Comparison of Ligament-Repair Techniques for the Syndesmosis: A Simulated Cadaveric Weight-Bearing Computed Tomography Analysis.

Although the literature describes a variety of reconstructive techniques for the syndesmosis, only few studies offer comparative data. Therefore, the authors compared 2 different ligament repair techniques for the syndesmosis. Sixteen paired fresh-frozen human cadaveric lower limbs were embedded in polymethyl methacrylate mid-calf and placed in a custom-made weightbearing simulation frame. Computed tomography scans of each limb were obtained in a simulated foot-flat loading (75N) and single-leg stance (700N) in 5 different foot positions (previously reported data). One of each pair was then reconstructed via 1 of 2 methods: a free medial Achilles tendon autograft or a long peroneal tendon ligament repair. The specimens were rescanned, compared with their respective intact states and directly with each other. Measurements of fibular diastasis, rotation, anteroposterior translation, mediolateral translation, and fibular shortening were performed on the axial cuts of the computed tomography scans, 1 cm proximal to the roof of the plafond. There was no significant difference in fibular positioning with direct comparison of the reconstructions. Comparisons with their respective intact states, however, showed differences in their abilities to control reduction, most notably in the externally rotated and dorsiflexed positions of the foot. Neither reconstruction was clearly superior in restoring physiologic conditions. Only with a comparison of each technique to its respective intact state were differences between the techniques revealed, a benefit of this particular testing method.

Fibrodysplasia ossificans progressiva (stone man syndrome): a case report.

BACKGROUND: Fibrodysplasia ossificans progressiva is an ultrarare autosomal dominant disorder and disabling syndrome characterized by postnatal progressive heterotopic ossification of the connective tissue and congenital malformation of the big toes. Fibrodysplasia ossificans progressiva has worldwide prevalence of about 1 in 2 million births. Nearly 90% of patients with fibrodysplasia ossificans progressiva are misdiagnosed and mismanaged and thus undergo unnecessarily interventions. So far, the number of reported existing cases worldwide is about 700. Clinical examination, radiological evaluation, and genetic analysis for mutation of the ACVR1 gene are considered confirmatory tools for early diagnosis of the disease. Association of fibrodysplasia ossificans progressiva with heterotopic ossification is well documented; however, postsurgical exaggerated response has never been reported previously, to the best of our knowledge. CASE PRESENTATION: We report a case of a 10-year-old Pakistani boy brought by his parents to our institution. He had clinical and radiological features of fibrodysplasia ossificans progressive and presented with multiple painful lumps on his back due to hard masses and stiffness of his shoulders, neck, and left hip. He underwent surgical excision of left hip ossification followed by an exaggerated response in ossification with early disability. Radiological examination revealed widespread heterotopic ossification. All of his laboratory blood test results were normal. CONCLUSION: Fibrodysplasia ossificans progressiva is a very rare and disabling disorder that, if misdiagnosed, can lead to unnecessary surgical intervention and disastrous results of early disability. We need to spread knowledge to physicians and patients' family members about the disease, as well as its features for early diagnosis and how to prevent flare-up of the disease to promote better quality of life in these patients.

Computed Tomography Analysis for Quantification of Displacement of the Distal Fibula in Different Foot Positions With Weightbearing and Sequentially Increased Instability: An Anatomic Cadaveric Study on Syndesmosis.

Syndesmotic injuries are quite common, but accurate diagnosis and treatment can be difficult, in part because of individual anatomic variation and complex movements of the fibula in the incisura. The current cadaveric study was designed to investigate changes in the position of the fibula in the incisura during simulated weightbearing in different foot positions and with sequential sectioning of syndesmotic and deltoid ligaments. Sixteen paired, fresh-frozen cadaveric limbs were embedded in polymethylmethacrylate mid-calf and placed in a weightbearing simulation frame. Computed tomography scans were obtained while the legs were in a simulated foot-flat position (75 N) and single-leg stance (700 N) in 5 foot positions: neutral, 15° external rotation, 15° internal rotation, 20° dorsiflexion, and 20° plantar flexion. The anterior-inferior tibiofibular ligament, posterior tibiofibular ligament complex, deltoid, and interosseous membranes were sectioned sequentially and rescanned. Measurements of fibular diastasis, rotation, anterior-posterior and medial-lateral translation, and fibular shortening were performed. The most destructive state resulted in the largest displacement at the syndesmosis. The degree of subluxation in all ligament states was dependent on the foot position. External rotation created statistically significant displacement at all levels of injury. There were no significant differences between sides of the same donor. Our data demonstrate the importance of foot position in reduction at the syndesmosis under weightbearing. The current ex vivo model could be used to evaluate other aspects of this injury or the value of reconstructive techniques in the future.

Effect of different multiplanar reformation algorithms on image quality of intraoperative three-dimensional fluoroscopy.

Different multiplanar reformation (MPR-512 and -256) algorithms of intraoperative acquired 3-D-fluoroscopy data exist without recommendations for use in the literature. To compare algorithms, 3-D-fluoroscopic data sets of 46 radius fractures were blinded and processed using MPR-256 and -512 (Ziehm, Vision-Vario 3D). Each reformatted data set was analysed to evaluate image quality, fracture reduction quality and screw misplacements. Overall image quality was higher rated in the MPR-512 compared with the MPR-256 (3.2 vs. 2.2 points, scale 1-5 points), accompanied by a reduced number of scans that could not be analysed (10 vs. 19%). Interobserver evaluation of fracture reduction quality was fair to moderate (independent of the algorithm). In contrast, for screw misplacements MPR-depended ratings were found (MPR-256: fair to moderate; MPR-512: moderate to substantial). Optimization of post-processing algorithms, rather than modifications of image acquisition, may increase the image quality for assessing implant positioning, but limitations in evaluating fracture reduction quality still exist.

Tangential View and Intraoperative Three-Dimensional Fluoroscopy for the Detection of Screw-Misplacements in Volar Plating of Distal Radius Fractures.

BACKGROUND: Volar locking plate fixation has become the gold standard in the treatment of unstable distal radius fractures. Juxta-articular screws should be placed as close as possible to the subchondral zone, in an optimized length to buttress the articular surface and address the contralateral cortical bone. On the other hand, intra-articular screw misplacements will promote osteoarthritis, while the penetration of the contralateral bone surface may result in tendon irritations and ruptures. The intraoperative control of fracture reduction and implant positioning is limited in the common postero-anterior and true lateral two-dimensional (2D)-fluoroscopic views. Therefore, additional 2D-fluoroscopic views in different projections and intraoperative three-dimensional (3D) fluoroscopy were recently reported. Nevertheless, their utility has issued controversies. OBJECTIVES: The following questions should be answered in this study; 1) Are the additional tangential view and the intraoperative 3D fluoroscopy useful in the clinical routine to detect persistent fracture dislocations and screw misplacements, to prevent revision surgery? 2) Which is the most dangerous plate hole for screw misplacement? PATIENTS AND METHODS: A total of 48 patients (36 females and 13 males) with 49 unstable distal radius fractures (22 x 23 A; 2 x 23 B, and 25 x 23 C) were treated with a 2.4 mm variable angle LCP Two-Column volar distal radius plate (Synthes GmbH, Oberdorf, Switzerland) during a 10-month period. After final fixation, according to the manufactures' technique guide and control of implant placement in the two common perpendicular 2D-fluoroscopic images (postero-anterior and true lateral), an additional tangential view and intraoperative 3D fluoroscopic scan were performed to control the anatomic fracture reduction and screw placements. Intraoperative revision rates due to screw misplacements (intra-articular or overlength) were evaluated. Additionally, the number of surgeons, time and radiation-exposure, for each step of the operating procedure, were recorded. RESULTS: In the standard 2D-fluoroscopic views (postero-anterior and true lateral projection), 22 screw misplacements of 232 inserted screws were not detected. Based on the additional tangential view, 12 screws were exchanged, followed by further 10 screws after performing the 3D fluoroscopic scan. The most lateral screw position had the highest risk for screw misplacement (accounting for 45.5% of all exchanged screws). The mean number of images for the tangential view was 3 ± 2.5 images. The mean surgical time was extended by 10.02 ± 3.82 minutes for the 3D fluoroscopic scan. An additional radiation exposure of 4.4 ± 4.5seconds, with a dose area product of 39.2 ± 14.5 cGy/cm(2) were necessary for the tangential view and 54.4 ± 20.9 seconds with a dose area product of 2.1 ± 2.2 cGy/cm(2), for the 3D fluoroscopic scan. CONCLUSIONS: We recommend the additional 2D-fluoroscopic tangential view for detection of screw misplacements caused by overlength, with penetration on the dorsal cortical surface of the distal radius, predominantly observed for the most lateral screw position. The use of intraoperative 3D fluoroscopy did not become accepted in our clinical routine, due to the technical demanding and time consuming procedure, with a limited image quality so far.

Biomorphometric analysis of ilio-sacro-iliacal corridors for an intra-osseous implant to fix posterior pelvic ring fractures.

It is hypothesized that ilio-sacro-iliacal corridors for a new envisioned pelvic ring implant (trans-sacral nail with two iliacal bolts = ISI-nail: ilio-sacro-iliacal nail) exists on the level of S1- or S2-vertebra in each patient. The corridors of 84 healthy human pelves (42x ♂; 42x ♀, 18-85 years) were measured in high resolution CT scans using the Merlin Diagnostic Workcenter Software. Trans-sacral corridors (≥ 9 mm diameter) on the level of S1 and S2 were found in 62% and 54% of pelves with a mean length [mm ± SD] of 164 ± 12.9 and 142 ± 10.2. Corresponding iliac corridors were present in all specimens in caudally tilted axial planes of 37.8 ± 0.67° and 53.7 ± 0.94° in relation to the operating table plane and divergent angulations of 69.0 ± 0.49° and 70.1 ± 0.32° in relation to the sagittal midline plane. Sacral dysmorphism, with compensatory larger S2 corridors were prevalent in 24% of pelves; ilio-sacro-iliacal osseous corridors for the envisioned implant were found in 88% of pelves on the level of S1 or S2. In the remaining 12% with too narrow corridors for any trans-sacral implant (screws, bars, ISI nail) alternative fixation methods have to be considered. Expected advantages of the envisioned ISI nail compared to available fixation devices are discussed.

Biomechanical comparison of a lateral polyaxial locking plate with a posterolateral polyaxial locking plate applied to the distal fibula.

BACKGROUND: Polyaxial locking plates are becoming popular for the fixation of distal fibula fractures. This study establishes how construct stiffness and plate loosening, measured as range of motion, differs between lateral and posterolateral plate location. METHODS: Seven matched pairs of cadaver fibulae were osteotomized in standardized fashion to produce a Weber type B distal fibula fracture. The fragments were fixated with an interfragmentary lag screw and polyaxial locking plates, with one fibula in each pair receiving a posterolateral anti-glide-plate, and the other a lateral neutralization-plate. In a biomechanical test, the bending and torsional stiffnesses of the constructs and the ranges of motion (ROM) were measured and subjected to a paired comparison. RESULTS: The laterally plated group had a higher median (interquartile range) bending stiffness (29.2 (19.7) N/mm) and a smaller range of motion (2.06 (1.99) mm) than the posterolaterally plated group (14.6 (20.6) N/mm, and 4.11 (3.28) mm, respectively); however, the results were not statistically significant (pbending=0.314; pROM=0.325). Similarly, the torsional stiffness did not differ significantly between the two groups (laterally plated: 426 (259) Nmm/°; posterolaterally plated: 248 (399) Nmm/°; ptorsion=0.900). The range of motion measurements between the two groups under torsional loading were also statistically insignificant (laterally plated: 8.88 (6.30) mm; posterolaterally plated: 15.34 (12.64) mm; pROM=0.900). CONCLUSION: In biomechanical cadaver-model tests of Weber type B fracture fixation with polyaxial locking plates, laterally plated constructs and posterolaterally plated constructs performed without significantly difference. Therefore, other considerations, such as access morbidity, associated injuries, patient anatomy, or surgeon's preference, may guide the choice of plating pattern. Further clinical studies will be needed for the establishment of definitive recommendations. CLINICAL RELEVANCE: Information on the behavior of polyaxial locking plates is relevant to surgeons performing internal fixation of distal fibula fractures.

A biomechanical comparison of fixed angle locking compression plate osteosynthesis and cement augmented screw osteosynthesis in the management of intra articular calcaneal fractures.

PURPOSE: The purpose of this study was to investigate whether cement-augmented screw osteosynthesis results in stability comparable to conventional fixed-angle locking plate osteosynthesis using cadaveric bones to model a Sanders type 2B fracture. METHODS: Seven pairs of fresh frozen human calcanei and the corresponding tali were used. The specimens were assigned pairwise to two study groups in a randomised manner. In order to determine the initial quasi-static stiffness of the bone-implant construct, testing commenced with quasi-static compression ramp loading; subsequently, sinusoidal cyclic compression loading at 2 Hz was performed until construct failure occurred. Initial dynamic stiffness (cycle 1), range of motion (ROM), cycles to failure and load to failure were determined from the machine data during the cyclic test. In addition, at 250-cycle intervals, Böhler's angle and the critical angle of Gissane were determined on mediolateral X-rays shot with a triggered C-arm; 5° angle flattening was arbitrarily defined as a failure criterion. RESULTS: Bone mineral density was normally distributed without significant differences between the groups. The augmented screw osteosynthesis resulted in higher stiffness values compared to the fixed-angle locking plate osteosynthesis. The fracture fragment motion in the locking plate group was significantly higher compared to the group with augmented screw osteosynthesis. CONCLUSIONS: The results of this study indicate that in our selected test set-up augmented screw osteosynthesis was significantly superior to the conventional fixed-angle locking plate osteosynthesis with respect to primary stability and ROM during cyclic testing.

Anatomical evaluation of different approaches for tibiotalocalcaneal arthrodesis.

BACKGROUND: The transfibular approach is commonly used for tibiotalocalcaneal arthrodesis. However, the medial and the posterolateral approaches are available as alternatives. The present study was performed to assess the effects of the 3 approaches on the neurovascular structures encountered and to quantify the extent of cartilage in the different joint compartments that could be surgically debrided. METHODS: This cadaver study was performed in 6 pairs of formalin-fixed legs (mean donor age: 80 years; 4 females, 2 males). For each approach, 4 specimens were selected. The neurovascular structures at risk and the debrided portions of the articular cartilage were compared. RESULTS: Arterial structures were least compromised by the transfibular approach. The posterolateral approach was particularly likely to damage the lateral malleolar branches of the peroneal artery. Venous structures were at risk mainly from the medial approach, which was also the most risk-bearing of the 3 approaches in terms of nerve damage. The proportions of cartilage-debrided joint surfaces of the tibia in the ankle joint, and of the talus and the calcaneus in the subtalar joint, did not differ notably. The proportions of debrided surfaces of the talus in the ankle joint differed notably among the 3 approaches. CONCLUSIONS: The medial approach could be a valid alternative to the lateral transfibular approach for tibiotalocalcaneal arthrodesis. Care should be taken, however, to prevent damage to the saphenous nerve and other neurological structures. CLINICAL RELEVANCE: Access morbidity and feasibility of adequate cartilage debridement are relevant to the clinical outcome of hindfoot arthrodesis.

Adjustment of traumatic femur shortening assisted by an intramedullar skeletal kinetic distractor: a case report.

INTRODUCTION: Distal comminuted femoral fractures with joint involvement are highly challenging for the surgeon. We present a potential therapeutic concept that aims especially at the treatment of posttraumatic leg length discrepancy. CASE PRESENTATION: This case report describes a polytraumatized 19-year-old German woman. Among other injuries she had a third grade open distal comminuted femoral fracture with a long distance metaphyseal osseous defect. As a primary care procedure an external fixation was applied at first. On day 13, an open reconstruction of her distal femur and the articular surface was performed by screw osteosynthesis, shortening and intramedullary nailing. Due to delayed osseous consolidation an autologous cancellous bone grafting was performed twice. In addition to the second cancellous bone graft an allogeneic cortical bone graft was implemented. A 6.5cm posttraumatic leg length shortening after osseous consolidation was the result. The entire leg length shortening was successfully treated 16 months after her accident with the help of an intramedullar skeletal kinetic distractor. CONCLUSIONS: With the help of the current case report of a patient with polytrauma and a third grade open distal comminuted femoral fracture with joint involvement and a long distance osseous defect, we present a potential therapeutic concept that aims especially at the treatment of posttraumatic leg length discrepancy.

Percutaneous navigated screw fixation of glenoid fractures.

BACKGROUND: Open or percutaneous arthroscopic-based procedures are reported to fix unstable or displaced intra-articular glenoid fractures. Approach related morbidity has to be considered for open procedures, and arthroscopic-based procedures are demanding. Therefore an alternative percutaneous navigated approach is described. TECHNICAL PROCEDURE: In an experimental setting an operative workflow was simulated to evaluate the best position of the patient on the operation table, the operating room set up and the fixation technique for the dynamic reference base of the navigation system. Based on two clinical cases, screw fixation of glenoid fractures via a posterior percutaneous approach is described, using a 2D-fluoroscopic based navigation system. Compared to the common approaches, the advantages and disadvantages of this procedure are discussed. CONCLUSION: The described technique of percutaneous navigated screw fixation of glenoid fractures is an alternative minimal invasive procedure. A reduction of approach related morbidity and more rapid return to function could be expected. The intraoperative results and postoperative functional outcome of both cases are promising.

Volar versus dorsal latest-generation variable-angle locking plates for the fixation of AO type 23C 2.1 distal radius fractures: a biomechanical study in cadavers.

INTRODUCTION: Anatomicaly preformed variable-angle locking plates are technologically mature and appear to be optimal for the fixation of distal radius fractures. However, there is still much argument about whether volar plating is equivalent to dorsal (buttressing) plating, especially in the management of intra-articular extension fractures. This biomechanical study was performed to determine, in a simple intra-articular fracture model, whether dorsal or volar plate constructs would be more stable. MATERIALS AND METHODS: Six pairs of fresh frozen radii were examined with dual-energy absorptiometry (DXA) to determine their bone mineral density (BMD). An AO type 23 C2.1 fracture was created. Volar fixation was with a 2.4mm Variable-Angle LCP Two-Column Volar Distal Radius Plate; dorsal fixation was with two orthogonal 2.4 mm Variable-Angle LCP Dorsal Distal Radius Plates (both devices: Synthes, Oberdorf, Switzerland). Biomechanical testing used a proven protocol involving static tests of stiffness, and a cyclic test to obtain range of motion (ROM), maximum deformation, and subsidence data. RESULTS: None of the constructs failed during biomechanical testing. The two groups (volar and dorsal plating, respectively) did not differ significantly in terms of initial (pre-cyclic-testing) and final (post-cyclic-testing) stiffness. Equally, there was no significant difference between the subsidence values in the two groups. The post-cyclic-testing ROM was significantly greater in the dorsal-plate group as compared with the volar-plate group. The volar constructs showed a significant decrease in the ROM between pre- and post-cyclic testing. CONCLUSION: Biomechanically, volar plating with a modern variable-angle locking plate is equivalent to dorsal plating with two modern variable-angle locking plates.

Removal of a femoral nail with osseous overgrowth at the end-cap: A navigated and cannulated minimally invasive technique.

Intramedullary nail removal can be demanding, especially in cases of implant breakage or bony overgrowth at the end-cap, if the exact insertion depth of the nail is neglected in the index surgery. In the presented case, two challenging nail removals were necessary. The first was performed in a re-nailing procedure due to a pseudarthrosis with implant breakage, and the second was performed during hardware removal after fracture healing in a situation where there was deep intramedullary placement of the exchange nail. For the second implant removal a minimally invasive approach based on instrument placements over a navigated guide-wire was used to reduce the iatrogenic morbidity associated with an extensive open approach to the nail and to decrease the radiation exposure for the patient and the operating team.

Utility of the cortical thickness of the distal radius as a predictor of distal-radius bone density.

BACKGROUND: Bone density is an important factor in the management of fractures of the distal radius. OBJECTIVES: The aim of this study was to establish whether standard anteroposterior (AP) radiographs would provide the attending physician with a prediction of bone density. PATIENTS AND METHODS: Six pairs of human cadaveric radii were harvested. The mean donor age was 74 years. Standardized AP radiographs were taken of the radii. The outside diameter and the inside diameter of the cortical shell at the metaphyseal / diaphyseal junction were measured and their ratio was calculated. Dual-energy x-ray absorptiometry (DXA) was used to obtain the bone mineral density (BMD) of the distal parts of the radii. The correlation of the BMD values with these ratios was studied. RESULTS: The mean BMD was 0.559 (SD = 0.236) g / cm(2). The mean outside diameter/inside diameter ratio was 1.24 (SD = 0.013); the ratio significantly correlated with the total BMD (P = 0.001; R(2) = 0.710). In the BMD subregions, the correlation was also significant. CONCLUSIONS: The outside diameter/inside diameter ratio at the metaphyseal/diaphyseal junction of the distal radius on AP radiographs is suitable for use as a predictor of distal-radius bone density. Further studies should be performed, and clinical utility evaluated.

Evaluation of a polyaxial angle-stable volar plate in a distal radius C-fracture model--a biomechanical study.

INTRODUCTION: Polyaxial angle-stable plating is thought to be particularly beneficial in the management of complex intra-articular fractures of the distal radius. The purpose of the present study was to investigate whether the technique provides stability to match that of conventional (fixed-angle) angle-stable constructs. MATERIAL AND METHODS: In seven pairs of human cadaver radii, an Arbeitsgemeinschaft für Osteosynthese (AO) 23 C2.1 intra-articular fracture was created. One radius of each pair received a juxta-articular 2.4-mm locking compression plate (LCP) Volar Distal Radius Plate, whilst the contralateral one received a 2.4-mm Variable Angle Locking Compression Plate (LCP) Two-Column Volar Distal Radius Plate (both plates: Synthes, Oberdorf, Switzerland). Parameters tested were construct stiffness (static axial loading with 150 N), range of motion and secondary loss of reduction (dynamic 150 N axial loading over 5000 cycles). Stiffness and range of motion were measured both pre- and post-cycling. RESULTS: The polyaxial constructs were significantly stiffer, both before and after cyclic testing. However, the two-column plates showed a significant loss of stiffness during cyclic testing. The range of motion was significantly greater, both initially and at the end of cyclic testing, in the fixed-angle constructs. The conventional constructs had significantly greater secondary loss of reduction. CONCLUSION: The polyaxial two-column plate tested in this study provides a biomechanically sound construct for the management of intra-articular fractures of the distal radius.

A biomechanical comparison of a biodegradable volar locked plate with two titanium volar locked plates in a distal radius fracture model.

BACKGROUND: Volar plating is commonly used in the management of distal radius fractures; bioresorbable plates have attractive features. We compared a bioresorbable plate with a latest generation and an established locked titanium plate. METHODS: Twenty-four fresh-frozen radii (12 pairs) were assigned to three mean bone mineral density-matched groups of eight radii each. A standardized extraarticular distal radius fracture was created and plated using one implant type per group. Postplating stiffness and displacement were studied in a first axial-loading test (15 cycles at 250 N). Next, biodegradation was simulated by 4 weeks' immersion in phosphate-buffered saline, followed by a second axial test. Finally, the specimens underwent cyclic loading (2,400 cycles at 250 N). RESULTS: It is clear from the initial test that the LCP plate was significantly stiffer and displaced less than the bioresorbable plate. The outcome of the postimmersion tests is that one bioresorbable plate failed early on after 4 weeks' immersion, and the remaining bioresorbable plates and the T plates did not differ significantly. Cyclic tests conclude that the LCP plate was significantly superior to the other systems. One T plate and four of the bioresorbable plates failed, but none of the LCP plates failed. In the bioresorbable constructs, stability, time to failure, and bone mineral density were significantly correlated. CONCLUSIONS: The LCP plate was biomechanically superior and may be generally recommended for the volar plating of distal radius fractures. Except one plate failure, the bioresorbable plate was similar to the T plate in the quasi-static tests and should, therefore, be considered for clinical studies, with patient selection confined, initially, only to candidates with good bone stock quality.