Markus Weber

Zusammenfassung Auffällige Röntgen- und MRT-Befunde bei älteren Patienten sind häufig und erfordern eine rasche Abklärung, um maligne Erkrankungen von harmlosen Zufallsbefunden zu unterscheiden. Eine sorgfältige Anamnese inklusive Vorerkrankungen und Voraufnahmen ist essenziell. Konventionelle Röntgenaufnahmen liefern unter Anwendung der Lodwick-Klassifikation erste Hinweise zur Dignität der Läsionen. Ergänzt wird die Diagnostik durch eine MRT mit Kontrastmittel sowie ggf. eine zusätzliche CT. Häufigste maligne Knochentumoren im Alter sind Metastasen, gefolgt von Lymphomen, Plasmozytomen und seltener primären Knochentumoren. Das Frakturrisiko lässt sich an den Extremitäten mit dem Mirels-Score und an der Wirbelsäule mit dem SINS-Score (Spinal Instability Neoplastic Score) abschätzen. Bei unklarem Befund ist eine Biopsie zur weiteren Abklärung notwendig. Diese sollte an einem entsprechenden Tumorzentrum durchgeführt werden. Die Therapie richtet sich nach der Tumorentität und Ausbreitung und beinhaltet operative Maßnahmen, Strahlen- und Chemotherapie. Wichtigstes Indiz für das Vorliegen einer pathologischen Fraktur ist das inadäquate Trauma.

Impingement is a significant complication following total hip arthroplasty (THA), resulting in restricted range of motion (ROM). Pelvic tilt (PT) and its variation could alter both post‐THA ROM and impingement types, which remains relatively unexplored in the literature. Therefore, this study aims to investigate the impact of PT changes on post‐THA ROM and impingement types. Subject‐specific ROM was simulated using 3D‐CT and clinical data for 56 THA patients. Subsequently, the effect of no‐PT, standing preoperative (StPT₀) and postoperative PT at 6 (StPT₆) and 12 months (StPT₁₂) on maximum ROM (flexion, extension, abduction, adduction, external rotation (ER) and internal rotation at 90° Flexion (IR@90°Flex)) and impingement types (implant‐to‐implant impingement (ITII), implant‐to‐bone impingement (ITBI), and bone‐to‐bone impingement (BTBI)) were investigated. Stong correlations existed between PT and flexion (R² ≥ 0.686), extension (R² ≥ 0.527), and IR@90°Flex (R² ≥ 0.547). Anterior PT exceeding 8.1° and 11.8° were linked to decreased flexion below 110° and IR@90°Flex below 30°, respectively. Each 10° increase in anterior PT resulted in a 10° reduction in flexion and a 10.7° reduction in IR@90°Flex. Impingement types due to PT remained unchanged for flexion/extension, with increased ITII for abduction (8.9%), adduction (23.2%), and IR@90°Flex (16.1%), and increased BTBI (16.1%) for ER. In total, 12.5% and 19.6% of patients experienced clinically relevant ROM change for flexion and IR@90°Flex, respectively for StPT₀–StPT₆. However, it affected below 5.4% cases when comparing StPT₆ and StPT₁₂. Minor changes in impingement type (< 6% of cases) were observed due to changes in PT before and after THA, as well as temporal changes in PT post‐THA. However, PT had a substantial impact on impingement types when comparing ROM without considering PT to ROM with PT included. Specifically, anterior PT was associated with reduced flexion and IR@90°Flex, indicating a higher risk of impingement. PT changes over time may lead to clinically relevant alterations in ROM but not impingement types.Trial Registration: German Clinical Trials Register; Main ID: DRKS00000739.

Rationale: The infantile fibrosarcoma (IFS) is a non-rhabdomyosarcoma soft tissue sarcoma with locally aggressive properties. State of the art therapy consists of neoadjuvant chemotherapy followed by wide resection according to the criteria of the musculoskeletal tumor society. Diagnoses: An ETV6-NTRK3 positive IFS of the distal tibia in a 21-months old child showed good response to chemotherapy. Interventions: Due to refusal of amputation marginal resection completing the margins with a high speed drill and filling the space with bone cement was performed. Outcomes: At latest follow-up 10 years after surgery, no recurrence was observed. Lessons: An individual therapy for surgical treatment of IIFS is recommended. This comprises marginal resection in instead of the golden standard “wide resection” in selected cases.

The correct cup position in total hip arthroplasty (THA) is usually assessed on anteroposterior low centered pelvic radiographs, harboring the risk of misinterpretation due to projection of a three-dimensional geometry on a two-dimensional plane. In the current study, we evaluate the effect of this parallax effect on the cup inclination and anteversion in THA. In the course of a prospective clinical trial, 116 standardized low centered pelvic radiographs, as routinely obtained after THA, were evaluated regarding the impact of central beam deviation on the cup inclination and anteversion angles. Measurements of the horizontal and vertical beam offset with two different methods of parallax correction were compared with each other. Furthermore, the effect of parallax correction on the accuracy ofmeasuring the cup position was investigated. The mean difference between the two parallax correction methods was 0.2° ± 0.1° (from 0° to 0.4°) for the cup inclination and 0.1° ± 0.1° (from −0.1° to 0.2°) for the anteversion. For a typically intended cup position of a 45° inclination and 15° anteversion, the parallax effect led to a mean error of −1.5° ± 0.3° for the inclination and 0.6° ± 1.0° for the anteversion. Central beam deviation resulted in a projected higher cup inclination up to 3.7°, and this effect was more prominent in cups with higher anteversion. In contrast, the projected inclination decreased due to the parallax effect up to 3.2°, especially in cups with high inclination. The parallax effect on routinely obtained low centered pelvic radiographs is low and not clinically relevant due to the compensating effect of simultaneous medial and caudal central beam deviation.

Introduction Avascular osteonecrosis of the femoral head (AVN) is a widespread disease affecting mostly young and active people, often exacerbating in progressive stages, ending in joint replacement. The most common joint preserving operative therapy for early stages is core decompression (CD), optional with cancellous bone grafting (CBG). For success it is vital that the necrotic area is hit and the sclerotic rim is broken by drilling into the defect zone to relieve intraosseous pressure. The aim of this study was to investigate if both techniques are precise enough to hit the center of the necrosis and if there is a difference in precision between drilling with small pins (CD) and the trephine (CBG). Patients and methods 10 patients underwent CD, 12 patients CBG with conventional C-arm imaging. Postoperatively 3D MRI reconstructions of the necrotic area and the drilling channels were compared. The deviation of the drilling channel from the center of the necrotic area was measured. PROMs (HHS, HOOS, EQ-5D, SF-36) were evaluated to compare the clinical success of these procedures. Results Neither with CD nor with CBG the defect zone was missed. The drilling precision of both procedures did not differ significantly: distance to center 3.58 mm for CD (range 0.0–14.06, SD 4.2) versus 3.91 mm for CBG (range 0.0–15.27, SD 4.7). PROMs showed no significant difference. Conclusion Concerning the most important difference between the two procedures—the surgical higher demanding technique of CBG—we suggest applying the less invasive technique of CD alone.

“Safe zones” for cup position are currently being investigated in total hip arthroplasty (THA). This study aimed to evaluate the impact of bony impingement on the safe zone and provide recommendations for cup position in THA. CT scans were performed on 123 patients who underwent a cementless THA. Using the implant data and bone morphology from the CT scans, an impingement detection algorithm simulating range of motion (ROM) determined the presence of prosthetic and/or bony impingement. An impingement-free zone of motion was determined for each patient. These zones were then compared across all patients to establish an optimized impingement-free “safe zone”. Bony impingement reduced the impingement-free zone of motion in 49.6% (61/123) of patients. A mean reduction of 23.4% in safe zone size was observed in relation to periprosthetic impingement. The superposition of the safe zones showed the highest probability of impingement-free ROM with cup position angles within 40–50° of inclination and 20–30° of anteversion in relation to the applied cup and stem design of this study. Virtual ROM simulations identified bony impingement at the anterosuperior acetabular rim for internal rotation at 90° of flexion and at the posteroinferior rim for adduction as the main reasons for bony impingement.

Purpose: The Hospital Frailty Risk Score (HFRS) is derived from routinely collected data and validated as a geriatric risk stratification tool. This study aimed to evaluate the utility of the HFRS as a predictor for postoperative adverse events in spine surgery. Methods: In this retrospective analysis of 2042 patients undergoing spine surgery at a university spine center between 2011 and 2019, HFRS was calculated for each patient. Multivariable logistic regression models were used to assess the relationship between the HFRS and postoperative adverse events. Adverse events were compared between patients with high or low frailty risk. Results: Patients with intermediate or high frailty risk showed a higher rate of reoperation (19.7% vs. 12.2%, p < 0.01), surgical site infection (3.4% vs. 0.4%, p < 0.001), internal complications (4.1% vs. 1.1%, p < 0.01), Clavien–Dindo IV complications (8.8% vs. 3.4%, p < 0.001) and transfusion (10.9% vs. 1.5%, p < 0.001). Multivariable logistic regression analyses revealed a high HFRS as independent risk factor for reoperation [odds ratio (OR) = 1.1; 95% confidence interval (CI) 1.0–1.2], transfusion (OR = 1.3; 95% CI 1.2–1.4), internal complications (OR = 1.2; 95% CI 1.1–1.3), surgical site infections (OR = 1.3; 95% CI 1.2–1.5) and other complications (OR = 1.3; 95% CI 1.2–1.4). Conclusion: The HFRS can predict adverse events and is an easy instrument, fed from routine hospital data. By identifying risk patients at an early stage, the individual patient risk could be minimized, which leads to less complications and lower costs. Level of evidence: Level III – retrospective cohort study Trial registration: The study was approved by the local ethics committee (20-1821-104) of the University of Regensburg in February 2020.