This study aimed to compare the performance of survival prediction models for bone metastases of the extremities (BM-E) with pathological fractures in an Asian cohort, and investigate patient characteristics associated with survival. This retrospective cohort study included 469 patients, who underwent surgery for BM-E between January 2009 and March 2022 at a tertiary hospital in South Korea. Postoperative survival was calculated using the PATHFx3.0, SPRING13, OPTIModel, SORG, and IOR models. Model performance was assessed with area under the curve (AUC), calibration curve, Brier score, and decision curve analysis. Cox regression analyses were performed to evaluate the factors contributing to survival.Aims
Methods
Hospital case volume is shown to be associated with postoperative outcomes in various types of surgery. However, conflicting results of volume-outcome relationship have been reported in hip fracture surgery. This retrospective cohort study aimed to evaluate the association between hospital case volume and postoperative outcomes in patients who had hip fracture surgery. We hypothesized that higher case volume would be associated with lower risk of in-hospital and one-year mortality after hip fracture surgery. Data for all patients who underwent surgery for hip fracture from January 2008 to December 2016 were extracted from the Korean National Healthcare Insurance Service database. According to mean annual case volume of surgery for hip fracture, hospitals were classified into very low (< 30 cases/year), low (30 to 50 cases/year), intermediate (50 to 100 cases/year), high (100 to 150 cases/year), or very high (> 150 cases/year) groups. The association between hospital case volume and in-hospital mortality or one-year mortality was assessed using the logistic regression model to adjust for age, sex, type of fracture, type of anaesthesia, transfusion, comorbidities, and year of surgery.Aims
Methods
Mobile-bearing unicompartmental knee arthroplasty (UKA) with a flat tibial plateau has not performed well in the lateral compartment, leading to a high rate of dislocation. For this reason, the Domed Lateral UKA with a biconcave bearing was developed. However, medial and lateral tibial plateaus have asymmetric anatomical geometries, with a slightly dished medial and a convex lateral plateau. Therefore, the aim of this study was to evaluate the extent at which the normal knee kinematics were restored with different tibial insert designs using computational simulation. We developed three different tibial inserts having flat, conforming, and anatomy-mimetic superior surfaces, whereas the inferior surface in all was designed to be concave to prevent dislocation. Kinematics from four male subjects and one female subject were compared under deep knee bend activity.Aims
Methods
For paediatric and adolescent patients with growth potential, preservation of the physiological joint by transepiphyseal resection (TER) of the femur confers definite advantages over arthroplasty procedures. We hypothesized that the extent of the tumour and changes in its extent after neoadjuvant chemotherapy are essential factors in the selection of this procedure, and can be assessed with MRI. The oncological and functional outcomes of the procedure were reviewed to confirm its safety and efficacy. We retrospectively reviewed 16 patients (seven male and nine female, mean age 12.2 years (7 to 16)) with osteosarcoma of the knee who had been treated by TER. We evaluated the MRI scans before and after neoadjuvant chemotherapy for all patients to assess the extent of the disease and the response to treatment.Aims
Methods
Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated.Aims
Methods
Unicompartmental knee arthroplasty (UKA) is an alternative to total knee arthroplasty with isolated medial or lateral compartment osteoarthritis. However, polyethylene wear can significantly reduce the lifespan of UKA. Different bearing designs and materials for UKA have been developed to change the rate of polyethylene wear. Therefore, the objective of this study is to investigate the effect of insert conformity and material on the predicted wear in mobile-bearing UKA using a previously developed computational wear method. Two different designs were tested with the same femoral component under identical kinematic input: anatomy mimetic design (AMD) and conforming design inserts with different conformity levels. The insert materials were standard or crosslinked ultra-high-molecular-weight polyethylene (UHMWPE). We evaluated the contact pressure, contact area, wear rate, wear depth, and volumetric wear under gait cycle loading conditions.Objectives
Methods
Preservation of both anterior and posterior cruciate ligaments in total knee arthroplasty (TKA) can lead to near-normal post-operative joint mechanics and improved knee function. We hypothesised that a patient-specific bicruciate-retaining prosthesis preserves near-normal kinematics better than standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining prostheses in TKA. We developed the validated models to evaluate the post-operative kinematics in patient-specific bicruciate-retaining, standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under gait and deep knee bend loading conditions using numerical simulation.Objectives
Methods
We evaluated the accuracy of augmented reality (AR)-based navigation assistance through simulation of bone tumours in a pig femur model. We developed an AR-based navigation system for bone tumour resection, which could be used on a tablet PC. To simulate a bone tumour in the pig femur, a cortical window was made in the diaphysis and bone cement was inserted. A total of 133 pig femurs were used and tumour resection was simulated with AR-assisted resection (164 resection in 82 femurs, half by an orthropaedic oncology expert and half by an orthopaedic resident) and resection with the conventional method (82 resection in 41 femurs). In the conventional group, resection was performed after measuring the distance from the edge of the condyle to the expected resection margin with a ruler as per routine clinical practice.Objectives
Methods
Deformity of the proximal femur in fibrous dysplasia
leads to deviation of the mechanical axis of the hip, which may lead
to the development of secondary osteoarthritis (OA). This study
investigated the prevalence and predisposing factors for the development
of OA in patients with fibrous dysplasia of the proximal femur.
We reviewed the records of 209 patients from our institutional database
with fibrous dysplasia of the proximal femur, investigating possible predisposing
factors including patient demographics, the extent of the coxa vara
deformity, the presence of peri-articular disease, and the overall
burden of skeletal disease. Of the 209 patients, 24 (12%) had radiological
evidence of OA in the ipsilateral hip. The prevalence was significantly
higher in patients with polyostotic fibrous dysplasia compared with
those with monostotic disease (p <
0.001). In a subgroup analysis of
patients with polyostotic disease, the extent of deformity (quantified
using the neck–shaft angle), and the presence of peri-articular
disease (whether in the head of the femur or the acetabulum) were
significant predictors of osteoarthritis (neck–shaft angle likelihood
ratio (LR) = 0.847 per 1° increase, p = 0.004; presence of lesion
in the head of the femur LR = 9.947, p = 0.027; presence of lesion
in the acetabulum LR = 11.231, p = 0.014). Our data suggest that patients with polyostotic fibrous dysplasia
have a high risk of developing secondary OA of the hips. This risk
is higher in patients with peri-articular disease, and those with
a more severe deformity of proximal femur. Cite this article:
Cancellous allograft bone chips are commonly
used in the reconstruction of defects in bone after removal of benign tumours.
We investigated the MRI features of grafted bone chips and their
change over time, and compared them with those with recurrent tumour.
We retrospectively reviewed 66 post-operative MRIs from 34 patients
who had undergone curettage and grafting with cancellous bone chips
to fill the defect after excision of a tumour. All grafts showed
consistent features at least six months after grafting: homogeneous
intermediate or low signal intensities with or without scattered
hyperintense foci (speckled hyperintensities) on T1 images; high
signal intensities with scattered hypointense foci (speckled hypointensities)
on T2 images, and peripheral rim enhancement with or without central
heterogeneous enhancements on enhanced images. Incorporation of
the graft occurred from the periphery to the centre, and was completed
within three years. Recurrent lesions consistently showed the same signal
intensities as those of pre-operative MRIs of the primary lesions.
There were four misdiagnoses, three of which were chondroid tumours. We identified typical MRI features and clarified the incorporation
process of grafted cancellous allograft bone chips. The most important
characteristics of recurrent tumours were that they showed the same
signal intensities as the primary tumours. It might sometimes be
difficult to differentiate grafted cancellous allograft bone chips
from a recurrent chondroid tumour. Cite this article:
Monostotic fibrous dysplasia of the proximal
femur has a variable clinical course, despite its reported limited tendency
to progress. We investigated the natural history and predisposing factors
for progression of dysplasia in a group of 76 patients with a mean
follow-up of 8.5 years (2.0 to 15.2). Of these, 31 (41%) presented
with an asymptomatic incidental lesion while 45 (59%) presented
with pain or a pathological fracture. A group of 23 patients (30%)
underwent early operative treatment for pain (19: 25%) or pathological
fracture (4: 5%). Of the 53 patients who were initially treated non-operatively,
45 (85%) remained asymptomatic but eight (15%) needed surgery because
of pain or fracture. The progression-free survival of the observation
group was 81% ( The risk of experiencing pain or pathological fracture is considerable
in monostotic fibrous dysplasia of the proximal femur. Patients
presenting with pain, a limp or radiological evidence of microfracture
have a high chance of needing surgical treatment. Cite this article:
We evaluated the oncological and functional outcome
of 18 patients, whose malignant bone tumours were excised with the
assistance of navigation, and who were followed up for more than
three years. There were 11 men and seven women, with a mean age
of 31.8 years (10 to 57). There were ten operations on the pelvic
ring and eight joint-preserving limb salvage procedures. The resection
margins were free of tumour in all specimens. The tumours, which
were stage IIB in all patients, included osteosarcoma, high-grade
chondrosarcoma, Ewing’s sarcoma, malignant fibrous histiocytoma
of bone, and adamantinoma. The overall three-year survival rate
of the 18 patients was 88.9% (95% confidence interval (CI) 75.4
to 100). The three-year survival rate of the patients with pelvic malignancy
was 80.0% (95% CI 55.3 to 100), and of the patients with metaphyseal
malignancy was 100%. The event-free survival was 66.7% (95% CI 44.9
to 88.5). Local recurrence occurred in two patients, both of whom
had a pelvic malignancy. The mean Musculoskeletal Tumor Society
functional score was 26.9 points at a mean follow-up of 48.2 months
(22 to 79). We suggest that navigation can be helpful during surgery for
musculoskeletal tumours; it can maximise the accuracy of resection
and minimise the unnecessary sacrifice of normal tissue by providing
precise intra-operative three-dimensional radiological information.
This study evaluates factors related to myelopathic
symptoms in patients with ossification of the posterior longitudinal
ligament (OPLL). A total of 87 patients with OPLL were included.
Of these, 53 (Group I) had no symptoms or presented with neck pain
and radiculopathy and 34 (Group II) had myelopathic symptoms. Gender, age,
and history of trauma were evaluated in the two groups. The range
of movement of the cervical spine was measured using plain radiographs.
The number of involved segments, type of OPLL, and maximal compression ratio
were analysed using CT and signal change in the spinal cord was
evaluated using MRI. The patients’ age was found to be significant (p = 0.001). No
difference was found between gender and the range of movement in
the two groups. The maximum compression of the spinal canal showed
a difference (p = 0.03). The signal change of the spinal cord was
different between the two groups. In patients with OPLL of the cervical
spine, myelopathic symptoms are not related to the range of movement
or the number of involved segments.
Medial open-wedge high tibial osteotomy has been gaining popularity in recent years, but adequate supporting material is required in the osteotomy gap for early weight-bearing and rapid union. The purpose of this study was to investigate whether the implantation of a polycaprolactone-tricalcium phosphate composite scaffold wedge would enhance healing of the osteotomy in a micro pig model. We carried out open-wedge high tibial osteotomies in 12 micro pigs aged from 12 to 16 months. A scaffold wedge was inserted into six of the osteotomies while the other six were left open. Bone healing was evaluated after three and six months using plain radiographs, CT scans, measurement of the bone mineral density and histological examination. Complete bone union was obtained at six months in both groups. There was no collapse at the osteotomy site, loss of correction or failure of fixation in either group. Staining with haematoxylin and eosin demonstrated that there was infiltration of new bone tissue into the macropores and along the periphery of the implanted scaffold in the scaffold group. The CT scans and measurement of the bone mineral density showed that at six months specimens in the scaffold group had a higher bone mineral density than in the control group, although the implantation of the polycaprolactone-tricalcium phosphate composite scaffold wedge did not enhance healing of the osteotomy.
Skeletal metastases from hepatocellular carcinoma are highly destructive vascular lesions which severely reduce the quality of life. Pre-existing liver cirrhosis presents unique challenges during the surgical management of such lesions. We carried out a retrospective study of 42 patients who had been managed surgically for skeletal metastases from hepatocellular carcinoma affecting the appendicular skeleton between January 2000 and December 2006. There were 38 men and four women with a mean age of 60.2 years (46 to 77). Surgery for a pathological fracture was undertaken in 30 patients and because of a high risk of fracture in 12. An intralesional surgical margin was achieved in 36 and a wide margin in six. Factors influencing survival were determined by univariate and multivariate analyses. The survival rates at one, two and three years after surgery were 42.2%, 25.8% and 19.8%, respectively. The median survival time was ten months (95% confidence interval 6.29 to 13.71). The number of skeletal metastases and the Child-Pugh grade were identified as independent prognostic factors by Cox regression analysis. The method of management of the hepatocellular carcinoma, its status in the liver, the surgical margin for skeletal metastases, the presence of a pathological fracture and adjuvant radiotherapy were not found to be significantly related to the survival of the patient, which was affected by hepatic function, as represented by the Child-Pugh grade.
We reviewed 87 patients who had undergone expansive cervical laminoplasty between 1999 and 2005. These were divided into two groups: those who had diabetes mellitus and those who did not. There were 31 patients in the diabetes group and 56 in the control group. Although a significant improvement in the Japanese Orthopaedic Association score was seen in both groups, the post-operative recovery rate in the control group was better than that of the diabetic group. The patients’ age and symptom duration adversely affected the rate of recovery in the diabetic group only. Smoking did not affect the outcome in either group. A logistic regression analysis found diabetes and signal changes in the spinal cord on MRI to be significant risk factors for a poor outcome (odds ratio 2.86, 3.02, respectively). Furthermore, the interaction of diabetes with smoking and/or age increased this risk. We conclude that diabetes mellitus, or the interaction of this with old age, can adversely affect outcome after cervical laminoplasty. However, smoking alone cannot be regarded as a risk factor.
Open surgery is rarely justified for the initial treatment of a unicameral bone cyst, but there is some debate concerning the relative effectiveness of closed methods. This study compared the results of steroid injection with those of autologous bone marrow grafting for the treatment of unicameral bone cysts. Between 1990 and 2001, 30 patients were treated by steroid injection and 28 by grafting with autologous bone marrow. The overall success rates were 86.7% and 92.0%, respectively (p >
0.05). The success rate after the initial procedure was 23.3% in the steroid group and 52.0% in those receiving autologous bone marrow (p <
0.05), and the respective cumulative success rates after second injections were 63.3% and 80.0% (p >
0.05). The mean number of procedures required was 2.19 (1 to 5) and 1.57 (1 to 3) (p <
0.05), the mean interval to healing was 12.5 months (4 to 32) and 14.3 months (7 to 36) (p >
0.05), and the rate of recurrence after the initial procedure was 41.7% and 13.3% in the steroid and in the autologous bone marrow groups, respectively (p <
0.05). Although the overall rates of success of both methods were similar, the steroid group had higher recurrence after a single procedure and required more injections to achieve healing.
In this retrospective study, we analysed the clinical features of neurilemoma when it is located in muscle. Twelve patients had an intramuscular neurilemoma as shown on magnetic resonance (MR) scans and confirmed at operation. In six it was located in the upper limb, in five in the lower limb, and in one in the back. The mean age of the patients was 41 years (12 to 58). Nine complained only of a palpable mass and the other three of a mass with slight tenderness. None had neurological symptoms or signs, such as radicular pain, a positive Tinel sign, or motor weakness. There were no postoperative complications or recurrence of the tumour after a mean follow-up of two years (1 to 10).
We have carried out prosthetic reconstruction in six patients with malignant or aggressively benign bone tumours of the distal tibia or fibula. The diagnoses were osteosarcoma in four patients, parosteal osteosarcoma in one and recurrent giant-cell tumour in one. Five tumours were in the distal tibia and one in the distal fibula. The mean duration of follow-up was 5.3 years (2.0 to 7.1). Reconstruction was achieved using custom-made, hinged prostheses which replaced the distal tibia and the ankle. The mean range of ankle movement after operation was 31° and the joints were stable. The average functional score according to the system of the International Society of Limb Salvage was 24.2 and five of the patients had a good outcome. Complications occurred in two with wound infection and talar collapse. All patients were free from neoplastic disease at the latest follow-up. Prosthetic reconstruction may be used for the treatment of malignant tumours of the distal tibia and fibula in selected patients.
We describe a three-year-old boy who had spontaneous regeneration of the entire lateral malleolus after injury, including the epiphysis, physis and metaphysis.
