Cement mantle defects in total hip arthroplasty: influence of stem size and cementing technique

The cause of isolated osteolysis in the femoral shaft around stem implants in patients with cemented THR has so far not been established. A number of factors have been considered such as torsional stability of the femoral stem implant, the time of reduction intraoperatively after cementing and iatrogenic and load-induced defects in the cement mantle. The aim of this in vitro investigation was to determine if the cementing technique or the thickness of the prosthesis stem, and thus its bending strength, influences the formation, extent and localisation of cement mantle defects. In vitro biomechanical loading tests were performed on twelve anatomically shaped femoral stem prostheses of two different thicknesses which were implanted in artificial bone. Six of the implants were fixed by conventional cementing technique, the other six by means of the vacuum technique. Compared with thicker implant stems, the slimmer stems fixed with the conventional cementing technique had a higher number of cracks in the cement mantle. Pore formation was localised predominantly in the interface area between the bone cement and the “cancellous” bone or “cortex” of the artificial bone. This was observed especially in the non-vacuum mixed cement, regardless of stem thickness. Large pores were found mainly in the cement around the thicker stems which had been mixed by the conventional method. The thickness of the stems, whether fixed with vacuum-mixed or non-vacuum mixed cement, had no significant influence on the percentage of pore area in the cement. In the nonvacuum mixed cement, there was no significant difference between the percentages of pore area in the proximal and distal parts of the shafts, whereas in the vacuum mixed cement the percentage of pore area was significantly larger in the distal than in the proximal part of the shafts. In the specimens of both stem sizes, the percentage of pore area in the vacuum mixed cement was significantly smaller than in the nonvacuum mixed cement. This explains the greater fatigue strength of vacuum mixed cement. The cyclic loading on the thicker stem prostheses, especially in those fixed with vacuum mixed cement, resulted in fracture between the prosthesis tip and the clamping device due to the local stiffness of the artificial bone. Due to this unfavourable biomechanical property of the artificial bone, further studies will be carried out on human femurs. Nevertheless, in view of the results presented here, the vacuum mixing technique has to recommended as the “state of the art” method in cemented total hip arthroplasty.     

Osteolysis in cemented versus cementless acetabular components

A prospective, randomized, double-blind, clinical trial comparing cemented with cementless total hip arthroplasty was performed to compare the prevalence and pattern of acetabular osteolysis. Both groups were similar before surgery. Acetabular components were metal-backed, titanium implants. Twenty-eight-millimeter modular femoral heads with titanium femoral stems were used. At a minimum 2-year and mean 4-year follow-up period (range, 2–6 years), 224 patients had clinical and radiographic data available. There was no significant difference in the prevalence of acetabular osteolysis between cemented (5%) and cementless (9%) fixation. With or without cement, the use of a titanium femoral head led to osteolysis within a relatively short period after surgery in almost all of the cases, although this was not significant. The pattern of acetabular osteolysis was different. Progressive osteolysis occurred predominantly in acetabular zone 1 in the cemented group and zone 2 in the cementless group. Cementless fixation of acetabular components has been advocated in an attempt to minimize osteolysis that may occur in cemented total hip arthroplasty. This study found no difference in the prevalence of acetabular osteolysis between the two groups.     

Hip arthroplasty with a collared straight cobalt-chrome femoral stem using second-generation cementing technique: a 10-year-average follow-up study

Clinical and radiographic results of 116 patients who had undergone 132 hip arthroplasties at our institution from 1983 to 1988 with a collared cemented straight cobalt-chrome femoral stem using second-generation cementing technique were reviewed. Twenty hips in 20 patients who were part of the original cohort were lost to follow-up. Mean age at the time of surgery was 68.2 years. Mean radiographic follow-up was 9.6 years with a minimum follow-up of 5 years. Ten-year survivorship of the component was 96.5% with revision considered as an endpoint and 94.2% with either revision or radiographic loosening considered the endpoint. Three implants (2.3%) were revised for aseptic loosening at a mean of 8.1 years after implantation. One implant (0.8%) was revised for septic loosening at 10.5 years after surgery. Of the implants not revised, 1 showed evidence of circumferential bone-cement radiolucencies, and 1 had radiolucencies at the implant-cement interface. Five of the surviving femoral components (5.0%) showed focal areas of cystic osteolysis, and proximal femoral bone resorption under the collar was seen in 32 patients (31.7%). There were no cases of cement fracture or stem subsidence. The biomechanical and material properties of this stem combined with second-generation cementing technique look promising for long-term survivorship.     

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.     

The results of revision knee arthroplasty with and without retention of secure cemented femoral components

We have compared the survival of 67 revision arthroplasties of the knee undertaken for aseptic loosening with and without the retention of a secure, cemented femoral component. All the patients had undergone a single primary procedure at a mean of nine years previously. In group I (25 knees) the original femoral component was secure and was retained. There were no abrasions or osteolysis. The knees were stable, normally aligned, with minimal bone loss. In group 1142 knees did not fulfil these criteria and underwent revision of both components. The mean follow-up was four years. Re-revision for loosening was required in seven knees (28%) in group I and three (7%) in group II (p < 0.01). The remaining knees function well with Knee Society scores averaging 84/69 and no radiological evidence of osteolysis. When revising cemented implants, retention of a secure femoral component cannot be recommended even when conditions appear to be suitable.     

Direct compression molded polyethylene for total hip and knee replacements.

Direct compression molded polyethylene is a process of creating a net-shaped component with finished articular surfaces from ultrahigh molecular weight polyethylene by applying heat and pressure to the raw resin (usually Hi-fax 1900) with the use of fixed geometry metallic tools. The final product has no machining or finishing. Sterilization was by gamma radiation in air. Between 1974 and 1978, there were 378 cemented T-28 stems (321 patients) and 171 cemented TR-28 stems (158 patients) articulating with a cemented direct compression molded acetabular component. Radiographically, linear wear was 0.06 mm per year for the T-28 stem and 0.05 mm for the TR-28 stems. The revision rates for the acetabulum were 9.5% and 7.9%, respectively with only two acetabula having osteolysis. On the femoral side, the revision rates were 11.1% and 12.8%, with 11 cases and one case of osteolysis, respectively. Between 1983 and 1996, 4583 AGC cemented total knee replacements were done with direct compression molded nonmodular tibial components. There was no osteolysis seen in these nonmodular compression molded total knee replacements even with 0.1% failure of the femoral components and 0.4% failure of the tibial components. Failure of all of the hip and knee implants was because of poor cement technique, instability, or both. Wear and osteolysis were minimal. Direct compression molded polyethylene has stood the test of time and is a good choice among the currently available polyethylenes.     

Analysis of 16 retrieved proximally cemented femoral stems

Sixteen proximally cemented, collared, and distally splined, Bridge Hip femoral stems with a matte proximal surface and smooth distal surface were retrieved because of loosening. Electron microscopy, with correlated elemental analysis, identified titanium particulate embedded in the internal surface of the cement mantle. Data supported the observations that loosening of the femoral stems was related to proximal debonding at the cement-implant interface, loosening at the proximal cement-bone interface, and inherent rotational instability. Cement-implant interface debonding resulted in the proximally matte femoral stem surface abrading with the opposing cement mantle, resulting in particulate and osteolysis in some cases. Careful consideration of implant design and clinically relevant biomechanical testing protocols should be considered before the clinical introduction of future proximally cemented femoral stems.     

Endosteal erosion in association with stable uncemented femoral components

Sixteen cases of patients who had focal femoral osteolysis after total hip replacement without cement were identified. Fourteen of them were included in a retrospective review of 474 consecutive total hip replacements without cement in 441 patients who had been followed for at least two years. The criteria for inclusion in the study were focal osteolysis with a femoral component that appeared stable radiographically, and no subsidence or change of position of the implant. All but two patients were men and were quite active. The average age was forty-seven years (range, twenty to sixty-five years). Fourteen of the sixteen patients had an excellent clinical result (a Harris hip score of 90 points or more). In two patients, the hip replacement was revised and, in a third, a biopsy was done. In all three patients, the implant was found to be firmly fixed to the femur. In the two hips that were revised, extensive ingrowth of bone was demonstrated histologically, there was no evidence of infection, and a well defined fibrous membrane was found around the smooth portion of the stem. The histological specimens from these two hips contained focal aggregates of macrophages with particulate polyethylene and metallic debris. In the biopsy material from the hip that was not revised, a fine fibrous membrane lined a cystic cavity. Although the membrane contained an occasional macrophage, no foreign material was identified. Trabecular microfracture and osteoclastic resorption of bone were seen next to the fibrous lining. With one exception, osteolysis was not identified less than two years postoperatively. In most patients, osteolysis appeared after three years. This study showed that femoral osteolysis can occur around uncemented components.     

Biomechanical and histologic investigation of cemented total hip arthroplasties. A study of autopsy-retrieved femurs after in vivo cycling

Eleven whole anatomic specimens of the femur were retrieved at autopsy from patients who previously had cemented total hip arthroplasty. Implant duration ranged from 0.5 to 210 months. Clinically and roentgenographically the implants were stable. A detailed biomechanical analysis evaluated bone strains and implant stability in both the single-limb stance and stair-climbing positions using a 100-pound spinal load. The stability offered by cement in these well-fixed prostheses was remarkable, with the maximum axial micromotion being 40 mu. This is a reflection of intimate osseointegration at the bone-cement interface with only rare intervening fibrous tissue. The strain gauge and photoelastic strain-coating studies revealed that marked stress shielding in the proximal medial femoral cortex persists long after a cemented femoral component is inserted. Even 17 years after surgery, the strain in the calcar region did not normalize.     

Contemporary total hip arthroplasty with and without cement in patients with osteonecrosis of the femoral head

BACKGROUND: The rate of failure of primary total hip arthroplasty in patients with osteonecrosis of the femoral head is higher than that in patients with osteoarthritis. The purpose of this prospective study was to document the clinical and radiographic results of arthroplasty with so-called third-generation cementing and the results of second-generation cementless total hip arthroplasty in ninety-eight consecutive patients with osteonecrosis of the femoral head. METHODS: Fifty patients who had had simultaneous bilateral total hip arthroplasty with a cemented stem in one hip and a cementless stem in the other and forty-eight patients who had had a unilateral total hip arthroplasty with a cementless stem were included in the study. A cementless acetabular component was used in all hips. The presumed cause of the osteonecrosis was ethanol abuse in fifty-seven patients, unknown in twenty-seven, fracture of the femoral neck in nine, and steroid use in five. There were eighty men and eighteen women. The mean age at the time of the arthroplasty was 47.3 years (range, twenty-six to fifty-eight years). Clinical and radiographic evaluations were performed preoperatively; at six weeks; at three, six, and twelve months; and yearly thereafter. The average duration of follow-up was 9.3 years. RESULTS: The average Harris hip scores in the group treated with unilateral arthroplasty (97 points) and the group treated with bilateral arthroplasty (94 points) were similar at the time of final follow-up. They were also similar between the group treated with cement (mean, 96 points) and that treated without cement (95 points). No component had aseptic loosening in either group. In one hip, a cemented femoral stem (2%) and a cementless cup were revised because of infection. Two cementless stems (2%) were revised because of fracture of the proximal part of the femur with loosening of the stem. Annual wear of the polyethylene liner averaged 0.22 mm in the group treated with cement (a zirconia head) and 0.14 mm in the group treated without cement (a cobalt-chromium head). The prevalence of osteolysis in zones 1 and 7 of the femur was 16% in the group treated with cement and 24% in the group treated without cement. CONCLUSIONS: Advancements in surgical technique and better designs have greatly improved the long-term survival of cemented and cementless implants in young patients with osteonecrosis of the femoral head. Although there was no aseptic loosening of the components, a high rate of linear wear of the polyethylene liner and a high rate of osteolysis in these high-risk young patients remain challenging problems.     

Bilaterale umschriebene Osteolyse nach zementierter Hüfttotalendoprothesenimplantation

The incidence of focal progressive osteolysis after THR is about 8% and 56%. Most often osteolysis is correlated with macrophage-induced osteoclastic bone resorption as a sequel of inflammatory reaction to wear particles. Recently these findings were published in respect to allergic reactions to implants, their alloying constituents, or bone cement. We report about a patient who developed bilateral localized osteolysis just below the cement mantle 5 years after cemented THR with a Müller straight stem. In the middle of the osteolysis small fragments of bone cement could be detected. Epicutaneous testing showed no reaction against cobalt, chromium, or nickel. Further epicutaneous testing in respect to ingredients of the bone cement were refused by the patient. Histological examination revealed a histiocytic reaction to wear particles and surrounding giant cells. To our knowledge, this is the first case of bilateral localized osteolysis after cemented total hip replacement. Taking all results of the current case into account, it is still unclear if a lymphocytic allergic contact reaction did contribute to the sequel of this case. Reports of immunologically induced incompatibility to components of bone cement, the development of extended testing procedures, and further scientific research should contribute to optimizing the care of patients.     

Stable partial debonding of the cement interfaces indicated by a finite element model of a total hip prosthesis

A simplified three-dimensional finite element model of the femoral component of a cemented total hip prosthesis was used to investigate whether partial debonding at the stem-cement or bone-cement interfaces propagates in a stable or unstable manner, and to assess the resultant variation of the stresses within the cement layer. The likelihood of unstable debonding under tensile failure mode was assessed both by a conventional monotonic strength criterion and by a fracture mechanics approach that took into account debonding due to fatigue loading. The model predicted that partial debonding at the cement interfaces would be stable and would not precipitate complete debonding. Among the various bonding conditions that were investigated, the maximum tensile stress within the cement layer was least with a small amount of debonding rather than with complete bonding. These results were consistent with clinical observations of nonprogressive or slowly progressive separation at cement interfaces in cemented femoral components that were otherwise well functioning and asymptomatic.     

Zement-in-Zement-Hüftrevision mit einem zementierten langen Prothesenstiel

Revision hip surgery often requires individualized techniques and implants. We report on a case of failed femoral revision in an extensively cemented femur with a concomitant proximal and dorsal femoral bone defect. We advocate the clinically effective revision procedure of antegrade drilling of the stable cement mantle and use of a cemented long-stemmed femoral component. This cement-in-cement revision technique is discussed along with the pertinent literature     

扩展型转子截骨技术在骨水泥型股骨柄翻修中的临床应用

目的探讨扩展型转子截骨技术在较困难的骨水泥型股骨柄翻修手术中的作用和临床效果。方法2002年2月至2006年5月采用扩展型转子截骨翻修股骨侧假体12例，应用扩展型转子截骨技术取出所有骨水泥和假体柄，重新植入翻修用假体柄，以多道金属线缆环扎固定。其中1例选择的是骨水泥股骨假体，11例是非骨水泥股骨假体。结果所有患者均获得随访，时间16～24个月，术后6个月所有截骨处均愈合，无大转子移位。Harris评分由术前平均（48．4±7．5）分上升至术后平均（89．3±8．1）分（为术后1年的评分），假体无松动、下沉、假体周围未见骨吸收、骨溶解。结论扩展型转子截骨对骨水泥取出困难的股骨侧翻修术具有骨水泥取除彻底，安全可靠，手术时间短，并发症少的优点。     

Fifteen-year survivorship of a collarless,cemented, normalized femoral stem in primary hybrid total hip arthroplasty with a modified third-generation cement technique

This prospective review aimed to evaluate 15-year survivorship of the collarless, third-generation cemented, normalized, Omnifit (Osteonics, Allendale, NJ) femoral stem in hybrid total hip arthroplasty (THA). Between January 1986 and June 1990, a single surgeon prospectively implanted 250 consecutive hybrid THAs (215 patients) using a modified third-generation cement technique in selected patients. A Harris-Galante (I or II) (Zimmer, Warsaw, IN) cementless shell with modular polyethylene (4150 resin) liners gamma-sterilized in air were implanted. Kaplan-Meier survivorship of the femoral or acetabular component with mechanical failure (revision for aseptic loosening) as the end-point was 100% ± 0% at 15 years. Wear couple exchange and bone grafting was performed in 1 case (0.4%) for progressive acetabular osteolysis. This report supports femoral component centralization and good cement mantle to ensure durability of the collarless, cemented, normalized femoral stem with a surface roughness of 30–40 microinches.     

Patterns of Cement Distribution in Total Hip Resurfacing Arthroplasty

In this in vitro study, 4 different resurfacing implants have been evaluated with a simulated femoral head: 2 types of cement have been used (low and high viscosity) and 2 different cementing techniques have been performed: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). High-viscosity cement shows a homogeneous distribution all over the femoral head. Low-viscosity cement shows a massive polar concentration with insufficient if not absent distribution in the equatorial zone. Polar cement concentration could be held as a risk factor for early implant failure. It could have 2 effects on femoral head: biologic (excessive local exothermic reaction could cause necrosis of the osteocytes) and biomechanical (it could lead to uneven load distribution on the femoral head).     

Use of a polyglycolide lactide cement plug restrictor in total hip arthroplasty.

The use of a polyglycolide lactide cement plug restrictor in cemented femoral fixation during total hip arthroplasty was evaluated. Femoral cement pressurization was evaluated in vitro in a cadaveric model and the host response to polymer degradation was evaluated in vivo in a canine total hip arthroplasty model. Sixteen embalmed anatomic specimen femurs were prepared for cement femoral fixation. The intramedullary canal was plugged with either an ultrahigh molecular weight polyethylene cement plug restrictor or a polyglycolide lactide cement plug restrictor. Peak pressures in the proximal, mid, and distal portions of the cement mantle were recorded during cement insertion, cement pressurization, and implant insertion. There was no difference between the two plug groups in peak pressures throughout the cement mantle during cement insertion, pressurization, or implant insertion. Total hip arthroplasty using a cementless acetabular component and a cemented femoral stem was performed in 24 dogs. The femoral intramedullary canal was plugged with a polyethylene or a biodegradable cement plug restrictor. The dogs were sacrificed at 7 weeks, 10 months, or 15 months. Radiographically, no osteolytic lesions were seen around either plug type. Histomorphometrically, the polyglycolide lactide plugs appeared intact at 7 weeks and partially degraded by 10 and 15 months. In both plug groups, a mild fibrohistiocytic reaction with infiltration of fibrocytes, histocytes, and endothelial cells was seen. No osteolysis was observed. The results of the current study show that femoral cement pressurization can be attained in vitro using a biodegradable cement plug restrictor and that for as long as 15 months in the in vivo canine model there were no adverse reactions associated with use of these plugs compared with conventional ultrahigh molecular weight polyethylene plugs.     

Long-term results of cemented Charnley low-friction arthroplasty in patients aged less than 30 years

The results of cemented Charnley low-friction arthroplasty in patients aged less than 30 years are presented. Eighty-three arthroplasties were performed on 55 patients with an average age of 24.9 years (range, 17–29 years) and an average follow-up period of 240 months (20 years; range, 62–360 months). There were 2 nonfatal pulmonary emboli, 2 cases of deep sepsis, and 3 fractured femoral implants. Twenty-eight acetabular components migrated (34%), 25 have been revised (30%), and the average annual acetabular wear rate was 0.12 mm. Sixteen femoral implants subsided (19%), and fracture of the tip of the cement mantle occurred in 8 hips (10%). Nineteen femoral components (23%) were revised; femoral osteolysis was seen in 15 hips (18%) and changes in the calcar in 33 (38%). Acetabular component survivorship was 92% (95% confidence interval, 85–98%) at 10 years, 70% (60–81%) at 20 years, and 68% (57–79%) at 25 years, with the figures for the femoral implant being 93% (87–98%), 76% (66–86%), and 73% (62–85%), respectively.     

Radiographic analysis of a low-modulus titanium-alloy femoral total hip component. Two to six-year follow-up

We performed a detailed serial radiographic analysis of the femoral component of 323 cemented low-modulus titanium-alloy total hip prostheses. There was a low incidence of femoral component loosening as manifested by radiolucent zones at the stem-cement interface or cement fractures. There was also a low incidence of resorption of the calcar and cortical hypertrophy. Comparison of our data with those of others indicated that the incidence of loosening, calcar resorption, and cortical hypertrophy was usually lower than with similarly designed conventional high-modulus Charnley stems. These findings appear to support computer-modeling studies that have predicted a more even distribution of stresses along the entire length of the stem of the titanium-alloy prosthesis. Of the two configurations of femoral components used, the straight stems demonstrated a significantly lower incidence of radiographic evidence of loosening, calcar resorption, and cortical hypertrophy than the curved stems did. These findings have provided sufficient biomechanical rationale for the evolutionary development of the second-generation femoral components, which incorporate many features of the straight stem.     

Cemented total hip arthroplasty: still relevant in the new millennium?

Total hip arthroplasty can be performed successfully using cement or cementless technology. Cemented femoral stems can achieve enduring long-term suvivorship as long as meticulous surgical technique is utilized and patient selection is appropriate. Cemented acetabular components should only be utilized in patients with less than 10 years of remaining life expectancy. Critical risk factors for cemented total hip arthroplasty include atrophic osteoarthrtis on the acetabular side and unfavorable femoral geometry for the femoral stem such as "the stove-pipe" canal. Rapid polyethylene wear and osteolysis are rarely seen in contemporary cemented total hip arthroplasty performed with a smooth, tapered, collarless femoral stem with a highly polished head and a well-designed acetabular component.