Prinzipien der Defektrekonstruktion nach weiter Resektion primärer maligner Knochentumoren des Fersenbeins

Primäre maligne Knochentumoren sind eine seltene und heterogene Gruppe von bösartigen Neoplasien. Die häufigsten Tumorentitäten der Knochensarkome sind das Osteosarkom, Chondrosarkom und Ewingsarkom. Der Rückfuss stellt mit Talus und Calcaneus bei Befall von Fuß und Sprunggelenk die häufigste Lokalisation dar. Die chirurgische Resektion ist die Hauptstütze der Behandlung eines lokalisierten Knochentumors, wobei je nach histologischem Subtyp, Grading und Lage des Tumors verschiedene Techniken zur Verfügung stehen. Bei schlecht differenzierten Knochensarkomen (≥ G2) ist die weite Resektion essenziell um das Tumorleiden lokal wie auch systemisch erfolgreich behandeln zu können. Die Rekonstruktion der dadurch entstehenden Defektsituationen stellt aufgrund der Seltenheit der Erkrankung, Heterogenität des Tumorbefalls und individueller Patientenfaktoren eine Herausforderung an den behandelnden Chirurgen dar. Während für die Rekonstruktion nach Resektion von Knochensarkomen der häufigsten Lokalisationen (distales Femur, proximale Tibia, proximaler Humerus) bewährte Therapiekonzepte existieren (z.B. modulare Megaprothese, Umkehrplastik), scheinen diese an Fuß und Sprunggelenk weniger etabliert zu sein. Möglichkeiten rekonstruktiver Verfahren nach Calcanektomie sind vielfältig, aufgrund ihrer Seltenheit in der Literatur meist jedoch lediglich in Form von Einzelfallberichten publiziert. Prinzipiell kann die Defektrekonstruktion in biologische (autolog oder allogen) und alloarthroplastische Verfahren unterteilt werden. Des Weiteren besteht die Möglichkeit einer Resektionsarthroplastik nach partieller oder totaler Calcanectomie mit Transposition der Achillessehne auf den Processus posterior tali. Ziel dieses Beitrags ist es, die Prinzipien der calcanearen Defektrekonstruktion nach weiter Tumorresektion anhand einer Literaturübersicht darzustellen und mögliche Problematiken der unterschiedlichen Rekonstruktionsarten anhand von beispielhaften Fallberichten aufzuzeigen.[Principles of defect reconstruction after wide resection of primary malignant bone tumours of the calcaneus] Primary malignant bone tumors are a rare and heterogeneous group of malignancies. The most common tumor entities of bone sarcomas are osteosarcoma, chondrosarcoma, and ewing's sarcoma; with talus and calcaneus, the hindfoot represents the most common localization affected. Surgical resection is the mainstay of treatment for localized bone tumor, with various techniques available depending on the histologic type, grading, and location of the tumor. In poorly differentiated bone sarcomas (≥ G2), wide resection is essential to successfully treat the tumor disease locally as well as systemically. Reconstruction of the resulting defect situations poses a challenge to the treating surgeon due to the rarity of the disease, heterogeneity of tumor involvement, and individual patient factors. While proven therapeutic concepts exist for reconstruction after resection of bone sarcomas of the most common localisations (distal femur, proximal tibia, proximal humerus) e.g. with modular megaprosthesis or rotationplasty, these seem to be less established for the foot and ankle. Reconstructive procedures after calcanectomy are manifold, but due to their rarity, they are mostly published as case reports. In principle, defect reconstruction can be divided into biological (autologous or allogenic) and alloarthroplastic procedures. Moreover, we will discuss the option of a resectionarthroplasty after partial or total calcanectomy with transposition of the Achilles tendon. This article aims to present the principles of calcaneal defect reconstruction after extensive tumor resection based on a literature review and to highlight possible problems of different types of reconstruction with exemplary case reports

Correlation of radiographic variables to guide safe implant positioning during acetabular surgery and hip replacement: a retrospective observational study

Abstract Background Knowledge of periacetabular anatomy is crucial for prosthetic cup placement in total hip arthroplasty and for screw placement in anterior fixation with acetabular fractures. It is known that degree of hip dysplasia correlates with medial bone stock and that medial bone stock shows a weak correlation to Lequesne’s acetabular index (AI). Aim of this study was to investigate a possible correlation between AI and the newly proposed medial safe zone. Methods AI and the medial save zone were measured on 419 hips using a computed-tomography scan of the pelvis. AI was assessed on a 2D reconstructed anterior-posterior view of the pelvis using VOXAR™. Correlation was measured using the Pearson correlation coefficient. Results Mean AI was 4.2 degrees (SD 4.9 degrees). Mean medial safe zone was 8.1 mm (SD 1.9 mm). There was a significant correlation between AI and medial save space with a Pearson correlation coefficient r = 0.33 (p = .001). Conclusion There is a weak correlation between AI and medial safe zone. AI should not be used to predict medial safe zone. Due to the weakness in correlation AI is not suited for predicting medial safe zone. However, a low or negative AI can be a warning sign for less medial safe zone, prompting surgeons to take care when reaming in THA or placing periacetabular screws

Local effect of zoledronic acid on new bone formation in posterolateral spinal fusion with demineralized bone matrix in a murine model

BACKGROUND: Posterolateral spinal fusion is a common orthopaedic surgery performed to treat degenerative and traumatic deformities of the spinal column. In posteriolateral spinal fusion, different osteoinductive demineralized bone matrix products have been previously investigated. We evaluated the effect of locally applied zoledronic acid in combination with commercially available demineralized bone matrix putty on new bone formation in posterolateral spinal fusion in a murine in vivo model. METHODS: A posterolateral sacral spine fusion in murine model was used to evaluate the new bone formation. We used the sacral spine fusion model to model the clinical situation in which a bone graft or demineralized bone matrix is applied after dorsal instrumentation of the spine. In our study, group 1 received decortications only (n = 10), group 2 received decortication, and absorbable collagen sponge carrier, group 3 received decortication and absorbable collagen sponge carrier with zoledronic acid in dose 10 µg, group 4 received demineralized bone matrix putty (DBM putty) plus decortication (n = 10), and group 5 received DBM putty, decortication and locally applied zoledronic acid in dose 10 µg. Imaging was performed using MicroCT for new bone formation assessment. Also, murine spines were harvested for histopathological analysis 10 weeks after surgery. RESULTS: The surgery performed through midline posterior approach was reproducible. In group with decortication alone there was no new bone formation. Application of demineralized bone matrix putty alone produced new bone formation which bridged the S1-S4 laminae. Local application of zoledronic acid to demineralized bone matrix putty resulted in significant increase of new bone formation as compared to demineralized bone matrix putty group alone. CONCLUSIONS: A single local application of zoledronic acid with DBM putty during posterolateral fusion in sacral murine spine model increased significantly new bone formation in situ in our model. Therefore, our results justify further investigations to potentially use local application of zoledronic acid in future clinical studies

The influence of obesity and gender on outcome after reversed L-shaped osteotomy for hallux valgus

BACKGROUND Hallux valgus deformity (HV) affects around every fourth individual, and surgical treatment is performed in every thousandth person. There is an ongoing quest for the best surgical management and reduction of undesirable outcomes. The aim was to explore associations of obesity and gender with radiological and clinical outcome after reversed L-shaped osteotomy (ReveL) for HV. MATERIALS AND METHODS This study was carried out in a retrospective cohort design at a single University Hospital in Switzerland between January 2004 and December 2013. It included adult patients treated with ReveL for HV. The primary exposure was body mass index (BMI) at the time of ReveL. The secondary exposure was gender. The primary outcome was radiological relapse of HV (HV angle [HVA] > 15 degrees [°]) at the last follow-up. Secondary outcomes were improvable patient satisfaction, complication, redo surgery, and optional hardware removal. Logistic regression analysis adjusted for confounders. RESULTS The median weight, height, and BMI were 66.0 (interquartile range [IQR] 57.0-76.0) kilograms (kg), 1.65 (IQR 1.60-1.71) metres (m), and 24.0 (IQR 21.3-27.8) kg/m$^{2}$. Logistic regression analysis did not show associations of relapse with BMI, independent of age, gender, additional technique, and preoperative HVA (adjusted odds ratio [OR$_{adjusted}$] = 1.10 [95% (%) confidence interval (CI) = 0.70-1.45], p = 0.675). Relapse was 91% more likely in males (OR$_{adjusted}$ = 1.91 [95% CI = 1.19-3.06], p = 0.007). Improvable satisfaction was 79% more likely in males (OR$_{adjusted}$ = 1.79 [CI = 1.04-3.06], p = 0.035). Hardware removal was 47% less likely in males (OR$_{adjusted}$ = 0.53 [95% CI 0.30-0.94], p = 0.029). CONCLUSIONS In this study, obesity was not associated with unsatisfactory outcomes after ReveL for HV. This challenges the previous recommendation that preoperative weight loss may be necessary for a successful surgical treatment outcome. Males may be informed about potentially higher associations with unfavourable outcomes. Due to the risk of selection bias and lack of causality, findings may need to be confirmed with clinical trials

Outcomes of management of proximal humeral fractures with patient-specific, evidence-based treatment algorithms

Background: Previous studies have identified risk factors for different types of treatment of proximal humeral fracture (PHF) and allowed the development of a patient-specific, evidence-based treatment algorithm with the potential of improving overall outcomes and reducing complications. The purpose of this study was to evaluate the results and complications of treating PHF using this algorithmic approach. Methods: All patients with isolated PHF between 2014 and 2017 were included and prospectively followed. The initial treatment algorithm (Version 1 [V1]) based on patients' functional needs, bone quality, and type of fracture was refined after 2 years (Version 2 [V2]). Adherence to protocol, clinical outcomes, and complications were analyzed at a 1-year follow-up. Results: The study included 334 patients (mean age, 66 years; 68% female): 226 were treated nonoperatively; 65, with open reduction and internal fixation (ORIF); 39, with reverse total shoulder arthroplasty (RTSA); and 4, with hemiarthroplasty. At 1 year, the preinjury EuroQol 5-Dimension (EQ-5D) values were regained (0.88 and 0.89, respectively) and the mean relative Constant Score (CS) and Subjective Shoulder Value (SSV) (and standard deviation [SD]) were 96% +/- 21% and 85% +/- 16%. Overall complications and revision rates were 19% and 13%. Treatment conforming to the algorithm outperformed non-conforming treatment with respect to relative CS (97% versus 88%, p = 0.016), complication rates (16.3% versus 30.8%, p = 0.014), and revision rates (10.6% versus 26.9%, p < 0.001). Conclusions: Treating PHF using a patient-specific, evidence-based algorithm restored preinjury quality of life as measured with the EQ-5D and approximately 90% normal shoulders as measured with the relative CS and the SSV. Adherence to the treatment algorithm was associated with significantly better clinical outcomes and substantially reduced complication and revision rates

The impact of biopsy sampling errors and the quality of surgical margins on local recurrence and survival in chondrosarcoma

Purpose To examine the frequency of computed tomography (CT)-guided biopsy sampling errors in chondrosarcomas, as well as the impact of these errors and the achieved surgical margins on local recurrence-free survival (LRFS) and disease-specific survival (DSS). Material and methods A total of 68 consecutive patients treated for chondrosarcoma from 2000-2015 were retrospectively reviewed with a minimum follow-up duration of 2 years. Results The primary location was at the extremities in 46 patients (67.6%) and at the axial skeleton in 22 patients (32.4%). Seven patients underwent planned intralesional curettage. Surgical margins were assessed in the remaining 53 patients and included 21 wide (39.6%), 25 marginal (47.1%), and seven intralesional (13.2%) resections. Biopsy sampling errors occurred in ten patients (14.7%). LRFS was 82.2±7.8% at 5 years and 76.9±7.8% at 10 years. An intact anatomical barrier was associated with the most preferable LRFS of 89±10.5% after 10 years. DSS was 79.2±8.5% at 5 years and 75.5±6.4% at 10 years. The metric distance of the surgical margin and the presence of a biopsy sampling error did not affect either LRFS or DSS. Conclusion Even though histological grading in chondrosarcoma is difficult, sampling errors in preoperative biopsies are relatively rare and do not adversely affect outcomes. The presence of an anatomical barrier has a greater impact on LRFS than the metric distance of the surgical margins

Diurnal T2-changes of the intervertebral discs of the entire spine and the influence of weightlifting

The purpose was to study if (1) diurnal changes occur in the entire spine and if (2) intervertebral discs (IVDs) of weightlifters (WL) have decreased baseline T2-values in the morning as well as (3) increased diurnal changes throughout the day. This prospective cohort study investigated healthy volunteers between 2015 and 2017. WL were required to have participated in weightlifting ≥ 4×/week for ≥ 5 years, while non-weightlifters (NWL) were limited to < 2×/week for ≥ 5 years. Both groups underwent magnetic resonance imaging (MRI) of the entire spine in the morning and evening. WL were requested to perform weightlifting in-between imaging. IVD regions of interest (nucleus pulposus) were defined and T2-maps were measured. Analysis consisted of unpaired t-test, paired t-test, propensity-score matching (adjusting for age and sex), and Pearson correlation. Twenty-five individuals (15 [60.0%] males) with a mean age of 29.6 (standard deviation [SD 6.9]) years were analyzed. Both groups (WL: n = 12 versus [vs.] NWL: n = 13) did not differ demographic characteristics. Mean IVD T2-values of all participants significantly decreased throughout the day (95.7 [SD 15.7] vs. 86.4 [SD 13.9] milliseconds [ms]) in IVDs of the cervical (71.8 [SD 13.4] vs. 64.4 [SD 14.1] ms), thoracic (98.8 [SD 19.9] vs. 88.6 [SD 16.3] ms), and lumbar (117.0 [SD 23.7] vs. 107.5 [SD 21.6] ms) spine (P < 0.001 each). There were no differences between both groups in the morning (P = 0.635) and throughout the day (P = 0.681), even after adjusting for confounders. It can be concluded that diurnal changes of the IVDs occurred in the entire (including cervical and thoracic) spine. WL and NWL showed similar morning baseline T2-values and diurnal changes. Weightlifting may not negatively affect IVDs chronically or acutely