Bone ingrowth through porous titanium granulate around a femoral stem: histological assessment in a six-month canine hemiarthroplasty model

The procedure of using of porous titanium granules for cementless fixation of a hip replacement femoral stem was studied in a hemiarthroplasty model in 10 canines for 6 months. A vibrating instrument was used to facilitate both the delivery and distribution of the irregularly shaped porous titanium granules into the femoral canal as well as the subsequent insertion of a titanium alloy stem into the intramedullary bed of granules. Histological examination revealed lamellar bone formation through the mantle of porous titanium granules in continuity with the surrounding cortex resulting in the formation of an integrated mantle of bone and titanium granulate around the prosthesis.

Long-term results of 58 hip cup revision arthroplasties using a threaded ring implant

INTRODUCTION

There is still a discussion whether cementless hip cup revisions should be performed with a press fit cup or a threaded ring implant.

MATERIALS AND METHODS

The results of 58 hip cup changes using the spherical, threaded ring "Munich" are presented. In 16 cases, the ring "Munich I" with a smooth surface and in 42 cases the ring "Munich II" with a corundum-blasted surface were implanted. Mean follow-up was 7.5 years; radiological signs of loosening and the Harris Hip Score were examined.

RESULTS

The re-revision rate for aseptic loosening of the ring was 12/58 overall (Munich I: 5/16, Munich II: 7/42). The average Harris Hip Score was 76.2 overall (Munich I: 74.4, Munich II: 76.8). Higher survival rates were achieved with the "Munich II" ring due to improved construction details.

CONCLUSION

These rates are still below those reported for press-fit cups, the technique described by Slooff or reinforcement rings.

Activity level in young patients with primary total hip arthroplasty: a 5-year minimum follow-up

Increased activity level after total hip arthroplasty (THA) is considered a risk factor for early prosthetic failure in young patients. Forty-one primary total hip arthroplasties in 34 patients were evaluated. Walking activity was measured using a pedometer to record gait cycles. Patients completed a University of California, Los Angeles (UCLA) activity questionnaire. Linear wear rates were measured. Mean ages at surgery and final follow-up were 42 and 50.3 years, respectively (mean gait cycles per year, 1.2 million; mean UCLA score, 6; mean linear wear, 0.16 mm/y). Increased body mass index and age correlated with decreased gait cycles per year. Patients with systemic disease were less active than patients with localized hip conditions. Femoral head diameter was a predictor of linear wear. The average gait cycles per year and wear rate for this population do not appear accelerated relative to average values reported in older populations.

Three-dimensional laser micrometry characterization of surface wear in total hip arthroplasty

Even after decades of clinical use, our ability to quantify wear across total hip replacement implant surfaces is largely limited to single value measurements. The influence of patient factors on wear remains enigmatic. This pilot study for the development of three-dimensional laser micrometry (3DLM) introduces an easy, accurate means of 'mapping' and quantifying material removal. A three-dimensional laser micrometer was constructed using a laser micrometer having an accuracy of 0.5 microm. A 3D surface map is triangulated from a point cloud consisting of approximately 140,000 individual points. Comparison to a reference sphere determines radial wear over the entire surface. 3DLM was able to map and quantify fine scale surface features. Even for zirconia on relatively soft ultra-high molecular weight polyethylene, this technique maps the contributions of localized wear at the macroscopic level. The 0.5 microm (or greater) accuracy of these lasers allows us to image surfaces with a high degree of confidence. This analysis lends itself well to automation, and we anticipate that this advance will prove valuable in establishing that each head and cup combination emerging from a given clinical environment has unique wear patterns as observed in this trial data set.

Implantation of the femoral stem into a bed of titanium granules using vibration: a pilot study of a new method for prosthetic fixation in 5 patients followed for up to 15 years

This study describes a new method for the fixation of titanium hip stem prostheses based on interdigitation of irregularly shaped porous titanium granules onto bone tissue. The granules were distributed into the prepared femoral cavity using a vibrating tool, and the stem was vibrated and tapped into the bed of granules. In this pilot study, 5 patients were followed between 9 and 15 years. The clinical results were excellent and the prostheses remained stable. Autopsy (one specimen) and computer tomography (three patients) show that the granules become incorporated by bone ingrowth.

Arthroscopic-assisted core decompression of the humeral head

Humeral head osteonecrosis is a progressive disease that requires prompt diagnosis and treatment. Core decompression is a viable treatment option for early-stage cases. Most surgeons perform core decompression by arthroscopically visualizing the necrotic area of bone and using a cannulated drill to take a core. Several attempts are frequently needed to reach the proper location. In the hip multiple passes are associated with complications. We describe the use of an anterior cruciate ligament (ACL) tibial drill guide to precisely localize the area of necrotic bone. Diagnostic arthroscopy is performed to assess the areas of osteonecrosis. Core decompression is performed by use of an ACL tibial guide, brought in through the anterior or posterior portal to precisely localize the necrotic area in preparation for drilling. Under image intensification, Steinmann pins are advanced into the area of osteonecrosis. Once positioned, several 4-mm cores are made. We treated 3 patients with this technique, and all had immediate pain relief. The use of the ACL guide allows precise localization of the area of humeral head involvement and avoids multiple drillings into unaffected areas. Initial indications are that arthroscopic-assisted core decompression with an ACL guide is an effective alternative to previously used methods.

Total hip arthroplasty with a cemented, polished, collared femoral stem and a cementless acetabular component. A follow-up study at a minimum of ten years

BACKGROUND

Recent studies have suggested that cemented femoral components with a polished surface may provide superior long-term fixation when compared with femoral components with a roughened surface. The purpose of this study was to evaluate the results of total hip arthroplasty with a cemented femoral component with a polished surface finish and compare them with the results of total hip arthroplasty performed with a similar design of cemented femoral component with a rougher surface finish.

METHODS

We retrospectively reviewed a consecutive group of 132 patients (149 hips) in whom primary total hip arthroplasty had been performed by one surgeon using a cemented collared femoral component with a polished (0.1-microm Ra) surface finish and a cementless acetabular component. Ninety-eight patients (115 hips) were followed for a minimum of ten years. We compared the survivorship of this prosthesis with that of a femoral component of similar design but with rougher surfaces (matte or grit-blasted).

RESULTS

No polished stems were revised because of aseptic loosening or demonstrated radiographic evidence of loosening; however, eight hips (5.4%) with a polished stem demonstrated osteolysis distal to the greater or lesser tro-chanter. In contrast, six stems (2.0%) with a matte surface finish of 0.8-microm Ra were revised because of aseptic loosening, and an additional five stems were seen to be loose radiographically. Eleven stems (9.2%) with a grit-blasted surface finish of 2.1-microm Ra were revised because of aseptic loosening, and an additional four stems were seen to be loose radiographically. The difference in the prevalence of revision due to aseptic loosening between the group with the 0.1-microm Ra surface and the group with the 2.1-microm Ra surface was significant (p = 0.001), as was the difference between the prevalence of revision due to aseptic loosening between the group with the 0.8-microm Ra surface and the group with the 2.1-microm Ra surface (p = 0.001). No cups were revised because of aseptic loosening, and one hip had radiographic signs of acetabular loosening.

CONCLUSIONS

This study demonstrated excellent durability of a prosthesis consisting of a cemented, collared, polished femoral component and a cementless acetabular component. While no hips were revised because of aseptic loosening, distal femoral osteolysis was observed in eight hips (5.4%), a higher prevalence than has been reported by others after similar durations of follow-up of tapered, collarless, polished femoral components.

Spontaneous thrombus formation in a normal left ventricle following administration of large doses of epoietin

We present a case of a thrombus formation within the left ventricle of a patient with a normal heart, who had previously been receiving high doses of erythropoietin for an inappropriately prolonged period.

Nonsteroidal anti-inflammatory drugs: are they safe after joint arthroplasty for early pain?

A significant proportion of patients will experience moderate to severe pain after hip or knee replacement surgery. Multimodal pain control regimens have been developed to address this issue. These regimens may include the use of nonsteroidal anti-inflammatory drugs (NSAIDs). Concern over excessive bleeding in the perioperative period, especially in joint arthroplasty patients receiving anticoagulation therapy, generally prohibits the use of nonspecific NSAIDs. Cyclooxygenase-2 inhibitors, a class of NSAIDs, are not believed to increase the risk of bleeding and may be useful in this population of patients. However, recent research shows increased cardiovascular and renal risks with cyclooxygenase-2 inhibitors and has limited their use for postoperative pain control in joint arthroplasty patients.

Total hip arthroplasty wear simulation using the boundary element method

In this paper an application of the boundary element method for simulating wear in total hip prosthesis is presented. Several examples including different update periods of the worn acetabular cup, various femoral head sizes and various materials for both the femoral head and the acetabular cup are simulated under the same variable loading conditions for up to 20 years of service. Moreover, two different femoral models are considered in order to investigate the influence of the femoral modelling. The analysis demonstrates that due to the boundary only modelling requirement, the computational time and storage remains low, allowing large service periods to be simulated. Generally, the results obtained are in good agreement with other researchers findings. Moreover, ignoring the bending of the femoral neck in the model, results in a small overestimation of the maximum wear depth, while the volumetric wear is slightly underestimated. However, these differences are trivial considering the reduction of the computational effort.

Results of adjusted-dose heparin for thromboembolism prophylaxis in knee replacement compared to those found for its use in hip fracture surgery and elective hip replacement

The purpose of this study was to compare the results of adjusted-dose heparin (ADH) in the prevention of thromboembolism in knee replacement with those obtained for its use hip fracture surgery and elective hip replacement. Ultrasound was used to diagnose deep vein thrombosis (DVT) and ventilation/perfusion (V/Q) scan to diagnose pulmonary embolus (PE). Analysis of 438 operations was available. DVT was present after 9.7% of knee replacements, 7.2% of hip fracture operations and 6.8% of elective hip replacements. PE occurred in 1.2% of knee replacements, 0.9% of hip fracture operations and 2.5% of elective hip replacements. Proximal DVT occurred in 4.2% of knee replacements, 3.6% of hip fracture operations and 4.3% of elective hip replacements. Complications of heparin occurred in 4.6% of patients. Our ADH protocol was equally effective in prophylaxis against thromboembolism in knee replacement, hip fracture surgery and elective hip replacement. Direct comparison with other methods should not be done because ultrasound was used to screen for DVT.

Total hip arthroplasty in secondary systemic lupus erythematosus femoral head avascular necrosis

Systemic lupus erythematosus is a multisystem disease with a large spectrum of clinical manifestations and a variable course. Lupus is marked by both humoral and cellular immunologic abnormalities, including multiple auto-antibodies especially anti DNA antibodies. Epidemiology - female predominance, occurring usually between second and fourth decade of life, more frequently in hispanic and black patients. Family predominance has been noticed. Provocative agents - ultraviolet light, viral infections, drugs and situational stresses. Pathogenesis - pathological features can affect a large spectrum of internal organs and systems - osteoarticulary injuries, skin rash, lymphadenopathy, glomerulonephritis, myocarditis, digestive system lesions. Musculo skeletal abnormalities include migratory arthritis, effusion and stiffness in small and large joints. Articular erosions are uncommon. Skeletal abnormalities include osteopenia and osteonecrosis, due to two pathological mechanisms: vasculitis and long term corticotherapy. Fifteen to twenty percent of SLE patients are affected by femoral head avascular necrosis (FHAN). Diagnosis rests on clinical signs - hip pain, limited range of motion, walking with a limp.; radiological findings - best grouped in Arlet-Ficat standing system; MRI - high sensitivity, especially in infraradiological stages. Treatment - in incipient stages core decompression represents the best therapeutical option. In advanced, arthritis stages, total hip arthroplasty (THA) is the standart treatment. Three implant types are available: bipolar, uncemented and cemented. An increased number of cotyloidites occurred after bipolar implants. Emphasised osteopenia and excessive bleeding represent contraindications for uncemented implants. Considering all of this, cemented implants are considered, the right choice, methacrylate cement providing strong and durable fixation of THA implants to bone. No meaningful differences were observed in postoperative functional recovery between LSE patients and other etiology FHAN patients.

Toll-like receptors in the interface membrane around loosening total hip replacement implants

Toll-like receptors (TLRs) have been known to act as sensors of innate immunity and respond to ligands of microbial and endogenous components. Tissues and cells typical for interface membrane of foreign body reaction were analyzed to evaluate potential role of TLRs in the pathogenesis of the so called "aseptic loosening of total hip replacement." Fourteen cases of interface membrane around aseptic loose total hip replacement implants were stained by single and double immunohistochemical methods to examine cellular localization of toll-like receptor (TLR)-4 and TLR-9. Osteoarthritic synovium was used as control tissues. Cultured macrophages were used to study TLR-4 and TLR-9 mRNA levels by quantitative reverse transcriptase-polymerase chain reaction. The effect of titanium particle stimulation on macrophages was also examined in the culture. Extensive immunolocalization of TLR-4 and TLR-9 positive cells was observed in the synovial membrane-like interface membrane of foreign body granulomas compared with control synovial membranes. TLR and CD68 double staining demonstrated that the TLR positive cells in aseptic loosening were mostly monocyte/macrophages and foreign body giant cells. TLR-4 and TLR-9 mRNA expression was also found in macrophage-colony stimulating factor treated rat macrophages, but this expression decreased (p < 0.05 or less) upon stimulation with titanium particles although matrix metalloproteinase (MMP)-9 mRNA levels used as macrophage activation marker were increased (p = 0.01). The interface membrane around loosening total hip replacement implants is apparently well equipped with TLRs and, thus, probably very sensitive to various structural components of microbes and to endogenous TLR ligands. This seems to be due to recruitment of monocyte/macrophages as particles per se seemed to down-regulate some of the key TLRs. This suppression after particle phagocytosis might prevent excessive and harmful host responses, and injury to innocent bystander cells/tissues.

System for intraoperative evaluation of soft-tissue-generated forces during total hip arthroplasty by measurement of the pressure distribution in artificial joints

A system for evaluating the soft-tissue-generated forces at the hip joint was developed. The system enabled measurement of contact pressure distribution at hip joint surfaces, as well as evaluation of the artificial hip joint condition during total hip arthroplasty (THA). First, a pressure sensor module that forms part of the artificial joint was constructed. Eight small pressure sensors were installed in the spherical head component of the ball-and-socket joint. Next, software for recording and visualizing the detected pressures at 1-millisecond intervals was developed. The pressure distribution was displayed in real time via 3D computer graphics on a monitor. The system enabled intuitive recognition of the direction of soft-tissue-generated forces and pressure distribution in three dimensions. Accuracy tests were conducted using a high-accuracy 6-degree-of-freedom positioning device and digital force gauge. The error between the applied loads and measured forces was 3.42 +/- 3.26 N (mean +/- standard deviation) for each coordinate in 10 trials involving load application from 10 different directions. Next, a clinical evaluation was conducted during THA. The relative positions of the cup and stem component were measured using a surgical navigation system simultaneously with the pressure measurement. The system allowed real-time acquisition of information regarding the artificial hip joint, as well as comparison of the differences in the hip condition when several types of neck were used. Further improvements to the calibration method should enable more accurate measurements. We believe this system will be a useful tool for selecting an appropriate implant that fits a patient's hip joint or for estimating the risk of complications following surgery.

Evaluation of an expandable stem total hip replacement system

The expandable nail concept uses high-pressure saline to inflate the diameter of a cylindrical implant to achieve fixation within the medullary canal of bone. Expandable nails are used clinically in a number of fracture management applications and have been more recently developed as a femoral component for total hip replacement. In this study, the expandable total hip replacement stem design was evaluated, specifically testing to determine if acrylic cement can be used in place of saline for permanent expansion, to observe the amount of stem subsidence after cyclic loading, and to document if stem expansion creates untoward stresses in the femur. The results included that the expandable femoral component could be expanded with cement if careful control of cement viscosity is used with a modified filling technique. Neither untoward hoop strains nor stem subsidence was found in tests with the cadaveric femurs. Bench testing has confirmed the stability of these stems. In addition, the substitution of cement for saline would make the construct permanent, avoiding the risk of deflation and loosening. The concept of an expandable femoral prosthesis is appealing and would have many potential clinical applications. The need for cemented stems or the more difficult and costly "Ling technique" could be avoided with their use in tumor surgery, hip fracture management, and total hip replacements associated with osteoporosis or a patulous femora in both primary and revision settings.

[When should secondary procedures be performed in residual hip dysplasia?]

Residual hip dysplasia is one of the most important complications following treatment of developmental hip dysplasia. If untreated, this condition will cause problems during maturity. The acetabulum consists of the ilium, ischium, pubis, and the triradiate cartilage lying between them. Interstitial growth from the growth plates of the triradiate cartilage plays an important role in the development of the acetabulum. Concentricity and congruity should be maintained during this development, which is very fast during the first eight years and continues until maturity. Whether residual hip dysplasia will occur can be anticipated by evaluating the factors that are effective on this development during the treatment of developmental hip dysplasia. The main prognostic factors include the age of the patient, concentricity and congruity of the hip, sphericity of the femoral head, the distance from the center to the head, and the thickness of the acetabular roof. Taking these factors into consideration during the follow-up is important to eliminate overtreatment and to assess the success of treatment.

Surface micro-analyses of long-term worn retrieved “Osteal™” alumina ceramic total hip replacement

We analyzed wear pattern of long-term retrieved alumina-alumina hip prostheses from Osteal, which were implanted for 15-19 years. A comparison was carried out with our previous study of 17-year Biolox alumina-on-alumina hip prostheses, (Shishido et al., J Biomed Mater Res B 2003;67:638-647) and all-alumina total hip replacement run under microseparation simulator tests. Of particular interest was the occurrence of stripe wear in these first generation alumina ceramic bearings. Two balls of Osteal revealed only one stripe wear as did the respective liners on their rim areas. In these latter balls, the stripes were shallower than those previously observed in Biolox implants. A microscopic analysis of the bearing surface was carried out using scanning electron microscopy and fluorescence microprobe spectroscopy. On average, the Osteal retrievals had one grade lower wear than Biolox retrievals. Fluorescence microprobe maps showed that Biolox ball surfaces had higher compressive stress than the Osteal likely due to severe impingement and microseparation promoted by the bulky implant design.

Biofilm formation by bacteria isolated from retrieved failed prosthetic hip implants in an in vitro model of hip arthroplasty antibiotic prophylaxis

Bacterial infection primarily with Staphylococcus spp. and Propionibacterium acnes remains a significant complication following total hip replacement. In this in vitro study, we investigated the efficacy of gentamicin loading of bone cement and pre- and postoperative administration of cefuroxime in the prevention of biofilm formation by clinical isolates. High and low initial inocula, representative of the number of bacteria that may be present at the operative site as a result of overt infection and skin contamination, respectively, were used. When a high initial inoculum was used, gentamicin loading of the cement did not prevent biofilm formation by the 10 Staphylococcus spp. and the 10 P. acnes isolates tested. Similarly, the use of cefuroxime in the fluid phase with gentamicin-loaded cement did not prevent biofilm formation by four Staphylococcus spp. and four P. acnes isolates tested. However, when a low bacterial inoculum was used, a combination of both gentamicin-loaded cement and cefuroxime prevented biofilm formation by these eight isolates. Our results indicate that this antibiotic combination may protect against infection after intra-operative challenge with bacteria present in low numbers as a result of contamination from the skin but would not protect against bacteria present in high numbers as a result of overt infection of an existing implant.

Assessment of acetabular version by plain radiograph

Radiographs are routinely used to assess the condition and position of the acetabular component. The condition of the cement mantle, or the ingrowth potential, is usually easily recognized. Component-bone position can be assessed by using the method of Ranawat or by measuring abduction angles. Assessment of the version of an acetabular component is often overlooked. This angle or position is important relative to instability, impingement, and motion abnormality. The opening angle or version can be implied from a true acetabular or cross-table lateral radiograph, but good-quality views are often difficult to obtain on an outpatient basis. Using the simple technique presented here, clinicians can assess the acetabular component for version on the basis of plain anteroposterior pelvis and hip radiographs.

Design and implementation of gradient vector flow snake to detect a reference object in pelvic x-rays for preoperative total hip arthroplasty planning application

The main interest of this research project is to promote automation in performing preoperative planning for hip joint replacement surgery using a special medical image viewing software, ViewPro. Preoperative planning is performed to carefully prepare the surgery and to accurately select the hip implants. The first step of preoperative planning is to calibrate the x-ray image to adjust the magnification factor. A femoral head implant is used as magnification factor reference. Automation is introduced by developing an algorithm to automatically detect this reference object in the image. The algorithm used for performing the automatic detection of the reference object is gradient vector flow (GVF) snake. A study has been performed to compare the newly developed semiautomatic algorithm to the old manual calibration algorithm. The results show a close relation between the two algorithms (less than 1% of average relative difference). It is concluded that the developed semiautomated algorithm can be used as an alternative for performing the manual calibration.

Who, when, and why total joint replacement surgery? The patient's perspective

PURPOSE OF REVIEW

Although total joint replacement is an effective treatment for advanced arthritis, many whom might benefit are unwilling to consider this procedure. This review highlights advances in understanding of patients' perceptions of total joint replacement.

RECENT FINDINGS

Research shows that patients' willingness to consider total joint replacement varies by sex, race/ethnicity, and socioeconomic status as a result of systematic differences in knowledge and beliefs about the procedure. Individuals with low socioeconomic status and minorities view the procedure less favorably than their wealthier, white counterparts, possibly partly explaining disparity in rates of use of the procedure among these groups. Among those undergoing total joint replacement, up to 30% experience a suboptimal outcome or are dissatisfied with results. Early work suggests that patients' expectations and self-efficacy are important potential predictors of postoperative outcome. Patient information needs regarding total joint replacement vary significantly and possibly systematically by sex and race/ethnicity. Available information materials may not address the concerns of many individuals contemplating the procedure, posing a potential barrier to surgery.

SUMMARY

Targeted culturally sensitive knowledge dissemination strategies are needed to improve the knowledge and beliefs of people with hip/knee arthritis about total joint replacement.

Acute destruction of the hip joints and rapid resorption of femoral head in patients with rheumatoid arthritis

We report three rheumatoid arthritis (RA) cases with acute destruction of hip joint and rapid resorption of femoral head. The condition occurred in less than 6 months and closely resembled rapid destructive coxarthrosis. All three patients were postmenopausal women with active RA who had been taking steroids. Two of the patients were taking prednisolone (PSL) of over 20 mg as maximum dose per day, and all patients were resistant to disease-modifying anti-rheumatic drugs (DMARDs). Other than the problems of their hip joints, one had a giant bursitis around the pathological side of the hip joint, another had multiple rheumatoid nodules and skin infarction, and the other suffered from insufficiency fracture of the contralateral femoral subcapital lesion. As a result, all of them had total hip arthroplasty. We recommend taking repetitive radiographs for RA patients with continuing severe hip pain.

The Alberta Bone and Joint Health Institute: creating sustainable accountability through collaboration, relevant measurement and timely feedback

A robust accountability strategy is at the core of creating a safe, efficient, effective and sustainable system of healthcare. The commitment to be accountable must extend far beyond the providers of care to include every person involved in the funding, administration, delivery and support of patient care (both directly and indirectly). The Alberta Bone and Joint Health Institute has fostered a new system that will measure, analyze and give valuable feedback to all stakeholders in all three essential domains of system accountability: access, quality and cost. The Institute has employed four key strategies to create system accountability in a hip and knee pilot project: collaboration between stakeholders in defining goals and measures that matter to them; the use of "world's best evidence" to drive decisions and to establish goals and benchmarks to measure against; collection of useful data and its analysis to inform improvement decisions; and timely feedback of relevant data in domains of interest to stakeholders on system outputs in the key domains. While these strategies have not yet been proven to be effective in creating the desired "culture of accountability," they are having a significant clinical impact and do have potential to lead to that outcome.