Purpose: Fracture of alumina implants is a rare cause of total hip arthroplasty (THA) failure. Over the last twenty years, improvement in the design of ceramic implants has helped reduce this risk. We observed five cases of alumina
Uncemented hip implants commonly have porous coated surfaces that enhance the mechanical interlock with bone, encourage bone ingrowth and promote the formation of a stable interface between prosthesis and bone. However, the presence of tissue, either fibrous or with parts of osseous tissue, at the interface between the implant and the bone has been commonly observed after a few years in vivo. The exact mechanisms that govern the type of tissues formed at the interface are not fully understood and several theories have been proposed. This study aims to employ finite element analysis (FEA) to simulate tissue formation and differentiation around the AML (DePuy, Warsaw, USA) femoral implant by employing a tissue differentiation algorithm based on a mechanoregulatory hypothesis of fracture healing. FE models of the femur were generated using computer tomography (CT) scans. The AML prosthesis was then implanted into the bone and a granulation tissue layer of 0.75mm was created around the implant. The mechanoregulatory hypothesis of Carter et al (J.Orthop, 1988) originally developed to explain fracture healing was used with selected modifications, most notably the addition of a quantitative module to the otherwise qualitative algorithm. The tendency of ossification in the original hypothesis was modified to simulate tissue differentiation to bone, cartilage or fibrous tissue. Normal walking and stair climbing loads were used for a specified number of cycles reflecting typical patient activity post surgery. The transformation of granulation tissue to one of the three simulated tissue types was evident as the iterations progressed. The majority of the tissue type formed initially was cartilage and bone (~40% each), and occupied the mid to distal regions of the implant respectively. After tissue stabilisation, the prominent tissue type was bone (65%), occupying most of the mid-distal regions with a significant decline in cartilage tissue formed. This has been shown in clinical retrieval studies with the same implant, where maximum bone ingrowth is in the mid-distal regions of the implant, directly corresponding to the region where there is minimal micromotion. This would be the case with a diaphyseal fixation, which most AML prostheses employ for stability. Fibrous tissue formation was limited to the proximal-medial regions (~10%), with the remainder of the proximal regions filled with cartilage tissue. In addition, predicted bone formation was along the lines of the more stable cartilage tissue as opposed to directly replacing fibrous tissue. The formation of bone would require repeated periods of minimal micromotion and stress at the interface tissue; this was facilitated by the presence of cartilage tissue around the mid regions of the implant. The micromotion and interface stresses in the proximal regions of the implant were too high to encourage bone ingrowth, resulting in the presence of tissue that remained fibrous throughout the process. The FE model, employing a very simple tissue differentiation hypothesis and algorithm was able to predict the formation of different tissues at the interface. Initial bone formation was rapid, occupying the distal regions of the implant, and then gradually occupying a larger portion of the mid-regions around the implant. The proximal regions were largely occupied by a combination of fibrous and cartilage tissue. Overall, the presence of bone and cartilage tissue accounted for nearly 85% of the tissue formed which would suggest a very stable interface as predicted by the Carter’s hypothesis.
Introduction. Frame HI is the #Days for device removal/cm. IM Nail HI is less relevant (31–45 D/cm). Albizzia HI was 33 D/cm (1991–2003). Patients felt fine approximately 1M after end of lengthening (EoL), resuming normal life and sports. This sometimes resulted in
Introduction. Approximately 2,000 Skeletal transcutaneous osseointegration (STOI) procedures have been performed worldwide as of 2020, more than half of which have been performed by the Osseointegration Group of Australia using a press-fit technique with either ILP or OPL implant designs. Despite the consistently demonstrated clinical benefits, concerns regarding potential complications following STOI have slowed its widespread adoption. As more patients are followed for a longer period of time, longitudinal studies have confirmed complication rates are very acceptable, similar to those of total ankle and total elbow replacements. One of the major risk category is implant removal. The primary goal of this study was to investigate the complications and technical issues associated with transtibial osseointegration implant removal due to any cause. The focus here will be on the press-fit ILP and OPL implants, including the indications for removal and patient outcomes following removal. Materials & Methods. A review of our osseointegration registry between November 2010 and March 2022 was performed. Inclusion criteria were patients who have undergone removal of a transtibial osseointegration implant due to any cause. Selected patients either had a follow-up of at least two years or had their index osseointegration surgery at least two years prior to when the study was performed. Patients who have had osseointegration at other anatomic levels, and patients who underwent simultaneous total knee replacement with transtibial osseointegration were excluded from the registry search. Results. There were a total of 148 transtibial osseointegration procedures performed during the study period, with 97 (65.5%) performed in males and 51 (34.5%) performed in females. The average age at first stage osseointegration procedure is 50.4 years (range 16.8–87.9, SD 14.1). In the study cohort of 22 cases requiring implant removals, 12 (54.5%) were male and 10 (45.5%) were female. The average age at first stage osseointegration procedure in this cohort is 51.3 (range 37.4–82.6, SD 10.7) and average BMI 30.3 (range 21.9–40.9, SD 5.8). Although men comprised the majority of removals, women had a greater relative risk (Fisher exact test p=0.032). The average duration from time of STOI to removal was 2.6 years (range 0.1–6.8, SD 1.9) within this 11.5 year follow-up period. The most frequent indication was infection (54.6%, n=12) followed equally by pain (13.6%, n=3), aseptic loosening (13.6%, n=3) and
The Exeter. ™. V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing
Introduction. Osseointegration is a potential treatment option for transfemoral amputees experiencing socket related problems. Till this date, there is little data assessing the feasibility and advantages of osseointegration in individuals with transtibial amputations. Materials and Methods. We prospectively followed 91 patients undergoing transtibial osseointegration from 2014–2018 who either 1) reported pain or mobility dissatisfaction with socket prosthesis; 2) had an intact limb with incapacitating pain, complex deformity, or profound distal weakness or 3) were recent amputees preferring osseointegration. Adverse events were monitored including infection, periprosthetic
Aims. The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing
The benefit of dual mobility cup (DMC) for primary total hip arthroplasties (THA) is still controversial. This study aimed to compare 1) the complications rate, 2) the revisions rate, 3) the survival rate after monobloc DMC compared to large femoral heads (LFH) in primary THA. Between 2010 and 2019, 2,075 primary THA using cementless DMC or LFH were included. Indications for DMC were patients older than 70 years old or with high risk of dislocation. Every other patient received a LFH. Exclusion criteria were cemented
Periprosthetic femur fracture (PPF) are heterogeneous, complex, and thought to be increasingly prevalent. The aims were to evaluate PPF prevalence, casemix, management, and outcomes. This nationwide study included all PPF patients aged >50 years from 16 Scottish hospitals in 2019. Variables included: demographics;
Traditional socket prosthesis (TSP) rehabilitation for amputees is associated with substantial dissatisfaction due to poor mobility and pain from soft tissue squeezing. Osseointegration (OI), eliminates skin compression and prosthesis fit issues, providing superior mobility and quality of life (QOL) for most amputees. The potential for OI to benefit patients with exceptionally poor mobility is understudied. To address this knowledge gap, this project investigated the mobility and QOL changes. A retrospective review was performed to identify transfemoral amputees who presented with wheelchair-bound mobility (K0) and had at least five years of post-osseointegration follow-up. Outcome measures included changes in mobility (K-level, daily prosthesis wear hours, Timed Up and Go (TUG), 6 minute walk test (6MWT)) and QOL (Questionnaire for persons with a Transfemoral Amputation (QTFA); Short Form Health Survey 36 (SF36). Adverse events recorded included debridement for infection,
Introduction. Osseointegration has emerged as a promising alternative to rehabilitating with a traditional socket mounted prosthesis. Advantages have been reported to include improved functional mobility, better osseoperception, improved comfort, reduced pain, better biomechanical alignment and better gait, which all lead to a less restricted lifestyle and significantly improved quality of life. A major concern of the Osseointegrated approach lies in the risk of infections occurring from the permanent transcutaneous opening often referred to as the stoma. Several systematic reviews have indicated that the occurrence of minor infections can be quite common, serious complications are reported to be rare. In addition to commonly anticipated complications including fractures, surgical debridements or revisions, we have identified several significant events in which a patient may require to be readmitted and go through additional surgery. The objective of this study is to examine the rate of occurrence and reports on the best management practices of serious complications across a multi-centre review of more than 1000 osseointegration surgeries. Materials & Methods. A detailed analysis has been performed on all osseointegration surgeries performed by the Osseointegration Group of Australia and it's affiliates between since 2010. The majority of surgeries took place in Australia, the United States, the Middle East as well as in Europe. All events leading to a re-admission and subsequent re-operation have been identified through hospital operation records and pooled together for meta-analysis. Events identified include: revision of
Introduction. Advantages of osseointegration have been reported to include improved functional mobility, better osseoperception, improved comfort, reduced pain, better biomechanical alignment and gait, which all lead to a less restricted lifestyle and significantly improved quality of life. A major concern of the Osseointegrated approach lies in the risk of infections occurring from the permanent transcutaneous opening often referred to as the stoma. Materials and Methods. Detailed analysis has been performed on all osseointegration surgeries performed by the Osseointegration Group of Australia and it's affiliates since 2010. All events leading to a re-admission and subsequent re-operation have been identified through hospital operation records and pooled together for meta-analysis. Events identified include: revision of
The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection. We performed an analysis of the Prevision modular hip stem using the manufacturer’s vigilance database and investigated different mechanical failure patterns of the hip stem from January 2004 to December 2022.Aims
Methods
Introduction. Mechanical or corrosive failure of total knee arthroplasties (TKAs) is difficult to diagnose with current laboratory and radiographic analyses. As such, the goal of this study was to determine the mean blood concentration of cobalt, chromium, and titanium in a series of revision TKAs with mechanical implant failure and evaluate whether they facilitated identification of the underlying TKA failure mechanism. Methods. Serum cobalt, chromium, and titanium levels and synovial fluid characteristics were evaluated in 12 patients (13 aseptic revision TKAs) who underwent revision TKA between 2000 and 2020 at a single academic institution for mechanical implant failure or corrosion. Seventy-five percent were re-revisions of previously revised TKAs. Mean time to revision was 6 years. Modular metallic junctions were present in 100%. Twenty-five percent did not have another in situ total joint arthroplasty, and the remaining patients did not have a metal-on-metal articulation that could lead to elevation in serum metal ion levels. Mean follow-up after the revision TKA was 8 months. Results. Mean serum cobalt, chromium, and titanium concentrations were 11 ng/mL, 6 ng/mL, and 3 ng/mL, respectively. Serum metal ion levels facilitated failure mechanism identification in 75%, which included modular junction failure (6 cases), constraint locking mechanism failure (3 cases), corrosion of modular metallic interfaces (2 cases), and
Periprosthetic fractures (PPFs) following hip arthroplasty are complex injuries. This study evaluates patient demographic characteristics, management, outcomes, and risk factors associated with PPF subtypes over a decade. Using a multicentre collaborative study design, independent of registry data, we identified adults from 29 centres with PPFs around the hip between January 2010 and December 2019. Radiographs were assessed for the Unified Classification System (UCS) grade. Patient and injury characteristics, management, and outcomes were compared between UCS grades. A multinomial logistic regression was performed to estimate relative risk ratios (RRR) of variables on UCS grade.Aims
Methods
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. 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.Aims
Methods
This study evaluates the association between consultant and hospital volume and the risk of re-revision and 90-day mortality following first-time revision of primary hip arthroplasty for aseptic loosening. We conducted a cohort study of first-time, single-stage revision hip arthroplasties (RHAs) performed for aseptic loosening and recorded in the National Joint Registry (NJR) data for England, Wales, Northern Ireland, and the Isle of Man between 2003 and 2019. Patient identifiers were used to link records to national mortality data, and to NJR data to identify subsequent re-revision procedures. Multivariable Cox proportional hazard models with restricted cubic splines were used to define associations between volume and outcome.Aims
Methods
During total knee replacement (TKR), surgeons can choose whether or not to resurface the patella, with advantages and disadvantages of each approach. Recently, the National Institute for Health and Care Excellence (NICE) recommended always resurfacing the patella, rather than never doing so. NICE found insufficient evidence on selective resurfacing (surgeon’s decision based on intraoperative findings and symptoms) to make recommendations. If effective, selective resurfacing could result in optimal individualized patient care. This protocol describes a randomized controlled trial to evaluate the clinical and cost-effectiveness of primary TKR with always patellar resurfacing compared to selective patellar resurfacing. The PAtellar Resurfacing Trial (PART) is a patient- and assessor-blinded multicentre, pragmatic parallel two-arm randomized superiority trial of adults undergoing elective primary TKR for primary osteoarthritis at NHS hospitals in England, with an embedded internal pilot phase (ISRCTN 33276681). Participants will be randomly allocated intraoperatively on a 1:1 basis (stratified by centre and implant type (cruciate-retaining vs cruciate-sacrificing)) to always resurface or selectively resurface the patella, once the surgeon has confirmed sufficient patellar thickness for resurfacing and that constrained implants are not required. The primary analysis will compare the Oxford Knee Score (OKS) one year after surgery. Secondary outcomes include patient-reported outcome measures at three months, six months, and one year (Knee injury and Osteoarthritis Outcome Score, OKS, EuroQol five-dimension five-level questionnaire, patient satisfaction, postoperative complications, need for further surgery, resource use, and costs). Cost-effectiveness will be measured for the lifetime of the patient. Overall, 530 patients will be recruited to obtain 90% power to detect a four-point difference in OKS between the groups one year after surgery, assuming up to 40% resurfacing in the selective group.Aims
Methods
Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models. Literature research was performed on PubMed and Embase databases. Keywords used for search criteria were “bone AND biofilm”. Information on the species of the animal model, bacterial strain, evaluation of biofilm and bone infection, complications, key findings on observations, prevention, and treatment of biofilm were extracted.Aims
Methods