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Introduction: High tibial medial open-wedge valgus osteotomy (HTO) is a well-established procedure for unicompartimental medial osteoarthritis of the young and active patient. However, the influence of cartilage defects of the lateral compartment on the total outcome remains obscure. Methods: From 2005 to 2012, a total of 63 patients underwent HTO for medial osteoarthritis of the knee at a single university orthopaedic center. Baseline data as well as intraoperative findings, including the grade and location of cartilage lesions, were evaluated retrospectively. Two groups were formed regarding the integrity of the lateral tibiofemoral compartment as measured by the Outerbridge score (group A: no lateral cartilage defects, group B: mild to moderate lateral cartilage defects). Functional outcome was assessed using the Knee and Osteoarthritis Outcome Score (KOOS), including its five subscores. Results: Comparing pre- and postoperative data, we identified an overall benefit of the HTO procedure as measured by the KOOS. Group A (no lateral cartilage defects) showed an increase in all five KOOS subscores (p = 0.00–0.01), whereas for group B (mild to moderate lateral cartilage defects), only two KOOS subscores revealed a significant increase (p = 0.03–0.04). There was also a statistically significant difference in the total KOOS score with higher values for group A at the postoperative visit. Cartilage defects with a higher Outerbridge score were associated with lower postoperative KOOS subscores. Discussion: Mild to moderate cartilage defects of the lateral compartment humble the total outcome after HTO procedure. Thus, indication for HTO should be made very carefully if any degree of lateral cartilage degeneration is present.

Vitamin D is crucial for ideal bone health and good muscle function, both essential requirements for successful joint arthroplasty. Hence, vitamin D deficiency has recently been identified as a predictor of poorer outcomes in patients scheduled to undergo total joint arthroplasty (TJA). Moreover, there is ample evidence today that vitamin D deficiency is associated with periprosthetic joint infection. Yet, vitamin D deficiency seems to be frequent in patients who are scheduled to undergo TJA. However, the prevalence of hypovitaminosis D in patients who require revision arthroplasty (rTJA) is largely unknown. Further, risk factors of vitamin D deficiency in these patients remain to be elucidated. For this reason, the primary objective of this study was to assess the vitamin D status of patients scheduled to undergo rTJA of the hip, knee and shoulder. The secondary objective was to identify potential risk factors for hypovitaminosis D in these patients. Serum vitamin D [25(OH)D] levels of 249 patients who were scheduled for rTJA were assessed over a period of twelve months at a high-volume TJA centre. Collectively, 23% of patients reported a routine intake of vitamin D supplements (58/249). Notably, 81% of patients (155/191) who did not report a routine vitamin D intake presented with insufficient vitamin D levels (below 30 ng/mL), while only 19% of patients (36/191) had sufficient vitamin D levels. Of those who reported a routine vitamin D intake, 75% (43/58) had sufficient vitamin D levels, while 25% (15/58) showed insufficient vitamin D status. Patients who did not routinely take any vitamin D supplements had significantly lower vitamin D levels compared to patients who reported regular vitamin D intake (19.91 ng/mL vs. 40.66 ng/mL). Further, BMI and nicotine abuse were identified as potential risk factors for hypovitaminosis D in patients without vitamin D supplementation. Moreover, the season of spring seems to be a risk factor in patients with vitamin D supplementation, while age itself did not appear to be a significant risk factor for low vitamin D levels. In conclusion, we found an alarmingly high rate of vitamin D deficiency in patients scheduled to undergo rTJA. Notably, reported routine vitamin D supplementation showed significantly increased serum vitamin D levels compared to patients with no reported supplementation. Due to the high prevalence of vitamin D deficiency, we believe that vitamin D status should routinely be assessed in patients who are scheduled to undergo rTJA.

Objective: The direct anterior approach (DAA) is a recognized technique for total hip arthroplasty (THA) that spares soft tissue. Functional and clinical outcomes following THA via the DAA in patients with complex acetabular deformities, specifically coxa profunda (CP) and protrusio acetabuli (PA), have yet to be determined. Methods : A retrospective analysis was conducted on 188 primary THA cases, including 100 CP hips and 88 PA hips, performed via the DAA. Functional and clinical outcomes were evaluated by means of the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Harris Hip Score (HHS) preoperatively and at a mean follow-up of 46 ± 14 months. Furthermore, potential complications were assessed. Results : From the preoperative to the latest postoperative visit, a significant improvement in the WOMAC total score was observed (CP: -34.89 ± 20.66; PA: -40.38 ± 21.11). The length of stay (LOS) was the only parameter predictive of the postoperative WOMAC total score, with each day of LOS increasing the postoperative WOMAC by a mean of 1.77 points ( p < 0.01). The HHS improved by 38.37 ± 14.23 (PA-group) and 32.79 ± 14.89 points (CP-group). No significant difference in the patient-reported outcome measures (PROMs) between the CP- and PA-group was found. The survival rate for any revision was 97.70% (PA-group) and 92.80% (CP-group). Conclusion : The results of this study indicate that the minimally invasive DAA was not predictive of the functional and clinical outcome following DAA-THA in patients with CP and PA. Improvements in the mean WOMAC and HHS scores were above or within the reported MCID. Additionally, revision rates were well below those reported in the literature for short and intermediate follow-up periods.

Background: Rapidly destructive osteoarthritis (RDO) of the hip joint is characterised by the rapid destruction of the femoral head with or without acetabular involvement. There has been increasing interest in this disease over the past years; however, the entity is still poorly understood, and its pathophysiology remains unknown. Yet, there is ample evidence today that increased bone metabolism might play a role in the onset and progression of the disease. Vitamin D is of utmost importance to maintain a balanced bone metabolism. However, whether vitamin D deficiency is involved in disease development remains to be elucidated. Further, the vitamin D status of patients with RDO has not yet been analysed. For this reason, the objective of this study was to assess the vitamin D status of patients with RDO. Moreover, the aim was to clarify whether there is a difference in the vitamin D status of patients with RDO compared with patients with primary osteoarthritis (OA)., Methods: In this single-centre analysis, the 25(OH)D, PTH, and calcium levels of 29 patients who presented with RDO between 2020 and 2022 were assessed., Results: Altogether, 97% of patients (28/29) were vitamin D deficient, a further 3% (1/29) were vitamin D insufficient, and not a single patient presented with a sufficient vitamin D status. Notably, the vitamin D levels of RDO patients (mean = 11.04 ng/mL) were significantly lower than the vitamin D levels of patients with OA (mean = 22.16 ng/mL, p = 0.001)., Conclusion: In conclusion, we found a widespread and high rate of vitamin D deficiency in patients with RDO. Hence, we believe that 25(OH)D status should routinely be analysed in these patients.

Objective: Direct anterior approach total hip replacement (DAA-THR) is gaining increased interest due to its tissue-sparing nature and rapid recovery. Obesity has been shown to be a significant parameter influencing cup positioning in DAA-THR. It was the intention of this retrospective study to examine how obesity would influence the restoration of native hip biomechanical parameters during DAA-THR., Materials and Methods: A total of 74 patients from a high-volume university orthopedic center after unilateral DAA-THA were included. Patients were retrospectively allocated to a study group (BMI > 30 kg/m 2 ) and a control group (BMI < 30 kg/m 2 ). Furthermore, propensity-score matching for baseline parameters was performed, leaving 30 patients in each group. Biomechanical parameters of the hip (i.e., femoral offset (FO), abductor lever arm (ABL), acetabular offset (AO), center of rotation (COR), stem alignment (SA), body weight lever arm (BWL), cup inclination (CI), and leg length discrepancy (LLD) were evaluated on standardized plain radiographs, and parameters were compared to the native contralateral hip., Results: Mean BMI in the study group was 35.07 ± 5.13 kg/m 2 and 25.43 ± 2.64 kg/m 2 in the control group. There was a significant decrease of the ABL only in the study cohort ( p = 0.01). CI and SA did not differ between both cohorts. FO was slightly increased compared to the native hip in both groups. There was a marginally higher but non-significant proportion of improper FO restoration in the study group (19 vs. 16 patients, p = 0.60)., Conclusions: Obesity, as quantified by BMI, only has a limited impact on the adequate reconstruction of native biomechanical parameters of the hip during DAA-THR. ABL was the only parameter to be significantly decreased in the overweight patients after DAA-THR. Therefore, special care should be taken on proper acetabular reaming and consequent seating of the cup in the obese patient to avoid excessive lateral positioning.

Introduction: The direct anterior approach (DAA) represents a well-recognized soft tissue sparing technique for primary total hip arthroplasty (THA). The feasibility and suitability of the DAA in cases of complex acetabular deformities, namely coxa profunda (CP) and protrusio acetabuli (PA), remain to be determined., Methods: A total of 188 cases of CP (100 cases) and PA (88 cases) hips undergoing primary THA via the DAA were retrospectively analyzed. Surgical and radiographic parameters were evaluated and potential complications were assessed. Finally, successful implantation was defined if surgical and radiographic parameters were well within established values of non-complex primary THA., Results: In 159 hips, the medial border of the acetabular component was transferred laterally to the ilioischial line, corresponding to a fully treated acetabular protrusion. In 23 (12.23%) cases, mild, and in 5 (2.66%) cases, moderate residual acetabular protrusion remained after THA. Postoperatively, 11.40% (PA group) and 9.00% (CP group) had a leg length discrepancy (LLD) greater than 10 mm. The mean operative time was significantly less than 60 min. A linear relationship between the BMI and operative time was observed, with an additional 0.9 min of operative time per BMI unit. Overall, complications were rare and did not differ between the two groups., Conclusion: The results of this study suggest that the DAA is a suitable approach for primary THA in patients with coxa profunda and acetabular protrusion if performed by experienced surgeons familiar with the DAA. Obese patients with acetabular protrusion may pose a significant limitation to the DAA and caution should be advised in cases of obesity.

Purpose: The Area Measurement And Depth Underlying Structures (AMADEUS) classification system has been proposed as a valuable tool for magnetic resonance (MR)-based grading of preoperatively encountered chondral defects of the knee joint. However, the potential relationship of this novel score with clinical data was yet to determine. It was the primary intention of this study to assess the correlative relationship of the AMADEUS with patient reported outcome scores in patients undergoing medial open-wedge high tibial valgus osteotomy (HTO). Furthermore, the arthroscopic ICRS (International Cartilage Repair Society) grade evaluation was tested for correlation with the AMADEUS classification system., Methods: This retrospective, monocentric study found a total of 70 individuals that were indicated for HTO due to degenerative chondral defects of the medial compartment between 2008 and 2019. A preoperative MR image as well as a pre-osteotomy diagnostic arthroscopy for ICRS grade evaluation was mandatory for all patients. The Knee Osteoarthritis Outcome Score (KOOS) including its five subscale scores (KOOS-ADL, KOOS-QOL, KOOS-Sports, KOOS-Pain, KOOS-Symptoms) was obtained preoperatively and at a mean follow-up of 41.2 ± 26.3 months. Preoperative chondral defects were evaluated using the AMADEUS classification system and the final AMADEUS scores were correlated with the pre- and postoperative KOOS subscale sores. Furthermore, arthroscopic ICRS defect severity was correlated with the AMADEUS classification system., Results: There was a statistically significant correlation between the AMADEUS BME (bone marrow edema) subscore and the KOOS Symptoms subscore at the preoperative visit (r = 0.25, p = 0.04). No statistically significant monotonic association between the AMADEUS total score and the AMADEUS grade with pre- and postoperative KOOS subscale scores were found. Intraoperatively obtained ICRS grade did reveal a moderate correlative relation with the AMADEUS total score and the AMADEUS grade (r = 0.28, p = 0.02)., Conclusions: The novel AMADEUS classification system largely lacks correlative capacity with patient reported outcome measures in patients undergoing HTO. The MR tomographic appearance of bone marrow edema is the only parameter predictive of the clinical outcome at the preoperative visit., (© 2023. The Author(s).)

Active vitamin D (1,25(OH)2D3) is known to exert direct anti-cancer actions on various malignant tissues through binding to the vitamin D receptor (VDR). These effects have been demonstrated in breast, prostate, renal and thyroid cancers, which all have a high propensity to metastasise to bone. In addition, there is evidence that vitamin D catabolism via 24-hydroxylase (CYP24A1) is altered in tumour cells, thus, reducing local active vitamin D levels in cancer cells. The aim of this study was to assess VDR and CYP24A1 expression in various types of bone metastases by using immunohistochemistry. Overall, a high total VDR protein expression was detected in 59% of cases (39/66). There was a non-significant trend of high-grade tumours towards the low nuclear VDR expression ( p = 0.07). Notably, patients with further distant metastases had a reduced nuclear VDR expression ( p = 0.03). Furthermore, a high CYP24A1 expression was detected in 59% (39/66) of bone metastases. There was a significant positive correlation between nuclear VDR and CYP24A1 expression ( p = 0.001). Collectively, the VDR and CYP24A1 were widely expressed in a multitude of bone metastases, pointing to a potential role of vitamin D signalling in cancer progression. This is of high clinical relevance, as vitamin D deficiency is frequent in patients with bone metastases.

Purpose: The AMADEUS (Area Measurement And DEpth and Underlying Structures) scoring and grading system has been proposed for the MRI based evaluation of untreated focal chondral defects around the knee. The clinical practicability, its correlation with arthroscopically assessed grading systems (ICRS - International Cartilage Repair Society) and thereby its clinical value in terms of decision making and guiding prognosis was yet to determine., Methods: From 2008 to 2019 a total of 89 individuals were indicated for high tibial valgus osteotomy (HTO) due to tibial varus deformity and concomitant chondral defects of the medial compartment of the knee. All patients received a preoperative MRI (1.5 Tesla or 3.0 Tesla) and pre-osteotomy diagnostic arthroscopy. Chondral defects of the medial compartment were scored and graded with the MRI based AMADEUS by three independent raters and compared to arthroscopic defect grading by the ICRS system. Interrater and intrarater reliability as well as correlation analysis with the ICRS classification system were assessed., Results: Intraclass correlation coefficients for the various subscores of the AMADEUS showed an overall good to excellent interrater agreement (min: 0.26, max: 0.80). Intrarater agreement turned out to be substantially inferior (min: 0.08, max: 0.53). Spearman correlation revealed an overall moderate correlative association of the AMADEUS subscores with the ICRS classification system, apart from the defect area subscore. Sensitivity of the AMADEUS to accurately identify defect severity according to the ICRS was 0.7 (0.69 for 3.0 Tesla MRI, 0.67 for 1.5 Tesla MRI). The mean AMADEUS grade was 2.60 ± 0.81 and the mean ICRS score 2.90 ± 0.63., Conclusions: Overall, the AMADEUS with all its subscores shows moderate correlation with the arthroscopic chondral grading system according to ICRS. This suggests that chondral defect grading by means of the MRI based AMADEUS is well capable of influencing and guiding treatment decisions. Interrater reliability shows overall good agreement., (© 2022. The Author(s).)

Purpose: Despite much improved preoperative planning techniques accurate intraoperative assessment of the high tibial valgus osteotomy (HTO) remains challenging and often results in coronal over- and under-corrections as well as unintended changes of the posterior tibial slope. Noyes et al. reported a novel method for accurate intraoperative coronal and sagittal alignment correction based on a three-dimensional mathematical model. This is the first study examining preliminary data via the proposed Noyes approach for accurate intraoperative coronal and sagittal alignment correction during HTO., Methods: From 2016 to 2020 a total of 24 patients (27 knees) underwent HTO applying the proposed Noyes method (Noyes-Group). Radiographic data was analyzed retrospectively and matched to patients that underwent HTO using the conventional method, i.e., gradual medial opening using a bone spreader under fluoroscopic control (Conventional-Group). All operative procedures were performed by an experienced surgeon at a single orthopaedic university center., Results: From the preoperative to the postoperative visit no statistically significant changes of the posterior tibial slope were noted in the Noyes-Group compared to a significant increase in the Conventional-Group (p = 0.01). Regarding the axial alignment no significant differences between both groups were observed pre- and postoperatively. The number of over- and under-corrections did not differ significantly between both groups. Linear regression analysis showed a significant correlation of the postoperative medial proximal tibial angle (MPTA) with the position of the weightbearing line on the tibial plateau., Conclusion: The 3-triangle method by Noyes seems to be a promising approach for preservation of the posterior tibial slope during HTO., (© 2022. The Author(s).)

Vitamin D is considered to play an important role in musculoskeletal health. It's classical function is the regulation of calcium and phosphate homeostasis, thus ensuring a balanced bone metabolism that is characterised by an equal amount of bone resorption and bone formation. In the past decades, a plethora of pre-clinical and clinical studies reporting on potential health-beneficial properties of vitamin D have emerged. Moreover, there is an abundance of reports highlighting vitamin D deficiency and insufficiency in patients with almost innumerable diseases. Further, it is estimated that more than one billion people globally are affected by insufficient vitamin D levels. As such, research on vitamin D has been particularly popular over the past years. In orthopaedics and traumatology, most studies describe favourable effects of vitamin D in general. However, the relative importance of vitamin D is oftentimes debated. In this narrative review of the literature, we consider first, the properties of vitamin D and how vitamin D, vitamin D deficiency and the vitamin D receptor (VDR) impact on musculoskeletal health. Secondly, we provide an overview of studies reporting the prevalence of vitamin D deficiency in traumatology and diverse orthopaedic diseases including bone oncology. Lastly, we emphasise recent findings and touch on future perspectives in vitamin D research., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/atm-21-779). The authors have no conflicts of interest to declare., (2021 Annals of Translational Medicine. All rights reserved.)

Background: Aiming at an early identification of patients with an unsatisfactory outcome after hip arthroplasty we investigated the pre-, intra- and early postoperative predictability., Methods: Using logistic regression models at nine different time points we calculated the area under the curve of the receiver operating characteristic (ROC-AUC) to compare the predictability of an unsatisfactory outcome., Results: The predictability of unsatisfactory outcomes increased significantly from a ROC-AUC (95% CI) of 0.73 (0.62-0.84) in the preoperative setting to 0.85 (0.77-0.94) on day 2 after surgery., Conclusion: Most of the patients with unsatisfactory outcomes can be identified during the first days after surgery., (© 2021 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

The topical application of tranexamic acid (TXA) helps to prevent post-operative blood loss in total joint replacements. Despite these findings, the effects on articular and periarticular tissues remain unclear. Therefore, this in vitro study examined the effects of varying exposure times and concentrations of TXA on proliferation rates, gene expression and differentiation capacity of chondrocytes and human mesenchymal stromal cells (hMSCs), which underwent osteogenic differentiation. Chondrocytes and hMSCs were isolated and multiplied in monolayer cell cultures. Osteogenic differentiation of hMSCs was induced for 21 days using a differentiation medium containing specific growth factors. Cell proliferation was analyzed using ATP assays. Effects of TXA on cell morphology were examined via light microscopy and histological staining, while expression levels of tissue-specific genes were measured using semiquantitative RT-PCR. After treatment with 50 mg/mL of TXA, a decrease in cell proliferation rates was observed. Furthermore, treatment with concentrations of 20 mg/mL of TXA for at least 48 h led to a visible detachment of chondrocytes. TXA treatment with 50 mg/mL for at least 24 h led to a decrease in the expression of specific marker genes in chondrocytes and osteogenically differentiated hMSCs. No significant effects were observed for concentrations beyond 20 mg/mL of TXA combined with exposure times of less than 24 h. This might therefore represent a safe limit for topical application in vivo. Further research regarding in vivo conditions and effects on hMSC functionality are necessary to fully determine the effects of TXA on articular and periarticular tissues.

Background: For improved outcomes in total knee arthroplasty (TKA) correct implant fitting and positioning are crucial. In order to facilitate a best possible implant fitting and positioning patient-specific systems have been developed. However, whether or not these systems allow for better implant fitting and positioning has yet to be elucidated. For this reason, the aim was to analyse the novel patient-specific cruciate retaining knee replacement system iTotal™ CR G2 that utilizes custom-made implants and instruments for its ability to facilitate accurate implant fitting and positioning including correction of the hip-knee-ankle angle (HKA)., Methods: We assessed radiographic results of 106 patients who were treated with the second generation of a patient-specific cruciate retaining knee arthroplasty using iTotal™ CR G2 (ConforMIS Inc.) for tricompartmental knee osteoarthritis (OA) using custom-made implants and instruments. The implant fit and positioning as well as the correction of the mechanical axis (hip-knee-ankle angle, HKA) and restoration of the joint line were determined using pre- and postoperative radiographic analyses., Results: On average, HKA was corrected from 174.4° ± 4.6° preoperatively to 178.8° ± 2.2° postoperatively and the coronal femoro-tibial angle was adjusted on average 4.4°. The measured preoperative tibial slope was 5.3° ± 2.2° (mean +/- SD) and the average postoperative tibial slope was 4.7° ± 1.1° on lateral views. The joint line was well preserved with an average modified Insall-Salvati index of 1.66 ± 0.16 pre- and 1.67 ± 0.16 postoperatively. The overall accuracy of fit of implant components was decent with a measured medial overhang of more than 1 mm (1.33 mm ± 0.32 mm) in 4 cases only. Further, a lateral overhang of more than 1 mm (1.8 mm ± 0.63) (measured in the anterior-posterior radiographs) was observed in 11 cases, with none of the 106 patients showing femoral notching., Conclusion: The patient-specific iTotal™ CR G2 total knee replacement system facilitated a proper fitting and positioning of the implant components. Moreover, a good restoration of the leg axis towards neutral alignment was achieved as planned. Nonetheless, further clinical follow-up studies are necessary to validate our findings and to determine the long-term impact of using this patient- specific system.

Vitamin D deficiency is a global health concern that is estimated to afflict over one billion people globally. The major role of vitamin D is that of a regulator of calcium and phosphate metabolism, thus, being essential for proper bone mineralisation. Concomitantly, vitamin D is known to exert numerous extra-skeletal actions. For example, it has become evident that vitamin D has direct anti-proliferative, pro-differentiation and pro-apoptotic actions on cancer cells. Hence, vitamin D deficiency has been associated with increased cancer risk and worse prognosis in several malignancies. We have recently demonstrated that vitamin D deficiency promotes secondary cancer growth in bone. These findings were partly attributable to an increase in bone remodelling but also through direct effects of vitamin D on cancer cells. To date, very little is known about vitamin D status of patients with bone tumours in general. Thus, the objective of this study was to assess vitamin D status of patients with diverse bone tumours. Moreover, the aim was to elucidate whether or not there is an association between pre-diagnostic vitamin D status and tumour malignancy in patients with bone tumours. In a multi-center analysis, 25(OH)D, PTH and calcium levels of 225 patients that presented with various bone tumours between 2017 and 2018 were assessed. Collectively, 76% of all patients had insufficient vitamin D levels with a total mean 25(OH)D level of 21.43 ng/ml (53.58 nmol/L). In particular, 52% (117/225) of patients were identified as vitamin D deficient and further 24% of patients (55/225) were vitamin D insufficient. Notably, patients diagnosed with malignant bone tumours had significantly lower 25(OH)D levels than patients diagnosed with benign bone tumours [19.3 vs. 22.75 ng/ml (48.25 vs. 56.86 nmol/L); p = 0.04). In conclusion, we found a widespread and distressing rate of vitamin D deficiency and insufficiency in patients with bone tumours. However, especially for patients with bone tumours sufficient vitamin D levels seem to be of great importance. Thus, we believe that 25(OH)D status should routinely be monitored in these patients. Collectively, there should be an increased awareness for physicians to assess and if necessary correct vitamin D status of patients with bone tumours in general or of those at great risk of developing bone tumours., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 The Authors.)

Despite increasing numbers of primary hip arthroplasties performed through the direct anterior approach (DAA), there is a lack of literature on DAA revision arthroplasty. The present study was performed in order to evaluate outcomes and revision rates after revision through the DAA using an asymmetric acetabular component with optional intra- and extramedullary fixation. In a retrospective cohort study, we analyzed prospectively collected data of 57 patients (61 hips, 43 female, 18 male) who underwent aseptic acetabular component revision through the DAA with the abovementioned implant system between January 2015 and December 2017. The mean follow-up was 40 months (12-56). Survival rates were estimated using the Kaplan-Meier method. All complications were documented and functional outcomes were assessed pre- and postoperatively. Kaplan-Meier analysis revealed an estimated five-year implant survival of 97% (confidence interval CI 87-99%). The estimated five-year survival with revision for any cause was 93% (CI 83-98%). The overall revision rate was 6.6% (n = 4). Two patients had to undergo revision due to periprosthetic infection (3.3%). In one patient, the acetabular component was revised due to aseptic loosening four months postoperatively. Another patient suffered from postoperative iliopsoas impingement and was treated successfully by arthroscopic iliopsoas tenotomy. Two (3.3%) of the revised hips dislocated postoperatively. The mean Harris Hip Score improved from 35 (2-66) preoperatively to 86 (38-100) postoperatively ( p < 0.001). The hip joint's anatomical center of rotation was restored at a high degree of accuracy. Our findings demonstrate that acetabular revision arthroplasty through the DAA using an asymmetric acetabular component with optional intra- and extramedullary fixation is safe and practicable, resulting in good radiographic and clinical midterm results.

Background: While multiple in vitro studies examined mesenchymal stromal cells (MSCs) derived from bone marrow or hyaline cartilage, there is little to no data about the presence of MSCs in the joint capsule or the ligamentum capitis femoris (LCF) of the hip joint. Therefore, this in vitro study examined the presence and differentiation potential of MSCs isolated from the bone marrow, arthritic hyaline cartilage, the LCF and full-thickness samples of the anterior joint capsule of the hip joint., Methods: MSCs were isolated and multiplied in adherent monolayer cell cultures. Osteogenesis and adipogenesis were induced in monolayer cell cultures for 21 days using a differentiation medium containing specific growth factors, while chondrogenesis in the presence of TGF-ß1 was performed using pellet-culture for 27 days. Control cultures were maintained for comparison over the same duration of time. The differentiation process was analyzed using histological and immunohistochemical stainings as well as semiquantitative RT-PCR for measuring the mean expression levels of tissue-specific genes., Results: This in vitro research showed that the isolated cells from all four donor tissues grew plastic-adherent and showed similar adipogenic and osteogenic differentiation capacity as proven by the histological detection of lipid droplets or deposits of extracellular calcium and collagen type I. After 27 days of chondrogenesis proteoglycans accumulated in the differentiated MSC-pellets from all donor tissues. Immunohistochemical staining revealed vast amounts of collagen type II in all differentiated MSC-pellets, except for those from the LCF. Interestingly, all differentiated MSCs still showed a clear increase in mean expression of adipogenic, osteogenic and chondrogenic marker genes. In addition, the examination of an exemplary selected donor sample revealed that cells from all four donor tissues were clearly positive for the surface markers CD44, CD73, CD90 and CD105 by flow cytometric analysis., Conclusions: This study proved the presence of MSC-like cells in all four examined donor tissues of the hip joint. No significant differences were observed during osteogenic or adipogenic differentiation depending on the source of MSCs used. Further research is necessary to fully determine the tripotent differentiation potential of cells isolated from the LCF and capsule tissue of the hip joint.

Expression of the vitamin D receptor (VDR) is thought to be associated with neoplastic progression. However, the role of the VDR in breast cancer metastasis to bone and the molecular mechanisms underlying this process are unknown. Employing a rodent model (female Balb/c nu/nu mice) of systemic metastasis, we here demonstrate that knockdown of the VDR strongly increases the metastatic potential of MDA-MB-231 human breast cancer cells to bone, resulting in significantly greater skeletal tumor burden. Ablation of VDR expression promotes cancer cell mobility (migration) and invasiveness, thereby facilitating skeletal colonization. Mechanistically, these changes in tumor cell behavior are attributable to shifts in the expression of proteins involved in cell adhesion, proliferation, and cytoskeletal organization, patterns characteristic for epithelial-to-mesenchymal cell transition (EMT). In keeping with these experimental findings, analyses of human breast cancer specimens corroborated the association between VDR expression, EMT-typical changes in protein expression patterns, and clinical prognosis. Loss of the VDR in human breast cancer cells marks a critical point in oncogenesis by inducing EMT, promoting the dissemination of cancer cells, and facilitating the formation of tumor colonies in bone. © 2019 American Society for Bone and Mineral Research., (© 2019 American Society for Bone and Mineral Research.)

Vitamin D co-regulates cell proliferation, differentiation and apoptosis in numerous tissues, including cancers. The known anti-proliferative and pro-apoptotic actions of the active metabolite of vitamin D, 1,25-dihydroxy-vitamin D [1,25(OH) 2 D] are mediated through binding to the vitamin D receptor (VDR). Here, we report on the unexpected finding that stable knockdown of VDR expression in the human breast and prostate cancer cell lines, MDA-MB-231 and PC3, strongly induces cell apoptosis and inhibits cell proliferation in vitro. Implantation of these VDR knockdown cells into the mammary fat pad (MDA-MB-231), subcutaneously (PC3) or intra-tibially (both cell lines) in immune-incompetent nude mice resulted in reduced tumor growth associated with increased apoptosis and reduced cell proliferation compared with controls. These growth-retarding effects of VDR knockdown occur in the presence and absence of vitamin D and are independent of whether cells were grown in bone or soft tissues. Transcriptome analysis of VDR knockdown and non-target control cell lines demonstrated that loss of the VDR was associated with significant attenuation in the Wnt/β-catenin signaling pathway. In particular, cytoplasmic and nuclear β-catenin protein levels were reduced with a corresponding downregulation of downstream genes such as Axin2, Cyclin D1, interleukin-6 (IL-6), and IL-8. Stabilization of β-catenin using the GSK-3β inhibitor BIO partly reversed the growth-retarding effects of VDR knockdown. Our results indicate that the unliganded VDR possesses hitherto unknown functions to promote breast and prostate cancer growth, which appear to be operational not only within but also outside the bone environment. These novel functions contrast with the known anti-proliferative nuclear actions of the liganded VDR and may represent targets for new diagnostic and therapeutic approaches in breast and prostate cancer., Competing Interests: The authors declare no conflict of interest.

Background: The purpose of this observational study was to evaluate serum levels of 25-OH-D in patients scheduled to undergo elective hip or knee arthroplasty. We hypothesised that 25-OH-D level is an independent risk factor for length of stay in orthopaedic patients after elective hip or knee arthoplasty., Materials and Methods: 25-OH-D levels were measured in 1083 patients admitted to an orthopaedic surgery department to undergo elective hip or knee arthroplasty. Comparisons were performed using Chi square or Student's t test, followed by univariate and multiple linear regression analysis examining the correlation between the length of stay in the orthopaedic department and 25-OH-D level while adjusting for possible confounders., Results: Overall, 86 % of patients had insufficient serum levels of 25-OH-D, and over 60 % were vitamin D deficient. The mean length of stay was 13.2 ± 8.3 days. In patients with hypovitaminosis D, the length of stay was significantly longer compared to patients with normal serum 25-OH-D levels (15.6 ± 7.2 compared to 11.3 ± 7.9 days, P = 0.014). In univariate analyses, serum 25-OH-D level was inversely related to the length of stay in our orthopaedic department compared to patients with normal vitamin D levels (r = -0.16; P = 0.008). In multivariate analyses, the length of stay remained significantly associated with low 25-OH-D levels (P = 0.002), indicating that low vitamin D levels increase the length of stay., Conclusions: We found a high frequency of hypovitaminosis D among orthopaedic patients scheduled to undergo elective arthroplastic surgery. Low vitamin D levels showed a significant inverse association to the length of stay in our orthopaedic department. Patients with vitamin D levels in the target range were hospitalised 4.3 days less than patients with hypovitaminosis D. Level 3 of evidence according to "The Oxford 2011 levels of evidence"., Competing Interests: Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. Ethical standards All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee, and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent Informed consent was obtained from all individual participants included in the study.

An intramedullary device has some advantages over external fixation in callus distraction for bone defect reconstruction. There are difficulties controlling motorized intramedullary devices and monitoring the distraction rate which may lead to poor results. The aim of this study was to design a fully implantable and non-motorized simple distraction nail for the treatment of bone defects. The fully implantable device comprises a tube-in-tube system and a wire pulling mechanism for callus distraction. For the treatment of femoral bone defects, a traction wire, attached to the device at one end, is fixed to the tibial tubercle at its other end. Flexion of the knee joint over a predetermined angle generates a traction force on the wire triggering bone segment transport. This callus distraction system was implanted into the femur of four human cadavers (total 8 femora), and bone segment transport was conducted over 60-mm defects with radiographic monitoring. All bone segments were transported reliably to the docking site. From these preliminary results, we conclude that this callus distraction system offers an alternative to the current intramedullary systems for the treatment of bone defects.

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.

Background/aim: Breast and prostate cancer are amongst the most prevalent malignancies globally and up to 40% of patients will develop metastatic disease, particularly to the skeleton. Multiple myeloma is the most common cancer to affect bone with up to 90% of patients developing bone lesions. Although several studies demonstrated that endocrine changes such as vitamin D deficiency promote secondary cancer growth in bone, relatively few have reported its prevalence. For this reason, the purpose of the present study was to evaluate the prevalence of hypovitaminosis D in patients with bone metastases and multiple myeloma., Patients and Methods: Serum 25-OH-D levels of patients with metastatic bone disease were measured on admission. Statistical analyses was performed to evaluate for possible confounders of hypo-vitaminosis D., Results: We found a widespread and alarming rate of vitamin D deficiency in patients with metastatic bone disease and multiple myeloma. Of note, patients with bone metastases due to breast cancer, prostate cancer and multiple myeloma rarely reached sufficient serum 25-OH-D levels., Conclusion: It is of utmost clinical importance to assess vitamin D levels in cancer patients, especially in those with, or at high risk of developing metastatic bone disease., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Callus distraction using bone segment transport systems is an applied process in the treatment of bone defects. However, complications such as muscle contractures, axial deviation and pin track infections occur in the treatment process using the currently available devices. Since successful treatment is influenced by the applied distraction force, knowledge of the biomechanical properties of the involved soft tissues is essential to improve clinical outcome and treatment strategies. To date, little data on distraction forces and the role of soft-tissue traction forces are available. The aim of this study was to assess traction forces generated by soft tissues during bone segment transport using a novel intramedullary callus distraction system on eight human femora. For traction force measurements, bone segment transport over 60-mm femoral defects was conducted under constant load measurement using 40- and 60-mm bone segments. The required traction forces for 60-mm bone segments were higher than forces for 40-mm bone segments. This study demonstrates that soft tissues are of relevance biomechanically in bone segment transport. The size of the bone segment and the selection of the region for osteotomy are of utmost importance in defining the treatment procedure.

Purpose: Vitamin D is increasingly being recognized as an important mediator of immune function and may have a preventive role in the pathogenesis of periprosthetic joint infection. To the best of our knowledge, no other study has examined possible associations between periprosthetic joint infection and vitamin D deficiency. We investigated the rate of vitamin D deficiency in patients treated for periprosthetic joint infection and whether vitamin D deficiency is independent of other risk factors for vitamin D deficiency in patients with periprosthetic joint infection., Methods: Serum 25-hydroxyvitamin D (25OHD) levels of every patient scheduled to receive a total prosthesis either of the hip, knee, or shoulder in the orthopaedic department of the Johannes-Guttenberg-University Hospital in Mainz, Germany (109 patients), were measured after admission. Furthermore, serum 25OHD levels were measured for every patient presenting with periprosthetic joint infection (n = 50) or aseptic loosening of the prosthesis (n = 31) scheduled to undergo revision surgery. The prevalence of normal (> 30 ng/ml), insufficient (20-30 ng/ml), and deficient (<20 ng/ml) 25OHD levels was determined., Results: All tested patient subgroups showed low vitamin D levels. Statistical analysis found no significant difference in vitamin D levels comparing patients with prosthesis and patients with aseptic prosthesis loosening (p = 0.58). Significant differences in 25OHD levels were found comparing patients with periprosthetic joint infection and patients scheduled for primary arthroplasty (p < 0.001). In addition, we found a significant difference (p < 0,001) in 25OHD levels of patients with periprosthetic joint infection compared with patients with aseptic prosthesis loosening., Conclusion: We found a high frequency of vitamin D deficiency in patients being treated by primary arthroplasty and those with aseptic joint prosthetic loosening and periprosthetic joint infection. Vitamin D deficiency was severe in patients with periprosthetic joint infection.