Modular un-cemented acetabular components are used in over 50% of UK hip replacements. Mal-seating of hard liners has been reported as a cause of failure which may be a result of errors in assembly, but also could be affected by deformation of the acetabular shell on insertion. Little information exists on in vivo shell deformation. Previous work has confirmed the importance of shell diameter and thickness upon shell behaviour, but mostly using single measurements in models or cold cadavers. Exploration of deformation and its relaxation over the first twenty minutes after implantation of eight generic metal cups at body temperature. Using a previously validated cadaveric model at controlled physiological temperature with standardised surgical technique, we tested the null hypothesis that there was no consistency for time dependent or directional change in deformation for a standard metal shell inserted under controlled conditions into the hip joint. Eight custom made titanium alloy (TiAl6V4) cups were implanted into 4 cadavers (8 hips). Time dependent cup deformation was determined using the previously validated ATOS Triple Scan III (ATOS) optical measurement system. The pattern of change in the shape of the surgically implanted cup was measured at 3 time points after insertion. We found consistency for quantitative and directional deformation of the shells. There was consistency for relaxation of the deformation with time. Immediate mean change in cup radius was 104μm (sd 32, range 67–153) relaxing to mean 96 μm (sd 32, range 63–150) after 10 minutes and mean 92 μm (sd 28, range 66–138) after 20 minutes. This work shows the time dependent deformation and relaxation of acetabular titanium shells and may aid determining the optimal time for insertion of the inner liner at surgery.
The objective of this study was to assess the biomechanical stability of three types of chondral flap repair and a hydrogel scaffold implantation on the acetabular articular surface using a physiological human cadaveric model. Chondral flaps were created in the antero-superior zone of the acetabulum in a series of human cadaveric hip joints. The chondral flap was repaired by fibrin glue, cyanoacrylate, suture technique and an agarose hydrogel scaffold sealed with fibrin glue using 6 hips in each case. After each repair, the specimens were mounted in a validated jig and tested for 1500 gait cycles. In order to determine the stability of the repair, specimens were evaluated arthroscopically at specific intervals.Objective
Methods
Background. Instability is one of the most common complications after total hip arthroplasty (THA), particularly when using the posterior approach. Repair of the posterior capsule has proven to significantly decrease the incidence of posterior hip dislocation. The purpose of the present study is to evaluate if braided polyblend suture provides a stronger repair of the posterior soft tissues when compared to a non-absorbable suture repair after a posterior approach to the hip. Methods. Ten cadaveric hips from donors who were a mean (and standard deviation) of 80 ± 9 years old at the time of death were evaluated after posterior soft tissue repair utilizing two different techniques. Five specimens were repaired using no. 2 non-absorbable sutures while five specimens had a repair utilizing braided polyblend suture with a rucking hitch knot technique.
Hip resurfacing remains a safe and effective option according to registry data. Results in women were less reliable, in part owing to soft tissue impingement. Biolox Delta ceramic bearing couples are now in widespread use with very low complication rates. We set about merging these three elements to develop a novel hip resurfacing arthroplasty. Contours of both acetabular and femoral components were generated from biometric data, adapted to the constraints of ceramic machining, to ensure that radii blended from the bearing surface avoiding any sharp boundaries. Plasma spray coating with titanium and hydroxyapatite direct onto ceramic was developed and tested using shear, tensile and taber abrasion testing. Wear testing was carried out to 5 million cycles according to the ASTM. Destructive testing was carried out in a variety of test conditions and angles.
This study uses prospective registry data to compare early patient outcomes following arthroscopic repair or debridement of the acetabular labrum. Data on adult patients who underwent arthroscopic labral debridement or repair between 1 January 2012 and 31 July 2019 were extracted from the UK Non-Arthroplasty Hip Registry. Patients who underwent microfracture, osteophyte excision, or a concurrent extra-articular procedure were excluded. The EuroQol five-dimension (EQ-5D) and International Hip Outcome Tool 12 (iHOT-12) questionnaires were collected preoperatively and at six and 12 months post-operatively. Due to concerns over differential questionnaire non-response between the two groups, a combination of random sampling, propensity score matching, and pooled multivariable linear regression models were employed to compare iHOT-12 improvement.Aims
Methods
Arthroplasty skills need to be acquired safely during training, yet operative experience is increasingly hard to acquire by trainees. Virtual reality (VR) training using headsets and motion-tracked controllers can simulate complex open procedures in a fully immersive operating theatre. The present study aimed to determine if trainees trained using VR perform better than those using conventional preparation for performing total hip arthroplasty (THA). A total of 24 surgical trainees (seven female, 17 male; mean age 29 years (28 to 31)) volunteered to participate in this observer-blinded 1:1 randomized controlled trial. They had no prior experience of anterior approach THA. Of these 24 trainees, 12 completed a six-week VR training programme in a simulation laboratory, while the other 12 received only conventional preparatory materials for learning THA. All trainees then performed a cadaveric THA, assessed independently by two hip surgeons. The primary outcome was technical and non-technical surgical performance measured by a THA-specific procedure-based assessment (PBA). Secondary outcomes were step completion measured by a task-specific checklist, error in acetabular component orientation, and procedure duration.Aims
Patients and Methods
Fractures of the proximal femur are a common clinical problem, and a number of orthopaedic devices are available for the treatment of such fractures. The objective of this study was to assess the rotational stability, a common failure predictor, of three different rotational control design philosophies: a screw, a helical blade and a deployable crucifix. Devices were compared in terms of the mechanical work (W) required to rotate the implant by 6° in a bone substitute material. The substitute material used was Sawbones polyurethane foam of three different densities (0.08 g/cm3, 0.16 g/cm3 and 0.24 g/cm3). Each torsion test comprised a steady ramp of 1°/minute up to an angular displacement of 10°.Objectives
Methods
Recently, there has been considerable interest in quantifying
the associations between bony abnormalities around and in the hip
joint and osteoarthritis (OA). Our aim was to investigate the relationships
between acetabular undercoverage, acetabular overcoverage, and femoroacetabular
impingement (FAI) with OA of the hip, which currently remain controversial. A total of 545 cadaveric skeletons (1090 hips) from the Hamann-Todd
osteological collection were obtained. Femoral head volume (FHV),
acetabular volume (AV), the FHV/AV ratio, acetabular version, alpha
angle and anterior femoral neck offset (AFNO) were measured. A validated
grading system was used to quantify OA of the hip as minimal, moderate,
or severe. Multiple linear and multinomial logistic regression were
used to determine the factors that correlated independently with
the FHV, AV, and the FHV/AV ratio. Aims
Materials and Methods
We aimed to quantify the relative contributions of the medial
femoral circumflex artery (MFCA) and lateral femoral circumflex
artery (LFCA) to the arterial supply of the head and neck of the
femur. We acquired ten cadaveric pelvises. In each of these, one hip
was randomly assigned as experimental and the other as a matched
control. The MFCA and LFCA were cannulated bilaterally. The hips
were designated LFCA-experimental or MFCA-experimental and underwent
quantitative MRI using a 2 mm slice thickness before and after injection
of MRI-contrast diluted 3:1 with saline (15 ml Gd-DTPA) into either
the LFCA or MFCA. The contralateral control hips had 15 ml of contrast
solution injected into the root of each artery. Next, the MFCA and
LFCA were injected with a mixture of polyurethane and barium sulfate
(33%) and their extra-and intra-arterial course identified by CT
imaging and dissection.Aims
Materials and Methods
The acetabular labrum is a soft-tissue structure
which lines the acetabular rim of the hip joint. Its role in hip
joint biomechanics and joint health has been of particular interest
over the past decade. In normal hip joint biomechanics, the labrum
is crucial in retaining a layer of pressurised intra-articular fluid
for joint lubrication and load support/distribution. Its seal around
the femoral head is further regarded as a contributing to hip stability through
its suction effect. The labrum itself is also important in increasing
contact area thereby reducing contact stress. Given the labrum’s
role in normal hip joint biomechanics, surgical techniques for managing
labral damage are continuously evolving as our understanding of
its anatomy and function continue to progress. The current paper
aims to review the anatomy and biomechanical function of the labrum
and how they are affected by differing surgical techniques. Take home message: The acetabular labrum plays a critical role
in hip function and maintaining and restoring its function during
surgical intervention remain an essential goal. Cite this article:
We investigated the detailed anatomy of the gluteus
maximus, gluteus medius and gluteus minimus and their neurovascular
supply in 22 hips in 11 embalmed adult Caucasian human cadavers.
This led to the development of a surgical technique for an extended
posterior approach to the hip and pelvis that exposes the supra-acetabular
ilium and preserves the glutei during revision hip surgery. Proximal
to distal mobilisation of the gluteus medius from the posterior
gluteal line permits exposure and mobilisation of the superior gluteal
neurovascular bundle between the sciatic notch and the entrance
to the gluteus medius, enabling a wider exposure of the supra-acetabular
ilium. This technique was subsequently used in nine patients undergoing
revision total hip replacement involving the reconstruction of nine
Paprosky 3B acetabular defects, five of which had pelvic discontinuity.
Intra-operative electromyography showed that the innervation of
the gluteal muscles was not affected by surgery. Clinical follow-up
demonstrated good hip abduction function in all patients. These
results were compared with those of a matched cohort treated through
a Kocher–Langenbeck approach. Our modified approach maximises the
exposure of the ilium above the sciatic notch while protecting the
gluteal muscles and their neurovascular bundle. Cite this article: Bone Joint J 2014;96-B:48–53.
