We report the kinematic and early clinical results
of a patient- and observer-blinded randomised controlled trial in which
CT scans were used to compare potential impingement-free range of
movement (ROM) and acetabular component cover between patients treated
with either the navigated ‘femur-first’ total hip arthroplasty (THA) method
(n = 66; male/female 29/37, mean age 62.5 years; 50 to 74) or conventional
THA (n = 69; male/female 35/34, mean age 62.9 years; 50 to 75).
The Hip Osteoarthritis Outcome Score, the Harris hip score, the
Euro-Qol-5D and the Mancuso THA patient expectations score were
assessed at six weeks, six months and one year after surgery. A
total of 48 of the patients (84%) in the navigated ‘femur-first’
group and 43 (65%) in the conventional group reached all the desirable
potential ROM boundaries without prosthetic impingement for activities
of daily living (ADL) in flexion, extension, abduction, adduction
and rotation (p = 0.016). Acetabular component cover and surface
contact with the host bone were >
87% in both groups. There was
a significant difference between the navigated and the conventional
groups’ Harris hip scores six weeks after surgery (p = 0.010). There
were no significant differences with respect to any clinical outcome
at six months and one year of follow-up. The navigated ‘femur-first’
technique improves the potential ROM for ADL without prosthetic
impingement, although there was no observed clinical difference
between the two treatment groups. Cite this article:
To confirm whether developmental dysplasia of
the hip has a risk of hip impingement, we analysed maximum ranges
of movement to the point of bony impingement, and impingement location
using three-dimensional (3D) surface models of the pelvis and femur
in combination with 3D morphology of the hip joint using computer-assisted methods.
Results of computed tomography were examined for 52 hip joints with
DDH and 73 normal healthy hip joints. DDH shows larger maximum extension
(p = 0.001) and internal rotation at 90° flexion (p <
0.001).
Similar maximum flexion (p = 0.835) and external rotation (p = 0.713)
were observed between groups, while high rates of extra-articular
impingement were noticed in these directions in DDH (p <
0.001).
Smaller cranial acetabular anteversion (p = 0.048), centre-edge
angles (p <
0.001), a circumferentially shallower acetabulum,
larger femoral neck anteversion (p <
0.001), and larger alpha
angle were identified in DDH. Risk of anterior impingement in retroverted
DDH hips is similar to that in retroverted normal hips in excessive
adduction but minimal in less adduction. These findings might be
borne in mind when considering the possibility of extra-articular
posterior impingement in DDH being a source of pain, particularly
for patients with a highly anteverted femoral neck. Cite this article:
Aims. Natural Language Processing (NLP) offers an automated method to extract data from unstructured free text fields for arthroplasty registry participation. Our objective was to investigate how accurately NLP can be used to extract structured clinical data from unstructured clinical notes when compared with manual data extraction. Methods. A group of 1,000 randomly selected clinical and hospital notes from eight different surgeons were collected for patients undergoing primary arthroplasty between 2012 and 2018. In all, 19 preoperative, 17 operative, and two postoperative variables of interest were manually extracted from these notes. A NLP algorithm was created to automatically extract these variables from a training sample of these notes, and the algorithm was tested on a random test sample of notes. Performance of the NLP algorithm was measured in Statistical Analysis System (SAS) by calculating the accuracy of the variables collected, the ability of the algorithm to collect the correct information when it was indeed in the note (sensitivity), and the ability of the algorithm to not collect a certain data element when it was not in the note (specificity). Results. The NLP algorithm performed well at extracting variables from unstructured data in our random test dataset (accuracy = 96.3%, sensitivity = 95.2%, and specificity = 97.4%). It performed better at extracting data that were in a structured, templated format such as
Aims. The hip’s capsular ligaments passively restrain extreme
A total of 31 patients, (20 women, 11 men; mean
age 62.5 years old; 23 to 81), who underwent conversion of a Girdlestone
resection-arthroplasty (RA) to a total hip replacement (THR) were
compared with 93 patients, (60 women, 33 men; mean age 63.4 years
old; 20 to 89), who had revision THR surgery for aseptic loosening
in a retrospective matched case-control study. Age, gender and the
extent of the pre-operative bone defect were similar in all patients.
Mean follow-up was 9.3 years (5 to 18). Pre-operative function and
Orientation of the native acetabular plane as defined by the transverse acetabular ligament (TAL) and the posterior labrum was measured intra-operatively using computer-assisted navigation in 39 hips. In order to assess the influence of alignment on impingement, the
Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the
Dual mobility cups have two points of articulation,
one between the shell and the polyethylene (external bearing) and
one between the polyethylene and the femoral head (internal bearing).
Movement occurs at the inner bearing; the outer bearing only moves
at extremes of movement. Dislocation after total hip arthroplasty (THA) is a cause of
much morbidity and its treatment has significant cost implications.
Dual mobility cups provide an increased
In this in vitro study of the
hip joint we examined which soft tissues act as primary and secondary
passive rotational restraints when the hip joint is functionally
loaded. A total of nine cadaveric left hips were mounted in a testing
rig that allowed the application of forces, torques and rotations
in all six degrees of freedom. The hip was rotated throughout a
complete
Orientation of the acetabular component influences
wear,
Dislocation remains among the most common complications
of, and reasons for, revision of both primary and revision total
hip replacements (THR). Hence, there is great interest in maximising
stability to prevent this complication. Head size has been recognised
to have a strong influence on the risk of dislocation post-operatively.
As femoral head size increases, stability is augmented, secondary
to an increase in impingement-free
The β-angle is a radiological tool for measuring the distance between the pathological head-neck junction and the acetabular rim with the hip in 90° of flexion in patients with femoroacetabular impingement. Initially it was measured using an open-chamber MRI. We have developed a technique to measure this angle on plain radiographs. Correlation analysis was undertaken to determine the relationship between the
We compared a modular neck system with a non-modular system in a cementless anatomical total hip replacement (THR). Each group consisted of 74 hips with developmental hip dysplasia. Both groups had the same cementless acetabular component and the same articulation, which consisted of a conventional polyethylene liner and a 28 mm alumina head. The mean follow-up was 14.5 years (13 to 15), at which point there were significant differences in the mean total Harris hip score (modular/non-modular: 98.6 (64 to 100)/93.8 (68 to 100)), the mean range of abduction (32° (15° to 40°)/28 (0° to 40°)), use of a 10° elevated liner (31%/100%), the incidence of osteolysis (27%/79.7%) and the incidence of equal leg lengths (≥ 6 mm, 92%/61%). There was no disassociation or fracture of the modular neck. The modular system reduces the need for an elevated liner, thereby reducing the incidence of osteolysis. It gives a better
In this prospective study a total of 80 consecutive
Chinese patients with Crowe type I or II developmental dysplasia of
the hip were randomly assigned for hip resurfacing arthroplasty
(HRA) or total hip replacement (THR). Three patients assigned to HRA were converted to THR, and three
HRA patients and two THR patients were lost to follow-up. This left
a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips)
who underwent THR. The mean follow-up was 59.4 months (52 to 70)
in the HRA group and 60.6 months (50 to 72) in the THR group. There was
no failure of the prosthesis in either group. Flexion of the hip
was significantly better after HRA, but there was no difference
in the mean post-operative Harris hip scores between the groups.
The mean size of the acetabular component in the HRA group was significantly
larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was
no difference in the mean abduction angle of the acetabular component
between the two groups. Although the patients in this series had risk factors for failure
after HRA, such as low body weight, small femoral heads and dysplasia,
the clinical results of resurfacing in those with Crowe type I or
II hip dysplasia were satisfactory. Patients in the HRA group had
a better
The outcome of total hip replacement (THR) is potentially affected by the body mass index (BMI) of the patient. We studied the outcome of 2026 consecutive primary cementless THRs performed for osteoarthritis. The mean follow-up was 6.3 years (0 to 11.71) and no patient was lost to follow-up for survival analysis. The patients were divided into two groups according to their BMI as follows: non-obese (BMI <
30 kg/m. 2. ) and obese (BMI ≥ 30 kg/m. 2. ). The obese patient undergoing surgery was found to be significantly younger (p <
0.001). The log-rank test for equality of survival showed no difference in the mid-term survival (p = 0.552) with an estimated survival at 11 years of 95.2% (95% CI 92.5 to 98.0) in the non-obese and 96.7% (95% CI 94.9 to 98.5) in the obese groups. The clinical and radiological outcome was determined in a case-matched study performed on 134 obese individuals closely matched with 134 non-obese controls. The non-obese group was found to have a significantly higher post-operative Harris hip score (p <
0.001) and an increased
We reviewed the long-term results at ten to 12 years of 118 total hip replacements in 109 patients using a second-generation hemispherical cementless acetabular component (Reflection) designed to address the problem of backside wear. Five patients (five hips) died and six patients (seven hips) were lost to follow-up. The remaining 98 patients (106 hips) had a mean age of 62.9 years (34.0 to 86.2) A rate of revision for aseptic loosening of 0.9%, and predictable results were found with respect to radiological evidence of fixation, lack of pain, walking ability,
Pelvic tilt (PT) can significantly change the functional orientation of the acetabular component and may differ markedly between patients undergoing total hip arthroplasty (THA). Patients with stiff spines who have little change in PT are considered at high risk for instability following THA. Femoral component position also contributes to the limits of impingement-free range of motion (ROM), but has been less studied. Little is known about the impact of combined anteversion on risk of impingement with changing pelvic position. We used a virtual hip ROM (vROM) tool to investigate whether there is an ideal functional combined anteversion for reduced risk of hip impingement. We collected PT information from functional lateral radiographs (standing and sitting) and a supine CT scan, which was then input into the vROM tool. We developed a novel vROM scoring system, considering both seated flexion and standing extension manoeuvres, to quantify whether hips had limited ROM and then correlated the vROM score to component position.Aims
Methods
We evaluated all cases involving the combined use of a subtrochanteric derotational femoral shortening osteotomy with a cemented Exeter stem performed at our institution. With severe developmental dysplasia of the hip an osteotomy is often necessary to achieve shortening and derotation of the proximal femur. Reduction can be maintained with a 3.5 mm compression plate while the implant is cemented into place. Such a plate was used to stabilise the osteotomy in all cases. Intramedullary autograft helps to prevent cement interposition at the osteotomy site and promotes healing. There were 15 female patients (18 hips) with a mean age of 51 years (33 to 75) who had a Crowe IV dysplasia of the hip and were followed up for a mean of 114 months (52 to 168). None was lost to follow-up. All clinical scores were collected prospectively. The Charnley modification of the Merle D’Aubigné-Postel scores for pain, function and
We carried out primary cemented total hip arthroplasty (THA) on 25 hips in 21 patients with developmental dysplasia of the hip, using autogenous acetabular bone grafts. The socket was placed at the level of the true acetabulum and bone from the femoral neck was used as graft. Five hips were excluded, leaving 20 which were followed up for a mean of 12.9 years (10 to 18). The mean modified Merle d’Aubigné and Postel functional scores were 5.6 for pain, 4.3 for mobility and 4.2 for
We reviewed 261 patients with 320 Charnley low-friction arthroplasties who had a mean follow-up of 22 years 10 months (20 to 30). Of these, 93.9% considered the operation to be a success; 82.3% were free from pain and 11.6% had occasional discomfort. Satisfactory function was achieved in 59.6% and 62% had an excellent