Periprosthetic joint infection (PJI) is a devastating diagnosis that carries a significant rate of associated mortality and places a large burden on health care systems. Treatment protocols often include combined intravenous antibiotics and staged revision surgery with locally-delivered antibiotics via PMMA cement spacers and/or beads. One disadvantage of PMMA is the need for later removal. Antibiotic releasing Calcium Sulphate beads (CaSO4) have had promising results in revision joint surgery and are absorbable, making later removal unnecessary. We report on use in a tertiary referral centre in the UK and present our initial findings. CaSO4 beads containing 1 gram of Vancomycin and 240 mg of tobramycin per 10 cc was implanted in 12 patients between August 2012 and December 2012, all having undergone revision joint surgery for PJI. Of these patients; 7 were men and 5 women, mean age was 57 years (range 39–72) with a mean ASA grade of 2 (1–4). Indications were infected Total Hip Replacement (n = 7), infected Total Knee Replacement (n = 4) and infected metal on metal hip resurfacing (n = 1). Three procedures were emergencies, with the remainder being semi-elective procedures. One patient had single-stage revision THR. At latest follow up 10 patients had made a full recovery, with normal function and inflammatory markers. Two patients were awaiting a second stage revision procedure. Mean follow up was 2 months (1–4).Introduction:
Methods & Results:
Revision hip arthroplasty is a technically challenging operation as proximal bony deficits preclude the use of standard implants. Longer distally fixing stems are therefore required to achieve primary stability. This work aims to compare the primary stability and biomechanical properties of a new design of tapered fluted modular femoral stem (Redapt®, Smith & Nephew) to that of a conical fluted stem (Restoration®, Stryker). It is hypothesized that the taper will provide improved rotational stability under cyclical loading.Introduction
Aims
Revision surgery for total knee replacement is a complex procedure, carrying an increased risk for the patient and cost for hospitals. As well as increased cost of peri-operative investigations, blood transfusions, surgical instrumentation, implants and theatre time, there is a well documented increased length of stay (LOS), accounting for the majority of actual costs associated with surgery. We compared revision surgery for infection vs. other causes (aseptic loosening, dislocation, mal-alignment). Clinical, demographic and economic data were obtained for 180 consecutive revision total knee replacements performed at a tertiary referral centre between 2003 and 2012. Actual costs and National Health Service tariffs were compared per patient and mean difference calculated. Mean age was 66 years (range 17–87) with 62 male and 117 female patients. Mean LOS for aseptic cases was 10 days (range 1–62) and 20 days (range 4–103) for infection. Mean cost difference in aseptic cases (n = 125) was £−933 (SD = £12,204), and £−3907 (SD = £7,256) for infection (n = 54). Surgery for infection was associated with increased operating times, blood loss and complications compared to revision for aseptic causes. LOS for infection was on average double that for aseptic cases (p < 0.05). Current NHS tariffs do not fully reimburse the increased costs associated with providing a revision knee surgery service, with even greater cost incurred by the treating hospital for infected cases. These losses may negatively influence the provision of revision surgery in the NHS.
High failure rates with large diameter, metal on metal hip replacements have highlighted a potential issue with the head/stem taper junction as one of the significant sources of metal ion release. Postulated reasons as to why this may be such a problem with large head metal on metal hip replacements is due to the increased torque achieved by the larger head size. This may be responsible for applying greater micromotion between the head and stem taper and consequently greater amounts of fretting corrosion. The aim of this study was to perform short term in vitro electrochemical tests to assess the effect of increasing head diameter and torque on the fretting corrosion susceptibility of the head/stem taper interface and to investigate its effect on different material combinations. 36 mm Cobalt Chrome (CoCr) femoral heads were coupled with either a CoCr or Titanium (Ti) stem with 12/14 tapers, all with a smooth surface finish. Increasing perpendicular horizontal offsets in the sagittal plane created incremental increases in torque. Offset increments of 0 mm, 5.4 mm and 7.5 mm were selected (Figure 1) to simulate the torque force equivalent to 9 Nm, 12 Nm and 17 Nm. An inverted hip replacement setup was used (ASTM F1875-98) (Figure 2). Components were statically loaded at 0 kN and 2.3 kN prior to sinusoidal cyclic loading and electrochemical testing. Mean & fretting currents were calculated every 50 cycles up to a maximum of 1000 cycles of sinusoidal cyclic loading at 3 Hz along with the Overall Mean Current (OMC), Overall Mean Fretting Current (OMFC) and Overall Current change (OCC).Introduction:
Methods:
Preoperative anemia in patients undergoing elective total knee arthroplasty has been associated with increased allogeneic blood transfusion therapy and increased rates of in hospital morbidity, which often leads to a longer length of hospital stay. We measured the prevalence of anaemia among patients attending pre-admission clinic before elective major joint arthroplasty. Retrospectively, a randomized sample of all patients undergoing total hip arthroplasty between Dec 2009 and June 2010 were included. The computerized laboratory results were analysed for anaemia as defined by the local reference range (<11.5g/dL for females, <13g/dL for males). Patients were reviewed 6 weeks post operatively and range of flexion and extension was documented.AIM:
METHODS:
The principles of acetabular reconstruction include the creation of a stable acetabular bed, secure prosthetic fixation with freedom of orientation, bony reconstitution, and the restoration of a normal hip centre of rotation with acceptable biomechanics. Acetabular impaction grafting, particularly with cemented implants, has been shown to be a reliable means of acetabular revision. Whilst our practice is heavily weighted towards cementless revision of the acetabulum with impaction grafting, there is a large body of evidence from Tom Slooff and his successors that cemented revision with impaction grafting undertaken with strict attention to technical detail is associated with excellent long terms results in all ages and across a number of underlying pathologies including dysplasia and rheumatoid arthritis. We use revision to a cementless hemispherical porous-coated acetabular cup for most isolated cavitary or segmental defects and for many combined deficiencies. Morsellised allograft is packed in using chips of varied size and a combination of impaction and reverse reaming is used in order to create a hemisphere. There is increasing evidence for the use of synthetic grafts, usually mixed with allograft, in this setting. The reconstruction relies on the ability to achieve biological fixation of the component to the underlying host bone. This requires intimate host bone contact, and rigid implant stability. It is important to achieve host bone contact in a least part of the dome and posterior column – when this is possible, and particularly when there is a good rim fit, we have not found it absolutely necessary to have contact with host bone over 50% of the surface. Once the decision to attempt a cementless reconstruction is made, hemispherical reamers are used to prepare the acetabular cavity. Sequentially larger reamers are used until there is three-point contact with the ilium, ischium and pubis. Acetabular reaming should be performed in the desired orientation of the final implant, with approximately 200 of anteversion and 400 of abduction (or lateral opening). Removing residual posterior column bone should be avoided. Reaming to bleeding bone is desirable. Morsellised allograft is inserted and packed and/or reverse reamed into any cavitary defects. This method can also be applied to medial wall uncontained defects by placing the graft onto the medial membrane or obturator internus muscle, and gently packing it down before inserting the cementless acetabular component. Either the reamer heads or trial cups can be used to trial prior to choosing and inserting the definitive implant. The fixation is augmented with screws in all cases. Incorporation of the graft may be helped by the use of autologous bone marrow. Cementless acetabular components with impaction grafting should not be used when the host biology does not allow for stability or for bone ingrowth. This includes the severely osteopenic pelvis, pelvic osteonecrosis after irradiation, tumours, and metabolic bone disorders. They should also not be used in the presence of pelvic discontinuity unless the structure of the pelvic ring has been restored with a plate, or specialised materials/porous metals are used. The challenge of reconstituting the acetabulum depends on the degree and type of bone loss. The principles of maximising host bone-implant contact and implant stability have borne fruit in our experience with cementless revision. The advantages of bone grafting in acetabular reconstruction include the ability to restore bone stock, to rebuild a normal hip center and hip biomechanics and to increase bone stock for future revisions.
Periprosthetic fractures in total hip arthroplasty lead to considerable morbidity in terms of loss of component fixation, bone loss and subsequent function. The prevention, early recognition and appropriate management of such fractures are therefore critical. The pathogenesis of periprosthetic factors is multi-factorial. There are a number of intrinsic patient influences such as bone stock, biomechanics and compliance. There are also a host of extrinsic factors over which the surgeon has more control. The prevention of periprosthetic fractures requires careful pre-operative planning and templating, the availability of the necessary expertise and equipment, and knowledge of the potential pitfalls so that these can be avoided both intra-operatively and in follow-up. The key issues here are around identifying the risk, choosing the correct implant, understanding the anatomy, understanding the possible risks and avoiding them and using appropriate technique. There are a number of recognized risk factors for periprosthetic hip fractures. The prevalence of intra-operative fractures during total hip arthroplasty is higher in the patient with osteopenia/osteoporosis. Other conditions causing increased bone fragility, such as osteomalacia, Paget's disease, osteopetrosis, and osteogenesis imperfecta are also at a higher risk of intra-operative fracture. The use of more and more press fit cementless components has also increased the number of periprosthetic femoral fractures because of the force required to obtain such a fit. Complex deformities of the proximal femur, particularly when associated with a narrow medullary canal, as seen in secondary degenerative joint disease following developmental dysplasia of the hip may also increase the risk of intra-operative fractures. Revision surgery is associated with a higher risk of intra-operative fracture than primary hip replacement surgery. These fractures typically occur during hip dislocation, cement extraction, or reaming through old cement. Other risk factors for post-operative femoral fractures include loosening of the prosthesis with cortical bone loss, local osteolysis, stress risers within the cortex, such as old screw holes, the ends of plates, or impingement of a loose stem against the lateral femoral cortex. Periprosthetic acetabular fractures are increasingly recognized. This is in part due to the popularity of press fit components, which increase fracture risk both at the time of insertion and later due to medial wall stress shielding and pelvic osteolysis, and partly due to the increasing frequency of severe defects encountered at the time of revision surgery. Both over- and under-reaming are significant risk factors for acetabular fractures during total hip replacement. It is imperative to deal with the osteopenic patient gently and appropriately, being aware of the rim on the acetabular side and having the capacity for screw fixation where needed, having an understanding of where you wish to place your components and creating the appropriate runways for them, thinking about the stability of an implant as it is inserted and understanding that an implant that is less stable than expected probably is associated with either a size mismatch, a fracture or an implant that will not sit properly probably requires more or a different direction of reaming rather than harder blows with a hammer. A typical example where extra care is required is the scenario of a fractured neck of femur that requires total hip arthroplasty. The virgin native acetabulum in a patient likely to have some bony deficiency may be more difficult to deal with as it has a higher fracture risk. Pre-operative templating helps to identify the correct entry point for preparation of the lateral runway for linear insertion of a femoral stem. If resistance is met during insertion, the situation should be re-appraised to ensure that the direction and level of the rasp and prosthesis are the same. This reduces the risk of varus/valgus positioning which increases the risk of intra- and post-operative fractures. It is also important to avoid a change of version during insertion of the prosthesis as this can lead to high stresses.
Femoroacetabular impingement is defined as abnormal abutment between the femoral head, or the femoral head-neck junction, and the acetabulum. It is now established that FAI is a major etiological factor in the development of osteoarthritis (OA) of the hip. FAI is increasingly recognized as a cause of hip pain in young active individuals. Clinical features of FAI include pain in the groin but this may also be felt in the gluteal region, trochanteric region, or in the thigh. Symptoms most commonly begin as an intermittent discomfort, often during or following periods of repetitive hip motion e.g. running, walking, progressing to more constant and intense pain. Stiffness is common, with reductions in the range of hip flexion, and internal rotation in particular. Patients may also complain of clicking, popping, or snapping sensations in the affected hip. Operative treatment of FAI is principally aimed at removing cam lesions and increasing femoral head-neck offset (osteochondroplasty), and treating associated soft tissue lesions such as labral tears. Acetabular recession with labral reattachment is increasingly used for pincers lesions but great care is needed to ensure that the overall coverage of the hip is not reduced. As proficiency with arthroscopic techniques has improved, arthroscopic osteochondroplasty and labral debridement/repair has become increasingly popular for the treatment for FAI, with promising functional results in a range of studies. 150 consecutive patients who underwent hip arthroscopy for CAM type FAI with minimum 1 year follow up were prospectively studied. Patient satisfaction, non-arthritic hip score, re-operations and conversion to arthroplasty were analysed. There were a total of 90 males and 60 females. The average age group was 32 years (27 to 46 years). All patients underwent osteoplasty of the CAM lesion and stabilisation/ repair of the labral tears. A comparison of pre procedure non arthritic hip scores with the scores at latest follow up (minimum 1 year, maximum 3 years) showed a significant improvement (56 vs 86; p <0.01). There were 2 re operations for unresolved symptoms and 1 conversion to arthroplasty for continued pain associated with significant loss of articular cartilage. Perineal numbness was noted in 9 patients all of which resolved. No other major complications were noted in this series. Hip impingement symptoms resolved in all cases and a good (20 %) to excellent (75%) outcome was reported. Arthroscopic management of CAM type FAI is associated with subjective and objective improvement in hip function at early follow up. Longer follow-up is necessary to analyse the ability of this procedure to arrest progression of degenerative hip disease.
Acute infection following Total Hip Arthroplasty (THA) is a serious complication. It is commonly treated by irrigation and debridement (I&D) with component retention (exchange only the mobile parts of the joint - head and liner). However, the reported re-infection rate with the use of this approach remains high. We are reporting our experience in using single - stage revision arthroplasty in treating acute infection of THA. We hypothesized that the infection control rate after immediate early revision for acute infection of cementless implants is better than has been reported for I&D with exchange of mobile parts. From our infection arthroplasty database, we reviewed the outcome of 19 patients who had an acute infection (within 6 weeks) of cementless THA. Our management strategy includes I&D and single-stage (direct-exchange) revision arthroplasty followed by 6 weeks course of culture specific oral antibiotics.Introduction
Methods
Technology in Orthopaedic surgery has become more widespread in the past 20 years, with emerging evidence of its benefits in arthroplasty. Although patients are aware of benefits of conventional joint replacement, little is known on patients' knowledge of the prevalence, benefits or drawbacks of surgery involving navigation or robotic systems. In an outpatient arthroplasty clinic, 100 consecutive patients were approached and given questionnaires to assess their knowledge of Navigation and Robotics in Orthopaedic surgery. Participation in the survey was voluntary.Introduction
Materials & Methods
Arthroplasty performed for the partial or complete resurfacing, remodelling or replacement of a degenerative or dysfunctional joint is a common procedure. The number of total knee and hip arthroplasty procedures performed per year are increasing with the number of total knee arthroplasties (TKA) predicted to more than double by 2030. Although this provides dramatic relief from pain, these implants do have a limited lifespan. Approximately 10% of total hip arthroplasty (THA) implants require revision due to periprosthetic osteolysis. Approximately 40% require revision due to aseptic loosening believed to be due to polyethylene wear. Arthroplasty prostheses may also fail due to deep infection, malpositioned or oversized implants and peri-prosthetic fractures. It is difficult to predict which patients will develop complications. Therefore follow up has typically involved serial clinical and radiographic assessments for the lifetime of the patient. Despite many collective years of experience there is still disparity in the follow-up of such patients. Elective arthroplasty forms the major bulk of workload in trauma and orthopaedic surgery. Efficient service provision and planning requires an agreed, evidence-based protocol. Currently no consensus exists, however there are many papers detailing the effectiveness of imaging techniques as well as the need for timed clinical assessments. The authors review current literature regarding hip and knee arthropalsty procedures, potential causes of failure and methods of detection in order to highlight areas of potential future research to enable an evidence-based protocol to be derived.
In Total Hip Arthroplasty (THA), polyethylene wear reduction is key to implant longevity. Oxidized Zirconium (OxZi) unites properties of a ceramic bearing surface and metal head, producing less wear in comparison to standard Cobalt-Chromium (CoCr) when articulating with Cross-linked polyethylene (XLPE) in vitro. This study investigates in vivo polyethylene (PE) wear, outcomes and complications for these two bearing couples in patients at 5 year follow-up 400 patients undergoing THA across four institutions were prospectively randomised into three groups. Group I received a cobalt-chrome (CoCr) femoral head/ cross-linked polyethylene (XLPE) liner; Group II received an OxZi femoral head/ ultrahigh molecular weight polyethylene (UHMWPE) liner; Group III received an OxZi femoral head/XLPE liner. All bearing heads were 32 mm. Linear wear rate was calculated with Martell computer software. Functional outcome and complications were recorded.Introduction
Methods
The purpose of this study was to evaluate the functional outcome in the medium and long-term of hip resurfacing in comparison with cementless hip replacement in patients under the age of 55. Eighty patients were enrolled between 1999 and 2002. Twenty-four were randomised (11 hip re-surfacing, 13 total hip replacement), 18 refused hip resurfacing and chose cementless total hip replacement with a 32 mm bearing, 38 insisted on re-surfacing. All the patients have been reviewed at a minimum follow-up of 8 years and a mean of 10.1 years. Patients were assessed clinically and radiographically at one year, five years, eight years and ten years. Outcome measures included EQ 5, SF 36, Oxford, Harris hip, UCLA and UCH scores.Introduction
Methods
Technology in Orthopaedic surgery has become more widespread in the past 20 years, with emerging evidence of its benefits in arthroplasty. Although patients are aware of benefits of conventional joint replacement, little is known on patients' knowledge of the prevalence, benefits or drawbacks of surgery involving navigation or robotic systems. In an outpatient arthroplasty clinic, 100 consecutive patients were approached and given questionnaires to assess their knowledge of Navigation and Robotics in Orthopaedic surgery. Participation in the survey was voluntary.Introduction
Materials and methods
Adductor muscle and tendon injuries are commonly seen in sport. Complete adductor avulsions have been described and can be managed non-operatively or operatively. A rare variant of this injury is the complete avulsion of the adductor complex with the pectineus and rectus abdominus amounting to a complete sleeve avulsion from the pubis. This is a severe injury that is increasingly recognised due to improved imaging and lower diagnostic threshold. We describe the surgical management of twelve athletes with this severe injury.Background
Purpose
Wound surveillance has been reported to result in a significant fall in the incidence of wound sepsis in total knee arthroplasty (TKA). However, there is currently little guidance on the definition of surgical wound infection that is best to be used for surveillance. The purpose of this study was to assess the agreement between three common definitions of surgical wound infection as a performance indicator in TKA; (a) the CDC 1992 definition, (b) the NINSS modification of the CDC definition and (c) the ASEPSIS scoring method applied to the same series of surgical wounds. A prospective study of 500 surgical wounds in patients who underwent knee arthroplasties between May 2002 and December 2004 from a single tertiary centre were assessed according to the different definitions of surgical wound infection.Introduction
Methods
Intraosseous transcutaneous amputation prostheses (ITAP) provide an alternative means of attaching artificial limbs for amputees. Conventional stump-socket devices are associated with soft tissue complications including; pressure sores and tissue necrosis. ITAP resolves these problems by attaching the exo-prosthesis transcutaneously to the skeleton. The aim of this study is to increase the attachment of dermal fibroblasts to titanium alloy in vitro. Fibronectin (Fn) and laminin 332 (Ln) enhance early cell growth and adhesion. We hypothesize that silanized dual coatings of fibronectin and laminin (SiFnLn) will be more durable when compared with adsorbed dual coating (AdFnLn), and will enhance early fibroblast growth and adhesion compared to single coatings. The kinetics of dual single and dual protein coating attachment onto titanium alloy was quantified on silanized 10mm diameter discs using radiolabelled Fn (125I-Fn) and Ln (125I-Ln). Sixty discs were polished, sterilized and silanized. Coating durability was assessed when soaked in fetal calf serum (FCS) for 0, 1, 24, 48 and 72hrs. Data was compared to un-silanized Ti discs with the same coatings. Five thousand human dermal fibroblasts were seeded on discs (n = 6) of Ti polished alone (Pol), Ti with adsorbed fibronectin (AdFn), Ti with adsorbed laminin (AdLn), Ti adsorbed dual coating (AdFnLn), Ti silanized (Si), Ti silanized with fibronectin (SiFn), Ti silanized with laminin (SiLn), Ti silanized with a dual coating (SiFnLn) for 24hrs. In order to measure cell adhesion fibroblasts were fixed, vinculin stained using mouse vinculin antibody and alexa fluor. Axiovision Image Analysis software was used to measure cell area, vinculin focal adhesion markers per cell and per unit cell area. Data was analysed in SPSS and significance was assumed at the 0.05 level.Introduction
Methods
Following amputation, residual stumps used to attach the external prostheses can be associated with sores, infection and skin necrosis. These problems could be overcome by off loading the soft tissues. Intraosseous transcutaneous amputation prostheses (ITAP) attach external implants directly to residual bone reducing these complications. However, a tight seal at the skin implant interface is crucial in preventing epithelial down-growth and infection. Fibronectin (Fn) and laminin 332 (Ln), enhance early cell growth and adhesion of keratinocytes. Silanization to titanium alloy (Ti) allows these proteins to bond to the metal directly. We hypothesize that silanized dual coatings of fibronectin and laminin (SiFnLn) will be more durable than absorbed proteins and that keratinocyte adhesion will be increased compared with Ti controls and single silanized proteins. 10 mm diameter Ti alloy discs were polished, sterilized and silanized. The kinetics of silanized single and dual protein coating attachment onto titanium alloy was quantified using radio-labelled Fn(125I-Fn) and Ln(125I-Ln). Coating durability was assessed when soaked in fetal calf serum (FCS) for 0, 1, 24, 48, 72hrs. Data was compared to un-silanized Ti discs with the same amount of adsorbed proteins. In order to study cell attachment 20 × 103 keratinocytes were seeded on the discs (n = 6): silanized (Si), silanized fibronectin (SiFn), silanized laminin (SiLn), silanized dual coating (SiFnLn) for 1, 4 and 24hrs. Adhesion of cells was assessed using mouse vinculin antibody for 2hrs and alexafluor for 1hr which stains focal adhesions responsible for attaching cells to surfaces. Axiovision Image Analysis software was used to measure cell area, vinculin markers per cell unit and per unit cell area on 15 cells per disc. Data was analysed in SPSS and significance was assumed at the 0.05 level.Introduction
Methods
The number of revision hip arthroplasty procedures is rising annually with 7852 such operations performed in the UK in 2010. These are expensive procedures due to pre-operative investigation, surgical implants and instrumentation, protracted hospital stay, and pharmacological costs. There is a paucity of robust literature on the costs associated with the common indications for this surgery. We aim to quantify the cost of revision hip arthroplasty by indication and identify any short-fall in relation to the national tariff.Introduction
Objective
Premature cessation of clopidogrel in certain patients with cardiac conditions is associated with an increased risk of recurrent coronary events. Such patients often present with proximal femoral fractures requiring surgical intervention. Our aim was to ascertain whether it is necessary to stop clopidogrel preoperatively to avoid postoperative complications following hip hemiarthroplasty surgery. A retrospective review of 102 patients with ongoing clopidogrel therapy and patients not on clopidogrel who underwent hip hemiarthroplasty for an intracapsular proximal femoral fracture was undertaken. Statistical comparison on pre- and postoperative haemoglobin (Hb), ASA grades, comorbidities, operative times, transfusion requirements, hospital length of stay (LOS), wound infection, haematoma and reoperation rates between the two groups was undertaken.Introduction
Methods
