Femoral defects in revision hip arthroplasty: a therapy-oriented classification.

INTRODUCTION: The complex field of femoral defects in revision hip arthroplasty displays a lack of standardized, intuitive pre- and intraoperative assessment. To address this issue, the femoral defect classification (FDC) is introduced to offer a reliable, reproducible and an intuitive classification system with a clear therapeutic guideline. MATERIALS AND METHODS: The FDC is based on the integrity of the main femoral segments which determine function and structural support. It focuses on the femoral neck, the metaphysis consisting of the greater and lesser trochanter, and the femoral diaphysis. The four main categories determine the location of the defect while subcategories a, b and c are being used to classify the extent of damage in each location. In total, 218 preoperative radiographs were retrospectively graded according to FDC and compared to intraoperatively encountered bone defects. To account for inter-rater and intra-rater agreement, 5 different observers evaluated 80 randomized cases at different points in time. RESULTS: A Cohens kappa of 0.832 ± 0.028 could be evaluated, accounting for excellent agreement between preoperative radiographs and intraoperative findings. To account for inter-rater reliability, 80 patients have been evaluated by 5 different observers. Testing for inter-rater reliability, a Fleiss Kappa of 0.688 could be evaluated falling into the good agreement range. When testing for intra-rater reliability, Cohens Kappa of each of the 5 raters has been analyzed and the mean was evaluated at 0.856 accounting for excellent agreement. CONCLUSION: The FDC is a reliable and reproducible classification system. It combines intuitive use and structured design and allows for consistent preoperative planning and intraoperative guidance. A therapeutic algorithm has been created according to current literature and expert opinion. Due to the combination of the FDC with the recently introduced Acetabular Defect Classification (ADC) a structured approach to the entire field of hip revision arthroplasty is now available.

Who profits from three-dimensional optics in endoscopic surgery? Analysis of manual tasks under two-dimensional/three-dimensional optic vision using a pelvic trainer model.

Background: In endoscopic operations, direct binocular view, tissue sensation and depth perception get lost. It is still unclear whether the novel three-dimensional (3D) high-definition (HD) cameras are able to compensate the limited senses and how this affects the skill set of users with different endoscopic experience. This study aimed first to evaluate if the 3D technology improves depth perception, precision and space orientation as compared to conventional two-dimensional (2D) HD technology. The second aim was to determine the 3D influence on participants with different endoscopic experience. Methods: A total of 24 participants of different experience levels performed three different tasks on a pelvic trainer using the same thoracoscopic unit in 2D and 3D modes. Results were statistically analysed using Student's t-test and Pearson's product-moment correlation. Results: Across all the participants, we found that 3D optic vision significantly reduced the needed time to perform a defined difficult task in comparison to 2D. This difference was less pronounced in participants with higher experience level. Participants with eyeglasses performed slower in both 2D and 3D in comparison to participants with normal vision. Only participants with normal vision could significantly improve their completion times with 3D optic vision. Conclusions: By testing the novel generation of 3D HD cameras, we could demonstrate that the 3D optic of these systems improves depth perception and space orientation for novices and experienced users and especially inexperienced users benefit from 3D optic.

Cartilage Regeneration with Cell-free Type 1 Collagen Matrix - Past, Present and Future (Part 1 - Clinical Aspects). / Knorpelregeneration mittels zellfreier Kollagen-Typ-I-Matrix ­ Vergangenheit, Gegenwart und Zukunft (Teil 1 ­ klinische Aspekte).

Cartilage regeneration with cell-free matrices has developed from matrix-associated autologous cartilage cell transplantation (MACT) over ten years ago. Adjustments to the legal framework and higher hurdles for cell therapy have led to the procedures being established as an independent alternative to MACT. These procedures, which can be classified as matrix-induced autologous cartilage regeneration (MACR), all rely on the chemotactic stimulus of a cross-linked matrix, which mostly consists of collagens. Given the example of a commercially available type I collagen hydrogel, the state of clinical experience with MACR shall be summarized and an outlook on the development of the method shall be provided. It has been demonstrated in the clinical case series summarized here over the past few years that the use of the matrix is not only safe but also yields good clinical-functional and MR-tomographic results for both small (~ 10 mm) and large (> 10 mm) focal cartilage lesions. Depending on the size of the defect, MACR with a collagen type I matrix plays an important role as an alternative treatment method, in direct competition with both: microfracture and MACT.

Cartilage Regeneration with a Cell-free Collagen Type 1 Matrix (Part 2 - Experimental Aspects). / Knorpelregeneration mittels zellfreier Kollagen-Typ-I-Matrix ­ Vergangenheit, Gegenwart und Zukunft (Teil 2 ­ experimentelle Aspekte).

Cartilage regeneration with cell-free matrices has developed from matrix-associated autologous cartilage cell transplantation (MACT) over ten years ago. Adjustments to the legal framework and higher hurdles for cell therapy have led to the procedures being established as an independent alternative to MACT. These procedures, which can be classified as matrix-induced autologous cartilage regeneration (MACR), all rely on the chemotactic stimulus of a cross-linked matrix, which mostly consists of collagens. Given the example of a commercially available type I collagen hydrogel, the physicochemical properties of such a matrix are explained and the available experimental data highlighted in more detail. The interaction between different cell types and the chemotactic properties of the collagen has been investigated extensively and, from a clinical point of view, today offers various reference points for a smart modification of the described method to further improve clinical outcomes. Since the origin of the cells in the ultimately formed repair tissue is still unrevealed, further investigations to clarify the exact mechanism are crucially needed.

Heterotopic Ossification - Complication or Chance? / Heterotope Ossifikation ­ Komplikation oder Chance?

So far, there has been no clear explanation of the pathophysiological relationships in the development of HO. There is little experimental data dealing with the post-traumatic inflammatory response in terms of a balance between the repair of damaged muscle cells and the opposite response in its development. There are numerous indications regarding possible predisposing factors, such as existence of surrounding tissue hypoxia or the function of pro-angiogenic (VEGF e.g.) and osteoinductive (BMP e.g.) factors. These different scientific approaches offer the opportunity to clinically intervene. In our opinion, early intervention seems to make the most sense in terms of effectiveness and recurrence of HO. An important pathomechanism seems to be chronic inflammation. Currently, non-steroidal anti-inflammatory drugs are the most commonly prescribed prophylaxis drugs. The effectiveness and efficacy of non-steroidal anti-inflammatory drugs is limited by the time-limited release and the side effect potential. Therefore, it is interesting to focus future research towards the cross-talks between immunosuppressive downregulation of the inflammatory response and its effect on the balance between muscle regeneration and the development of HO.

[Diagnosis of Patients with Painful Sacroiliac Joint Syndrome]. / Moderne Diagnostik und minimalinvasive Operationsmethoden bei Patienten mit schmerzhaftem Iliosakralgelenksyndrom.

Pain coming from the sacroiliac (SI) joints can explain up to 25% of all chronic low back pain. A careful differential diagnosis is required to avoid misdiagnosis of low back pain. In addition to historical findings, positive findings on physical examination maneuvers that stress the SI joint are a key component diagnosis. The SI joint is confirmed as a pain generator when intraarticular injection of local anaesthetics provides acute back pain relief. Minimally invasive SI joint fusion is clearly superior to invasive open surgical procedures, with decreased blood loss and tissue disruption, shorter procedure times and shorter hospital stays. Especially well documented are the results of minimally invasive SI joint fusion using iFuse Implant System®. The device's triangular profile, combined with a titanium plasma spray coating, ensures both an immediate and long-lasting joint stabilization.