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Background:
To prevent bone loss in hip arthroplasty, several short stem systems have been developed, including the Mayo conservative hip system. While there is a plethora of data confirming inherent advantages of these systems, only little is known about potential complications, especially when surgeons start to use these systems.
Methods:
In this study, we present a retrospective analysis of the patients’ outcome, complications and the complication management of the first 41 Mayo conservative hips performed in 37 patients. For this reason, functional scores, radiographic analyses, peri- and postoperative complications were assessed at an average follow-up of 35 months.
Results:
The overall HHS improved from 61.2 pre-operatively to 85.6 post-operatively. The German Extra Short Musculoskeletal Function Assessment Questionnaire (XSFMA-D) improved from 30.3 pre-operatively to 12.2 post-operatively. The most common complication was an intraoperative non-displaced fracture of the proximal femur observed in 5 cases (12.1%). Diabetes, higher BMI and older ages were shown to be risk factors for these intra-operative periprosthetic fractures (p < 0.01). Radiographic analysis revealed a good offset reconstruction in all cases.
Conclusion:
In our series, a high complication rate with 12.1% of non-displaced proximal femoral fractures was observed using the Mayo conservative hip. This may be attributed to the flat learning curve of the system or the inherent patient characteristics of the presented cohort."
Background
Radiographic imaging is an important tool to assess osteoarthritis (OA). Lateral compartment osteoarthritis (valgus OA) usually starts with cartilage degeneration along the posterior aspect of the lateral femoral condyle. There is evidence that the posterior-anterior (PA)-flexed view is more sensitive when diagnosing early stages of valgus OA compared to the anterior-posterior (AP) view. The current paper analyzes the value of the PA-flexed view for patients scheduled for total knee arthroplasty (TKA).
Methods
Radiographs of 134 valgus knees were assessed prior to TKA. The minimal joint space width (minJSW) was measured on AP and PA-flexed views. The extent of mechanical deformity was measured on hip to ankle standing films.
Results
49 (36.6%) AP views showed Kellgren and Lawrence (K/L)-grade 4 osteoarthritis in the lateral compartment, 82 (63.4%) showed grade 3 or less. The PA-flexed view resulted in an increased K/L-grading to grade 4 for 53 knees (62.4%) that were considered grade 3 or less on standard AP-radiographs. There was a significant differences between lateral minJSW on AP and PA-flexed view for patients with up to 10 degrees of mechanical valgus deformity (p < 0.001), as well as 11 to 15 degrees of mechanical deformity (p = 0.021). Only knees with severe deformity of more than 15 degrees did not show a difference in minJSW between PA-flexed view and AP view (p = 0.345).
Conclusions
The PA-flexed view is superior to the standard AP view in quantifying the extent of valgus OA in patients with zero to fifteen degrees of valgus deformity. It is recommended for the initial assessment of patients with valgus osteoarthritis and better documents the extent of osteoarthritis prior to TKA.
Background
Joint aspiration with analysis of synovial fluid white blood cell count (WBC) and microbiological culture is a widely established aspect in the diagnosis of shoulder joint infections (SJI). In case of a two stage revision for SJI, joint aspiration before re−/implantation of a total shoulder arthroplasty (TSA) was used to rule out persistent infection for years but its value is under debate. Shoulder specific data on all aspects is rare. The current study aims to answer the following research questions: Does joint aspiration have an insufficient predictive value in the diagnosis of SJI in (1) initial workup and (2) before definite arthroplasty with polymethylmethacrylate (PMMA)-Spacer in place?
Methods
This retrospective evaluation investigates 35 patients that were treated for SJI with a two staged implantation of a TSA after debridement and implantation of an PMMA-Spacer. Joint aspirations were performed preoperatively (PA) and before re−/implantation of the prosthesis while spacer was in place (interstage aspiration, IA). Samples were taken for microbiological culture and analysis of WBC. Sensitivity and specificity were calculated with reference to intraoperative microbiological samples. Receiver Operating Characteristic (ROC), Area-Under-Curve analysis (AUC) and calculation of the Youden index were performed to find optimum cut-off for WBC.
Results
The sensitivity of microbiological cultures from PA was 58.3% and the specificity was 88.9%. The mean WBC was 27,800 leucocytes/mm3 (range 400-96,300). The maximum Youden index (0.857) was a cut-off of 2600 leucocytes/mm3 with a sensitivity of 85.7% and a specificity of 100.0%. The sensitivity and specificity of IA were 0.0% and 88.5%, respectively.
Conclusions
Preoperative aspiration is likely to miss Cutibacteria spp. and CoNS and cannot rule out infection for sure. However, we recommend it for its advantages of targeted antibiotic therapy in case of germ identification. Empiric antibiotic therapy should cover Cutibacteria and CoNS even if aspiration showed negative microbiological cultures. In contrast, the diagnostic value of interstage aspiration does not qualify for its routine use.
Primary osteoporosis is an age-related disease characterized by an imbalance in bone homeostasis. While the resorptive aspect of the disease has been studied intensely, less is known about the anabolic part of the syndrome or presumptive deficiencies in bone regeneration. Multipotent mesenchymal stem cells (MSC) are the primary source of osteogenic regeneration. In the present study we aimed to unravel whether MSC biology is directly involved in the pathophysiology of the disease and therefore performed microarray analyses of hMSC of elderly patients (79-94 years old) suffering from osteoporosis (hMSC-OP). In comparison to age-matched controls we detected profound changes in the transcriptome in hMSC-OP, e.g. enhanced mRNA expression of known osteoporosis-associated genes (LRP5, RUNX2, COL1A1) and of genes involved in osteoclastogenesis (CSF1, PTH1R), but most notably of genes coding for inhibitors of WNT and BMP signaling, such as Sclerostin and MAB21L2. These candidate genes indicate intrinsic deficiencies in self-renewal and differentiation potential in osteoporotic stem cells. We also compared both hMSC-OP and non-osteoporotic hMSC-old of elderly donors to hMSC of similar to 30 years younger donors and found that the transcriptional changes acquired between the sixth and the ninth decade of life differed widely between osteoporotic and non-osteoporotic stem cells. In addition, we compared the osteoporotic transcriptome to long term-cultivated, senescent hMSC and detected some signs for pre-senescence in hMSC-OP. Our results suggest that in primary osteoporosis the transcriptomes of hMSC populations show distinct signatures and little overlap with non-osteoporotic aging, although we detected some hints for senescence-associated changes. While there are remarkable inter-individual variations as expected for polygenetic diseases, we could identify many susceptibility genes for osteoporosis known from genetic studies. We also found new candidates, e.g. MAB21L2, a novel repressor of BMP-induced transcription. Such transcriptional changes may reflect epigenetic changes, which are part of a specific osteoporosis-associated aging process.
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.