There is limited evidence in the literature suggesting that ceramic-on-ceramic (CoC) THA is associated with lower risk of revision for prosthetic joint infection (PJI) than other bearing combinations especially metal-on-polyethylene (MoP) and metal-on-metal (MoM). Pitto and Sedel reported hazard ratios of 1.3 – 2.1 for other bearing surfaces vs. CoC. Of interest, the PJI rate was not significantly lower in the first 6 months, when most infections occur, but only became significant in the long term. While factors such as patient age, fixation, mode, O.R. type, use of body exhaust suits, and surgeon volume were considered in the multivariate analysis, BMI, medical comorbidities, and ASA class were not. This is a major weakness that casts doubt on the conclusion, since those three factors are MAJOR risk factors for PJI AND all three factors are more likely to be unevenly distributed, much more likely present in groups other than CoC. The data was also limited by the fact that it was drawn from a retrospective review of National Registry data, The New Zealand Joint Registry. While similar findings have recently been reported from the Australian Joint Registry, the danger in attributing differences in outcomes to implants alone is possibly the single greatest danger in interpreting registry results. While device design can impact implant survival, other factors such as surgical technique, surgeon, hospital, and especially patient factors have a far greater likelihood of explaining differences in observed results. A recent report from the same New Zealand joint registry reported that obesity, ASA class, surgical approach, and trainee operations all were associated with higher PJI and all would be more likely in non-CoC THAs. Accuracy of diagnosis is also a major concern. Revision for trunnionosis is more common in non-CoC THA and is frequently misdiagnosed as PJI.

Numerous non-registry studies and reviews have compared PJI in CoC vs. other bearing and none have concluded than the incidence of PJI differed significantly.

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intraoperative fracture) are careful preoperative planning and more recently, the option of intraoperative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intraoperative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the preoperative plan intraoperatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results.

A pilot study at Washington University demonstrated that intraoperative imaging was able to eliminate outliers for acetabular inclination and anteversion. In addition, the ability to achieve accurate reproduction of femoral offset and limb length within 5mm was three times better with intraoperative imaging (P < 0.001).

In years past, the most common reason for revision following knee replacement was polyethylene wear. A more recent study indicates that polyethylene wear is relatively uncommon as a cause for total knee revision counting for only 10% or fewer of revisions. The most common reason for revision currently is aseptic loosening followed closely by instability and infection. The time to revision was surprisingly short. In a recent series only 30% of knees were greater than 5 years from surgery at the time of revision. The most common time interval was less than 2 years. This is likely because of the higher incidence of infection and instability that occurs most commonly at a relatively early time frame. Evaluation of a painful total knee should take into account these findings. All total knees that are painful within 5 years of surgery should be assumed to be infected until proven otherwise. Therefore, virtually all should be aspirated for cell count, differential, and culture. Alpha-defensin is also available in cases in which a patient may have been on antibiotics within a month or less, as well as cases in which diagnosis is a challenge for some reason. Instability can be diagnosed with physical exam focusing on mid-flexion instability which can be usually determined with the patient seated and the knee in mid-flexion, with the foot flat on the floor at which point sagittal plane laxity can be discerned. This is also frequently associated with symptoms of giving way and recurring effusions and difficulty descending stairs. A new phenomenon of tibial de-bonding has been described, which can be a challenge to diagnose. Radiographs can appear normal when loosening occurs between the implant and the cement mantle. This seems to be more common with the use of higher viscosity cement. Obviously this is technique dependent since good results have been reported with the use of high viscosity cement. Component malposition can cause stiffness and pain and relatively good results have been reported by component revision when malrotation has been confirmed with CT scan. When infection, instability and loosening are not present, extra-articular causes should be ruled out including lumbar spine, vascular compromise, complex regional pain syndromes and fibromyalgia, and peri-articular causes such as bursitis, tendonitis, tendon impingement among others. One of the most common causes of pain following total knee is unrealistic patient expectations. Performing total knee replacement in early stages of arthritis with only mild to moderate symptoms and radiographic changes has been associated with persistent pain and dissatisfaction. It may be prudent to obtain the immediate preoperative x-rays to determine if early intervention was undertaken and patients have otherwise normal appearing total knee x-rays and a negative work up. A recent study indicated that this was likely a cause or a major contributing factor to persistent pain following otherwise a well performed knee replacement. A national multicenter study of the appropriateness of indications for TKA also indicated that early intervention was a major cause of persistent pain, dissatisfaction, and failure to improve following total knee replacement.

Introduction

Multimodal pain management strategies are now commonplace in perioperative management of total knee arthroplasty (TKA), although controversy remains regarding the role of adductor canal blocks (ACB) in this algorithm. Proposed benefits include theoretical decreased role of perioperative narcotic pain medication, improved function with physical therapy postoperatively, shorter duration of hospital stay and improved patient satisfaction. Those opposed cite increased cost and risk of complications including inadvertent motor blockade. The purpose of this study was to independently evaluate the effect of adductor canal block on short-term post-operative outcomes including (1) length of stay (LOS), (2) post-operative narcotic utilization, and (3) function with physical therapy in the era of modern TKA.

To assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular dual mobility acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design.

This was a prospective study of patients  65 years of age, with a BMI  35 kg/m², and UCLA activity score > 6 who received a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. All patients had a minimum of 2-year clinical follow-up.

Patient reported outcome measures, whole blood metal ion levels (ug/L), and periprosthetic femur BMD were measured at baseline and at 1- and 2-years postoperatively.

43 patients (30 male, 13 female; mean age 52.6 ± 6.5 years) were enrolled. Harris Hip Scores improved from 54.1 ± 20.5 to 91.2 ± 10.8 at 2 years postoperatively (p<0.001). All patients had radiographically well-fixed components, no patients have sustained an instability event, and no patients have required a return to the operating room or revision procedure.

Mean cobalt levels increased from 0.065 ± 0.03 ug/L preoperatively to 0.30 ± 0.51 at 1-year postoperatively (p=0.01), but decreased at 2 years postoperatively to 0.16 ± 0.23 (p=0.2) (Table 1). Four patients (9.3%) had a cobalt level outside the reference range (0.03 to 0.29ug/L) at 2 years postoperatively with values from 0.32 to 0.94. None were symptomatic

The mean femoral BMD ratio was maintained in Gruen zones 2 thru 7 at both 1- and 2-years postoperatively using this stem design (Table 2). At 2 years postoperatively, BMD in the medial calcar was 101.5% of the baseline value.

Use of a modular dual mobility prosthesis and cementless, tapered femoral stem has shown encouraging results in young, active patients undergoing primary THA. Elevation in mean cobalt levels and the presence of four patients outside the reference range at 2 years postoperatively demonstrates the necessity of continued surveillance in this cohort.

For any figures or tables, please contact authors directly: barrackr@wustl.edu

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intra-operative fracture) are careful pre-operative planning and more recently, the option of intra-operative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intra-operative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the pre-operative plan intra-operatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results.

A pilot study at Washington University demonstrated that intra-operative imaging was able to eliminate outliers for acetabular inclination and anteversion. In addition, the ability to achieve accurate reproduction of femoral offset and limb length within 5mm was three times better with intra-operative imaging (P <0.001).

There is limited evidence in the literature suggesting that ceramic-on-ceramic (CoC) THA is associated with lower risk of revision for prosthetic joint infection (PJI) than other bearing combinations especially metal-on-poly (MoP) and metal-on-metal (MoM). Pitto and Sedel reported hazard ratios of 1.3 – 2.1 for other bearing surfaces versus CoC. Of interest, the PJI rate was not significantly lower in the first 6 months, when most infections occur, but only became significant in the long term. While factors such as patient age, fixation, mode, OR type, use of body exhaust suits, and surgeon volume were considered in the multivariate analysis, BMI, medical comorbidities, and ASA class were not. This is a major weakness that casts doubt on the conclusion, since those three factors are MAJOR risk factors for PJI AND all three factors are more likely to be unevenly distributed, and much more likely present in groups other than CoC. The data was also limited by the fact that it was drawn from a retrospective review of National Registry data, The New Zealand Joint Registry. While similar findings have recently been reported from the Australian Joint Registry, the danger in attributing differences in outcomes to implants alone is possibly the single greatest danger in interpreting registry results. While device design can impact implant survival, other factors such as surgical technique, surgeon, hospital, and especially patient factors have a far greater likelihood of explaining differences in observed results. A recent report from the same New Zealand joint registry reported that obesity, ASA class, surgical approach, and trainee operations all were associated with higher PJI and all would be more likely in non-CoC THAs. Accuracy of diagnosis is also a major concern. Revision for trunnionosis is more common in non-CoC THA and is frequently misdiagnosed as PJI.

Numerous non-registry studies and reviews have compared PJI in CoC vs. other bearings and none have concluded than the incidence of PJI differed significantly.

Total hip arthroplasty (THA) is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined an appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA.

The current generation metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify.

To generate data on the level of function of younger more active arthroplasty patients, a national multicenter survey was conducted by an independent university medical interviewing center with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centers throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. In another study of over 400 THA and SRA patients at two major academic centers, patients completed pain drawings that revealed an equivalent incidence of groin pain between THA and SRA, but an incidence of thigh pain in THA that was three times higher than in SRA in young active patients.

While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilization and investigation of this procedure.

Surface replacement arthroplasty (SRA) has been proposed as a viable option for the treatment of osteoarthritis in young, active patients. Positive results of the Birmingham Hip Resurfacing (BHR) in select patient groups have been described in international series and registry data. We report 5–10 year U.S. follow-up for the BHR at our high volume institution.

314 patients (361 hips) between 2006–2011 underwent BHR at our institution and agreed to participate in research. Demographic features, modified Harris Hip Score, UCLA Activity Score, and satisfaction were recorded for patients with minimum 5-year follow-up (90%). Radiographs were evaluated for implant position and “at risk” signs. Complications, reoperations, and revisions were investigated.

Mean modified Harris Hip and UCLA scores significantly improved postoperatively to scores of 89.96 and 7.90 (p < 0.001), respectively. Kaplan-Meier estimated survival for all-cause revision was 96.7% [95% CI 94.7 – 98.7%] at 5 years and 91.5% [95% CI 85.3 – 97.6%] at 10 years. Estimated survival for aseptic revision in males less than 60 years old with a primary diagnosis of osteoarthritis was 99.5% [95% CI 98.7 – 100%] at 5 years and 98.8% [95% CI 97.0 – 100%] at 10 years. 14 patients required revision, including 5 revisions for adverse local tissue reaction.

Our study demonstrated excellent survivorship and clinical outcomes at 5–10 year follow up for the BHR. These results mirror other series and registry data published outside of the United States. Continued long-term follow-up and additional studies are necessary to validate the long-term safety and outcomes of the BHR, especially in young active arthroplasty patients.

Aims

The aims of this study were to examine the rate at which the positioning of the acetabular component, leg length discrepancy and femoral offset are outside an acceptable range in total hip arthroplasties (THAs) which either do or do not involve the use of intra-operative digital imaging.

The number of arthroplasties being performed increases each year. Patients undergoing an arthroplasty are at risk of venous thromboembolism (VTE) and appropriate prophylaxis has been recommended. However, the optimal protocol and the best agent to minimise VTE under these circumstances are not known. Although many agents may be used, there is a difference in their efficacy and the risk of bleeding. Thus, the selection of a particular agent relies on the balance between the desire to minimise VTE and the attempt to reduce the risk of bleeding, with its undesirable, and occasionally fatal, consequences.

Acetylsalicylic acid (aspirin) is an agent for VTE prophylaxis following arthroplasty. Many studies have shown its efficacy in minimising VTE under these circumstances. It is inexpensive and well-tolerated, and its use does not require routine blood tests. It is also a ‘milder’ agent and unlikely to result in haematoma formation, which may increase both the risk of infection and the need for further surgery. Aspirin is also unlikely to result in persistent wound drainage, which has been shown to be associated with the use of agents such as low-molecular-weight heparin (LMWH) and other more aggressive agents.

The main objective of this review was to summarise the current evidence relating to the efficacy of aspirin as a VTE prophylaxis following arthroplasty, and to address some of the common questions about its use.

There is convincing evidence that, taking all factors into account, aspirin is an effective, inexpensive, and safe form of VTE following arthroplasty in patients without a major risk factor for VTE, such as previous VTE.

Cite this article: Bone Joint J 2017;99-B:1420–30.

Total hip arthroplasty is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA.

The current generation metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify.

To generate data on the level of function of younger more active arthroplasty patients, a national multicenter survey was conducted by an independent university medical interviewing center with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centers throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. In another study of over 400 THA and SRA patients at two major academic centers, patients completed pain drawings that revealed an equivalent incidence of groin pain between THA and SRA, but an incidence of thigh pain in THA that was three times higher than in SRA in young active patients.

While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilisation and investigation of this procedure.

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intra-operative fracture) are careful pre-operative planning and more recently, the option of intra-operative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intra-operative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the pre-operative plan intra-operatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results.

The role of metal sensitivity or allergy in causing persistent symptoms or failure and need for a revision of a total joint replacement has been the topic of debate and controversy for decades. There was renewed interest in this area with the rise of metal-on-metal hip arthroplasty and the advent of adverse local tissue reactions. This led to an increase in metal ion testing as well as metal sensitivity testing. With the decline of the use of metal-on-metal hip components, this is now mostly an issue in knee arthroplasty. It is well known that a substantial percentage of patients have persistent symptoms following knee replacement. What remains in question is whether allergy to metal or other materials such as PMMA may be a contributing factor. It is accepted that the incidence of positive skin patch tests is higher in symptomatic failed joint replacements. Nickel sensitivity is most common as a positive skin test with up to 15% of patients demonstrating this followed by chromium and cobalt. A recent review by Lachiewicz et al. concluded that there was insufficient evidence to recommend routine or widespread cutaneous or in vitro hypersensitivity testing before primary TKA, that there is no evidence-based rationale to recommend a routine metal allergy screening questionnaire, that there is only anecdotal support for Ni-free implants, and that local dermatitis should be treated with topical steroids. In another article, routine screening for metal allergy was not recommended, however, selective screening for history of sensitivity or unexplained pain or early loosening was suggested. Other experts have recommended a role for utilizing a commercially available alternative to components containing nickel or cobalt in patients thought to be hypersensitive. A recent study, however, concluded that there was no difference in complications, revisions, or reoperations among patients who tested positive with patch testing whether they were treated with standard components or nickel free components. Likewise, a consensus panel published results from the United Kingdom in which cobalt chrome implants were recommended regardless of the patients metal allergy status. Patient perception is important, however, and among patients who report multiple allergies of any kind, a higher percentage are likely to be dissatisfied with their knee replacement. Of more importance are those reporting a specific allergy to metal are substantially more likely to express some dissatisfaction with their components.

Metal allergy as a cause of chronic pain and/or early failure of joint replacement is rare if it exists at all. It is always a diagnosis of exclusion. Patients who think they are allergic are probably more likely to be more symptomatic following joint replacement. Whether or not to use a nickel free or hypoallergenic component in such patients remains an area of controversy.

Resurfacing the patella is performed the majority of the time in the United States and in many regions it is considered standard practice. In many countries, however, the patella is left un-resurfaced an equal amount of the time or even rarely ever resurfaced. Patella resurfacing is not a simple or benign procedure. There are numerous negative sequelae of resurfacing including loosening, fragmentation, avascular necrosis, lateral facet pain, stress fracture, acute fracture, late fracture, and restricted motion. In a study by Berend, Ritter, et al, failures of the patella component were reported 4.2% of the time at an average of only 2.6 years. A study was undertaken at Washington University in recent years to determine rather more clinical problems were observed following total knee replacement with or without patella resurfacing. Records were maintained on all problem total knees cases with well localised anterior knee pain. The referral area for this clinic is St. Louis which is among the largest American cities, with the highest percentage of total knees that are performed without patella resurfacing. During 4 years of referrals of total knee patients with anterior knee pain, 47 cases were identified of which 36 had a resurfaced patella and 11 had a non-resurfaced patella. Eight of 36 resurfaced patellae underwent surgery while only 2 of 11 non-resurfaced patellae underwent subsequent surgery. More than 3 times as many painful total knees that were referred for evaluation had already had their patella resurfaced. In spite of the fact that approximately equal number of total knees were performed in this area without patella resurfacing, far more patients presented to clinic with painful total knee in which the patella had been resurfaced. The numerous pathologies requiring a treatment following patella resurfacing included patella loosening, fragmentation of the patella, avascular necrosis patella, late stress fracture, lateral facet pain, oblique resurfacing, and too thick of a patellar composite. In a large multi-center randomised clinical trial at 5 years from the United Kingdom in over 1700 knees from 34 centers and 116 surgeons, there was no difference in the Oxford Score, SF-12, EQ-5D, or need for further surgery or complications. The authors concluded, “We see no difference in any score, if there is a difference, it is too small to be of any clinical significance”. In a prospective of randomised clinical trial performed at Tulane University over 20 years ago, no differences were observed in knee score, a functional patella questionnaire, or the incidence of anterior knee pain between resurfaced and un-resurfaced patellae at time intervals of 2–4 years, 5–7 years, or greater than 10 years. Beyond 10 years the knee scores of total knee patients with a resurfaced patella had declined significantly greater than those with a non-resurfaced patella. There are numerous advantages of not resurfacing the patella including less surgical time, less expense, a lower risk of “major” complications (especially late complications), and if symptoms develop in an un-resurfaced patella, it is an easier salvage situation with more options available. A small percentage of total knee patients will be symptomatic whether or not their patella is resurfaced. Not resurfacing the patella retains more options and has fewer complications. The major determinant of clinical result and the presence of anterior knee pain after knee replacement is surgical technique and component design not whether or not the patella is resurfaced. Patella resurfacing is occasionally necessary for patients with inflammatory arthritis, a deformed or maltracking patella, or symptoms and pathology that are virtually restricted to the patellofemoral joint. For the vast majority of patients, however, patella resurfacing is not necessary.

Total hip replacement is among the most successful interventions in medicine and has been termed “The Operation of the Century”. Most major problems have been solved including femoral fixation, acetabular fixation, and wear. With a success rate of over 95% at 10 years in both hip and knee arthroplasty in a number of studies, the question remains as to whether the current status quo is optimal or acceptable. The literature, however, reports are from centers that represent optimised results and registry data, including the Medicare database, indicates that substantial short-term problems persist. The major issue is the variability in the performance of the procedure. The inability to consistently position components, particularly the acetabular component, results in major problems including instability and limb length discrepancy. A report by Malchau, et al. reveals that even among the best surgeons, optimal acetabular component positioning is only achieved 50% of the time. The penalty for missing the target is increased incidence of instability, increased wear rate, and diminished function due to restricted motion. Complications are related to position and a major potential explanation is the impact of patient position. Traditional imaging presents a two-dimensional rather than three-dimensional view of the patient and the patient is in a supine, non-functional position at the time that imaging is performed. Adverse events attributed to malposition, however, occur in functional positions and there is evidence that the orientation of the pelvis changes from the supine position at which imaging is performed. This topic has been studied extensively on three continents and the consensus is that the pelvis shifts on the order of 30–40 degrees from the supine to standing and sitting and furthermore, the acetabular component position changes proportionally with the rotation of the pelvis that occurs. How do we incorporate this information into imaging arthroplasty patients? This would require imaging the entire body, acquiring AP and lateral images simultaneously so that 3D imaging can be performed, performing imaging in a functional position (standing or sitting) and optimally at a lower radiation dose since these patients have repeated images and therefore a cumulative radiation dose over their lifetime. This technology was FDA approved for use in the hip and knee in 2011 and pilot studies have been performed at Washington University School of Medicine in St. Louis to validate the number of the hip and knee arthroplasty applications.

In conclusion, weightbearing and rotation have substantial impact on the standard measurements obtained before and after hip and knee arthroplasty. These differences in measurements between supine, sitting, and standing as well as correction for rotation may explain the lack of a stronger correlation between component position and a variety of complications that are observed such as variability in wear rates as well as instability. In knee arthroplasty, the change in mechanical axis that occurs from restoring all of patients to a neutral mechanical axis may explain some of the persistent pain and dissatisfaction that has been recently been reported at a relatively high percentage of knee arthroplasty patients. Because of the numerous potential clinical implications of three-dimensional weightbearing imaging, it is likely that the future of arthroplasty imaging will focus on functional three-dimensional imaging of the patient.

Tourniquet use in total knee arthroplasty is convenient for the surgeon and provides a bloodless field for expeditious surgery and a dry field for cementation, but can best be described as an orthopaedic tradition. It is logical for complex anatomy of ligament, nerve, and vessel surgery but it may not be necessary for total knee replacement. In one recent randomised trial, the absence of the tourniquet was not found to affect the quality of cement fixation. There are numerous potential downsides to the use of a tourniquet including decrease range of motion, delayed recovery, increased pain, wound complications, micro-emboli, neuropathy, and increased VTE. There are also a number of complications associated with the use of a tourniquet including arterial thrombosis, skin irritation below the tourniquet, post-operative hyperemia, blood loss, less accurate intra-operative assessment, and it complicates intravenous drug administration. Studies of range of motion have shown that when there is a difference noted, the range of motion is consistently better without tourniquet use. When a tourniquet is utilised it has been found to be advantageous to only use of tourniquet for a minimal amount of the case, typically when cementing is performed. Functional strength has also been found to be improved without the use of a tourniquet. This was attributed to muscle damage, tourniquet-induced ischemia, and compressive injury. Increased peri-operative pain has also been reported in randomised trials associated with the use of a tourniquet. Edema, swelling, and limb girth issues have also been noted to be associated with tourniquet use. Exsanguinating a limb will result in swelling approximately 10% of the original volume half due to a return of blood, and half due to reactive hyperemia. Longer tourniquet times are also associated with increased wound drainage and more wound hypoxia. Tourniquet use has also been associated with embolic phenomenon with several times greater risk of large emboli associated with tourniquet use.

A number of complications have been associated with tourniquet use including thromboembolic complications. In one study where quantitative MRI was utilised on both thighs after unilateral total knee replacement with and without a tourniquet, the tourniquet group showed more atrophy with a loss of 20% of the volume compared to the normal side in total knees performed with a tourniquet which also performed clinically worse. There is a small but substantial risk of arterial thrombosis particularly in patients that have atherosclerotic plaque. Ironically there is a risk of increased post-operative blood loss due to the post-tourniquet “blush” as the blood pressure and pain increase hours after a surgical procedure is completed. There is also difficulty in identifying and coagulating posterior and lateral geniculate vessels with the components in place. Utilizing a tourniquet also interferes with intra-operative assessment of patella tracking, range of motion, ligament stability, and gap balancing. Randomised clinical trials have concluded that there is less pain and quicker recovery without the use of a tourniquet. There have also been reports of less swelling, increased range of motion, less analgesic use and better clinical outcome when a tourniquet is not utilised. A meta-analysis of systematic reviews favored not utilizing a tourniquet due to the decrease in complication rate and the improvement in clinical results. While it is standard practice in the US to utilise a tourniquet, the strong consensus of the literature on the subject favors either not using a tourniquet or minimizing the use of a tourniquet for the period of time necessary for a very dry field for cement fixation.

Obesity is a leading public health concern and it is increasing in prevalence over the last 20 years. Obesity prevalence has doubled in adults and tripled in adolescents. The United States is the leading country in terms of percent obesity. Most alarming is the fact that the fastest growing rates of obesity are in the highest BMI groups. The issue of obesity is a particular concern to arthroplasty surgeons since there is an association between the increasing incidence of obesity and the increasing rate of joint replacement. Also of concern is that obese patients tend to be younger and complication rates and revision rates are higher in young patients which is only compounded by the presence of obesity. The risk of virtually every major complication is substantially higher in obese patients. Of concern, however, is a recent study indicating that bariatric surgery with successful weight loss does not necessarily decrease the complication rate. Obesity is also associated with substantially higher costs. There is some evidence that obesity doesn't necessarily affect implant survival. There is also evidence that the clinical outcomes may not be substantially compromised by the presence of obesity. Based on data from studies such as this, some centers have stated that it is difficult to justify withholding surgery based on BMI alone. The data on weight loss following surgery indicates the vast majority of patients did not lose weight following joint replacement. In one study a higher proportion of patients gained weight than lost weight.

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intraoperative fracture) are careful preoperative planning and more recently, the option of intraoperative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intraoperative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the preoperative plan intraoperatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results.

Resurfacing the patella is performed the majority of the time in the US and in many regions it is considered standard practice. In many countries, however, the patella is left unresurfaced an equal amount of the time or even rarely ever resurfaced. Patella resurfacing is not a simple or benign procedure. There are numerous negative sequelae of resurfacing including loosening, fragmentation, avascular necrosis, lateral facet pain, stress fracture, acute fracture, late fracture, and restricted motion. In a study by Berend, Ritter, et al, failures of the patella component were reported 4.2% of the time at an average of only 2.6 years. A study was undertaken at Washington University in recent years to determine whether more clinical problems were observed following total knee replacement with or without patella resurfacing. Records were maintained on all problem total knees cases with well localised anterior knee pain. The referral area for this clinic is St. Louis which is among the largest American cities, with the highest percentage of total knees that are performed without patella resurfacing. During 4 years of referrals of total knee patients with anterior knee pain, 47 cases were identified of which 36 had a resurfaced patella and 11 had a non-resurfaced patella. Eight of 36 resurfaced patellae underwent surgery while only 2 of 11 non-resurfaced patellae underwent subsequent surgery. More than 3 times as many painful total knees that were referred for evaluation had already had their patella resurfaced. In spite of the fact that approximately equal number of total knees were performed in this area without patella resurfacing, far more patients presented to clinic with painful total knee in which the patella had been resurfaced. The numerous pathologies requiring a treatment following patella resurfacing included patella loosening, fragmentation of the patella, avascular necrosis patella, late stress fracture, lateral facet pain, oblique resurfacing, and too thick of a patellar composite. In a large multi-center randomised clinical trial at 5 years from the United Kingdom in over 1700 knees from 34 centers and 116 surgeons, there was no difference in the Oxford Score, SF-12, EQ-5D, or need for further surgery or complications. The authors concluded, “We see no difference in any score, if there is a difference, it is too small to be of any clinical significance”. In a prospective randomised clinical trial performed at Tulane University over 20 years ago, no differences were observed in knee score, a functional patella questionnaire, or the incidence of anterior knee pain between resurfaced and unresurfaced patellae at time intervals of 2–4 years, 5–7 years, or greater than 10 years. Beyond 10 years the knee scores of total knee patients with a resurfaced patella had declined significantly greater than those with a non-resurfaced patella. There are numerous advantages of not resurfacing the patella including less surgical time, less expense, a lower risk of “major” complications (especially late complications), and if symptoms develop in an unresurfaced patella, it is an easier salvage situation with more options available. A small percentage of total knee patients will be symptomatic whether or not their patella is resurfaced. Not resurfacing the patella retains more options and has fewer complications. The major determinant of clinical result and the presence of anterior knee pain after knee replacement is surgical technique and component design not whether or not the patella is resurfaced. Patella resurfacing is occasionally necessary for patients with inflammatory arthritis, a deformed or maltracking patella, or symptoms and pathology that are virtually restricted to the patellofemoral joint. For the vast majority of patients, however, patella resurfacing is not necessary.

Tourniquet use in total knee arthroplasty (TKA) is convenient for the surgeon and provides a bloodless field for expeditious surgery and a dry field for cementation, but can best be described as an orthopaedic tradition. It is logical for complex anatomy of ligament, nerve, and vessel surgery but it may not be necessary for TKA. In one recent randomised trial, the absence of the tourniquet was not found to affect the quality of cement fixation. There are numerous potential downsides to the use of a tourniquet including decrease range of motion, delayed recovery, increased pain, wound complications, micro-emboli, neuropathy, and increased VTE. There are also a number of complications associated with the use of a tourniquet including arterial thrombosis, skin irritation below the tourniquet, post-operative hyperemia, blood loss, less accurate intra-operative assessment, and it complicates intravenous drug administration. Studies of range of motion have shown that when there is a difference noted, the range of motion is consistently better without tourniquet use. When a tourniquet is utilised it has been found to be advantageous to only use the tourniquet for a minimal amount of the case, typically when cementing is performed. Functional strength has also been found to be improved without the use of a tourniquet. In a recent randomised trial, tourniquet use was associated with decreased quad strength at 3 weeks that persisted at 3 months. This was attributed to muscle damage, tourniquet-induced ischemia, and compressive injury. Increased peri-operative pain has also been reported in randomised trials associated with the use of a tourniquet. Edema, swelling, and limb girth issues have also been noted to be associated with tourniquet use. Exsanguinating a limb will result in swelling approximately 10% of the original volume half due to a return of blood, and half due to reactive hyperemia. Longer tourniquet times are also associated with increased wound drainage and more wound hypoxia as measured by transcutaneous oxygen levels. Tourniquet use has also been associated with embolic phenomenon with several times greater risk of large emboli. In one study where quantitative MRI was utilised on both thighs after unilateral total knee replacement with and without a tourniquet, the tourniquet group showed more atrophy with a loss of 20% of the volume compared to the normal side in total knees performed with a tourniquet which also performed clinically worse. There is a small but substantial risk of arterial thrombosis particularly in patients that have atherosclerotic plaque. Ironically there is a risk of increased post-operative blood loss due to the post-tourniquet “blush” as the blood pressure and pain increase hours after a surgical procedure is completed. There is also difficulty in identifying and coagulating posterior and lateral geniculate vessels with the components in place. Utilizing a tourniquet also interferes with intra-operative assessment of patella tracking, range of motion, ligament stability, and gap balancing. Randomised clinical trials have concluded that there is less pain and quicker recovery without the use of a tourniquet. There have also been reports of less swelling, increased range of motion, less analgesic use and better clinical outcome when a tourniquet is not utilised. A meta-analysis of systematic reviews favored not utilizing a tourniquet due to the decrease in complication rate and the improvement in clinical results. While it is standard practice in the US to utilise a tourniquet, the strong consensus of the literature on the subject favors either not using a tourniquet or minimizing the use of a tourniquet for the period of time necessary for a very dry field for cement fixation.

In his classic monograph entitled Low Friction Arthroplasty of the Hip, which was published in 1979, John Charnley dedicated a chapter to thromboembolic complications. The overall incidence of pulmonary embolism (PE) was approximately 8% and the incidence of death from PE approximately 1%. Surveys of orthopaedic surgeons who undertake total joint replacement conducted by The American Association of Hip and Knee Surgeons (AAHKS), 30 years later, showed that there was still no consensus as to the best form of prophylaxis with a wide variation of methods being used.

In the past 3 years, for the first time there is uniformity in the recommendations of the American Academy of Orthopaedic Surgeons (AAOS) and the American College of Chest Physicians (ACCP). Both groups have reached an agreement that the rate of DVT formation is not the ideal endpoint to use when assessing the efficacy of thromboprophylaxis after joint replacement, as had been done in previous drug trials. Most of these DVTs are asymptomatic and of questionable clinical significance. At least one recent study brings into question the association between the rate of DVT formation and that of subsequent symptomatic events. Both groups also focus on minimizing iatrogenic bleeding complications, which can lead to compromised clinical results, including limited movement and pain in the case of knee replacement and increased risk of infection in both knee and hip replacement. To further complete the uniformity of approach in the United States, the Center for Medicare and Medicaid Services (CMS), which administers the Surgical Care Improvement Program (SCIP) that monitors hospital compliance with VTE prophylaxis of hospitalised patients, has also changed their policy. Beginning January 2014, either aspirin or a compression device has been considered as acceptable measures for THR, TKR and hip fracture. The remarkable success reported from many centers with the use of aspirin and/or the use of a mobile compression device in patients without major risk factors, such as a prior history of symptomatic VTE, clearly indicate that aggressive pharmacoprophylaxis is not necessary for the vast majority of patients who undergo joint replacement.

BACKGROUND

Patella resurfacing in TKA remains controversial. The purpose of this study was to compare the long-term clinical outcome in TKA in patients undergoing bilateral TKAs with one patella resurfaced and the other patella nonresurfaced.

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty.

A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were 18 years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began peri-operatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months post-operatively to document any evidence of deep venous thrombosis or pulmonary embolism.

Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (20 distal deep venous thromboses, 3 proximal deep venous thromboses, and 5 pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%.

Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provide a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature.

Total hip arthroplasty is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined the appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA.

The current generation metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify.

To generate data on the level of function of younger more active arthroplasty patients, a national multicenter survey was conducted by an independent university medical interviewing center with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centers throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. In another study of over 400 THA and SRA patients at two major academic centers, patients completed pain drawings that revealed an equivalent incidence of groin pain between THA and SRA, but an incidence of thigh pain in THA that was three times higher than in SRA in young active patients.

While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilization and investigation of this procedure.

The use of hard-on-hard bearings, including ceramics peaked in the mid 2000's and has seen rapid decline since that time. Ceramics are not new to the market place but have had a 40 year history outside the U.S. The basis for renewed enthusiasm for ceramics included improved manufacturing, improved taper tolerances, higher strength, and lower wear. In spite of the major improvements concerns have been expressed with new generation ceramics by the experts and thought leaders in the field. The major concerns included complications related to modularity, continued problems with fracture and consequences of fracture, limited surgical options, and squeaking and impingement. The conclusion of one review article was that “although ceramics show promise as a lower wear articulation, manufacturing and design modifications and improvements will continue in an attempt to address the substantial concerns that persist”. Modifications have indeed occurred. The question is rather all of these concerns have been addressed and the answer is no. One proposed solution was a hybrid material of Alumina and Zirconia (Delta Ceramic). The advantages included higher strength, lower wear, more options and possibly less squeaking. Unfortunately the modest material improvements did not begin to overcome the obstacles to adopting this technology. High on this list is the problem with cost with the current health care environment unwilling to pay for expensive new technology that does not have proven value. A 2nd major issue is new technology must account for variability in surgeon performance in maximising margin for error. The medical legal environment is unforgiving of failure of new unproven options. Most of the old issues with ceramics have not been completely resolved. Delta Ceramic in particular, has increased cost with no demonstrated benefit.

A major problem is there is no known problem with metal or ceramic against cross-linked polyethylene bearing in terms of wear or osteolysis in the 10–15 year time frame. Among all the bearing articulations, metal-on-cross-linked performs the best. The persistent vexing problems with ceramics include impingement, liner breakage, and squeaking. Ceramic components do not tolerate component malposition which increases wear and squeaking. The problem is that a substantial percentage of hip replacements are put in outside of the ideal radiographic zone even at specialty centers. Breakage continues to be a problem especially with liners. There is also a need for complete rim exposure for concentric placement with impaction of liners which makes ceramics less compatible with small incision surgery. The problem of squeaking has not been solved by Delta Ceramic. Originally a case report appeared in the literature of squeaking with Delta Ceramic. Since that time a large scale study has showed that only 69% of Delta Ceramic hips were silent with up to 13% being associated with reproducible squeaking.

While a new generation of ceramics are better than the earlier generation and have lowered the fracture risk and increased intraoperative options, the current generation ceramics still provide far fewer options than a standard metal-on-cross-linked total hip. The current generation metal-on-cross-linked total hips have 10–15 year results that cannot be improved upon in terms of wear and osteolysis. Other unsolved problems include breaking, chipping and squeaking. Ceramic-on-ceramic is less tolerant of suboptimal position which leads to impingement, edge loading, and an increased incidence of squeaking. Until all of these problems are successfully addressed, ceramic-on-ceramic cannot be advocated for widespread use.

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty.

A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism.

Of 3,060 patients, 28 (0.92%) had venous thromboembolism (20 distal deep venous thromboses, 3 proximal deep venous thromboses, and 5 pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%.

Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provide a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature.

The inability to consistently position components is associated with the major complications of hip replacement including instability, wear, liner breakage, limb length discrepancy, and limited function. This was a major catalyst for the demise of hard-on-hard bearings. The greatest challenge is accurate, reproducible positioning of acetabular component which is obtained in a surprisingly low percentage of cases. Other major issues include consistently obtaining proper limb length, offset, component sizing, and complete seating without fracture of either the acetabulum or the femur. There are two approaches to this issue; to either use virtual reality which applies technology that provides surrogates to direct visualization of components. The major issues with computer assisted techniques include questions of accuracy and increased time and cost. The other approach is to utilise intraoperative imaging which has been the gold standard traditionally, however, previously it has been a challenge to utilise intraoperative imaging without adding substantial time and cost. Historically intraoperative imaging has not been adopted because it disrupts work flow, the quality of images has been inadequate, and it has added too much additional time to allow for a series of repeat radiographs to be obtained.

Modifications of existing portable imaging that utilise direct radiography (DR plate technology) allow for intraoperative images that display within seconds. Imbedded software allows measurement of all parameters of interest. Three or 4 systems are currently in use, and this is not virtual reality but it is the gold standard. Advantages include higher quality images, faster service speed, minimal impact on OR work flow, eventual reduction in operating costs, elimination of processing of chemicals and film room/storage room, and most importantly the elimination of outliers and return to the operating room due to unexpected findings on recovery room radiographs.

Intraoperative imaging has been utilised at a number of centers in recent years and has led to numerous intraoperative changes to optimise component implantation in a surprisingly high percentage of cases. Advances in technology have made intraoperative digital imaging a practical feasible strategy to avoid outliers that increase complications and compromise results. The rapidly evolving technology makes this a very attractive option for optimising total hip component placement. In addition it is an excellent teaching tool that is rapidly embraced by residents and fellows and is an extremely effective in eliminating outliers.

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (CoCr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10 year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated CoCr stem. One study utilising pain drawings did establish that if a CoCr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involves removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the market place and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications.

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty.

A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began peri-operatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months post-operatively to document any evidence of deep venous thrombosis or pulmonary embolism.

Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thromboses, three proximal deep venous thromboses, and five pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%.

Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provide a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature.

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty.

A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism.

Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thromboses, three proximal deep venous thromboses, and five pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%.

Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provides a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature.

Wound complications are much more common following knee arthroplasty compared to hip arthroplasty. This is because of the precarious blood supply which contributes to the infection rate which is about twice as high. Many, if not most, infections are related to wound problems. Avoiding wound problems is a critical issue in joint replacement, more so in the knee than the hip. The volume of these procedures is growing rapidly. Infection continues to be a major complication. The incidence is not decreasing and infections are becoming more difficult to treat, because of resistant organisms. Also, the increasing number of procedures in patients with obesity and other risk factors makes wound management a major issue in knee replacement. Many wound problems are avoidable and can be minimised by care to detail by the surgeon.

Salvaging the problem wound is a major issue in total knee replacement currently in order to minimise infection, which remains a major issue and is frequently related to wound healing problems. The first step is identifying the patient at risk and either deferring surgery or optimising the patient to minimise the risk of wound healing problems and subsequent infection. Secondly, is appropriate soft tissue handling with careful attention to choosing the optimal skin incision. Third is taking steps to facilitate primary wound healing and absolutely minimising the risk of persistent drainage, particularly through the very judicious use of anticoagulants. Finally, the delayed wound healing and persistent drainage must be identified early and treated aggressively in order to minimise the risk of infection.

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (Co-Cr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10 year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated Co-Cr stem. One study utilising pain drawings did establish that if a Co-Cr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross-section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications.

TKA is among the fastest growing interventions in medicine, with procedure incidence increasing the most in younger patients. Global knee scores have a ceiling effect and do not capture the presence of difficulty or dissatisfaction with specific activities important to patients.

We quantified the degree of residual symptoms and specific functional deficits in young patients who had undergone TKA.

In a national multicenter study, we quantified the degree of residual symptoms and specific functional deficits in 661 young patients (mean age, 54 years; range, 19–60 years; 61% female) at 1 to 4 years after primary TKA.

To eliminate observer bias, satisfaction and function data were collected by an independent, third-party survey center with expertise in administering medical outcomes questionnaires.

Overall, 89% of patients were satisfied with their ability to perform normal daily living activities, and 91% were satisfied with their pain relief. After TKA, 66% of patients indicated their knees felt normal, 33% reported some degree of pain, 41% reported stiffness, 33% reported grinding/other noises, 33% reported swelling/tightness, 38% reported difficulty getting in and out of a car, 31% reported difficulty getting in and out of a chair, and 54% reported difficulty with stairs. After recovery, 47% reported complete absence of a limp and 50% had participated in their most preferred sport or recreational activity in the past 30 days.

When interviewed by an independent third party, about 1/3 of young patients reported residual symptoms and limitations after modern TKA. We recommend informing patients considering surgery about the high likelihood of residual symptoms and limitations after contemporary TKA, even when performed by experienced surgeons in high-volume centers, and taking specific steps to set patients’ expectations to a level that is likely to be met by the procedure as it now is performed.

The major causes of revision total knee are associated with some degree of bone loss. The missing bone must be accounted for to insure success of the revision procedure, to achieve flexion extension balance, restore the joint line to within a centimeter of its previous level, and to assure a proper sizing especially the anteroposterior diameter of the femoral component. In recent years, clinical practice has evolved over time with a general move away from a structural graft with an increase in utilisation of metal augments. Alternatives include cement with or without screw fixation, rarely, with the most common option being the use of metal wedges. With the recent availability of highly porous augments, the role of metal augmentation has increased. Bone graft is now predominantly used in particulate form for contained defects with more limited use of structural graft. The role of the allograft-prosthetic composite has become more limited. For the elderly with osteopenia and massive bone loss, complete metal substitution with an oncology prosthesis has become more common.

The degree of bone loss is a major determinant of the management strategy. For contained defects less than 5 mm, cement alone, with or without screw supplementation, may be adequate. For greater than 5 mm, morselised graft is frequently used. For uncontained defects of up to 15 mm or more, metal augmentation is the first choice. Bone graft techniques can be utilised in this setting, however, these are more time consuming and technically demanding with little demonstrated advantage. For larger, uncontained defects, newer generation highly porous augments and step wedges are useful. Large contained defects can be dealt with utilising impaction grafting, similar to the hip impaction grafting technique. Massive distal defects are expeditiously managed with oncology defects in the case of periprosthetic fracture and/or massive osteolysis particularly when combined with osteopenia in an elderly, low demand patient. Surgeons must be familiar with an array of techniques in order to effectively deal with the wide spectrum of bone defects encountered during revision total knee arthroplasty.

After decades of clinical experience and hundreds of studies, the ideal method of deep vein thrombosis (DVT) prophylaxis remains controversial. One of the most widely quoted publications on the subject in recent years has been the guidelines published by the American College of Chest Physicians (ACCP). The seventh and eighth ACCP Conference on Antithrombotic Therapy and Prevention of Thrombosis were published in Chest in 2004 and 2008 respectively. The highest level recommendation (1-A) was reserved for Warfarin at a relatively high dose (target international normalised ratio (INR) of 2–3), Low Molecular Weight Heparin (LMWH), or Fondaparinux for a minimum of 10 days for both total hip and total knee replacement. These agents were recommended for all patients, regardless of their relative risk of bleeding or risk of venous thromboembolism (VTE). These recommendations were found to be aggressive by the standards of most orthopaedic surgeons and a number of issues were identified with the methodology and resulting recommendations of the ACCP including: The emphasis on multicentre randomised clinical trials that are enormously expensive and strongly weighted towards pharmaceutical sponsored studies, methodology that prevented inclusion of studies of lower cost, lower tech options such as aspirin or lower dose Warfarin since randomised trials on a large scale are not available due to lack of funding or pharmaceutical company interest in generic low-cost options, lack of consideration of pneumatic compression options such as newly available mobile foot pumps with chips for monitoring compliance, financial conflict of interest of virtually all of the authors of the guidelines and the fundamental problem with utilising asymptomatic DVT as a study endpoint. The concerns with the aggressive nature of these recommendations were confirmed by studies from two academic centres which reported a high incidence of wound and bleeding complications when changing to a 1-A protocol. Recent studies indicate that readmissions following joint replacement are much more likely to be due to wound drainage and bleeding complications than DVT or pulmonary embolism (PE). In response to these concerns, the AAOS released guidelines in 2008 that were updated in 2011. The resulting recommendations represented a dramatic departure from the ACCP guidelines. Clinically crucial endpoints such as PE and death were utilized in the analysis rather than asymptomatic DVT, which was the criteria utilised by the Chest Physicians and the 2011 recommendations also considered symptomatic DVT. The AAOS guidelines consider patient risk category rather than making a uniform recommendation for all patients. Much more discretion is given to surgeons to utilise less aggressive prophylactic strategies including aspirin and foot pumps.

In 2012, the ninth edition of the ACCP guidelines was published and many of the concerns previously expressed over prior editions were successfully addressed. Conflict of interest among the authors was much less of an issue, there was more attention placed on symptomatic events and clinically important complications, and a wider scope of literature was considered. The resulting guidelines represented a dramatic departure from previous recommendations. Aspirin and pneumatic compression were elevated to level 1 recommendation status along with potent drug regimens such as injectable drugs (LMWH and Xa inhibitor) as well as the new oral Xa inhibitors and antithrombin agents. When pneumatic compression devices are utilised, the use of a battery powered device capable of recording compliance was recommended. Patient risk status as well as patient preference were also considered. The new ACCP guidelines have successfully addressed many of the concerns previously addressed and are much more in line with the AAOS guidelines. It is anticipated that the federal Surgical Care Improvement Project (SCIP) guidelines for VTE prophylaxis will be released in 2013 and will also embrace the changes recommended by the ACCP. It is further likely that the AAOS and ACCP guidelines are close enough that they may well join forces in the near future and release a single unified document.

Total hip arthroplasty is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined the appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA.

The current generation of metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify.

To generate data on the level of function of younger more active arthroplasty patients, a national multicentre survey was conducted by an independent university medical interviewing centre with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centres throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances.

While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilisation and investigation of this procedure.

Introduction: Third generation fixation systems allow for the retightening of cables, and are associated with high rates of trochanteric union. This is a prospective study undertaken to evaluate the outcome of the first 40 patients treated with a third generation cable plate and trochanteric hook system.

Methods: 36 patients treated by two revision hip arthroplasty surgeons using a third generation cable plate system were enrolled and followed up. These included 28 females and 12 males with an average age of 64 (range: 48–91). Large hooks were used in 30 with an average of 4.8 cables (range: 4–9). The need to retighten cables intra-operatively was noted. Clinical and radiographic follow-up was undertaken at 2 years.

Results: A third generation fixation system was used for 16 peri-prosthetic fractures, 6 trochanteric non unions, 5 structural femoral allografts, 6 complex revisions and for trochanteric advancement in 3 cases. The first cable tightened was loose by the end of the procedure in the majority of cases and had to be retightened. There were no cases of fretting or cable breakage. Two further tro-chanteric non unions needed re-fixation and bone grafting in a further procedure

Discussion and Conclusion: Third generation cable system allow for re-tightening, as the cable is not damaged by the crimping mechanism. This facility appears critical as some retightening is invariably required in the process of applying this type of device. There were only 2 re-operations for trochanteric non unions, but the overall outcomes were otherwise excellent, with no fretting or cable breakage. Modern cable systems afford improved, more flexible trochanteric fixation possibilities.

Serological tests including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are frequently used in the preoperative workup to screen for periprosthetic infection (PPI) in total hip arthroplasty (THA). The cut-off points reported in the literature are arbitrarily chosen by investigators. Similarly, the values used in laboratories to distinguish elevated results vary from one institute to another. Therefore, we intended to define the appropriate cut-off points of ESR and CRP that can be used to differentiate infection from aseptic failure of THA.

A review of our joint registry database revealed that 515 THA revisions (131 infected cases) were performed during 2000–2005. Intraoperative samples for culture were taken in all cases. The criteria used for diagnosis of infection were a positive intraoperative culture on solid media, presence of an abscess or sinus tract that communicated with the joint, positive preoperative aspiration culture, and/or elevated fluid cell count and neutrophil differential of the aspirated fluid. Non-infected patients with confounding factors that can elevate ESR and CRP including collagen vascular disease, inflammatory arthropathy, malignancy, and urinary tract infection were excluded. Receiver operator curves were used to determine the ideal cut-off point for both ESR and CRP.

The mean value of ESR in the infected group (77mm/ hr) was significantly higher compared to that of the non-infected cohort (29mm/hr) (p=0.0001). Similarly, infected patients presented with a greater mean CRP (9.8 mg/dl) than their non-infected cohort (1.48 mg/ dl) (p=0.0001). The infection threshold for ESR was 45mm/hr with a sensitivity of 85% and specificity of 79%, while the optimal cut-off value for CRP was defined as 1.6 mg/dl which yielded a sensitivity of 86% and specificity of 83%.

The optimal threshold values we determined are higher than the arbitrarily chosen values cited in the literature for ESR (30mm/hr) and CRP (1mg/dl). Although it has been previously reported that the sensitivity and specificity of CRP are far greater than that of ESR, we found that the two tests have comparable diagnostic value.

One of the routinely used intraoperative tests for diagnosis of periprosthetic infection (PPI) is Gram stain that is reported to carry a very high specificity and a poor sensitivity. However, it is not known if the result of this test can vary according to the type of joint affected or the number of specimen samples collected. This study intended to examine the role of this diagnostic test in a large cohort of patients from single institution.

A review of our joint registry database revealed that 453 total knee arthroplasty (TKA) and 551 total hip arthroplasty (THA) of which 171 and 150 cases were respectively infected underwent revision surgery during 2000–2005 and had intraoperative cultures available for interpretation. A positive gram stain was defined as the visualisation of bacterial cells or ‘many leukocytes’ (> 5 per high power field) under the smear. The sensitivity, specificity, and predictive values of each individual diagnostic arm of Gram stain were determined. Combinations were performed in series that require both tests to be positive to confirm infection and in parallel that necessitate both tests to be negative to rule out infection. This analysis was performed for THA and TKA separately and later compared for each joint type.

The presence of organism cells and ‘many’ neutrophils on a Gram smear had high specificity (98%–100%) and positive predictive value (89%–100%) in both THA and TKA. The sensitivities (30%–50%) and negative predictive values (70%–79%) of the two tests were low as expected among both joint types. When the two tests were combined in series the specificity and positive predictive value were absolute (100%). The sensitivity (43%–64%) and the negative predictive value (82%) improved among both THA and TKA.

The presence of organisms or ‘many’ leukocytes on the Gram smear can confirm PPI in TJA. As expected, the sensitivity and negative predictive value of the two tests were low, and therefore infection could not be safely ruled out. Although the two diagnostic arms of Gram stain can be combined to achieve improved negative predictive value (82%), Gram stain continues to have poor value in ruling out PPI. With the advances in the field of molecular biology, novel diagnostic modalities need to be designed that can replace these traditional and poor tests.

Introduction: Intraoperative tissue culture remains the “gold standard” in diagnosing periprosthetic infection (PPI). However, an organism is not always cultured and this has been attributed to the fact that preoperative antibiotics were administered. This study intends to examine if preoperative antibiotics prevent isolation of intraoperative organisms.

Methods: 91 total joint arthroplasty patients diagnosed with PPI during (1999–2005) and who had positive aspiration culture were included in the study. All intravenous antibiotics that were given to the patient within seven days of surgery were documented. The total number of positive intraoperative fluid and tissue samples of patients who did and did not receive antibiotics was calculated. Susceptibility of the organism(s) to antibiotics was determined by antibiogram of the preoperative and intraoperative culture.

Results: 60 out of 91 patients received preoperative antibiotics within seven days of surgery. Antibiotics prevented isolation of an intraoperative organism in 6 out of the 60 (10%) cases. All of the 31 patients who did not receive any preoperative antibiotics had positive intraoperative cultures. Chi-square analysis revealed no significant difference between giving preoperative antibiotics within 7 days and isolating an intraoperative organism (p=0.068). Giving antibiotics that specifically targets the culprit organism did not significantly affect the fluid (p=0.585) or tissue culture yield (p=0.152) either.

Discussion: Although, giving preoperative antibiotics can prevent isolation of intraoperative organisms in 10% of cases, this is not statistically or clinically significant in patients with positive aspiration cultures because the organism is known beforehand. However, it is clinically and medicolegally relevant to withhold antibiotics in patients with negative aspiration cultures since the postoperative treatment antibiotic is tailored according to the organism cultured.

Purpose: Problem : Infection in TKA is a devastating yet common complication. 2-stage reimplant procedures are performed in the treatment of this condition. Purpose:To evaluate the clinical, radiographic, complications, and patient satisfaction results of 2nd stage reimplantation revision TKA with the use of a TTO. Technical aspects of TTO length, fixation, bypass, and complications are reported.

Methods: From 1996–2004 our database identified 25 revision TKA (12% of 206 revision TKA) performed using a TTO. In 20/25 cases the procedure was a 2nd stage reimplant. Demographics, infecting organism, Gustillo grade, clinical, radiographic, AORI defects, complications, patient satisfaction were evaluated prospectively. All patients were followed until radiographic union of the TTO.

Results: At a mean follow up of 22 mo(range,6–84) no patients were lost to follow-up. 24 (96%)TTO’s healed - 1 requiring revision ORIF. Prior to reimplantation, patients had undergone a mean of 3.3 prior knee surgeries(range,2–8). Prior extensor mechanism procedures had been performed in 43% of knees. Methicillin resistant staphylococcus was the infecting organism in > 50% of knees. 19 knees had a static cement spacer removed at revision. Time to 2nd stage reimplant was 39 weeks(range,15–68). Poor preop range of motion and stiffness (mean arc 430 , range 10–950) improved significantly postop (mean flexion 880 p< .05). 13 (56%) knees required an adjunctive extensor procedure at the time of TTO. TTO length averaged 8.8cm(range,8–10). Screws(15 knees), 2mm cables(6), wires(4) were used for TTO fixation. Mean stem bypass of the TTO was 63mm (−20 to 100). 21 (84%) patients were satisfied with the procedure, despite 8 knees(32%) requiring further surgery. 6 (24%) TTO complications occurred; 1 escape requiring fixation. All TTO’s had healed at recent follow up.

Conclusions: TTO is a useful procedure for exposure in 2nd stage revision TKA. TTO union is predictable(96%), despite technical complications. Recurrence of infection requiring further surgery did not compromise TTO results. Prior/concurrent extensor mechanism procedures were noted frequently.

Funding : Other Education Grant

Funding Parties : Wright Medical Technologies

Introduction and Aims: The use of porous coated femoral stems in revision hip arthroplasty has been associated with a high rate of complications including femoral fracture, femoral perforation and eccentric reaming. The purpose is to determine if using a distally slotted-fluted femoral stem is associated with lower incidence of the above three intra-operative complications.

Method: The intra-operative complications of 175 cementless revision total hip arthropasties (THA) using a distally slotted-fluted femoral stem were reviewed. Three categories of complications were recorded: femoral fracture, femoral perforation and eccentric reaming. Radiographic evaluation was based on standard antero-posterior and lateral views of the hip joint performed in the intra-operative or immediate post-operative period. Statistical analysis for factors associated with complications was performed using the chi-square test.

Results: Intra-operative complications occurred in 16 patients (9.1%). There was no statistically significant association between complication rate and type of surgical approach, stem length, stem diameter, or host bone quality. The complication rate was significantly lower than the 44% total complication rate previously reported utilising a long, solid, extensively coated revision stem without a slot or flute (p< .01). These results are consistent with laboratory testing, which revealed significantly lower bone strains at the isthmus when inserting a long cementless revision stem with a slot and flute compared to a solid fully coated stem of identical geometry.

Conclusion: The use of a distally slotted fluted porous coated femoral stem in revision hip arthroplasty results in a dramatically lower complication rate compared to rates previously reported for solid porous stems. These results strongly support the continued use of such a prosthesis for revision THA.

We examined 108 uncemented femoral stems with modular femoral heads which had been retrieved for reasons other than loosening. There were detectable amounts of wear and corrosion in 10 of 29 (34.5%) mixed-alloy components and 7 of 79 (9%) single-alloy components after a mean implantation time of 25 months. We found no correlation between the presence or extent of corrosion or surface damage and any of time in situ, initial diagnosis, reason for removal, age, or weight. Stems with wear and corrosion were less likely to show histological bony ingrowth. The interface between the head and stem of modular total hip components is a possible source of ion release and wear debris, but wear and corrosion were totally absent in most specimens. This suggests that this problem could be avoided, and that further research is required to develop manufacturing methods which would minimise such changes.

We report complications from the use of modular components in 20 hip replacements in 18 patients. Fifteen complications (in 13 patients) were related to failure of a modular interface after operation. Femoral head detachment from its trunnion was seen in 6 hips from trauma (3), reduction of a dislocation (2), and normal activity (1). In one case the base of the trunnion fractured below an extra-long modular head. In seven other hips the modular polyethylene liner dislodged from its shell, causing severe damage to the shell in four cases with extensive metallosis. In one other hip an asymmetrical polyethylene liner rotated, resulting in impingement of the femoral component and recurrent dislocation. Operative errors were seen in five cases: implantation of a trial acetabular component in one; and mismatching between the size of the femoral head and the acetabular component in the others. Surgeons who use hip replacements with modular components should be aware of the potential for operative error and of the importance of early treatment for postoperative mechanical failure.

Six porous-coated, uncemented femoral components were revised at a mean of 34.5 months for persistent thigh pain. At operation the stems were rigidly stable, difficult to extract, and showed good bony ingrowth. The four men and two women, with an average age of 59 years, all had thigh pain starting within the first year, progressive over time and unresponsive to conservative measures. These cases show that rigid fixation with good bony ingrowth does not guarantee the clinical success of a porous-coated uncemented femoral stem.

To assess the effect of improved methods of femoral cementing on the loosening rates in young patients, we reviewed 50 'second-generation' cemented hip arthroplasties in 44 patients aged 50 years or less. The femoral stems were all collared and rectangular in cross-section with rounded corners. The cement was delivered by a gun into a medullary canal occluded distally with a cement plug. A clinical and radiographic review was undertaken at an average of 12 years (10 to 14.8) and no patient was lost to follow-up. No femoral component was revised for aseptic loosening, and only one stem was definitely loose by radiographic criteria. By contrast, 11 patients had undergone revision for symptomatic aseptic loosening of the acetabular component and 11 more had radiographic signs of acetabular loosening.

A study was undertaken to determine whether a significantly different clinical outcome could be expected following nonoperative treatment of acute partial anterior cruciate ligament (ACL) tears from that of complete tears. A detailed follow-up of 107 patients with arthroscopically confirmed tears was obtained; 72 were complete tears and 35 partial. The overall results in those with partial tears were 23% excellent, 29% good, 17% fair, and 31% poor; with complete tears the results were 11% excellent, 20% good, 15% fair, and 54% poor. The patients with partial tears had a lower incidence of associated meniscal tears, needed fewer reconstructions and more of them returned to sport than those with complete tears.

Recent clinical studies have suggested that a neurological lesion may be a cause of adolescent idiopathic scoliosis and animal experiments have implicated the posterior column pathway. We have tried to determine if differences in neurological response could be detected and measured clinically, and have compared the threshold of detection of vibratory sensation in 20 girls with adolescent idiopathic scoliosis with that in 20 clinically normal age-matched controls. A highly significant reduction of the threshold of detection of vibration was seen in the scoliotic group compared to the controls (p less than 0.001). Curve magnitude did not correlate with this threshold for either the upper (r = 0.172) or lower extremity (r = 0.126). Significant asymmetry between right- and left-sided thresholds to vibration was demonstrated in the scoliotic group. Our study supports the concept that an aberration in the function of the posterior column pathway of the cord may be of primary importance in the aetiology of idiopathic scoliosis. A clinically practical test to measure this function is presented.