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Background: Corrosion at the modular head-neck junction of the femoral component in total hip arthroplasty has been identified as a potential concern, although symptomatic adverse local tissue reactions secondary to corrosion have rarely been described.Methods: We retrospectively reviewed the records of ten patients with a metal-on-polyethylene total hip prosthesis, from three different manufacturers, who underwent revision surgery for corrosion at the modular head-neck junction.Results: All patients presented with pain or swelling around the hip, and two patients presented with recurrent instability. Serum cobalt levels were elevated prior to the revision arthroplasty and were typically more elevated than were serum chromium levels. Surgical findings included large soft-tissue masses and surrounding tissue damage with visible corrosion at the femoral head-neck junction; the two patients who presented with instability had severe damage to the hip abductor musculature. Pathology specimens consistently demonstrated areas of tissue necrosis. The patients were treated with debridement and a femoral head and liner exchange, with use of a ceramic femoral head with a titanium sleeve in eight cases. The mean Harris hip score improved from 58.1 points preoperatively to 89.7 points at a mean of 13.0 months after the revision surgery (p=0.01). Repeat serum cobalt levels, measured in six patients at a mean of 8.0 months following revision, decreased to a mean of 1.61 ng/mL, and chromium levels were similar to prerevision levels. One patient with moderate hip abductor muscle necrosis developed recurrent instability after revision and required a second revision arthroplasty.Conclusions: Adverse local tissue reactions can occur in patients with a metal-on-polyethylene bearing secondary to corrosion at the modular femoral head-neck taper, and their presentation is similar to the adverse local tissue reactions seen in patients with a metal-on-metal bearing. Elevated serum metal levels, particularly a differential elevation of serum cobalt levels with respect to chromium levels, can be helpful in establishing this diagnosis. [ABSTRACT FROM AUTHOR]

The immune system plays a dynamic role in physiological and pathogenic bone remodeling. Macrophage-, stromal-, and lymphocyte-derived cytokines may induce the activation or inhibition of bone cells and their precursors and cause bone deposition or bone resorption. Progress has been made in understanding the immune and bone systems in the field of osteoimmunology, but understanding how inflammatory responses triggered by orthopedic implant wear affect osteolysis remains a complex area of study. Key proinflammatory mediators, such as receptor activator of nuclear factor kB ligand, interleukin (IL)-1b, IL-6, tumor necrosis factor alpha, cyclooxygenase-alpha, and prostaglandin E2, play a significant role in osteoclast precursor recruitment, differentiation, and activation. The role of IL-17 is of particular interest. [ABSTRACT FROM AUTHOR]

ABSTRACT: More than 1 million total joint arthroplasties (TJAs) are performed in the United States each year, and much higher demand is projected. Most TJAs are successful, but aseptic loosening of implants remains a problem that limits long-term success. Aseptic osteolysis, an inflammatory reaction, occurs in up to 10% of patients at 10 years postsurgery. Bone loss around the implant results in pain, premature loosening, and revision. Advances have been made in understanding the inflammatory bone loss at the molecular and cellular levels. Treatment options, ranging from testing preexisting conditions of metal allergy to general management of inflammation to selective blocking of cellular mediators for hindering of implant debris-induced osteolysis promise to help mitigate the problem of inflammatory bone loss. [ABSTRACT FROM AUTHOR]

A technology assessment is a literature-based research project that seeks to determine whether a medical device, drug, procedure, or biologic is effective or to summarize literature on a given technology. A well-conducted assessment is a form of secondary research that employs the same steps used in primary research studies (ie, well-designed clinical trials). The primary difference is that in technology assessment the investigator does not collect the raw data. Rather, (s)he must use data collected by someone else. Nevertheless, a well-designed assessment, like a well-designed study, employs the scientific method, which is a method designed to combat bias. When there is little available information, such as with new technologies, unbiased examinations can typically show that enthusiasm for that technology is not backed by much data. When there is more information, assessments can not only determine whether a technology is effective, but also how effective it is. Technology assessments can provide busy orthopaedic surgeons (who do not have the time to keep up with and critically evaluate current literature) with succinct information that enables them to rapidly determine what is and what is not known about any given medical technology. [ABSTRACT FROM AUTHOR]

We previously reported the seven and fifteen-year results of the use of a porous-coated acetabular metal shell inserted without cement in a consecutive series of 204 primary total hip arthroplasties. In the present study, we evaluated the longer-term outcomes of these arthroplasties at a minimum follow-up time of twenty years. One hundred and fourteen (92%) of the 124 hips available for study had retained the original acetabular metal shell. A total of five acetabular components had been revised for aseptic loosening or had radiographic evidence of definite loosening. Fourteen hips with well-fixed acetabular shells required a change of the modular acetabular liner because of excessive wear and/or for the treatment of osteolysis, and liner changes have been recommended for another eight hips. The twenty-year rate of survival of the metal shell, with failure defined as revision because of loosening or radiographic evidence of loosening, was 96% (95% confidence interval, 94% to 98%). Cementless acetabular reconstruction continues to provide durable fixation at twenty years postoperatively. Wear-related complications continue to be the major mode of failure. [ABSTRACT FROM AUTHOR]

Particulate and ionic debris resulting from in vivo degradation of total joint replacement components are recognized as major factors limiting the longevity of the joint reconstruction and the overall success of the procedure. Particulate and ionic wear and corrosion debris have been associated with a locally aggressive biologic response that can lead to synovitis, periprosthetic bone loss, and aseptic loosening of the implants. Furthermore, concerns exist regarding the systemic dissemination of prosthetic debris, including potential effects resulting from end-organ retention. The long-term success of total disc arthroplasty may well depend, at least in part, on the ability to minimize implant debris generation and the subsequent local and systemic response. [ABSTRACT FROM AUTHOR]

We previously reported our results at a minimum of three and seven years after use of a porous-coated acetabular metal shell in a consecutive series of 138 revision total hip arthroplasties. The current report presents the longer-term outcomes of these procedures, at fifteen to nineteen years postoperatively. A total of twenty metal shells (14%) underwent repeat revision. Seven of the repeat revisions were performed because of recurrent dislocation, seven were done at the time of femoral revision surgery, and six were done because of infection. Nineteen of the revised shells were well fixed, and one was aseptically loose. Of the sixty-seven hips in which the acetabular component survived for more than fifteen years after the index operation, two (3%) required a change of the modular acetabular liner because of wear or osteolysis. Nine (16%) of the fifty-seven hips with at least fifteen years of radiographic follow-up had an osteolytic lesion of >1 cm in diameter. The fifteen-year survival rate of the metal shells, with failure defined as revision because of loosening or as radiographic evidence of loosening, was 97%. Revision total hip arthroplasty with this cementless acetabular component has been followed by excellent component survivorship at fifteen years; the most common reasons for repeat revision were recurrent dislocation and infection. [ABSTRACT FROM AUTHOR]

Background: There is a renewed interest in unicompartmental knee arthroplasty. The present report describes the minimum ten-year results associated with a unicompartmental knee arthroplasty design that is in current use.Methods: Sixty-two consecutive unicompartmental knee arthroplasties that were performed with cemented modular Miller-Galante implants in fifty-one patients were studied prospectively both clinically and radiographically. All patients had isolated unicompartmental disease without patellofemoral symptoms. No patient was lost to follow-up. Thirteen patients (thirteen knees) died after less than ten years of follow-up, leaving thirty-eight patients (forty-nine knees) with a minimum of ten years of follow-up. The average duration of follow-up was twelve years.Results: The mean Hospital for Special Surgery knee score improved from 55 points preoperatively to 92 points at the time of the final follow-up. Thirty-nine knees (80%) had an excellent result, six (12%) had a good result, and four (8%) had a fair result. At the time of the final follow-up, thirty-nine knees (80%) had flexion to at least 120 degrees . Two patients (two knees) with well-fixed components underwent revision to total knee arthroplasty, at seven and eleven years, because of progression of patellofemoral arthritis. At the time of the final follow-up, no component was loose radiographically and there was no evidence of periprosthetic osteolysis. Radiographic evidence of progressive loss of joint space was observed in the opposite compartment of nine knees (18%) and in the patellofemoral space of seven knees (14%). Kaplan-Meier analysis revealed a survival rate of 98.0% +/- 2.0% at ten years and of 95.7% +/- 4.3% at thirteen years, with revision or radiographic loosening as the end point. The survival rate was 100% at thirteen years with aseptic loosening as the end point.Conclusions: After a minimum duration of follow-up of ten years, this cemented modular unicompartmental knee design was associated with excellent clinical and radiographic results. Although the ten-year survival rate was excellent, radiographic signs of progression of osteoarthritis in the other compartments continued at a slow rate. With appropriate indications and technique, this unicompartmental knee design can yield excellent results into the beginning of the second decade of use. [ABSTRACT FROM AUTHOR]

Background: Total hip replacements with metal-on-metal bearings are frequently implanted in young, active patients. The relationship between patient activity and cobalt and chromium ion levels has not been investigated, to our knowledge.Methods: Seven patients with well-functioning metal-on-metal bearing hip prostheses and one control subject (no implants), all with normal renal function, were monitored during a two-week-long activity protocol. Lower-extremity activity was continuously assessed with use of a computerized, two-dimensional accelerometer. During the first week, the subjects were requested to limit physical activity. The subjects then completed an hour-long treadmill test followed by a week in which they were encouraged to be as physically active as practically possible. Serum levels of cobalt and chromium ions and urine levels of chromium were assessed at ten time-points during these two weeks.Results: Regardless of activity, the serum ion levels for a given patient were essentially constant and no correlation was found between patient activity and serum levels of cobalt or chromium, or urine levels of chromium. A mean increase in activity of 28% during the week of high-intensity activity was associated with a mean decrease of 2.7% in the serum cobalt level and a mean increase of 2.0% in the serum chromium level. During the treadmill test, a mean increase in activity of 1621% was associated with a mean increase of 3.0% in the serum cobalt level and a mean increase of 0.8% in the serum chromium level. These results fall within the variability for the measurement accuracy of these tests.Conclusions: For these patients, serum cobalt and chromium ion levels were not acutely affected by patient activity. Periodic measurements of serum ion levels could be used to monitor the tribologic (lubrication, friction, and wear) performance of a metal-on-metal bearing without adjusting for patient activity. Additional research is needed into the kinetics of ion production, transport, and excretion. [ABSTRACT FROM AUTHOR]

Background: Disruption of the extensor mechanism is an uncommon but catastrophic complication of total knee arthroplasty. We evaluated two techniques of reconstructing a disrupted extensor mechanism with use of an extensor mechanism allograft following total knee arthroplasty.Methods: Twenty consecutive reconstructions with use of an extensor mechanism allograft consisting of the tibial tubercle, patellar tendon, patella, and quadriceps tendon were performed. The first seven reconstructions (Group I) were done with the allograft minimally tensioned. The thirteen subsequent procedures (Group II) were performed with the allograft tightly tensioned in full extension. All surviving allografts were evaluated clinically and radiographically after a minimum duration of follow-up of twenty-four months.Results: All of the reconstructions in Group I were clinical failures, with an average postoperative extensor lag of 59 degrees (range, 40 degrees to 80 degrees ) and an average postoperative Hospital for Special Surgery knee score of 52 points. All thirteen reconstructions in Group II were clinical successes, with an average postoperative extensor lag of 4.3 degrees (range, 0 degrees to 15 degrees ) (p < 0.0001) and an average Hospital for Special Surgery score of 88 points. Postoperative flexion did not differ significantly between Group I (average, 108 degrees ) and Group II (average, 104 degrees ) (p = 0.549).Conclusions: The results of reconstruction with an extensor mechanism allograft after total knee arthroplasty depend on the initial tensioning of the allograft. Loosely tensioned allografts result in a persistent extension lag and clinical failure. Allografts that are tightly tensioned in full extension can restore active knee extension and result in clinical success. On the basis of the number of knees that we studied, there was no significant loss of flexion. Use of an extensor mechanism graft for the treatment of a failure of the extensor mechanism will be successful only if the graft is initially tensioned tightly in full extension.Level Of Evidence: Therapeutic study, Level III-2 (retrospective cohort study). See Instructions to Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Second-generation cementless femoral components were designed to provide more reliable ingrowth and to limit distal osteolysis by incorporating circumferential proximal ingrowth surfaces. We examined the eight to eleven-year results of total hip arthroplasty with a cementless, anatomically designed femoral component and a cementless hemispheric acetabular component.Methods: Ninety-two consecutive primary total hip arthroplasties with implantation of a femoral component with a circumferential proximal porous coating (Anatomic Hip) and a cementless hemispheric porous-coated acetabular component (Harris-Galante II) were performed in eighty-five patients. These patients were prospectively followed clinically and radiographically. Six patients (seven hips) died and five patients (seven hips) were lost to follow-up, leaving seventy-four patients (seventy-eight hips) who had been followed for a mean of ten years (range, eight to eleven years). The mean age at the time of the arthroplasty was fifty-two years.Results: The mean preoperative Harris hip score of 51 points improved to 94 points at the time of final follow-up; 86% of the hips had a good or excellent result. Thigh pain was reported as mild to severe after seven hip arthroplasties. No femoral component was revised for any reason, and none were loose radiographically at the time of the last follow-up. Two hips underwent acetabular revision (one because of dislocation and one because of loosening). Kaplan-Meier survivorship analysis was performed with revision or loosening of any component as the end point. The ten-year survival rate was 96.4% +/- 2.1% for the total hip prosthesis, 100% for the femoral component, and 96.4% +/- 2.1% for the acetabular component. Radiolucencies adjacent to the nonporous portion of the femoral component were seen in sixty-eight (93%) of the -seventy-three hips with complete radiographic follow-up. Femoral osteolysis proximal to the lesser trochanter was noted in four hips (5%). No osteolysis was identified distal to the lesser trochanter. Periacetabular osteolysis was identified in twelve hips (16%). Five patients underwent exchange of the acetabular liner because of polyethylene wear.Conclusions: This second-generation cementless, anatomically designed femoral component provided excellent clinical and radiographic results with a 100% survival rate at ten years. The circumferential porous coating of this implant improved ingrowth and prevented distal osteolysis at a mean of ten years after the arthroplasty. [ABSTRACT FROM AUTHOR]

Background: Although initial reports on posterior cruciate ligament-retaining total knee arthroplasty in patients with rheumatoid arthritis have been encouraging, a high rate of late instability necessitating revision has been reported recently. The purpose of the present prospective study was to analyze the results of posterior cruciate ligament-retaining total knee arthroplasty in patients with rheumatoid arthritis.Methods: Seventy-two posterior cruciate ligament-retaining total knee arthroplasties in fifty-one patients with rheumatoid arthritis were studied prospectively. All procedures were performed with the Miller-Galante I prosthesis. Eighteen patients (twenty-four knees) died before the eight-year follow-up and one patient (two knees) was lost to follow-up, leaving forty-six knees (thirty-two patients) for review. These forty-six knees were evaluated clinically (with particular attention to posterior instability) and radiographically at annual intervals for a mean of 10.5 years (range, eight to fourteen years).Results: Forty-four (95%) of forty-six knees had a good or excellent result at a mean of 10.5 years. However, nine (13%) of the original seventy-two knees had revision of the implant, with six of the revisions performed because of failure of a metal-backed patellar component. The rate of survival at ten years was 93% 4% with femoral or tibial revision for any reason as the end point and 81% 5% with any reoperation as the end point. There was no aseptic loosening in any knee. Posterior instability was identified clinically and/or radiographically in two (2.8%) of the original seventy-two knees; both unstable knees were in the same patient.Conclusion: Posterior cruciate ligament-retaining total knee arthroplasty yielded satisfactory clinical and radiographic results in patients with rheumatoid arthritis at intermediate-term follow-up (mean, 10.5 years). Therefore, we believe that it remains an excellent treatment option for these patients. [ABSTRACT FROM AUTHOR]

Background: Intraoperative disruption of the medial collateral ligament during total knee arthroplasty is an uncommon complication that is frequently treated by implanting a prosthesis with varus-valgus constraint. To our knowledge, no data have been published on primary repair or reattachment of the medial collateral ligament and implantation of a minimally constrained posterior-stabilized or cruciate-retaining prosthesis. This retrospective study evaluates the hypothesis that satisfactory clinical results, at a minimum of two years, can be achieved with immediate repair or reattachment of the medial collateral ligament and without a constrained total knee prosthesis.Methods: Of 600 knees treated with primary total knee arthroplasty, sixteen (in fourteen patients) sustained either a midsubstance disruption of the medial collateral ligament or an avulsion of the ligament from bone during the procedure. Preoperatively, all patients had either neutral or varus alignment and an intact medial collateral ligament. Midsubstance tears were treated with direct primary repair, and avulsions of the ligament off the tibia or femur were treated with suture-anchor reattachment to bone. All patients wore a hinged knee brace, with no limit to the range of motion, for six weeks postoperatively. Clinical and radiographic data were gathered prospectively as part of a database that was ongoing throughout the period of study; the cohort of patients was assembled retrospectively by searching that database.Results: No patients were lost to follow-up. The mean duration of follow-up was forty-five months (range, twenty-four to ninety-five months). The Hospital for Special Surgery knee scores increased from a mean of 47 points (poor) preoperatively to a mean of 93 points (excellent) at the time of final follow-up. On physical examination, no patient had a Hospital for Special Surgery score in the fair or poor range and all patients had regained normal stability in the coronal plane both at full extension and at 30 degrees of flexion. No patient required knee-bracing beyond the initial six-week postoperative period. The range of motion at the time of final follow-up averaged 108 degrees (range, 85 degrees to 125 degrees ), although one knee required manipulation under anesthesia to obtain a satisfactory range of motion. No arthroplasties required revision. Radiographic examination demonstrated appropriate limb alignment in all patients at the time of final follow-up.Conclusions: Intraoperative disruption of the medial collateral ligament can be treated with primary repair or reattachment of the ligament to bone and postoperative bracing with good results; this avoids the potential disadvantages associated with the use of varus-valgus constrained implants. [ABSTRACT FROM AUTHOR]

Osteoarthritis is the most common form of arthritis, affecting millions of people in the United States. It is a complex disease whose etiology bridges biomechanics and biochemistry. Evidence is growing for the role of systemic factors, such as genetics, diet, estrogen use, and bone density, and local biomechanical factors, such as muscle weakness, obesity, and joint laxity. These risk factors are particularly important in the weight-bearing joints, and modifying them may help prevent osteoarthritis-related pain and disability. Major advances in management to reduce pain and disability are yielding a panoply of available treatments ranging from nutriceuticals to chondrocyte transplantation, new oral anti-inflammatory medications, and health education. This article is part 2 of a two-part summary of a National Institutes of Health conference that brought together experts in osteoarthritis from diverse backgrounds and provided a multidisciplinary and comprehensive summary of recent advances in the prevention of osteoarthritis onset, progression, and disability. Part 2 focuses on treatment approaches; evidence for the efficacy of commonly used oral therapies is reviewed and information on alternative therapies, including nutriceuticals and acupuncture, is presented. Biomechanical interventions, such as exercise and bracing, and behavioral interventions directed toward enhancing self-management are reviewed. Current surgical approaches are described and probable future biotechnology-oriented approaches to treatment are suggested. [ABSTRACT FROM AUTHOR]

Background: The importance of particles generated by wear and corrosion of joint replacement prostheses has been understood primarily in the context of the local effects of particle-induced periprosthetic osteolysis and aseptic loosening. We studied dissemination of wear particles in patients with total hip and knee replacement to determine the prevalence of and the histopathological response to prosthetic wear debris in the liver, spleen, and abdominal para-aortic lymph nodes.Methods: Postmortem specimens from twenty-nine patients and biopsy specimens from two living patients with a failed replacement were analyzed. Specimens of tissue obtained from the cadavera of fifteen patients who had not had a joint replacement served as controls. The concentration of particles and the associated tissue response were characterized with the use of light microscopy of stained histological sections. Metallic particles were identified by electron microprobe analysis. Polyethylene particles were studied with the use of oil-red-O stain and polarized light microscopy. The composition of polyethylene particles was confirmed in selected cases by Fourier transform infrared spectroscopy and hot-stage thermal analysis. Twenty-one of the patients studied post mortem had had a primary total joint replacement. Eleven of them had had a hip prosthesis for a mean of sixty-nine months (range, forty-three to 171 months), and ten had had a knee replacement for a mean of eighty-four months (range, thirty-one to 179 months). The other eight patients studied post mortem had had a hip replacement in which one or more components had loosened and had been revised. The mean time between the initial arthroplasty and the time of death was 174 months (range, forty-seven to 292 months), and the mean time between the last revision procedure and the time of death was seventy-one months (range, one to 130 months).Results: Metallic wear particles in the liver or spleen were more prevalent in patients who had had a failed hip arthroplasty (seven of eight) than in patients who had had a primary hip (two of eleven) or knee replacement (two of ten). The principal source of wear particles in the majority of these patients involved secondary nonbearing surfaces rather than wear between the two primary bearing surfaces as intended. In one living patient, dissemination of titanium alloy particles from a hip prosthesis with mechanical failure was associated with a visceral granulomatous reaction and hepatosplenomegaly, which required operative and medical treatment. Metallic wear particles were detected in the paraaortic lymph nodes in 68 percent (nineteen) of the twenty-eight patients with an implant from whom lymph nodes were available for study. In 38 percent (eleven) of all twenty-nine patients with an implant who were studied post mortem, metallic particles had been further disseminated to the liver or spleen, where they were usually found within small aggregates of macrophages occurring as infiltrates without apparent pathological importance. Polyethylene particles elicited a similar response. They were identified in the paraaortic lymph nodes of 68 percent (nineteen) of the twenty-eight patients and the liver or spleen of 14 percent (four) of the twenty-nine patients. The majority of the disseminated wear particles were less than one micrometer in size. Currently available methods lack the sensitivity and specificity necessary to detect very low concentrations of submicrometer polyethylene particles and probably underestimated the prevalence of polyethylene wear debris in the liver and spleen.Conclusions: In this study, systemic distribution of metallic and polyethylene wear particles was a common finding, both in patients with a previously failed implant and in those with a primary total joint prosthesis. The prevalence of particles in the liver or spleen was greater after reconstructions with mechanical failure. (ABSTRACT TRUNCATED) [ABSTRACT FROM AUTHOR]