Metal levels in cemented total hip arthroplasty. A comparison of well-fixed and loose implants.

In a prospective study, synovial fluid metal levels from stainless steel, cobalt-chromium, and titanium-alloy cemented total hip implants were measured. There were 37 well-fixed and 44 loose hip arthroplasties. Tissue-metal levels were quantitated in the cases revised for loosening. Retrieval analysis for implant wear was performed. Synovial fluid analysis showed a fivefold increase in metal levels of loose compared with well-fixed stainless steel implants. There was a sevenfold increase in metal levels of loose compared with well-fixed cobalt-chromium implants. There was a 21-fold increase in metal levels of loose compared with well-fixed titanium-alloy (Ti-6Al-4V) implants. Tissue-metal levels from revised cobalt-chromium implants averaged 45 micrograms/g dry tissue weight compared to 4,470 micrograms/g dry tissue weight from revised titanium-alloy implants, a 100-fold increase. Implant retrieval analysis showed severe burnishing and scratching in all titanium-alloy femoral heads and extensive burnishing and scratching in the majority of the femoral stems. Well-fixed cemented implants have similar low synovial fluid metal levels. However, when loosening of implants occurs, titanium-alloy implants release disproportionate levels of metal into synovial fluid and local tissues compared to stainless steel or cobalt-chromium.     

Human monocyte/macrophage response to cobalt-chromium corrosion products and titanium particles in patients with total joint replacements

The responses of human peripheral blood monocytes of 10 normal volounteers and 14 patients with total hip replacements to particles of commercially pure titanium and chromium orthphosphate (a corrosion product from cobalt-chromium alloy implants) were studied. In addition, these phagocytosable particles were added to cultured mononuclear cells isolated from the interfacial membrane of 14 patients with failed implants. Peripheral blood monocytes from patients who had had a total hip replacement produced significantly higher levels of interleukin-1 (both interleukin-1α and interleukin-1β) and prostaglandin E₂ follwing particulate stimulation than those from normal volunteers. Supernatants from both titanium and chromium orthophosphate-stimulated peripheral blood monocytes from the volunteers and patients with total hip replacement induced bone resorption (assayed in organ cultures of newborn mouse calvariae)and the proliferation of human fibroblasts. The levels of bone resorption were significantly higher (p < 0.05) in patients with implants that in normal volunteers. There were no significant differences in the responses of cells between patients with focal osteolysis and those without osteolysis. Interfacial membrane mononuclear cells also produced high levels of interleukin-1α, interleukin-1β, and prostaglandin E₂ and expressed bone resorptive activities following stimulation with either titanium or chromium orthophosphate. More importantly, interfacial membrane mononuclear cells “spontaneously” produced high levels of prostaglandin E₂ that were comparable with the response of peripheral blood monocytes stimulated with particulate wear debris. The clinical relevance of this study is 2-fold. First, mononuclear cells from patients with total hip replacement were some-how “sensitized” to metal particles in comparison with mononuclear cells from individuals without an implant. Second, the chromium orthophosphate corrosion product was a potent macrophage/monocyte activator and may contribute to macrophage-mediated osteolysis and aseptic loosening.     

The pathogenesis of loosening of total hip arthroplasties. The production of factors by periprosthetic tissues that stimulate in vitro bone resorption

The production of factors capable of stimulating bone resorption in the newly formed periprosthetic capsule and in the bone-cement membrane obtained from patients reoperated due to aseptic loosening of cemented total hip prostheses was studied using organ culture techniques. Addition of culture media conditioned by membranes from six patients and bone-cement membranes from two patients to the mouse calvarial cultures resulted in a significantly increased release of calcium. The effect of capsule-conditioned media on calcium release was dose- and time-dependent and significantly reduced by the osteoclast inhibitor of calcitonin. Histologic analysis of bones at the end of the culture period showed that capsule-conditioned media enhanced the breakdown of mineralized bone and increased the number of osteoclasts. The observations showed that newly formed periprosthetic tissues from patients with loose total hip arthroplasties (THAs) can produce one or several factors that stimulate bone resorption in vitro by an osteoclast-mediated mechanism. Not only mechanical failure but also biologic reactions in the periprosthetic tissues eventually lead to osteoclast activation and may contribute to the loosening of THAs.     

Isoelastic uncemented hip arthroplasty--early experience

With the increasing failure rae with time of cemented total hip arthroplasty there is a growing interest in uncemented total joint replacement. This review of 88 Isoelastic total hip arthroplasties, and 28 Isoelastic hemiarthroplasties suggests that this implant gives results comparable with cemented total hip arthroplasty at a similar time. The Isoelastic hip replacement system uses uncemented components that have been designed to closely approximate the biomechanical properties of the bone into which they are implanted. The surgical technique is demanding, and orthopaedic surgeons who anticipate using uncemented implants should receive thorough training before embarking on an implantation.     

ISOELASTIC UNCEMENTED HIP ARTHROPLASTY—EARLY EXPERIENCE

With the increasing failure rate with time of cemented total hip arthroplasty there is a growing interest in uncemented total joint replacement. This review of 88 isoelastic total hip arthroplasties, and 28 isoelastic hemiarthroplasties suggests that this implant gives results comparable with cemented total hip arthroplasty at a similar time. The isoelastic hip replacement system uses uncemented components that have been designed to closely approximate the biomechanical properties of the bone into which they are implanted. The surgical technique is demanding, and orthopaedic surgeons who anticipate using uncemented implants should receive thorough training before embarking on an implantation.     

Greater trochanteric blood flow during total hip arthroplasty using a posterior approach.

The authors investigated the effect of a posterior surgical approach on the local femoral blood supply during primary total hip arthroplasty. Greater trochanteric blood flow measurements were made with a laser Doppler flowmeter at intervals during the performance of eight uncemented and nine cemented total hip arthroplasties. Complete detachment of the quadratus femoris was associated with a significant decrease in trochanteric blood flow in the uncemented and cemented groups. The lowest perfusion levels during the procedure were seen transiently with posterior dislocation of the femoral head, after which trochanteric perfusion was decreased by 66% in the uncemented group, and 61% in the cemented group compared with baseline values. Blood flow remained approximately half of baseline values after insertion of the femoral prosthesis in the uncemented and cemented groups. These changes in greater trochanteric blood flow may serve as a marker for reduction in proximal femoral blood flow during total hip arthroplasty, and subsequently relate to the extent of bony ingrowth, periprosthetic bone loss, and ultimately the incidence of implant failure caused by aseptic loosening.     

Clinical and Radiographic Evaluation of a Monoblock Tibial Component

Modular tibial components are the clinical standard in total knee arthroplasty despite the lack of evidence of improved function and longevity when compared with monoblock implants. This study describes the minimum 5-year outcomes for 125 total knee arthroplasties performed with monoblock tibial components in 101 patients. No patients were lost to follow-up. Average Knee Society Score was 87.1 at a mean follow-up of 5.2 years. Clinical and radiographic follow-up showed all components to be stable, no implants at risk of loosening, no observable osteolysis, and no observed change in bone density. Survivorship free of revision for tibial component loosening was 100% at 5 years. These results show excellent midterm durability of a partially cemented porous tantalum monoblock implant with uncemented pegs.     

Lymphocyte response to polymethylmethacrylate in loose total hip prostheses.

We investigated the lymphocyte-mediated immune response to polymethylmethacrylate bone cement in 26 patients who had revision surgery for aseptic loosening of cemented total hip arthroplasties, at a mean time of seven years after the first replacement. We studied eight patients with cemented total hip arthroplasties which were not loose as controls. Patch tests to polymethylmethacrylate bone cement were positive in 13 patients with loosening, and these patients had higher lymphoblast transformation values against polymethylmethacrylate bone cement patients with a negative skin reaction (p < 0.01) or those in the control group (p < 0.001). Specific monoclonal antibodies were used to assess the percentage of certain cells of the immune system according to their cluster of differentiation (CD). There was a higher number of total T and B lymphocytes (CD2 and CD22) and interleukin-2 receptor-positive lymphocytes (activated cells, CD25) in patients with loose prostheses. More CD25 lymphocytes were found in patients with positive patch tests. The activation of the lymphocyte-mediated immune response was not related to the presence or absence of aggressive granulomatous lesions at the cement-bone interface.     

The bipolar prosthesis in avascular necrosis of the femoral head.

Data are presented from five studies assessing the results of hip joint replacements with bipolar prostheses or total hip arthroplasties. Long-term results of 23 cemented bipolar prostheses were comparable with 14 uncemented bipolar prostheses. Excellent or good results were obtained about 60% of the time. Groin pain was objectionable in at least 12% of the patients. In a study of 43 arthroplasties performed between 1971 and 1982 in 51 patients with systemic lupus erythematosus and avascular necrosis of the femoral head, 29 cemented total hip arthroplasties were compared with 14 bipolar prostheses. Excellent or good results were obtained in 90% of the total hip arthroplasties and only 50% of the bipolar prostheses. A study of the complications and reoperations of both cemented and uncemented bipolar and total hip replacements performed between 1982 and 1986 showed a higher incidence of both complications and reoperations with the bipolar prosthesis. Clearly, the results of bipolar prostheses in avascular necrosis are inferior to those of total hip replacement.     

A qualitative and quantitative study of retrieved femoral heads in three different types of resurface hip arthroplasties

Tissue reactions and percentage of mineralized bone in three different types of retrieved femoral head hip resurface prostheses were studied in undecalcified ground sections without removing the metal. All of the prostheses demonstrated soft tissue between the cement-implant and bone. There were some areas without soft tissue between bone and cement. This bone was often not normally stained, indicating a disturbed mineralization. The soft tissue layer in the cemented prostheses was observed in different stages of necrosis, while the uncemented prostheses demonstrated a thick collagen membrane. One of the cemented groups demonstrated a gradual decrease of mineralized bone towards the cement. The uncemented implants revealed normal bone qualitatively and quantitatively when the bone bordering the prosthesis was excluded. Too high interfacial stresses were probably a major failure mechanism, especially in the rapidly failed noncemented prostheses. Negative long-term effects of the cement on the bone may have contributed to failure in the cemented resurface arthroplasties.     

Localized osteolysis in stable, non-septic total hip replacement

We are reporting four cases of extensive, localized bone resorption adjacent to a rigidly anchored, cemented total hip replacement. None of these hips showed evidence of infection on clinical, bacteriological, or pathological evaluation. The tissue from the regions of osteolysis showed sheets of macrophages and foreign-body giant cells invading the femoral cortices. Abundant methylmethacrylate particulate debris was present in the tissues, but polyethylene wear debris was absent. The histological appearance of this tissue resembled that reported about loosened total hip implants with the exception of the synovial-like layer at the cement surface. The cases reported here show that aggressive bone lysis may occur around stable cemented total hip arthroplasties without the presence of sepsis or malignant disease.     

Conversion of failed hip hemiarthroplasties after femoral neck fractures

Hemiarthroplasty has been the preferred treatment for fractures of the femoral neck in elderly patients. The objective of the current study was to assess the outcome of revision of failed hemiarthroplasty to total hip arthroplasty in patients with a primary diagnosis of a femoral neck fracture. One hundred thirty-two conversions were done in 108 women and 24 men. One hundred two cemented and 30 uncemented hemiprostheses were revised to 88 cemented, 17 uncemented, and 27 hybrid total hip arthroplasties and the patients were followed up an average of 7.1 years (range, 5.1-15.3 years). Nine hips (6.8%) were revised for loosening and four additional hips (3%) were loose at the last followup. Survivorship free of revision was 96.5% (95% confidence interval, 93%-100%) at 5 years and 92% (95% confidence interval, 86%-98%) at 10 years. Major perioperative complications occurred frequently (45%), including 12 intraoperative femoral fractures (9%) and 13 dislocations (9.8%) Three of 12 (25%) of the intraoperative femoral fractures developed later femoral component loosening and all occurred during conversion of an uncemented Austin-Moore type hemiprosthesis. Conversion of endoprostheses to total hip arthroplasties after femoral neck fractures is fraught with high complication and loosening rates. Careful patient selection for each type of arthroplasty (hemiarthroplasty versus total hip arthroplasty) may help ameliorate the outcome of arthroplasty for patients with femoral neck fractures.     

Human monocyte response to particulate biomaterials generated in vivo and in vitro

We studied the ability of four clinically relevant particle species to stimulate human peripheral blood monocytes to release bone-resorbing agents, including interleukin-1 (both interleukin-1α and interleukin-1β), interleukin-6, and prostaglandin E₂. The species studied were titanium-6%aluminum-4%vanadium (TiAlV), commercially pure titanium, fabricated ultrahigh molecular weight polyethylene, and polyethylene retrieved from interfacial membranes of failed uncemented total hip arthroplasties. For all species, the mean size was less than 1 μm. Human peripheral blood monocytes were challenged with these particles in a uniform manner on the basis of surface area. Phorbol 12-myristate acetate, zymosan, and nonphagocytosable titanium particles served as controls. Stimulation of human monocytes is a function of the composition and concentration of particles. In this study. TiAlV particles appeared to be the most competent to elicit the synthesis and release of inflammatory mediators. Particles of commercially pure titanium and of fabricated ultrahigh molecular weight polyethylene also could induce the release of various cellular mediators, albeit at a lower level, whereas the particles of polyethylene retrieved from interfacial membranes were less stimulatory in these short-term in vitro experiments.     

Low contact stress mobile bearing total knee arthroplasty: Results at 5 to 13 years

A total of 139 mobile bearing knee arthroplasties in 104 patients were evaluated at a mean follow-up of 7.8 years (range, 5-13 years). There were 80 cemented knees, 50 uncemented, and 9 hybrid (cemented tibia, uncemented femur). Ten knees were revised. Four knees were revised for aseptic loosening of an uncemented tibial component, and 1 knee was revised for loosening of an uncemented femoral component. One knee was revised for a recurrent dislocating bearing, and 1 knee was revised for instability. No mechanical loosening occurred in the cemented components. Three knee arthroplasties were revised for infection. A total of 66 patients (92 knees) were evaluated clinically and radiographically. Radiographic evaluation showed a 27% incidence of radiolucent lines for the femur and a 31% incidence of radiolucent lines for the tibia. No components were considered radiographically loose. The survivorship of mobile bearing knee arthroplasties was 93% at an average follow-up of 7.8 years. Aseptic loosening was statistically higher in uncemented components (P=.0051).     

Midterm results in 500 titanium alloy straight femoral stem prostheses -cemented and cementless technique

Summary Mid- and long term stability is still the major challenge in total hip replacement (THR). A consecutive series of cemented 250 cases and of uncemented 250 cases was analyzed in a prospective follow-up study. The femoral component of the BiCONTACT hip stem system with the same design for cemented and uncemented implantation was used. While the cemented stems had a smooth surface, the cementless implants were proximally coated with a microporous titanium plasmaspray (Plasmapore^®). Follow-up time averaged 7 years for cemented and 6.5 years for uncemented THRs. Follow-up rate was 88.7% in cases treated with cemented stems and 93.1% in cases treated with an uncemented stem. The rate of aseptic loosening was 1.2% for the cemented version and 0.4% for the uncemented one. Radiological loosening could be observed in another 1.2% of the cemented stems but was not found in the uncemented cases. Our data suggest excellent midterm stability of both the cemented and the uncemented version of the BiCONTACT hip stem system. Early aseptic loosening especially of the cemented titanium alloy straight stem has not occurred in our series as reported recently. The prosthesis design and follow-up time may therefore play an important role. The long-term results for both cemented and uncemented BiCONTACT prostheses of our series are still to be evaluated.     

全髋置换后股骨部分骨溶解现象分析

从1986年～1993年,对37个病人的44个髋关节实施丁全髋置换手术,其中14个病人的15个髋关节进行了临床随访,平均随访时间为7年。又从这个时期年实施的156个人工股骨头置换的病人中,随机抽出16个骨水泥的人工股骨头置换作为对照组。两组病人,虽然使用相同的第一代骨水泥技术,相同金属材料的假体。但全髋置换组的骨溶解带数为90个,而人工头组的骨溶解带数为6个(p<0.01)。结论是:造成骨溶解带数明显不同的原因,是由于全髋置换组中聚乙烯的杯所产生的聚乙烯颗粒造成的。     

Does cement increase the risk of infection in primary total hip arthroplasty? Revision rates in 56,275 cemented and uncemented primary THAs followed for 0-16 years in the Norwegian Arthroplasty Register

Introduction The cementation of a total hip prosthesis may cause bone necrosis, either by direct toxicity or by generation of heat during the polymerization process. This necrotic bone may create conditions that encourage the growth of bacteria. We compared the revision rates due to infection in primary uncemented total hip arthroplasties (THAs) with those of cemented THAs with antibiotic-loaded cement and to those of cemented THAs without antibiotic cement.

Methods Data from the Norwegian Arthroplasty Register for the period 1987-2003 were used. To have comparable groups, we analyzed only primary THAs performed because of primary osteoarthrosis, and where both the acetabular and the femoral component of the prosthesis were either uncemented or cemented (n = 56,275).

Results In total, 252 revisions due to infection were reported. Compared to the uncemented THAs (n = 5,259), the risk of revision due to infection for THAs without antibiotic cement (n = 15,802) was increased 1.8 times (CI 1.0-3.1; p = 0.04). No differences could be detected when compared to THAs with antibiotic-loaded cement (n = 35,214) (RR 1.2, CI 0.7-2.0; p = 0.5). The average operating time for uncemented THAs was 15 min less than for cemented THAs.

Interpretation The risk of revision due to infection was the same for uncemented and for cemented arthroplasties with antibiotic-loaded cement, but higher for cemented arthroplasties without antibiotic cement. Our findings can be explained by reduced resistance to infection caused by the cement, which appears to be neutralized by adding antibiotic to the cement.     

Revision of the uncemented hip prosthesis

In a series of 213 consecutive total hip replacements a.m. Lubinus, the clinical course after 72 revisions and 141 primary procedures was compared after 5 years. The revised THRs were uncemented Ring prostheses. Dislocation and peroperative fracture were more common in the revision group. Two failures because of aseptic loosening occurred in the revision group and 3 in the control group. No excisional arthroplasty was required, and no infections occurred. Radiographic evaluation of prosthetic positioning, component loosening, calcar resorption, and paraarticular ossification disclosed only slightly inferior results in the revision group. Clinically, the revised cases were not inferior to the primary ones. Revision of the uncemented hip seems less difficult than of the cemented hip.     

Revision of the uncemented hip prosthesis

In a series of 213 consecutive total hip replacements a.m. Lubinus, the clinical course after 72 revisions and 141 primary procedures was compared after 5 years. The revised THRs were uncemented Ring prostheses. Dislocation and peroperative fracture were more common in the revision group. Two failures because of aseptic loosening occurred in the revision group and 3 in the control group. No excisional arthroplasty was required, and no infections occurred. Radiographic evaluation of prosthetic positioning, component loosening, calcar resorption, and paraarticular ossification disclosed only slightly inferior results in the revision group. Clinically, the revised cases were not inferior to the primary ones. Revision of the uncemented hip seems less difficult than of the cemented hip.     

Role of inflammatory mediators and adhesion molecules in the pathogenesis of aseptic loosening in total hip arthroplasties

Concentrations of prostaglandin E₂, interleukin-6, and interleukin-8 were determined in the hip joint synovial fluid of 20 patients undergoing primary (n = 12) and revision (n = 8) total hip arthroplasties. Levels of soluble adhesion molecules were also investigated in these patients. There was a significant and marked increase in levels of prostaglandin E₂ (P < .001), interleukin-6 (P < .011), interleukin-8 (P < .0002), soluble intercellular adhesion molecule 1 (P < .07), soluble vascular adhesion molecule 1 (P < .0006), and soluble endothelial leukocyte adhesion molecule 1 (P < .0003) in joint fluid of patients undergoing revision. On the basis of these observations, it is suggested that synovial fluid and its inflammatory contents could play a significant role in the pathogenesis of aseptic loosening in total hip arthroplasties.