Aims. The main advantage of 3D-printed, off-the-shelf
Aims. Post-traumatic periprosthetic acetabular fractures are rare but serious. Few studies carried out on small cohorts have reported them in the literature. The aim of this work is to describe the specific characteristics of post-traumatic periprosthetic acetabular fractures, and the outcome of their surgical treatment in terms of function and complications. Methods. Patients with this type of fracture were identified retrospectively over a period of six years (January 2016 to December 2021). The following data were collected: demographic characteristics, date of insertion of the prosthesis, details of the intervention, date of the trauma, characteristics of the fracture, and type of treatment. Functional results were assessed with the Harris Hip Score (HHS). Data concerning complications of treatment were collected. Results. Our series included 20 patients, with a mean age of 77 years (46 to 90). All the patients had at least one comorbid condition. Radiographs showed that 75% of the fractures were pure transverse fractures, and a transverse component was present in 90% of patients. All our patients underwent surgical treatment: open reduction and internal fixation, revision of the acetabular component, or both. Mean follow-up was 24 months, and HHS at last follow-up was 75.5 (42 to 95). The principal complications observed were dislocations of the prosthesis (30%) and infections (20%). A need for revision surgery was noted in 30% of patients. No dislocation occurred in patients undergoing osteosynthesis with acetabular reconstruction. We did not note either mechanical loosening of the acetabular component nor thromboembolic complications. In all, 30% of patients presented acute anemia requiring transfusion, and one death was reported. Conclusion. Post-traumatic periprosthetic acetabular fractures frequently have a transverse component that can destabilize the
Aims. Pelvic discontinuity is a rare but increasingly common complication of total hip arthroplasty (THA). This single-centre study evaluated the performance of custom-made triflange acetabular components in acetabular reconstruction with pelvic discontinuity by determining: 1) revision and overall implant survival rates; 2) discontinuity healing rate; and 3) Harris Hip Score (HHS). Methods. Retrospectively collected data of 38 patients (39 hips) with pelvic discontinuity treated with revision THA using a custom-made triflange acetabular component were analyzed. Minimum follow-up was two years (mean 5.1 years (2 to 11)). Results. There were eight subsequent surgical interventions. Two failures (5%) of the triflange acetabular components were both revised because of deep infection. There were seven (18%) patients with dislocation, and five (13%) of these were treated with a constraint liner. One patient had a debridement, antibiotics, and implant retention (DAIR) procedure. In 34 (92%) hips the custom-made triflange component was considered stable, with a healed pelvic discontinuity with no aseptic loosening at midterm follow-up. Mean HHS was 80.5 (48 to 96). Conclusion. The performance of the custom triflange implant in this study is encouraging, with high rates of discontinuity healing and osteointegration of the
Aims. Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. Methods. We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic
Aims. Uncemented metal acetabular components show good osseointegration, but material stiffness causes stress shielding and retroacetabular bone loss. Cemented monoblock polyethylene components load more physiologically; however, the cement bone interface can suffer fibrous encapsulation and loosening. It was hypothesized that an uncemented titanium-sintered monoblock polyethylene component may offer the optimum combination of osseointegration and anatomical loading. Methods. A total of 38 patients were prospectively enrolled and received an uncemented monoblock polyethylene acetabular (pressfit) component. This single cohort was then retrospectively compared with previously reported randomized cohorts of cemented monoblock (cemented) and trabecular metal (trabecular)
Aims. Periprosthetic fracture and implant loosening are two of the major reasons for revision surgery of cementless implants. Optimal implant fixation with minimal bone damage is challenging in this procedure. This pilot study investigates whether vibratory implant insertion is gentler compared to consecutive single blows for
Custom triflange acetabular components (CTACs) play an important role in reconstructive orthopaedic surgery, particularly in revision total hip arthroplasty (rTHA) and pelvic tumour resection procedures. Accurate CTAC positioning is essential to successful surgical outcomes. While prior studies have explored CTAC positioning in rTHA, research focusing on tumour cases and implant flange positioning precision remains limited. Additionally, the impact of intraoperative navigation on positioning accuracy warrants further investigation. This study assesses CTAC positioning accuracy in tumour resection and rTHA cases, focusing on the differences between preoperative planning and postoperative implant positions. A multicentre observational cohort study in Australia between February 2017 and March 2021 included consecutive patients undergoing acetabular reconstruction with CTACs in rTHA (Paprosky 3A/3B defects) or tumour resection (including Enneking P2 peri-acetabular area). Of 103 eligible patients (104 hips), 34 patients (35 hips) were analyzed.Aims
Methods
The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system. This study included 30 CO THAs versus 30 RO THAs performed by a single surgeon. Intraoperative photographs of the osseous acetabulum and periacetabular soft-tissues were obtained prior to implantation of the acetabular component, which were used to develop the proposed classification system. Interobserver and intraobserver variabilities of the proposed classification system were assessed.Aims
Methods
Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed.Aims
Methods
Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon. A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records.Aims
Methods
Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct. We identified 64 patients (65 hips) who had a single-design cemented DM cup cemented into an uncemented acetabular shell during revision THA between 2018 and 2020 at our institution. Cups were cemented into either uncemented cups designed for liner cementing (n = 48; 74%) or retained (n = 17; 26%) acetabular components. Median outer head diameter was 42 mm. Mean age was 69 years (SD 11), mean BMI was 32 kg/m2 (SD 8), and 52% (n = 34) were female. Survival was assessed using Kaplan-Meier methods. Mean follow-up was two years (SD 0.97).Aims
Methods
The aim of this study was to assess the clinical and radiological results of patients who were revised using a custom-made triflange acetabular component (CTAC) for component loosening and pelvic discontinuity (PD) after previous total hip arthroplasty (THA). Data were extracted from a single centre prospective database of patients with PD who were treated with a CTAC. Patients were included if they had a follow-up of two years. The Hip Disability and Osteoarthritis Outcome Score (HOOS), modified Oxford Hip Score (mOHS), EurQol EuroQoL five-dimension three-level (EQ-5D-3L) utility, and Numeric Rating Scale (NRS), including visual analogue score (VAS) for pain, were gathered at baseline, and at one- and two-year follow-up. Reasons for revision, and radiological and clinical complications were registered. Trends over time are described and tested for significance and clinical relevance.Aims
Methods
Although the Fitmore Hip Stem has been on the market for almost 15 years, it is still not well documented in randomized controlled trials. This study compares the Fitmore stem with the CementLeSs (CLS) in several different clinical and radiological aspects. The hypothesis is that there will be no difference in outcome between stems. In total, 44 patients with bilateral hip osteoarthritis were recruited from the outpatient clinic at a single tertiary orthopaedic centre. The patients were operated with bilateral one-stage total hip arthroplasty. The most painful hip was randomized to either Fitmore or CLS femoral component; the second hip was operated with the femoral component not used on the first side. Patients were evaluated at three and six months and at one, two, and five years postoperatively with patient-reported outcome measures, radiostereometric analysis, dual-energy X-ray absorptiometry, and conventional radiography. A total of 39 patients attended the follow-up visit at two years (primary outcome) and 35 patients at five years. The primary outcome was which hip the patient considered to have the best function at two years.Aims
Methods
Aims. The aim of the study was to investigate whether the primary stability of press-fit acetabular components can be improved by altering the impaction procedure. Methods. Three impaction procedures were used to
Iliopsoas impingement occurs in 4% to 30% of patients after undergoing total hip arthroplasty (THA). Despite a relatively high incidence, there are few attempts at modelling impingement between the iliopsoas and acetabular component, and no attempts at modelling this in a representative cohort of subjects. The purpose of this study was to develop a novel computational model for quantifying the impingement between the iliopsoas and acetabular component and validate its utility in a case-controlled investigation. This was a retrospective cohort study of patients who underwent THA surgery that included 23 symptomatic patients diagnosed with iliopsoas tendonitis, and 23 patients not diagnosed with iliopsoas tendonitis. All patients received postoperative CT imaging, postoperative standing radiography, and had minimum six months’ follow-up. 3D models of each patient’s prosthetic and bony anatomy were generated, landmarked, and simulated in a novel iliopsoas impingement detection model in supine and standing pelvic positions. Logistic regression models were implemented to determine if the probability of pain could be significantly predicted. Receiver operating characteristic curves were generated to determine the model’s sensitivity, specificity, and area under the curve (AUC).Aims
Methods
The aim of this study was to examine the implant accuracy of custom-made partial pelvis replacements (PPRs) in revision total hip arthroplasty (rTHA). Custom-made implants offer an option to achieve a reconstruction in cases with severe acetabular bone loss. By analyzing implant deviation in CT and radiograph imaging and correlating early clinical complications, we aimed to optimize the usage of custom-made implants. A consecutive series of 45 (2014 to 2019) PPRs for Paprosky III defects at rTHA were analyzed comparing the preoperative planning CT scans used to manufacture the implants with postoperative CT scans and radiographs. The anteversion (AV), inclination (IC), deviation from the preoperatively planned implant position, and deviation of the centre of rotation (COR) were explored. Early postoperative complications were recorded, and factors for malpositioning were sought. The mean follow-up was 30 months (SD 19; 6 to 74), with four patients lost to follow-up.Aims
Methods
We have undertaken a prospective, randomised study to compare conservation of acetabular bone after total hip replacement and resurfacing arthroplasty of the hip. We randomly assigned 210 hips to one of the two treatment groups. Uncemented, press-fit acetabular components were used for both. No significant difference was found in the mean diameter of
Although CT is considered the benchmark to measure femoral version, 3D biplanar radiography (hipEOS) has recently emerged as a possible alternative with reduced exposure to ionizing radiation and shorter examination time. The aim of our study was to evaluate femoral stem version in postoperative total hip arthroplasty (THA) patients and compare the accuracy of hipEOS to CT. We hypothesize that there will be no significant difference in calculated femoral stem version measurements between the two imaging methods. In this study, 45 patients who underwent THA between February 2016 and February 2020 and had both a postoperative CT and EOS scan were included for evaluation. A fellowship-trained musculoskeletal radiologist and radiological technician measured femoral version for CT and 3D EOS, respectively. Comparison of values for each imaging modality were assessed for statistical significance.Aims
Methods
Aims. The aim of this study was to analyze the effect of a lateral rim mesh on the survival of primary total hip arthroplasty (THA) in young patients, aged 50 years or younger. Patients and Methods. We compared a study group of 235 patients (257 hips) who received a primary THA with the use of impaction bone grafting (IBG) with an additional lateral rim mesh with a group of 306 patients (343 hips) who received IBG in the absence of a lateral rim mesh during the same period from 1988 to 2015. In the mesh group, there were 74 male and 183 female patients, with a mean age of 35 years (13 to 50). In the no-mesh group, there were 173 male and 170 female patients, with a mean age of 38 years (12.6 to 50). Cox regression analyses were performed to study the effect of a lateral rim mesh on acetabular component survival. Kaplan–Meier analyses with 95% confidence intervals (CIs) were performed to estimate the survival of the
In computer simulations, the shape of the range of motion (ROM) of a stem with a cylindrical neck design will be a perfect cone. However, many modern stems have rectangular/oval-shaped necks. We hypothesized that the rectangular/oval stem neck will affect the shape of the ROM and the prosthetic impingement. Total hip arthroplasty (THA) motion while standing and sitting was simulated using a MATLAB model (one stem with a cylindrical neck and one stem with a rectangular neck). The primary predictor was the geometry of the neck (cylindrical vs rectangular) and the main outcome was the shape of ROM based on the prosthetic impingement between the neck and the liner. The secondary outcome was the difference in the ROM provided by each neck geometry and the effect of the pelvic tilt on this ROM. Multiple regression was used to analyze the data.Aims
Methods
We evaluated the accuracy with which a custom-made
acetabular component could be positioned at revision arthroplasty
of the hip in patients with a Paprosky type 3 acetabular defect. A total of 16 patients with a Paprosky type 3 defect underwent
revision surgery using a custom-made trabecular titanium implant.
There were four men and 12 women with a median age of 67 years (48
to 79). The planned inclination (INCL), anteversion (AV), rotation
and centre of rotation (COR) of the implant were compared with the post-operative
position using CT scans. A total of seven implants were malpositioned in one or more parameters:
one with respect to INCL, three with respect to AV, four with respect
to rotation and five with respect to the COR. To the best of our knowledge, this is the first study in which
CT data acquired for the pre-operative planning of a custom-made
revision
Prior studies have identified that malseating of a modular dual mobility liner can occur, with previous reported incidences between 5.8% and 16.4%. The aim of this study was to determine the incidence of malseating in dual mobility implants at our institution, assess for risk factors for liner malseating, and investigate whether liner malseating has any impact on clinical outcomes after surgery. We retrospectively reviewed the radiographs of 239 primary and revision total hip arthroplasties with a modular dual mobility liner. Two independent reviewers assessed radiographs for each patient twice for evidence of malseating, with a third observer acting as a tiebreaker. Univariate analysis was conducted to determine risk factors for malseating with Youden’s index used to identify cut-off points. Cohen’s kappa test was used to measure interobserver and intraobserver reliability.Aims
Methods
We aimed to evaluate the long-term outcome of highly cross-linked polyethylene (HXLPE) cemented acetabular components and assess whether any radiolucent lines (RLLs) which arose were progressive. We retrospectively reviewed 170 patients who underwent 187 total hip arthroplasties at two hospitals with a minimum follow-up of ten years. All interventions were performed using the same combination of HXLPE cemented acetabular components with femoral stems made of titanium alloy. Kaplan-Meier survival analysis was performed for the primary endpoint of acetabular component revision surgery for any reason and secondary endpoint of the appearance of RLLs. RLLs that had appeared once were observed over time. We statistically assessed potential relationships between RLLs and a number of factors, including the technique of femoral head autografting and the Japanese Orthopaedic Association score.Aims
Methods
There is a paucity of long-term studies analyzing risk factors for failure after single-stage revision for periprosthetic joint infection (PJI) following total hip arthroplasty (THA). We report the mid- to long-term septic and non-septic failure rate of single-stage revision for PJI after THA. We retrospectively reviewed 88 cases which met the Musculoskeletal Infection Society (MSIS) criteria for PJI. Mean follow-up was seven years (1 to 14). Septic failure was diagnosed with a Delphi-based consensus definition. Any reoperation for mechanical causes in the absence of evidence of infection was considered as non-septic failure. A competing risk regression model was used to evaluate factors associated with septic and non-septic failures. A Kaplan-Meier estimate was used to analyze mortality.Aims
Methods
Between January 1998 and December 1998, 82 consecutive patients (86 hips) underwent total hip arthroplasty using a trabecular metal monoblock acetabular component. All patients had a clinical and radiological follow-up evaluation at six, 12 and 24 weeks, 12 months, and then annually thereafter. On the initial post-operative radiograph 25 hips had a gap between the outer surface of the component and the acetabular host bed which ranged from 1 to 5 mm. All patients were followed up clinically and radiologically for a mean of 7.3 years (7 to 7.5). The 25 hips with the 1 to 5 mm gaps were studied for component migration at two years using the Einzel-Bild-Roentgen-Analyse (EBRA) digital measurement method. At 24 weeks all the post-operative gaps were filled with bone and no acetabular component had migrated. The radiographic outcome of all 86 components showed no radiolucent lines and no evidence of lysis. No
Morphological abnormalities are present in patients with developmental dysplasia of the hip (DDH). We studied and compared the pelvic anatomy and morphology between the affected hemipelvis with the unaffected side in patients with unilateral Crowe type IV DDH using 3D imaging and analysis. A total of 20 patients with unilateral Crowe-IV DDH were included in the study. The contralateral side was considered normal in all patients. A coordinate system based on the sacral base (SB) in a reconstructed pelvic model was established. The pelvic orientations (tilt, rotation, and obliquity) of the affected side were assessed by establishing a virtual anterior pelvic plane (APP). The bilateral coordinates of the anterior superior iliac spine (ASIS) and the centres of hip rotation were established, and parameters concerning size and volume were compared for both sides of the pelvis.Aims
Methods
To compare long-term survival of all-cemented and hybrid total hip arthroplasty (THA) using the Exeter Universal stem. Details of 1,086 THAs performed between 1999 and 2005 using the Exeter stem and either a cemented (632) or uncemented acetabular component (454) were collected from local records and the New Zealand Joint Registry. A competing risks regression survival analysis was performed with death as the competing risk with adjustments made for age, sex, approach, and bearing.Aims
Methods
Despite advances in the treatment of paediatric hip disease, adolescent and young adult patients can develop early onset end-stage osteoarthritis. The aims of this study were to address the indications and medium-term outcomes for total hip arthroplasty (THA) with ceramic bearings for teenage patients. Surgery was performed by a single surgeon working in the paediatric orthopaedic unit of a tertiary referral hospital. Databases were interrogated from 2003 to 2017 for all teenage patients undergoing THA with a minimum 2.3 year follow-up. Data capture included patient demographics, the underlying hip pathology, number of previous surgeries, and THA prostheses used. Institutional ethical approval was granted to contact patients for prospective clinical outcomes and obtain up-to-date radiographs. In total, 60 primary hips were implanted in 51 patients (35 female, 16 male) with nine bilateral cases. The mean age was 16.7 years (12 to 19) and mean follow-up was 9.3 years (2.3 to 16.8).Aims
Methods
Pre-operative computerised three-dimensional planning was carried out in 223 patients undergoing total hip replacement with a cementless acetabular component and a cementless modular-neck femoral stem. Components were chosen which best restored leg length and femoral offset. The post-operative restoration of the anatomy was assessed by CT and compared with the pre-operative plan. The component implanted was the same as that planned in 86% of the hips for the
We describe the survivorship of the Exeter femoral component in a District General Hospital. Between 1994 and 1996, 230 Exeter Universal cemented femoral components were implanted in 215 patients who were reviewed at a mean of 11.2 years (10 to 13). We used one
This single-centre observational study aimed to describe the results of extensive bone impaction grafting of the whole acetabular cavity in combination with an uncemented component in acetabular revisions performed in a standardized manner since 1993. Between 1993 and 2013, 370 patients with a median age of 72 years (interquartile range (IQR) 63 to 79 years) underwent acetabular revision surgery. Of these, 229 were more than ten years following surgery and 137 were more than 15 years. All revisions were performed with extensive use of morcellized allograft firmly impacted into the entire acetabular cavity, followed by insertion of an uncemented component with supplementary screw fixation. All types of reoperation were captured using review of radiographs and medical charts, combined with data from the local surgical register and the Swedish Hip Arthroplasty Register.Aims
Methods
Complex total hip arthroplasty (THA) with subtrochanteric shortening osteotomy is necessary in conditions other than developmental dysplasia of the hip (DDH) and septic arthritis sequelae with significant proximal femur migration. Our aim was to evaluate the hip centre restoration with THAs in these hips. In all, 27 THAs in 25 patients requiring THA with femoral shortening between 2012 and 2019 were assessed. Bilateral shortening was required in two patients. Subtrochanteric shortening was required in 14 out of 27 hips (51.9%) with aetiology other than DDH or septic arthritis. Vertical centre of rotation (VCOR), horizontal centre of rotation, offset, and functional outcome was calculated. The mean followup was 24.4 months (5 to 92 months).Aims
Methods
We have evaluated the results of total hip replacement in patients with congenital hip disease using 46 cemented all-polyethylene Charnley
Radiostereometric analysis (RSA) studies of vitamin E-doped, highly crosslinked polyethylene (VEPE) liners show low head penetration rates in cementless acetabular components. There is, however, currently no data on cemented VEPE acetabular components in total hip arthroplasty (THA). The aim of this study was to evaluate the safety of a new cemented VEPE component, compared with a conventional polyethylene (PE) component regarding migration, head penetration, and clinical results. We enrolled 42 patients (21 male, 21 female) with osteoarthritis and a mean age of 67 years (Aims
Patients and Methods
Aims . The highly cross-linked polyethylene Exeter RimFit flanged cemented
acetabular component was introduced in the United Kingdom in 2010.
This study aimed to examine the rates of emergence of radiolucent
lines observed when the Rimfit acetabular component was implanted
at total hip arthroplasty (THA) using two different techniques: firstly,
the ‘rimcutter’ technique in which the flange sits on a pre-prepared
acetabular rim; and secondly, the ‘trimmed flange’ technique in
which the flange is trimmed and the acetabular component is seated
inside the rim of the acetabulum. . Patients and Methods . The radiographs of 150 THAs (75 ‘rimcutter’, 75 ‘trimmed flange’)
involving this component were evaluated to assess for radiolucencies
at the cement/bone interface by three observers. . Results . Rimfit
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
The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual total hip arthroplasty (THA) This prospective cohort study included 50 patients undergoing conventional manual THA and 25 patients receiving robotic-arm assisted THA. Patients undergoing conventional manual THA and robotic-arm assisted THA were well matched for age (mean age, 69.4 years (Objectives
Materials and Methods
Modern metal-on-metal (MoM) hip resurfacing arthroplasty (HRA), while achieving good results with well-orientated, well-designed components in ideal patients, is contraindicated in women, men with head size under 50 mm, or metal hypersensitivity. These patients currently have no access to the benefits of HRA. Highly crosslinked polyethylene (XLPE) has demonstrated clinical success in total hip arthroplasty (THA) and, when used in HRA, potentially reduces metal ion-related sequelae. We report the early performance of HRA using a direct-to-bone cementless mono-bloc XLPE component coupled with a cobalt-chrome femoral head, in the patient group for whom HRA is currently contraindicated. This is a cross-sectional, observational assessment of 88 consecutive metal-on-XLPE HRAs performed in 84 patients between 2015 and 2018 in three centres (three surgeons, including the designer surgeon). Mean follow-up is 1.6 years (0.7 to 3.9). Mean age at operation was 56 years (Objectives
Methods
Resurfacing arthroplasty of the hip is being performed more frequently in the United Kingdom. The majority of these patients are younger than 55 years of age, and in this group the key benefits include conservation of femoral bone stock and the potential reduction in the rate of dislocation afforded by the larger resurfacing head. Early aseptic loosening is well recognised in patients younger than 55 years of age, and proponents of resurfacing believe that the improved wear characteristics of the metal-on-metal bearing may improve the long-term survival of this implant. There has been some concern, however, that resurfacing may not be conservative of acetabular bone. We compared a series of 33 consecutive patients who had a hybrid total hip arthroplasty with an uncemented acetabular component and a cemented femoral implant, with 35 patients undergoing a Birmingham hip resurfacing arthroplasty. We compared the diameter of the implanted acetabulum in both groups and, because they were not directly comparable, we corrected for patient size by measuring the diameter of the contralateral femoral head. The data were analysed using unpaired t-tests and analysis of covariance. There was a significantly larger acetabulum in the Birmingham arthroplasty group (mean diameter 56.6 mm vs 52.0 mm; p <
0.001). However, this group had a significantly larger femoral head diameter on the contralateral side (p = 0.03). Analysis of covariance revealed a significant difference between the mean size of the
There remains confusion in the literature with regard to the spinopelvic relationship, and its contribution to ideal acetabular component position. Critical assessment of the literature has been limited by use of conflicting terminology and definitions of new concepts that further confuse the topic. In 2017, the concept of a Hip-Spine Workgroup was created with the first meeting held at the American Academy of Orthopedic Surgeons Annual Meeting in 2018. The goal of this workgroup was to first help standardize terminology across the literature so that as a topic, multiple groups could produce literature that is immediately understandable and applicable. This consensus review from the Hip-Spine Workgroup aims to simplify the spinopelvic relationship, offer hip surgeons a concise summary of available literature, and select common terminology approved by both hip surgeons and spine surgeons for future research. Cite this article:
The purpose of this retrospective study was to evaluate the minimum
five-year outcome of revision total hip arthroplasty (THA) using
the Kerboull acetabular reinforcement device (KARD) in patients
with Paprosky type III acetabular defects and destruction of the
inferior margin of the acetabulum. We identified 36 patients (37 hips) who underwent revision THA
under these circumstances using the KARD, fresh frozen allograft
femoral heads, and reconstruction of the inferior margin of the
acetabulum. The Merle d’Aubigné system was used for clinical assessment.
Serial anteroposterior pelvic radiographs were used to assess migration
of the acetabular component.Aims
Patients and Methods
Between November 1997 and December 2000 we performed 27 total hip replacements in 22 patients with high congenital dislocation of the hip using porous tantalum monoblock
The aim of this study was to determine whether there is a difference
in the rate of wear between acetabular components positioned within
and outside the ‘safe zones’ of anteversion and inclination angle. We reviewed 100 hips in 94 patients who had undergone primary
total hip arthroplasty (THA) at least ten years previously. Patients
all had the same type of acetabular component with a bearing couple
which consisted of a 28 mm cobalt-chromium head on a highly crosslinked
polyethylene (HXLPE) liner. A supine radiostereometric analysis
(RSA) examination was carried out which acquired anteroposterior
(AP) and lateral paired images. Acetabular component anteversion
and inclination angles were measured as well as total femoral head
penetration, which was divided by the length of implantation to
determine the rate of polyethylene wear.Aims
Patients and Methods
The aims of this study were to determine the clinical and radiographic
outcomes, implant survivorship, and complications of patients with
a history of poliomyelitis undergoing total hip arthroplasty (THA)
in affected limbs and unaffected limbs of this same population. A retrospective review identified 51 patients (27 male and 24
female, 59 hips) with a mean age of 66 years (38 to 88) and with
the history of poliomyelitis who underwent THA for degenerative
arthritis between 1970 and 2012. Immigrant status, clinical outcomes,
radiographic results, implant survival, and complications were recorded.Aims
Patients and Methods
We have reviewed 70 Harris-Galante uncemented
In order to address acetabular defects, porous metal revision acetabular components and augments have been developed, which require fixation to each other. The fixation technique that results in the smallest relative movement between the components, as well as its influence on the primary stability with the host bone, have not previously been determined. A total of 18 composite hemipelvises with a Paprosky IIB defect were implanted using a porous titanium 56 mm multihole acetabular component and 1 cm augment. Each acetabular component and augment was affixed to the bone using two screws, while the method of fixation between the acetabular component and augment varied for the three groups of six hemipelvises: group S, screw fixation only; group SC, screw plus cement fixation; group C, cement fixation only. The implanted hemipelvises were cyclically loaded to three different loading maxima (0.5 kN, 0.9 kN, and 1.8 kN).Objectives
Methods
Reconstruction of the acetabulum after resection of a periacetabular
malignancy is technically challenging and many different techniques
have been used with varying success. Our aim was to prepare a systematic
review of the literature dealing with these techniques in order
to clarify the management, the rate of complications and the outcomes. A search of PubMed and MEDLINE was conducted for English language
articles published between January 1990 and February 2017 with combinations
of key search terms to identify studies dealing with periacetabular
resection with reconstruction in patients with a malignancy. Studies
in English that reported radiographic or clinical outcomes were
included. Data collected from each study included: the number and
type of reconstructions, the pathological diagnosis of the lesions,
the mean age and follow-up, gender distribution, implant survivorship, complications,
functional outcome, and mortality. The results from individual studies
were combined for the general analysis, and then grouped according
to the type of reconstruction. Aims
Patients and Methods
The aim of this study was to examine the results of the acetabular
distraction technique in achieving implantation of a stable construct,
obtaining biological fixation, and producing healing of chronic
pelvic discontinuity at revision total hip arthroplasty. We identified 32 patients treated between 2006 and 2013 who underwent
acetabular revision for a chronic pelvic discontinuity using acetabular
distraction, and who were radiographically evaluated at a mean of
62 months (25 to 160). Of these patients, 28 (87.5%) were female.
The mean age at the time of revision was 67 years (44 to 86). The patients
represented a continuous series drawn from two institutions that
adhered to an identical operative technique.Aims
Patients and Methods
This review summarises the technique of impaction
grafting with mesh augmentation for the treatment of uncontained
acetabular defects in revision hip arthroplasty. The ideal acetabular revision should restore bone stock, use
a small socket in the near-anatomic position, and provide durable
fixation. Impaction bone grafting, which has been in use for over
40 years, offers the ability to achieve these goals in uncontained
defects. The precepts of modern, revision impaction grafting are
that the segmental or cavitary defects must be supported with a
mesh; the contained cavity is filled with vigorously impacted morselised
fresh-frozen allograft; and finally, acrylic cement is used to stabilise
the graft and provide rigid, long-lasting fixation of the revised
acetabular component. Favourable results have been published with this technique. While
having its limitations, it is a viable option to address large acetabular
defects in revision arthroplasty. Cite this article:
A contact patch to rim (CPR) distance of <
10 mm has been
associated with edge-loading and excessive wear. However, not all
arthroplasties with a low CPR distance show problems with wear.
Therefore, CPR distance may not be the only variable affecting the
post-operative metal ion concentrations. We used multiple logistic regression to determine what variables
differed between the patients who had high and low cobalt (CoS)
and chromium (CrS) serum ion concentrations within a cohort of patients
with low (<
10 mm) CPR distances. A total of 56 patients treated
with unilateral hip resurfacing arthroplasty (HRA) had CoS and CrS
ion studies performed more than one year after surgery. The mean
age of the patients at the time of surgery was 51.7 years (29 to
70), with 38 women (68%) and 18 men (32%).Aims
Patients and Methods
Periprosthetic fracture (PF) after primary total hip arthroplasty
(THA) is an uncommon but potentially devastating complication. This
study aims to investigate the influence of cemented stem designs
on the risk of needing a revision for a PF. We analysed data on 257 202 primary THAs with cemented stems
and 390 linked first revisions for PF recorded in the National Joint
Registry (NJR) of England, Wales and Northern Ireland to determine
if a cemented femoral stem brand was associated with the risk of
having revision for a PF after primary THA. All cemented femoral
stem brands with more than 10 000 primary operations recorded in
the NJR were identified. The four most commonly used cemented femoral
stems were the Exeter V40 (n = 146 409), CPT (n = 24 300), C-Stem
(n = 15 113) and Charnley (n = 20 182). We compared the revision risk ratios due to PF amongst the stems
using a Poisson regression model adjusting for patient factors.
Compared with the Exeter V40, the age, gender and ASA grade adjusted
revision rate ratio was 3.89 for the cemented CPT stem (95% confidence
interval (CI) 3.07 to 4.93), 0.89 for the C-Stem (95% CI 0.57 to
1.41) and 0.41 for the Charnley stem (95% CI 0.24 to 0.70).Aims
Patients and Methods
We hypothesised that the removal of the subchondral
bone plate (SCBP) for cemented acetabular component fixation in
total hip arthroplasty (THA) offers advantages over retention by
improving the cement-bone interface, without jeopardising implant
stability. We have previously published two-year follow-up data
of a randomised controlled trial (RCT), in which 50 patients with
primary osteoarthritis were randomised to either retention or removal
of the SCBP. The mean age of the retention group (n = 25, 13 males)
was 70.0 years ( Cite this article:
This study reports the results of 38 total hip
arthroplasties (THAs) in 33 patients aged <
50 years, using the
JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component.
This represents an update of previous reports of the same cohort
at ten and 16 years, which were reported in 2004 and 2009, respectively.
We describe the survival, radiological and functional outcomes at
a mean follow-up of 21 years (17 to 25). Of the surviving 34 THAs,
one underwent femoral revision for peri-prosthetic fracture after
21 years, and one patient (one hip) was lost to follow-up. Using
aseptic loosening as the end-point, 12 hips (31.5%) needed acetabular
revision but none needed femoral revision, demonstrating 100% survival
(95% confidence interval 89 to 100). In young patients with high demands, the Furlong HAC–coated femoral
component gives excellent long-term results. Cite this article:
In this retrospective study we evaluated the
proficiency of shelf autograft in the restoration of bone stock
as part of primary total hip replacement (THR) for hip dysplasia,
and in the results of revision arthroplasty after failure of the primary
arthroplasty. Of 146 dysplastic hips treated by THR and a shelf
graft, 43 were revised at an average of 156 months, 34 of which
were suitable for this study (seven hips were excluded because of
insufficient bone-stock data and two hips were excluded because
allograft was used in the primary THR). The acetabular bone stock
of the hips was assessed during revision surgery. The mean implant–bone
contact was 58% (50% to 70%) at primary THR and 78% (40% to 100%)
at the time of the revision, which was a significant improvement
(p <
0.001). At primary THR all hips had had a segmental acetabular
defect >
30%, whereas only five (15%) had significant segmental
bone defects requiring structural support at the time of revision.
In 15 hips (44%) no bone graft or metal augments were used during
revision. A total of 30 hips were eligible for the survival study. At a
mean follow-up of 103 months (27 to 228), two aseptic and two septic
failures had occurred. Kaplan-Meier survival analysis of the revision
procedures demonstrated a ten-year survival rate of 93.3% (95% confidence
interval (CI) 78 to 107) with clinical or radiological failure as
the endpoint. The mean Oxford hip score was 38.7 (26 to 46) for
non-revised cases at final follow-up. Our results indicate that the use of shelf autografts during
THR for dysplastic hips restores bone stock, contributing to the
favourable survival of the revision arthroplasty should the primary
procedure fail. Cite this article:
Acetabular bone loss is a challenging problem
facing the revision total hip replacement surgeon. Reconstruction
of the acetabulum depends on the presence of anterosuperior and
posteroinferior pelvic column support for component fixation and
stability. The Paprosky classification is most commonly used when
determining the location and degree of acetabular bone loss. Augments
serve the function of either providing primary construct stability
or supplementary fixation. When a pelvic discontinuity is encountered we advocate the use
of an acetabular distraction technique with a jumbo cup and modular
porous metal acetabular augments for the treatment of severe acetabular
bone loss and associated chronic pelvic discontinuity. Cite this article:
In 2005, we demonstrated that the polished triple-tapered
C-stem at two years had migrated distally and rotated internally.
From that series, 33 patients have now been followed radiologically,
clinically and by radiostereometric analysis (RSA) for up to ten
years. The distal migration within the cement mantle had continued
and reached a mean of 2 mm (0.5 to 4.0) at ten years. Internal rotation,
also within the cement mantle, was a mean 3.8° (external 1.6° to
internal 6.6°) The cement mantle did not show any sign of migration
or loosening in relation to the femoral bone. There were no clinical
or radiological signs indicating that the migration or rotation
within the cement mantle had had any adverse effects for the patients. Cite this article:
Large-head metal-on-metal (MoM) total hip replacements
(THR) have given rise to concern. Comparative studies of small-head
MoM THRs over a longer follow-up period are lacking. Our objective
was to compare the incidence of complications such as infection,
dislocation, revision, adverse local tissue reactions, mortality
and radiological and clinical outcomes in small-head (28 mm) MoM
and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively. A prospective cohort study included 3341 THRs in 2714 patients.
The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were
performed in women, with a mean follow-up of 115 months (18 to 201).
There were 883 MoM and 2458 CoP bearings. Crude incidence rates
(cases/1000 person-years) were: infection 1.3 In conclusion, we found similar results for small-head MoM and
CoP bearings up to ten years post-operatively, but after ten years
MoM THRs had a higher risk of all-cause revision. Furthermore, the
presence of an adverse response to metal debris seen in the small-head
MOM group at revision is a cause for concern. Cite this article:
The use of ilioischial cage reconstruction for
pelvic discontinuity has been replaced by the Trabecular Metal (Zimmer,
Warsaw, Indiana) cup-cage technique in our institution, due to the
unsatisfactory outcome of using a cage alone in this situation.
We report the outcome of 26 pelvic discontinuities in 24 patients
(20 women and four men, mean age 65 years (44 to 84)) treated by
the cup-cage technique at a mean follow-up of 82 months (12 to 113)
and compared them with a series of 19 pelvic discontinuities in
19 patients (18 women and one man, mean age 70 years (42 to 86))
treated with a cage at a mean follow-up of 69 months (1 to 170).
The clinical and radiological outcomes as well as the survivorship
of the groups were compared. In all, four of the cup-cage group
(15%) and 13 (68%) of the cage group failed due to septic or aseptic
loosening. The seven-year survivorship was 87.2% (95% confidence interval
(CI) 71 to 103) for the cup-cage group and 49.9% (95% CI 15 to 84)
for the cage-alone group (p = 0.009). There were four major complications
in the cup-cage group and nine in the cage group. Radiological union
of the discontinuity was found in all successful cases in the cup-cage
group and three of the successful cage cases. Three hips in the
cup-cage group developed early radiological migration of the components,
which stabilised with a successful outcome. Cup-cage reconstruction is a reliable technique for treating
pelvic discontinuity in mid-term follow-up and is preferred to ilioischial
cage reconstruction. If the continuity of the bone graft at the
discontinuity site is not disrupted, early migration of the components
does not necessarily result in failure. Cite this article:
The increasing need for total hip replacement
(THR) in an ageing population will inevitably generate a larger number
of revision procedures. The difficulties encountered in dealing
with the bone deficient acetabulum are amongst the greatest challenges
in hip surgery. The failed acetabular component requires reconstruction
to restore the hip centre and improve joint biomechanics. Impaction
bone grafting is successful in achieving acetabular reconstruction
using both cemented and cementless techniques. Bone graft incorporation
restores bone stock whilst providing good component stability. We
provide a summary of the evidence and current literature regarding impaction
bone grafting using both cemented and cementless techniques in revision
THR. Cite this article:
The conventional method for reconstructing acetabular
bone loss at revision surgery includes using structural bone allograft.
The disadvantages of this technique promoted the advent of metallic
but biocompatible porous implants to fill bone defects enhancing
initial and long-term stability of the acetabular component. This
paper presents the indications, surgical technique and the outcome
of using porous metal acetabular augments for reconstructing acetabular
defects. Cite this article:
This study compared the primary stability of two commercially
available acetabular components from the same manufacturer, which
differ only in geometry; a hemispherical and a peripherally enhanced
design (peripheral self-locking (PSL)). The objective was to determine
whether altered geometry resulted in better primary stability. Acetabular components were seated with 0.8 mm to 2 mm interference
fits in reamed polyethylene bone substrate of two different densities
(0.22 g/cm3 and 0.45 g/cm3). The primary stability
of each component design was investigated by measuring the peak
failure load during uniaxial pull-out and tangential lever-out tests.Objective
Methods
Despite the worldwide usage of the cemented Contemporary
acetabular component (Stryker), no published data are available
regarding its use in patients aged <
50 years. We undertook a
mid- to long-term follow-up study, including all consecutive patients
aged
<
50 years who underwent a primary total hip replacement using
the Contemporary acetabular component with the Exeter cemented stem
between January 1999 and January 2006. There were 152 hips in 126
patients, 61 men and 65 women, mean age at surgery 37.6 years (16
to 49 yrs). One patient was lost to follow-up. Mean clinical follow-up of all implants was 7.6 years (0.9 to
12.0). All clinical questionnaire scores, including Harris hip score,
Oxford hip score and several visual analogue scales, were found
to have improved. The eight year survivorship of all acetabular
components for the endpoints revision for any reason or revision
for aseptic loosening was 94.4% (95% confidence interval (CI) 89.2
to 97.2) and 96.4% (95% CI 91.6 to 98.5), respectively. Radiological follow-up
was complete for 146 implants. The eight year survival for the endpoint
radiological loosening was 93.1% (95% CI 86.2 to 96.6). Three surviving
implants were considered radiologically loose but were asymptomatic.
The presence of acetabular osteolysis (n = 17, 11.8%) and radiolucent
lines (n = 20, 13.9%) in the 144 surviving cups indicates a need
for continued observation in the second decade of follow-up in order
to observe their influence on long-term survival. The clinical and radiological data resulting in a ten-year survival
rate >
90% in young patients support the use of the Contemporary
acetabular component in this specific patient group. Cite this article:
We assessed the orientation of the acetabular
component in 1070 primary total hip arthroplasties with hard-on-soft, small
diameter bearings, aiming to determine the size and site of the
target zone that optimises outcome. Outcome measures included complications,
dislocations, revisions and ΔOHS (the difference between the Oxford
Hip Scores pre-operatively and five years post-operatively). A wide
scatter of orientation was observed (2 This study demonstrated that with traditional technology surgeons
can only reliably achieve a target zone of ±15°. As the optimal
zone to diminish the risk of dislocation is also ±15°, surgeons
should be able to achieve this. This is the first study to demonstrate
that optimal orientation of the acetabular component improves the
functional outcome. However, the target zone is small (± 5°) and
cannot, with current technology, be consistently achieved. Cite this article:
The term developmental dysplasia of the hip (DDH)
describes a spectrum of disorders that results in abnormal development
of the hip joint. If not treated successfully in childhood, these
patients may go on to develop hip symptoms and/or secondary osteoarthritis
in adulthood. In this review we describe the altered anatomy encountered
in adults with DDH along with the management options, and the challenges
associated with hip arthroscopy, osteotomies and arthroplasty for
the treatment of DDH in young adults. Cite this article:
We compared the rate of revision for instability
after total hip replacement (THR) when lipped and non-lipped acetabular
liners were used. We hypothesised that the use of a lipped liner
in a modular uncemented acetabular component reduces the risk of
revision for instability after primary THR. Using data from the
New Zealand Joint Registry, we found that the use of a lipped liner
was associated with a significantly decreased rate of revision for instability
and for all other indications. Adjusting for the size of the femoral
head, the surgical approach and the age and gender of the patient,
this difference remained strongly significant (p <
0.001). We conclude that evidence from the New Zealand registry suggests
that the use of lipped liners with modular uncemented acetabular
components is associated with a decreased rate of revision for instability
after primary THR. Cite this article:
Noise generation has been reported with ceramic-on-ceramic
articulations in total hip replacement (THR). This study evaluated
208 consecutive Delta Motion THRs at a mean follow-up of 21 months
(12 to 35). There were 141 women and 67 men with a mean age of 59
years (22 to 84). Patients were reviewed clinically and radiologically,
and the incidence of noise was determined using a newly described
assessment method. Noise production was examined against range of
movement, ligamentous laxity, patient-reported outcome scores, activity
level and orientation of the acetabular component. There were 143
silent hips (69%), 22 (11%) with noises other than squeaking, 17
(8%) with unreproducible squeaking and 26 (13%) with reproducible
squeaking. Hips with reproducible squeaking had a greater mean range
of movement (p <
0.001) and mean ligament laxity (p = 0.004), smaller
median head size (p = 0.01) and decreased mean acetabular component
inclination (p = 0.02) and anteversion angle (p = 0.02) compared
with the other groups. There was no relationship between squeaking
and age (p = 0.13), height (p = 0.263), weight (p = 0.333), body
mass index (p = 0.643), gender (p = 0.07) or patient outcome score
(p = 0.422). There were no revisions during follow-up. Despite the
surprisingly high incidence of squeaking, all patients remain satisfied
with their hip replacement. Cite this article:
The aim of this prospective randomised study
was to compare the clinical and radiological results of a cemented
all-polyethylene Ultima acetabular component with those of a cementless
porous-coated acetabular component (PFC) following total hip replacement
(THR). A total of 287 patients received either a polyethylene acetabular
component (group A) or a cobalt–chromium porous-coated component
(group B) with an identical cemented femoral component and 28 mm
cobalt-chromium head, thus making it the largest study of its type.
Patients were evaluated radiologically and clinically using the
Harris hip score (HHS). Group A comprised 183 patients (73 male,
110 female) with a mean age of
71.3 years (55 to 89). Group B comprised 104 patients (48 male,
56 female) with a mean age of 69.8 years (56 to 89). A total of
16 patients (13 in Group A, three in Group B) did not have post-operative
data for analysis. The mean follow-up in group A was 7.52 years
(0.4 to 15.0) and in Group B 7.87 years (0.5 to 14.0). At final follow-up the mean HHS was similar between groups A
and B (74.5 (25 to 100) and 78.0 (37 to 100), respectively; p =
0.068). The total number of revisions for any cause was 28, 17 of
which were in group A and 11 in group B. The ten-year survivorship
was 86.8% (95% confidence interval (CI) 78.4 to 92.1) and 89.2%
(95% CI 78.3 to 94.8) for groups A and B, respectively (log-rank
p-value = 0.938). A total of 20 cemented and two cementless acetabular
components had evidence of acetabular radiolucencies or acetabular
component migration at last follow-up (p = 0.001). These results indicate that patients with a cemented all-polyethylene
and cementless porous-coated polyethylene lined acetabular component
have similar long-term clinical outcomes.
There is great variability in acetabular component
orientation following hip replacement. The aims of this study were
to compare the component orientation at impaction with the orientation
measured on post-operative radiographs and identify factors that
influence the difference between the two. A total of 67 hip replacements
(52 total hip replacements and 15 hip resurfacings) were prospectively
studied. Intra-operatively, the orientation of the acetabular component
after impaction relative to the operating table was measured using
a validated stereo-photogrammetry protocol. Post-operatively, the
radiographic orientation was measured; the mean inclination/anteversion
was 43° (. sd. 6°)/ 19° (. sd. 7°). A simulated radiographic
orientation was calculated based on how the orientation would have
appeared had an on-table radiograph been taken intra-operatively.
The mean difference between radiographic and intra-operative inclination/anteversion
was 5° (. sd . 5°)/ -8° (. sd. 8°). The mean difference between
simulated radiographic and intra-operative inclination/anteversion,
which quantifies the effect of the different way acetabular orientation
is measured, was 3°/-6° (. sd. 2°). The mean difference between
radiographic and simulated radiographic orientation inclination/anteversion,
which is a manifestation of the change in pelvic position between
component impaction and radiograph, was 1°/-2° (. sd . 7°). This study demonstrated that in order to achieve a specific radiographic
orientation target, surgeons should
The purpose of this study was to compare the
amount of acetabular bone removed during hip resurfacing (HR) and cementless
total hip replacement (THR), after controlling for the diameter
of the patient’s native femoral head. Based on a power analysis,
64 consecutive patients (68 hips) undergoing HR or THR were prospectively
enrolled in the study. The following data were recorded intra-operatively:
the diameter of the native femoral head, the largest reamer used,
the final size of the acetabular component, the size of the prosthetic
femoral head and whether a decision was made to increase the size
of the acetabular component in order to accommodate a larger prosthetic femoral
head. Results were compared using two-sided, independent samples
Student’s
Hip resurfacing is a bone-conserving procedure with respect to proximal femoral resection, but there is debate in the literature as to whether the same holds true for the acetabulum. We have investigated whether the Birmingham hip resurfacing conserves acetabular bone. Between 1998 and 2005, 500 Birmingham hip resurfacings were performed by two surgeons. Between 1996 and 2005 they undertook 700 primary hip replacements, with an uncemented acetabular component. These patients formed the clinical material to compare acetabular component sizing. The Birmingham hip resurfacing group comprised 350 hips in men and 150 hips in women. The uncemented total hip replacement group comprised 236 hips in men and 464 hips in women. Age- and gender-matched analysis of a cohort of patients for the sizes of the acetabular components required for the two types of replacement was also undertaken. Additionally, an analysis of the sizes of the components used by each surgeon was performed. For age-matched women, the mean outside diameter of the Birmingham hip resurfacing acetabular components was 2.03 mm less than that of the acetabular components in the uncemented total hip replacements (p <
0.0001). In similarly matched men there was no significant difference (p = 0.77). A significant difference was also found between the size of acetabular components used by the two surgeons for Birmingham hip resurfacing for both men (p = 0.0015) and women (p = 0.001). In contrast, no significant difference was found between the size of acetabular components used by the two surgeons for uncemented total hip replacement in either men or women (p = 0.06 and p = 0.14, respectively). This suggests that variations in acetabular preparation also influence acetabular component size in hip resurfacing.
We report the results of the revision of 123 acetabular components for aseptic loosening treated by impaction bone grafting using frozen, morsellised, irradiated femoral heads and cemented sockets. This is the first large series using this technique to be reported. A survivorship of 88% with revision as the end-point after a mean of five years is comparable with that of other series.
This study compared component wear rates and pre-revision blood metal ions levels in two groups of failed metal-on-metal hip arthroplasties: hip resurfacing and modular total hip replacement (THR). There was no significant difference in the median rate of linear wear between the groups for both acetabular (p = 0.4633) and femoral (p = 0.0872) components. There was also no significant difference in the median linear wear rates when failed hip resurfacing and modular THR hips of the same type (ASR and Birmingham hip resurfacing (BHR)) were compared. Unlike other studies of well-functioning hips, there was no significant difference in pre-revision blood metal ion levels between hip resurfacing and modular THR. Edge loading was common in both groups, but more common in the resurfacing group (67%) than in the modular group (57%). However, this was not significant (p = 0.3479). We attribute this difference to retention of the neck in resurfacing of the hip, leading to impingement-type edge loading. This was supported by visual evidence of impingement on the femur. These findings show that failed metal-on-metal hip resurfacing and modular THRs have similar component wear rates and are both associated with raised pre-revision blood levels of metal ions.
It is accepted that resurfacing hip replacement
preserves the bone mineral density (BMD) of the femur better than total
hip replacement (THR). However, no studies have investigated any
possible difference on the acetabular side. Between April 2007 and March 2009, 39 patients were randomised
into two groups to receive either a resurfacing or a THR and were
followed for two years. One patient’s resurfacing subsequently failed,
leaving 19 patients in each group. Resurfaced replacements maintained proximal femoral BMD and,
compared with THR, had an increased bone mineral density in Gruen
zones 2, 3, 6, and particularly zone 7, with a gain of 7.5% (95%
confidence interval (CI) 2.6 to 12.5) compared with a loss of 14.6%
(95% CI 7.6 to 21.6). Resurfacing replacements maintained the BMD
of the medial femoral neck and increased that in the lateral zones
between 12.8% (95% CI 4.3 to 21.4) and 25.9% (95% CI 7.1 to 44.6). On the acetabular side, BMD was similar in every zone at each
point in time. The mean BMD of all acetabular regions in the resurfaced
group was reduced to 96.2% (95% CI 93.7 to 98.6) and for the total
hip replacement group to 97.6% (95% CI 93.7 to 101.5) (p = 0.4863).
A mean total loss of 3.7% (95% CI 1.0 to 6.5) and 4.9% (95% CI 0.8
to 9.0) of BMD was found above the acetabular component in W1 and
10.2% (95% CI 0.9 to 19.4) and 9.1% (95% CI 3.8 to 14.4) medial
to the implant in W2 for resurfaced replacements and THRs respectively.
Resurfacing resulted in a mean loss of BMD of 6.7% (95% CI 0.7 to
12.7) in W3 but the BMD inferior to the acetabular component was
maintained in both groups. These results suggest that the ability of a resurfacing hip replacement
to preserve BMD only applies to the femoral side.
The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components. A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis. Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups. Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation.
Orientation of the acetabular component influences
wear, range of movement and the incidence of dislocation after total
hip replacement (THR). During surgery, such orientation is often
referenced to the anterior pelvic plane (APP), but APP inclination
relative to the coronal plane (pelvic tilt) varies substantially
between individuals. In contrast, the change in pelvic tilt from
supine to standing (dPT) is small for nearly all individuals. Therefore,
in THR performed with the patient supine and the patient’s coronal
plane parallel to the operating table, we propose that freehand placement
of the acetabular component placement is reliable and reflects standing
(functional) cup position. We examined this hypothesis in 56 hips
in 56 patients (19 men) with a mean age of 61 years (29 to 80) using
three-dimensional CT pelvic reconstructions and standing lateral
pelvic radiographs. We found a low variability of acetabular component
placement, with 46 implants (82%) placed within a combined range
of 30° to 50° inclination and 5° to 25° anteversion. Changing from
the supine to the standing position (analysed in 47 patients) was associated
with an anteversion change <
10° in 45 patients (96%). dPT was
<
10° in 41 patients (87%). In conclusion, supine THR appears
to provide reliable freehand acetabular component placement. In
most patients a small reclination of the pelvis going from supine
to standing causes a small increase in anteversion of the acetabular component Cite this article:
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 range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard acetabular component position (abduction 45°/anteversion 15°). With respect to the registration of the plane defined by the TAL and the posterior labrum, there was moderate interobserver agreement (r = 0.64, p <
0.001) and intra-observer reproducibility (r = 0.73, p <
0.001). The mean acetabular component orientation achieved was abduction of 41° (32° to 51°) and anteversion of 18° (−1° to 36°). With respect to the Lewinnek safe zone (abduction 40° ±10°, anteversion 15° ±10°), 35 of the 39 acetabular components were within this zone. However, there was no improvement in the range of movement (p = 0.94) and no significant difference in impingement (p = 0.085). Alignment of the acetabular component with the TAL and the posterior labrum might reduce the variability of acetabular component placement in total hip replacement. However, there is only a moderate interobserver agreement and intra-observer reliability in the alignment of the acetabular component using the TAL and the posterior labrum. No reduction in impingement was found when the acetabular component was aligned with the TAL and the posterior labrum, compared with a standard acetabular component position.
We reviewed the results at nine to 13 years of 125 total hip replacements in 113 patients using the monoblock uncemented Morscher press-fit acetabular component. The mean age at the time of operation was 56.9 years (36 to 74). The mean clinical follow-up was 11 years (9.7 to 13.5) and the mean radiological follow-up was 9.4 years (7.7 to 13.1). Three hips were revised, one immediately for instability, one for excessive wear and one for deep infection. No revisions were required for aseptic loosening. A total of eight hips (7.0%) had osteolytic lesions greater than 1 cm, in four around the acetabular component (3.5%). One required bone grafting behind a well-fixed implant. The mean wear rate was 0.11 mm/year (0.06 to 0.78) and was significantly higher in components with a steeper abduction angle. Kaplan-Meier survival curves at 13 years showed survival of 96.8% (95% confidence interval 90.2 to 99.0) for revision for any cause and of 95.7% (95% confidence interval 88.6 to 98.4) for any acetabular re-operation.
We evaluated the long-term results of 116 total hip replacements with a superolateral shelfplasty in 102 patients with osteoarthritis secondary to developmental dysplasia of the hip. After a mean follow-up of 19.5 years (11.5 to 26.0), 14 acetabular components (12%) had been revised. The cumulative survival at 20 years was 78%, with revision for loosening of the acetabular component as the end-point. All grafts were well integrated and showed remodelling. In six grafts some resorption had occurred under the heads of the screws where the graft was not supporting the socket. Apart from these 14 revisions, seven acetabular components had possible radiological signs of loosening at a mean follow-up of 14.5 years, one had signs of probable loosening, and five had signs of definite loosening. These results indicate that this technique of bone grafting for acetabular reconstruction in hip dysplasia is a durable solution for cemented acetabular components.
The presence of pseudotumours, which are soft-tissue masses relating to the hip, after metal-on-metal hip resurfacing arthroplasty has been associated with elevated levels of metal ions in serum, suggesting that pseudotumours occur when there is increased wear. We aimed to quantify the wear in vivo of implants revised for pseudotumours (eight) and of a control group of implants (22) revised for other reasons of failure. We found that the implant group with pseudotumours had a significantly higher rate of median linear wear of the femoral component at 8.1 μm/year (2.75 to 25.4) than the 1.79 μm/year (0.82 to 4.15; p = 0.002) of the non-pseudotumour group. For the acetabular component a significantly higher rate of median linear wear of 7.36 μm/year (1.61 to 24.9) was observed in the pseudotumour group compared with 1.28 μm/year (0.81 to 3.33, p = 0.001) in the other group. Wear of the acetabular component in the pseudotumour group always involved the edge of the implant, indicating that edge-loading had occurred. Our findings are the first direct evidence that pseudotumour is associated with increased wear at the metal-on-metal articulation. Furthermore, edge-loading with the loss of fluid-film lubrication may be an important mechanism of generation of wear in patients with a pseudotumour.
Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p <
0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50° (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% ( The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years.
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/m2) and obese (BMI ≥ 30 kg/m2). 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 range of movement, but overall satisfaction with surgery was comparable with that of the obese patients. Radiological analysis of the acetabular and femoral components showed no significant differences with regard to radiolucent lines, osteolysis, ingrowth of the femoral component, the acetabular inclination angle or alignment of the femoral component. Our results suggest that the survival of cementless THR is not adversely affected by obesity. Obese patients can therefore be counselled that despite a lower clinical score, they should expect to be satisfied with the result of their THR with a mid-term survival rate equivalent to that of non-obese patients.
We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason as the endpoint was 75% at 20 years (95% confidence interval (CI) 62 to 88) when 16 hips were at risk. Excluding two revisions for septic loosening at three and six years, the survivorship at 20 years was 79% (95% CI 67 to 93). With further exclusions of one revision of a well-fixed acetabular component after 12 years during a femoral revision and two after 17 years for wear of the acetabular component, the survivorship for aseptic loosening was 87% at 20 years (95% CI 76 to 97). At the final review 14 of the 16 surviving hips had radiographs available. There was one additional case of radiological loosening and four acetabular reconstructions showed progressive radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.5 cm to 1 cm in diameter) and a cemented acetabular component remains a reliable technique for reconstruction, even when assessed at more than 20 years after surgery.
The rate and mode of early failure in 463 Birmingham hip resurfacings in a two-centre, multisurgeon series were examined. Of the 463 patients two have died and three were lost to follow-up. The mean radiological and clinical follow-up was for 43 months (6 to 90). We have revised 13 resurfacings (2.8%) including seven for pain, three for fracture, two for dislocation and another for sepsis. Of these, nine had macroscopic and histological evidence of metallosis. The survival at five years was 95.8% (95% confidence interval (CI) 94.1 to 96.8) for revision for all causes and 96.9% (95% CI 95.5 to 98.3) for metallosis. The rate of metallosis related revision was 3.1% at five years. Risk factors for metallosis were female gender, a small femoral component, a high abduction angle and obesity. We do not advocate the use of the Birmingham Hip resurfacing procedure in patients with these risk factors.
Infection of a total hip replacement (THR) requires component removal and thorough local debridement. Usually, long-term antibiotic treatment in conjunction with a two-stage revision is required. This may take several months. One-stage revision using antibiotic-loaded cement has not gained widespread use, although the clinical and economic advantages are obvious. Allograft bone may be impregnated with high levels of antibiotics, and in revision of infected THR, act as a carrier providing a sustained high local concentration. We performed 37 one-stage revision of infected THRs, without the use of cement. There were three hips which required further revision because of recurrent infection, the remaining 34 hips (92%) stayed free from infection and stable at a mean follow-up of 4.4 years (2 to 8). No adverse effects were identified. Incorporation of bone graft was comparable with unimpregnated grafts. Antibiotic-impregnated allograft bone may enable reconstruction of bone stock, insertion of an uncemented implant and control of infection in a single operation in revision THR for infection.
Early failure associated with adverse reactions to metal debris is an emerging problem after hip resurfacing but the exact mechanism is unclear. We analysed our entire series of 660 metal-on-metal resurfacings (Articular Surface Replacement (ASR) and Birmingham Hip Resurfacing (BHR)) and large-bearing ASR total hip replacements, to establish associations with metal debris-related failures. Clinical and radiological outcomes, metal ion levels, explant studies and lymphocyte transformation tests were performed. A total of 17 patients (3.4%) were identified (all ASR bearings) with adverse reactions to metal debris, for which revision was required. This group had significantly smaller components, significantly higher acetabular component anteversion, and significantly higher whole concentrations of blood and joint chromium and cobalt ions than asymptomatic patients did (all p <
0.001). Post-revision lymphocyte transformation tests on this group showed no reactivity to chromium or cobalt ions. Explants from these revisions had greater surface wear than retrievals for uncomplicated fractures. The absence of adverse reactions to metal debris in patients with well-positioned implants usually implies high component wear. Surgeons must consider implant design, expected component size and acetabular component positioning in order to reduce early failures when performing large-bearing metal-on-metal hip resurfacing and replacement.
The National Institute for Clinical Excellence (NICE) published the guidelines on the selection of prostheses for primary hip replacement in 2000. They supported the use of cemented hip prostheses to the exclusion of uncemented and hybrid implants. The information from the Trent (and Wales) Regional Arthroplasty Study has been examined to identify retrospectively the types of hip prostheses used between 1990 and 2005, and to assess the impact that the guidelines have had on orthopaedic practice. The results show that the publication of the NICE guidelines has had little impact on clinical practice, with the use of uncemented prostheses increasing from 6.7% (137) in 2001 to 19.2% (632) in 2005. The use of hybrid prostheses has more than doubled from 8.8% (181) to 22% (722) of all hips implanted in the same period. The recommendations made by NICE are not being followed, which calls into question their value.
Deficiencies of acetabular bone stock at revision hip replacement were reconstructed with two different types of allograft using impaction bone grafting and a Burch-Schneider reinforcement ring. We compared a standard frozen non-irradiated bone bank allograft (group A) with a freeze-dried irradiated bone allograft, vitalised with autologous marrow (group B). We studied 78 patients (79 hips), of whom 87% (69 hips) had type III acetabular defects according to the American Academy of Orthopaedic Surgeons classification at a mean of 31.4 months (14 to 51) after surgery. At the latest follow-up, the mean Harris hip score was 69.9 points (13.5 to 97.1) in group A and 71.0 points (11.5 to 96.5) in group B. Each hip showed evidence of trabeculation and incorporation of the allograft with no acetabular loosening. These results suggest that the use of an acetabular reinforcement ring and a living composite of sterile allograft and autologous marrow appears to be a method of reconstructing acetabular deficiencies which gives comparable results to current forms of treatment.
We have reviewed a group of patients with iliopsoas impingement after total hip replacement with radiological evidence of a well-fixed malpositioned or oversized acetabular component. A consecutive series of 29 patients (30 hips) was assessed. All had undergone a trial of conservative management with no improvement in their symptoms. Eight patients (eight hips) preferred continued conservative management (group 1), and 22 hips had either an iliopsoas tenotomy (group 2) or revision of the acetabular component and debridement of the tendon (group 3), based on clinical and radiological findings. Patients were followed clinically for at least two years, and 19 of the 22 patients (86.4%) who had surgery were contacted by phone at a mean of 7.8 years (5 to 9) post-operatively. Conservative management failed in all eight hips. At the final follow-up, operative treatment resulted in relief of pain in 18 of 22 hips (81.8%), with one hip in group 2 and three in group 3 with continuing symptoms. The Harris Hip Score was significantly better in the combined groups 2 and 3 than in group 1. There was a significant rate of complications in group 3. This group initially had better functional scores, but at final follow-up these were no different from those in group 2. Tenotomy of the iliopsoas and revision of the acetabular component are both successful surgical options. Iliopsoas tenotomy provided the same functional results as revision of the acetabular component and avoided the risks of the latter procedure.
We retrospectively reviewed, ten years after surgery, 100 consecutive total hip replacements in which the Duraloc 300 cup had been used. Post-operative radiographs were analysed for placement of the cup and interface gaps and follow-up radiographs for lucent lines, osteolysis, wear and migration. All the components were found to be stable with no evidence of loosening. The mean rate of wear was 0.12 mm/year. Three hips developed acetabular osteolysis at the level of the apex hole. Two have successfully undergone bone grafting without removal of the implants and one patient is awaiting surgery. The Duraloc 300 cup has a survival of 100% at ten years with no aseptic loosening and a low incidence of pelvic osteolysis.
Bisphosphonates reduce peri-prosthetic bone loss in the short term after total hip replacement but the mid- and longer term effects are not known. The aims of this randomised trial were to examine the effect of a single dose of 90 mg of pamidronate on the clinical and radiological outcome and peri-prosthetic bone mineral density in 50 patients (56 hips) over a five-year period, following total hip replacement. At five years, 37 patients (42 hips) returned for assessment. The Harris hip scores were similar in the pamidronate and placebo groups throughout the study. Also at five years, four patients, two from each group had osteolytic lesions on plain radiography. These were located around the acetabular component in three patients and in the femoral calcar in one. The femoral and acetabular peri-prosthetic bone mineral density in the pamidronate group and the control group was similar at five years. Pamidronate given as a single post-operative dose does not appear to influence the clinical outcome or prevent the development of osteolytic lesions at five years after total hip replacement.
We reviewed the clinical and radiological results of 131 patients who underwent acetabular revision for aseptic loosening with impacted bone allograft and a cemented acetabular component. The mean follow-up was 51.7 months (24 to 156). The mean post-operative Merle D’Aubigné and Postel scores were 5.7 points (4 to 6) for pain, 5.2 (3 to 6) for gait and 4.5 (2 to 6) for mobility. Radiological evaluation revealed migration greater than 5 mm in four acetabular components. Radiological failure matched clinical failure. Asymptomatic radiolucent lines were observed in 31 of 426 areas assessed (7%). Further revision was required in six patients (4.5%), this was due to infection in three and mechanical failure in three. The survival rate for the reconstruction was 95.8% (95% confidence interval 92.3 to 99.1) overall, and 98%, excluding revision due to sepsis. Our study, from an independent centre, has reproduced the results of the originators of the method.
We investigated 219 revisions of total hip replacement (THR) in 211 patients using a collarless double-taper cemented femoral component. The mean age of the patients was 72 years (30 to 90). The 137 long and 82 standard length stems were analysed separately. The mean follow-up was six years (2 to 18), and no patient was lost to follow-up. Survival of the long stems to re-revision for aseptic loosening at nine years was 98% (95% confidence interval (CI) 94 to 100), and for the standard stems was 93% (95% CI 85 to 100). At five years, one long stem was definitely loose radiologically and one standard stem was probably loose. Pre-operative femoral bone deficiency did not influence the results for the long stems, and corrective femoral osteotomy was avoided, as were significant subsidence, major stress shielding and persistent thigh pain. Because of these reliable results, cemented long collarless double-taper femoral components are recommended for routine revision THR in older patients.
Our aim was to determine if the height of the cup, lateralisation or the abduction angle correlated with functional outcome or survivorship in revision total hip replacement in patients with a previous diagnosis of developmental dysplasia of the hip. A retrospective investigation of 51 patients (63 hips) who had undergone revision total hip replacement was performed. The mean duration of follow-up was 119 months. Forty-one patients (52 hips) were available for both determination of functional outcome and survivorship analysis. Ten patients (11 hips) were only available for survivorship analysis. The height of the cup was found to have a statistically significant correlation with functional outcome and a high hip centre correlated with a worse outcome score. Patients with a hip centre of less than 3.5 cm above the anatomical level had a statistically better survivorship of the cup than those with centres higher than this. Restoration of the height of the centre of the hip to as near the anatomical position as possible improved functional outcome and survivorship of the cup.
We systematically reviewed the peer-reviewed literature to relate the survival of hybrid metal-on-metal hip resurfacing arthroplasty devices to a National Institute of Clinical Excellence (NICE) benchmark for choosing a primary total hip replacement, which is a survival rate of 90% at a follow-up of ten years. A total of 29 articles (10 621 resurfaced hips) met the inclusion criteria. The mean follow-up ranged from 0.6 to 10.5 years and the survival of the implant ranged from 84% to 100%. Of the 10 621 hips, 370 were revised (3.5%), with aseptic loosening as the most frequent mode of failure. None of the hip resurfacing arthroplasty implants used to date met the full ten-year NICE benchmark of survival. A total of 13 studies showed satisfactory survival compared with the three-year NICE benchmark.
There have been no large comparative studies of the blood levels of metal ions after implantation of commercially available hip resurfacing devices which have taken into account the effects of femoral size and inclination and anteversion of the acetabular component. We present the results in 90 patients with unilateral articular surface replacement (ASR) hip resurfacings (mean time to blood sampling 26 months) and 70 patients with unilateral Birmingham Hip Resurfacing (BHR) implants (mean time 47 months). The whole blood and serum chromium (Cr) and cobalt (Co) concentrations were inversely related to the size of the femoral component in both groups (p <
0.05). Cr and Co were more strongly influenced by the position of the acetabular component in the case of the ASR, with an increase in metal ions observed at inclinations >
45° and anteversion angles of <
10° and >
20°. These levels were only increased in the BHR group when the acetabular component was implanted with an inclination >
55°. A significant relationship was identified between the anteversion of the BHR acetabular component and the levels of Cr and Co (p <
0.05 for Co), with an increase observed at anteversion angles <
10° and >
20°. The median whole blood and serum Cr concentrations of the male ASR patients were significantly lower than those of the BHR men (p <
0.001). This indicates that reduced diametral clearance may equate to a reduction in metal ion concentrations in larger joints with satisfactory orientation of the acetabular component.
In 12 patients, we measured the oxygen concentration in the femoral head-neck junction during hip resurfacing through the anterolateral approach. This was compared with previous measurements made for the posterior approach. For the anterolateral approach, the oxygen concentration was found to be highly dependent upon the position of the leg, which was adjusted during surgery to provide exposure to the acetabulum and femoral head. Gross external rotation of the hip gave a significant decrease in oxygenation of the femoral head. Straightening the limb led to recovery in oxygen concentration, indicating that the blood supply was maintained. The oxygen concentration at the end of the procedure was not significantly different from that at the start. The anterolateral approach appears to produce less disruption to the blood flow in the femoral head-neck junction than the posterior approach for patients undergoing hip resurfacing. This may be reflected subsequently in a lower incidence of fracture of the femoral neck and avascular necrosis.
We performed 52 total hip replacements in 52 patients using a cementless acetabular component combined with a circumferential osteotomy of the medial acetabular wall for the late sequelae of childhood septic arthritis of the hip. The mean age of the patients at operation was 44.5 years (22 to 66) and the mean follow-up was 7.8 years (5 to 11.8). The mean improvement in the Harris Hip Score was 29.6 points (19 to 51) at final follow-up. The mean cover of the acetabular component was 98.5% (87.8% to 100%). The medial acetabular wall was preserved with a mean thickness of 8.3 mm (1.7 to 17.4) and the mean length of abductor lever arm increased from 43.4 mm (19.1 to 62) to 54.2 mm (36.5 to 68.6). One acetabular component was revised for loosening and osteolysis 4.5 years postoperatively, and one had radiolucent lines in all acetabular zones at final review. Kaplan-Meier survival was 94.2% (95% confidence interval 85.8% to 100%) at 7.3 years, with revision or radiological loosening as an end-point when two hips were at risk. A cementless acetabular component combined with circumferential medial acetabular wall osteotomy provides favourable results for acetabular reconstruction in patients who present with late sequelae of childhood septic hip arthritis.
In a prospective randomised clinical study acetabular components were implanted either freehand (n = 30) or using CT-based (n = 30) or imageless navigation (n = 30). The position of the component was determined post-operatively on CT scans of the pelvis. Following conventional freehand placement of the acetabular component, only 14 of the 30 were within the safe zone as defined by Lewinnek et al (40° inclination Imageless navigation proved as reliable as that using CT in positioning the acetabular component.
We performed 114 consecutive primary total hip arthroplasties with a cementless expansion acetabular component in 101 patients for advanced osteonecrosis of the femoral head. The mean age of the patients at surgery was 51 years (36 to 62) and the mean length of follow-up was 110 months (84 to 129). The mean pre-operative Harris hip score of 47 points improved to 93 points at final follow-up. The polyethylene liner was exchanged in two hips during this period and one broken acetabular component was revised. The mean linear wear rate of polyethylene was 0.07 mm/year and peri-acetabular osteolysis was seen in two hips (1.9%). Kaplan-Meier analysis indicated that the survival of the acetabular component without revision was 97.8% (95% confidence interval 0.956 to 1.000) at ten years. Our study has shown that the results of THA with a cementless expansion acetabular component and an alumina-polyethylene bearing surface are good.
