Lehrstuhl für Orthopädie
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Sonstige beteiligte Institutionen
- IZKF Nachwuchsgruppe Geweberegeneration für muskuloskelettale Erkrankungen (7)
- Bernhard-Heine-Centrum für Bewegungsforschung (4)
- König-Ludwig-Haus Würzburg (3)
- Orthopädische Klinik und Poliklinik der Universität Würzburg (2)
- König Ludwig Haus Würzburg (1)
- König-Ludwig Haus (1)
- Lehrstuhl für Regeneration Muskuloskelettaler Gewebe (1)
- Muskuloskelettalen Zentrum Würzburg (MCW) (1)
- Muskuloskelettales Centrum Würzburg (MCW) (1)
- Orthopädische Klinik König-Ludwig-Haus (1)
- Orthopädische Klinik König-Ludwig-Haus Würzburg (1)
- Orthopädische Klinik und Poliklinik "König-Ludwig-Haus" der Uni Würzburg (1)
- Rhön-Klinikum Campus Bad Neustadt an der Saale, Klinik für Handchirurgie (1)
Background: A concern about kinematically aligned (KA) total knee arthroplasty (TKA) is that it relies on femoral components designed for mechanical alignment (MAd-FC) that could affect patellar tracking, in part, because of a trochlear groove orientation that is typically 6° from vertical. KA sets the femoral component coincident to the patient’s pre-arthritic distal and posterior femoral joint lines and restores the Q-angle, which varies widely. Relative to KA and the native knee, aligning the femoral component with MA changes most distal joint lines and Q-angles, and rotates the posterior joint line externally laterally covering the anterior femoral resection. Whether switching from a MAd- to a KAd-FC with a wider trochlear groove orientation of 20.5° from vertical results in radiographic measures known to promote patellar tracking is unknown. The primary aim was to determine whether a KAd-FC sets the trochlear groove lateral to the quadriceps line of force (QLF), better laterally covers the anterior femoral resection, and reduces lateral patella tilt relative to a MAd-FC. The secondary objective was to determine at six weeks whether the KAd-FC resulted in a higher complication rate, less knee extension and flexion, and lower clinical outcomes. Methods: Between April 2019 and July 2022, two surgeons performed sequential bilateral unrestricted caliper-verified KA TKA with manual instruments on thirty-six patients with a KAd- and MAd-FC in opposite knees. An observer measured the angle between a line best-fit to the deepest valley of the trochlea and a line representing the QLF that indicated the patient’s Q-angle. When the trochlear groove was lateral or medial relative to the QLF, the angle is denoted + or −, and the femoral component included or excluded the patient’s Q-angle, respectively. Software measured the lateral undercoverage of the anterior femoral resection on a Computed Tomography (CT) scan, and the patella tilt angle (PTA) on a skyline radiograph. Complications, knee extension and flexion measurements, Oxford Knee Score, KOOS Jr, and Forgotten Joint Score were recorded pre- and post-operatively (at 6 weeks). A paired Student’s T-test determined the difference between the KA TKAs with a KAd-FC and MAd-FC with a significance set at p < 0.05. Results: The final analysis included thirty-five patients. The 20.5° trochlear groove of the KAd-FC was lateral to the QLF in 100% (15 ± 3°) of TKAs, which was greater than the 69% (1 ± 3°) lateral to the QLF with the 6° trochlear groove of the MAd-FC (p < 0.001). The KAd-FC’s 2 ± 1.9 mm lateral undercoverage of the anterior femoral resection was less than the 4.4 ± 1.5 mm for the MAd-FC (p < 0.001). The PTA, complication rate, knee extension and flexion, and clinical outcome measures did not differ between component designs. Conclusions: The KA TKA with a KAd-FC resulted in a trochlear groove lateral to the QLF that included the Q-angle in all patients, and negligible lateral undercoverage of the anterior femoral resection. These newly described radiographic parameters could be helpful when investigating femoral components designed for KA with the intent of promoting patellofemoral kinematics.
Background
The key for successful delivery in minimally-invasive hip replacement lies in the exact knowledge about the surgical anatomy. The minimally-invasive direct anterior approach to the hip joint makes it necessary to clearly identify the tensor fasciae latae muscle in order to enter the Hueter interval without damaging the lateral femoral cutaneous nerve. However, due to the inherently restricted overview in minimally-invasive surgery, this can be difficult even for experienced surgeons.
Methods and Surgical Technique
In this technical note, we demonstrate for the first time how to use the tensor fasciae latae perforator as anatomical landmark to reliably identify the tensor fasciae latae muscle in orthopaedic surgery. Such perforators are used for flaps in plastic surgery as they are constant and can be found at the lateral third of the tensor fasciae latae muscle in a direct line from the anterior superior iliac spine.
Conclusion
As demonstrated in this article, a simple knowledge transfer between surgical disciplines can minimize the complication rate associated with minimally-invasive hip replacement.
Tissue-nonspecific alkaline phosphatase (TNAP) is a ubiquitously expressed enzyme that is best known for its role during mineralization processes in bones and skeleton. The enzyme metabolizes phosphate compounds like inorganic pyrophosphate and pyridoxal-5′-phosphate to provide, among others, inorganic phosphate for the mineralization and transportable vitamin B6 molecules. Patients with inherited loss of function mutations in the ALPL gene and consequently altered TNAP activity are suffering from the rare metabolic disease hypophosphatasia (HPP). This systemic disease is mainly characterized by impaired bone and dental mineralization but may also be accompanied by neurological symptoms, like anxiety disorders, seizures, and depression. HPP characteristically affects all ages and shows a wide range of clinical symptoms and disease severity, which results in the classification into different clinical subtypes. This review describes the molecular function of TNAP during the mineralization of bones and teeth, further discusses the current knowledge on the enzyme’s role in the nervous system and in sensory perception. An additional focus is set on the molecular role of TNAP in health and on functional observations reported in common laboratory vertebrate disease models, like rodents and zebrafish.
This review summarizes important information on the ectoenzyme tissue-nonspecific alkaline phosphatase (TNAP) and gives a brief insight into the symptoms, diagnostics, and treatment of the rare disease Hypophosphatasia (HPP), which is resulting from mutations in the TNAP encoding ALPL gene. We emphasize the role of TNAP beyond its well-known contribution to mineralization processes. Therefore, above all, the impact of the enzyme on central molecular processes in the nervous system and on inflammation is presented here.
With ageing, the loss of bone mass correlates with the expansion of adipose tissue in human bone marrow thus facilitating bone-related diseases like osteopenia and osteoporosis. The molecular mechanisms underlying these events are still largely unknown. Reduced osteogenesis and concurrently enhanced adipogenesis might not only occur due to the impairment of conventional osteogenic differentiation originating from mesenchymal stem cells (MSCs). Additionally, transdifferentiation of (pre-)osteoblasts into adipocytes could contribute to the fatty conversion. Therefore, the aim of the present study was to prove the existence of transdifferentiation between the adipogenic and osteogenic lineage and to elucidate molecular mechanisms underlying this phenomenon. At first, a cell culture system of primary human MSCs was established that allowed for differentiation into the adipogenic and osteogenic lineage and proved that the MSC-derived adipocytes and pre-osteoblasts were capable of transdifferentiation (reprogramming) from one into the other lineage. Thereby, lineage-specific markers were completely reversed after reprogramming of pre-osteoblasts into adipocytes. The osteogenic transdifferentiation of adipocytes was slightly less efficient since osteogenic markers were present but the adipogenic ones partly persisted. Hence, plasticity also reached into the differentiation pathways of both lineages and the better performance of adipogenic reprogramming further supported the assumption of its occurrence in vivo. The subsequent examination of gene expression changes by microarray analyses that compared transdifferentiated cells with conventionally differentiated ones revealed high numbers of reproducibly regulated genes shortly after initiation of adipogenic and osteogenic reprogramming. Thereof, many genes were correlated with metabolism, transcription, and signal transduction as FGF, IGF, and Wnt signalling, but only few of the established adipogenesis- and none of the osteogenesis-associated marker genes were detected within 24 h after initiation of transdifferentiation. To find possible key control factors of transdifferentiation amongst the huge amount of regulated genes, a novel bioinformatic scoring scheme was developed that ranked genes due to their potential relevance for reprogramming. Besides the reproducibility and level of their regulation, also the possible reciprocity between the adipogenic and osteogenic transdifferentiation pathway was taken into account. Fibroblast growth factor 1 (FGF1) that ranked as one of the leading candidates to govern reprogramming was proven to inhibit adipogenic differentiation as well as adipogenic transdifferentiation in our cell culture system. Further examination of the FGF signalling pathway and other highly ranked genes could help to better understand the age-related fatty degeneration at the molecular level and therefore provide target molecules for therapeutic modulation of the plasticity of both lineages in order to inhibit adipogenic degeneration and to enhance osteogenesis.
Alignment strategies for primary total knee arthroplasty (TKA) have changed significantly over time with a shift towards a more individualized alignment goal. At the same time, computer-assisted surgery (CAS) has gained interest for intraoperative control and accuracy in implant positioning and limb alignment. Despite the often discussed benefits and drawbacks of robotics and navigation for TKA, the routine use of these new devices on a day-to-day basis remains obscure. Therefore, nationwide hospital billing data based on the Operation Procedure Classification System (OPS) were retrieved from the Federal Statistical Office of Germany for the period from 2010 to 2021. OPS codes for primary total knee arthroplasty (OPS code: 5-822*) were further analyzed regarding the usage of computer navigation (additional OPS code: 5-988) or robotic devices (additional OPS code: 5-987). Gender and age at the time of surgery were also assessed. The results show a total of 2,226,559 primary TKAs were implanted between 2010 and 2021, of which 2,044,914 were performed conventionally (91.84% of all TKAs). A total of 170,276 TKAs were performed using navigation technique (7.65% of all TKAs) and another 11,369 TKAs were performed using robotics (0.51% of all TKAs). For the period from 2018 to 2021, a substantial increase in robot-assisted TKA (R-TKA) was observed, with an average increase rate of 84.74% per year, while the number of navigated TKAs declined (−3.67% per year). Computer-assisted surgery, and particularly robotics for TKA, are seeing growing popularity and stepwise translation into routine clinical use in Germany, with a steep increase rate of more than 80% per year since 2018. Nevertheless, the majority of TKAs are still performed using manual instrumentation, rendering conventional TKA the currently unchanged gold standard.
Ultra-high-resolution photon-counting detector CT arthrography of the ankle: a feasibility study
(2023)
This study was designed to investigate the image quality of ultra-high-resolution ankle arthrography employing a photon-counting detector CT. Bilateral arthrograms were acquired in four cadaveric specimens with full-dose (10 mGy) and low-dose (3 mGy) scan protocols. Three convolution kernels with different spatial frequencies were utilized for image reconstruction (ρ\(_{50}\); Br98: 39.0, Br84: 22.6, Br76: 16.5 lp/cm). Seven radiologists subjectively assessed the image quality regarding the depiction of bone, hyaline cartilage, and ligaments. An additional quantitative assessment comprised the measurement of noise and the computation of contrast-to-noise ratios (CNR). While an optimal depiction of bone tissue was achieved with the ultra-sharp Br98 kernel (S ≤ 0.043), the visualization of cartilage improved with lower modulation transfer functions at each dose level (p ≤ 0.014). The interrater reliability ranged from good to excellent for all assessed tissues (intraclass correlation coefficient ≥ 0.805). The noise levels in subcutaneous fat decreased with reduced spatial frequency (p < 0.001). Notably, the low-dose Br76 matched the CNR of the full-dose Br84 (p 0.999) and superseded Br98 (p < 0.001) in all tissues. Based on the reported results, a photon-counting detector CT arthrography of the ankle with an ultra-high-resolution collimation offers stellar image quality and tissue assessability, improving the evaluation of miniscule anatomical structures. While bone depiction was superior in combination with an ultra-sharp convolution kernel, soft tissue evaluation benefited from employing a lower spatial frequency.
Background and purpose - Due to the relative lack of reports on the medium- to long-term clinical and radiographic results of modular femoral cementless revision, we conducted this study to evaluate the medium- to long-term results of uncemented femoral stem revisions using the modular MRP-TITAN stem with distal diaphyseal fixation in a consecutive patient series.
Patients and methods - We retrospectively analyzed 163 femoral stem revisions performed between 1993 and 2001 with a mean follow-up of 10 (5-16) years. Clinical assessment included the Harris hip score (HHS) with reference to comorbidities and femoral defect sizes classified by Charnley and Paprosky. Intraoperative and postoperative complications were analyzed and the failure rate of the MRP stem for any reason was examined.
Results - Mean HHS improved up to the last follow-up (37 (SD 24) vs. 79 (SD 19); p < 0.001). 99 cases (61%) had extensive bone defects (Paprosky IIB-III). Radiographic evaluation showed stable stem anchorage in 151 cases (93%) at the last follow-up. 10 implants (6%) failed for various reasons. Neither a breakage of a stem nor loosening of the morse taper junction was recorded. Kaplan-Meier survival analysis revealed a 10-year survival probability of 97% (95% CI: 95-100).
Interpretation - This is one of the largest medium- to longterm analyses of cementless modular revision stems with distal diaphyseal anchorage. The modular MRP-TITAN was reliable, with a Kaplan-Meier survival probability of 97% at 10 years.
Knochensialoprotein (BSP) ist ein Protein der extrazellulären Matrix im Knochen und mineralisierten Geweben, wird aber auch von verschiedenen Tumorzellen exprimiert (Bellahcene et al., 1994, 1997, 1998). Dies ist assoziiert mit einer schlechten Prognose und einem erhöhten Risiko für eine spätere Entwicklung von Knochenmetastasen. Diel et al. (1999) konnte zeigen, dass ein erhöhter Serum-BSP-Wert bei Patientinnen mit Mammakarzinom zu einem gehäuften Auftreten von Knochenmetastasen im Laufe der Erkrankung führt. BSP scheint ein Marker für die Entstehung von Knochenmetastasen zu sein. In der Literatur ist ein Antikörper beschrieben, der ein Epitop des BSP erkennt, welches im BSP aus Tumorzellen nicht glykosyliert ist, im BSP aus mineralisiertem Gewebe allerdings schon (Armbruster et al., 2009). Im Tiermodell konnte gezeigt werden, dass Knochenmetastasen verhindert werden können bei gleichzeitiger Gabe von Tumorzellen und Antikörpern gegen BSP beziehungsweise, dass bei vorhandenen Knochenmetastasen eine Behandlung der Tiere mit einem Anti-BSP-Antikörper die Metastasen zurückbildet (Bäuerle et al., 2005, 2006). In der aktuellen Arbeit wird die Expression von BSP an menschlichem Gewebe von Knochenmetastasen mit unterschiedlichen Primärtumoren mittels Immunhistochemie untersucht. Insgesamt wurden 35 Fälle von Knochenmetastasen mit Primärtumor eines Mammakarzinoms untersucht, wobei 22,9% eine BSP Expression aufweisen, davon 5,7% eine starke. Knochenmetastasen mit dem Primärtumor Prostatakarzinom sind mit 8 Fällen repräsentiert, wobei 75% positiv für BSP sind, davon 25% stark positiv. Die einzelnen Fälle zeigen eine starke BSP Expression im Stroma und eine schwache BSP Expression der Tumorzellen. Diese Ergebnisse des Antikörpers gegen normal glykosyliertes BSP wurden verglichen mit dem Antikörper gegen nicht glykosyliertes BSP. Der Nachweis von BSP in Tumorzellen zeigt dasselbe Ergebnis, BSP im Stroma wird durch den Antikörper gegen nicht- glykosyliertes BSP intensiver dargestellt. Daraus lässt sich folgern, dass der Antikörper gegen nicht- glykosyliertes BSP nicht spezifisch für die Isoform des BSP aus Tumorzellen ist, sondern gleichermaßen in der Routinediagnostik von BSP eingesetzt werden kann. Die Untersuchung könnte sogar darauf hinweisen, dass dieser Antikörper die nicht- glykosylierte Isoform im Stroma erkennt und damit bei Untersuchung des Stromas die bessere Alternative darstellt.
Patellaluxationen sind eine vor allem bei jungen, aktiven Patienten häufige Verletzung komplexer Ätiologie. Die Rekonstruktion des medialen patellofemoralen Ligaments (MPFL) ist die aktuell etablierte Operationstechnik bei strecknaher patellofemoraler Instabilität, zu der in der Literatur eine Vielzahl an patellaren Fixationstechniken des autologen Sehnentransplantates beschrieben werden.
In dieser Studie wurden 71 Patienten 5 Jahre nach Rekonstruktion des MPFLs mit patellarer Fixation in Weichteiltechnik nachuntersucht und die klinischen Ergebnisse der Operationsmethode und die Zufriedenheit der Patienten ermittelt.
Dafür wurde die Reluxationsrate ermittelt und die Funktion der Kniegelenke im Alltag mithilfe des Kujala- und des Lysholm-Fragebogens, das Aktivitätsniveau der Patienten mit der Tegner-Aktivitätsskala erfasst. Im Rahmen einer Nachuntersuchung wurden die Beweglichkeit des Kniegelenks und die Stabilität der Kniescheibe klinisch untersucht. Die Ergebnisse wurden unter Berücksichtigung klinischer und radiologischer Risikofaktoren ausgewertet.
Die Studie ergab eine Reluxationsrate von 5,6% und ist somit vergleichbar mit der Rate anderer in der Literatur beschriebener Techniken. Die Ergebnisse der klinischen Untersuchung ergaben eine stabile ligamentäre Führung der Kniescheibe bei insgesamt guter Beweglichkeit der Kniegelenke, die Auswertung der Fragebögen zeigten signifikante Verbesserungen der Funktion der operierten Kniegelenke im Alltag bei unverändertem Aktivitätsniveau.
Im Ergebnis kann durch die vorliegende Studie belegt werden, dass durch die Rekonstruktion des MPFL mit weichteiliger patellarer Fixation langfristig gute Ergebnisse bei einer niedrigen Komplikationsrate erzielt werden können. Allerdings erhöht das Zusammentreffen verschiedener Pathologien wie eine Patella alta mit einer ausgeprägten Dysplasie der Trochlea das Risiko für eine persistierende Instabilität und eine erneute Luxation.