Some surgeons use anteroposterior screws to achieve direct stability. However, screw fixation is not adequate in some cases. To increase stability, we treat Hoffa fractures with a posterior buttress plate; we use a twisted, 1/3 tubular plate at the posterior surface and a supplementary, locking compression plate (LCP) for additional stability.MethodsPatients who had sustained Hoffa fractures between January 2006 and March 2009 were included in this study. Patients comprised three males and two females with a mean age of 73.6 years at the time of surgery. A 3.5-mm 1/3 tubular plate was twisted and applied to the posterolateral aspect of the distal femur. This was combined with an LCP on the distal femur to achieve a rafting effect.ResultsAll fractures were healed within 15 weeks. There were no instances of nonunion, infection, or implant removal. The mean range of motion was ?3° to 121°. Four patients had no pain in the treated limb and one had mild pain on weight bearing. The average Oxford Knee Score was 44.6 points. All patients achieved satisfactory joint function and regained their walking ability with good clinical results.ConclusionsImproved stability associated with this technique enables patients to begin range-of-motion training and return to their normal activities sooner; this resulted in good outcome.     

Biomechanical cadaver testing of a fixed-angle plate in comparison to tension wiring and screw fixation in transverse patella fractures

IntroductionOperative treatment of patella fractures is frequently associated with implant failure and secondary dislocation which can be attributed to the employed hardware. Therefore, a 2.7 mm fixed-angle plate designed for the treatment of patella fractures was tested biomechanically against the currently preferred methods of fixation. It was hypothesized that under simulated cyclic loading fixed-angle plating would be superior to modified anterior tension wiring or cannulated lag screws with anterior tension wiring.Materials and methodsEighteen human cadaver knees, matched by bone mineral density and age, were divided into three groups of six. After setting a transverse patella fracture each group received one of the osteosyntheses mentioned above. Repetitive testing over 100 cycles was performed at non-destructive loads by simulating knee motion from 90° flexion to full extension.ResultsAnterior tension wiring as well as lag screws with tension wiring showed significant fracture displacement after the initial cycle already. Both constructs, lag screws plus wiring (3.7 ± 2.7 mm) as well as tension wiring alone (7.1 ± 2.2 mm) displayed fracture displacement of >2 mm which is clinically regarded as failure. Those patellae stabilized with fixed-angle plates showed no significant fracture gap widening after completion of 100 cycles (0.7 ± 0.5 mm). The differences between the fixed-angle plate group and the other two groups were statistically significant (p < 0.05).ConclusionIn contrast to modified anterior tension wiring and cannulated lag screws with anterior tension wiring the bilateral fixed-angle plate was the only fixation device to stabilize transverse patella fractures securely and sustainably.     

Fixation of quadrilateral plate fractures of the acetabulum using the buttress screw: A novel technique

IntroductionQuadrilateral plate fractures constitute one of the most challenging components of acetabular fractures. The objective of this study is to describe and evaluate the novel technique of buttress screw fixation of the quadrilateral plate component of the acetabular fractures.Patients & methodsForty cases of acetabular fracture with associated quadrilateral plate component were included in the study. Mean age was 35 years (range, 16 − 68 years), with a mean follow-up 16.4 months (range, 9 − 36 months). Fixation of the quadrilateral plate was achieved by one or more buttress screws. The screws were inserted through the reconstruction plate, and placed close to the edge of the pelvic brim. To effectively achieve the 3-point fixation principle, the screw was inserted through the plate hole then outside the bone rubbing on the pelvic surface of the quadrilateral plate.ResultsAnatomical reduction of the quadrilateral plate component of the fractures was achieved in all but one patient. The modified Merle D’Aubigné and Postel score was excellent in 13 cases, good in 23 cases, fair in three cases, and poor in one case. No screw displacement or failures were observed during follow-up evaluation. No major complications related to this technique were observed in this series.ConclusionButtress screw fixation of the quadrilateral plate fracture component in associated acetabular fractures is a safe and effective technique for reduction and fixation of these challenging fractures with no major complications related to this novel technique.     

The outcome of unstable proximal femoral fracture treated with reverse LISS plates

BackgroundThe Russel-Taylor type 2B fractures compromised the trochanteric region and medial buttress of proximal femur. This fracture pattern limits the choice of implants and raises the risk of adverse outcomes. We aimed to (i) determine the outcome of Russel-Taylor type 2B fractures treated using reverse less invasive stabilization system plates (LISS-DF) and to (ii) learn what factors affected outcomes after osteosynthesis with reverse LISS plates.DesignA retrospective studySettingThe study was conducted at a Level III trauma center in Taiwan.MethodsTwenty-five consecutive patients presenting with a Russel-Taylor type 2B fracture were enrolled. All cases were treated with reverse LISS plates. A Modified Radiographic Union Scale for Femur (RUSF), Radiographic parameters, functional scores, and complications were assessed.ResultsUnion occurred in 21 cases at an average of 18.8 weeks. The average immediate postoperative neck-shaft angle was 130° (range: 122–135°) compared with 139° (range: 135–141°, p = 0.05) on the contralateral side. Two cases had complications of proximal screws cutting out and two cases had broken implants. Finally, all 4 cases required repeated surgeries (16%). Malunion occurred in 4 patients and early mechanical failure (proximal screws cut out) occurred in 2. There was a significant difference in the purchase index of the proximal screws between cases with redisplacement and those without (26.4 mm and 98.6 mm, p = 0.01).ConclusionsThe use of reverse LISS plate appeared to be an alternative procedure for the specific pattern in the present study. We recommend using this reverse locking plate to treat unstable proximal femoral fractures with meticulous techniques of placing plates. Adequate purchase of the proximal locking screws might decrease the risks of complications.     

Percutaneous screw fixation for the acetabular fracture with quadrilateral plate involved by three-dimensional fluoroscopy navigation: surgical technique

BackgroundThe percutaneous three-dimensional (3D)-fluoroscopic-navigated screw directing to the quadrilateral plate was attempted.Materials and methodsFive patients with acetabular fractures were treated by 3D navigated percutaneous screw. The quadrilateral plate was involved in all the patients. The Arcadis 3D (ARCADIS Orbic 3D^®; Siemens AG Healthcare Sector, Erlangen, Germany) and computer navigation system (stryker navigation system) were employed, screwing trajectory was attempted to anchor the quadrilateral plate perpendicularly to the fracture line and close to the joint cartilage as much as possible. Parameters including fracture gap closure (P1), distance to the joint cartilage (P2), angulations between the screw and the fracture line (P3), were measured with the software installed on the machine of Arcadis 3D.ResultSeven screws were inserted with the use of 3D fluoroscopic navigation. The quadrilateral plate was hold by percutaneous screws. The closure of fracture gap was achieved in 3 patients by 2–3 mm. The nearest distance from the screw to the joint cartilage was ranged from <1 mm to 6 mm. The angulations between the screw and the fracture line was 80–90° in three patients, it was 60° and 65° respectively on the rest two patients. All patients felt pain free 1 week after the operation. No complication was noted postoperatively.ConclusionThe surgical technique of percutaneous screwing for the acetabular fracture with three-dimensional fluoroscopy-based navigation was demonstrated.     

Orthogonal plating of intra-articular distal radius fractures with an associated radial column fracture via a single volar approach

IntroductionThe purpose of this study was to investigate the radiographic and functional outcome of orthogonal plating (two plates at right angles) via a single volar approach for fixation of intra-articular distal radius fractures with an associated radial column fracture.MethodsIn a retrospective, chart-based review, we identified 14 consecutive patients with an intra-articular distal radial fracture who had been treated with locked volar plate fixation and an additional radial column plate. Radial column plates were LCP Distal Radius Plates 2.4; volar plates were LCP Distal Radius Plates 2.4 (n = 13) or LCP T-plate (n = 1). These patients were operated on using the extended volar flexor carpi radialis (FCR) approach as described by Orbay. Radiographic measurements, healing rates, time to union, complications, range of motion, the Gartland and Werley score, and the QuickDASH questionnaire were done in order to evaluate the radiographic and functional outcomes of this technique.ResultsThirteen of the 14 fractures healed within 7 weeks after surgery. Two implant removals were done. One patient had malposition of the fracture and carpal tunnel symptoms, which required a second surgery. No other complications (e.g., first dorsal compartment problems, radial plate prominence problems and radial sensory nerve problems) were observed. The average length of follow-up was 30 months (range, 12.8 months to 5.4 years). Radiographic results after healing were radial inclination 20°, radial length 11.4 mm, tilt 6° volar, ulnar variance ?0.5 mm, articular gap 0.1 mm and step-off 0.1 mm. Wrist range of motion was flexion–extension arc 93°, ulnar–radial deviation arc 49° and pronation–supination arc 152°. Nine patients scored ‘excellent’ on the Gartland and Werley score, while the remaining five patients scored ‘good’. The average QuickDASH score was 13.4.ConclusionAdditional fixation of a radial column process in an intra-articular distal radius fracture via the extended FCR approach using a standard volar plate and radial LCP resulted in good/excellent radiographic and functional outcome.Level of evidenceTherapeutic IV.     

Dynamic hip screw with locking side plate: a viable treatment option for intertrochanteric fracture

Objective： Dynamic hip screw （DHS） is recommended for the fixation of stable intertrochanteric fractures. Its postoperative cut-out rate ranges from I% to 6%. In osteoporotic bone, normal screws in DHS blade provide less anchorage compared to locking screws. This study aims to compare DHS with locking side plate and conventional side plate. Methods： Fifty consecutive patients with intertrochanteric fractures were randomly allocated for fixation with a standard DHS （group A） and locking DHS （Combi plate, group B）. We compared the clinical and radiological outcomes for the conventional DHS and locking DHS in intertrochanteric fractures. Functional outcome was evaluated using the Parker mobility score. Results： Coxa valga was found more frequently in group A than in group B （12% vs. 0%, P=0.42）. Coxa vara showed the same trend （12% vs. 8%, P=0.81）. Rate of restoration of postoperative neck-shaft angle within 20° of sound side was higher in group B （8% cases） than in group A （4% cases, P=0.98）. The rate of anteversion angle restoration within 10° of sound side was also higher in group B （100% vs. 88%, P=0.85）. The average lag screw slippage in group A and group B was 3.2 mm and 4.2 mm, the average fracture union duration was 17.1 weeks and 16.4 weeks, and the mean Parker score was 5.6 and 5.8 respectively. Screw cut-out was seen in one patient in group A. No cut-out was seen in any of the patient in group B. No patient developed deep infection, avascular necrosis, deep vein thrombosis or any other significant complications. Conclusion： The present study demonstrated that treating intertrochanteric fracture with a locking DHS allows sound bone healing and is not associated with any major complications. Although this report is promising, it should be interpreted with caution because only a prospective study with a large sample size would allow definitive conclusion.     

Finite element analysis of the three different posterior malleolus fixation strategies in relation to different fracture sizes

PurposeAppropriate fixation method for the posterior malleolar fractures (PMF) according to the fracture size is still not clear. Aim of this study was to evaluate the outcomes of the different fixation methods used for fixation of PMF by finite element analysis (FEA) and to compare the effect of fixation constructs on the size of the fracture computationally.Materials and methodsThree dimensional model of the tibia was reconstructed from computed tomography (CT) images. PMF of 30%, 40% and 50% fragment sizes were simulated through computational processing. Two antero-posterior (AP) lag screws, two postero-anterior (PA) lag screws and posterior buttress plate were analysed for three different fracture volumes. The simulated loads of 350 N and 700 N were applied to the proximal tibial end. Models were fixed distally in all degrees of freedom.ResultsIn single limb standing condition, the posterior plate group produced the lowest relative displacement (RD) among all the groups (0.01, 0.03 and 0.06 mm). Further nodal analysis of the highest RD fracture group showed a higher mean displacement of 4.77 mm and 4.23 mm in AP and PA lag screws model (p = 0.000). The amounts of stress subjected to these implants, 134.36 MPa and 140.75 MPa were also significantly lower (p = 0.000). There was a negative correlation (p = 0.021) between implant stress and the displacement which signifies a less stable fixation using AP and PA lag screws.ConclusionProgressively increasing fracture size demands more stable fixation construct because RD increases significantly. Posterior buttress plate produces superior stability and lowest RD in PMF models irrespective of the fragment size.     

The influence of different osteosynthesis configurations with locking compression plates (LCP) on stability and fracture healing after an oblique 45° angle osteotomy

BackgroundLocking compression plates are used in various configurations with lack of detailed information on consequent bone healing.Study designIn this in vivo study in sheep 5 different applications of locking compression plate (LCP) were tested using a 45° oblique osteotomy simulating simple fracture pattern. 60 Swiss Alpine sheep where assigned to 5 different groups with 12 sheep each (Group 1: interfragmentary lag screw and an LCP fixed with standard cortex screws as neutralisation plate; Group 2: interfragmentary lag screw and LCP with locking head screws; Group 3: compression plate technique (hybrid construct); Group 4: internal fixator without fracture gap; Group 5: internal fixator with 3 mm gap at the osteotomy site). One half of each group (6 sheep) was monitored for 6 weeks, and the other half (6 sheep) where followed for 12 weeks.MethodsX-rays at 3, 6, 9 and 12 weeks were performed to monitor the healing process. After sacrifice operated tibiae were tested biomechanically for nondestructive torsion and compared to the tibia of the healthy opposite side. After testing specimens were processed for microradiography, histology, histomorphometry and assessment of calcium deposition by fluorescence microscopy.ResultsIn all groups bone healing occurred without complications. Stiffness in biomechanical testing showed a tendency for higher values in G2 but results were not statistically significant. Values for G5 were significantly lower after 6 weeks, but after 12 weeks values had improved to comparable results. For all groups, except G3, stiffness values improved between 6 and 12 weeks. Histomorphometrical data demonstrate endosteal callus to be more marked in G2 at 6 weeks.Discussion and conclusionAll five configurations resulted in undisturbed bone healing and are considered safe for clinical application.     

Biomechanical comparison of different acetabular plate systems and constructs--the role of an infra-acetabular screw placement and use of locking plates

IntroductionThe aim of this study was the direct comparison of the static fixation strength of two common plate systems: MPS (Matta Pelvic System) and LPPS (Low Profile Plate System). Furthermore the role of a modified screw placement with addressing the infra-acetabular corridor and the use of locking screws were evaluated.Materials and methodsCustom made anterior column fractures in artificial SYNBONE pelves were fixed with different acetabular plates (group I: MPS, group II: LPPS none locking and group III: LPPS locking). Each pelvis was tested twice, with the additionally placed infra-acetabular lag screw [+] first, followed by a repeated measurement without the infra-acetabular screw [?]. Six pelves per group were tested under static loading with six cycles up to 800 N, each. The fracture displacement was measured in the weight bearing dome using an ultrasound based Zebris-3D-Motion Analyzer.ResultsThe MPS-plate had a less fixation strength compared to the LPPS-plate (mean ± SD of maximum fracture displacement [mm] in group I vs. group II = 0.63 ± 0.02 vs. 0.37 ± 0.02, p < 0.05). The locking feature did not increase the fracture fixation strength (mean ± SD of maximum fracture displacement [mm] in group II vs. group III: 0.37 ± 0.02 vs. 0.37 ± 0.03; ns).The infra-acetabular screw significantly reduces the maximum fracture displacement in all groups, independent of the plate systems ([Delta%] in group I = 50; group II = 63 and group III = 40; p < 0.05 each).ConclusionThe LPPS-plate performed superior fixation strength for anterior column fractures compared to the MPS-plate. The locking plate modality did not reduce the maximum fracture displacement, whereas the additional infra-acetabular screw placement actually doubles the fracture fixation strength independent of the used plate system.     

Construct failure after open reduction and plate fixation of displaced midshaft clavicular fractures

IntroductionWorldwide, implants mostly used for fixation of displaced midshaft clavicular fractures (DMCF) are the easily to bend reconstruction plate and the stiffer small fragment locking compression plate. Construct failure rates after plate fixation of DMCF are reported around 5 percent. Possible risk factors for construct failure are implant type and fracture type. However, little is known about the influence of fracture fixation method on construct failure. The aim of this study was to assess construct failure in plate fixation of DMCF and to identify possible risk factors.MethodsAll consecutive patients treated in a level 1 trauma centre with open reduction and fixation of DMCF using a 3.5-mm reconstruction plate or 3.5-mm small fragment locking compression plate between 2007 and 2015 were evaluated. Potential risk factors for construct failure were analysed using univariate analysis.ResultsTwo hundred and fifty-nine patients were analysed. Fifty DMCF (19%) were fixated with a reconstruction plate and 209 (81%) with a small fragment locking compression plate. Construct failure was seen in 18 patients (6.9%), including 5 broken plates and 13 with screw loosening. Eight percent of all reconstruction plates broke in contrast to 0.5 percent of all small fragment locking compression plates (p = 0.001). All broken implants were used as a bridging plate. Loosening of screws was seen in older patients and when the plate was fixated with less than three bicortical screws on one side of the fracture (p = 0.002).ConclusionsOverall construct failure after open reduction and plate fixation of DMCF occurred in 6.9 percent. Risk factors for plate breakage were the use of a reconstruction plate and a bridging method for fracture fixation. Risk factors for screw loosening were an increasing patient age and plate fixation with less than three bicortical screws on one side of the fracture.RecommendationsBased on the results of this study our recommendation is to use a small fragment locking compression plate for open reduction and internal fixation of DMCF. The surgeon should always strive to fixate the plate on both sides of the fracture with at least three bicortical screws.     

Outcomes for four-part proximal humerus fractures treated with a locking compression plate and an autologous iliac bone impaction graft

ObjectivesThe study aims to evaluate outcomes of autologous iliac bone impaction grafts (AIBIGs) with locking-compression plates (LCPs) in four-part proximal humeral fracture.MethodsBetween October 2004 and October 2008, 21 AIBIG with LCP osteosyntheses were done for four-part proximal humeral fractures. Patients included seven males and 14 females. Their mean age at the time of the operation was 66.3 ± 16.9 years (range: 24–87 years). Five patients had high-energy fractures other than fall from standing height. There were two fracture-dislocation cases, and three valgus-impacted fractures. The length of the calcar segment attached to the articular segment was 7.04 ± 6.10 mm; 13 of the 21 cases had lengths less than 8 mm. Medial-hinge displacement was 16.77 ± 15.84 mm; 19 of the 21 cases had displacements more than 2 mm.ResultsThere was no avascular necrosis of the humeral head and union was achieved in all cases. Varus collapse and hardware-related complications were not observed. Postoperative neck-shaft angles were found to be 129 ± 9° (range: 109–146°). Neer scores were 92.0 ± 6.3 (range: 81–100).ConclusionThe results of using AIBIG with LCP for four-part proximal humeral fractures are excellent. There are significant bone defects in osteoporotic or comminuted fractures and LCP alone does not always provide reliable fixation. Therefore, meticulous technique and use of AIBIG in this complicated type of fracture can ensure a favourable outcome.     

Predictors of the postoperative range of finger motion for comminuted periarticular metacarpal and phalangeal fractures treated with a titanium plate

BackgroundPlate and screw fixation was introduced for complex fractures of the hand. Several risk factors for a poor functional outcome have been identified, but there is a paucity of evidence regarding predictors of finger stiffness in difficult hand fractures. The purpose of this prospective cohort study was to identify independent prognostic factors of the postoperative total active motion (%TAM) in the treatment of metacarpal and phalangeal fractures.MethodsSeventy-two patients (62 males, 10 females; 37 ± 15 years) with periarticular fractures involving metaphyseal comminution and displacement were evaluated at a minimum of 1 year following surgery. There were 49 phalangeal bone fractures, 30 intra-articular fractures and 20 associated soft-tissue injuries. The locations of plate placement were lateral in 42 patients and dorsal in 30. The mean duration from injury to surgery was 7.6 days (range, 0–40 days). There were eight examined variables related to patient characteristics (age, gender and hand dominance), fracture characteristics (fracture location, joint involvement and associated soft-tissue injury) and surgical variables (location of plate placement and duration from injury to surgery). Univariate and multivariate linear regression analysis were used to identify the degree to which variables affect %TAM at the final follow-up.ResultsUnivariate analysis indicated moderate correlations of %TAM with fracture location, associated soft-tissue injury and age. Multiple linear regression modelling including fracture location, age and associated soft-tissue injury resulted in formulae that could account for 46.3% of the variability in %TAM: fracture location (β = ?0.388, p < 0.001), age (β = ?0.339, p < 0.001) and associated soft-tissue injury (β = –0.296, p = 0.002).ConclusionPhalangeal fracture, increasing age and associated soft-tissue injury were important risk factors to identify the postoperative %TAM in the treatment of comminuted periarticular metacarpal or phalangeal fracture with a titanium plate.     

Finite element analysis of different repair methods of Vancouver B1 periprosthetic fractures after total hip arthroplasty

ObjectiveTo use finite element analysis to study the stability of different fixation methods used to repair Vancouver type B1 periprosthetic fractures occurring after total hip arthroplasty (THA).MethodsAn artificial femur was used as the basis for the solid model; U2 series femoral stem (United Orthopedic Corporation, Hsinchu, Taiwan) was used for modelling of the prosthesis; and the modelling of the cable plate, wires and screws was based on information given in the manufacturer's catalogue (Zimmer, Warsaw, IN, USA). The analysis model was constructed using the ANSYS software, and all material settings were based on literature values. A six-orifice cable plate, unicortical screws (20 mm long and 4.5 mm in diameter) and bicortical screws (50 mm long and 4.5 mm in diameter) were constructed. Four analysis models were defined. The basic model had a plate and three cable wires above the fracture line and two bicortical screws below the fracture line. In the second model, two unicortical screws were added above the fracture line. In the third model, three wires were added below the fracture line. In the fourth model, both the proximal screws of the second model and the distal wires of the third model were added to the basic model. To ensure that the numerical values produced by analysis reached convergence, mesh convergence was tested.ResultsAdding two proximal unicortical screws to the basic Ogden construct (plate, proximal wires and distal screws) lessened displacement of the fracture and decreased the von Mises stress on the repair. Adding three distal wires to the basic construct had no noticeable effect.ConclusionBetter fixation power is achieved by using both proximal and distal screws (the locking-plate concept) in treating Vancouver type B1 periprosthetic fracture after THA.     

Locking plate fixation of humeral head fractures with a telescoping screw. A comparative biomechanical study versus a standard plate

ObjectivesLocking plate fixation of humeral head fractures bares the risk of glenohumeral screw penetration. In order to circumvent this problem it is recommended to insert shorter locking screws having at least a 6 mm distance to the humeral head cortex. This in turn may reduce fixation stability and may lead to early varus displacement. One second frequent failure mechanism is cranial displacement of the greater tubercle. The study evaluates the biomechanical properties of a locking plate employing an additional telescoping screw that may enhance resistance to varus displacement. Screw in screw fixation of the greater tubercle may reduce the rate of cranial displacement.MethodsIn four paired fresh-frozen human cadaver humeri (age > 70 years) a Neer IV/3 fracture was created with a 5 mm osteotomy gap simulating metaphyseal comminution. Limbs were randomly assigned to receive plate fixation with an additional telescoping screw (Humerus Tele Screw: HTS) and on the contralateral limb Philos plate fixation before biomechanical evaluation (MTS-Bionix 858.2). Standard locking screws were placed in both groups 6 mm below the radiological head circumference; the telescoping screw was placed in the subchondral layer. The greater tubercle was fixed with an additional screw in both techniques, in the HTS group the screw was anchored in the sleeve of the telescrew (screw in screw fixation).FindingsFixation stability with a mean stiffness of 300.9 ± 28.8 N/mm in the HTS plate group proved to be significantly higher than in the Philos plate group (184.2 ± 23.4 N/mm; p = 0.006). The HTS plate also resisted higher loads in terms of fixation failure with loss of reduction at 290 ± 58.6 N in comparison to 205 ± 8.6 N for the Philos plate (p = 0.2). Displacement of the greater tubercle occurred in no case of the HTS plate group and in two out of four cases in the Philos plate group.InterpretationThe HTS plate provides high fixation stability in an in vitro humeral head fracture model and securely prevents displacement of the greater tubercle.     

Biomechanical analysis of second-generation headless compression screws

IntroductionHeadless Compression Screws (HCS) are commonly utilized for the fixation of small bone and articular fractures. Recently several new second generation HCS (SG-HCS) have been introduced with the purported benefits of improved biomechanical characteristics. We sought to determine and compare the biomechanical efficiencies of these screws.Material and methodsFive HCS including four second generation (Mini-Acutrak 2 (Acumed), Twinfix (Stryker), Kompressor Mini (Integra), HCS 3.0 (Synthes)) and one first generation (Herbert-Whipple) were studied. Polyurethane foam blocks that represented osteoporotic cancellous bone (0.16 g/cc) with a simulated transverse fracture at the waist were utilized and five screws of each brand were tested for the generated compression force and fastening torque during insertion with and without pre-drilling.ResultsThe generated compression force was highest for Mini-Acutrak 2 (45.41 ± 0.88 N) and lowest for Herbert-Whipple (13.44 ± 2.35 N) and forces of Twinfix, Kompressor Mini, HCS 3.0 were in between in descending order. The compression force of SG-HCS increased slightly without pre-drilling but it was not statistically significant while the fastening torque increased significantly. Slight over-fastening beyond the recommended stage significantly reduced the compression force in Twinfix and Kompressor and had no or moderate effect in other screws.ConclusionAll SG-HCS demonstrated greater biomechanical characteristics than the first generation Herbert-Whipple screw. The Mini-Acutrak 2 with a variable pitch design generated the maximum compression force and showed the most reliability and sustainability. Screws with independently rotating trailing heads (Twinfix and Kompressor Mini) demonstrated loss of compression with extra turns. The increase of fastening torque due to over-fastening and loss of compression at the same time in some screw designs, demonstrated how the fastening torque (applied by the surgeon) can be a misleading measure of the compression force. Application of SG-HCS in osteoporotic bone without pre-drilling can slightly increase the compression force.     

Minimally invasive percutaneous compression plating versus dynamic hip screw for intertrochanteric fractures: a randomized control trial

Objective：Intertrochanteric femur fracture is a common injury in elderly patients.The dynamic hip screw （DHS） has served as the standard choice for fixation; however it has several drawbacks.Studies of the percutaneous compression plate （PCCP） are still inconclusive in regards to its efficacy and safety.By comparing the two methods,we assessed their clinical therapeutic outcome.Methods：Atotal of 121 elderly patients with intertrochanteric femur fractures （type AO/OTA 31.A 1-A2,Evans type 1） were divided randomly into two groups undergoing either a minimally invasive PCCP procedure or a conventional DHS fixation.Results：The mean operation duration was significantly shorter in the PCCP group （55.2 min versus 88.5 min,P＜0.01）.The blood loss was 156.5 ml±18.3 ml in the PCCP group and 513.2 ml±66.2 ml in the DHS group （P＜0.01）.Among the patients treated with PCCP,3.1％ needed blood transfusions,compared with 44.6％ of those that had DHS surgery （P＜0.01）.The PCCP group displayed less postoperative complications （P＜0.05）.The mean American Society of Anesthesiologists score and Harris hip score in the PCCP group were better than those in the DHS group.There were no significant differences in the mean hospital stay,mortality rates,or fracture healing.Conclusion：Due to several advantages,PCCP has the potential to become the ideal choice for treating intertrochanteric fractures （type AO/OTA 31.A1-A2,Evans type 1）,particularly in the elderly.     

Moore I postero-medial articular tibial fracture in alpine skiers: Surgical management and return to sports activity

PurposeOver the past 10 years, like many authors, we observed an increasing number of Moore I tibial plateau fractures related to alpine skiing for which the surgeon may face difficult choices regarding surgical approach and fixation means. Some authors have recently been suggesting a posterior approach associated to open reduction and osteosynthesis by a buttress plate. But in our knowledge there is no specific study on sports activity recovery after Moore I tibial fractures. The aim of this work was to assess sports activities and clinical outcomes after surgically treated Moore I tibial plateau fractures in an athletic population of skiers.MethodsWe conducted a prospective case series between 2012 and 2014. This included fifteen patients aged 39.6 ± 7 years whom presented with a Moore I tibial plateau fracture during a skiing accident. 12 cases (80%) presented with an associated tibial spine fracture. Treatment consisted of a standard antero-medial approach, with a medial para patellar arthrotomy to allow direct visualisation of articular reduction and spinal fixation. Two or three 6.5 mm long cancellous bone screws were placed antero-posteriorly so as to ensure perfect compression of the fracture site. Radiological and functional results were assessed by an independent observer (Lysholm-Tegner, UCLA, KOOS scores) at the longest follow-up.ResultsMean follow-up was 18.2 ± 6 months (12–28). An immediate postoperative anatomical reduction was achieved in all cases and remained stable in time. At last follow-up Lysholm mean score was 85 ± 14 points (59–100), UCLA score was 7.3 ± 1.6 (4–10) and Tegner score was 4.6 ± 1.3 (3–6). Mean KOOS score was 77 ± 15 (54–97). 87% of patients had resumed their skiing activity and 93% were satisfied or very satisfied from their post-operative surgical outcome. We observed no pseudarthrosis or secondary varus displacement.ConclusionIn our series 87% of patients had resumed back to their sporting activities. Surgical management of Moore I tibial plateau fractures by isolated antero-posterior screwing provides excellent clinical and radiological results. The anteromedial incision has a dual advantage of anatomical reduction, tibial spine fixation (in 80% of our cases) and posteromedial fragment reduction.     

The biomechanical cost of variable angle locking screws

IntroductionVariable angle (VA) locking plates in fracture fixation surgery allow screws to be fastened to the plate within a conical “locus of vectors” in order to avoid existing prostheses, joint surfaces, or poor quality bone. Clinical failures of VA constructs in which screws have rotated at the plate/screw interface have been reported raising the concern that there may be a biomechanical cost for the increased flexibility that VA provides. The objective of this study was to test the mechanical properties of one commonly used VA locking mechanism with screws placed in both nominal and off–axis trajectories and compare these against the standard locking mechanism.MethodsVA locking screws were inserted into plates for distal femur fractures (VA Curved Condylar) at various angles (0° to 15° away from perpendicular). A control group of standard locking screws/plates was also tested. Maximum moment at the screw/plate interface and moment at two reference displacements were determined.ResultsVA screws locked perpendicular to the plate provided the greatest maximum moment and moment at the reference displacements when using the VA system, and demonstrated lower moments compared to standard locking screws/plates (p < 0.001). Based on linear regression, there was an average decrease of approximately 0.4 Nm screw-plate interface strength for every 1° increase in screw-plate angle (p < 0.001). Decreases (p<0.05) were discovered in both maximum moment and moment at the reference displacements for screws locked at 5° relative to those locked at 0°, 10° relative to 0°, and 15° relative to 10°.DiscussionStandard locking systems provided greater resistance to rotational failure at the screw/plate interface than variable angle locking systems. Variable angle systems provided the greatest resistance to rotation when the screw was inserted perpendicular to the plate. As the off-axis angle increased, the resistance to rotation at the screw/plate interface decreased almost linearly. It is unknown if these differences are clinically significant in an actual fracture construct, but recent reported failures in the distal femur suggest that they might be.ConclusionSurgeons should weigh the risks and benefits of VA systems and attempt to minimize the off-axis angle magnitude when VA systems are selected.     

Biomechanical evaluation of the tension band wiring principle. A comparison between two different techniques for transverse patella fracture fixation

PurposeThe aim of this study was to investigate the validity of the dynamic compression principle of tension band wiring in two techniques for patella fracture treatment.MethodsTwelve human cadaveric knees with simulated transverse patella fractures were assigned to two groups for treatment with tension band wiring using either Kirschner (K-) wires or cannulated screws. Biomechanical testing was performed over three knee movement cycles between 90° flexion and 0° full extension. Pressure distribution in the fracture gap and fracture site displacement were evaluated at the 3^rd cycle in 15° steps, namely 90°–75°–60°–45°–30°–15°–0° extension phase and 0°–15°–30°–45°–60°–75°–90° flexion phase.ResultsMean anterior / posterior interfragmentary pressure in the groups with K-wires and cannulated screws ranged within 0.16–0.40 MPa / 0.12–0.35 MPa and 0.37–0.59 MPa / 0.10–0.30 MPa, respectively. These changes remained non-significant for both groups and loading phases (P ≥ 0.171). Mean anterior / posterior fracture site displacement for K-wires and cannulated screws ranged within −0.01–0.53 mm / 0.11–0.74 mm and 0.11–0.55 mm / –0.10–0.50 mm, respectively. Anterior displacement remained without significant changes for both groups and loading phases (P ≥ 0.112). However, posterior displacement underwent a significant increase in the course of knee extension for K-wires (P ≤ 0.047), but not for cannulated screws (P ≥ 0.202). Significantly smaller displacement at the posterior fracture site was detected in the group with cannulated screws compared to K-wires at 60° and 75° extension phase (P ≤ 0.017), as well as at 45°, 60° and 75° flexion phase (P ≤ 0.018). The critical value of 2 mm displacement at the posterior fracture site was not reached for any specimen and fixation technique. Knee extension was accompanied by synchronous increase in quadriceps pulling force.ConclusionsTension band wiring fulfills from a biomechanical perspective the requirements for sufficient stability of transverse patella fracture fixation. It should, however, rather be considered as a static fixation principle than a dynamic one. Tension band wiring with cannulated screws was found advantageous over Kirschner wires in terms of interfragmentary movements at the posterior fracture site.