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BACKGROUND: A porous Ti6Al4V implant that is manufactured using selective laser melting (SLM) has broad potential applications in the field of orthopaedic implants. The pore structure of the SLM porous Ti6Al4V implant allows for cell migration and osteogenic differentiation, which is favorable for bone ingrowth and osseointegration. However, it is unclear whether the pore structure and partially melted Ti6Al4V particles on a SLM porous Ti6Al4V implant will increase bacterial adhesion and, perhaps, the risk of implant-related infection. QUESTIONS/PURPOSES: (1) Is there more bacterial adhesion and colonization on SLM porous Ti6Al4V implants than on polished orthopaedic implants? (2) Do partially melted Ti6Al4V particles on SLM porous Ti6Al4V implants reduce human bone mesenchymal stem cells (hBMSCs) adhesion, viability, and activity? METHODS: To determine bacterial adhesion and biofilm formation, we incubated five different Ti6Al4V discs (polished, grit-blasted, plasma-sprayed, particle SLM porous, and nonparticle SLM porous discs) with methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli. Bacterial coverage on the surface of the five different Ti6Al4V discs were evaluated based on scanning electron microscopy (SEM) images quantitatively. In addition, a spread-plate method was used to quantitatively evaluate the bacterial adhesion on those implants. The biofilm formation was stained with crystal violet and semi-quantitatively determined with a microplate reader. The morphology and adhesion of hBMSCs on the five Ti6Al4V discs were observed with SEM. The cell viability was quantitatively evaluated with a Cell Counting Kit-8 assay. In addition, the osteogenic activity was determined in vitro with a quantitatively alkaline phosphatase activity assay and alizarin-red staining. For semiquantitative analysis, the alizarin-red stained mineralized nodules were dissolved and determined with a microplate reader. RESULTS: The polished discs had the lowest MRSA adhesion (8.3% ± 2.6%) compared with grit-blasted (19.1% ± 3.9%; p = 0.006), plasma-sprayed (38.5% ± 5.3%; p < 0.001), particle (23.1% ± 2.8%; p < 0.001), and nonparticle discs (15.7% ± 2.5%; p = 0.003). Additionally, when comparing the two SLM discs, we found that particle discs had higher bacterial coverage than nonparticle discs (23.1% ± 2.8% versus 15.7% ± 2.5%; p = 0.020). An E. coli analysis showed similar results, with the higher adhesion to particle SLM discs than to nonparticle discs (20.7% ± 4.2% versus 14.4% ± 3.6%; p = 0.011). In addition, on particle SLM porous discs, bacterial colonies were localized around the partially melted Ti6Al4V particles, based on SEM images. After a 7-day incubation period, the cell viability in the particle group (optical density value 0.72 ± 0.05) was lower than that in the nonparticle groups (optical density value: 0.87 ± 0.08; p = 0.003). Alkaline phosphatase activity, as a marker of osteogenic differentiation, was lower in the particle group than in the nonparticle group (1.32 ± 0.12 U/mL versus 1.58 ± 0.09 U/mL; p = 0.012). CONCLUSION: Higher bacterial adhesion was observed on SLM porous discs than on polished discs. The partially melted Ti6Al4V particles on SLM porous discs not only enhanced bacterial adhesion but also inhibited the osteogenic activity of hBMSCs. Postprocessing treatment is necessary to remove partially melted Ti6Al4V particles on an SLM implant before further use. Additional studies are needed to determine whether an SLM porous Ti6Al4V implant increases the risk of implant-related infection in vivo. CLINICAL RELEVANCE: As implants with porous Ti6Al4V made using SLM are being designed, our preliminary findings suggest that postprocessing treatment is needed to remove partially melted Ti6Al4V particles before further use. In addition, the depth of the porous structure of the SLM implant should not exceed the maximum depth of bone ingrowth because the host immune defense cannot prevent bacterial adhesion without integration.

This study aims to assess and compare the value of FDG PET with combined In-labeled leukocyte/Tc-sulfur colloid bone marrow (WBC/BM) imaging for diagnosing infection in hip and knee prostheses.In this prospective study, patients with painful hip or knee arthroplasty, who were scheduled to undergo clinical and diagnostic evaluation for prosthesis revision, were included. They have been studied by using FDG PET and WBC/BM scan. This study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. All patients provided written informed consent.A total of 134 hip and 87 knee prostheses, suspected of being either infected or noninfectious loosening, were evaluated. All 221 prostheses underwent FDG PET, whereas both WBC/BM imaging and FDG PET were performed in 88 prostheses. The initial analysis of data from the WBC/BM images demonstrated somewhat suboptimal results compared with those of FDG PET scans on 88 patients. In addition, some patients were not willing to undergo both procedures and therefore participate in this study. Therefore, a decision was made to eliminate WBC/BM imaging from the procedures for the remainder of this research study. This decision was reached partly because of the significant radiation dose delivered from labeled WBC and safety issues related to preparing these labeled cells. Final diagnosis was based on microbiological examinations of the surgical specimens in 125 prostheses and joint aspirations combined with the clinical follow-up of 6 months or more in 86 prostheses. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET in hip prostheses were 81.8%, 93.1%, 79.4%, and 94.0%, respectively, and in knee prostheses were 94.7%, 88.2%, 69.2%, and 98.4%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of WBC/BM imaging in hip prostheses were 38.5%, 95.7%, 71.4%, and 84.6%, respectively, and in knee prostheses were 33.3%, 88.5%, 25.0%, and 92.0%, respectively. In those cases that underwent both FDG PET and WBC/BM imaging, there was a trend (P = 0.0625) toward a higher sensitivity for FDG PET in hip prostheses, whereas other comparisons did not show any significant differences between the 2 imaging modalities.Based on this study, the diagnostic performance of FDG PET scan in detecting infection in painful hip and knee prostheses is optimal for routine clinical application. Considering the complexity and costs of WBC/BM imaging and related safety issues associated with this preparation, FDG PET seems to be an appropriate alternative for assessing these patients.

The purpose of this study was to evaluate the outcome of femoral component revisions using a long tapered HA coated femoral revision stem. Between 2001 and 2008, 55 femoral component revisions were performed using this stem. Forty-one patients were available for follow up evaluation at average of 59 months. The clinical results were evaluated using the HHS and serial radiographs were evaluated for loosening. The mean HHS was 71 (range 22–100). Three hips required revision of KAR stem (1 aseptic loosening, 1 infection, 1 limb length discrepancy). Only one prosthesis demonstrated radiographic evidence of subsidence. Our study suggests that long tapered HA coated revision femoral components can provide stable fixation and in-growth in cases where there is good proximal femoral bone stock and favorable canal geometry.

†Background: Aseptic loosening of cemented hip prostheses is recognized as a long-term problem, and especially in males and younger patients. Much energy has been focused on developing new prostheses that are designed for cementless fixation. We evaluated the performance of and periprosthetic bone response to a tapered, titanium, hydroxyapatite (HA)-coated femoral hip prosthesis at a minimum of 7 years of follow-up after treatment with primary total hip arthroplasty. Methods: Seventy-eight patients and 86 hips were included in the study. There were 35 men and 43 women; the mean age at the time of the operation was 59 years (range, 41 to 81 years). We used a tapered, titanium (Ti6Al4V), HA-coated femoral implant. We evaluated the patients at a minimum of 7 years of follow-up after treatment with primary total hip arthroplasty. Clinical evaluation was performed using the scoring system and the hip scores were assigned according to the level of pain, the functional status and the range of motion. The patients who refused to return, but who did forward X-rays for review after being contacted were questioned by phone about the functional status of their hip. Radiographic follow-up was performed at six weeks, at three, six and twelve months and yearly thereafter. All the available radiographs were collected and assessed for implant stability, subsidence, osseointegration, osteolysis, stress shielding and evidence of periprosthetic lucency. Results: Eighty-six hips (78 patients) were available for review at follow-up of greater than 7 years. In 11 of the 86 cases, acetabular failure required revision of the acetabular component, but the femoral stem survived and it was available for long-term evaluation. The radiographs were obtained at 7-year follow-up for another 20 hips, but the patients would not come in for the 7-year clinical evaluation. Therefore, a phone interview was conducted to assess any change in the functional status at a minimum of 7 years. Conclusions: The mechanical fixation of a tapered, titanium, HA-coated femoral implant was excellent in this study. This femoral design provided reliable osseointegration that was durable at a mean of 7 years follow-up.

A poll was initially attempted to elucidate what type of skin incision would be preferred by the patients. The retrospective analysis of index cases was preformed to reveal the gains and losses of small incision transgluteal THA. We performed a poll on the preferred type of skin incision to the patients, their families and the medical personnel in orthopedic department in a face-to-face manner. According to the result of the poll, we changed approaches from a standard transgluteal to a small incision transgluteal approach. Each 20 consecutive index patients that underwent standard or small-incision transgluteal THA were followed and compared for more than 2 years. The small incision THA group showed more rapid mobilization, shorter hospital stay, and better early satisfaction. However, no clinical benefits of small incision were observed after 6-weeks postoperatively. There were significant variations in implant alignments. More early major complications such as dislocation, intraoperative femoral fracture or leg length inequalities occurred in the small incision group. The use of a small incision in THA resulted in subtle and temporary gains, at the cost of several major early complications. Now we perform THA with definitely smaller incision than before but we do believe that performing a stable and well-aligned THA is far more important than the length or amount of surgical dissection.

Purpose.To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses.Methods.Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-on-ceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability).Results.The mean follow-up period was 54 (range, 24–110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1–10) to 7.7 (range, 2–10) [pConclusion.Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes.

Background: Several studies have documented that the size of the osteonecrotic lesion in the femoral head is an essential parameter in determining prognosis and treatment. There are several methods currently available to measure lesion size, but no general agreement as to which is most useful. In the present study, three different radiographic methods for determining lesion size were evaluated and compared. Methods: Anteroposterior and lateral radiographs of forty-two hips with osteonecrosis were examined. The extent of osteonecrotic involvement of the femoral head was determined through the use of three different methods: the volume of necrosis by quantitative digital image analysis, and the angular measurements described by Kerboul et al. and Koo and Kim. Graphs were constructed to demonstrate these relationships. Results: Volumetric measurement appeared to be the most reliable. There was only a rough correlation with angular measurements. Several sources of error were noted when simple angular measurements of irregular, three-dimensional lesions were used. The Kerboul method routinely overestimated lesion size and designated 81% of the lesions as “large.” The modified Koo and Kim method provided a more even distribution of lesion size and correlated with volumetric measurements in 74% of hips (thirty-one of forty-two hips). Conclusions: Quantitative volumetric measurements appear to be the most reliable method to measure the true size of a three-dimensional osteonecrotic lesion of the femoral head. Volumetric measurement is more accurate than angular measurement and can be performed easily with modern technology. Angular measurements, although somewhat simpler to use than volumetric measurements, may provide only a rough estimate of lesion size, partly due to the considerable differences in outline or location of the necrotic segments. Nevertheless, determination of lesion size must be part of a comprehensive system of staging of this disease, which includes the evaluation of other parameters, such as the extent and degree of articular surface involvement and the status of the hip joint and the acetabulum. Level of Evidence: Diagnostic Level III. See Instructions to Authors on [jbjs.org][1] for a complete description of levels of evidence. [1]: http://jbjs.org

We aimed to compare the accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) with technetium-99m sulfur colloid 111indium-labeled white blood cell scintigraphy (TcSC-Ind BM/WBC) in diagnosis of periprosthetic infection. Eighty-nine patients with 92 painful hip prostheses were recruited prospectively and given the option of undergoing either combined FDG-PET and TcSC-Ind BM/WBC or FDG-PET only. FDG-PET correctly diagnosed 20 of the 21 infected cases (sensitivity, 95.2%) and ruled out infection in 66 of the 71 aseptic hips (specificity, 93%) corresponding to a positive predictive value of 80% (20/25) and a negative predictive value of 98.5% (66/67). TcSC-Ind BM/WBC correctly identified 5 of the 10 infected cases (sensitivity, 50%) and 39 of 41 aseptic cases (specificity, 95.1%) corresponding to a positive and negative predictive values of 41.7% (5/12 cases) and 88.6% (39/44 cases), respectively. Based on these preliminary results, FDG-PET appears to be a promising diagnostic tool for distinguishing septic from aseptic painful hip prostheses.

Bioactive glass granules were implanted in the paraspinal muscle of rabbits to determine the pathway of the silicon released from bioactive glass in vivo. We traced and quantified the silicon released by obtaining 24-h urine and blood samples for up to 6 months after implantation. Furthermore, local muscle tissue as well as the following organs were resected for chemical and histopathological analyses: brain, heart, kidney, liver, lung, lymph nodes, spleen, and thymus. The urinary silicon of the group with implanted granules was significantly higher than in the sham-operated, control group. The average excretion rate was 2.4 mg/day, and as such, 100% of the implanted silicon was excreted in 19 weeks. No elevated concentrations of silicon were found at the implant sites or in the other organs at sacrifice, that is, 24 weeks. The histological appearance of all organs was normal throughout. The concentrations of silicon measured in the urine were well below saturation and because no significant increase in silicon was found in any organ, including kidney, the increased silicon excretion rate was within the physiological capacity of rabbits. Therefore, it can be concluded that the resorbed silica gel is harmlessly excreted in soluble form through the urine.

Hip arthroplasty is a common surgical procedure, but the diagnosis of infection associated with hip arthroplasty remains challenging. Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been shown to be a promising imaging modality in settings where infection is suspected. However, inflammatory reaction to surgery can result in increased FDG uptake at various anatomic locations, which may erroneously be interpreted as sites of infection. The purpose of this study was to assess the patterns and time course of FDG accumulation following total hip replacement over an extended period of time. Firstly, in a prospective study nine patients with total hip replacement were investigated to determine the patterns of FDG uptake over time. Three FDG-PET scans were performed in each patient at about 3, 6 and 12 months post arthroplasty. Secondly, in a retrospective analysis, the medical and surgical history and FDG-PET imaging results of 710 patients who had undergone whole-body scans for the evaluation of possible malignant disorders were reviewed. The history of arthroplasty and FDG-PET findings in the hip region were reviewed for this study. Patients with symptomatic arthroplasties or related complaints during FDG-PET scanning were excluded from the analysis. During the entire study period, all nine patients enrolled in the prospective study were demonstrated to have increased FDG uptake around the femoral head or neck portion of the prosthesis that extended to the soft tissues surrounding the femur. Among the patients reviewed in the retrospective study, 18 patients with a history of 21 hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the criteria for inclusion. The time interval between the hip arthroplasty and the FDG-PET study ranged from 3 months to 288 months (mean+/-SD: 80.4+/-86.2 months). In 81% (17 of 21) of these prostheses, increased FDG uptake could be noted around the femoral head or neck portion of the prosthesis. The average time interval between arthroplasty and FDG-PET scan in these patients was 71.3 months. In only four prostheses (19%, 4 of 21) was no abnormally increased FDG uptake seen around the prostheses or adjacent sites. The average time interval in these patients was 114.8 months. It is concluded that following hip arthroplasty, non-specifically increased FDG uptake around the head or neck of the prosthesis persists for many years, even in patients without any complications. Therefore, to minimize the number of false-positive results for infection with PET studies obtained to evaluate a painful hip prosthesis, caution should be exercised when interpreting FDG uptake around the head or neck portion of the prosthesis.

Impaction grafting has been used successfully in revision total knee arthroplasty. Histology and preliminary clinical results show that this technique may be useful in situations in which bone loss is extensive. In contrast to bulk allografts, morcellized graft remodels and incorporates with the host. The preliminary results and technique are reviewed briefly.

Background: In an effort to decrease the rate of aseptic loosening, certain cemented femoral components were designed to have a roughened or textured surface with a methylmethacrylate precoating. Reports differ as to whether this step has increased or decreased the rate of failure. This study was designed to evaluate this issue. Methods: Five hundred and fourteen hips treated with a cemented Harris Precoat stem (Zimmer, Warsaw, Indiana) were evaluated clinically and radiographically and compared with 254 hips treated with an uncoated Harris Design-2 stem (Howmedica, East Rutherford, New Jersey). Prostheses that had been removed at revision were examined. The cementing and surgical techniques were identical and the population demographics were similar for these two groups. Results: The mean durations of follow-up were 8.4 and 13.5 years for the Precoat and uncoated Design-2 stems, respectively. At those times, at least forty-nine (9.5%) of the 514 Precoat components and at least ten (3.9%) of the 254 uncoated Design-2 stems had failed (p = 0.006). Five Precoat stems fractured, and no uncoated Design-2 stems fractured. Component failure was associated with use in young, active, heavy men with a diagnosis of avascular necrosis and generally with the use of smaller components. The cementing technique was satisfactory in the majority of the patients, and there were no qualitative differences in cementing technique between the hips that failed and those that did not. The mechanisms of failure of the Precoat prostheses included bone-cement loosening, focal osteolysis, stem fracture, and prosthesis-cement debonding. Fractures of smaller components occurred as a result of fatigue failure and were associated with good distal fixation but proximal stem loosening. Conclusions: The rate of failure of roughened, precoated, cemented femoral components was considerably higher and occurred earlier than that of femoral components that were neither textured nor precoated with methylmethacrylate. Younger patients with avascular necrosis had a higher risk of failure; however, this factor alone did not completely explain the differences in outcome between these two components. The causes of aseptic loosening are multifactorial and may be related to component design and size as well as to precoating and surface finish.

The use of an elevated-rim acetabular liner in total hip arthroplasty is widely accepted. We sought to determine quantitatively the amount of additional stability provided by the elevated-rim liner compared with the standard nonelevated liner. The stability of the hip with a 32-mm femoral head was compared with the standard 28-mm head. Our results show that a 15 degrees elevated-rim acetabular liner placed in the posterior quadrant increased hip stability by an additional 8.9 degrees of internal rotation. Similarly the 32-mm head provided 8.1 degrees of additional internal rotation. The increases were statistically significant (P

The development of periprosthetic fractures around loose femoral components can be a devastating event for patients who have undergone total hip arthroplasty (THA). As indications for THA expand in an aging population and to use in younger patients, these fractures are increasing in incidence. This review covers the epidemiology, risk factors, prevention, and clinical management of periprosthetic femoral fractures. Treatment principles and reconstructive options are discussed, along with outcomes and complications. Femoral revision with a long-stem prosthesis or a modular tapered stem is the mainstay of treatment and has demonstrated good outcomes in the literature. Other reconstruction options are available, depending on bone quality. Surgeons must have a sound understanding of the diagnosis and treatment of periprosthetic femoral fractures.

This article discusses current bearing-surface alternatives for long-term total hip articulations involving metal-polyethylene, ceramic-polyethylene, metal-metal, and ceramic-ceramic couples. The enduring success of the low-friction arthroplasty advanced by Sir John Charnley as a solution for painful hip problems can be appreciated by the fact that, in 1999, more than 270,000 hip arthroplasties were performed in the United States. Over the last three decades, patient profiles have changed substantially, resulting in demands for a greater service life of ultra-high molecular weight polyethylene hip components. Material failure, often leading to an osteolytic response, is increasingly associated with younger, more active patients. In this context, the low-friction solution has become a problem, limiting in vivo system longevity (Figs. 1 and 2). Fig. 1: A marked osteolytic response in a fifty-year-old patient. Fig. 2: Corresponding intracellular polyethylene debris viewed under polarized light. Previous attempts to improve the performance of ultra-high molecular weight polyethylene have included carbon-fiber reinforcement (Poly-2) and, more recently, polymer reprocessing to enhance mechanical properties (Hylamer). The former was withdrawn from the market because of excessive inflammatory response, whereas the latter has been linked to debris-induced osteolytic responses in early reports. Laboratory simulation has demonstrated that the resistance of ultra-high molecular weight polyethylene to wear is improved with increased cross-linking of the carbon-hydrogen polymer chains. A number of thermal and chemical processing solutions have been described. One such approach involves component storage at elevated temperatures in an oxygen-depleted environment. This is done following irradiation and encourages kinetic recombination of the carbon-hydrogen free radicals created by the radiation process. Other techniques deliver increased radiation doses to the component material followed by remelting to quench free radicals. While this results in dramatic wear reduction in laboratory simulations (Fig. 3), it also changes the amorphous and crystalline regions of the polymer, affecting mechanical properties and potentially reducing fatigue strength. …

In 1997, two manufacturers began Food and Drug Administration approved investigations of a ceramic-on-ceramic (alumina) articulation total hip replacement in the United States. Osteonics (Allendale, NJ) and Wright Medical Technology (Arlington, TN) enrolled more than 500 and 300 patients, respectively, when their studies ended in the middle part of 1998. The author presents detailed early results of the series by Wright Medical Technology. Three hundred thirty-three patients were enrolled in 11 centers around the country in a prospective series. All patients received the Transcend ceramic-on-ceramic articulation and have a minimum of 18 months followup with a range of 18 to 36 months. Harris hip scores increased on average from 44 to 97 points. Four patients underwent revision surgery; one for deep infection, one for early migration of the cup, one for dislocation, and one for liner malplacement. Overall, there were 42 complications. Seven were systemic and 35 were related to the total hip replacement. Four of the 35 complications were ceramic related and included three chipped liners and one eccentric seating of the cup liner. To date, no patient underwent revision surgery for aseptic loosening. Seven technical guidelines are suggested to enhance the quality of the intraoperative and postoperative results: a conservative femoral neck cut; horizontal cup placement (45 degrees); increased anteverted cup placement (20 degrees); use of trial liners; impaction of ceramic pieces; hand placement of the liner; and removal of osteophytes and/or part of the anterior wall of the acetabulum to avoid impingement. Alternate bearing articulations, particularly ceramics, have important technical aspects to be considered at the time of implantation to minimize intraoperative and postoperative complications. To date, there have been no postoperative fractures of the ceramic pieces in any of the completed or ongoing ceramic-on-ceramic investigations by all involved manufacturers. These preliminary results are satisfactory at this time. One can look to the future with cautious optimism.

Periprosthetic infection is an increasingly prevalent and challenging problem in joint reconstruction. We present a technical report of a custom spacer for management of an infected total knee arthroplasty (TKA) and concomitant severe bone loss. The spacer was designed to provide sufficient leg length, soft tissue tension, and limb stability in preparation for ultimate limb reconstruction. This technique and custom spacer serve as an alternative for managing significant bone loss in infected knee arthroplasty.

We report six cases where significant postoperative pain persisted in individuals following arthroscopic surgery augmented with the use of lasers. Subsequent magnetic resonance images showed lesions with signal changes compatible with the diagnosis of osteonecrosis in areas directly addressed with laser energy.

Infection remains a devastating complication of total joint arthroplasty. There have been many significant advances to help identify and reduce the risks of infection over the years. However, when an infection occurs, the management can be complex. This article reviews some of the basic treatment strategies for infected prosthetic replacements.

Femoral stems with the capacity for exuberant bony in-growth, such as hydroxyapatite- or porous-coated stems, pose a challenge in the revision setting if extraction is required. The goal of minimal bone loss is crucial. We present an adjunct technique for the removal of well-fixed femoral stems with the use of Steinman pins.

Core decompression and grafting has been shown to relieve pain and possibly prevent disease progression in patients with symptomatic osteonecrosis (ON) of the hip. However, there is a lack of evidence regarding the management of the asymptomatic hip with femoral head ON. The purpose of this study was to evaluate the outcome of core decompression in the asymptomatic hip with ON. We prospectively followed 37 consecutive patients with MRI confirmed ON of the hips that underwent simultaneous bilateral core decompression and bone grafting. Prior to surgery, only one of the hips was symptomatic, and the main indication for surgical decompression of the asymptomatic side was to prevent disease progression. No hip on the asymptomatic side was staged greater than Steinberg IIB classification. Serial radiographs were followed for evidence of disease progression. Six patients were lost to follow-up prior to two years. The remaining 31 patients were followed for an average of 32.6 months. There were 20 men and 11 women with an average age of 40.6 years. Ten patients with asymptomatic hips at the time of surgical decompression had disease progression requiring THA. The mean time to arthroplasty in this group was 15.1 months. Meanwhile, 13 symptomatic hips at the initial surgery progressed to THA at an average of 12.9 months following core decompression. The proportion of hips requiring conversion to THA was similar between the two groups (p=0.30), and the rate of progression to THA was not significantly faster compared to patients with symptomatic hips who subsequently required THA (p=0.18). Core decompression for asymptomatic ON of the femoral head is unpredictable. Based on our results, asymptomatic ON lesions particularly in the setting of bilateral disease should be closely observed and surgery reserved for when symptoms arise.

Saline-coupled bipolar sealing has shown mixed results in primary arthroplasty. However, this technology has not been studied in infected revision total hip arthroplasty (THA), where morbidity is higher and conventional methods of blood management, such as cell salvage, often cannot be used. This case-matched study of 76 consecutive revision THA for infection included an experimental bipolar sealing group and a control group of conventional electrocautery. Groups were matched for gender, body mass index, American Society of Anesthesiologists classification, and surgery type. Total blood loss, intraoperative blood loss, and perioperative hemoglobin drop were significantly less in the experimental group. In addition, operative time was significantly shorter in the experimental group, which translated into gross savings approximately equal to the cost of the device. The decreases in total blood loss and perioperative hemoglobin decline, along with financial savings, may support the use of bipolar sealing in infected revision THA.

Purpose. To compare the rate and unit of allogeneic blood transfusion in one-stage bilateral total hip arthroplasty (THA) in patients with and without autologous blood reinfusion. Methods. Records of a consecutive series of 43 men and 33 women aged 25 to 83 (mean, 55) years who underwent one-stage sequential bilateral THA by a single surgeon were reviewed. Their risks of cardiopulmonary complications were minimal. At least 4 weeks prior to surgery, 38 of the patients donated 2 units of autologous blood in 2 stages (one to 2 weeks apart). The remaining 38 patients did not donate blood owing to personal preferences or logistical reasons. All pre-donated autologous blood was transfused back to the patients in the recovery room. Estimated blood loss volume, blood salvaged volume, and complications were recorded, as were pre- and post-operative haemoglobin levels. The 2 groups were compared with respect to the rate and unit of allogeneic blood transfusion. Results. The mean estimated blood loss was 939 (SD, 448; range, 200–2500) ml. The mean volume of blood salvaged was 302 (SD, 196; range, 0–850) ml, representing a collection rate of 32%. In patients with and without autologous blood reinfusion, 16 (42%) and 33 (87%) patients received allogeneic blood transfusion of 0.9 and 2.4 units, respectively (pConclusion. Autologous blood reinfusion was effective in reducing the rate and unit of allogeneic blood transfusion in patients undergoing one-stage bilateral THA.

Revision total knee arthroplasty can be complicated by severe patellar bone loss, precluding the use of standard cemented patellar components. This study evaluated the midterm outcomes of porous tantalum (PT) patellar components. Twenty-three PT components were used in 6 men and 17 women (average age, 62 years). All patellae had less than 10-mm residual thickness. The PT shell was secured to host bone, and a 3-peg polyethylene component was cemented onto the shell. In 2 patients, the PT component was sutured directly to extensor mechanism. Average follow-up was 7.7 years (range, 5-10 years). At follow-up, the Knee Society scores for pain and function averaged 82.7 and 33.3, respectively, whereas the mean Oxford knee score was 32.6. Four patients underwent revision surgery. Survivorship was 19 (83%) of 23 patients. Porous tantalum patellar components can provide fixation where severe bone loss precludes the use of traditional implants. Failures were associated with avascular residual bone and fixation of components to the extensor mechanism.

A significant increase in younger patients undergoing total knee arthroplasty raises the theoretical concern for revision secondary to micromotion and fixation failure with cemented components. We prospectively studied 100 consecutive tantalum monoblock uncemented tibial components and 312 concurrent cemented controls. Patients younger than 55 years with adequate bone stock were enrolled. This cementless patient group was younger and had higher preoperative functional status. Prostheses were posterior-substituting uncemented femoral and tibial components with a cemented patellar button. Knee Society pain and function scores and radiographs were obtained, and a cost analysis was performed. Knee Society scores were excellent and equivalent beyond 6 months. There was no significant difference in perioperative blood loss, complication rates, or cost. There was a significant decrease in operative time in the uncemented group. Radiographs revealed no failures of ingrowth at last follow-up. There were 3 uncemented group failures, but none were due to failure of fixation. The use of a porous tantalum tibia at minimum 5 years has yielded promising clinical and radiographic results in a younger patient population.

Capacious diaphyses and poor bone stock in revision arthroplasty can lead to fracture and poor component fixation. Impaction bone grafting can be performed in salvage reconstructions in cases with extensive circumferential bone loss. We present a consecutive series of patients who underwent proximal or distal femoral reconstructions in combination with impaction bone grafting. The average age was 62 years, and the mean follow-up was 36 months (range, 24-84). No revisions were performed for mechanical failure, and radiographs revealed no evidence of implant loosening. No patient complained of end-of-stem thigh pain. There were 3 failures: 1 for periprosthetic fracture, 1 for instability, and 1 for infection. Impaction bone grafting can be used in combination with proximal and distal femoral arthroplasty to successfully manage cases with extensive bone loss after failed hip and knee arthroplasty. The procedure reconstitutes necessary bone stock, improves stress shielding, and provides immediate fixation in capacious canals.

Multiple total knee arthroplasty revisions pose significant surgical challenges, such as bone loss and soft tissue compromise. For patients with bone loss and extensor mechanism insufficiency after total knee arthroplasty, arthrodesis is a treatment option for the avoidance of amputation. However, arthrodesis is both difficult to achieve in situations with massive bone loss and potentially undesirable due to the dramatic shortening that follows. Although intramedullary nailing for knee arthrodesis has been widely reported, this technique has traditionally relied on the achievement of bony union. We report a case of a patient with massive segmental bone loss in which a modular intercalary prosthesis was used for arthrodesis to preserve limb length without bony union.

Infections following hip and knee replacements can compromise the function and durability of arthroplasty. When these infections occur during the immediate postoperative period, irrigation and débridement can be attempted to salvage the implant. Prior studies have reported varying results likely due to lack of consistent inclusion criteria, variations in surgical technique, and lack of uniform treatment protocols.To supplement this literature we determined the rate at which irrigation and débridement and prosthesis retention would control acute periprosthetic infections.We retrospectively reviewed the medical records of 18 patients with acute periprosthetic infections occurring within 28 days after 13 THAs and 5 TKAs. The mean time to reoperation was 19 days (range, 6-28 days) after arthroplasty. Superficial débridements were performed in five cases, and a polyethylene or ball head exchange was performed in the remaining 13 cases when fascial defects were encountered at the time of surgery.We salvaged the prosthesis in four of five patients with superficial irrigation and débridement group and eight of 13 with deep infections. Intraoperative cultures were positive in 83% of cases (n = 15). Five patients (one superficial and four deep) eventually underwent resection arthroplasty. Three patients underwent repeat irrigation and débridement, and one of these three ultimately had resection arthroplasty. Polymicrobial infections were detected in four cases, all failures. The average time to resection was 62 days (range, 12-134 days).Consistent with the literature, success of prosthesis salvage for periprosthetic infections occurring within 28 days after arthroplasty depends on the location, extent, and microbiology of the infection.Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Despite recent advances in cartilage regeneration and restoration procedures, isolated, large, full-thickness cartilage lesions in young patients continue to pose significant challenges to patients and orthopedic surgeons. Treatment options for this difficult problem have traditionally included arthrodesis, osteotomy, osteochondral allograft, and prosthetic reconstruction. We present a case of an adolescent patient with isolated idiopathic lateral tibial chondrolysis treated with a custom ceramic hemi-unicondylar hemiarthroplasty. Preoperatively, a 3-dimensional computed tomography scan of the patient's knee was obtained to begin manufacturing a conforming custom ceramic insert that would articulate between the tibial base plate and the patient's native lateral femoral cartilage. Through a lateral parapatellar approach, the tibial preparation was carried out using the Zimmer M/G unicompartmental knee system (Warsaw, Indiana), and the tibial base plate was cemented into position in the standard fashion. A custom, conforming, prefabricated ceramic insert (CeramTec, Memphis, Tennessee) was then inserted onto the tibial base plate. At 5-year follow-up, this salvage procedure was successful in relieving pain and restoring function in this young patient. There were no signs of implant loosening or lysis. Magnetic resonance imaging of the knee at last follow-up revealed that the cartilage thickness of the patient's lateral femoral condyle remained unchanged. Unicondylar hemiarthroplasty performed in patients with large unipolar lesions in the knee can provide durable and reliable pain relief. Ceramic is a viable material that can be considered for articulation with native cartilage.

There has been some reluctance to perform total hip replacement on younger patients with osteonecrosis because of the poor results reported in the earlier literature. To determine the extent to which advances in surgical technique and prosthesis design have led to improved results, we evaluated 203 total hip replacements performed for osteonecrosis and compared them to 300 performed for degenerative joint disease. The failure rate for all femoral and acetabular components combined was 3.7% (22 of 600), in degenerative joint disease and 10.1% (41 of 406) in osteonecrosis. However, results with the most recently used acetabular component, the noncemented HGP-1, were markedly improved over earlier components in both conditions, with only 1 failure in 235 hips (0.4%). The increased survivorship of THR in osteonecrosis with improved component design and surgical technique is encouraging. Total hip replacement is a good option for patients with advanced stages of osteonecrosis, and similar surgical indications should be used for patients with degenerative joint disease and other disorders.

The purpose of this study is to evaluate the efficacy of trabecular metal (TM) shells and augments in acetabular revisions with significant pelvic bone loss. We retrospectively reviewed 97 cases of consecutive loose total hip arthroplasty with a minimum of Paprosky grade IIA pelvic bone loss treated with a TM revision acetabular component with or without modular augments. The average Harris hip score improved from 55 preoperatively to 76 postoperatively. At the most recent radiographic evaluation, 88 cups demonstrated no lucent lines, 1 cup had lucent lines but remained well fixed, and 8 cups underwent resection arthroplasty for infection. One cup was revised for chronic instability. There were no aseptic failures in this series. Trabecular metal acetabular cups and shells with or without the use of modular augments can be effectively used to revise failed acetabular components in patients with substantial pelvic bone loss.

We present a technique of femoral impaction grafting used for the treatment of periprosthetic femur fractures with severe bone loss after total hip arthroplasty. Seven patients with femoral fractures with compromise of the femoral isthmus were treated with femoral component revision using the impaction grafting bone technique. The average age was 64 years (range, 44-72 years), and 2 patients required mesh augmentation at the time of surgery. The average follow-up for this group of patients was 56 months (range, 39-92 months). Radiographic evaluation revealed healed fractures in all patients and no evidence of implant loosening at a mean of 56 months (range, 39-92 months). There were no cases of infections or dislocations in this series. Impaction grafting technique can be useful in the treatment of periprosthetic femur fractures when bone loss and canal geometry preclude the use of fully coated femoral components.

Total joint arthroplasty is being performed in younger, more active patients, which necessitates improved implant longevity and enhanced component performance. Over the past decade, there has been an increased focus on alternative bearing materials as a potential solution to these issues. Historically, cobalt-chromium has been the material of choice as a bearing surface for both the femoral component in total knee arthroplasty (TKA) and the femoral head articulation in total hip arthroplasty (THA). In recent years, oxidized zirconium (OxZr) has been introduced as a bearing surface with superior resistance to surface roughening, improved frictional characteristics, and excellent biocompatibility as compared with cobalt-chrome. This article demonstrates the use of OxZr as an alternate bearing in the setting of TKA, THA, and hip hemi-arthroplasty based on its biomaterial properties as it applies to polyethylene and native cartilage surface articulation.

Orthopaedic patients frequently require blood transfusions to treat peri-operative anemia. Research in the area of hemoglobin substitutes has been of great interest since it holds the promise of reducing the reliance on allogeneic blood transfusions. The three categories of hemoglobin substitutes are (1) cell-free, extracellular hemoglobin preparations made from human or bovine hemoglobin (hemoglobin-based oxygen carriers or HBOCs); (2) fluorine-substituted linear or cyclic carbon chains with a high oxygen-carrying capacity (perfluorocarbons); and (3) liposome-encapsulated hemoglobin. Of the three, HBOCs have been the most extensively studied and tested in preclinical and clinical trials that have shown success in diminishing the number of blood transfusions as well as an overall favorable side-effect profile. This has been demonstrated in vascular, cardiothoracic, and orthopaedic patients. HBOC-201, which is a preparation of cell-free bovine hemoglobin, has been approved for clinical use in South Africa. These products may well become an important tool for physicians treating peri-operative anemia in orthopaedic patients.

Polyethylene wear and extension of indications of total hip arthroplasty into younger and younger age groups have pushed manufacturers to develop more durable bearing surfaces. Standard polyethylene, the plastic used for the first 3 decades of hip replacement, virtually ceases to exist in its original form. Modifications of the processing, including sterlization in an inert environment and cross-linking, have demonstrated some improvements in wear. Hard-on-hard bearings such as ceramic-on-ceramic and metal-on-metal also have demonstrated extremely low wear. This article reviews the pros and cons of the alternative bearing options available to assist in the proper bearing selection for a particular patient.

We present a prospective study of impaction grafting using collared textured stems in femurs with massive defects (defined as requiring >150 cm 3 of cancellous allograft). Eighteen hips were followed for a minimum of 2 years. Average Harris hip scores increased from 50 preoperatively to 83 at most recent follow-up. Seventeen hips were functioning well at the time of most recent follow-up and exhibited no stem subsidence or aseptic loosening. One hip was associated with visible subsidence and required further revision. Single-photon emission computed tomography analyses performed at an average of 37 months indicated active graft reorganization in all cases studied. Impaction allografting with collared textured stems for massive defects demonstrates good intermediate-term clinical results and may be a useful alternative to allograft stem composites and megaprostheses.

The purpose of this study was to estimate the incidence of hospital-acquired pressure ulcers among elderly patients hospitalized for hip fracture surgery and to identify extrinsic factors that are associated with increased risk. We conducted a secondary analysis of data abstracted from medical records at 20 hospitals in Pennsylvania, Texas, New Jersey, and Virginia. Participants were patients aged 60 years and older admitted with hip fracture to the study hospitals between 1983 and 1993. The incidence of hospital-acquired pressure ulcers was 8.8% (95% confidence interval 8.2%-9.4%). After adjusting for confounding variables, longer wait before surgery, intensive care unit stay, longer surgical procedure, and general anesthesia were significantly associated with higher pressure ulcer risk. Extrinsic factors may be important markers for high pressure ulcer risk in hospitalized hip fracture patients. Although it is not possible to eliminate factors such as requiring an intensive care unit stay or having a long surgical procedure, it may be possible to develop interventions that minimize pressure ulcer risk in patients who experience these factors.

Background: Adherent bone marrow stromal cells are inducible osteoprogenitors, giving rise to cells expressing osteoblast markers including alkaline phosphatase, osteopontin, osteocalcin, and bone sialoprotein. However, the potency of inducers varies in a species-specific manner. Glucocorticoids such as dexamethasone induce alkaline phosphatase activity in both human and rat mesenchymal stem cells, while mouse bone marrow stromal cells are refractory to dexamethasone-induced alkaline phosphatase activity. In contrast, BMP induces alkaline phosphatase activity in both mouse and rat bone marrow stromal cells, while BMP effects on human bone marrow stromal cells are poorly characterized. Methods: Bone marrow samples were isolated from patients undergoing hip replacement. Mononuclear marrow cells were cultured and grown to confluence without or with 10 -7 M dexamethasone. Cells from each isolate were passaged into medium containing 100 μg/mL ascorbate phosphate and treated with dexamethasone, 100 ng/mL BMP, or no inducer. At day 6, alkaline phosphatase activity was assayed, and RNA was prepared for mRNA analyses by real-time polymerase chain reaction. Results: Bone marrow stromal cells from twenty-four of twenty-six patients showed no significant osteogenic response to BMP-2, 4, or 7 as determined by alkaline phosphatase induction. However, BMPs induced elevated levels of other genes associated with osteogenesis such as bone sialoprotein and osteopontin as well as BMP-2 and noggin. If primary cultures of human bone marrow stromal cells were pretreated with dexamethasone, BMP-2 treatment of first-passage cells induced alkaline phosphatase in approximately half of the isolates, and significantly greater induction was seen in cells from males. Dexamethasone treatment, like BMP treatment, also increased expression of the BMP-binding protein noggin. Conclusions: Most human femur bone marrow stromal cell samples appear incapable of expressing elevated alkaline phosphatase levels in response to BMPs. Since BMP treatment induced expression of several other BMP-regulated genes, the defect in alkaline phosphatase induction is presumably not due to impaired BMP signaling. We hypothesize that the mechanism by which BMPs modulate alkaline phosphatase expression is indirect, involving a BMP-regulated transcription factor for alkaline phosphatase expression that is controlled differently in humans and rodents. Clinical Relevance: We suggest that the relative insensitivity of alkaline phosphatase to BMP induction in human bone marrow stromal cells may contribute to the variation in efficacy reported with BMP in clinical settings.

Background The efficacy of saline-coupled bipolar sealing devices in joint arthroplasty is uncertain, and the utility in simultaneous bilateral total knee arthroplasty (TKA) has not been reported. Methods This study compares the use of bipolar sealing and conventional electrocautery in 71 consecutive patients. The experimental and control groups were matched for age, sex, body mass index, American Society of Anesthesiologists (ASA) classification, and preoperative hemoglobin. Variables of interest included blood loss, transfusion requirements, and operative characteristics. Results In comparison to patients treated with conventional electrocautery, those treated with the bipolar sealer were 35% less likely to require transfusion. The median number of transfusions per case was also significantly lower in the experimental group. Hemoglobin change, total blood loss, and length of stay were not significantly different between the groups. The experimental group had longer operative times. Conclusions Bipolar sealing shows promise as a blood loss reduction tool in simultaneous bilateral TKA. The marginal savings attributed to reduced transfusion rates with use of the bipolar sealer did not exceed the additional per-case expense of using the device. The decision to use the device with the goal of less blood loss must come with the additional expense associated with its use.

This retrospective study compared the results of revision total hip arthroplasty (THA) In patients with avascular necrosis to patients with osteoarthritis. Twenty-two revision THAs (34 components) in 19 patients with avascular necrosis were compared with 35 revision THAs (55 components) in 31 patients with osteoarthritis. All of the procedures were performed by a single surgeon between 1981 and 1994, and all patients had a minimum of 2 years of follow-up. At the time of revision surgery, the average age was 54 years for the avascular necrosis patients and 67 years for the osteoarthritis patients (P=.002). Clinical and radiographic follow-up was performed for an average of 7 years (range: 2-12 years). Six (18%) components in the avascular necrosis group and nine (16%) components in the osteoarthritis group required re-revision for aseptic loosening an average of 7 years after the original revision (range: 2-11 years). Statistical analysis demonstrated no significant difference between the two groups in regard to the incidence of failure, time to failure, Harris Hip Score, and radiographic appearance. Contrary to expectations derived from the literature on primary THA, no difference was found between the outcome and survivorship of revision THA in patients with avascular necrosis and patients with osteoarthritis, despite a significant difference in age.

We evaluated the influence of the expertise of the technician on the accuracy of compression ultrasonography as a screening test to detect postoperative deep venous thrombosis in patients who had had primary or revision arthroplasty of the hip or the knee. The study was performed in two phases on two groups of patients who were evaluated with both compression ultrasonography and conventional venography. All of the patients received prophylaxis for deep venous thrombosis. In the first phase of the study, adequate venograms and ultrasonograms were made for 126 extremities (121 patients). Venography demonstrated seven thrombi in the proximal veins. Only three ultrasonograms were considered positive. Ultrasonography had a sensitivity of 0 per cent because none of the seven proximal thrombi identified with venography were detected with ultrasonography. Three ultrasonograms were false-positive (that is, the ultrasonogram was positive and the venogram was negative), so the specificity was 97 per cent. The accuracy of compression ultrasonography was 92 per cent. Both tests were performed on a second group of eighty-seven extremities (eighty-four patients). Proximal clots were detected with venography in five extremities. The ultrasonogram was positive for seven extremities, including the five in which a clot had been identified with venography. There were no false-negative and two false-positive results. In this phase of the study, ultrasonography had a sensitivity of 100 per cent, a specificity of 98 per cent, and an accuracy of 98 per cent. The only difference that was identified between the two groups of patients was the experience of the ultrasonography technician. It appears that the reliability of compression ultrasonography is directly dependent on the experience of the technician.

NEUROLOGIC complications of knee and hip arthroplasty range from mild delirium to coma and death. 1 The pathogenesis and operative events that lead to acute neurologic injury during joint arthroplasty are not completely understood but are thought to be a consequence of the fat embolism syndrome. 1-3 The syndrome often is accompanied by pulmonary, circulatory, hematologic, and neurologic derangement. According to one hypothesis, procedures that increase intramedullary pressure promote the entry of marrow fat or other debris into the central venous circulation through the medullary veins. 3,4 These emboli accumulate within the lung, causing increases in the pulmonary vascular resistance and pulmonary artery pressure. The consequent increase in right atrial and pulmonary artery pressures favor right-to-left shunt flow via a patent foramen ovale (atrial septal defect) or intrapulmonary shunt increasing the risk of paradoxical cerebral embolization. In the following report, intraoperative hemodynamic monitoring, carotid artery ultrasonography, and electroencephalography (EEG) were used to detect the sequence of operative events that led to paradoxical cerebral embolization causing fatal neurologic injury during bilateral knee arthroplasty.

Carotid hemorrhage secondary to peritonsillar abscess occurs infrequently today because of the effectiveness of antibiotic therapy. When it does occur, however, emergency physicians unfamiliar with such a complication may have difficulty making its diagnosis and instituting appropriate therapy. Prevention is the easiest way to treat septic erosion. Abscesses are treated best with penicillin or, in the allergic patient, clindamycin followed by incision and drainage. Once the abscess has eroded into the carotid artery, it usually must be tied off to control the subsequent massive bleeding.

Ceramic bearings have been used extensively in total hip arthroplasty, both in ceramic-on-polyethylene and in ceramic-on-ceramic articulations. Ceramic articulations in total hip arthroplasties offer the advantage of lower wear rates compared to the standard metal-polyethylene coupling. In total knee arthroplasty, few data have examined the application of ceramic bearings. The long-term failure mode of total knee arthroplasties is related to wear and failure of the polyethylene in the articulation. Wear data from knee simulators and in vitro investigations suggest ceramics may offer a superior countersurface in total knee bearings through decreased polyethylene wear rates and a lower incidence of long-term failures associated with wear. This article reviews the existing data related to the application of ceramic biomaterials in total knees and evaluates the role ceramic surfaces may have in extending the longevity of total knee arthroplasty.