A prospective study of 100 consecutive Harris-Galante porous total hip arthroplasties. 2-5-year results

A Role for Modern Primary Cementless Femoral Stems in Revision Hip Arthroplasty

BACKGROUND

In revision total hip arthroplasty (THA) cases with preserved femoral metaphyseal bone, tapered proximally porous-coated "primary" femoral stems may be an option. The objective of this study was to compare outcomes of patients with Paprosky I or II femoral bone loss undergoing revision THA with either a primary metaphyseal-engaging cementless stem or a revision diaphyseal-engaging stem.

METHODS

This was a retrospective analysis of 70 patients with Paprosky I or II femoral bone loss who underwent femoral revision. 35 patients who were revised using a primary cementless femoral stem were compared with 35 patients who underwent femoral revision using a revision diaphyseal-engaging stem. The groups were similar regarding age, gender, body mass index, and American Society of Anesthesiologists. Clinical and radiographic outcomes and complications were compared over an average follow-up of 2.9 years (SD 1.4).

RESULTS

Revision THA was most commonly performed for periprosthetic joint infection (N = 27, 38.6%). The groups were similar with regards to Paprosky femoral classification (P = .56), length of stay (P = .68), discharge disposition (P = .461), operative time (P = .20), and complications (P = .164). There were no significant differences between primary and revision femoral stem subsidence (0.12 vs. 0.75 mm, P = .18), leg length discrepancy (2.3 vs. 4.05 mm, P = .37), and Hip Disability and Osteoarthritis Outcome Score Jr (73.1 [SD 21.1] vs. 62.8 [SD 21.7], P = .088). No patient underwent additional revision surgery involving the femoral component.

CONCLUSION

Use of modern primary cementless femoral stems is a viable option for revision hip arthroplasty in the setting of preserved proximal femoral metaphyseal bone. Outcomes are not inferior to those of revision stems and offer potential benefits.

The 21- to 27-year results of the Harris-Galante cementless total hip arthroplasty

BACKGROUND

The Harris-Galante total hip arthroplasty (THA) is a first-generation cementless THA with a porous coating for biological fixation of the implant. Many studies report excellent long-term results for the acetabular cup, but few long-term studies exist for the femoral stem because of relatively poor short-term and midterm results. Here we present the 21- to 27-year results of the cup and the stem of the Harris-Galante THA.

METHODS

From 1985 to 1991, 102 Harris-Galante THAs were inserted in 82 patients. At the time of the THA, the mean patient age was 54 years (range, 20-78 years). The primary diagnosis was secondary osteoarthritis due to developmental hip dysplasia (69 [68%] hips). The Japanese Orthopaedic Association (JOA) hip score and thigh pain were measures of clinical outcome. Radiographic review was performed retrospectively. Implant survival was evaluated by Kaplan-Meier analysis.

RESULTS

Of 102 hips, 35 hips were from 31 deceased patients, 5 patients (6 hips) were lost to follow-up, 12 hips were revised, and 49 hips were from patients living at the latest follow-up. Among the living patients, 36 hips had a clinical evaluation and 42 hips had a radiograph obtained more than 21 years. The JOA hip score improved from 42 points preoperatively to 83.5 points at the latest follow-up. Thigh pain was reported in 13 hips. One cup and four stems were loose at the latest radiographic review. Most cup revisions were related to acetabular osteolysis. Fifteen hips showed severe stress shielding. Kaplan-Meier analysis of survivorship with any revision, acetabular reoperation, stem revision, and stem loosening as the end point was 87.0%, 90.3%, 95.7% and 86.4%, respectively, at 24.6 years.

CONCLUSIONS

Long-term implant survival and clinical results of the Harris-Galante THA were good. Acetabular osteolysis-related cup loosening was a problem of the cup. Loosening, thigh pain, and stress shielding were problems of the stem.

Initial stability of press-fit acetabular components under rotational forces

The primary goal of this study was to determine the initial press-fit stability in acetabular components without screw fixation. Mechanical testing was performed with the implantation of press-fit acetabular components in cadaveric specimens. No significant difference was found in load to failure testing between 1 and 2 mm of under-reaming. However, there was significant variability in bending forces required to create 150 μm of micromotion ranging from 49.3 N to 214.4 N. This study shows that cups implanted in a press-fit fashion, which are felt to be clinically stable, have high degrees of variability in resisting load and may be at risk for loosening. There is a need for more objective intra-operative techniques to test cup stability.

Subsidence in two uncemented femoral stems: An in vitro study

Many aspects of the performance of different implant designs remain as open questions in total hip arthroplasty. Despite the increased survivorship of each hip replacement, the amount of bone removed during surgery remains an important factor because of the potential need for revision surgery. Given that a smaller implant will have less surface area over which to transfer load, constructs that preserve more bone stock may be susceptible to mechanical complications related to the fixation of the implant in the femur. To assess mechanical fixation, this study compared the fiber metal taper and Mayo conservative hip stems in subsidence, frontal plane rotation and failure load. After dual-energy x-ray absorptiometry scans, pairs of cadaveric femurs received implants of each type and were loaded for 10,000 cycles. The subsidence and rotation were measured. Finally, specimens were loaded to failure. The subsidence and rotation after cyclic loading were −0.73 mm and 0.1°, respectively, for the Mayo implants and −0.87 and 0.52°, respectively, for the fiber metal taper implants, but no significant differences between implant types were found. There was also no significant relationship to bone mineral density. A power analysis revealed that 914 specimens would have been required to achieve a power of 0.8.

Migration and wear of the Duraloc "1200 series" cup associated with Enduron UHWMPE using the EBRA method and the Imagika software

We report a retrospective study on 122 THA using Duraloc "1200 series" cups. All patients received a 28-mm head (107 Al2O3, 15 CoCr). The mean age of the patients at surgery was 56.3 years and the mean follow-up was 137 months.Mean migration at two years using the EBRA method was 0.18 mm cranially and 0.16 mm medially. Mean polyethylene wear was 0.03 mm/year using the Imagika software and 0.06 mm/year using EBRA. Only one patient presented with abnormal polyethylene wear of 1.7 mm at 90 months with Imagika and 2.4 mm with EBRA. The Duraloc cup seems to be a reliable implant in respect of bone fixation and resistance to wear.

Seven to twelve year results with Versys ET cementless stem. A retrospective study of 225 cases

A retrospective review was conducted to evaluate the mid-term results (8.5 years follow-up) of the Versys ET stem (Zimmer, Warsaw, Indiana, USA). From 1995 to 2000, 225 total hip arthroplasties (THA) were performed using this device. All patients were evaluated clinically by the Harris Hip Score, and radiographically. The Hip Score increased from 54 preoperatively to 97 points postoperatively. The stem displayed a varus alignment between 5 degrees and 10 degrees in 17 cases without any clinical consequences (HHS 96.8). We recorded one case of septic loosening and one case of aseptic loosening. The stability of the stem was radiographically evaluated according to Engh's criteria, confirming bone ongrowth in all other cases.

Results of the cementless Plasmacup in revision total hip arthroplasty: a retrospective study of 72 cases with an average follow-up of eight years

BACKGROUND

There are multiple revision implant systems currently available for socket revision in revision total hip arthroplasty. Up until now, not all of these systems have been followed up with regards to their long-term use as a revision implantation.For the first time, this study presents the hemispherical porous-coated socket Plasmacup SC, produced by Aesculap, Tuttlingen, Germany, and the clinical and radiological mid-term results of this revision cup implant.

METHODS

Over a period of ten years the Plasmacup SC press-fit-cup was used as a revision implant in 72 consecutive aseptic cases which were included in this retrospective study. The mean follow-up period was 8 years. Bone graft transplantation was performed in 32% of all cases. In 90%, the cup was fixed with additional screws. The follow-up radiographs were analysed with regards to cup migration, osteointegration and osteolysis in the DeLee zones using a computer aided program taking the teardrop figure as a main point of reference. For clinical evaluation the Harris-Hip-Score and the WOMAC-Score were utilized.

RESULTS

At the follow up examination, the mean Harris-Hip-Score was 83.5 points and the mean WOMAC-Score 34.7 points. 93% of all patients were satisfied with the result of the operation. No aseptic cup loosening could be observed and only one cup had to be removed due to infection. No significant longitudinal or transversal cup migration could be observed.

CONCLUSION

Aesculap's Plasmacup SC is suitable as a cementless cup revision implant. There is stable cup osteointegration, post press-fit implantation, even in the case of major acetabular bone defects.

The rationale for total hip replacement in over 60-year-old patients

The total hip replacement (THR) survival potential is linked to the material, to surgical technique and to patient's characteristics. Cemented and cementless systems exist in a wide variety of shapes, sizes, configurations, materials and surface treatments. Aseptic loosening remain the principal mechanism of prosthetic failure and the choice of right matching for each prosthesis-patient is the main issue to obtain a very good long-term implant fixation. Cement fixation is always solidly achieved but it can break down under mechanical and biological pressure. Stability with cementless fixation must be created by the initial bone response to the implant. Clinical studies and long-term results with THR showed that in patients with age between 60 and 70 years, it is important to analyze several parameters (bone quality and morphology, life-limiting diseases and levels of activity) to make the appropriate selection of components and type of fixation.

Total hip arthroplasty with a collarless, tapered, fiber metal proximally coated femoral stem: minimum 5-year follow-up

The purpose of this study was to evaluate the midterm results, osteointegration potential, and implant-related complications of a cementless, collarless, proximally coated, distally tapered femoral hip prosthesis. The clinical and radiographic results for 129 hips in 116 patients after total hip arthroplasty with a Fiber Metal Taper (Zimmer, Inc ,Warsaw, Ind) femoral stem are reported. One hundred twenty-two (95%) hips were available for the minimum of 5 years clinical and radiographic follow-up. The mean duration of follow-up was 81 months (range, 60-104 months). The mean Harris hip score improved from 44 to 92 at the most recent follow-up. All femoral components were clinically stable with radiographic evidence of bone ingrowth. There has been no evidence of subsidence greater than 2 mm, no significant thigh pain, and no femoral revisions for any reason. Total hip arthroplasty with the Fiber Metal Taper stem demonstrates good clinical and radiographic results at midterm follow-up.

Total hip arthroplasty using proximal porous coating stem with distal sleeve: mid-term outcome

PURPOSE

To report mid-term results of total hip arthroplasty (THA) using the Opti-Fix Plus Hip System (Opti-Fix Hip), and to assess the correlations between peri-implant bone changes and the distal medullary occupancy rate.

METHODS

11 men (13 hips) and 53 women (58 hips) aged 24 to 87 (mean, 61) years underwent THA using the Opti-Fix Hip, with a modular stem and a distal sleeve, and were followed up for a mean of 6.5 (range, 4.8-9.6) years. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) hip score. Implant stability, bone changes around the implant, and the occupancy rate of the stem in the medullary space were examined radiologically. Bone changes around the implant were assessed based on the radiological evidence of a pedestal, osteolysis, stress shielding, and radiolucent lines.

RESULTS

The mean JOA score increased significantly after surgery and was maintained at the latest follow-up. Around the acetabular and femoral components respectively, 38 and 58 hips had radiolucent lines, whereas one and 54 hips developed osteolysis. A pedestal appeared in 21 hips and grade-III or higher stress shielding in 30 hips. Two hips showed loosening of the acetabular components, but none in the femoral components. Osteolysis around the stem was frequently observed in hips with poor distal medullary occupancy.

CONCLUSION

Clinical and radiological outcomes of the Opti-Fix Hip were favourable. The low incidence of osteolysis in the distal stem suggests that the proximal circumferential porous coating was effective. Minor osteolysis around the proximal stem was frequently observed, indicating early excessive wear of the polyethylene liner. Its high distal medullary occupancy rate could inhibit stem micromotion and aseptic loosening.

THA using an anatomic stem in patients with femoral head osteonecrosis

Treating young patients with femoral head osteonecrosis (ON) remains challenging. Anatomic stems were introduced in the 1980s and 1990s to improve the proximal canal fit in an attempt to enhance long-term implant survival, an important aspect of treating young patients. We began using one design in 1993 and asked three questions to confirm whether the design criteria improved outcomes in patients with ON: (1) What is the long term survivorship of these implants?; (2) What is the amount and rate of wear?; and (3) What is the incidence of osteolysis? We retrospectively reviewed 56 patients (69 hips) who underwent THA for femoral head ON with a cementless anatomic stem proximally coated with hydroxyapatite. Four patients (four hips) were lost to followup and 16 patients (19 hips) died. In the remaining 36 patients (46 hips) the minimum followup was 10 years (mean, 11.2 years; range, 10-13 years). The mean age at operation was 48.6 years. The average Harris hip score at last followup was 87 points. Worst-case survivorship was 58.1% at 13 years and best-case was 93.3%. The average linear wear of the polyethylene liner was 2.02 mm and the average annual wear was 0.18 mm per year. Thirty-seven hips (80%) had femoral osteolysis and 14 (30%) had acetabular osteolysis. One patient who had extensive femoral osteolysis and stem loosening was revised at 11.2 years postoperatively. The high rates of polyethylene wear and osteolysis are of concern.

Second-generation proximally coated titanium femoral component: minimum 7-year results

It is unclear whether resurfacing or fully porous-coated or proximally coated stems are the best femoral components for young patients. First-generation proximally coated titanium fiber-metal femoral components had a high rate of failure. We prospectively followed 56 patients (70 hips) whom we believed were at high risk for loosening of a cemented femoral component; all patients were implanted with one second-generation proximally coated titanium femoral component. Ten patients (11 hips) died and three patients (four hips) were lost to minimum followup. Three models of titanium fiber-metal acetabular component were implanted with screws. Patients were clinically evaluated using the Harris hip score. We used standardized radiographs to assess fixation status and osteolysis. Forty-four patients (55 hips) with a mean age of 45 years were followed for a minimum of 7 years (mean, 10.5 years; range, 7-15 years). No femoral component had been revised for any reason. Bone ingrowth (spot welding) was seen in 41 hips (75%) and proximal femoral osteolysis in only four hips. Reoperations for polyethylene wear were performed in seven patients (12.7%) and two patients had liner exchange for recurrent dislocation. Even with an articulating surface with considerable polyethylene wear debris, these second-generation proximally coated titanium fiber-metal femoral components had a survival rate of 100% at a mean 10.5-year followup.

Total hip arthroplasty for acute femoral neck fractures using a cementless tapered femoral stem

The purpose of this study was to evaluate the osseointegration potential and implant-related complications of cementless total hip arthroplasty with a titanium alloy collarless, tapered, wedge-shaped femoral stem with a proximal circumferential plasma-spray coating in patients with acute hip fractures. The cohort consists of 85 patients with a mean age of 78.1 years. The mean duration of follow-up was 3.8 years. Total hip arthroplasty conferred significant improvement in function for all patients. All femoral components were stable with evidence of bone ingrowth (84 hips) or fibrous fixation (1 hip). Mild thigh pain was present in 3 patients. The complications included dislocation (3 cases), intraoperative femoral fracture (2 cases), and periprosthetic femoral fracture in the postoperative period (1 case). There was one reoperation for revision of the femoral component in the patient with a periprosthetic fracture. There were 25 (29%) deaths. Cementless total hip arthroplasty using a tapered proximally coated femoral stem is a viable option for the treatment of a displaced hip fracture and preexistent arthritis.

Long-term results of the cementless porous-coated anatomic total hip prosthesis

Between January 1984 and January 1986, 131 porous-coated anatomic total hip replacements were performed in 119 consecutive patients. Of these, 100 patients (110 hips) who were alive at a minimum of 18 years after replacement were included in the study. The mean age of the patients at surgery was 48.4 years and that of surviving patients at the latest follow-up was 67.8 years. The mean duration of the clinical and radiological follow-up was 19.4 years (18 to 20).

The mean Harris hip score initially improved from 55 points before to 95 points at two years after operation, but subsequently decreased to 91 points after six years, 87 points after 11.2 years, and 85 points after 19.4 years. At the final follow-up, 23 hips (18%) of the entire cohort and 21% of survivors had undergone revision because of loosening or osteolysis of the acetabular component and eight hips (6%) of the entire cohort and 7% of survivors for loosening or osteolysis of the femoral component. Only four femoral components (4%) were revised for isolated aseptic loosening without osteolysis and two (2%) for recurrent dislocation. On the basis of these long-term results, the porous-coated anatomic femoral component survived for a minimum of 18 years after operation while the acetabular component was less durable. The findings identify the principles of uncemented joint replacement which can be applied to current practice.

Fr�hfunktionelle Ergebnisse einer Kurzschaftprothese des H�ftgelenks mit metaphys�r-intertrochant�rer Verankerung

Total hip arthroplasty has become one of the most successful standard procedures in orthopedic surgery. With a more frequent use in young and active patients bone saving procedures become more important. The goal is to save good bone stock for the revision procedure. One example of conservative femoral implants is the Mayo-stem with reported long term results. The stem design allows a metaphyseal intertrochanteric multipoint fixation for primary fixation. The surgical technique is simple. Using a transgluteal approach, the medial preparation of the femoral neck decreases significantly the irritation of the abductor tendons. In a prospective-randomized study, the early functional results with the Mayo-stem were significantly better than the results achieved with a cement-free standard stem. The Mayo-stem may not be indicated for every hip situation. Its use, however, in cases with normal anatomy contributes to save autologeous bone. Therefore, this short stem is a sensible alternative to standard stems.

Fifteen-year clinical survivorship of Harris-Galante total hip arthroplasty

We studied the long-term outcome of uncemented total hip arthroplasty using HG-I components in 90 hips (80 patients) with an average age of 57.5 years who were operated on between 1984 and 1986 at our institution. Average follow-up was 14.9 years, and no patient was lost to follow-up. Hip scores improved significantly, and there was clinical and radiographic evidence of bony ingrowth on the acetabular components in all patients. There were 11 revisions in the study population for reasons related to failure of the femoral component (8 hips), acetabular liner dissociation (2 hips), and deep infection (1 hip). At the latest follow-up, 3 femoral components were determined to be loose. No acetabular component was revised for aseptic loosening. In addition to the revisions, there were 2 reoperations, 1 for psoas tendon release, and 1 for excision of heterotopic ossification. Thus, the survivorship free of revision and free of mechanical failure for the acetabular component at 15 years was 95.7% (95% confidence interval [CI], 0.89-1.0) and 91.9% (95% CI, 0.83-0.98), respectively. The survivorship at 15 years for the femoral component was 86.8% (95% CI, 0.78-0.95) free of revision and 82.0% (95% CI, 0.71-0.92) free of mechanical failure.

Cementless titanium tapered-wedge femoral stem: 10- to 15-year follow-up

This investigation is an ongoing clinical and radiographic analysis of a titanium tapered-wedge femoral component with a proximal plasma-spray porous coating. Integral femoral stems (Biomet, Warsaw, IN) were implanted in 200 hips in 186 patients. Nineteen patients died before 10-year follow-up, and 50 patients were lost to follow-up. The mean follow-up of the remaining 129 hips was 11.6 years. Harris Hip Scores improved from 58 to 93. Thigh pain was 2.3%. Radiographic analysis revealed adaptive distal remodeling in zones 2, 3, 5, 6, and 13, with no evidence of osteolysis below the level of the calcar and the greater trochanteric region. Only 2 femoral stems were revised: 1 with suspected fibrous fixation at 7 years postoperatively and another with a broken trunion at 10 years postoperatively. A tapered titanium femoral stem with circumferential plasma-spray porous coating provides excellent long-term fixation, durable clinical outcome, and protects against osteolysis below the level of the calcar and greater trochanter.

Total hip arthroplasty using an Omniflex modular system: 5 to 12 years followup

We evaluated intermediate-term results of primary cementless Omniflex prostheses. Forty-nine patients (57 hips) with a mean age of 44 years were observed for an average of 8.6 years. The average Harris hip score was 46 points before surgery and 87 points at final followup. Revision was done in five hips (9%) in five patients. Two acetabular components (4%) were revised because of breakage of the polyethylene insert. Three femoral components (5%) were revised because of aseptic loosening. Six femoral components (10%) were radiographically loose. Overall, 11 hips (19%) were considered mechanical failures. Osteolysis was identified around three acetabular components (5%) and around 20 femoral components (35%). Nine hips (16%) had femoral osteolysis around the distal stem tip. The average annual polyethylene liner wear was 0.18 mm. These results were inferior to those using other recent cementless total hip systems.

Thirteen year results of total hip arthroplasty using a tapered titanium femoral component inserted without cement in patients with type C bone

Although cementless arthroplasty with a tapered titanium femoral component has proven reliable in young patients with excellent bone quality, studies involving patients with poor bone quality are lacking. The present study evaluates the results of total hip arthroplasty (THA) using such a femoral component in patients with Type C femoral bone. Ninety-two THAs were performed in 81 patients aged 65 years and older using a tapered titanium cementless femoral component. Follow-up in 62 patients (72 hips) averaged 13.2 years (minimum, 10 years); 19 patients were lost to follow-up. According to Door's criteria, 20 femora were classified as Type A, 19 as Type B, and 33 as Type C. No stem was revised because of stem instability, thigh pain, or osteolysis. One stem was removed because of sepsis. Six acetabula were revised because of polyethylene wear and periacetabular osteolysis. Four patients reported mild thigh pain. Radiologic signs of osseous integration for cylindrical extensively porous coated cobalt-chrome femoral components are not valid for tapered titanium designs.

Pioneering in the first century of hip replacement: experiences of a surgeon-designer

The current author offers an anecdotal history of the total joint replacement industry in North America that emerged in the 1960s and of the individuals and organizations that shaped it. The author's career as an arthroplasty pioneer, influences that helped him become interested in uncemented fixation techniques, and his impression of the requirements the industry places on emerging orthopaedic leaders also are chronicled.

Primary total hip arthroplasty with a second-generation cementless total hip prosthesis in patients younger than fifty years of age

BACKGROUND

The early experience with cementless total hip replacement led to design modifications to increase the initial press-fit and stability of the femoral component, to reduce the diameter of the femoral head, and to improve the acetabular component, including the locking mechanism of the shell and the quality of the polyethylene liner. We performed a prospective study to assess the results in young patients who had been followed for a minimum of eight years after treatment with a primary total hip arthroplasty with a second-generation cementless prosthesis.

METHODS

Eighty patients (118 hips) were included in the study. There were fifty-eight men and twenty-two women; the mean age at the time of the operation was 46.8 years (range, twenty-one to forty-nine years). We used a cementless Duraloc series-100 or 1200 acetabular component with or without screw fixation, a polyethylene liner with a 22-mm inner diameter, and a cementless Profile femoral component in all hips. The average duration of follow-up was 9.8 years (range, eight to eleven years). Clinical follow-up (with use of the Harris hip score) and radiographic follow-up were performed at six weeks; at three, six, and twelve months; and yearly thereafter. Linear and volumetric wear were measured, and bone-remodeling and osteolysis were assessed.

RESULTS

The average Harris hip score improved from 48.8 points preoperatively to 92 points at the final follow-up examination. The prevalence of transitory thigh pain was 10% (twelve of 118 hips). There was no aseptic loosening. One hip was revised because of recurrent dislocation. The average amount of linear wear was 1.18 mm, and the average wear rate was 0.12 mm/yr. Fourteen hips (12%) had osteolysis in the calcar femorale and eleven hips (9%) had acetabular osteolysis, but all of the osteolytic lesions were <1 cm (2).

CONCLUSIONS

The mechanical fixation of the anatomic fit cementless Profile stem was excellent in this study of young patients who were particularly difficult to treat because of a high prevalence of osteonecrosis and developmental dysplasia. Although there was no aseptic loosening of the components and a relatively low prevalence of osteolysis, there was a high rate of linear wear of the polyethylene liner.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series [no, or historical, control group]). See p. 2 for complete description of levels of evidence.

Ten to fifteen-year follow-up after total hip arthroplasty with a tapered cobalt-chromium femoral component (tri-lock) inserted without cement

BACKGROUND

Fixation of the femoral component of a total hip arthroplasty without cement has had variable results. While tapered stems appear to have consistently good results, the duration of follow-up in many series has been relatively short. The purpose of this study was to present a longer-term (ten to fifteen-year) follow-up after total hip arthroplasty with insertion of a tapered femoral component without cement.

METHODS

Sixty-seven total hip arthroplasties were performed with insertion of a tapered, cobalt-chromium femoral component without cement in fifty-eight patients from 1983 to 1986. Thirteen patients (fifteen hips) died prior to the fifteen-year follow-up examination, and three patients (three hips) were lost to follow-up after ten years, leaving forty-two patients (forty-nine hips) who were followed clinically for a mean of fifteen years. Thirty-seven of the forty-nine hips were followed radiographically for fifteen years, and the remaining twelve were followed for a minimum of ten years.

RESULTS

The mean preoperative Charnley score was 3.0 points for pain, 2.7 points for function, and 3.2 points for motion. At the time of the final follow-up, the mean scores were 5.6, 5.6, and 5.2 points, respectively. Although no preoperative Harris hip scores were available, the mean score at the time of the latest follow-up was 92 points (range, 78 to 100 points). There were no revisions because of isolated aseptic loosening of the femoral component (although revision because of aseptic loosening of the acetabular component led to femoral component revision in seven hips). Two femoral components showed radiographic evidence of instability. At fifteen years, the prevalence of thigh pain was 2%. No femoral component that was thought to be stable, with bone ingrowth at two years, lost fixation.

CONCLUSIONS

The design features of this cobalt-chromium femoral component (i.e., the collarless, tapered, wedge fit with circumferential porous coating) are thought to be crucial to the achievement of the good-to-excellent results seen in this study.

Two different cementless femoral components in primary total hip arthroplasty

The results of first (51 Harris-Galante stems with an average follow-up of 12.3 years) and second generation (53 MultiLock stems with an average of 6.4 years) cementless femoral stems in total hip replacement were analysed. Ten Harris-Galante stems were revised (9.8% at 8 years and 22.8% at 13 years) and one unstable MultiLock stem (2.6% at 8 years). Thirty-seven Harris-Galante and 45 MultiLock stems were osseo-integrated. Femoral osteolysis was seen in 21 Harris-Galante (26.6% at 8 years and 43.7% at 13 years) and in 3 MultiLock stems (8.0% at 8 years). At intermediate follow-up, second generation stems show less bone remodelling changes than first generation stems at the same interval. Distal osteolysis and pronounced stress-shielding have not been encountered in second generation stems. (Hip International 2002; 12: 289-302).

Pregnancy after total hip arthroplasty

BACKGROUND

Younger patients are having total hip arthroplasty now, and a woman who has had such a procedure may want to become pregnant. The purposes of this study were to report on a series of women who had completed a pregnancy after a total hip arthroplasty and to determine if pregnancy affects the function and longevity of the prosthesis.

METHODS

Five women, with a total of seven uncemented total hip replacements, had six successful pregnancies. The mean age at the arthroplasty was twenty-nine years (range, twenty-two to thirty-eight years), and the mean time from the hip arthroplasty to the pregnancy was 2.5 years (range, one to seven years). These patients (Group A) were compared with a matched group of five women with a total of eight uncemented total hip prostheses (Group B) who had not completed a pregnancy. The mean follow-up time was eight years (range, two to thirteen years) for Group A and seven years (range, two to twelve years) for Group B. Patients were clinically evaluated with the Harris hip score. Radiographs were evaluated for component fixation and osteolysis.

RESULTS

The five women completed a total of six successful pregnancies. One patient, with a bilateral total hip arthroplasty, had two successful pregnancies, 2.5 years apart. Three children were delivered vaginally (with the mother in the lithotomy position) and three, by cesarean section. There were no complications related to the total hip arthroplasty after delivery. The mean weight gain during the pregnancy was 13 kg (range, 8 to 14.2 kg). In Group A, the mean Harris hip score was 94 points prior to the pregnancy and 97 points at the time of the most recent follow-up. In group B, the mean Harris hip score was 91 points at one to two years after the arthroplasty and it was unchanged at the time of the most recent follow-up. There were six excellent results and one good result of the hip arthroplasty in Group A and five excellent and three good results in Group B. The mean total arc of hip motion was 217 degrees in Group A before the pregnancy and 241 degrees at the time of the most recent follow-up. The mean total arc of hip motion was 193 degrees in Group B at one to two years postoperatively and 190 degrees at the time of the most recent follow-up. The difference in the total arc of hip motion between the two groups at the latest follow-up evaluation was significant (p = 0.025). There were no reoperations in either group. Radiographs showed osteolysis of the femur in three hips in Group A and three hips in Group B.

CONCLUSIONS

It appears that successful pregnancy and normal vaginal delivery can occur safely after total hip arthroplasty. The overall result, function, and radiographic appearance after the total hip arthroplasty was not adversely affected by pregnancy in this small group of patients.

The Harris-Galante total hip arthroplasty: a minimum 8-year follow-up study

A total of 93 Harris-Galante Porous I (HGP- I) prostheses were analyzed with a mean follow-up of 10.2 years. Thigh pain (28 hips) correlated with unstable fixation (P<.005), female gender (P<.045), young age (P<.05), poor distal femoral fill (P<.002), subsidence (P<.0001), and osteolysis (P<.05). Thirteen stems and 6 metallic shell cups were revised. Kaplan-Meier analysis showed 13-year survival rates of 92.5% +/- 5.8% for the metallic shell cup, 79.7% +/- 13% for the HGP-I cup, and 76.3% +/- 14.0% for the stem. Five polyethylene liners were changed because of wear >1 mm. Radiographic loosening occurred in 8 cups. Radiographic bone ingrowth was present in 54 stems, stable fibrous fixation was present in 24 stems, and unstable fixation was present in 15 stems. The mean polyethylene wear was 0.17 mm/y. Eleven hips (11.8%) had acetabular osteolysis, and 24 (25.8%) had femoral osteolysis, the latter being more frequent in unstable stems (P<.007). The HGP-I metallic cup shows better clinical and radiographic results than the stem, which frequently is associated with pain, unstable fixation, and osteolysis. Excessive polyethylene wear is frequent.

Dislodgment of polyethylene liners in first and second-generation Harris-Galante acetabular components. A report of eighteen cases

BACKGROUND

Dislodgment of the polyethylene liner is an increasingly common complication following total hip arthroplasty. The purposes of this study are to present the results in a series of patients with this complication and to analyze the mode of failure.

METHODS

Between November 1995 and January 2001, eighteen patients who had had a total hip arthroplasty presented with dislodgment of the polyethylene liner from a Harris-Galante metal acetabular shell. The medical records, radiographs, operative notes, and retrieved components were reviewed. In addition, scanning electron microscopy was used to study the fractured surfaces in a shell that had four broken tines.

RESULTS

The components had been in situ for an average of seven years (range, three to eleven years). Seventeen components were second generation, and one was first generation. Symptoms developed spontaneously in sixteen patients, during sexual intercourse in one, and following a fall on the hip in one. Radiographs showed eccentric positioning of the head in all of the hips and broken tines in six. All of the shells were well fixed. Treatment consisted of revision of the shell in four patients, exchange of the liner in four, cementation of a new liner into the shell in seven, and cementation of an all-polyethylene cup in three. The liners had severe damage of the rim. Scanning-electron microscopy of the fractured surfaces of four tines revealed a fatigue pattern.

CONCLUSIONS

We believe that, as the liner wears and becomes loose because of an inadequate locking mechanism, progressive micromotion occurs and the load increases on the polyethylene rim until it deforms and/or fractures. Subsequently, nothing prevents the liner from rotating out of the shell. As this mechanism of failure appears to include fatigue failure of the locking tines and wear of the liner, this complication is likely to increase as the components age in situ.

Cementless primary total hip arthroplasty with a tapered, proximally porous-coated titanium prosthesis: a 4- to 8-year retrospective review

A consecutive series of 100 primary total hip arthroplasties were performed at a single institution on 87 patients using a cementless collared titanium press-fit stem. Of patients, 87% received a hemispheric porous-coated cup, and 13% received a nonmodular titanium fibermesh press-fit cup. Ten hips were excluded from the longer-term evaluation: 6 were lost to follow-up, and 4 patients were deceased. Ninety hips, with an average follow-up of 81 +/- 12 months, were retrospectively reviewed. The average postoperative hip score was 94, compared with an average preoperative hip score of 42. No postoperative infections were observed, but there were 2 cases of postoperative dislocation (2%) and 1 case of thigh pain (1%) at last follow-up. There were 2 revisions, both for cup failures. There were no femoral component loosenings or revisions. There was no evidence of stem subsidence or instability. These midterm results are encouraging with this stem design.

The Harris-Galante uncemented femoral component in primary total hip replacement at 10 years

Eighty-eight primary femoral reconstructions in 80 patients were performed with the Harris-Galante uncemented femoral stem by 1 surgeon between March 1984 and December 1987. Seventy-seven femoral components in 72 patients were followed for an average 126 months or until femoral revisions. The average age at operation was 54 years (range, 30-70 years). Fifty-two patients were men, and 20 were women. The present article documents the incidence of femoral osteolysis and femoral revision in this series of this type of femoral component at an average of 10 years. Fifteen femoral components (15 of 77, 19%) were revised, 14 (14 of 77, 18%) for aseptic loosening, osteolysis, or fracture through osteolysis. The remaining 62 femoral components were functioning well (average Harris Hip Score 89 points), but 7 (11%) were loose, and 32 (52%) had femoral endosteal lysis. Overall, 19 (25%) were revised or loose, and 46 (46 of 77, 60%) had lysis. The high incidence of femoral lysis and aseptic loosening with this early design of uncemented femoral stem continues to increase at 10-year follow-up.

Total hip replacement with an entirely hydroxyapatite-coated prosthesis: 5 years' follow-up of 94 consecutive hips

The first 100 consecutive entirely hydroxyapatite (HA)-coated hip arthroplasties in 86 patients (mean age, 56.2 years [range, 32-73 years]; female-to-male ratio, 75:25) were followed with standardized radiographs annually up to 5 years. All components developed 100% intimate bone-implant contact, being gradually reduced to 99.5%+/-3.8% by 2 partial periacetabular lines and on the femoral side to 94.0%+/-6.1% and 96.5%+/-5.2% in the frontal and lateral planes by lines along 75 stems, mostly in zones 1 and 8. Bone formation took place adjacent to the prostheses regularly, with gap filling and comprehensive periprosthetic bone remodeling, stabilizing at 3 years. No adverse stress shielding was found. The clinical results were excellent without thigh pain. We believe that all components were bonded directly to bone, promoted by the reliable primary fixation and the osteoconductive effect of HA.

Omnifit cementless total hip arthroplasty. A 10-year average followup

Seventy-six hips in 67 patients were evaluated an average of 119 months (range, 61-150 months) after total hip arthroplasty with porous coated Omnifit femoral and acetabular components. The patients were young (average age, 45 years), and most were male (67%). Two stems and one cup were revised for aseptic loosening, for aseptic revision rates of 2.6% on the femoral side and 1.3% on the acetabular side. Thigh pain was present in three cases, one of which was activity limiting. Twenty-five (35.7%) hips had evidence of osteolysis confined to proximal Gruen Zone 1 or 7 or to the acetabulum (22 proximal femoral, three both). There were no cases of intramedullary osteolysis in surviving stems. Thirteen (17.1%) hips have undergone reoperation for bone grafting of progressive proximal osteolysis without component revision, at an average 93 months after the total hip arthroplasty. At an average 40 months after reoperation, all stems remain well fixed, and there has been no recurrence of osteolysis of grafted femoral lesions. These results suggest that a circumferentially proximally porous coated femoral component in cementless total hip arthroplasty can provide stable fixation for as long as 12 years after implantation and caseal the canal from distal osteolysis. Serious concerns remain about the incidence of proximal femoral osteolysis.

Primary total hip arthroplasty with the AML total hip prosthesis

Primary total hip arthroplasty using an uncemented AML total hip prosthesis (trispiked cup and a 4/5 porous coated stem) was performed in 50 patients (52 hips). The average age of the patients at the time of surgery was 47.6 years (range, 19-68 years), and the diagnosis was osteonecrosis of the femoral head in 18 hips, osteoarthritis in 16, fracture of the femoral neck in 14, osteoarthrosis secondary to childhood pyogenic arthritis in two, childhood tuberculous arthritis in one, and traumatic arthritis in one. The average followup was 11.3 years (range, 11-12 years). The average preoperative Harris Hip Score was 59 points, which improved to 90 points. Twenty-five (48%) hips had excellent results, 14 (27%) had good results, three (6%) had fair results, and 10 (19%) had poor results. The overall rate of revision was 15% (eight hips). The rate of revision of the femoral component was 2% (one hip), and the rate of revision of the acetabular component was 15% (eight hips). Twenty (38%) hips had acetabular and femoral osteolysis. Nine (17%) hips had femoral osteolysis only. Thirty-four (65%) hips had an average of 3.3 mm (range, 2-12 mm) of wear in the polyethylene liner. The average wear rate was 0.29 mm (range, 0.17 to 1.04 mm) per year.

The hemispherical Harris-Galante acetabular cup, inserted without cement. The results of an eight to eleven-year follow-up of one hundred and sixty-eight hips

We studied the results for 168 available hips from a series of 324 consecutive primary total hip arthroplasties that had been performed with insertion of a Harris-Galante-I acetabular component without cement. The acetabulum had been reamed in a so-called line-to-line manner, and the cup had been fixed with one to four screws. A femoral component with a modular alumina-ceramic head had been inserted with cement in all hips. The median duration of follow-up was 112 months (range, 101 to 131 months). Of the original 324 hips, 109 could not be included in the clinical and radiographic follow-up because the patients had died and thirty could not be included because the patients were not available for examination. Seventeen hips had had a revision of the acetabular cup: five, because of infection; five, because of dislocation; three, because of aseptic loosening; and four, because of technical failure. This left 168 hips for clinical and radiographic follow-up; of these, fifteen had had a revision of the femoral component only. Of the remaining 153 hips, which had not had a revision, 147 (96 percent) were considered by the patient to have a satisfactory, good, or excellent result. One hip was found to have a loose cup on radiographic evaluation and was therefore considered to have failed, but the clinical function was good. We concluded that, with an overall rate of aseptic loosening of 1 percent (four of 324) after an intermediate (ten-year) duration of follow-up, use of this cup has good results.

The pathogenesis of bone loss following total knee arthroplasty

Bone loss following total knee arthroplasty (TKA) may be focal or diffuse. It may be caused mechanically, either by unloading of the bone leading to disuse osteoporosis, or by overloading of the bone leading to trabecular fractures and bone destruction. Osteolysis, instigated by an inflammatory reaction to particulate wear debris, is an important and common cause of bone loss after TKA. Less common, though sometimes dramatic, causes of bone loss are infection and osteonecrosis.

Unusual cause of third-body wear in total hip arthroplasty

A case of severe osteolysis caused by third-body wear using a Harris-Galante II cup (Zimmer, Warsaw, IN) is reported. The prosthesis was inserted in a 23-year-old man 4.5 years ago. At revision, 3 triangular tynes of the acetabular shell rim were found embedded in the polyethylene liner.

Three-dimensional polyethylene wear of a press-fit titanium prosthesis. Factors influencing generation of polyethylene debris

Between 1985 and 1990, 108 consecutive Harris-Galante I (Zimmer, Warsaw, IN) total hip arthroplasties were performed by four surgeons at a single hospital. At the time of follow-up evaluation, 80 hips were available for review. The mean rate of linear wear was 0.15 mm/y, mean rate of three-dimensional femoral head displacement was 0.21 mm/y, and mean rate of volumetric wear was 121 mm3/y. Eight hips (10%) in this series had radiologic osteolysis around either the femoral or acetabular component. A significantly greater volumetric wear rate was found in patients who were younger, those with a higher activity level, those who received a 32-mm-diameter femoral head, and those with vertical orientation of their acetabular component. No relationship could be made with patient weight, gender, Harris hip score, or cup diameter.

Prospective study of 100 consecutive Harris-Galante porous total hip arthroplasties. 4- to 8-year follow-up study

This prospective study evaluates 100 consecutive Harris-Galante Porous (Zimmer, Warsaw, IN) noncemented femoral prostheses 4 to 8 years after surgery. Two femoral components were revised for aseptic loosening. The mean Harris hip score was 56 before surgery and 92 at final follow-up evaluation, with moderate thigh pain seen in 6%. Ingrowth was classified as bony (89%), stable fibrous (8%), and unstable (3%). A pedestal formed in 18%, measurable subsidence occurred in 22%, and endosteal erosion occurred in 12%. Patients with pedestal formation had a higher incidence of unstable growth pattern (P < .05). Patients with bony ingrowth had a lower mean subsidence (0.38 mm) than those with fibrous stable ingrowth (3 mm) and unstable ingrowth (7.5 mm) (P < .05). Thigh pain correlated with the type of ingrowth, and endosteal erosion with the linear polyethylene wear. Survival analysis was 97.5% at 8 years.

The bone-implant interface of femoral stems with non-circumferential porous coating

A histological study was performed of the bone-implant interface of fifteen titanium-alloy femoral stems with porous coating limited to three proximal areas that did not cover the full circumference of the device. The specimens were obtained at autopsy from ten cadavera at a mean of forty-six months (range, one to eighty-nine months) after the implant had been inserted without acrylic cement. The volume fraction of bone within the porous spaces (the percentage of the porous space that was filled with bone) and the extent of bone ingrowth (the percentage of the porous-coated surface covered with in-grown bone that was more than one-half fiber-diameter deep, as measured from the outer surface of the porous coating), were determined with histomorphometric methods. Eleven of the fifteen stems had bone within the porous coating that was in continuity with the surrounding medullary bone. The mean volume fraction of bone ingrowth in these specimens was 26.9 per cent (range, 12.2 to 61.0 per cent), and the mean extent of bone ingrowth was 64.3 per cent (range, 28.6 to 95.2 per cent). Both of these parameters increased with time. In the other four stems, the bone lacked continuity with the surrounding trabecular bed. Two of these stems had a limited amount of bone within the porous coating, and two stems (from one patient) had no bone ingrowth. Periprosthetic membranes surrounded by a shell of trabecular bone covered the uncoated surfaces of the stems. The membranes of implants that had been in situ for eight months or more demonstrated polyethylene wear debris, and other particles generated at the level of the joint, within histiocytes throughout the length of the femoral stem.

CLINICAL RELEVANCE

The findings in this study are relevant to the utilization and mechanisms of failure of femoral stems inserted without cement. Bone ingrowth and the resulting stability of the implant can be achieved with porous-coated stems. However, the extent of the surface that is porous-coated must be sufficient to prevent trabecular fracture as a secondary mechanism of loosening. Interruptions in the circumferential extent of the porous surface are associated with the formation of periprosthetic membranes, which provide a pathway for migration of particulate wear and corrosion products to the distal part of the stem. A circumferential coating may retard the access of particles and thus decrease the possibility of diaphyseal osteolysis.

Porous-coated acetabular components with screw fixation. Five to ten-year results

The results of 136 consecutive primary total hip arthroplasties performed by one surgeon with the Harris-Galante-I porous-coated acetabular component were reviewed at a mean of seven years (range, five to ten years). In all hips, the outer diameter of the acetabular component was the same as the diameter of the final reamer used in the preparation of the acetabulum. However, this reamer was used only briefly at the rim of the acetabulum, and therefore the components had so-called press-fit stability. A mean of four screws (range, three to six screws) were used for additional fixation of the component. The clinical evaluation was performed with use of the Harris hip score. Standardized anteroposterior radiographs of the pelvis were assessed for migration of the component, radiolucent and radiodense lines, linear wear of the polyethylene, and osteolysis. No acetabular component had been revised for loosening and none were radiographically loose at the time of the most recent follow-up evaluation. There were no complications related to the use of the screws, and no screw had bent or broken. A non-progressive radiolucent line was seen in one acetabular zone in thirty-four hips (25 per cent) and in two acetabular zones in six hips (4 per cent). No hip had a radiolucent line in all three acetabular zones. The mean rate of linear wear of the polyethylene was 0.1 millimeter per year. There was no dissociation of the acetabular liner from the metal shell. Two hips (1 per cent) had asymptomatic osteolysis in the ischium and adjacent to the rim of the acetabular component; this was treated with grafting at the site of the lesion and exchange of the femoral head and the worn polyethylene liner. Five femoral components inserted without cement and one inserted with cement were revised because of loosening. The data suggest that, at a mean of seven years, fixation of this porous-coated component was uniformly excellent. The low prevalence of radiolucent lines and the absence of loosening are probably related, in part, to the technique of implantation. The low prevalence of polyethylene wear and pelvic osteolysis is a notable improvement compared with the results of arthroplasty with other porous-coated acetabular components. Although the results of the present study are encouraging, longer follow-up is necessary to determine the prevalence of late loosening and osteolysis.

Relative effects of wound healing and mechanical stimulus on early bone response to porous-coated implants

We hypothesized that early bone adaptation to well fixed porous-coated implants is influenced more by wound healing than by mechanical loading. To test this hypothesis, two groups of dogs with identical, hydraulically controlled porous-coated implants interference fit within distal femoral trabecular bone were used. One group had no load: the other had 35 N of load applied to the implants. At 5 weeks after surgery, the resulting adaptation of bone around the implants was quantified on a cellular basis by cytochemical analysis of type-I procollagen synthesis and on a structural basis using three-dimensional micro-computed tomography imaging. The percentage of trabecular surfaces covered by osteoblasts expressing type-I procollagen was significantly increased in bone surrounding the implant in both groups compared with contralateral control bone tissue. There was no difference between the groups with no load or 35 N of load. In addition, measures of trabecular bone structure did not differ significantly between the load and no-load groups. Taken together, these results suggest that wound healing plays a much greater role in the early response of bone to well fixed porous-coated implants than does mechanical stimulus.

Host-bone response to porous-coated cobalt-chrome and hydroxyapatite-coated titanium femoral components in hip arthroplasty. Dual-energy x-ray absorptiometry analysis of paired bilateral cases at 5 to 7 years

Uncemented porous-coated cobalt-chrome femoral stems have produced satisfactory short-term clinical results, although slightly inferior to the results of cemented total hip arthroplasty. Proximal femoral bone resorption, osteolysis and fibrous ingrowth have been reported with porous-coated stems. Hydroxyapatite-coated stems and titanium stems have been introduced to avoid these findings through improved fixation. Dual-energy x-ray absorptiometry allows quantitative examination of bone density changes after uncemented total hip arthroplasty. This study examines the host-bone response to hydroxyapatite-coated titanium and porous-coated cobalt-chrome stems of identical geometry in three paired bilateral cases at 5 to 7 years. Distinctly different patterns of femoral bone mineral density changes were observed with the two stem designs. The authors conclude that dual-energy x-ray absorptiometry is a promising technique allowing noninvasive analysis of uncemented stem fixation, and that the data from this study suggest improved fixation and stress transfer with hydroxyapatite-coated titanium stems.

The Wisconsin noncemented femoral stem. A prospective study with 5 to 9 years of follow-up evaluation

In an attempt to decrease aseptic loosening, total joint components are now being used without cement. Most components are designed to achieve fixation biologically. The radiographic results of 144 primary uncemented total hip arthroplasties and the clinical results of 89 arthroplasties that were performed using a proximally porous-coated titanium alloy femoral stem between November 1983 and June 1989 are reported. On the acetabular side, a threaded component or a hemispherical porous-coated component was used. The patients were followed prospectively for 5 to 9 years postsurgery. During the study period, the threaded acetabular component had a high failure rate. Because it was not possible to determine accurately from which component a particular sign or symptom arose, clinical analysis was restricted to only those hips without a failed or revised cup. Eighty-nine hips in 71 patients with a minimum follow-up period of 5 years were available for clinical review. Radiographic review of the femoral stem was completed on all hips with 5 or more years of radiographic follow-up evaluation regardless of the status of the acetabular component. One hundred twelve hips in 85 patients were analyzed radiographically. At a latest mean follow-up period of 6.7 years, the mean Iowa hip score was 91.4 +/- 8.0 with a 5.4% incidence of thigh pain. Throughout the follow-up period, the patients with thigh pain had a statistically lower mean Iowa pain subscore when compared with those patients without thigh pain (P=.0001). Endosteal erosion was seen in two hips (1.8%) and longitudinal loss of the medial neck greater than 2 mm was noted in two hips. One femoral stem was revised for aseptic loosening. The clinical results of this femoral stem equal or exceed the published accounts of other arthroplasties. The results indicate that the stem is associated with good clinical results, minimal bone loss, and little osteolysis. Continued follow-up evaluation of patients with this femoral stem is necessary to assess the durability of these encouraging results.

Prostheses for primary total hip replacement. A critical appraisal of the literature

Eighty-one published papers on the performance of prostheses in total hip replacement were appraised. Sound methodology was demonstrated in 1 of 8 randomized controlled trials and 4 of 17 nonrandomized comparative studies. Of 56 case series without controls, 32 met the appraisal criteria, but these are intrinsically less useful. The published literature does not provide solid evidence for the superiority of cement-free or hybrid prostheses over modern cemented types.

Cemented versus uncemented socket in hip arthroplasty. A radiostereometric study of 60 randomized hips followed for 2 years

60 patients with arthrosis who received a Charnley total hip replacement were randomly assigned to either an uncemented porous Harris-Galante type I socket or a cemented all-polyethylene Charnley socket. Socket migration and rotation were studied by radiostereometry (RSA) for 2 years. After 2 years, all sockets were still in situ. There was no difference in migration or rotation between the 2 socket designs, nor was there any difference in pain or function. We conclude that the initial fixation of the Harris-Galante socket resembles that of the Charnley socket.

Migration of acetabular components, inserted with and without cement, in one-stage bilateral hip arthroplasty. A controlled, randomized study using roentgenstereophotogrammetric analysis

Twenty-one patients who had primary osteoarthrosis were managed with a bilateral total hip arthroplasty with insertion of a Charnley femoral component. In each patient, one hip was randomly allocated to have a Harris-Galante acetabular component inserted without cement, and the contralateral hip was treated with an all-polyethylene Charnley acetabular component fixed with cement. The clinical result was satisfactory in all patients. All forty-two hips were followed, with respect to migration of the acetabular component, with use of roentgenstereophotogrammetric analysis for a median of twenty-seven months (range, twenty-three to forty-nine months). Each patient served as his or her own control. Maximum migration in any direction was 1.7 and 2.1 millimeters, and maximum rotation was 2.2 and 2.0 degrees for the Harris-Galante and Charnley acetabular components, respectively. There was no significant difference in migration between the two designs of acetabular components (p = 0.98, p = 0.75, and p = 0.06 for the transverse, longitudinal, and sagittal axes, respectively). However, the Harris-Galante acetabular components rotated significantly more than the Charnley acetabular components around two of the three axes (p = 0.008, p = 0.08, and p = 0.03 for the transverse, longitudinal, and sagittal axes, respectively). The Charnley hip implant has been used clinically for a long time, with successful results. Comparison of new designs of implants with the Charnley prosthesis is therefore important. Roentgenstereophotogrammetric analysis provides a potential for detection of problems with fixation at an early stage rather than after long-term follow-up. No major difference in terms of skeletal fixation was found between the two designs of components after short to medium-term follow-up.