Aims. This study aimed to use intraoperative free electromyography to examine how the placement of a retractor at different positions along the anterior acetabular wall may affect the femoral nerve during total hip arthroplasty (THA) when undertaken using the direct anterior approach (THA-DAA). Methods. Intraoperative free electromyography was performed during primary THA-DAA in 82 patients (94 hips). The highest position of the anterior acetabular wall was defined as the “12 o’clock” position (middle position) when the patient was in supine position. After exposure of the acetabulum, a retractor was sequentially placed at the ten, 11, 12, one, and two o’clock positions (right hip; from superior to inferior positions). Action potentials in the femoral nerve were monitored with each placement, and the incidence of positive reactions (defined as explosive, frequent, or continuous action potentials, indicating that the nerve was being compressed) were recorded as the primary outcome. Secondary outcomes included the incidence of positive reactions caused by removing the femoral head, and by placing a retractor during femoral exposure; and the incidence of femoral nerve palsy, as detected using manual testing of the strength of the quadriceps muscle. Results. Positive reactions were significantly less frequent when the retractor was placed at the ten (15/94; 16.0%), 11 (12/94; 12.8%), or 12 o’clock positions (19/94; 20.2%), than at the one (37/94; 39.4%) or two o’clock positions (39/94; 41.5%) (p < 0.050). Positive reactions also occurred when the femoral head was removed (28/94; 29.8%), and when a retractor was placed around the proximal femur (34/94; 36.2%) or
This study was designed to develop a model for predicting bone mineral density (BMD) loss of the femur after total hip arthroplasty (THA) using artificial intelligence (AI), and to identify factors that influence the prediction. Additionally, we virtually examined the efficacy of administration of bisphosphonate for cases with severe BMD loss based on the predictive model. The study included 538 joints that underwent primary THA. The patients were divided into groups using unsupervised time series clustering for five-year BMD loss of Gruen zone 7 postoperatively, and a machine-learning model to predict the BMD loss was developed. Additionally, the predictor for BMD loss was extracted using SHapley Additive exPlanations (SHAP). The patient-specific efficacy of bisphosphonate, which is the most important categorical predictor for BMD loss, was examined by calculating the change in predictive probability when hypothetically switching between the inclusion and exclusion of bisphosphonate.Aims
Methods
The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group). The study included 36 patients with T-HA stems and 30 with N-HA stems. Dual-energy X-ray absorptiometry was used to measure the change in periprosthetic BMD, one and two years postoperatively. The 3D contact between the stem and femoral cortical bone was evaluated using a density-mapping system, and clinical assessment, including patient-reported outcome measurements, was recorded.Aims
Methods
To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty. We retrospectively reviewed 639 subjects, aged 45 to 79 years, in the Osteoarthritis Initiative (OAI) study, who had symptomatic knees with Kellgren and Lawrence grade 2 to 4. Knees were categorized as neutral, valgus, and varus knees by measuring hip-knee-angles on hip-knee-ankle radiographs. Femorotibial JSW was measured on posteroanterior SF radiographs using a special software. The femorotibial compartment was divided into 16 subregions, and MR-tomographic measurements of cartilage volume, thickness, and subchondral bone area were documented. Linear regression with adjustment for age, sex, body mass index, and Kellgren and Lawrence grade was used.Aims
Methods
We wanted to evaluate the effects of a bone anabolic agent (bone morphogenetic protein 2 (BMP-2)) on an anti-catabolic background (systemic or local zoledronate) on fixation of allografted revision implants. An established allografted revision protocol was implemented bilaterally into the stifle joints of 24 canines. At revision surgery, each animal received one BMP-2 (5 µg) functionalized implant, and one raw implant. One group (12 animals) received bone graft impregnated with zoledronate (0.005 mg/ml) before impaction. The other group (12 animals) received untreated bone graft and systemic zoledronate (0.1 mg/kg) ten and 20 days after revision surgery. Animals were observed for an additional four weeks before euthanasia.Aims
Methods
The aims of this study were to investigate the ability to kneel after total knee arthroplasty (TKA) without patellar resurfacing, and its effect on patient-reported outcome measures (PROMs). Secondary aims included identifying which kneeling positions were most important to patients, and the influence of radiological parameters on the ability to kneel before and after TKA. This prospective longitudinal study involved 209 patients who underwent single radius cruciate-retaining TKA without patellar resurfacing. Preoperative EuroQol five-dimension questionnaire (EQ-5D), Oxford Knee Score (OKS), and the ability to achieve four kneeling positions were assessed including a single leg kneel, a double leg kneel, a high-flexion kneel, and a praying position. The severity of radiological osteoarthritis (OA) was graded and the pattern of OA was recorded intraoperatively. The flexion of the femoral component, posterior condylar offset, and anterior femoral offset were measured radiologically. At two to four years postoperatively, 151 patients with a mean age of 70.0 years (SD 9.44) were included. Their mean BMI was 30.4 kg/m2 (SD 5.36) and 60 were male (40%). They completed EQ-5D, OKS, and Kujala scores, assessments of the ability to kneel, and a visual analogue scale for anterior knee pain and satisfaction.Aims
Methods
Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity. A total of eight cadaveric lower limb pairs were arbitrarily assigned to either 1) isolated lateral plating, or 2) lateral and medial plating of the distal femur, with four specimens per group. Contralateral limbs served as matched controls. Pre- and post-contrast MRI was performed to quantify signal intensity enhancement in the distal femur. Further evaluation of intraosseous vascularity was done with barium sulphate infusion with CT scan imaging. Specimens were then injected with latex medium and dissection was completed to assess extraosseous vasculature.Aims
Methods
Although knee osteoarthritis (OA) is diagnosed and monitored radiologically, actual full-thickness cartilage loss (FTCL) has rarely been correlated with radiological classification. This study aims to analyze which classification system correlates best with FTCL and to assess their reliability. A prospective study of 300 consecutive patients undergoing unilateral total knee arthroplasty (TKA) for OA (mean age 69 years (44 to 91; standard deviation (SD) 9.5), 178 (59%) female). Two blinded examiners independently graded preoperative radiographs using five common systems: Kellgren-Lawrence (KL); International Knee Documentation Committee (IKDC); Fairbank; Brandt; and Ahlbäck. Interobserver agreement was assessed using the intraclass correlation coefficient (ICC). Intraoperatively, anterior cruciate ligament (ACL) status and the presence of FTCL in 16 regions of interest were recorded. Radiological classification and FTCL were correlated using the Spearman correlation coefficient.Aims
Methods
There is insufficient evidence to recommend the use of alternative polyethylene bearings in modular, fixed-bearing total knee arthroplasty (TKA). The purpose of this study was to compare standard polyethylene (SP) and highly crosslinked polyethylene (XLP) tibial liners in posterior-stabilized TKA, with osteolysis as the primary outcome and clinical results and the rate of re-operation as the secondary outcomes. This is a single-surgeon, prospective randomized study involving one design of modular posterior-stabilized TKA. An analysis of 122 TKAs with an SP compression moulded liner and 123 with an XLP liner was performed, with a mean follow-up of six years (2 to 11). Patients were evaluated clinically using the Knee Society score, Lower Extremity Activity Score (LEAS), and the presence of an effusion, and standard radiographs were assessed for radiolucent lines and osteolytic lesions.Aims
Patients and Methods
We report a study of the shapes of the tibial and femoral articular surfaces in sagittal, frontal and coronal planes which was performed on cadaver knees using two techniques, MRI and computer interpolation of sections of the articular surfaces acquired by a three-dimensional digitiser. The findings using MRI, confirmed in a previous study by dissection, were the same as those using the digitiser. Thus both methods appear to be valid anatomical tools. The tibial and femoral articular surfaces can be divided into anterior segments, contacting from 0° to 20 ± 10° of flexion, and posterior segments, contacting from 20 ± 10° to 120° of flexion. The medial and lateral compartments are asymmetrical, particularly anteriorly. Posteromedially, the femur is spherical and is located in a conforming, but partly deficient, tibial socket. Posterolaterally, it is circular only in the sagittal section and the tibia is flat centrally, sloping downwards both anteriorly and posteriorly to receive the meniscal horns. Anteromedially, the femur is convex with a sagittal radius larger than that posteriorly, while the tibia is flat sloping upwards and forwards. Anterolaterally, both the femoral and tibial surfaces are largely deficient. These shapes suggest that
Objectives. Our objective in this article is to test the hypothesis that
type 2 diabetes mellitus (T2DM) is a factor in the onset and progression
of osteoarthritis, and to characterise the quality of the articular
cartilage in an appropriate rat model. Methods. T2DM rats were obtained from the UC Davis group and compared
with control Lewis rats. The diabetic rats were sacrificed at ages
from six to 12 months, while control rats were sacrificed at six
months only. Osteoarthritis severity was determined via histology
in four knee quadrants using the OARSI scoring guide. Immunohistochemical
staining was also performed as a secondary form of osteoarthritic
analysis. Results. T2DM rats had higher mean osteoarthritis scores than the control
rats in each of the four areas that were analysed. However, only
the results at the medial and lateral
We have observed clinical cases where bone is formed in the overlaying muscle covering surgically created bone defects treated with a hydroxyapatite/calcium sulphate biomaterial. Our objective was to investigate the osteoinductive potential of the biomaterial and to determine if growth factors secreted from local bone cells induce osteoblastic differentiation of muscle cells. We seeded mouse skeletal muscle cells C2C12 on the hydroxyapatite/calcium sulphate biomaterial and the phenotype of the cells was analysed. To mimic surgical conditions with leakage of extra cellular matrix (ECM) proteins and growth factors, we cultured rat bone cells ROS 17/2.8 in a bioreactor and harvested the secreted proteins. The secretome was added to rat muscle cells L6. The phenotype of the muscle cells after treatment with the media was assessed using immunostaining and light microscopy.Objectives
Materials and Methods
Although it has been suggested that the outcome
after revision of a unicondylar knee replacement (UKR) to total knee
replacement (TKR) is better when the mechanism of failure is understood,
a comparative study on this subject has not been undertaken. A total of 30 patients (30 knees) who underwent revision of their
unsatisfactory UKR to TKR were included in the study: 15 patients
with unexplained pain comprised group A and 15 patients with a defined
cause for pain formed group B. The Oxford knee score (OKS), visual
analogue scale for pain (VAS) and patient satisfaction were assessed before
revision and at one year after revision, and compared between the
groups. The mean OKS improved from 19 (10 to 30) to 25 (11 to 41) in
group A and from 23 (11 to 45) to 38 (20 to 48) in group B. The
mean VAS improved from 7.7 (5 to 10) to 5.4 (1 to 8) in group A
and from 7.4 (2 to 9) to 1.7 (0 to 8) in group B. There was a statistically
significant difference between the mean improvements in each group
for both OKS (p = 0.022) and VAS (p = 0.002). Subgroup analysis
in group A, performed in order to define a patient factor that predicts
outcome of revision surgery in patients with unexplained pain, showed
no pre-operative differences between both subgroups. These results may be used to inform patients about what to expect
from revision surgery, highlighting that revision of UKR to TKR
for unexplained pain generally results in a less favourable outcome
than revision for a known cause of pain. Cite this article:
We prospectively followed 191 consecutive collarless
polished tapered (CPT) femoral stems, implanted in 175 patients
who had a mean age at operation of 64.5 years (21 to 85). At a mean
follow-up of 15.9 years (14 to 17.5), 86 patients (95 hips) were
still alive. The fate of all original stems is known. The 16-year
survivorship with re-operation for any reason was 80.7% (95% confidence
interval 72 to 89.4). There was no loss to follow-up, with clinical
data available on all 95 hips and radiological assessment performed
on 90 hips (95%). At latest follow-up, the mean Harris hip score
was 78 (28 to 100) and the mean Oxford hip score was 36 (15 to 48).
Stems subsided within the cement mantle, with a mean subsidence
of 2.1 mm (0.4 to 19.2). Among the original cohort, only one stem
(0.5%) has been revised due to aseptic loosening. In total seven
stems were revised for any cause, of which four revisions were required
for infection following revision of the acetabular component. A
total of 21 patients (11%) required some sort of revision procedure;
all except three of these resulted from failure of the acetabular
component. Cemented acetabular components had a significantly lower
revision burden (three hips, 2.7%) than Harris Galante uncemented
components (17 hips, 21.8%) (p <
0.001). The CPT stem continues to provide excellent radiological and
clinical outcomes at 15 years following implantation. Its results
are consistent with other polished tapered stem designs.
We describe the technique and results of medial
submuscular plating of the femur in paediatric patients and discuss its
indications and limitations. Specifically, the technique is used
as part of a plate-after-lengthening strategy, where the period
of external fixation is reduced and the plate introduced by avoiding
direct contact with the lateral entry wounds of the external fixator
pins. The technique emphasises that vastus medialis is interposed
between the plate and the vascular structures. A total of 16 patients (11 male and five female, mean age 9.6
years (5 to 17)), had medial submuscular plating of the femur. All
underwent distraction osteogenesis of the femur with a mean lengthening
of 4.99 cm (3.2 to 12) prior to plating. All patients achieved consolidation
of the regenerate without deformity. The mean follow-up was 10.5 months
(7 to 15) after plating for those with plates still Placing the plate on the medial side is advantageous when the
external fixator is present on the lateral side, and is biomechanically
optimal in the presence of a femoral defect. We conclude that medial
femoral submuscular plating is a useful technique for specific indications
and can be performed safely with a prior understanding of the regional
anatomy. Cite this article:
The clinical diagnosis of a partial tear of the
anterior cruciate ligament (ACL) is still subject to debate. Little
is known about the contribution of each ACL bundle during the Lachman
test. We investigated this using six fresh-frozen cadaveric lower
limbs. Screws were placed in the femora and tibiae as fixed landmarks
for digitisation of the bone positions. The femur was secured horizontally
in a clamp. A metal hook was screwed to the tibial tubercle and
used to apply a load of 150 N directed anteroposteriorly to the
tibia to simulate the Lachman test. The knees then received constant
axial compression and 3D knee kinematic data were collected by digitising
the screw head positions in 30° flexion under each test condition.
Measurements of tibial translation and rotation were made, first with
the ACL intact, then after sequential cutting of the ACL bundles,
and finally after complete division of the ACL. Two-way analysis
of variance analysis was performed. During the Lachman test, in all knees and in all test conditions,
lateral tibial translation exceeded that on the medial side. With
an intact ACL, both anterior and lateral tibial landmarks translated
significantly more than those on the medial side (p <
0.001).
With sequential division of the ACL bundles, selective cutting of
the posterolateral bundle (PLB) did not increase translation of
any landmark compared with when the ACL remained intact. Cutting the
anteromedial bundle (AMB) resulted in an increased anterior translation
of all landmarks. Compared to the intact ACL, when the ACL was fully
transected a significant increase in anterior translation of all
landmarks occurred (p <
0.001). However, anterior tibial translation
was almost identical after AMB or complete ACL division. We found that the AMB confers its most significant contribution
to tibial translation during the Lachman test, whereas the PLB has
a negligible effect on anterior translation. Section of the PLB
had a greater effect on increasing the internal rotation of the
tibia than the AMB. However, its contribution of a mean of 2.8°
amplitude remains low. The clinical relevance of our investigation
suggests that, based on anterior tibial translation only, one cannot distinguish
between a full ACL and an isolated AMB tear. Isolated PLB tears
cannot be detected solely by the Lachman test, as this bundle probably
contributes more resistance to the pivot shift.
We matched 78 patients with a loose cemented Charnley Elite Plus total hip replacement (THR) by age, gender, race, prosthesis and time from surgery with 49 patients with a well-fixed stable hip replacement, to determine if poor bone quality predisposes to loosening. Clinical, radiological, biomechanical and bone mineral density indicators of bone quality were assessed. Patients with loose replacements had more pain, were more likely to have presented with atrophic arthritis and to have a history of fragility fracture, narrower femoral cortices and lower peri-prosthetic or lumbar spine bone mineral density (all In this series of cemented hip replacements performed between 1994 and 1998, aseptic loosening was associated with poor bone quality. Patients with a THR should be screened for osteoporosis and have regular radiological surveillance.
