Andreas Lenich

Standardised cement augmentation of the PFNA using a perforated blade: A new technique and preliminary clinical results. A prospective multicentre trial.

Pertrochanteric fractures are a rising major health-care problem in the elderly and their operative stabilisation techniques are still under discussion. Furthermore, complications like cut-out are reported to be high and implant failure often is associated with poor bone quality. The PFNA(®) with perforated blade offers a possibility for standardised cement augmentation using a polymethylmethacrylate (PMMA) cement which is injected through the perforated blade to enlarge the load-bearing surface and to diminish the stresses on the trabecular bone. The current prospective multicentre study was undertaken to evaluate the technical performance and the early clinical results of this new device. In nine European clinics, 59 patients (45 female, mean age 84.5 years) suffering from an osteoporotic pertrochanteric fracture (Arbeitsgemeinschaft für Osteosynthesefragen, AO-31) were treated with the augmented PFNA(®). Primary objectives were assessment of operative and postoperative complications, whereas activities of daily living, pain, mobility and radiologic parameters, such as cement distribution around the blade and the cortical thickness index, were secondary objectives. The mean follow-up time was 4 months where we observed callus healing in all cases. The surgical complication rate was 3.4% with no complication related to the cement augmentation. More than one-half of the patients reached their prefracture mobility level within the study period. A mean volume of 4.2ml of cement was injected. We did not find any cut-out, cut through, unexpected blade migration, implant loosening or implant breakage within the study period. Our findings lead us to conclude that the standardised cement augmentation using the perforated blade for pertrochanteric fracture fixation enhances the implant anchorage within the head-neck fragment and leads to good functional results.

Biomechanical effect of bone cement augmentation on rotational stability and pull-out strength of the Proximal Femur Nail Antirotation™

INTRODUCTION After surgical treatment of osteoporotic hip fractures, complications such as implant cut-out are reported to be high and implant failure often is associated with poor bone quality. As augmentation is reported to enhance implant anchorage, the aim of our study was to investigate the effect of bone cement augmentation on the rotational stability and the pull-out resistance of the Proximal Femur Nail Antirotation™ (PFNa) blade. MATERIALS AND METHODS A total of 18 fresh-frozen femoral heads (mean age 68 years, standard deviation (SD) 8.2) were scanned with quantitative computed tomography (qCT) for bone mineral density (BMD) measurements and instrumented with a PFNa blade. Nine specimens were augmented with a mean volume of 4.4 ml Traumacem V+. After cement consolidation, the blade was rotated for 60° for the rotational test. Subsequently, the blade was extracted from the specimens. Force, torque, displacement and angle were recorded constantly. RESULTS In the rotational test, the mean maximum torque in the augmented group (17.2 Nm, SD 5.0) was significantly higher (p=0.017) than in the non-augmented group (11.7 Nm, SD 3.5). The pull-out test also yielded a significant difference (p=0.047) between the augmented (maximum pullout force: 2315.2N, SD 1060.6) and the non-augmented group (1180.4N, SD 1171.4). DISCUSSION Augmentation of femoral heads yielded a significantly superior rotational stability, as well as an enhanced pull-out resistance, compared to the non-augmented state. However, the higher the BMD of the specimens, the lower was the effect of augmentation on the rotational stability. Therefore, augmentation can be a good clinical tool to enhance implant anchorage in osteoporotic bone.

Biomechanical Comparison of Intramedullary Cortical Button Fixation and Interference Screw Technique for Subpectoral Biceps Tenodesis

PURPOSE The purpose of this study was to biomechanically evaluate a new technique of intramedullary cortical button fixation for subpectoral biceps tenodesis and to compare it with the interference screw technique. METHODS We compared intramedullary unicortical button fixation (BicepsButton; Arthrex, Naples, FL) with interference screw fixation (Bio-Tenodesis screw; Arthrex) for subpectoral biceps tenodesis using 10 pairs of human cadaveric shoulders and ovine superficial digital flexor tendons. After computed tomography analysis, the specimens were mounted in a testing machine. Cyclic loading was performed (preload, 5 N; 5 to 70 N at 1.5 Hz for 500 cycles), recording the displacement of the tendon. Load to failure and stiffness were subsequently evaluated with a load-to-failure test (1 mm/s). RESULTS Cyclic loading showed a displacement of 11.3 ± 2.8 mm for intramedullary cortical button fixation and 9 ± 1.7 mm for interference screw fixation (P = .112). All specimens within the cortical button group passed the cyclic loading test, whereas 3 of 10 specimens within the interference screw group failed by tendon slippage at the screw-tendon-bone interface after a mean of 252 cycles (P = .221). Load-to-failure testing showed a mean load to failure of 218.8 ± 40 N and stiffness of 27.2 ± 7.2 N/mm for the intramedullary cortical button technique. For the interference screw, the mean load to failure was 212.1 ± 28.3 N (P = .625) and stiffness was 40.4 ± 13 N/mm (P = .056). CONCLUSIONS We could not find any major differences in load to failure when comparing the tested techniques for subpectoral biceps tenodesis. Intramedullary cortical button fixation showed no failure during cyclic testing. However, we found a 30% failure rate (3 of 10) for the interference screw fixation. CLINICAL RELEVANCE Intramedullary cortical button fixation provides an alternative technique for subpectoral biceps tenodesis with comparable and, during cyclic loading, even superior biomechanical properties to interference screw fixation.

Femorale Osteotomien bei patellofemoraler Instabilität

ZusammenfassungAchsen- und Torsionsfehlstellungen des Femurs sind als Ursachen von Patellainstabilität und patellofemoralem Schmerz anerkannt. Die zugrunde liegende Biomechanik wird erklärt und die radiologische Diagnostik mittels Computertomographie (CT) beschreiben. Die Technik der biplanaren varisierenden bzw. derotierenden distalen Femurosteotomie wird im Detail beschrieben und wir berichten über die bisherigen Behandlungsverläufe. In der Literatur findet dieses Vorgehen als Teilaspekt multimodaler Behandlungskonzepte mit guten bis sehr guten klinischen Ergebnissen Erwähnung.AbstractAxis and torsion malalignment of the femur has been widely recognized as a primary reason for patellofemoral instability and pain. In this article we explain the current concepts of biomechanics and describe the radiological findings in computed tomography (CT) examination. We describe the technique of a biplanar varus and/or external rotation distal femoral osteotomy in detail. Existing clinical studies describe this technique as part of a multimodal treatment concept with good to excellent results. We present our current technique and clinical results.

Avulsion of the anterior medial meniscus root: case report and surgical technique

AbstractInjuries of the meniscus roots have become increasingly recognised as a serious pathology of the knee joint. However, the current available literature focuses primarily on posterior meniscus root tears. In this article, a case with an isolated avulsion of the anterior medial meniscus root is presented, and a new arthroscopic technique to treat this type of injury is described. The anterior horn of the medial meniscus was sutured with a double-looped nonabsorbable suture and reattached to the tibial plateau using a knotless suture anchor. This technique may also be useful to treat avulsion injuries of the anterolateral or posteromedial meniscus root, and symptomatic subluxation of the medial meniscus in case of a variant insertion anatomy with an absent attachment of the anterior horn of the medial meniscus to the tibial plateau. Level of evidence V.

Femoral osteotomy for patellofemoral instability

ZusammenfassungAchsen- und Torsionsfehlstellungen des Femurs sind als Ursachen von Patellainstabilität und patellofemoralem Schmerz anerkannt. Die zugrunde liegende Biomechanik wird erklärt und die radiologische Diagnostik mittels Computertomographie (CT) beschreiben. Die Technik der biplanaren varisierenden bzw. derotierenden distalen Femurosteotomie wird im Detail beschrieben und wir berichten über die bisherigen Behandlungsverläufe. In der Literatur findet dieses Vorgehen als Teilaspekt multimodaler Behandlungskonzepte mit guten bis sehr guten klinischen Ergebnissen Erwähnung.AbstractAxis and torsion malalignment of the femur has been widely recognized as a primary reason for patellofemoral instability and pain. In this article we explain the current concepts of biomechanics and describe the radiological findings in computed tomography (CT) examination. We describe the technique of a biplanar varus and/or external rotation distal femoral osteotomy in detail. Existing clinical studies describe this technique as part of a multimodal treatment concept with good to excellent results. We present our current technique and clinical results.

Worauf muss neben der Reposition geachtet werden

Obwohl das Ellenbogengelenk äußerst stabil ist, ist die Ellen-bogenluxation die zweithäufigste, bei Kindern die häufigste Gelenksverletzung. Die Entscheidung über eine konservative bzw. operative Therapie richtet sich danach, in welchem Ausmaß die so genannten primären und sekundären Ellenbogenstabilisatoren verletzt sind. Wichtig für das Endergebnis sind jedenfalls eine frühfunktionelle Bewegungstherapie und ggf. der Einsatz von Bewegungsorthesen.

Ellenbogenluxationsverletzungen beim Trendsport Bouldern

Bouldering is a new trend sport which has become popular in recent years. From April 2011 to June 2012 a total of 5 patients with elbow dislocations from bouldering were admitted to our level 1 trauma center. The injuries varied from simple elbow dislocations to complex fracture dislocations. Elbow dislocations occurred during falling backwards when patients tried to protect themselves by retroversion of both arms. In all cases the falling height was less than 4 meters. The bouldering injury pattern, the diagnostic and therapeutic management as well as the rehabilitation program are described in detail in this article. To the best of our knowledge this is the first report on the special danger of bouldering for complex elbow injuries.

Virtual morphological comparison of three intramedullary nailing systems for the treatment of proximal humeral fractures

Proximal humerus fractures treated with intramedullary nails show good results. However, the correct anatomical reconstruction of four-part fractures is demanding especially when using intramedullary nails. We therefore compared different intramedullary nail designs for the proximal humerus in a virtual morphological manner. Three commercially available nailing systems where virtually implanted in virtually generated reproducible four-part fractures of 25 digitised humeri. The objective of this study was to quantify and characterise the anatomical position of the proximal screws in the most vulnerable case of a four-part fracture. Taking into account a minimum distance of 5mm between the screw head and the fracture line, osteosynthesis was possible in 54 out of 75 cases. Difficulties placing the proximal screws could be observed at the localisation of the lower lesser tubercle or/and at the sulcus intertubercularis. This morphological analysis could be the basis for choosing the most sufficient implant intra operatively or even improving the nail design.

Novel technique for sternoclavicular joint reconstruction using a gracilis tendon autograft

Abstract Surgical treatment of sternoclavicular joint instability can be challenging and carries the inherent risk of damaging vital structures if the posterior capsule is violated during surgery. In the current manuscript, a novel and easy technique for open reduction and tendon graft stabilization of the unstable sternoclavicular joint is presented. Analogous to other techniques, the graft is passed through drill holes in a figure-of-eight configuration. However, for this technique, the drill holes are placed in oblique direction from the anterior cortex towards the articular surface of the sternum, respectively the medial clavicle. By doing so, graft reconstruction is achieved without any need for retrosternal dissection and mobilization of the posterior capsule, thus minimizing the risk of severe intraoperative complications. Level of evidence V.