Research on hip biomechanics has analyzed femoroacetabular contact pressures and forces in distinct hip conditions, with different procedures, and used diverse loading and testing conditions. The aim of this scoping review was to identify and summarize the available evidence in the literature for hip contact pressures and force in cadaver and in vivo studies, and how joint loading, labral status, and femoral and acetabular morphology can affect these biomechanical parameters. We used the PRISMA extension for scoping reviews for this literature search in three databases. After screening, 16 studies were included for the final analysis.Aims
Methods
Removal of bullets retained within joints is indicated to prevent mechanical blockade, 3rd body wear and resultant arthritis, plus lead arthropathy and systemic lead poisoning. The literature is sparse on this subject, with mostly sporadic case reports utilizing hip arthroscopy. We report on the largest series of removal of bullets from the
Aims. Developmental dysplasia of the hip (DDH) is a complex musculoskeletal disease that occurs mostly in children. This study aimed to investigate the molecular changes in the
Abstract. OBJECTIVES. Abnormal joint mechanics have been proposed as adversely affecting natural
Aims. Surgical approaches that claim to be minimally invasive, such as the direct anterior approach (DAA), are reported to have a clinical advantage, but are technically challenging and may create more injury to the soft-tissues during joint exposure. Our aim was to quantify the effect of soft-tissue releases on the joint torque and femoral mobility during joint exposure for hip resurfacing performed via the DAA. Methods. Nine fresh-frozen
Aims. Osteoporosis is common in total hip arthroplasty (THA) patients. It plays a substantial factor in the surgery’s outcome, and previous studies have revealed that pharmacological treatment for osteoporosis influences implant survival rate. The purpose of this study was to examine the prevalence of and treatment rates for osteoporosis prior to THA, and to explore differences in osteoporosis-related biomarkers between patients treated and untreated for osteoporosis. Methods. This single-centre retrospective study included 398
The interleukin-6/gp130-associated Janus Kinases/STAT3 axis is known to play an important role in mediating inflammatory signals, resulting in production of matrix metalloproteinase-3 (MMP-3). The
Despite improvements in techniques and materials, aseptic loosening of artificial
Aims. Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with acetabular component positioning. Methods. 3D CT imaging was combined with a recently validated method of mapping bearing surface wear in retrieved hip implants. The asymmetrical stabilizing fins of Birmingham hip replacements (BHRs) allowed the co-registration of their acetabular wear maps and their computational models, segmented from CT scans. The in vivo location of edge-wear was measured within a standardized coordinate system, defined using the anterior pelvic plane. Results. Edge-wear was found predominantly along the superior acetabular edge in all cases, while its median location was 8° (interquartile range (IQR) -59° to 25°) within the anterosuperior quadrant. The deepest point of these scars had a median location of 16° (IQR -58° to 26°), which was statistically comparable to their centres (p = 0.496). Edge-wear was in closer proximity to the superior apex of the cups with greater angles of acetabular inclination, while a greater degree of anteversion influenced a more anteriorly centred scar. Conclusion. The anterosuperior location of edge-wear was comparable to the degradation patterns observed in acetabular cartilage, supporting previous findings that
Abstract. Objectives. Hip joint laxity after total hip arthroplasty (THA) has been considered to cause microseparation and lead to complications, including wear and dislocation. In the native hip, the hip capsular ligaments may tighten at the limits of range of hip motion and provide a passive stabilising force preventing edge loading and reduce the risk of dislocation. Previous attempts to characterise mechanical properties of hip capsular ligaments have been largely variable and there are no cadaveric studies quantifying the force contributions of each ligament in different hip positions. In this study we quantify the passive force contribution of the hip capsular ligaments throughout a complete range of motion (ROM). Methods. Nine human cadaveric hip specimens (6 males and 3 females) with mean age of (76.4 ± 9.0 years) were skeletonised, preserving the capsular ligaments. Prepared specimens were tested in a 6 degree of freedom system to assess ROM with 5 Nm torque applied in external and internal rotation throughout hip flexion and extension. Capsular ligaments were resected in a stepwise fashion to assess internal force contributions of the iliofemoral (superior and inferior), pubofemoral, and ischiofemoral ligaments during ROM. Results. In external rotation, the superior and inferior iliofemoral ligament minimum force contributions were (136.52 ± 27.15 N) in flexion and (82.40 ± 27.85 N) in extension, respectively. In internal rotation, the ischiofemoral ligament force contributions were dominant in adducted-flexion positions and abducted-extension positions. Conclusions. These findings provide insights into the primary capsular structures that stabilise the
Objectives. To validate the precision of digitally reconstructed radiograph (DRR) radiostereometric analysis (RSA) and the model-based method (MBM) RSA with respect to benchmark marker-based (MM) RSA for evaluation of kinematics in the native
Hip osteoarthritis (OA) is a disorder of high socio-economic relevance. The causes of hip osteoarthritis are multifactorial; however, the epidemiological literature regularly cites occupational tasks, such as heavy lifting and carrying, as a risk factor for the development of hip OA. The level of mechanical stresses upon the
Introduction. Soft tissue artefact (STA) affects the kinematics retrieved with skin marker-based motion capture, and thus influences the outcomes of biomechanical models that rely on such kinematics. To date, compensation for STA remains an unsolved challenge due to its complexity. Factors include its dependency on subject, on motion activity and on skin-marker configuration, its non-linearity over the movement cycle, and the scarcity of reference in-vivo estimations. The objective of this study was extending the existing knowledge of the effects of STA on the kinematics of the
Objectives. The high revision rates of the DePuy Articular Surface Replacement (ASR) and the DePuy ASR XL (the total hip arthroplasty (THA) version) have led to questions over the viability of metal-on-metal (MoM)
Background. In vivo fluoroscopic studies have proven that femoral head sliding and separation from within the acetabular cup during gait frequently occur for subjects implanted with a total hip arthroplasty. It is hypothesized that these atypical kinematic patterns are due to component malalignments that yield uncharacteristically higher forces on the
Introduction. Native
INTRODUCTION. The purpose of this study is to elucidate longitudinal kinematic changes of the
Studies of infant hip development to date have been limited by considering only the changes in appearance of a single ultrasound slice (Graf’s standard plane). We used 3D ultrasound (3DUS) to establish maturation curves of normal infant hip development, quantifying variation by age, sex, side, and anteroposterior location in the hip. We analyzed 3DUS scans of 519 infants (mean age 64 days (6 to 111 days)) presenting at a tertiary children’s hospital for suspicion of developmental dysplasia of the hip (DDH). Hips that did not require ultrasound follow-up or treatment were classified as ‘typically developing’. We calculated traditional DDH indices like α angle (αSP), femoral head coverage (FHCSP), and several novel indices from 3DUS like the acetabular contact angle (ACA) and osculating circle radius (OCR) using custom software.Aims
Methods
Introduction. Advantages of ceramic materials for
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
Pre-operative definitive diagnosis of infection in painful total hip arthroplasty (THA) is not always easy to be established, making the intra-operative decision-making process crucial in management of revision hip surgery. Calprotectin is a promising point-of-care novel biomarker that has displayed high accuracy in detecting PJIs. From November 2020 to December 2022, 105 patients with painful primary THA were treated with revision THA in 3 orthopaedic departments. Pre-operatively, 23 were considered infected and treated with two-stage revision THA. The remaining 82 were likely infected according to the 2019 EBJIS criteria. The suspicion of low-grade infection was based on clinical (rest and/or night pain), laboratory (CRP, ESR, WBC – normal or slightly elevated) and radiological evaluation (loosening). Hip aspiration under CT imaging was performed in these cases and 34 of them yielded positive culture and were treated with two-stage revision. Aspiration was ineffective in the remaining 48 cases (33 negative, 15 unsuccessful attempts). Intra-operatively, calprotectin was measured with lateral flow immunoassay test in these patients. Cases with calprotectin levels ≥ 50 mg/L were treated with 2-stage revision THA; otherwise, they were considered not-infected and one-stage revision was performed. Synovial fluid and tissue samples were collected for analysis. Implants were sent for sonication fluid cultures. Calprotectin was positive (≥ 50 mg/L) in 27 cases and negative in 21 cases. There was 1 false negative case with positive tissue cultures. Out of the 27 positive cases, 25 had positive tissue cultures and sonication. However, 2 cases with high calprotectin levels (>200 mg/L) were not infected. The false positive result was attributed to severe metallosis. Calprotectin sensitivity was 96.2%, specificity 90.9%, PPV 92.6%, NPV 95.2%, AUC 0.935. The results of this ongoing study indicate that calprotectin seems to be a valuable tool in facilitating the intra-operative decision-making process in cases that low-grade infection is suspected and diagnosis cannot be established pre-operatively.
We have utilized arthroscopic arthroplasty of the
Introduction: Septic arthritis of the
1. One hundred patients with dislocation of the
Aims. Our aim in this study was to describe the long-term survival
of the native
1. This is a simple clinical study of the end-results of arthrodesis of the
Introduction. A deep squat (DS) is a challenging motion at the level of the
Background and Aims: Concentric pressure of the femoral head on acetabulum is the necessary prerequisite for normal hip development. In the case of diminished
Introduction and aims: Increasingly the accurate reconstruction of the hip in total hip arthroplasty is planned using pre-operative pelvic radiographs. The accuracy of reconstruction is assessed using post-operative pelvic radiographs. This study defines significant variations in the offset,
Surgical dislocation of the
Similar to the radiological findings in rapidly destructive arthrosis of the
The location of the
Developmental dysplasia of the hip (DDH) is the most common post-natal skeletal abnormality. It is widely acknowledged that conditions which cause or result in reduced movement in utero are contributing factors to the incidence of DDH. However, the hypothesis that prenatal movement plays a role in normal development of the
Introduction. Nociceptive and neuropathic components both contribute to chronic pain. Since these components require different pain management strategies, correct pain diagnosis before and during treatment is important. Freynhagen et al. (2006) reported that they had developed and validated the pain-DETECT questionnaire (PD-Q) to detect neuropathic components in chronic low back pain patients. They also reported that 37% of unselected cohort of chronic LBP patients had predominantly neuropathic pain. However, the extent to which neuropathic components relate to the pathomechanism of pain deriving from osteoarthritis of
In this study we used subject-specific finite
element analysis to investigate the mechanical effects of rotational acetabular
osteotomy (RAO) on the
Impact relief ability of Metal-on-Metal artificial
The pressure distribution between the cartilaginous surfaces in the human
With the growing number of individuals with asymptomatic cam-type deformities, elevated alpha angles alone do not always explain clinical signs of femoroacetabular impingement (FAI). Differences in additional anatomical parameters may affect
Introduction The consequence of discongrency of the
1. In this series of 150 cases of arthritis of the
1. Three cases of osteochondromatosis of the
1. The operation of pseudarthrosis of the
Introduction. A deep squat (DS) is a challenging motion at the level of the
Surgical invention to preserve the native
Aims: The present experiment addressed the question whether lipopolysaccharides (LPS),
Purpose: The purpose of our study is to estimate the effectiveness of Parecoxib in the post surgical analgesia in the fractures of the
Introduction: The aim of the present study was to evaluate the efficacy of the vacuum–assisted closure (V.A.C.) therapy in the treatment of early
Introduction. In vitro studies have shown that low clearance metal-on-metal
Over the past years there has been considerable interest, debate and controversy over the role of surgical approaches for total hip replacements. The leading role belongs to appropriate direction and anatomical structures mobilization during surgical approach. We strictly follow the paradigm that surgical approach must enable gentle handling vessels, nerves, muscles and fascias structures create good viewing of target field with possibilities of free manipulations, give opportunity for widening at any level. This experimental study was performed to quantitatively comparesomethemostcommonlyusedsurgicalapproaches to
Introduction: Previous in vivo kinematic analyses of the
Aim: Is there a need of reduction control with MRI after closed reduction of unstable hips in children with CDH ? Methods: So far 88 children with unstable hip joints received a hip plaster of paris after closed reduction. The x-ray examination of the hip was followed by an MRI of the presumed reduced hip. The MRI examination was performed under sedation of the children with choralhydrat. Results: Out of the 88
Artificial joints have been increasingly used in the treatment of physically disabled people who suffer from joint diseases such as osteoarthritis and rheumatoid arthritis. Ultra high molecular weight polyethylene (UHMWPE) is commonly used in hard-on-polymer joints as an impact-absorbing material for artificial
Introduction. Melorheostosis is a rare bone dysplasia characterized by its classic radiographic appearance resembling dripping candle wax. The condition was originally described by Leri and Joanny in 1922. Its etiology is not fully known and treatment in most instances has been symptomatic. There are nearly 350 reported cases on melorheostosis, joint replacement has been successfully attempted in the shoulder and knee joint. We describe a case of severe melorheostosis affecting the left hip causing secondary osteo-arthritis, which was treated with a total hip replacement (THR). To the best of our knowledge this is the first reported case of its kind in the World literature. Case history. A 52-year-old male of Indian origin with known melorheostosis of the left leg for over 30 years, presented with symptoms suggestive of severe osteo-arthritis of the left hip. Previously he had been treated for melorheostosis of the knee joint (fig 1a & 1b) with excisions and decompression of the medial femoral condyle. His left hip became more painful over the last few years. He had a fixed flexion deformity of 20° of the hip, severe muscle wasting and the affected leg was 3 cm longer than the right leg. Radiographs (fig 2a & 2b) confirmed the presence of sclerotic new bone in the acetabulum eroding the femoral head. He had the classical dripping candle wax appearance along the medial border of the neck and shaft of the femur. He underwent a THR using a Corail-Pinnacle un-cemented prosthesis using ceramic on polyethylene bearing surfaces (fig 3a & 3b). Post operatively he made a quick recovery and there was a marked improvement in his symptoms and functional outcome scores at 6 weeks. Discussion. Melorheostosis has an incidence of 0.9 in one million and affects men and women equally. It can affect any site in the body, however lower limbs are more commonly affected. It classically presents on only one side of the cortex of long bones. It is common in synovial joints and crosses the joint line in 35% cases. Its etiology is unknown and it is a benign condition but there are 3 reported cases in literature associated with malignancy. Chronic pain and deformity from melorheostosis can be severely debilitating for patients. Its management in most cases is conservative. Surgical intervention is advocated in chronic debilitating symptoms. Successful resection of these lesions can translate into near complete resolution of the symptoms. A Total hip replacement can be used to treat severe melorheostosis of the
Purpose and Background. Leg length discrepancy (LLD) occurs commonly and has been associated with osteoarthritis of the knee and the
Introduction. Periprosthetic osteolysis is considered the main problem limiting the longevity and clinical success of artificial
1. Fifty cases of arthrodesis of the
Complete debridement for synovial chondromatosis of the
Purpose of the study: Transadductor approaches to the
Introduction. Translational surgical mismatch in the centres of rotation of the femoral head and acetabular cup in hip joint replacements can lead to dynamic microseparation resulting in edge loading contact [1]. Increased wear in retrieved ceramic-on-ceramic bearings has been associated with edge loading [2].
Photoelastic techniques were used to study the stresses in models which represented the central frontal plane of a normal
1. A specially designed loading apparatus and dyeing technique have been used to demonstrate the weight-bearing areas in fifty-one normal adult
Introduction. Metal-on-polyethylene (MoP) is the most commonly used bearing couple in total hip replacements (THRs). Retrieval studies (Cooper et al, 2012, JBJS, Lindgren et al, 2011, JBJS) report adverse reactions to metal debris (ARMD) due to debris produced from the taper-trunnion junction of the modular MoP THRs. A recent retrospective observational study (Matharu et al, 2016, BMC Musc Dis) showed that the risk of ARMD revision surgery is increasing in MoP THRs. To the authors' best knowledge, no hip simulator tests have investigated material loss from the taper-trunnion junction of contemporary MoP THRs. Methods. A 6-station anatomical
Introduction The effect of hip rotation on the measurement of femoral offset is determined firstly using artificial bones in an anatomical study and then in a patient population. Its effect on the choice of femoral component in total hip arthroplasty is discussed. Methods X-rays were taken of a series of saw bone models rotated through a range of angles. The resultant offset was then measured. Standardised and Control (unstandardised) x-rays of the pelvis were taken of patients presenting to orthopaedic outpatients. Femoral offset was measured from each x-ray. Results In the anatomical study angles of rotation differed significantly with respect to measurement of offset (p<
0.0001 Friedman 2-way analysis of variance by ranks). The greatest measurement of offset was at 15 degrees internal rotation. Offset decreased with external rotation. The clinical study had power of 80%. Femoral offset was increased in all the standardised x-rays compared with their controls (n=64, mean=8.68, SD=5.56, 95% CI (7.34,10.01) A one-sample t-test was performed to see if the standardised and control films were greater than 5mm different (t=12.94 (63df), p<
0.01). Conclusions The clinical study confirmed the findings of the anatomical study. A standardised AP x-ray of the pelvis improves the measurement of femoral offset. For surgeons using the Exeter hip system failure to account for offset could lead to the selection of a stem two sizes too small with regards to offset. Lesser degrees of rotation, not readily identified by looking at the x-ray, could still lead to the selection of an incorrectly sized stem. Offset has been shown to increase the range of movement, abductor strength and stability of the
Introduction: Deep infection is a devastating complication following hip arthroplasty. In the early 1970’s Staphylococcus Aureus (SA) was believed to be the causative organism in most cases and Coagulase Negative Staphylococccus (CNS) was widely regarded as a contaminant. It subsequently became recognised that the majority of infections are caused by CNS rather than SA, probably due to the use of peri-operative antimicrobial agents and laminar air flow in theatre. Aims: The aim of this study was to look at the causative organisms in patients with an infected total hip replacement to see if the pattern of infection has changed with time. Methods: Between February 1999 and November 2004, 95 patients underwent 1. st. stage revision surgery at the Northern General Hospital for definite infection following total hip replacement. At least 5 tissue samples were taken at the time of surgery prior to antibiotic administration. Infection was confirmed when at least 3 of the samples were positive on microbiological culture. We retrospectively reviewed the records of these patients and identified the causative organisms. Results: The 95 patients were infected with 130 different organisms. Of these 32% were SA including MRSA (7.2%), 27% CNS, 13.6% Enterococcus, 4.8% pseudomonas and 3.2% Streptococcci. 29% of patients had polymicrobial infection. Discussion: Data published in the literature as well as historical data from our unit suggest that CNS is by far the most common organism causing prosthetic
1. Introduction. Metal-on-metal (MOM)
This is the first time that the principle of the mouldâthe principle of guiding the repair of nature for the purpose of recreating a destroyed or damaged structure, has been applied to surgery. The evolution of the method to its present encouraging stage is the result of the co-operative, professional family spirit of the Massachusetts General Hospital. We all share in it. We share it with the general surgeon because of his contributions to surgical technique. We share it with the "medical man" because of his pre-operative and post-operative care of the patient; because of his guidance as to when, and when not, to operate; and because of the many friendly arguments which are productive of so much good. We share it with the anaesthetist because of his clinical judgment of the patient, his selection of anaesthetic agent, and his continuous, conscientious administration of the anaesthetic throughout the operation. I am going to change from "we" to "I." I owe so much to my assistants, from the first to the last: Bill Rogers, Eddie Cave, George Van Gorder, Paul Norton, Milton Thompson, Otto Aufranc, and Carroll Larson. I want to thank them all for helping to carry the load, for remembering the things that I forgot, and for making helpful suggestions which often led to improvement in surgical technique or to the construction of a useful instrument. I want to pay tribute to the staff of the Orthopaedic Service of the Massachusetts General Hospital and to thank its members for kindly scepticism, constructive criticism, and neverfailing loyal support. The subject of this lecture, "Evolution of Mould Arthroplasty of the
Objective. 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. Methods. Chondral flaps were created in the antero-superior zone of the acetabulum in a series of human cadaveric
Introduction Zero wear of highly crosslinked UHMWPE has been reported in hip simulators (. 1. ). In contrast clinical studies have reported finite wear rates (. 2. ). The aim of this study was to compare the wear rates produced by UHMWPE with different levels of crosslinking in a
The purpose of current study was to describe the results of complex acetabular fractures treated with open reduction using transtrochanteric approach and arthrotomy of the
1. The early signs of Paget's disease of the acetabulum and femur are described. 2. The pattern of arthritis is presented in 199 hips in which Paget's disease of bone occurred in either the femur, the acetabulum or both bones. Distinct patterns of disease occur with different bone involvement. 3. Selective narrowing of the medial segment of the joint is common and is particularly associated with pelvic disease. Why the narrowing occurs here preferentially is unexplained. 4. Protrusio acetabuli occurred in only 25 per cent of hips and usually when both the femur and the acetabulum were involved. This may be due to the presence simultaneously of weakened bone and coxa vara, the latter leading to an alteration in the direction of the resultant force across the
Introduction. Modularity allows surgeons to use femoral heads of various materials, diameters and offsets to achieve the best possible outcome, nevertheless the fretting corrosion behaviour of modular junctions can be significantly affected. The aim of this study was to assess physiological friction moment and lubrication ratio in order to compare various tribological materials against different bearing sizes. This data is important as lubrication will affect the friction, wear and torque generated which may lead directly to the production of debris or to enhanced corrosion at modular junctions. Materials and methods.
Introduction: Perthes disease often leaves young adults with
Background. Prosthetic implants used in primary total hip replacements have a range of bearing surface combinations (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, metal-on-metal); head sizes (small <36mm, large 36mm+); and fixation techniques (cemented, uncemented, hybrid, reverse hybrid), which influence prosthesis survival, patient quality of life, and healthcare costs. This study compared the lifetime cost-effectiveness of implants to determine the optimal choice for patients of different age and gender profiles. Methods. In an economic decision Markov model, the probability that patients required one or more revision surgeries was estimated from analyses of UK and Swedish
The purpose of our presentation is to propose a asimple and reliable method which does not expose the doctor and the patient to radiation for hip arthrocentesis and to be used by inexperienced doctors as well as for studies. Hip Arthrocentesis (HA) on every day practice is performed by the anatomic knowledge and experience. But as a study has shown there is a high failure rate as it concerns the correct position of the needle in the joint, even in joints as the knee and shoulder where the intraarticular injections as usual. According to the American College of Rheumatology hip arthrocentesis should be performed by experienced Rheumatologists, Orthopaedic Surgeons and Radiologists, and always under radiological control. HA at first has been performed for diagnostic purposes, mainly infections, for fluid aspiration. Later for therapeutic reasons (corticosteroids), and for the differential diagnosis between abdominal and osteoarthritic pain of the hip with the intraarticular injection of local anaesthetic. HA under ultrasound control was initially performed in 1989 for diagnostic reasons and later in 2001 has been used for intraarticular injections of Hyalouronic Acid for the treatment of hip osteoarthritis. In the international literature publications about the help that Ultrasonography provides at hip arthrocentesis are sporadic (sparse). Since 2000 we performed 50 intraarticular injections at the
1. Congenital dislocation of the hip can be diagnosed clinically immediately after birth and the diagnosis confirmed radiologically by a special technique. 2. If the affected joint is reduced during the first two or three days after birth and held reduced for a period not exceeding three months, the joint will remain stable. 3. This treatment probably leads to normal development of the
Perthes disease often leaves young adults with
At our institution, periprosthetic
Introduction: Crosslinking has been extensively introduced to reduce the wear of UHMWPE. Zero wear of highly crosslinked UHMWPE has been reported by some groups (. 1. ) in hip simulators, clinical studies have reported finite wear rates (. 2. ). The aim of this study was to compare the wear rates produced by UHMWPE with different levels of crosslinking. Materials and Methods: Studies were carried out using 28mm diameter cobalt chrome femoral heads. These were articulated against UHMWPE in the Leeds ProSim
Aims: The aim of the paper is evaluation of
1. The operation of "dynamic" osteotomy is designed to secure a stable and freely mobile pseudarthrosis in cases of quiescent tuberculosis of the
Introduction: Hip arthroplasty is growing in importance and relevance in the detection and treatment of various pathologies affecting the
1. A lateral intermuscular approach to the
Summary. We found good to excellent reproducibility of in vivo
Introduction and Aims. Clinically many factors such as variations in surgical positioning, and patients' anatomy and biomechanics can affect the occurrence and severity of edge loading which may have detrimental effect on the wear and durability of the implant. Assessing wear of hundreds of combinations of conditions would be impractical, so a preclinical testing approach was followed where the occurrence and severity of edge loading can be determined using short biomechanical tests. Then, selected conditions can be chosen under which the wear can be determined. If a wear correlation with the magnitude of dynamic separation or the severity of edge loading can be shown, then an informed decision can be made based upon the biomechanical results to only select important variables under which the tribological performance of the implant can be assessed. The aim of this study was to determine the relationship between the wear of ceramic-on-ceramic bearings and the (1) magnitude of dynamic separation, (2) the maximum force reached during edge loading and (3) the severity of edge loading resulting from component translational mismatch between the head and cup centres. Methods. The Leeds II
Introduction: Evaluation of the
Arthrodesis of the
INTRODUCTION. Hip wear simulator test results could be affected by many non-bearing related factors such as fixation surface conditions, equipment calibration and component set-up. In an effort to improve the accuracy, reliability and repeatability of hip simulator test, a quality management system has been established at the IDC hip tribology laboratory, which has been accredited by UKAS (United Kingdom Accreditation Service) in accordance with the recognised international standard ISO17025. This study demonstrates that under well-controlled laboratory and testing conditions, satisfactory repeatability can be achieved during hip simulator studies. METHODS. Between 2008 to 2010, ten 50 mm Birmingham Hip Resurfacing (BHR) devices were tested by the IDC tribology laboratory using two ProSim hip wear simulators in three different tests (T1, T2 and T3). All tests were performed following the same IDC testing protocols at 1 Hz frequency for 5 million cycles (Mc) or until after a steady state was reached. Paul type stance phase loadings with a maximum load of 3 kN and a swing phase load of 0.3 kN was used. The flexion and extension angles were 30 and 15 degree. The internal/external rotation angel was ±10 degree. Wear was measured gravimetrically using an analytical balance (Mettler, Toledo xp504) with an accuracy of 0.1 mg. RESULTS. Results showed that wear of all the components tested followed the typical biphasic trend of wear for MoM
Introduction. Postoperative knee flexion is an important indicator of success in total knee arthroplasty (TKA). Factors influencing the postoperative range of motion (ROM) were reported to be preoperative ROM, primary indication, height of postoperative joint line, patellar thickness, postoperative pain and rehabilitation. In this study, we aimed to identify the relationship between preoperative hip ROMs and postoperative knee flexion through reviewing the TKA results in Japanese patients. Patients & Methods. We retrospectively reviewed primary TKAs 55 knees in 55 patients (33 left and 22 right) between April 2012 and March 2013 inclusive. The patients were 11 men and 44 women, with a mean age of 76.7 years. Preoperative hip ROMs and perioperative knee flexion were measured by using goniometer. Hip ROMs were flexion, extension, abduction, adduction, external rotation; ER, internal rotation; IR and total rotation; TR (The total rotation added up ER and IR.). Hip ROMs were measured passively, with the pelvis was fixed manually. Postoperative knee flexion was measured in the fourth week. The patients were classified according to the good group (28 knees), the postoperative knee flexion was more than 125 degrees; and the poor group (27 knees), less than 120 degrees. We compared preoperative hip ROMs in each groups. Multiple regression analysis and Single regression analysis were used for comparison between preoperative hip ROMs and postoperative knee flexion. For comparisons between paired groups we used Wilcoxon test, between unpaired groups Mann-Whitney U test. A p value of less than 0.05 was considered significant. Results. Knee flexion of all patients did not have significant changes before and after the operation (p=0.09). Although the good group was a similar result (p=0.94), the poor group significantly decreased after the operation (p=0.01). (Table 1) The linear combination of hip ER and hip IR explained 28% (R. 2. = 0.28, p=0.0008) of the variance in postoperative knee flexion. The correlation coefficient of postoperative knee flexion and preoperative flexion was 0.41 (p=0.0017), and postoperative knee flexion and hip IR was 0.27(p=0.048), and postoperative knee flexion and hip TR was 0.35(p=0.008). There were only a low correlation between hip ROMs and postoperative knee flexion. (Table 2) As for the hip ER and hip IR, there were no significant differences between good group and poor group, however there was a significant difference for the hip TR between the two groups (p=0.013).(Figure 1). Discussion. The mean postoperative flexion of our patients was 122.4°, with a loss of 2.4° flexion but postoperative flexion was improved on equality with preoperative flexion. There was a positive correlation between preoperative and postoperative flexion. This study also showed that there was a positive correlation between postoperative flexion and preoperative hip TR. A new finding is that there was a significant difference for the hip TR between good group and poor group. These finding may imply that biarticular muscles of origin around
Purpose: Rapidly destructive degeneration of the
The aim was to review patients that had single stage bilateral total hip joint replacements (SSBTHJR) of two surgeons in the Wellington area, to assess symptomatic relief and overall quality of life before and after surgery. To also review xrays of this population to assess acetabular component orientation. Fifty patients from two hospitals, with minimum follow up of two years, who had SSBTHJR, were reviewed for duration of stay, time to mobilisation, and complications (eg. wound infections, venous thrombus and embolism (VTE), gastrointestinal ileus, and cardiac events). Patient opinions on
Over the past fifteen years hip preservation surgery has rapidly evolved. Improved understanding of the pathomechanics and associated intra-articular degeneration of both hip instability and femoroacetabular impingement have led to improved surgical indications, refined surgical techniques and more effective joint preservation surgical procedures. The periacetabular osteotomy (PAO) was initially introduced by Ganz and colleagues and has become the preferred treatment in North America for pre-arthritic, symptomatic acetabular dysplasia. Both hip arthroscopy and safe surgical dislocation of the hip have been popularised for the treatment of symptomatic femoroacetabular impingement disorders. Hip arthroscopy is effective for focal and\or accessible impingement lesions while the surgical dislocation approach is reserved for nonfocal disease patterns as seen in complex FAI, and residual Perthes and SCFE deformities. Femoroacetabular impingement from major acetabular retroversion can be managed with the PAO if there is coexistent posterosuperior acetabular insufficiency. Short- to mid-term results of these procedures are generally good to excellent for most patients and the complication rates associated with these procedures are very acceptable. Long-term outcomes are best known for the PAO. Several recent studies have documented survivorship rates of 65–90% at 10–20-year follow-up. Certain factors are associated with long-term success including minimal pre-operative radiographic OA, early symptoms, accurate acetabular correction, and younger age. These data strongly suggest that the PAO can defer THA to an older age for most patients while completely avoiding arthroplasty may only be possible in select patients with excellent congruency, no secondary OA and an ideal surgical correction.
Large diameter metal on metal hip bearings have been shown to display exceptionally low wear in vivo. However, as these components are often cast, they may be heat treated to improve homogeneity, although it has been suggested that this may adversely affect wear. Therefore a hip simulator study was commissioned to investigate this further. Multi-station hip simulator testing was carried out on 40 mm diameter high carbon cast cobalt chrome alloy components, all having similar radial clearances (~100mm), surface finishes (0.01mm Ra) and sphericity deviations (<
10mm). Three bearing couples were hot isostatic pressed (HIPed) and solution heat treated, generating a fine carbide structure, and three bearing couples were left as cast, creating a coarse carbide structure. All sockets were mounted in an MTS hip simulator, inclined at 35° to the horizontal, and subjected to standard walking conditions (2450 N max) using 25% bovine serum as a test lubricant. Wear was calculated gravimetrically using temperature controls. Running-in wear was observed for both groups generating a similar combined head and cup mean wear rate of 2.3 mm3/106 cycles. The mean steady-state wear rate (SE) for the as cast and HIPed components was 0.38 (0.13) and 0.57 (0.11) mm3/106 cycles respectively showing no statistical difference (p >
0.2). Wear was generally higher for the cups than the heads. These wear rates are two orders of magnitude lower than published wear rates of metal-UHMWP E under similar conditions and one order of magnitude lower than lightly crosslinked UHMWPE articulating against CoCrMo under the same conditions. In this test, the effect of HIPing and solution heat treatment on metal-metal wear would therefore appear to be insignificant. This is in contrast to the published influences of both bearing diameter and bearing tolerances, i.e. sphericity and radial clearance on the wear of metal-metal
The purpose of the research: demonstration of a hip caput matrix modeling opportunities, restoration of a joint stability and joint anatomy improvement in three planes after triple osteotomy of the pelvic by A.M.Sakalouski with Perthes disease patients. Patients and methods: From 1998 to 2007 years were performed 37 triple pelvic osteotomy in 36 patients at 4 to 18 (average age 11 years) with unfavorable course of Perthes disease. In 28 cases patients were male and in 8 cases patients were female. We have observed patients clinically and with radiological methods, including computer tomography with 3D-reconstruction. Indications for pelvic osteotomy include signs of poor prognosis at stages II–III. Radiological signs of risk. The indication to triple pelvic osteotomy on residual stages - this is a secondary acetabular dysplasia and decentration. If the head of a hip is hardly deformed (flat) by the first stage us carried out back or forward rotation hips osteotomy with turn on 70°–90°, and then triple pelvic osteotomy. Results: The triple osteotomy of the pelvic prevented deformation of the head of a hip at e at 2–3 stages as a result remodeling of femoral caput by spherical acetabulum. At late stages operation has provide to avoid hip arthrosis. Medialization of the
We aimed to determine if there are mechanoreceptors in
There are a number of progressive conditions that afflict the hip and result in degenerative arthritis. Along the path of progression of the disease and prior to the development of arthritis, some of these conditions may be treatable by joint preservation procedures. Periacetabular osteotomy for developmental dysplasia of the hip (DDH), femoroacetabular osteoplasty for femoroacetabular impingement (FAI), and a variety of surgical procedures for management of early osteonecrosis of the femoral head are some examples of joint preservation of the hip. DDH is characterised by abnormal development of the acetabulum and the proximal femur that leads to suboptimal contact of the articular surfaces and the resultant increase in joint reaction forces. FAI is a condition characterised by an abnormal contact between the femoral neck and the acetabular rim. FAI is believed to exist when a triad of signs (abnormal alpha angle, labral tear, and chondral lesion) can be identified. The question that remains is whether joint preservation procedures are able to avert the need for arthroplasty or just an intervention along the natural path of progression of the hip disease. There is an interesting study that followed 628 infants born in a Navajo reservation, including 8 infants with severe dysplasia, for 35 years. None of the children with DDH had surgical treatment and all had developed severe arthritis in the interim. The latter study and a few other natural history studies have shown that the lack of administration of surgical treatment to patients with symptomatic DDH results in accelerated arthritis. The situation is not so clear with FAI. Some believe that FAI is a pre-arthritic condition and surgical treatment is only effective in addressing the symptoms and does not delay or defer an arthroplasty. While others believe that restoration of the normal mechanical environment to the hip of FAI patients, by removing the abnormal contact and repair of the labrum, is likely to change the natural history of the disease and at minimum delay the need for an arthroplasty. There is a need for natural history studies or case series to settle the latter controversy.
Background/Objective: Since estrogen receptors (ERα/ERβ) were identified in human chondrocytes, animal-and experimental studies have demonstrated the importance of continued estrogen production for the integrity of articular cartilage. However, human epidemiological support of the hypothesis has been inconclusive. The present study investigated the relationship between reduced bone mineral densities (BMD), as a surrogate parameter of endogenous estrogen status – assessed by digital x-ray radiogrammetry (DXR), and reduced minimum
Introduction: The