Norbert Harrasser

Background: Electromagnetic field therapy is gaining attention for its potential in treating bone disorders, with Extracorporeal Magnetotransduction Therapy (EMTT) emerging as an innovative approach. EMTT offers a higher oscillation frequency and magnetic field strength compared to traditional Pulsed Electromagnetic Field (PEMF) therapy, showing promise in enhancing fracture healing and non-union recovery. However, the mechanisms underlying these effects remain unclear. Results: This study demonstrates that EMTT significantly enhances osteoblast bone formation at multiple levels, from gene expression to extracellular matrix mineralization. Key osteoblastogenesis regulators, including SP7 and RUNX2, and bone-related genes such as COL1A1, ALPL, and BGLAP, were upregulated, with expression levels surpassing those of the control group by over sevenfold (p < 0.001). Enhanced collagen synthesis and mineralization were confirmed by von Kossa and Alizarin Red staining, indicating increased calcium and phosphate deposition. Additionally, calcium imaging revealed heightened calcium influx, suggesting a cellular mechanism for EMTT’s osteogenic effects. Importantly, EMTT did not compromise cell viability, as confirmed by live/dead staining and WST-1 assays. Conclusion: This study is the first to show that EMTT can enhance all phases of osteoblastogenesis and improve the production of critical mineralization components, offering potential clinical applications in accelerating fracture healing, treating osteonecrosis, and enhancing implant osseointegration.

The rarity of foot and ankle tumours, together with the numerous histological entities, presents a challenge in accumulating sufficient patients to draw reliable conclusions. Therefore, we decided to present an update of a retrospective analysis of their distribution patterns, comprising 536 cases of foot and ankle tumours presented to our tumour board between June 1997 and June 2023. Our aim was to provide a comprehensive overview of the prevalence and distribution patterns of benign and malignant bone and soft tissue tumours of the foot and ankle. A total of 277 tumours involved bone (51.7%). Of these, 242 (87.4%) were benign and 35 (12.6%) were malignant. In addition, 259 soft tissue tumours (48.3%) were found, of which 191 (73.7%) were benign and 68 (26.3%) were malignant. The most common benign bone tumours were simple bone cysts, enchondromas, osteochondromas, aneurysmal bone cysts, and lipomas of bone. Common benign soft tissue tumours included a tenosynovial giant cell tumour, haemangioma, plantar fibromatosis, schwannoma, and lipoma. The most common malignant soft tissue tumours were synovial sarcoma, malignant melanoma, and myxofibrosarcoma. In terms of anatomical location, the hindfoot was the most common site (28.7%), followed by the midfoot (25.9%), ankle (25.4%), and forefoot (20.0%). The distribution of benign entities often follows typical patterns, which may facilitate an early diagnosis even without biopsy (e.g., simple bone cyst, plantar fibromatosis). On the other hand, the distribution patterns of many rare or malignant entities are inconsistent. Individual soft tissue malignancies occur very sporadically, even over long periods of time and in specialized tumour centres. It is therefore important to recognise that any suspicious mass in the foot and ankle must be considered a possible malignancy until proven otherwise.

Introduction: Minimally invasive calcaneal osteotomy (MICO) is already an established surgical procedure for correcting hindfoot deformities using a lateral approach. So far, no description of a medial approach for MICO has been published. Material and methods: Between August 2022 and March 2023, 32 consecutive patients (MICO with medial approach, MMICO: n = 15; MICO with lateral approach, LMICO: n = 17) underwent MICO as part of complex reconstructive surgery of the foot and ankle with concomitant procedures. The amount of correction in the axial view of the calcaneus and consolidation rates were evaluated radiographically. Subjective satisfaction, stiffness of the subtalar joint, and pain level (numeric rating scale, NRS) at the level of the heel were assessed clinically. The last follow-up was at 6 months. Results: All osteotomies consolidated within 6 months after surgery. Displacement of the tuber was 9 mm on average in either group. Relevant subtalar joint stiffness was detected in 5 MMICO and 6 LMICO patients. No relevant differences between the groups were detected for wound healing problems, nerve damage, heel pain or patient satisfaction. Conclusion: In this study lateral and medial approaches for MICO were performed. Similar degrees of correction and low complication rates were found in both groups. The medial approach for MICO is safe and can be beneficial regarding patient positioning and arrangement of the C‑arm. Graphic

Introduction: To evaluate the clinical and radiological results after fixation of the first metatarsal head (MTH) with one or two screws as part of the third-generation minimally invasive Chevron–Akin osteotomy (MICA) for hallux valgus deformities. Materials and methods: Between August 2020 and November 2021, 55 MICA procedures (50 patients, male:female = 7:43), 22 with two (MICA2), 33 with one screw (MICA1) were performed for mild to severe hallux valgus deformities. Exclusion criteria were a concomitant pes adductus (Sgarlato angle > 20°) or hindfoot/midfoot deformities requiring treatment. In 27 cases, additional procedures on the forefoot (small toe corrections or metatarsal osteotomies II–V) were necessary. Pre- and post-operatively, hallux valgus angle (HVA) and intermetatarsal I/II angle (IMA) were measured. Clinically, subjective satisfaction, range of motion (ROM) of the first metatarsophalangeal joint (MTPJ), and pain level (NRS score) were evaluated. The minimum follow-up was 12 months. Results: Displacement of MTH was 70–90% on average, all osteotomies showed full consolidation at latest follow-up. In one case of either group, a slight subsidence of MTH was documented. The radiological and clinical parameters showed no differences between the groups. The pain level improved by an average of three points. The mobility of the MTPJ showed a slight reduction in nine cases after three months (4 MICA2, 5 MICA1) which persisted in three cases. Fifty-two of 55 patients (95%) would opt again for the operation. Conclusions: Fixation of the first MTH with a single bicortical screw in MICA with moderate lateralization of MTH shows stable anchoring and good clinical results. The routine use of a second metatarsal screw can be omitted.

Zusammenfassung Die minimal-invasive Chirurgie („minimally-invasive surgery“ [MIS]) stellt mittlerweile ein etabliertes Verfahren in der Korrektur sämtlicher Deformitäten des Vorfußes dar. Am ersten Strahl zeigt die minimal-invasive Chevron-/Akin-Osteotomie (MICA) sehr gute Ergebnisse und bietet im Vergleich zur klassischen Chevron-Osteotomie ein breiteres Indikationsspektrum. Die Therapie des Hallux rigidus scheint minimal-invasiv ebenfalls vergleichbare Ergebnisse zu liefern wie die offenen Techniken, hierbei muss allerdings eine sorgfältige Indikationsstellung erfolgen. Kleinzehendeformitäten sind minimal-invasiv durch Osteotomien und Kapsel‑/Sehnenverlängerungen häufig einfacher zu therapieren als durch aufwendige offene Verfahren und benötigen in der Regel kein Osteosynthesematerial. Distale metatarsale Osteotomien zeigen im Vergleich zur klassischen Weil-Osteotomie eine reduzierte Rate an „Cock-up“-Deformitäten und bedürfen keiner internen Fixierung. In Bezug zu offenen Verfahren sollte das minimal-invasive Vorgehen aufgrund der reduzierten Rate an Wundheilungsstörungen und postoperativen Schmerzen als wertvolle Ergänzung und Alternative zu den klassischen Techniken gesehen werden.

Background: A pathological/inflamed cellular microenvironment state is an additional risk factor for any cancer type. The importance of a chronic inflammation state in most diffuse types of tumour has already been analysed, except for in Ewing’s sarcoma. It is a highly malignant blue round cell tumour, with 90% of cases occurring in patients aged between 5 and 25 years. Worldwide, 2.9 out of 1,000,000 children per year are affected by this malignancy. The aim of this retrospective study was to analyse the role of C-reactive protein (CRP) as a prognostic factor for Ewing’s sarcomas. Methods: This retrospective study at Klinikum rechts der Isar included 82 patients with a confirmed Ewing’s sarcoma diagnosis treated between 2004 and 2019. Preoperative CRP determination was assessed in mg/dL with a normal value established as below 0.5 mg/dL. Disease-free survival time was calculated as the time between the initial diagnosis and an event such as local recurrence or metastasis. Follow-up status was described as death of disease (DOD), no evidence of disease (NED) or alive with disease (AWD). The exclusion criteria of this study included insufficient laboratory values and a lack of information regarding the follow-up status or non-oncological resection. Results: Serum CRP levels were significantly different in patients with a poorer prognosis (DOD) and in patients who presented distant metastasis (p = 0.0016 and p = 0.009, respectively), whereas CRP levels were not significantly different in patients with local recurrence (p = 0.02). The optimal breakpoint that predicted prognosis was 0.5 mg/dL, with a sensitivity of 0.76 and a specificity of 0.74 (AUC 0.81). Univariate CRP analysis level >0.5 mg/dL revealed a hazard ratio of 9.5 (95% CI 3.5–25.5). Conclusions: In Ewing’s sarcoma cases, we consider a CRP pretreatment value >0.5 mg/dL as a sensitive prognostic risk factor indication for distant metastasis and poor prognosis. Further research with more data is required to determine more sensitive cutoff levels.