Introduction: Tarsometatarsal joint (TMTJ) fusion is performed for arthritis or painful deformity. First TMTJ fusion may be performed as a part of corrective surgery for hallux valgus deformity. K-wires and trans-articular screws are often used to stabilize the joints. We present our experience with the use of locking plates (LP) for TMTJ fusion. Patients and Methods: Thirty-three TMTJ’s in 19 patients were fused and stabilised with LP’s between January and September 2008. The procedure was performed for Lisfranc arthritis in 13 patients and Lapidus procedures in six. Two out of 6 were revisions after failed fusion using transarticular screws. Iliac crest bone autograft was used in 26 joints in 12 patients. All patients post-operatively had below knee plaster immobilization and protected weight bearing walking for first 6 weeks. Clinical and radiological surveillance continued until bone union. AOFAS midfoot scale was used as outcome measure. Results: There were 7 male and 12 female patients with average age of 51 (14–68). The American orthopaedic foot and ankle surgery society (AOFAS) midfoot score showed a 42% improvement in pain, 30% improvement in function and 53% improvement in alignment. The average AOFAS overall score improved from 30 preoperativley to 67 postoperativley. All except one joint in one patient had clinically and radiologically fused joints. One patient underwent removal of the metalwork and four had delayed wound healing. The average satisfaction score was 7 out of 10. 86% said of patients said that they would recommend the surgery to a friend, and 91% would undergo the surgery again. Discussion: Locking plates have been recently introduced for ankle and foot surgery. Biomechanical studies have shown that the plates are not as strong or stiff as trans-articular screw fixation, however, they are easy to use, have more flexibility for realignment and can act as a buttress for bone graft. In our series all, except one, patients achieved bony union without loss of alignment. Conclusion: Locking plates provide satisfactory stability for TMTJ fusion, without complications

Introduction: TMTJ fusion is performed for arthritis or painful deformity. First TMTJ fusion may be performed for Hallux valgus deformity. K-wire and trans-articular screws are usually used to stabilize the joints. We present our audit of experience with LP for TMTJ fusion. Patients and Methods: 33 TMTJ in 19 patients were fused and stabilised using LP between January and September 2008. The procedure was performed for Lisfranc arthritis in 13 and Lapidus procedure in 6. Two out of 6 were revisions after failed fusion using transarticular screws. Iliac crest bone autograft was used in 26 joints in 12 patients. All patients post-operatively had below knee plaster immobilization and protected weight bearing walking for first 6 weeks. Clinical and radiological surveillance continued until bone union. AOFAS mid-foot scale was also used as an outcome measure. Results: There were 7 male and 12 female patients with average age of 51 (14–68). AOFAS midfoot scale showed 42% improvement in pain, 30% improvement in function and 53% improvement in alignment. Average total AOFAS score improved from 30 preoperative to 67 postoperative. All except 1 joint in one patient had clinical and radiological fusion of their joints. 1 patient needed removal of metalwork and 4 had delayed wound healing. Average satisfaction score was 7/10. 86% Patients would recommend it to a friend and 91% would have it again. Discussion: Locking plates have been recently introduced for ankle and foot surgery. Biomechanical studies have shown plates are not as strong or stiff as trans-articular screw fixation however they are easy to use, have more flexibility for realignment and can act as a buttress for bone graft. In our review all patients except one had bone union without loss of alignment. Conclusion: TMTJ fusion improves pain and function. Locking plates provide satisfactory stability for TMTJ fusion

Purpose

To promote rapid bone healing, an adequate stable fixation implant with a percutaneous reduction instrument should be used for Vancouver type B1 or C fractures. The objective of this study was to describe radiographic and clinical outcomes of patients with periprosthetic fracture (PPF) around a stable femoral stem, treated with a distal femoral locking plate alone or with a cerclage cable.

Purpose. Locking plate constructs for proximal humerus fractures can fail due to varus collapse, especially in the presence of osteoporosis and comminution of the medial cortex. Augmentation using a fibular allograft as an intramedullary bone peg may strengthen fixation preventing varus collapse. This study compared the ability of the augmented locking plate construct to withstand repetitive varus stresses relative to the non-augmented construct in cadaveric specimens. Method. Proximal humerus fractures with medial comminution were simulated by performing wedge-shaped osteotomies at the surgical neck in cadaveric specimens. For each cadaver (n=8), one humeral fracture was fixated with the locking plate construct alone and the other with the locking plate construct plus ipsilateral fibular autograft augmentation. The humeral head was immobilized and a repetitive, medially-directed load was applied to the humeral shaft until failure (significant construct loosening or humeral head screw pull-out). Results. No augmented construct failed, withstanding either 20 000 cycles or five times the cycles of the contralateral non-augmented construct [average (standard deviation) = 27958 (4633) cycles], while six of the eight non-augmented constructs failed (p=0.007). Failure in the six non-augmented constructs occurred after an average of 5928 (2543) cycles. Conclusion. Fibular allograft augmentation increased the ability of the locking plate construct to withstand repetitive varus loading. Clinically, this may assist proximal humerus fracture fixation in osteoporotic bone with medial cortex comminution

Introduction and Aims: Locking plates represent a major change in the way we stabilise fractures. The distal radius Locking Compression Plate (LCP, Synthes) theoretically enables palmar plating of dorsally comminuted and intra-articular wrist fractures. All current methods (Dorsal plates, K wires and external fixators) have considerable disadvantages. This is the first study to assess the clinical and biomechanical results of this new implant. Method: We created a synthetic bone fracture model to compare three plates (the LCP, Buttress and Pi). We tested 24 plates, eight in each group, using the Instrom biomechanical testing machine, axially loading the model to 200 Newtons for 500 cycles. The results show significantly less displacement for the LCP plate (p< 0.05). Results: Early clinical results are reported following a prospective study of the LCP plate to stabilise dorsally comminuted and intra-articular. The average age was 32 years. We report our results at an average follow-up of six months (range four to nine months). There were no complications. The Gartland & Werley scores were at least satisfactory in all patients and good in 75%. Conclusion: Both our biomechanical and early clinical results support the clinical use of the palmarly applied LCP for intra-articular and dorsally comminuted wrist fractures

Introduction:. Mayo 2A Olecranon fractures are traditionally managed with a tension band wire device (TBW) but locking plates may also be used to treat these injuries. Objectives:. To compare clinical outcomes and treatment cost between TBW and locking plate fixation in Mayo 2A fractures. Methods:. All olecranon fractures admitted 2008–2013 were identified (n=129). Patient notes and radiographs were studied. Outcomes were recorded with the QuickDASH (Disabilies of Arm, Shoulder and Hand) score. Incidence of infection, hardware irritation, non-union, fixation failure and re-operation rate were recorded. Results:. 89 patients had Mayo 2A fractures (69%). Of these patients 64 underwent TBW (n=48) or locking plate fixation (n=16). The mean age for both groups were 57 (15–93) and 60 (22–80) respectively. In the TBW group, the final follow-up QuickDASH was 12.9, compared with 15.0 for the Locking plate group. There was no statistically significant difference between either group (p = 0.312). 19 of the 48 TBW patients had complications (48%). There was 1 infection (2%). 15 cases of metalwork irritation (31%). 1 non-union (2%). 2 fixation failures (4%). 14 of the 48 TBW patients had re-operations (29%). There were 13 removal of metalwork procedures (27%), 1 washout (2%) and 2 revision fixations (4%). There were 0 complications and 0 re-operations in the 16 patients who underwent locking plate fixation. This was statistically significant, (p = 0.003) and (p= 0.015) respectively. TBW costs £7.00 verses £244.10 for a locking plate. Theatre costs were equivalent. A 30 minute day surgery removal of metalwork or similar case costs £1420. In this cohort, when costs of re-operation were included, locking plates were on average £177 less per patient. Conclusions:. Locking plates are superior to TBW in terms of incidence of post-operative morbidity and re-operation rate. Financial savings may be made by choosing a more expensive initial implant

Treatment of syndesmotic injuries is a subject of ongoing controversy. Locking plates have been shown to provide both angular and axial stability and therefore could potentially control both shear forces and resist widening of the syndesmosis. The aim of this study is to determine whether a two-hole locking plate has biomechanical advantages over conventional screw stabilisation of the syndesmosis in this pattern of injury. Six pairs of fresh-frozen human cadaver lower legs were prepared to simulate an unstable Maisonneuve fracture. The limbs were then mounted on a servo-hydraulic testing rig and axially loaded to a peak load of 800N for 12000 cycles. Each limb was compared with its pair; one receiving stabilisation of the syndesmosis with two 4.5mm quadricortical cortical screws, the other a two-hole locking plate with 3.2mm locking screws (Smith and Nephew). Each limb was then externally rotated until failure occurred. Failure was defined as fracture of bone or metalwork, syndesmotic widening or axial migration >2mm. Both constructs effectively stabilised the syndesmosis during the cyclical loading within 1mm of movement. However the locking plate group demonstrated superior resistance to torque compared to quadricortical screw fixation (40.6Nm vs 21.2Nm respectively, p value <0.03). Conclusion. A 2 hole locking plate (3.2mm screws) provides significantly greater stability of the syndesmosis to torque when compared with 4.5mm quadricortical fixation

Introduction: Surgical treatment of most displaced proximal humerus fractures is challenging due to osteoporosis, which makes stable fixation difficult. Locking plates are intended to provide superior mechanical stability. The NCB. ®. -PH (Non-Contact-Bridging for the Proximal Humerus) plate is a locking plate of the latest generation that allows both open and minimally invasive (MI) application. Methods: In a prospective multicenter study 131 patients were treated (n = 78 open, n = 53 MI). The open procedure was performed using a standard deltopectoral approach; the MI technique involved percutaneous reduction and an anterolateral deltoid split approach. Clinical and radiological follow-up was obtained 6 weeks, 3, 6 and 12 months after surgery. An iADL (instrumental activities of daily living) score was used for functional assessment, the subjective outcome was measured using VAS (Visual Analogue Scale) for pain and mobility. Results: Improvement in function (ROM) was statistically significant in both groups (open and MI) postoperatively. Fracture type had the most significant impact on the complication rate. The most frequent complication was intraarticular screw perforation. The open treated group showed a higher complication rate. However, more C-type fractures (AO) were treated with this technique. Conclusion: The NCB-PH is suitable as a routine method of treatment for proximal humerus fractures. Complication rate and functional outcome are comparable to the literature. The MI technique, which is limited by percutaneous fracture reduction, provides a less invasive option for patients requiring fast recovery. Complex fractures should preferably be treated with the open technique

Complex proximal humerus fractures have been described as the unsolved fracture. Review of literature shows a variety of treatment methods and results. We present the results of a prospective study of 47 complex proximal humerus fractures treated by PHILOS (Proximal Humeral Internal Locking System) plate. The aim of this study was to assess the effectiveness of the PHILOS plate in the surgical treatment of Neer’s type 3 & 4 fractures. We operated upon 47 patients (mean age 56yrs) between March 2002 and January 2006 for fixation of 3 part (28 patients) and 4 part (19 patients) fractures at a level 1 trauma centre. An independent observer reviewed patients at 6 monthly intervals for clinical and radiological assessment. Outcome measures included DASH and Constant scores. 42 patients were available for follow up, which ranged from 12–66 (average 24.4) months. Recovery of movements, and relief in pain was satisfactory in most of the patients, but the strength of shoulder did not recover fully in any patient. There were two failures in our series, one due to breakage of plate and another due to non-union; both treated successfully by revision. 4 patients (8%) had radiological signs of avascular necrosis of humeral head but only 2 of them were symptomatic requiring further treatment. Pain due to impingement was noted in several patients leading to removal of plate (6 patients) and subacromial decompression (3 patients). We encountered the problem of cold welding and distortion of screw heads, while removing the plate. The broken plate was subjected to biomechanical and metallurgical analysis, which revealed that the plate is inherently weak at the site of failure. We concluded that in spite of the above-mentioned complications, the PHILOS plate is a reliable implant to fix 3 and 4 part proximal humeral fractures. We were particularly impressed with the satisfactory results of fixation in 4 part fractures. However, we are not convinced about its strength. The plate may cause impingement in some patients necessitating its removal later on, which itself may not be easy. Level of Evidence: Therapeutic study, level IV (case series)

Introduction. Distal radius fractures are one of the most common injuries attended in hospitals. Throughout the years the treatment has change from simple cast to ORIF. Objectives. To compare the functional and radiographic results in the treatment of the distal intrarticular radial fractures treated by volar buttress plate (T plate AO® Synthes, Oberdorf, Suiza) and fixed volar angle locking plate (DVR® Depuy, Warsaw, Indiana, USA). Material and Methods. We performed a comparative retrospective study between two series of patients treated by fixed volar angle locking plate (40 patients) or volar buttress plate (36 patients). Distal radius fractures were classified by the AO/ASIF Müller classification after X-ray study in two views (Anteroposterios and lateral views), surgical treatment was indicated by the type of fracture (unstable fractures) and open fractures. Demographic information was gathered, injury mechanism and postoperatory complications. The minimal follow-up was 10 months. We performed clinical and radiographic evaluations before surgery, postoperatory, to 3 months and at the end of the follow-up (Palmar tilt, radial inclination, radial height and the radioulnar index were measured). Lidström's and Quick Dash scale, by means of telephonic survey, were used for the functional evaluation. Results. The time from fracture to surgery was on average 3.74 days in the group of DVR ® plates and 1.69 days for the group treated with T buttress plates. Henry's approach was realized in every case and the average time spent in surgery was 74 minutes for patients treated with T buttress plate and 80 minutes for patients treated with plate DVR®. In some cases K wires had to be used in 9 cases in the DVR® group and 7 in the other group. DVR® group obtained better results in radiological evaluation except in the radial inclination. In the Quick Dash scale, conducted a telephone survey, the average for the DVR® group was 26.40 (CI: 13.6 to 81.8) and 33.37 (CI: 10.2–90) for the group of T buttress plate (p=0.055). Conclusion. The potential advantages of ORIF in the distal radius fractures are low complication rate, stable subchondral fixation and early active movement of the wrist in the postoperative period. The disadvantages are a high cost, greater complexity and surgical exposure. Locking plates were designed to prevent postoperative collapse of the fracture also allows a better fix system in osteoporotic bone. Both types of plates obtained good results radiological and functional at the end of follow-up but we have obtained better results in the patients treated with locking plates

Historically the management of distal radial fracture has been often inadequate. It can be difficult to internally fix complex distal radial fractures with conventional plates. The fracture often collapses with metalwork failure. Literature suggests that malunion may lead to painful wrist with loss of function. In recent years fixed angle locking plate has been advocated for treatment of complex distal radius fracture. Our aim was to assess to assess the effectiveness of the volar locking plate (DePuy) in maintaining fracture reduction in distal radial fractures.

Radiographs of 170 distal radius fractures treated by the DVR plate were analysed. Fractures were classified according to the Melone and AO classifications. The post injury, intra-operative, 6 weeks postoperative and final postoperative radiographs were reviewed to obtain measurements for radial height, radial slope and volar inclination. The measurements were correlated with fracture pattern, locking screw length, presence or absence of radial styloid screw and plate placement in relation to the wrist joint. The results were analysed statistically using Wilcoxon signed rank test.

Radiologically there was minor loss of radial height, slope and volar inclination but this was not statistically significant. There was a statistically significant correlation between complexity of fracture and loss of radiological parameters. There was no statistically significant correlation between loss of radiological parameters and screw length, plate placement or presence or absence of radial styloid screw.

The DVR volar locking plate appears to maintain a satisfactory reduction of the fracture except for some complex fractures with dorsal comminution in which case dorsoradial plates may be preferable.

Aims of study. To assess and compare the functional, radiological and cosmetic results as well as patient satisfaction in patients treated with the IMN Device Vs Volar Locking Plate. Method. All patients who presented to our institution with extra articular distal radius fractures and met the inclusion criteria were invited to take part in the study. The patients were randomly allocated to two groups, those who underwent intramedullary (IMN) distal radius fixation using the Sanoma Wrx Distal radius nail and those who underwent fixation using a volar locking plate. The patients were then followed up at 2 weeks, 6 weeks, 3 months, 6 months and 1 year. The radiological parameters, ie radial height, inclination and tilt were compared as well as the functional outcomes by means of DASH score. The range of motion of the wrist was compared as well as the scar size. Complications were reviewed. Results. We present our early results. Currently we have included 9 patients in the IMN group and 7 patients in the volar plate group with follow-ups longer than 3 months. Results show smaller scars (2.5 vs 6.7cm), comparable flexion and extension (40 vs 40 and 45 vs 40), slight improvements in pronation and supination (80 vs 75 and 85 vs 80) in the IMN compared to the volar plate. Radial and ulnar deviation is comparable. The radiological parameters showed slight improvements in the radial height (2.5 vs 2.2 mm), inclination (3.6 vs 3.2 degrees) and tilt 13,7 vs 12 degrees) with the IMN. Dash scores will be compared at 6 months. Conclusion. Intra medullary nailing of the distal radius seems to compare to volar plating in terms of radiological parameters and rotational stability but has the added benefit of early range of motion, minimal invasive technique, less post op pain and less complications such as tendon irritation. NO DISCLOSURES

Surgical education of fracture fixation biomechanics relies mainly on simplified illustrations to distill the essence of the underlying principles. These mostly consist of textbook drawings or hands-on exercises during courses, both with unique advantages such as broad availability and haptics, respectively. Computer simulations are suited to bridge these two approaches; however, the validity of such simulations must be guaranteed to teach the correct aspects. Therefore, the aim of this study was to validate finite element (FE) simulations of bone-plate constructs to be used in surgical education in terms of fracture gap movement and implant surface strain.

The validation procedure was conducted in a systematic and hierarchical manner with increasing complexity. First, the material properties of the isolated implant components were determined via four-point bending of the plate and three-point bending of the screw. Second, stiffness of the screw-plate interface was evaluated by means of cantilever bending to determine the properties of the locking mechanism. Third, implant surface strain and fracture gap motion were measured by testing various configurations of entire fixation constructs on artificial bone (Canevasit) in axial compression. The determined properties of the materials and interfaces assessed in these experiments were then implemented into FE models of entire fixation constructs with different fracture width and screw configurations. The FE-predicted implant surface strains and fracture gap motions were compared with the experimental results.

The simulated results of the different construct configurations correlated strongly with the experimentally measured fracture gap motions (R²>0.99) and plate surface strains (R²>0.95).

In a systematic approach, FE model validation was achieved successfully in terms of fracture gap motion and implant deformation, confirming trustworthiness for surgical education. These validated models are used in a novel online education tool OSapp (https://osapp.ch/) to illustrate and explain the biomechanical principles of fracture fixations in an interactive manner.

TMTJ fusion is performed for arthritis or painful deformity. K-wire and trans-articular screws are usually used to stabilize the joints. We present our experience with LP for TMTJ fusion in first 100 joints. Patients and methods. 100 TMTJ in 74 patients were fused and stabilised with LP between January 2007 and December 2010. The indication was Lisfranc arthritis and hallux valgus. Iliac crest bone autograft was used in 64 joints. Auto graft was used in 22/53 first TMT fusions. All patients post-operatively had below knee plaster immobilization and protected weight bearing walking for first 6 weeks. Clinical and radiological surveillance continued until bone. AOFAS midfoot scale was used as outcome measure. Results. There were 18 male and 56 female patients with average age of 51 (14 -68). AOFAS midfoot scale improved 42% for pain, 30% for function and 53% for alignment. Average AOFAS overall score improved from 30 pre-op to 67 post op. 95 joints had clinical and radiological fusion. 1 patient needed removal of metalwork and 3 had delayed wound healing and 4 had radiological non- . All non- s were in 1st TMTJ where bone graft failed and were revised. None of the lesser ray TMTJ had non- . Average satisfaction score was 7 out of 10. 86% said they would recommend it to a friend and 91% would have it again. Discussion. Biomechanical studies has shown plates are not as strong or stiff as trans-articular screw fixation however they are easy to use, have more flexibility and act as a buttress for autograft. Our results show that dorsal locking plate has satisfactory clinical out come with or without bone graft for lesser rays. 1st TMT fusion without bone graft has higher fusion rate compare to 3 failures in 22 1st TMTJ with bone graft. This is due to multiple factors including LP being not strong enough to sustain the stresses until creeping substitution through the bone graft. Conclusion. Locking plates provide satisfactory stability without complications for lesser ray with or without bone graft. Fusion for 1st TMTJ with auto bone graft has high failure of 13%

Four matched pairs of fresh frozen human femora were used to compare the biomechanical properties in axial and torsional loading of a Locking Condylar Plate and a retrograde intramedullary nail. One-centimeter gap osteotomy was created in the supracondylar region to simulate an AO/OTA 33-A3 fracture. The instrumented specimens were then mechanically tested under physiologic conditions in axial and torsional loading to determine the stability of the constructs. This laboratory study enhances the biomechanical advantages of the Locking Condylar Plate when fixation stiffness is essential. Devices with head locking screws provide angular rigidity and maximize fixation stability in osteopenic bone. To compare the biomechanical properties in axial and torsional loading of a Locking Condylar Plate and a retrograde intramedullary nail. To determine the modes of failure of these two devices under axial loading. Four matched pairs of fresh frozen human femora were used. Plain film radiographs and Dexa scanning were performed to evaluate bone quality and to screen for pathologic lesions. For each pair, one femur was stabilized with the Locking Condylar Plate and the other with a retrograde nail. One-centimeter gap osteotomy was created in the supracondylar region to simulate an AO/OTA 33-A3 fracture. Radiographs were obtained to exclude iatro-genic fractures before mechanical testing. The instrumented specimens were then mechanically tested under physiologic conditions in axial and torsional loading to determine the stability of the constructs. Three-dimensional displacement across the fracture site was recorded. Finally, all femurs were loaded to fracture under axial loading. The modes of failure were determined by assessing final radiographs. The Locking Condylar Plate provided statistically significant greater rigidity both in axial (p = 0.048) and torsional loading (p = 0.031) compared to the retrograde nail. The axial mode of failure occurred proximally for the plate and mainly at the distal fixation for the nail. This laboratory study enhances the biomechanical advantages of the Locking Condylar Plate when fixation stiffness is essential. Devices with head locking screws provide angular rigidity and maximize fixation stability in osteopenic bone

Distal radius fracture is one of the most common fractures in older women (∼70,000 cases annually in Canada). Treatment of this fracture has been shifting toward surgery (mainly volar locking plate (VLP) technology), which significantly enhances surgeon's ability to maintain correction. However, current surgical outcomes are far from perfect. There is a need for an implant which maintains the corrected position (reduction), minimizes soft tissue disruption, and is technically easy to perform. A novel internal, composite-based implant was designed to achieve these ends. It is unclear, however, whether this novel implant offers similar fracture fixation as the VLP. As such, the objective of this research was to evaluate the fracture stability (assessed by calculating change in fracture length) of the novel implant and VLP under cyclic fatigue loading.

Specimens: Seven radius specimens derived from older female cadavers (mean = 82.3 years, SD = 11.3 years) were used for the experiment.

Preparation: A standardized dorsal wedge was removed from the cortex. The distance from the proximal and distal transverse osteotomies was 10 mm and was positioned 20 mm proximal to the tip of the radial styloid. The osteotomy removed all load-bearing capabilities of bone, equivalent to a worst-case-scenario for DRF fixation.

Simulated Loading: The proximal end of the radii was potted (fixed) and positioned in a material testing system. To mimic natural loading conditions, hands were cycled between −30°/30° flexion/extension, at 0.5 Hz, for 2000 cycles, while tension load was applied to the tendons (25-N constant force per tendon, 100-N in total).

Mechanical testing outcomes: A position tracking sensor used to measure change in fracture length. This change, as a function of number of cycles, was used to assess implant resistance to fatigue loading.

Statistical Analysis: A paired student t-test was used to compare the change in fracture length. Level of significance was determined as 5% (p < 0.05).

Changes in fracture fracture-length for both the novel implant and plate is shown in Table 1. The paired t-test indicated significant differences between the two groups in terms of change in fracture length (p = 0.026).

The outcome of the novel implant ranged from very stable (change in fracture-length = 0.01 mm) to highly un-stable (2.88 mm). We believe the reason for this variance, at least in part, originates from the surgical procedures. Presumably, given that one very strong stabilization (0.01 mm) and one acceptable stabilization (0.37 mm) was obtained, future research directed towards surgical procedures may improve fracture stability.

For any figures or tables, please contact authors directly.

Distal radius fractures are the most common upper extremity injury, and are increasingly being treated surgically with pre-contoured volar-locking plates. These plates are favored for their low-profile template while allowing for rigid anatomic fixation of distal radius fractures. The geometry of the distal radius is extremely complex, and little evidence within the medical literature suggests that current implant designs are anatomically accurate. The main objective of this study is to determine if anatomic alignment of the distal radii corresponds accurately with modern volar-locking plate designs. Additionally, this study will examine sex-linked differences in morphology of the distal radius.

Segmented CT models of ten female cadaver (mean age, 88.7 ± 4.57 years, range, 82 – 97) arms, and ten male cadaver (mean age, 86 ± 3.59 years, range, 81 – 91) arms were created. Micro CT models were obtained for the DePuy Synthes 2.4mm Extra-articular (EA) Volar Distal Radius Plate (4-hole and 5-hole head), and 2.4mm LCP Volar Column (VC) Distal Radius Plate (8-hole and 9-hole head). Plates were placed onto the distal radii models in a 3D visualization software by a fellowship-trained orthopaedic hand surgeon. The percent contact, volar cortical angle (VCA), border and overlap of the watershed line (WSL) were measured.

Both sexes showed an increase in the average VCA measure from medial to lateral columns which was statistically significant. Female VCA ranged from 28 – 36 degrees, and 38 – 45 degrees for males. WSL overlap ranged from 0 – 34.7629% for all specimens without any statistical significance. The average border distance for females was 2.58571 mm, compared to 3.52411 mm for males, with EA plates having a larger border than VC plates. The border distances had statistically significant differences between the plate types, and was approaching significance between sexes. Lastly, a maximum percent contact of 21.966 % was observed in specimen F4 at a 0.3 mm threshold. No statistical significance between plate or sex populations was observed.

This study investigated the incoherency between the volar cortical angle of the distal radius, and the pre-contoured angle of volar locking plates. It was hypothesized that if the VCA measures between plate and bone were unequal then there would be an increase in watershed line overlap, and decrease in percent contact between the surfaces. Our results agreed with literature, indicating that the VCA of bone was larger than that of the EA and VC pre-contoured plates examined in this study.

With distal radius fracture incidences and prevalence on the rise for elderly female patients, it is a necessity that volar locking plates be re-designed to factor in anatomical features of individual patients with a particular focus on sex differences. New designs should focus on providing smaller head sizes that are more accurately tailored to the natural contours of the volar distal radius. It is recommended that future studies incorporate expertise from multiple surgeons to diversify and further understand plate placement strategies.

Stand-alone anterior lumbar interbody fusion (ALIF) provides the opportunity to avoid supplemental posterior fixation. This may reduce morbidity and complication rate, which is of special interest in patients with reduced bone mineral density (BMD). This study aims to assess immediate biomechanical stability and radiographic outcome of a stand-alone ALIF device with integrated screws in specimens of low BMD.

Eight human cadaveric spines (L4-sacrum) were instrumented with SynFix-LR™ (DePuy Synthes) at L5/S1. Quantitative computed tomography was used to measure BMD of L5 in AMIRA. Threshold values proposed by the American Society of Radiology 80 and 120 mg CaHa/mL were used to differentiate between Osteoporosis, Osteopenia, and normal BMD. Segmental lordosis, anterior and posterior disc height were analysed on pre- and postoperative radiographs (Fig 1). Specimens were tested intact and following instrumentation using a flexibility protocol consisting of three loading cycles to ±7.5 Nm in flexion-extension, lateral bending, and axial rotation. The ranges of motion (ROM) of the index level were assessed using an optoelectronic system.

BMD ranged 58–181mg CaHA/mL. Comparison of pre- and postoperative radiographs revealed significant increase of L5/S1 segmental lordosis (mean 14.6°, SD 5.1, p < 0.001) and anterior disc height (mean 5.8mm, SD 1.8, p < 0.001), but not posterior disc height. ROM of 6 specimens was reduced compared to the intact state. Two specimens showed destructive failure in extension. Mean decrease was most distinct in axial rotation up to 83% followed by flexion-extension.

ALIF device with integrated screws at L5/S1 significantly increases segmental lordosis and anterior disc height without correlation to BMD. Primary stability in the immediate postoperative situation is mostly warranted in axial rotation. The risk of failure might be increased in extension for some patients with reduced lumbar BMD, therefore additional posterior stabilization could be considered.

For any figures or tables, please contact the authors directly.

Distal radius fractures are the most common osteoporotic fractures among women. The treatment of these fractures has been shifting from a traditional non-operative approach to surgery, using volar locking plate (VLP) technology. Surgery, however, is not without risk, complications including failure to restore an anatomic reduction, fracture re-displacement, and tendon rupture. The VLP implant is also marked by bone loss due to stress-shielding related to its high stiffness relative to adjacent bone. Recently, a novel internal, composite-based implant, with a stiffness less than the VLP, was designed to eradicate the shortcomings associated with the VLP implant. It is unclear, however, what effect this less-stiff implant will have upon adjacent bone density distributions long-term. The objective of this study was to evaluate the long-term effects of the two implants (the novel surgical implant and the gold-standard VLP) by using subject-specific finite element (FE) models integrated with an adaptive bone formation/resorption algorithm.

Specimen: One fresh-frozen human forearm specimen (female, age = 84 years old) was imaged using CT and was used to create a subject-specific FE model of the radius.

Finite element modeling: In order to simulate a clinically relevant (unstable) fracture of the distal radius, a wedge of bone was removed from the model, which was approximately 10 mm wide and centered 20 mm proximal to the tip of the radial styloid.

Bone remodeling algorithm: A strain-energy density (SED) based bone remodeling theory was used to account for bone remodeling. With this approach, bone density decreased linearly when SED per bone density was less than 67.5 µJ/g and increased when it was more than 232.5 µJ/g. When it was in the lazy zone (67.5 to 232.5 µJ/g), no changes in density occurred.

Boundary conditions: A 180 N quasi-static force representing the scaphoid, and a 120 N quasi-static force representing the lunate was applied to the radius. The midshaft of the radius was constrained.

FE outcomes: To examine the effects of stress shielding associated with each implant, the long-term changes of bone density within proximal transverse cross-sections of radius were inspected. The regional density analysis focused on three transverse cross-sections. The transverse cross-sections were positioned proximal to the subchondral plate, and were distanced 50 (cross-section A), 57 (cross-section B), and 64 mm (cross-section C) from the subchondral endplate.

For both implants in all three cross-sections, cortical bone was reserved completely at the volar side. On the dorsal side, the cortical bone was completely resorbed in the VLP model. In all cross-sections, the averaged resultant density was higher for the “novel implant”. The difference ranged from 33% (cross-section A) to 36% (cross-section C) in favor of the “novel implant”. On average, the density values of the novel implant were 34% higher in transverse cross-sections (A, B, and C).

This study showed that the novel implant offered higher density distributions compared to the VLP, which suggests that the novel implant may be superior to the VLP in terms of avoiding stress shielding.

Treatment of proximal humerus fractures (PHF) is controversial in many respects, including the choice of surgical approach for fixation when using a locking plate. The classic deltopectoral (DP) approach is believed to increase the risk of avascular necrosis while making access to the greater tuberosity more difficult. The deltoid split (DS) approach was developed to respect minimally invasive surgery principles. The purpose of the present study (NCT-00612391) was to compare outcomes of PHF treated by DP and DS approaches in terms of function (Q-DASH, Constant score), quality of life (SF12), and complications in a prospective randomized multicenter study.

From 2007 to 2016, all patients meeting the inclusion/exclusion criteria in two University Trauma Centers were invited to participate in the study. Inclusion criteria were: PHF Neer II/III, isolated injury, skeletal maturity, speaking French or English, available for follow-up (FU), and ability to fill questionnaires. Exclusion criteria: Pre-existing pathology to the limb, patient-refusing or too ill to undergo surgery, patient needing another type of treatment (nail, arthroplasty), axillary nerve impairment, open fracture. After consent, patients were randomized to one of the two treatments using the dark envelope method. Pre-injury status was documented by questionnaires (SF12, Q-DASH, Constant score). Range of motion was assessed. Patients were followed at two weeks, six weeks, 3-6-12-18-24 months. Power calculation was done with primary outcome: Q-DASH.

A total of 92 patients were randomised in the study and 83 patients were followed for a minimum of 12 months. The mean age was 62 y.o. (+- 14 y.) and 77% were females. There was an equivalent number of Neer II and III, 53% and 47% respectively. Mean FU was of 26 months. Forty-four patients were randomized to the DS and 39 to the DP approach. Groups were equivalent in terms of age, gender, BMI, severity of fracture and pre-injury scores. All clinical outcome measures were in favor of the deltopectoral approach. Primary outcome measure, Q-DASH, was better statistically and clinically in the DP group (12 vs 26, p=0,003). Patients with DP had less pain and better quality of life scores than with DS (VAS 1/10 vs 2/10 p=0,019 and SF12M 56 vs 51, p=0,049, respectively). Constant-Murley score was higher in the DP group (73 vs 60, p=0,014). However, active external rotation was better with the DS approach (45° vs 35°). There were more complications in DS patients, with four screw cut-outs vs zero, four avascular necrosis vs one, and five reoperations vs two. Calcar screws were used for a majority of DP fixations (57%) vs a minority of DS (27%) (p=0,012).

The primary hypothesis on the superiority of the deltoid split incision was rebutted. Functional outcome, quality of life, pain, and risk of complication favoured the classic deltopectoral approach. Active external rotation was the only outcome better with DS. We believe that the difficulty of adding calcar screws and intramuscular dissection in the DS approach were partly responsible for this difference. The DP approach should be used during Neer II and III PHF fixation.