Cementless Total Hip Replacement Research Articles

Deep vein thrombosis screening after TKR venography vs Dopplers

This was combined with accurate costing data. At the time of this study, hospitals knew what they charged for total hip replacement but had very little information on costing. Two graduate students accurately costed both cemented and cementless total hip replacements at our institution and found that we could do each for approximately $10000 Canadian including all hospital and physician charges. This data was then combined with the time trade-off data to produce cost to quality adjusted life year data. We also collected the hip related cost to society of the patient and third parties for years one and two post-operatively, utilizing a detailed diary system. At two years post-operatively, the cost to QALY ratio was approximately $8200. We then compared this cost to QALY outcome data with other common medical surgical interventions. Laupacis et al. have developed a cost to QALY gradient to determine the cost effectiveness of various medical interventions. These interventions which are under $20000 are considered so cost effective that this intervention should be questioned. Interventions costing between $20001 and $100000 are moderately cost effective and probably should be funded. Those interventions over $100001 might be efficacious but are extremely expensive. Their adoption into clinical practice requires considerable discussion and analysis. Based on this assessment, it is obvious that total hip replacement represents one of the most cost effective medical and surgical interventions known.

Micromotion at the Bone-Stem Interface during the Gait Cycle after Cementless Total Hip Replacement: Influence of Stem Design and Loading Level

The micromotion distribution of a cementless stem relative to femoral bone and the stress transfer were calculated with a three dimensional model including bone non-homogeneity, anisotropy and discontinuity of the bone-implant interface. Two implant designs (anatomical, straight) were investigated to point out the geometry effects. Micromotion distributions were calculated over the entire interface during a complete gait cycle taking into account the hip musculature forces. Different loading levels (from 20% to 100% of total load) were stimulated. For the two implants, peak values of distractive and shear micromotions were maximal at the Single Limb Stance phase. The implant geometry had no sensible effects on distractive micromotion magnitude. Conversely, the implant design had noticeable influences on shear micromotions. Regarding the effects of loading levels, at 20% of the full load, interface shear micromotions were lower than 30μm over the entire interface allowing bony ingrowth and expected to ensure initial stability for both implants. At 40%, shear micromotions exceeding 30μm appeared and were located differently according to the stem design.

Cementless total hip replacement does not change bone mineral density of the lumbar spine, DEXA measurements in 50 patients.

We measured the lumbar spine mineral density with the dual-energy x-ray absorptiometry method, 8 days, 3 and 6 months after total hip replacement in 50 patients and found no statistical differences over time.

Unpredictable progression of osteolysis following cementless hip arthroplasty. 24 femoral components followed for 6-10 years.

We reviewed 24 hips that developed femoral osteolytic lesions following cementless total hip replacement with a Porous-Coated Anatomic prosthesis after a mean of 8 (6-10) years. 15 of the hips showed hardly any radiographic deterioration in the osteolysis. 2 became much worse with dramatic loss of bone stock. Both of these hips required revision of the acetabular component as well as bone grafting of the otherwise well-fixed femoral component. The remaining 7 hips showed mild-to-moderate enlargement of the lesions. All 24 hips were asymptomatic. Blood tests and bone scintigraphy were of no predictive value in assessing the probable progression of the lesions. Serial radiography remains the cornerstone of the monitoring of osteolysis, following cementless hip replacement, the extent of bone loss being usually far greater than indicated by radiographic examination.

An integrated system for cementless hip replacement

Describes robotics and medical imaging technology in the enhancement of precision surgery. The authors consider: cementless total hip replacement application; system overview; ORTHODOC preoperative planning workstation; ROBODOC surgical assistant; safety features; surgical protocol. >

ASSESSMENT OF THE SYMPTOMATIC TOTAL HIP

This new information has recently been incorporated into a series of algorithms for evaluating painful cemented and cementless total hip replacements. As the interpretation of many tests varies significantly between cemented and cementless components, the approach to these two situations differs accordingly. Careful review of sequential plain radiographs remains a mainstay of initial evaluation. The sedimentation rate is also a cost effective method of adding useful information. Based on this assessment, cemented and cementless components can be classified as loose, well fixed, or having lysis without being loose. Subsequent evaluation should incorporate new information regarding the effectiveness, limitations, and cost of various diagnostic tests available for the evaluation of the painful total hip replacement.

An image-directed robotic system for precise orthopaedic surgery

The authors have developed an image-directed robotic system to augment the performance of human surgeons in precise bone machining procedures in orthopaedic surgery, initially targeted at cementless total hip replacement surgery. The total system consists of an interactive CT-based presurgical planning component and a surgical system consisting of a robot, redundant motion monitoring, and man-machine interface components. In vitro experiments conducted with this system have demonstrated an order-of-magnitude improvement in implant fit and placement accuracy, compared to standard manual preparation techniques. The first generation system described in this paper was used in a successful veterinary clinical trial on 26 dogs needing hip replacement surgery. It was the basis for subsequent development of a second-generation system that is now in human clinical trials.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The influence of prosthesis design on stress shielding in cementless total hip replacement

The influence of prosthesis design on stress shielding in cementless total hip replacement

Ingrowth Surfaces

Plasma spray coatings on titanium alloy total hip replacements (THRs) provide a viable alternative to sintered bead or diffusion-bonded fiber metal ingrowth surfaces. The plasma spray process enables the titanium alloy implant to retain 90% of its fatigue strength, as opposed to less than 50% for sintered or diffusion-bonded cementless devices. Laboratory and clinical evidence suggest that plasma spray cementless THRs perform as well, if not better, than other cementless implants. Clinical trials have demonstrated the superiority of a plasma spray cementless THR (Mallory-Head) over a sintered bead cementless THR (PCA) and the equivalent results to a cemented THR. Plasma spray coatings on titanium alloy hip replacements provide a safe, predictable coating for cementless fixation of THRs in the short to medium range of follow-up periods.

ハイドロキシアパタイトコーティングＴＨＲの検討

We investigated hydroxyapatite (HA)-coated metal implants to improve the fixation of cementless total hip replacements (THR). We found postoperative thigh pain in 30.7% (46/150 joints) of Harris Galante Porous (HGP) type THR and 5% (1/20 joints) of HA-coated THR. HA-coatedtitanium sprayed Ti-6Al-4V might improve the fixation of HA-coated THR in which HA was coated onto the flat Ti-6Al-4V.

Biocompatibility of Polyethylene and Host Response to Loosening of Cementless Total Hip Replacement

A human lymphocyte culture protocol was used to identify the biocompatibility pattern of fine particulate ultra-high molecular weight polyethylene. Polyethylene did not cause an increase in lymphocyte DNA synthesis as assessed by the 3H-thymidine incorporation method on culture Days 1, 3, nor 5. As analyzed with monoclonal activation markers, the polyethylene dependent expression of major histocompatibility complex (MHC) class II antigen as well as interleukin-2 receptor (CD25) was virtually nonexistent. An apparent increase in the amount of CD11b positive monocytes/macrophages from 7% +/- 2% to 22% +/- 6% was recorded. Samples of pseudocapsules of the totally replaced hips (THR) obtained at revision operations for aseptic loosening of cementless prostheses with polyethylene lining of the acetabular component, were obtained from ten patients for immunopathologic studies. In seven cases the prostheses consisted of chromium-cobalt-molybdenum steel alloy and in three cases of titanium. Revisions were performed on average 4.6 years (range, 2.5-7) after insertion of the prostheses. The predominant cell in the lining cell layer of the periprosthetic cavity was in each case the CD11b, CD68, and nonspecific esterase positive but endogenous peroxidase-negative macrophage. Proline 4-hydroxylase positive fibroblasts dominated the stroma that was also inhabited by usually perivascular mononuclear cell infiltrations of mainly CD11b/CD68 phenotype with occasional CD4-positive cells. Only few mononuclear cells were activated CD25 positive T cells or CD19-positive B-lymphocytes. In titanium-based THRs, the cytoplasm of the macrophages contained a large number of small metallic particles, although this phenomenon was not seen in chromium-cobalt-molybdenum steel-based THRs. Fine particulate ultra-high molecular weight polyethylene is immunologically relatively insert. Nevertheless, it causes a clear foreign body type of phenomenon in vitro. The loosening of cementless acetabular components was associated with CD11b- and CD68-positive macrophage reaction in the pseudocapsular tissue. In any case, there is no clinical or experimental evidence to suggest that the use of cementless THR prostheses with polyethylene sockets would prevent an adverse biologic host response.

Development of a surgical robot for cementless total hip replacement

The combination of robotics and medical imaging may soon provide orthopaedic surgeons with a tool that significantly increases the precision of cementless total hip replacement operations and directly links preoperative planning with surgical execution. Twenty-six successful robot-assisted operations have been performed on dogs and the first clinical trials on human patients have recently taken place.

The Rationale for Cementless Total Hip Replacement

Current cementing techniques of distal plugging, pulsatile water cleaning of the canal, and retrograde filling with PMMA in a low-viscous state prepared using porosity reduction techniques and then pressurized have been shown to give excellent results at 10 or more years after operation. However, physical and aging characteristics of PMMA do not guarantee that those results will hold up in the 20- to 30-year time frame. Fifteen-year experience with bony ingrowth systems indicate the development of a durable interface without PMMA, although the interface does appear more vulnerable to attack by the biologic reaction to HMWPE debris. Bone remodeling appears more favorable around proximally fixed bone ingrowth prostheses than around distally fixed prostheses. Softening of the physical characteristics of the stem tip may reduce the incidence of thigh pain. Patients with high activity potential and a life expectancy of greater than 25 years should be strongly considered for a proximally fixed bone ingrowth or ongrowth prosthesis.

Stem curvature and load angle influence the initial relative bone‐implant motion of cementless femoral stems

A 6 df measurement system was used to investigate the initial relative bone-implant motion of two types of cementless total hip replacement femoral components-a straight stem and a curved stem. Five pairs of fresh frozen femurs from human cadavers were tested with loads applied to the femoral head at angles characteristic of level walking, stair-climbing, and rising from a chair. The most important findings were that (a) the resultant proximal translations were twice as high with the straight stem as with the curved stem at load angles encountered in stair-climbing and rising from a chair, (b) both stem types had more motion at load angles encountered in stair-climbing and rising from a chair than in level walking, with the increases ranging from 3 to 14-fold, (c) there was as much as 66-fold more motion distally than proximally, and (d) the amount of interface motion varied by 5-fold between the medial and lateral surfaces of the distal part of the implant because of the combined effects of translation and rotation. The amount of initial bone-implant motion of the femoral component was found to be particularly sensitive to off-axis loading; this suggests that stair-climbing and rising from a chair should be avoided in the early postoperative period when a cementless porous-coated femoral stem has been used.

Sequential haematogenous infection of bilateral cementless total hip replacements

We report a patient with bilateral uncemented total hip replacements in whom a deep infection on the second side may have been caused by a transient bacteraemia associated with a revision operation for deep infection on the first side. Both hips were successfully treated by one-stage exchange.

Cementless bipolar hemiarthroplasty and cementless total hip replacement arthroplasty in avascular necrosis of the femoral head

Cementless bipolar hemiarthroplasty and cementless total hip replacement arthroplasty in avascular necrosis of the femoral head

Bone remodeling as a function of stem stiffness in cementless total hip replacement

Bone remodeling as a function of stem stiffness in cementless total hip replacement

Lateral or Valgus Shift: A Mode of Failure of Cementless Stems

Two cases of unusual valgus and lateral stem displacement in cementless total hip replacement are reported. A certain number of mechanical conditions must have been present to cause this unusual prosthesis displacement. The Authors suggest that the stem's design was one of these factors.

The progression of femoral cortical osteolysis in association with total hip arthroplasty without cement.

Twenty hips in twenty patients had development of femoral endosteal cortical erosion after a cementless total hip replacement with the Harris-Galante porous-coated implant. Serial anteroposterior and lateral radiographs of all of the affected femora were reviewed to determine the interval between the operation and the first recognition of the osteolytic lesion or lesions, as well as to evaluate the radiographic appearance and progression of the lesions. The twenty affected hips were followed for an average of fifty-three months (range, twenty to seventy-seven months) after the operation. Osteolysis was first noted radiographically at twelve to sixty-six months (mean, thirty-nine months) postoperatively; in most patients, it occurred around the distal portion of the prosthetic stem. Twelve (60 per cent) of the femoral components were shown to be loose, as proved either radiographically or operatively. Three of these components had been judged radiographically to be stable when the endosteal erosion had first been identified, but they had subsequently migrated. The remaining eight hips had no evidence of loosening. The osteolysis was more severe in the femora in which the component was loose than in those in which it was stable. Of the fourteen patients who were followed, twelve (86 per cent) had an increase in the size of the osteolytic lesions with time, and only one patient had some radiographic evidence of healing.

Cementless prosthesis of the hip joint with "spongy metal" surface. A prospective study.

Our investigations in human specimens and animal experiments show that prostheses with a spongy metal surface can become fixed by bony ingrowth to varying degrees. After consistent clinical and radiological follow-up over 12-65 months (mean 34 months) in a prospective study of 100 consecutive patients in whom 106 cementless total hip replacements had been carried out, we were able to show that after 1 year 82% of patients were pain-free with the prosthesis fixed by bony ingrowth, 8% were pain-free with the prosthesis fixed by dense fibrous tissue and 10% were not pain-free, but did not want revision surgery. Thigh pain decreased steadily from 53% 3 months postoperatively to 6.6% 15 months after operation. We believe that, when the implantation technique is exact, a high percentage of cementless spongy metal prostheses are fixed by bony ingrowth, and that a cementless prosthesis should be implanted only in patients under 60 years of age without osteoporosis.