[Atypical femoral fracture : Pitfalls in surgical treatment]. / Atypische Femurfraktur : Fallstricke bei der chirurgischen Versorgung.

Atypical femoral fractures are a very rare complication after treatment with bisphosphonates. This case report describes the diagnostic criteria and some particularities of the surgical treatment. Atypical femoral fractures are typically stabilized with intramedullary nails but some pitfalls in surgical treatment, e.g. the choice of implant, have to be considered. Basically, these fractures can be treated using conventional intramedullary nails, which, however, must be used by being adapted depending on the morphology of the femur. The fact that atypical femoral fractures can occur under bisphosphonate treatment should in no way influence the indications for starting anti-osteoporotic treatment.

Progress of instability in fragility fractures of the pelvis: An observational study.

Fragility fractures of the pelvis (FFP) are an increasing entity among elderly persons. Characteristics are different from high-energy pelvic trauma. Little is known about the natural course of FFP in conservative and after operative treatment. MATERIALS AND METHODS: Medical charts and radiologic data of 148 patients with an FFP, who were admitted in a 3-year period, were analysed retrospectively. Incidence and characteristics of fracture progression (FP) were noted. RESULTS: Patients presenting early after a traumatic event had more often non-displaced fractures, fractures with lower FFP Type classification and were more frequently treated conservatively. FP was observed in 21 cases (14.2%), twenty times after conservative and once after operative treatment. FP under conservative treatment occurred in female patients only. Patients with FP were younger than patients without. FP occurred in all fracture types, most frequently in FFP Type I. A second CT scan was positive for FP in 39.2% of patients with prolonged pain or restricted mobility. CONCLUSION: FP is a real phenomenon, occurring in a minority of FFP patients. Female patients are at highest risk. Repeated CT scan is positive in nearly 40% of patients with continuing pain or restricted mobility. Operative treatment is a good preventive measure of FP as FP does only exceptionally occur after operative fixation of FFP.

Reconstruction of complex radial head fractures using fine-threaded K-wires : clinical outcome and remaining instability.

Radial head replacement or ORIF are established treatment options for Mason type-III and type-IV fractures. The aim of this study was to provide results for reconstruction of these complex fractures using fine-threaded K-wires. We present results after reconstruction of 15 Mason type-III and 8 Mason type-IV fractures. Parameters used to describe the functional outcome were pain level, range of motion, and clinical scores. To estimate the elbow stability we performed ultrasound examinations under valgus/varus stress. All radial heads could be reconstructed. The average resting pain level was 0.9 of 10. The average ROM for extension/flexion was 134°, average forearm rotation was 159°. For the whole patient collective the mean MEPS was 86.5 points and the mean QuickDASH was 16.8 points with no significant difference for both groups. We can recommend ORIF with fine-threaded K-wires for Mason type-III and type-IV fractures of the radial head. Ligamentous injuries can be addressed successfully with external fixation.

Reconstruction of Monteggia-like proximal ulna fractures using different fixation devices: A biomechanical study.

BACKGROUND: Comminuted proximal ulna fractures are rare and reconstruction of these fractures is discussed controversially. The aim of this study was to test three currently available plate devices in a standardized comminuted four-part fracture model created in proximal ulna sawbones. MATERIAL AND METHODS: A standardized four-part fracture of the proximal ulna was created in 80 sawbones. Reconstruction was performed by five experienced test surgeons according to a standardized reconstruction protocol. Each surgeon reconstructed 4 fractures with a 3.5mm eight-hole reconstruction plate, 4 fractures with seven-hole third-tubular double plates and 4 fractures with a 3.5mm anatomical seven-hole locked angle proximal ulna plate. 4 more fractures were reconstructed with simple K-wires as a reference construct for further experiments. Outcome measurements were time for reconstruction, quality of reconstruction and stability of the reconstruction. Stability testing was done in 90° and 30° flexion of the elbow. Testing in 30° flexion was done to test the anteroposterior stability regarding the fixed coronoid process. RESULTS: Time for reconstruction was significantly less for K-wire fixation than for the plate devices. Time for reconstruction plating and locked angle plating was significantly lower than for double plating (p<0.005). Quality of reduction did not differ between the three plate systems (p<0.05). K-wire fixation showed the best quality of reduction (p<0.005). In 90° of elbow flexion the anatomic locked angle olecranon plate showed a significantly higher stability compared to the other devices. Furthermore the tubular double plating was significantly more stable than reconstruction plating or K-wire fixation (p<0.05). In anteroposterior loading at 30°, the stability did not differ between the 4 different fixation techniques (p>0.05). For all devices the testing in 30° flexion showed a significantly higher rigidity compared to 90° flexion. CONCLUSION: The locked angle plate system showed the highest stability in 90° of elbow flexion. Each implant was more stable in 30° flexion than in 90° flexion. Testing of the anterior stability of the elbow did not show any differences between the different implants. Because of the superior stability of this device, we conclude that locked angle plating should be preferred for reconstruction of monteggia like complex proximal ulna fractures.

[Supramacroparticulate polyethylene in inflammation of synovial-like interface membranes: Characterization and suggested nomenclature]. / Supramakropartikuläres Polyethylen bei Entzündungen periprothetischer Membranen: Charakterisierung und Nomenklaturvorschlag.

BACKGROUND: The identification of particles of prosthesis material components in the histopathological diagnosis of synovialitis is of great importance in the evaluation of implant failure. MATERIALS AND METHODS: In histopathological particle algorithms, polyethylene (PE) particles with a maximum length of less than 100 µm are designated with the term macroparticles; however, a systematic investigation and characterization are lacking. RESULTS: In SLIM knee specimens (n = 24) a minimum value of 210 µm and a maximum value of 2100 µm were measured; the mathematical mean length varied between 235 µm and 1416 µm. In SLIM hip specimens (n = 11) the minimum value was 290 µm and the maximum value was 1806 µm; the mean length varied between 353 and 1726 µm. Because of this conspicuous size, and to distinguish from PE macroparticles, the designation PE supra-macroparticulate is suggested. This new terminology acknowledges the fact that these PE particles are visible under magnification (e.g., × 12.5) and also macroscopically. The particles were also indirectly proven as there were completely separate and optically clear, column-shaped cavities corresponding to the shape of the PE particles (PE vacuoles). The life of the prosthesis is highly variable at between 12 and 300 months. In all cases loosening of the prosthesis, misalignment of the PE components, and/or damage to the PE inlay occurred. CONCLUSION: The cause and existence of these supra-macroparticulate PE particles (more than 100 µm) is still unclear. A mechanical malfunction seems probable and should be discussed. In prostheses with short lives the proof of supra-macroparticulate PE in SLIM could be a sign of an early mechanical problem. In the wider histopathological particle algorithm supra-macroparticulate PE was considered to fall in the category of macroparticles and should be considered in the histopathological diagnosis of implant failure.

Presentation of the vascular supply of the proximal ulna using a sequential plastination technique.

PURPOSE: The purpose of this study was to demonstrate the peri- and intraosseous vascular supply of the proximal ulna. METHODS: Eleven fresh human cadaveric elbows were sequentially plastinated beginning with arterial injection, followed by block and secondary slice plastination of the whole elbow. With this technique, we obtained completely transparent cadaveric slices in which the peri- and intraosseous vascular architecture could be studied. RESULTS: Proximal ulna vascularization is due to an arterial network: a superior and inferior collateral ulnar artery and the profunda brachial artery climbing to the olecranon from proximal. An anterior artery and a posterior recurrent artery climb up distally to the medial parts of the ulna and an interosseous recurrent artery is responsible for the lateral and posterolateral proximal part of the ulna. The intraosseous vascularization is due to directly penetrating branches out of the posterior recurrent ulnar artery and a vascular plexus at the olecranon tip. In addition, we saw a major distal bone penetration branch coming from the recurrent posterior artery, climbing intraosseously without junction to the proximal penetrating branches. CONCLUSION: The peri- and intraosseous vascularization of the proximal ulna was shown. A transitional zone of the intraosseous vascularization of the proximal ulna was detected.