Introduction: Several types of “ Total Joint Regeneration System” were proposed where wide defect of cartilage expected to be regenerated under proper mechanical environment. Several types of therapeutic equipments for the Total Joint Regeneration System were designed and animal trial for the system was performed. Fundamental experiment evaluating cartilage generation under continuous sliding motion is also reported. Material and methods: Three Japanese white rabbits (male, 12~15 weeks-old) weighing 3.0& #13199; and one beagle dog (male) weighing 15& #13199; were used for the trial operation for the Total Joint Regeneration System. A large full-thickness defect of the articular cartilage was made on both knees. And Internal-support type device was fixed to the knee of one side. The device is consisting of 2 parts (the screw and the T-bar). The screw was fixed in tibia from the fore part of ACL attachment to anterior part of the tibia. The rod of the T-bar was inserted into the inner hole of the screw. The upper part of the T-bar hold the femoral intercondyle and keep the regenerated portion in non-weight-bearing condition. Regeneration at the osteochondral defect was evaluated at 4 weeks postoperatively. [Cartilage generation by continuous sliding motion] A coccygeal vertebra of F344 rats (7weeks-old) was osteot-omized, and the distal part of the vertebrae was moved continuously in sliding motion using mobile external fixation. Results and discussion: Walking conditions were comparatively good in all animals. Macroscopic observation shows better appearance of defected area in the supported side, however the apparent histological difference between control side and internal-support side could not be recognized in the rabbits cases because of inappropriate fitting of the devices. Hyaline cartilage tissue with better metachromatic matrix with safranin-O staining was observed on the supported side of dog knee. Result of fundamental experiment also showed the importance of setting mechanical environment where hyaline cartilage with layer structure similar to normal articular cartilage was produced by controlled sliding motion. We are now improving the design of the Total Joint Regeneration System refering to those results

Introduction. The obesity epidemic is a growing problem and must be considered with the projected increased demand for total hip arthroplasty (THA). Previous studies have reported increased complication rates after THA in the obese population, which has led to hesitation in offering surgery to this population. Moreover, some insurers are denying coverage for morbidly obese patients. While many consider obesity a “modifiable” risk factor, very few patients with advanced osteoarthritis have successfully lost substantial weight. The experience of centers that utilize systematic preoperative risk stratification tools and standardized postoperative total joint pathways may be underrepresented in prior studies. The aim of this study is to describe one surgeon's experience performing THA in morbidly and super-obese patient populations using an institutional preoperative Risk Stratification Tool (RST) and total joints pathway. Methods. We conducted a retrospective review of patients undergoing primary THA between May 2014 and December 2017 performed by a single surgeon at a tertiary care referral center. All patients were assessed preoperatively using an institutional RST and had a minimum of 90-day postoperative follow up. Patients were stratified by body mass index (BMI, kg/m. 2. ): non-obese (BMI < 30), obese (30–34), severely obese (35–39), morbidly obese (40–44), and super-obese (≥ 45). Primary outcomes were inpatient and 90-day complications. Continuous and binary parameters were analyzed by Kruskal-Wallis and Fisher exact tests. Logistic regression was additionally utilized to evaluate outcomes by BMI cohort. Results. A consecutive series of 368 patients met inclusion criteria across all BMI cohorts. There was significant variation with respect to age (P=0.001), BMI (P<0.001), diabetes (P=0.008), ASA class (P<0.001), and anesthesia type (P=0.003) (Table 1). Variation among BMI cohorts was also identified for several operative and postoperative parameters, including longer operative and in-room time and greater length of stay (P<0.001) (Table 2). Compared to non-obese patients, super-obese patients had 20.1 greater odds of return to OR within 90 days for superficial surgical site infection (SSI) or prolonged round drainage (P=0.008) (Table 3). Notably, morbidly and super-obese patients were not at significantly increased risk for inpatient intensive care unit (ICU) transfer, blood transfusion, 90-day emergency room visit, or 90-day readmission compared to their non-obese counterparts. For patients in whom 1-year follow-up was available, these differences between BMI cohorts remained insignificant. Conclusions. Patients with BMI>40 are more likely than non-obese patients to have increased postoperative rehabilitation needs but are not at increased risk for in-hospital complications. Super-obese patients have greater risk of superficial SSI or prolonged wound drainage than non-obese patients but are not at increased risk for revision or deep infection in any cohort. Use of a preoperative RST may help to mitigate postoperative complications and readmissions previously associated with morbid and super-obesity. We conclude that THA can be safely performed in super-obese patients and therefore care should not be denied to this population. Summary sentence. Total hip arthroplasty (THA) can be safely performed in morbidly and super-obese patients with the use of a preoperative risk stratification tool (RST) and total joints pathway. For any tables or figures, please contact the authors directly

Aims

Endoprosthetic reconstruction with a distal femoral arthroplasty (DFA) can be used to treat distal femoral bone loss from oncological and non-oncological causes. This study reports the short-term implant survivorship, complications, and risk factors for patients who underwent DFA for non-neoplastic indications.

Major long-term complication of total hips is osteolysis in the more active patients. Osteolysis is a result of the biological response to the wear debris particles. This has resulted in the search for improved bearings such as metal and ceramic on polyethylene, all ceramic, and all metal total hips. Wear ranking of metal-polyethylene, ceramic-polyethylene, metal-metal, and ceramic-ceramic total hips has become clear at ratios of 1,000:500:10:1. However, wear debris from polyethylene, ceramic, and metal wear tests average about 0.6, 0.3, and 0.02 microns, respectively. From this information we can now deduce the number of particles librated is millions for ceramics, billions for polyethylene, and trillions for metal. In recent years, studies have revealed new information on the biological response to various types of wear debris. Factors such as number of particles, particle morphology (size and shape), and surface to volume ratio are becoming keys to a partial comprehension of this biological response and osteolysis. Recent studies have demonstrated that smaller particles (< 0.1 microns) may be more toxic to cells than larger particles (> 0.1 microns). Studies have shown that crosslinking of polyethylene reduces the size of the wear debris particles and that for gamma irradiated polyethylene this reduction in size is proportional to the radiation dose. It has also been shown that crosslinking results in a significant reduction in fibril particles. Therefore, large reductions in wear rate do not necessarily mean that the total joint will be more successful. Thus, two factors, which interact, are the volume rate of wear and the morphology of the wear debris particles. Some investigators have developed a biological ind

Objectives

Biologic agents (BIO) drastically changed the rheumatoid arthritis (RA) therapy from starting to use biologics at 2003 in Japan. The rate of orthopaedic surgery, especially total joint arthroplasty (TJA) may reflect trends in disease severity, management and health outcomes.

The purpose of this study was to establish whether retransfusion of blood collected in drains following total joint replacement was a safe and effective procedure. All patients undergoing a total joint arthroplasty, with no history of infection, between March and October 2001, were entered into the study. A single surgeon operated on all patients and no patient was excluded from the study. Informed consent was obtained and all blood drained into a recollection system within 6 hours of surgery was retransfused .A prospective protocol was filled out in all cases documenting the pre and postoperative haemoglobin, amount transfused and any extra transfusion requirements. A special note was made of any complications encountered during retransfusion. The results were then compared to previously known transfusion rates within the same hospitals. There were 141 Total Joint Arthroplasties performed within the study period -12 were bilateral and 12 were revisions procedures. The average drainage was 655ml (60–3280ml) and the average amount of retransfused blood from the drains was 225ml (100–1822ml). There were a total of 9 (6.3%) subsequent blood transfusions. Four (3.8%) in primary and 5 (20.8%) in bilateral or revision procedures. Transfusing patients with salvaged blood from the drains in total joint arthroplasty is a safe, reliable and cost effective practice, which significantly reduces the requirement for a subsequent blood transfusion. As a result of this study the Christchurch Orthopaedic Group has adopted a routine practise of retransfusing drained blood in all total joint arthroplasties

Venous thromboembolism (VTE) remains an immediate threat to patients following total hip and knee replacement. While there is a strong consensus that steps should be taken to minimise the risk to patients by utilising some forms of prophylaxis for the vast majority of patients, the methods utilised have been extremely variable. Clinical practice guidelines (CPGs) have been published by various professional organisations for over 25 years to provide recommendations to standardise VTE prophylaxis. Historically, these recommendations have varied widely depending in underlying assumptions, goals, and methodology of the various groups. This effort has previously been exemplified by the American College of Chest Physicians (ACCP) and the American Academy of Orthopaedic Surgeons (AAOS). The former group of medical specialists targeted minimising venographically proven deep vein thrombosis (DVT) (the vast majority of which are asymptomatic) as their primary goal prior to 2012. The latter group of surgeons targeted minimising symptomatic VTE. As a result prior to 2012, the recommendations of the two groups were widely divergent. In the past year, both groups have reassessed the current literature with the principal goals of minimising symptomatic VTE events and bleeding complications. As a result, for the first time the CPGs of these two major subspecialty organisations are in close agreement.

Background

The ability to identify those at risk for longer inpatient stay helps providers with postoperative planning and patient expectations. Decreasing length of stay in the future will be determined by appropriate patient selection, risk stratification, and pre-operative patient optimization. The purpose of this study was to identify factors that place patients at risk for extended postoperative lengths of stay.

Introduction

Wear debris and metal ions originating from metal on metal hip replacements have been widely shown to recruit and activate macrophages. These cells secrete chemokines and pro-inflammatory cytokines that lead to an adverse local tissue reaction (ALTR), frequently requiring early revision. The mechanism for this response is still poorly understood. It is well documented that cobalt gives rise to apoptosis, necrosis and reactive oxygen species generation. Additionally, cobalt stimulates T cell migration, although the effect on macrophage motility remains unknown. This study tests the hypothesis that cobalt ions and nanoparticles affect macrophage migration stimulating an ALTR.

Introduction

Metal on metal (MoM) bearings have been dealt a severe blow in the past few years. The release of metal ions may have arisen from corrosion, wear, or a combination of the two. Edge loading due to implant malposition is thought to cause a failure of lubrication and to contribute to excessive wear and increased metal ion release [1]. Literature reports aseptic lymphocytic vasculitis-associated lesions (ALVAL) are associated with a variety of failures which occur to some degree in all implanted metal femoral components [2, 3]. Moreover, Willert et al [4] has described ALVAL in non-MoM bearing designs too. This paper has investigated the metal ion release due to total hip replacement (THR), Hip Resurfacing (HR) and total knee replacement (TKR).

Background

Infection is one of the most severe comlications of the total arthroplasty. We sometimes encounter cases, which are very hard to finish repeated recurrence. Usage of steroids, immunosuppressants, and biologics would possibly effect to the incidence of the prosthetic infection and to the result of its treatment. Biologics have drastically decreased the number of the total arthoplasic patients, on the other hand, we must be more careful about the infectious conditions. For the infection two stage revision surgery; first removal and antibiotics cement spacer insertion then reimplantation later; is often chosen but sometimes one time antibiotics cement spacer cannot stop the infection and requires multi times spacer insertion. In those cases the dead spaces, poor blood supply and tight skin could be the cause of the recurrence. For these cases we had been performing musclo-cutaneal flap and successfully finish the infection.

Our aim was to analyse the influence of the size, shape and number of particles on the pathogenesis of osteolysis. We obtained peri-implant tissues from 18 patients having revision surgery for aseptically loosened Freeman total knee replacements (10), Charnley total hip replacements (3) and Imperial College/London Hospital double-cup surface hip replacements (5). The size and shape of the polyethylene particles were characterised using SEM and their concentration was calculated. The results were analysed with reference to the presence of radiological osteolysis.

The concentration of polyethylene particles in 6 areas with osteolysis was significantly higher than that in 12 areas without osteolysis. There were no significant differences between the size and shape of the particles in these two groups.

We conclude that the most critical factor in the pathogenesis of osteolysis is the concentration of polyethylene particles accumulated in the tissue.

Summary

Prosthetic UHMWPE added with vitamin E and crosslinked UHMWPE are able to decrease significantly the adhesion of various bacterial and fungal strains limiting biomaterial associated infection and consequent implant failure.

Prevention of surgical infection following joint arthroplasty is preferable to treatment.

Prevention requires identification and control of the potential sources of microbial contamination. The purpose of this study was to determine whether the density of airborne particulate in the operating room during total joint arthroplasty could predict the density of viable airborne bacteria at the surgery site.

A standard particle analyzer was used to measure the number and diameters of airborne particulate during 22 joint arthroplasty surgeries performed in non-laminer flow rooms. An impact air sampler and standard culture plates were used to collect airborne particulate and were analysed to identify and count colony-forming units.

Particulate density averaged > 500,000 particles/ft3, and 1,786 colony-forming units were identified, primarily gram-positive cocci. The density of particles ≥10um explained 41% of the variation in colony-forming unit density. Colony-forming units and ≥10 um particle density increased with longer surgery duration and higher staff counts.

This is the first study to the authors knowledge that shows a correlation between the number of persons in the OR and CFUs at the surgical site during total joint arthroplasty procedures. Increasing surgical staff appear to produce both more particulate and more CFUs. These observations support the use of environmental controls that isolate and protect the surgical site from airborne particulate and microbial contamination.

Continuous monitering of particulate larger than 10 um during joint arthroplasty procedures may be warrented.

Introduction: Chronic infection after total joint arthroplasty is a complication of major concern to orthopaedic surgeons, especially if patients suffer from any type of immunodeficiency. But for extensive surgical and systemic treatment recurrence rates are high.

Silver is a long known local antimicrobial agent. The use of silver coated prostheses is a valuable option in some cases.

Yet there are patients for whom the permanent implantation of large amounts of silver does not seem to be the perfect solution.

Methods: From 02/2004 to 12/2005 nine patients with severe deep infections after multiple revisions following total joint replacement underwent two-stage revision and implantation of silver coated megaendoprostheses (MUTARS®).

From 04/2004 to 01/2006 seventeen patients of slightly less impaired disposition were treated by a comparable two-stage procedure using silver-augmented cemented spacer prostheses or cement fills.

Patients are closely observed regarding toxic side effects.

Concentration of silver in blood and puncture samples are measured using an argon plasma mass spectrometer.

Results: To date eight of nine patients with silver coated megaendoprostheses are free of infection. One patient with known cellular and humoral immunodeficiency recently developed a fistula, puncture showing superinfection by coag. neg. staphylococci.

In the second group one patient of seventeen actually shows a persisting infection, but cannot be matched properly as he primarily suffered from a long-term infected knee arthrodesis.

Silver concentrations ranged from a maximum of 1010 to 243 μg/kg (ppb) to a minimum of 84 to 304 μg/kg (ppb) with silver coating, and a maximum of 380 to 22,9 μg/kg (ppb) to a minimum of 76 to 5,02 μg/kg (ppb) with silver spacers.

There are large individual differences in both groups.

We found no signs of argyrosis or recently developed neurological deficits.

Discussion: The use of silver in the treatment of severely infected joint prostheses is a promising approach, but it is not without risks and throwbacks. Strict indication and surveillance are needed to keep possible side effects under control. It ought not to be used out of specialized centres.

Ultra-high molecular weight polyethylene (UHMWPE) has been used for the bearing liner or inlay components in total joint replacements such as total hip, knee, and artificial disk since 1960’s. UHMWPE components generate wear debris during articulation, which play a key role in osteolysis, subsequent aseptic loosening, and eventually revision surgery. Efforts to solve the wear problem in UHMWPE and to quantify the amount of wear have driven many studies. But in vivo radiographic penetration depth measurement is the result of both wear and viscoelastic creep. Previous study reported that over 70% of the dimensional changes in UHMWPE acetabular cups were due to creep. Creep deformation was quantified under the static and dynamic compressive pressures (2, 4, 8Mpa) that are clinically relevant for the hip joint loads in normal motions. However, according to the finite element stress analyses in UHMWPE components under the active motions in hip, knee, and artificial disk replacements, very high level of contact pressures locally ranged from under 10MPa up to over 60Mpa. In this study, we quantified the creep of UHMWPE under the several high levels of dynamic compressive pressures and compared the results from the previous results.

For creep tests, UHMWPE rectangular blocks (10mm long, 10mm wide, 8mm thick) were manufactured from molded unirradiated Chirulen^® 1020 sheet (MediTECH, Deutchland). MTS 858 hydraulic test machine was used for conducting the dynamic compressive creep tests under the four different sinusoidal (1Hz) maximum pressures of 10, 20, 40, and 60MPa and minimum pressures of 1, 2, 4, and 6MPa, respectively. All tests were conducted for a total duration of 4×103 minutes at ambient conditions. During the test the displacements of crosshead were stored and the changes in thickness of block specimen devided by the initial thickness were calculated to get the creep strain.

The mean dynamic compressive creep strain increased as the loading time increased and had a linear relationship (R2=0.96) with the logarithmic scale of time for all maximun pressures. Over 90% of total creep strain occurred within the first 103 minutes. The rates of creep strain (slopes of curve fitting in logarithmic scale of time) for each maximum pressure were listed in Table 1 with the rates of creep strain for low maximum pressures from the previous study [3]. The rates of creep strain increased linearly as the maximum pressure increased for both current study (R2=0.96) and previous study (R2=0.99). The slope of linearity for the current study with high levels of contact pressures was a little larger than that for the previous study with low levels of contact pressures. This difference in the slope of linearity between current and previous studies lies in the creep recovery during measurement of specimen thickness by micrometer in the previous study. Neglecting this difference, the results of current study can be extrapolated to anticipate the creep strain of UHMWPE under the dynamic compression for the low levels of contact pressures.

This study investigated the relationship between histological, clinical and radiological features of aseptically loose total joint replacements (TJRs) and synovial fluid levels of interleukin (IL)-1b, IL-6, IL-8 and IL-10.

Tissue and synovial fluid samples were retrieved from patients undergoing primary (hip; n=15: knee; n=13), or revision of aseptically loose TJRs (hip; n=14: knee; n=9). The presence of inflammatory cells, blood vessels and wear debris in the tissue were assessed on a relative scale. Revision TJRs were assessed for sepsis, migration of the implant, gross loosening and the degree of radiolucency. Cytokine levels in the synovial fluid samples were determined by ELISA.

All cytokines were increased in synovial fluid from revision TJRs compared to primary replacements, as were the degree of macrophage and giant cell infiltration (p< 0.01). There was a significant positive correlation between the presence of macrophages and giant cells with the levels of IL-1b, IL-8 and IL-10 (p< 0.05) but not IL-6.

The amount of wear debris was related to the presence of macrophages and giant cells (p< 0.01) but not to any of the cytokines.

There were no relationships between any of the clinical parameters and the presence of wear debris or the levels of any cytokine with the exception of IL-6 and gross loosening (p< 0.01). Similarly there were no differences between hips and knees for any of the parameters except IL-6, for which higher levels were found in hips (p< 0.05).

The results suggest that macrophages and giant cells are responsible for the majority of IL-1b, IL-8 and IL-10 production but another cell type is contributing to IL-6 production. Furthermore, IL-6 does not fit the pattern of the other cytokines as it is upregulated in hip joints compared to knees and correlates with the presence of gross loosening. This may suggest a unique role for IL-6 that requires further investigation.

This study evaluated whether obese patients who lost weight before their total joint replacement and kept it off post-operatively were at lower risk of surgical site infection (SSI) and re-admission compared with those who remained the same weight.

We reviewed 444 patients who underwent a total hip replacement and 937 with a total knee replacement who lost weight pre-operatively and sustained their weight loss after surgery. After adjustments, patients who lost weight before a total hip replacement and kept it off post-operatively had a 3.77 (95% confidence interval (CI) 1.59 to 8.95) greater likelihood of deep SSIs and those who lost weight before a total knee replacement had a 1.63 (95% CI 1.16 to 2.28) greater likelihood of re-admission compared with the reference group.

These findings raise questions about the safety of weight management before total replacement of the hip and knee joints.

Cite this article: Bone Joint J 2014;96-B:629–35.

Introduction

Ultra high molecular weight polyethylene (UHMWPE) has been used successfully as a bearing material in hip, knee, and shoulder joint replacements. However, there are problems to cause a failure in UHMWPE component, which are wear behavior and creep deformation. Continuous bearing motion and dynamic load have occurred to UHMWPE wear debris caused osteolysis in periprosthetic tissue and to plastic deformation of joint component, and subsequent aseptic loosening of components. Therefore, many studies have being carried out in order to reduce wear debris and to improve mechanical strength from UHMWPE, and there is tremendous improvement of mechanical property in UHMWPE from gamma irradiated conventional UHMWPE (GIPE), highly crosslinked PE (XLPE), and XLPE with vitamin E1, 2. Friction has a significant one of the factors effect on the wear and creep deformation. In this study, the short-term frictional behaviors of three typical types of GIPE, remelted XLPE (R-XLPE), and s annealed XLPE (A-XLPE), and XLPE with Vitamin E against Co-Cr alloy were compared under three levels of contact pressures which occured in hip, knee, and shoulder joints.

Squeaking in ceramic total hip joint replacements has become a controversial topic. This study aims to document the incidence of squeaking and other noise generation in a single surgeon series for ceramic on ceramic total hip joint replacements. Possible aetiological for squeaking causes are explored.

All patients from public and private who received ceramic on ceramic total hip joint replacements (Stryker trident-accolade) from 2002 to 2007 were identified via the New Zealand Joint registry. Following ethics approval all patients were contacted for a phone interview to question as to whether they had noted any noise generation. Patients who demonstrated noise generation were reviewed in clinic for full history and examination. Data including age, sex, weight, primary diagnosis, head size and cup size were obtained from clinical notes. Post operative x-rays were reviewed to analyse cup abduction and version.

Forty one ceramic total hip joint replacements in a total of thirty seven patients were reviewed via telephone interviews. Three patients complained of squeaking in the ceramic bearing while one patient complained of a grinding and one other of clicking. Two of the three who had recognised the squeaking were both able to reproduce the squeaking in the clinic room. The third patient was noted to have crepitus from anterior patello-femoral osteoarthritis. There was no statistical difference in age, weight, primary diagnosis or head size. In terms of abduction and version of the acetabular cups that squeaked, one had twenty seven degrees of ante-version and forty seven degrees of abduction and the other fifteen degrees of anteversion and thirty degrees of anteversion. Four cups lay outside the recommended fifteen-thirty five degrees of anteversion and thirty five-fifty five degrees of abduction yet showed no squeaking. Neither patient is troubled by the squeaking and neither would seek revision surgery. The incidence of squeaking in ceramic on ceramic total hip joint replacements appears to be around five percent with a similar number of patients experiencing other noises. The position of the acetabular cup does not appear to be the sole contributor to the noise and other aetiological causes need to be further investigated.