Internal hemipelvectomy without reconstruction of the pelvis is a viable treatment for pelvic sarcoma; however, the time it takes to return to excellent function is quite variable. Some patients require greater time and rehabilitation than others. To determine if psoas muscle recovery is associated with changes in ambulatory function, we retrospectively evaluated psoas muscle size and limb-length discrepancy (LLD) before and after treatment and their correlation with objective functional outcomes. T1-weighted MR images were evaluated at three intervals for 12 pelvic sarcoma patients following interval hemipelvectomy without reconstruction. Correlations between the measured changes and improvements in Timed Up and Go test (TUG) and gait speed outcomes were assessed both independently and using a stepwise multivariate regression model.Aims
Methods
Endoprosthetic reconstruction following distal femur tumour resection has been widely advocated. In this paper, we present the design of an uncemented endoprosthesis system featuring a short, curved stem, with the goal of enhancing long-term survivorship and functional outcomes. This study involved patients who underwent implantation of an uncemented distal femoral endoprosthesis with a short and curved stem between 2014 and 2019. Functional outcomes were assessed using the 1993 version of the Musculoskeletal Tumour Society (MSTS-93) score. Additionally, we quantified five types of complications and assessed osseointegration radiologically. The survivorship of the endoprosthesis was evaluated according to two endpoints. A total of 134 patients with a median age of 26 years (IQR 16 to 41) were included in our study. The median follow-up time was 61 months (IQR 56 to 76), and the median functional MSTS-93 was 83% (IQR 73 to 91) postoperatively.Aims
Methods
Orthopaedic and reconstructive surgeons are faced with large defects after the resection of malignant tumours of the sacrum. Spinopelvic reconstruction is advocated for resections above the level of the S1 neural foramina or involving the sacroiliac joint. Fixation may be augmented with either free vascularized fibular flaps (FVFs) or allograft fibular struts (AFSs) in a cathedral style. However, there are no studies comparing these reconstructive techniques. We reviewed 44 patients (23 female, 21 male) with a mean age of 40 years (SD 17), who underwent en bloc sacrectomy for a malignant tumour of the sacrum with a reconstruction using a total (n = 20), subtotal (n = 2), or hemicathedral (n = 25) technique. The reconstructions were supplemented with a FVF in 25 patients (57%) and an AFS in 19 patients (43%). The mean length of the strut graft was 13 cm (SD 4). The mean follow-up was seven years (SD 5).Aims
Methods
Accurate estimations of the risk of fracture due to metastatic bone disease in the femur is essential in order to avoid both under-treatment and over-treatment of patients with an impending pathological fracture. The purpose of the current retrospective in vivo study was to use CT-based finite element analyses (CTFEA) to identify a clear quantitative differentiating factor between patients who are at imminent risk of fracturing their femur and those who are not, and to identify the exact location of maximal weakness where the fracture is most likely to occur. Data were collected on 82 patients with femoral metastatic bone disease, 41 of whom did not undergo prophylactic fixation. A total of 15 had a pathological fracture within six months following the CT scan, and 26 were fracture-free during the five months following the scan. The Mirels score and strain fold ratio (SFR) based on CTFEA was computed for all patients. A SFR value of 1.48 was used as the threshold for a pathological fracture. The sensitivity, specificity, positive, and negative predicted values for Mirels score and SFR predictions were computed for nine patients who fractured and 24 who did not, as well as a comparison of areas under the receiver operating characteristic curves (AUC of the ROC curves).Aims
Methods
To assess the accuracy of patient-specific instruments (PSIs) CT scans were obtained from five female cadaveric pelvises. Five osteotomies were designed using Mimics software: sacroiliac, biplanar supra-acetabular, two parallel iliopubic and ischial. For cases of the left hemipelvis, PSIs were designed to guide standard oscillating saw osteotomies and later manufactured using 3D printing. Osteotomies were performed using the standard manual technique in cases of the right hemipelvis. Post-resection CT scans were quantitatively analysed. Student’s Objectives
Methods
Instability of the hip is the most common mode of failure after
reconstruction with a proximal femoral arthroplasty (PFA) using
an endoprosthesis after excision of a tumour. Small studies report
improved stability with capsular repair of the hip and other techniques,
but these have not been investigated in a large series of patients.
The aim of this study was to evaluate variables associated with
the patient and the operation that affect post-operative stability.
We hypothesised an association between capsular repair and stability. In a retrospective cohort study, we identified 527 adult patients
who were treated with a PFA for tumours. Our data included demographics,
the pathological diagnosis, the amount of resection of the abductor
muscles, the techniques of reconstruction and the characteristics
of the implant. We used regression analysis to compare patients
with and without post-operative instability.Aims
Patients and Methods
Massive endoprostheses rely on extra-cortical bone bridging (ECBB)
to enhance fixation. The aim of this study was to investigate the
role of selective laser sintered (SLS) porous collars in augmenting
the osseointegration of these prostheses. The two novel designs of porous SLS collars, one with small pores
(Ø700 μm, SP) and one with large pores (Ø1500 μm, LP), were compared
in an ovine tibial diaphyseal model. Osseointegration of these collars
was compared with that of a clinically used solid, grooved design
(G). At six months post-operatively, the ovine tibias were retrieved and
underwent radiological and histological analysis.Aims
Materials and Methods
The most concerning infection of allografts and operative procedures
is methicillin resistant An iontophoresis cell was set up with varying concentrations
of Vancomycin within the medulla of a section of sheep tibia, sealed
from an external saline solution. The cell was run for varying times,
Vancomycin concentrations and voltages, to gain information on optimisation
of conditions for impregnating the graft. Each graft was then sectioned
and dust ground from the exposed surface. The dust was serially
washed to extract the Vancomycin and concentrations measured and
plotted for all variables tested.Objectives
Methods
Previously, we showed that case-specific non-linear
finite element (FE) models are better at predicting the load to failure
of metastatic femora than experienced clinicians. In this study
we improved our FE modelling and increased the number of femora
and characteristics of the lesions. We retested the robustness of
the FE predictions and assessed why clinicians have difficulty in
estimating the load to failure of metastatic femora. A total of
20 femora with and without artificial metastases were mechanically
loaded until failure. These experiments were simulated using case-specific
FE models. Six clinicians ranked the femora on load to failure and
reported their ranking strategies. The experimental load to failure
for intact and metastatic femora was well predicted by the FE models (R2 =
0.90 and R2 = 0.93, respectively). Ranking metastatic
femora on load to failure was well performed by the FE models (τ =
0.87), but not by the clinicians (0.11 <
τ <
0.42). Both the
FE models and the clinicians allowed for the characteristics of
the lesions, but only the FE models incorporated the initial bone
strength, which is essential for accurately predicting the risk
of fracture. Accurate prediction of the risk of fracture should
be made possible for clinicians by further developing FE models.
Pathological fractures in children can occur
as a result of a variety of conditions, ranging from metabolic diseases and
infection to tumours. Fractures through benign and malignant bone
tumours should be recognised and managed appropriately by the treating
orthopaedic surgeon. The most common benign bone tumours that cause pathological
fractures in children are unicameral bone cysts, aneurysmal bone
cysts, non-ossifying fibromas and fibrous dysplasia. Although pathological
fractures through a primary bone malignancy are rare, these should
be recognised quickly in order to achieve better outcomes. A thorough
history, physical examination and review of plain radiographs are
crucial to determine the cause and guide treatment. In most benign
cases the fracture will heal and the lesion can be addressed at
the time of the fracture, or after the fracture is healed. A step-wise
and multidisciplinary approach is necessary in caring for paediatric
patients with malignancies. Pathological fractures do not have to
be treated by amputation; these fractures can heal and limb salvage
can be performed when indicated.
We retrospectively evaluated 18 patients with a mean age of 37.3 years (14 to 72) who had undergone pelvic reconstruction stabilised with a non-vascularised fibular graft after resection of a primary bone tumour. The mean follow-up was 10.14 years (2.4 to 15.7). The mean Musculoskeletal Tumor Society Score was 76.5% (50% to 100%). Primary union was achieved in the majority of reconstructions within a mean of 22.9 weeks (7 to 60.6). The three patients with delayed or nonunion all received additional therapy (chemotherapy/radiation) (p = 0.0162). The complication rate was comparable to that of other techniques described in the literature. Non-vascularised fibular transfer to the pelvis is a simpler, cheaper and quicker procedure than other currently described techniques. It is a biological reconstruction with good results and a relatively low donor site complication rate. However, adjuvant therapy can negatively affect the outcome of such grafts.
