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

Average 22-Year Results of Total Hip Arthroplasty Using Harris-Galante Prosthesis in Patients under 50 Years

Background

The Harris-Galante (HG) prosthesis is a first-generation, cementless total hip arthroplasty (THA) prosthesis. Considering the recent increase in the demand for THA in young patients and their life expectancy, a study with a follow-up duration of longer than 20 years in a young population is needed. Therefore, we evaluated the long-term clinical and radiographic results after cementless THA using the HG prosthesis in patients younger than 50 years.

Methods

A total of 61 THAs performed using the HG with a minimum follow-up of 10 years were included. There were 38 men and 11 women with an average age of 46 years and the mean follow-up duration was 22 years. Clinical evaluation included modified Harris Hip Score (HHS) and radiographic analysis consisted of cup inclination, anteversion angle, component stability, osteolysis, liner wear rate, wear-through, liner dissociation, and heterotopic ossification. Complications included recurrent dislocation, periprosthetic femoral fracture, and periprosthetic joint infection. Survivorship analysis included cup and stem revision for aseptic loosening, as well as any revision.

Results

The HHS improved from 46.5 preoperatively to 81.8 postoperatively (p < 0.001). The average linear wear rate was 0.36 mm/yr. A total of 34 hips (56%) were revised: stem revision in 10 (16.4%), cup revision in 9 (14.8%), exchange limited to bearing surface in 8 (13.1%), and revision of all components in 7 (11.5%). Estimated survivorship at 34 years postoperatively was 90.9% for cup revision for aseptic loosening, 80.5% for stem revision for aseptic loosening, and 22.1% for any revision.

Conclusions

THA using the HG prosthesis showed satisfactory estimated survivorship of the acetabular and femoral components at 34 years postoperatively with good clinical outcomes. Bearing-related problems, such as osteolysis and liner dissociation, accounted for 56% of revision operations and were concerns in patients younger than 50 years.

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.

Mid-term results of an uncemented tapered femoral stem and various factors affecting survivorship

OBJECTIVE

CLS stem is commonly used today in primary hip arthroplasty, but only a few studies have evaluated their outcome in young high demanding patients. In Indian scenario, many patients require squatting and sitting cross-legged as part of their daily activities placing excessive load on the joint. We evaluated (I) Mid-long term functional and radiological results (II) Influence of age, gender, diagnosis, stem alignment, Canal fill index (CFI) on the outcome (III) Kaplan-Meier survivorship using revision for any reason or for aseptic loosening as an endpoint.

METHODS

Retrospective evaluation of 64 THA in 54 patients operated between July 2000 to July 2011 using CLS stem was done. Mean follow-up was 10.3 years (5-14.9 years) with 5 patients lost to follow-up and 4 patients died. Mean age at surgery was 46.8 years (18-78 years).

RESULTS

Mean Harris hip score was 89.4 (72-100). Thigh pain was present in 4 hips which were not associated with the sizing of the stem (p = .489). Stable fixation by bony ingrowth was seen in 53 hips (96.4%) and by fibrous ingrowth in 2 cases (3.6%) with no case of loosening seen. Stress shielding was seen as Grade II in 17 hips (30.9%), Grade III in 3 hips (5.4%). Pedestal formation was seen in 9 hips (16.4%) which were statistically associated with varus alignment and CFI < 80. No stem revision was performed with stem survivorship of 100%.

CONCLUSION

The mid-term survival rates and good clinical-radiological outcomes of CLS stem in high demanding Indian population were excellent.

Early aseptic loosening of the Tritanium primary acetabular component with screw fixation

Ultraporous acetabular components were developed to improve osseointegration and fit for increased longevity and better outcomes after total hip arthroplasty. There is a paucity of literature detailing this acetabular component's clinical performance, with even less detailing those with screw fixation. We identify 5 patients at our institution who underwent revision total hip arthroplasty for early aseptic acetabular cup loosening of an ultraporous acetabular component known as the Tritanium primary cup with secondary screw fixation. They all presented with groin and hip pain after index surgery and underwent follow-up radiographic examination consistent with component loosening requiring revision surgery. This case series reports on the risk of early acetabular cup loosening and its associated clinical presentation, workup, and surgical management in patients with the Tritanium primary cup augmented with screws.

Effect of stem alignment on long-term outcomes of total hip arthroplasty with cementless Bi-Metric femoral components

We investigated the effects of varus-valgus alignment on the long-term outcomes after cementless total hip arthroplasty (THA) using a porous coated version of Bi-Metric^® femoral stems. The Kaplan-Meier survival analysis was performed in 71 hips. The survival rate with femoral revision for aseptic loosening as the end point was 100% at 17 years. Nevertheless, the initial stem alignment was more valgus in patients with the Engh grade III-IV stress shielding than patients with the Engh grade I-II. Our results suggest that valgus misalignment of cementless Bi-Metric stem might be a potential risk factor for the progression of stress shielding.

Total Hip Arthroplasty With an Uncemented Tapered Femoral Component in Patients Younger Than 50 Years of Age: A Minimum 20-Year Follow-Up Study

BACKGROUND

Previously, we reported the mean 16-year results of primary uncemented total hip arthroplasty using a tapered femoral component in patients <50 years. The purpose of this study was to update our previous report using the Taperloc femoral component in young patients who had been followed for a minimum of 20 years postoperatively.

METHODS

Between 1983 and 1990, 108 consecutive uncemented total hip arthroplasties were performed in 91 patients of age <50 years, with use of the Taperloc femoral component. Every patient was followed for a minimum of 20 years after surgery or until death. At a mean of 25 (range, 20-29 years) postoperatively, 76 patients (91 hips) were living. The Harris Hip Score, radiographic results, complications, and Kaplan-Meier survivorship were evaluated.

RESULTS

In the entire cohort of 108 hips, 9 femoral components (8%) have been revised, none for aseptic loosening. Five well-fixed stems were removed during acetabular revision, 3 stems were revised for infection, and 1 stem was exchanged because of a peroneal nerve palsy. Distal femoral osteolysis was identified around 1 hip. With failure defined as stem removal for any reason, implant survival was 90% (CI = 82-95) at 29 years. With failure defined as stem removal for aseptic loosening, implant survival was 100% at 29 years.

CONCLUSION

Primary total hip arthroplasty with the Taperloc femoral component in young patients was associated with a high rate of survival at 29 years.

Thirteen year follow-up of a cementless femoral stem and a threaded acetabular cup in patients younger than fifty years of age

PURPOSE

Compared to older patients undergoing total hip arthroplasty (THA) younger patients are considered to be more active, thereby exposing the implant to significantly higher loads over a much longer period of time. Additionally, cases of secondary osteoarthritis caused by hip dysplasia, femoral head necrosis or rheumatic diseases are much more frequent than among the average patient population. Therefore, durable implant fixation and low wear rates are extremely important to achieve good long-term implant survival in this group of patients.

OBJECTIVE

The aim of this retrospective study was to evaluate the mid- to long-term survival of a cementless femoral stem (Zweymüller® SL stem) and a threaded cup (Bicon SL®) in patients younger than 50 years of age.

METHODS

Therefore, a consecutive series of 100 patients (111 hips) aged 50 years or younger (range: 30 to 50 years) was analysed at a mean follow up of 13.5 years. Follow-up assessment included physical examination and radiographic workup. Hip disability osteoarthritis and outcome score (HOOS) and Harris hip score (HHS) were used to evaluate the pre- and post-operative functional outcome, respectively. Patient satisfaction with the surgical result was assessed by standardized questionnaires.

RESULTS

The overall survival rate with any revision as endpoint was 96.8 % (95 % CI: 90.5 % to 98.9 %) at ten years. Gender, operation time and the occurence of osteolyses had no influence on joint function or patient satisfaction. We recorded an overall failure rate of 7.4 % (six cases). In four cases (5 %) the prosthesis had to be revised due to aseptic loosening of the cup after 12 years, eight years, 12 years and 11 years, in one case (1.2 %) recurrent luxation led to a revision operation (acetabular cup and head) after three years of primary implantation. In one case an implant failure was recorded (acetabular cup breakage after eight years of implantation). We recorded the occurence of asymptomatic radiolucent lines of the cup in 21 % and of the stem in 35 % in our series. The HOOS was influenced by the presence or abscence of radiolucent lines of the stem. Patients with radiolucent lines of the stem had a median HOOS score of (74 points) compared to those without radiolucent lines (89 points). Other factors, such as "diagnosis led to operation" and "previous operations" had no influence on the HHS and HOOS.

CONCLUSION

Our study demonstrates excellent long-term survival of cementless femoral stem in combination with a threaded cup in young patients undergoing total hip arthroplasty.

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.

Material Science in Cervical Total Disc Replacement

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

Long-term (20- to 25-year) results of an uncemented tapered titanium femoral component and factors affecting survivorship

BACKGROUND

Uncemented femoral components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the third decade.

QUESTIONS/PURPOSES

We evaluated (1) survivorship using femoral revision for any reason as the end point; (2) survivorship using femoral revision for aseptic loosening as the end point; and (3) patient-related and surgical risk factors for aseptic stem loosening at a minimum 20-year followup with an uncemented tapered titanium stem.

METHODS

We reviewed the clinical and radiographic results of 354 THAs in 326 patients performed between January 1985 and December 1989 using an uncemented grit-blasted, tapered titanium femoral stem. Mean age at surgery was 57 years (range, 13-81 years). Kaplan-Meier survivorship analysis was used to estimate long-term survival. Minimum followup evaluation was 20 years (mean, 22 years; range, 20-25 years); at that time, 120 patients (127 hips) had died, and four patients (five hips) were lost to followup. Multivariate survival analysis using a Cox regression model was performed.

RESULTS

Survivorship at 22 years with revision of the femoral component for any reason as the end point was 86% (95% confidence interval [CI], 81%-90%). Survivorship for femoral revision for aseptic loosening as the end point was 93% at 22 years (95% CI, 90%-96%). Undersized stems (canal fill index≤80%) and stems in hips with cup revision were at higher risk for aseptic loosening (hazard ratio, 4.2 and 4.3, respectively). There was a high rate of acetabular revision in this series (38%), mostly related to smooth-threaded, cementless sockets.

CONCLUSIONS

Uncemented femoral fixation was reliable into the third decade. Age, male sex, and diagnosis were not associated with a higher risk of aseptic loosening.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Subsidence of collarless uncemented femoral stems in total hips replacements performed for trauma

INTRODUCTION

Collarless, uncemented, femoral stems give excellent results in elective hip replacements but few studies look at outcomes in trauma patients. The presence of osteoporosis and subsequent widened femoral canal may compromise the mechanical stability of uncemented femoral stems resulting in early subsidence. The aim of this study was to assess whether early subsidence occurred when collarless uncemented stems were used to treat trauma patients.

MATERIALS AND METHODS

Post-operative radiographs of 46 patients, mean age 71, who underwent an uncemented, collarless, total hip replacement for trauma, were reviewed. The difference in distance from the calcar to the prosthesis tip between the immediate post operative radiograph and the subsequent follow-up radiograph was calculated and adjusted for magnification. The same procedure was performed on 36 age-matched patients, who underwent elective hip replacements for osteoarthritis. Hospital notes were reviewed to assess for complications and DEXA scans reviewed for trauma patients where available.

RESULTS

The mean femoral stem subsidence was significantly greater in the fracture cohort than in elective patients (p=0.001) with mean subsidence of 4.27 mm (range 0.02-22.05 mm) and 1.57 mm (range 0-5.5 mm), respectively. In the fracture cohort there were 4 revisions within 6 months of surgery, 1 for infection and 3 for femoral stem subsidence leading to dislocation. There were no revisions in the elective cohort.

DISCUSSION AND CONCLUSIONS

This study showed that collarless uncemented stems subsided significantly more when performed for fractures and had a high early revision rate. We recommend that uncemented collarless should not be used in trauma patients requiring total hip replacement.

A concise minimum eight year follow-up of proximally porous-coated tapered titanium femoral stem in primary total hip arthroplasty

PURPOSE

Our goal was to assess clinical and radiographic outcomes using a second-generation circumferentially proximally porous-coated titanium alloy stem at a minimum of eight years of follow-up.

METHODS

Ninety-one hips (80 patients) with Fibre Metal Taper (FMT, Zimmer Inc, Warsaw, IN, USA) femoral stems implanted between May 1998 and April 2002 were followed prospectively and re-evaluated at a minimum of eight years postoperatively. The median patient age was 56 (range 34-78) years, with 40 women and 40 men. Radiographic data and clinical follow-up using Harris Hip Score (HHS) and EuroQol (EQ)-5D outcome measures were evaluated.

RESULTS

Mean follow-up was 9.61 (range 8-12.3) years. At the time of the most recent follow-up, the mean HHS was 85.8 (range 46-100) points, mean EQ-5D Weighted Health State Index was 0.76 (range 0.05-1.00), and mean EQ-5D Visual Analogue Score was 80 (range 24-100). All stems were biologically stable, with all hips having osseous ingrowth. One stem was revised due to early periprosthetic fracture with stem subsidence. No hip had diaphyseal osteolysis.

CONCLUSIONS

To our knowledge, the data presented here represent the longest clinical follow-up of this second-generation cementless, proximally porous-coated femoral stem. The stems were found to perform well clinically and radiographically beyond the first five years previously reported in the literature. Patients had high levels of satisfaction and function, and osseous fixation occurred reliably without evidence of distal osteolysis.

Long-term follow-up results of a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels

PURPOSE

We evaluated the results of more than 10 years of follow-up of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels.

MATERIALS AND METHODS

One hundred five patients (129 hips) who underwent surgery between 1991 and 1996 for primary total hip arthroplasty using cementless straight distal fluted femoral stems were followed for more than 10 years. Ninety-four hips in 80 patients were available for clinical and radiologic analysis. The mean age at the time of surgery was 47 years, and the mean duration of follow-up was 14.3 years.

RESULTS

The mean Harris hip scores had improved from 58 points to 88 points at the time of the 10-year follow-up. Activity-related thigh pain was reported in nine hips (10%). At the last follow-up, 93 stems (99%) were biologically stable and one stem (1%) was revised because of loosening. No hip had distal diaphyseal osteolysis. Proximal femoral stress-shielding was reported in 86 hips (91%). We found no significant relationship between collar-calcar contact and thigh pain, stem fixation status, or stress-shielding. The cumulative survival of the femoral stem was 99% (95% confidence interval, 98-100%) after 10 years.

CONCLUSION

The long-term results of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels were satisfactory; however, the high rate of proximal stress-shielding and the minimal effect of the collar indicate the need for some changes in the stem design.

The stepwise introduction of innovation into orthopedic surgery: the next level of dilemmas

The optimum method for the appropriate introduction of innovative technologies into orthopedics is a vital but vexing issue. Compromises in the introduction process are driven by (a) the magnitude of the problem addressed (incidence and severity), (b) the advantages and risks of the proposed solution, and (c) the "universal dilemma," meaning the inherent "gap" between all the nonhuman supporting data and the unknowns of both efficacy and long-term safety in large human usage over many years. Drawing on the data generated and the actual decision tree used in the introduction of a new highly cross-linked polyethylene as a case study, this article illustrates these "subsequent dilemmas."

Cementless femoral fixation in total hip arthroplasty

A number of cementless femoral stems are associated with excellent long-term survivorship. Cementless designs differ from one another in terms of geometry and the means of obtaining initial fixation. Strict classification of stem designs is important in order to compare results among series. Loosening and thigh pain are less prevalent with modern stem designs. Stress-shielding is present in most cases, even with newer stem designs.

Cementless total hip replacement using second-generation components: a 12- to 16-year follow-up

We reviewed 123 second-generation uncemented total hip replacements performed on 115 patients by a single surgeon between 1993 and 1994. The acetabular component used in all cases was a fully porous-coated threaded hemispheric titanium shell (T-Tap ST) with a calcium ion stearate-free, isostatically compression-moulded polyethylene liner. The titanium femoral component used was a Taperloc with a reduced distal stem. No patient was lost to follow-up. Complete clinical and radiological follow-up was obtained for all 123 hips at a mean of 14 years (12 to 16). One femoral component was revised after a fracture, and three acetabular components for aseptic loosening. No additional femoral or acetabular components were judged loose by radiological criteria. Mild proximal femoral osteolysis was identified in two hips and minor acetabular osteolysis was present in four. The mean rate of penetration of the femoral head was 0.036 mm/year (0.000 to 0.227). These findings suggest that refinements in component design may be associated with excellent long-term fixation in cementless primary total hip replacement.

Fifteen-year to twenty-year results of cementless Harris-Galante porous femoral and Harris-Galante porous I and II acetabular components

This study examined long-term survivorship of primary total hip arthroplasty (THA) using cementless Harris-Galante porous femoral and Harris-Galante porous I or II acetabular components. Of 113 hips (101 patients) studied, 60 hips (53 patients) were available for follow-up at a mean of 17.2 years after surgery. A total of 10 hips had documented revision, and 2 hips had failed radiographically. The average Harris hip score was 82. Radiographically, 12 hips demonstrated eccentric wear, 8 had osteolysis, and 1 had a broken tine. The overall survival rate was 87.7%; the mean volumetric wear rate was 74.96 mm(3); and the mean polyethylene linear penetration rate was 0.153 mm/y, similar to that of well-cemented THA in other series. This long-term outcome for an early-generation cementless THA is promising and provides a standard by which to judge the newer generation of cementless implants.

Clinical and radiographic results for the Richards Modular Hip System prosthesis in total hip arthroplasty: average 10-year follow-up

The clinical results of total hip arthroplasty using the Richards Modular Hip System prosthesis were evaluated in 41 patients (44 joints). The mean Harris hip score improved from 42 points before surgery to 82 after 1 year, 85 at 5 years, and 79 at the final examination. The average polyethylene wear rate was 0.09 +/- 0.07 mm/y. Forty joints (90.9%) achieved press fit in either of the proximal or the distal stem portion, and only 4 joints (9.1%) failed to achieve press fit in both the proximal and distal stem portions. Although the 10-year survival of the stem was 94.5% and no revisions of the stem were performed, osteolysis was found at high frequency at a distal stem. The high incidence of osteolysis has been the limiting factor in the long-term success of Richards Modular Hip System. Achievement of good canal fill in both the proximal and distal stem portions did not contribute to the good long-term result of the stem.

High survival of uncemented proximally porous-coated titanium alloy femoral stems in osteoporotic bone

Because the initial fixation of an uncemented stem may be compromised in patients with osteoporotic bone (Class C, Dorr et al.), many surgeons prefer a cemented stem in this setting. We therefore determined the survival of an uncemented, proximally porous-coated, straight-stemmed, titanium alloy femoral component in patients with Class C bone when compared with Class A and B bone. We implanted proximally plasma-sprayed, straight-stemmed titanium alloy stems in 1994 patients (2321 hips). Of these, 625 hips (27%), 1569 hips (67%), and 127 hips (6%) were classified as Classes A, B, and C, respectively. Minimum followup was 2 years (mean, 5.9 years; range, 2-19.5 years). We identified no differences in Harris hip scores, pain, radiolucencies, or osteolysis among Classes A, B, and C hips. Stem survival at 5, 10, and 15 years for aseptic loosening (failure) was 100% in all patients with Class A bone; 99+% in all patients with Class B bone; and 100% in all patients with Class C bone. Initial stability and durable fixation can be achieved with the use of this uncemented stem in patients in whom a cemented stem traditionally has been preferred as a result of poor bone quality.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The John Charnley Award: Metal-on-metal hip resurfacing versus large-diameter head metal-on-metal total hip arthroplasty: a randomized clinical trial

Resurfacing arthroplasty has become an attractive option for young patients who want to maintain a high activity level. One recent study reported modestly increased activity levels for patients with resurfacing compared to standard total hip arthroplasty (THA). We conducted a prospective randomized clinical trial to compare clinical outcomes of resurfacing versus large-head metal-on-metal total hip arthroplasty. We randomized 107 patients deemed eligible for resurfacing arthroplasty to have either resurfacing or standard THA. Patients were assessed for quality-of-life outcomes using the PAT-5D index, WOMAC, SF-36, and UCLA activity score. The minimum followup was 0.8 years (mean, 1.1 years; range, 0.8-2.2 years). Of the 73 patients followed at least one year, both groups reported improvement in quality of life on all outcome measures. There was no difference in quality of life between the two arms in the study. Serum levels of cobalt and chromium were measured in a subset of 30 patients. In both groups cobalt and chromium was elevated compared to baseline. Patients receiving a large-head metal-on-metal total hip had elevated ion levels compared to the resurfacing arm of the study. At 1 year, the median serum cobalt increased 46-fold from baseline in patients in the large-head total hip group, while the median serum chromium increased 10-fold. At 1 year, serum cobalt was 10-fold higher and serum chromium 2.6-fold higher than in the resurfacing arm. Due to these excessively high metal ion levels, the authors recommend against further use of this particular large-head total hip arthroplasty.

LEVEL OF EVIDENCE

Level I, randomized clinical trial. See Guidelines for Authors for a complete description of levels of evidence.

Successful performance of the bi-metric uncemented femoral stem at a minimum follow-up of 13 years in young patients

We report the mean 15.2 year follow-up results for a porous coated version of the Bi-Metric (Biomet UK Ltd, Bridgend, UK) uncemented femoral stem in young patients. Sixty-four hips were implanted into 54 patients (mean age, 54.3 years) and followed up using the Hospital for Special Surgery score and regular radiographs. The first 13 patients had a TTAP-ST acetabulum (Biomet UK), the remainder receiving a Universal cup (Biomet UK). At 15.2 years, there were no stem failures or femoral revisions. The mean Hospital for Special Surgery score was 34.7 (20-40), and there was no evidence of stem loosening radiologically. There were 3 acetabular revisions and 3 liner changes at 10 years, with a further 5 cup revisions and 9 liner changes at final follow-up.

Second-generation uncemented stems: excellent 5-13-year results

INTRODUCTION

The purpose of this study was to prospectively evaluate the 5-13-year results of a cementless total hip arthroplasty with a special focus on the survivorship,occurrence of osteolysis, incidence of intraoperative femoral fractures, thigh pain, and cortical hypertrophy of the femoral stem. The femoral component used in this study was titanium fluted, slotted, symmetrical component that was prepared with intraoperative machining. The proximal third of the stem had hydroxyl-apatite coating and horizontal steps.

METHODS

The clinical and radiographical results of a consecutive series of 157 total hip arthroplasties (124 patients)with this stem were investigated. Minimum follow-up was 5 years. The average age of the patients at the time of surgery was 47 years. Three patients died and ten patients were lost to follow-up, leaving 142 hips for evaluation. The clinical result was evaluated on the basis of the Merled’Aubigné score, complications and thigh pain. A detailed radiographic analysis was performed at each follow-up visit. Kaplan–Meier survivorship analysis was performed to evaluate stem, cup, and bearing survivorship.

RESULTS

The mean follow-up was 8.5 years (range 5-13 years). The average Merle d’Aubigné score improved from 10.5 points preoperatively to 17.4 points postoperatively.The cumulative 10-year survival rate was 99% for the femoral component, 99% for the acetabular component,and 69% for the bearing. Thigh pain was identified in three patients (2%). There was no distal femoral osteolysis.Seventy-nine percent of all the hips had endosteal spot welds around the coated, proximal one-third of the prosthesis.51% had radio dense lines around the distal tip of the prosthesis,and 3% had cortical hypertrophy. One undersized stem and one cup were revised for aseptic loosening, and 25 bearings were exchanged.

CONCLUSIONS

Uncemented, machined, fluted titanium canal-filling femoral components achieve reliable fixation in this young patient population. They have a decreased incidence of activity-related thigh pain, lower rate of intraoperative femur fractures and cortical hypertrophy with comparable bone-ingrowth in comparison to other second generation uncemented femoral components described in literature. Bearing wear and the need for bearing exchange was the only limitation of these constructs.

The John Charnley Award: Metal-on-metal hip resurfacing versus large-diameter head metal-on-metal total hip arthroplasty: a randomized clinical trial

Resurfacing arthroplasty has become an attractive option for young patients who want to maintain a high activity level. One recent study reported modestly increased activity levels for patients with resurfacing compared to standard total hip arthroplasty (THA). We conducted a prospective randomized clinical trial to compare clinical outcomes of resurfacing versus large-head metal-on-metal total hip arthroplasty. We randomized 107 patients deemed eligible for resurfacing arthroplasty to have either resurfacing or standard THA. Patients were assessed for quality-of-life outcomes using the PAT-5D index, WOMAC, SF-36, and UCLA activity score. The minimum followup was 0.8 years (mean, 1.1 years; range, 0.8-2.2 years). Of the 73 patients followed at least one year, both groups reported improvement in quality of life on all outcome measures. There was no difference in quality of life between the two arms in the study. Serum levels of cobalt and chromium were measured in a subset of 30 patients. In both groups cobalt and chromium was elevated compared to baseline. Patients receiving a large-head metal-on-metal total hip had elevated ion levels compared to the resurfacing arm of the study. At 1 year, the median serum cobalt increased 46-fold from baseline in patients in the large-head total hip group, while the median serum chromium increased 10-fold. At 1 year, serum cobalt was 10-fold higher and serum chromium 2.6-fold higher than in the resurfacing arm. Due to these excessively high metal ion levels, the authors recommend against further use of this particular large-head total hip arthroplasty.

LEVEL OF EVIDENCE

Level I, randomized clinical trial. See Guidelines for Authors for a complete description of levels of evidence.

Uncemented grit-blasted straight tapered titanium stems in patients younger than fifty-five years of age. Fifteen to twenty-year results

BACKGROUND

Total hip arthroplasty without cement is frequently performed in young active patients, but only limited outcomes data are available after durations of follow-up of more than fifteen years.

METHODS

We retrospectively evaluated the clinical and radiographic results of a consecutive series of 154 total hip arthroplasties (in 141 patients) performed with an uncemented grit-blasted straight tapered titanium femoral stem combined with a threaded socket in patients under the age of fifty-five years. The median duration of follow-up was seventeen years. Clinical results were evaluated with use of the Harris hip score. The canal fill index was used as the criterion to determine the adequacy of stem sizing. Kaplan-Meier survivorship analysis was performed to predict long-term outcomes.

RESULTS

The stem was undersized, with a canal fill index of < or =80%, in forty-one hips (27%). Late aseptic loosening of the stem occurred in four femora, and the femoral component was undersized in all four. These four stems were stable for ten years and then underwent progressive subsidence, which was associated with pain. Five stems were revised because of a late postoperative periprosthetic fracture following trauma. Localized proximal femoral osteolysis was seen in seven hips without signs of loosening. Survivorship of the stem with revision for any reason as the end point was estimated to be 90% (95% confidence interval, 87% to 97%) at twenty years. Survivorship with aseptic loosening as the end point was estimated to be 95% (95% confidence interval, 91% to 99%) at twenty years. Sixty-seven (44%) of the threaded uncemented acetabular components were revised during the follow-up period.

CONCLUSIONS

After a minimum duration of follow-up of fifteen years, the survival of this type of femoral component is excellent in individuals younger than fifty-five years. The main mode of stem failure was a periprosthetic fracture due to trauma, or late aseptic loosening in a small percentage of the hips in which the femoral implant was undersized. The high rate of failure of the acetabular components was attributable to a poor design that is no longer in use.

Polyethylene wear and osteolysis with a new modular titanium acetabular component: results at 7 to 13 years

The first-generation and second-generation modular titanium fiber-metal acetabular components were notable for high rates of pelvic osteolysis and liner dislodgment. This is a prospective, consecutive study of 111 new modular titanium-fiber metal acetabular components with a novel polyethylene locking mechanism at a mean follow-up of 9.5 years (range, 7-13 years). The polyethylene was gamma-irradiated in air in 58 hips and gamma-irradiated in nitrogen in 54 hips. No acetabular component migrated, none were revised, and there was no liner dislodgment. Pelvic osteolysis was seen in only 2 hips. The mean linear wear rate was 0.085 mm/y (range, 0.001-0.3 mm/y). There was a significantly lower rate of wear with polyethylene liners sterilized by gamma-irradiation in nitrogen (P = .0001). The high rate of success and low rate of polyethylene wear and pelvic osteolysis at this length of follow-up may be related to the new design features of this modular acetabular component.

Computer-assisted technique to delineate osteolytic lesions around the femoral component in total hip arthroplasty

There are currently no ideal quantitative measures assessing osteolysis after total joint arthroplasty. This study reports a new approach for quantification of osteolytic lesions on radiographs of total hip arthroplasty with the hypothesis that computer-assisted lesion quantification improves analysis precision over currently used qualitative visual assessment and thus improves progression monitoring. Duplicate exposure sets of anterior-posterior and frog-leg view radiographs of 15 volunteer total hip arthroplasty patients with radiographically evident periprosthetic lucencies were used. Two independent readers delineated the lesions using on-screen digital marker tools. Based on duplicate readings of the first exposure set only, intraoperator precision had a coefficient of variation (CV) from 1.5% to 3.4%, whereas interoperator precision CV ranged from 3.2% to 4.6%. The reproducibility of the x-ray technique as assessed by single readings of both sets of x-rays was CV 3.2% to 4.8%. The new technique compares favorably to precision of qualitative visual assessment and permits more accurate detection and quantitation of osteolytic lesions.

Acetabular reinforcement ring in primary total hip arthroplasty: a minimum 10-year follow-up

INTRODUCTION

We report the results of a titanium acetabular reinforcement ring with a hook (ARRH) in primary total hip arthroplasty (THA), which was introduced in 1987 and continues to be used routinely in our center. The favorable results of this device in arthroplasty for developmental dysplasia and difficult revisions motivated its use in primary THA. With this implant only minimal acetabular reaming is necessary, anatomic positioning is achieved by placing the hook around the teardrop and a homogenous base for cementing the polyethylene cup is provided.

MATERIALS AND METHODS

Between April 1987 and December 1991, 241 THAs with insertion of an ARRH were performed in 178 unselected, consecutive patients (average age 58 years; range 30-84 years) with a secondary osteoarthrosis in 41% of the cases.

RESULTS

At the time of the latest follow-up, 33 patients (39 hips) had died and 17 cases had been lost to follow-up. The median follow-up was 122 months with a minimum of 10 years. Eight hips had been revised, leaving 177 hips in 120 living patients without revision. Six cups were revised because of aseptic loosening. Two hips were revised for sepsis. The mean Merle d'Aubigné score for the remaining hips was 16 (range 7-18) at the latest follow-up. For aseptic loosening, the probability of survival of the cup was 0.97 (95% confidence interval, 0.94-0.99). However, analysis of radiographs implied loosening in seven other cups without clinical symptoms.

CONCLUSIONS

The results of primary THA using an acetabular reinforcement ring parallel the excellent results of these implants often observed in difficult primary and revision arthroplasty at a minimum of 10 years. Survivorship is comparable to modern cementless implants. Medial migration that occurs with loosening of the acetabular component seems to be prevented with this implant. Radiographic loosening signs can exist without clinical symptoms.

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.

Primary total hip arthroplasty with an uncemented femoral component: two- to seven-year results

This prospective study reports the midterm outcome of total hip arthroplasty performed in a consecutive series of patients using a tapered uncemented femoral component. The cohort consists of 631 patients (700 hips). The clinical records and the routine serial radiographs of these patients were monitored closely over a 5-year period. Follow-up averaged 4.35 years. There was a significant improvement in functional outcome of these patients as measured by Harris hip score and short-form 36.There were 4 revisions for aseptic loosening of the femoral component in this series, accounting for an overall survivorship of 99.4%. The study confirms that the midterm outcome of this stem is excellent, with a low revision rate.

Femoral osteolysis following total hip replacement

Total hip replacement represents the most significant advance in orthopaedic surgery in the 20th century. Periprosthetic osteolysis remains the most significant long-term complication with total hip replacement. It has been reported with all materials and prosthetic devices in use or that have been used to date. This paper reviews the current thinking on the aetiology, pathogenesis, management and future treatment options for osteolysis.

Outcome of an acetabular design with hydroxyapatite coating on a rough substrate

Outcomes of hydroxyapatite-coated cups have not been as consistently successful as outcomes of hydroxyapatite-coated stems; therefore, we studied a newer generation acetabular design with a plasma-sprayed hydroxyapatite coating on an arc-deposited rough titanium substrate. Our objective was to determine whether clinical and radiographic outcomes would be better than reported for earlier-generation designs. Ninety consecutive hips in 85 patients implanted with this design were followed up prospectively for 2 to 5 years after surgery. Hip scores improved from a preoperative mean of 59 (+/- 12) to final followup mean of 91 (+/- 12). One hip was revised for recurrent dislocation. No hips were revised for aseptic loosening. No cup had complete continuous radiolucent lines. Incomplete lucent lines were noted on early postoperative radiographs. With followup, radiolucent line length decreased by a mean 32% and radiolucent line density increased by 9%. Mean polyethylene linear and volumetric head penetration rates were 0.17 (+/- 0.16) mm/year and 73 (+/- 70) mm/year, respectively. Head penetration rates were higher in men. No other factor (age, body weight, cup abduction, or anteversion angle) correlated with head penetration rate. Our study presents encouraging short-term results. Improvement in radiolucent lines suggests a beneficial effect of hydroxyapatite coating on osseointegration of the cup.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Five- to fifteen-year clinical results and the radiographic evaluation of acetabular changes after bipolar hip arthroplasty for femoral head osteonecrosis

We have studied 36 hips in 30 patients with osteonecrosis of the femoral head who were treated with bipolar hip arthroplasty. Follow-up period was 5 to 15 (average 7.7) years. Five hips were revised. Hips were divided into 2 groups. Sixteen hips with Ficat stage II or III osteonecrosis were assigned into group I, and 15 hips with Ficat stage IV osteonecrosis were assigned into group II. There was no statistical difference between the clinical results of the 2 groups (P = .74). Radiographically, there was minimal migration in group I. There was a statistical significance in superior migration between subgroups with and without osteolysis in group II (P < .01). We emphasize that bipolar hip arthroplasty is indicated for Ficat stage II or III in osteonecrosis of the femoral head.

Zementfreie Hüftschäfte

Optimal fixation of cementless stems is a precondition for long-lasting stability. Thus, anchorage, stabilizers, material and surface are of essential importance. To achieve primary stability, good rotational, tilting and axial stability is necessary. Stabilizers such as fins and ribs optimize stability. The CCD-angle and length of neck-axis determine the offset (laterality), leg-length and center of rotation. The stem, is responsible for the fixation of the prosthesis and for transmitting forces to the bone. The types of fixation are epiphyseal (the femoral head is covered by a cup prosthesis), metaphyseal and meta-diaphyseal (with straight or anatomically shaped monoblock-prostheses of different lengths, modular and custom-made prostheses) and diaphyseal (using predominantly modular systems). Titanium alloys are the predominate material for cementless stems. The surfaces are generally corundum-blasted or plasma sprayed. For metaphyseal and meta-diaphyseal stems, survival rates from 95 to 98% have been reached after 15 years. Diaphyseal-fixed stems have mid-term survival-rates of 92-99%.

Excellent results from proximally HA-coated femoral stems with a minimum of 6 years follow-up: a prospective evaluation of 100 patients

BACKGROUND

There have been few reports on the mid- and long-term follow-up results of the proximally HA-coated femoral stem. We evaluated this type of stem prospectively, with 6-12 years of follow-up.

METHODS

The survival rate, Harris hip score and radiographic features of 106 hips in 100 consecutive patients were evaluated. The mean age at operation was 51 years (SD 8.2).

RESULTS

The mean Harris hip score at the time of the latest follow-up was 95 points. Spot welds occurred in 95% of the patients and were first observed at a mean follow-up of 1.4 years in one or more of the Gruen regions, corresponding to the coated part of the femoral stem. A higher grade of stress shielding correlated with a less favorable Harris hip score and pain subscore. According to the criteria of Engh, all stems were graded as stable and durable bone-ingrown. No femoral component was revised.

INTERPRETATION

At an average follow-up of 8 years, this proximally HA-coated femoral component showed favorable clinical and radiological outcome and excellent survivorship.

A quantitative and qualitative analysis of bone remodelling around custom uncemented femoral stems: a five-year DEXA follow-up

BACKGROUND

After total hip replacement bone remodelling is determinant for the implant survival. This study asked whether the immediate postoperative amount and distribution of bone can predict the changes in bone amount and distribution after five years in the case of younger patients with custom uncemented implant.

METHODS

We investigated 17 hips with a mean follow-up of 5.1 years. The average patient age at follow-up was 48.5 years. We used immediate postoperative and five-year dual energy X-ray absorptiometry measurements of bone mineral content, density, and projected bone area in seven local zones forming a partition of the upper femur. A correlation was sought between the preoperative variables and the five-year variation. Qualitative bone remodelling was analysed considering each local zone in a density-area plane. Based on geometrical considerations, we introduced an index of structural remodelling, which expresses the preponderance of internal remodelling against external modelling.

FINDINGS

The bone mineral content at operation correlated significantly with its relative decrease locally laterally mid-proximally and medially (P<0.01), distally, and globally for the femur (P<0.05). For the bone mineral density, the correlation was significant distally, medially and globally (P<0.05). The bone projected area shows only significant correlation laterally mid-proximally (P<0.01). The index of structural remodelling was significantly positive (P<0.01) in all local zones and was independent of the initial bone amount and structure (P>0.1).

INTERPRETATION

High bone mineral content at operation correlates significantly with periprosthetic bone loss after five years in younger patients with cementless custom femoral implant. Independently of the net bone mineral content balance, external modelling is stronger than internal remodelling in all local zones.

Uncemented Harris-Galante total hip arthroplasty in patients with osteonecrosis of the femoral head. A 10-16-year follow-up study

BACKGROUND

There have only been a few reports regarding the long-term results of uncemented THAs in patients with osteonecrosis.

PATIENTS AND METHODS

We evaluated the long-term results of 65 consecutive uncemented total hip arthroplasties (Harris-Galante type I prostheses) in 54 men (59 hips) and 5 women (6 hips) with osteonecrosis of the femoral head. The mean age was 53 (33-64) years. The mean duration of follow-up was 12.5 (10-16) years.

RESULTS

9 femoral stems and 3 acetabular metal shells were revised. 2 polyethylene liners were changed due to excessive wear. A girdlestone procedure was done in 2 patients (2 hips) due to delayed deep infection. The mean polyethylene wear was 0.14 mm per year. 3 non-revised hips had pelvic osteolysis and 18 had femoral osteolysis. The 15-year survival rates, using failure defined as the removal of any component for any reason, were 85 (95% CI; 79-91)% for the acetabular and 80 (74-86)% for the femoral component and 70 (63-77)% for any of the components.

INTERPRETATION

The first generation of the HGP design was frequently associated with pain, unstable fixation, and osteolysis. Excessive wear was frequent. The cup showed better durability than the stem.

Biologic fixation and bone ingrowth

Total hip arthroplasty has provided thousands of patients with pain relief and has improved their quality of life. Advances in orthopaedic surgical techniques and implant biomaterials now allow predictable surgical results in most patients. Despite the overwhelming success of this surgical procedure, the debate continues surrounding the optimal choice of implants. Femoral and acetabular implants with varying geometries and fixation methods are currently available. Acrylic bone cement has been used extensively in the past for acetabular and femoral fixation. This mode of component fixation currently remains the technique used most frequently throughout Europe and has shown excellent long-term results. Problems inherent with acrylic bone cement, however, have encouraged other surgeons to use alternative surfaces to allow biologic fixation.

A review of current cross-linked polyethylenes used in total joint arthroplasty

Major improvements have been made in new polyethylenes in regards to wear resistance and oxidation resistance. The background for and explanation of these improvements are presented in this study. The various manufacturing processes are described along with the possible features that the differences in manufacturing processes may have on wear, rate of particle generation, oxidation and mechanical properties. The role of some of the new polyethylenes in permitting the use of larger-diameter heads and the advantages of large-head diameters are discussed. Some of the advantages of metal-on-polyethylene versus hard-on-hard bearings also are described.

Conquest of a worldwide human disease: particle-induced periprosthetic osteolysis

It is rare in the long history of human disease to encounter a completely unique disease. In the 21st century, when it does occur, the disease commonly is man-made, as is true for periprosthetic osteolysis. However, it also is rare to unravel the mysteries of a biologic process as complex as periprosthetic osteolysis in slightly longer than one generation and even less common to create the means for the worldwide prevention of an entire disease. Such is the story of periprosthetic osteolysis. The adventure from the iatrogenic creation of the disease to the identification of its pathology, to the understanding of its molecular biology and, subsequently, to its prevention, during a period of four decades, is a fascinating story of medical detective work.

Primary total hip arthroplasty with a proximally porous-coated femoral stem

BACKGROUND

The use of cementless, proximally porous-coated femoral stems for total hip arthroplasty has increased in popularity. The purpose of the present report was to examine the five to ten-year results associated with the use of a so-called second-generation circumferentially proximally porous-coated titanium-alloy stem.

METHODS

Between 1991 and 1994, 123 Harris-Galante Multilock femoral stems were implanted in 101 patients. The average age of the patients at the time of surgery was 53.8 years. The patients were followed prospectively and were reevaluated at a minimum of five years postoperatively. No patient was lost to follow-up. Twenty-five patients (thirty hips) were interviewed by telephone, and four patients (five hips) died during the study period because of problems that were unrelated to the operation. The remaining seventy-two patients (eighty-eight hips) had a minimum of five years of clinical and radiographic follow-up.

RESULTS

The average duration of follow-up was seventy-eight months. At the time of the most recent follow-up, the average Harris Hip Score was 95 points. Eighty-seven (99%) of eighty-eight stems were biologically stable, with eighty-four hips (95%) having osseous ingrowth and three hips (3%) having stable fibrous fixation. One stem was revised because of loosening. Thirty-three hips (38%) had minimal proximal osteolysis, and no hip had diaphyseal osteolysis. Seventy-two hips (82%) had some degree of stress-shielding in the proximal metaphysis, but only two hips had cortical resorption. None of these patients required additional surgery, and all reported a satisfactory outcome.

CONCLUSIONS

Given the young age and high activity level of these patients, this stem fared well: the levels of patient function and satisfaction were high, the rates of loosening and revision were very low, and distal osteolysis did not occur. Osseous fixation occurred reliably. Proximal stress-shielding was seen but did not seem to be clinically important.

Primary total hip arthroplasty with an uncemented femoral component: a long-term study of the Taperloc stem

The purpose of the current study was to evaluate the long-term result of a tapered, uncemented femoral component. We retrospectively reviewed the clinical and radiographic records of 121 patients (129 hips) who underwent primary total hip arthroplasty with the use of the Taperloc uncemented stem. Follow-up averaged 11 years (range, 6-15 years). The mean Harris Hip Score at the latest follow-up was 92.1. Thigh pain was reported in 5 patients (3.6%). One stem was revised at 6 years because of severe proximal femoral osteolysis. There was no evidence of radiographic subsidence or loosening around any stems. The overall medium- to long-term outcome of the Taperloc stem is excellent, with a low revision rate and high patient satisfaction.

Minimum ten-year follow-up of a straight-stemmed, plasma-sprayed, titanium-alloy, uncemented femoral component in primary total hip arthroplasty

BACKGROUND

The long-term results of total hip arthroplasty without cement have been reported only rarely. The purpose of the present study was to evaluate the minimum ten-year results of primary total hip arthroplasty performed with use of a proximally porous-coated, plasma-sprayed, straight-stemmed, titanium-alloy femoral component.

METHODS

The clinical and radiographic results of a consecutive series of 105 total hip replacements in ninety-five patients were reviewed ten to twelve years postoperatively. The diagnosis was osteoarthritis for seventy-seven hips (73%). The clinical result was evaluated on the basis of the Harris hip score, complications, and thigh pain. A detailed radiographic analysis was performed at each follow-up visit. Kaplan-Meier analysis was performed to evaluate the survival of the femoral component.

RESULTS

The average Harris hip score improved from 46 points preoperatively to 92 points postoperatively. The average pain score at the time of the most recent follow-up was 42 points, with eighty-three hips (79%) rated as pain-free. Thigh pain was identified in only two patients. All radiolucent lines were seen around the tip of the stem. All hips had some degree of femoral remodeling consistent with osseous ingrowth. No femoral component was revised, and no femoral component had evidence of loosening. Eight acetabular components were revised because of loosening and wear, and one was revised because of recurrent dislocation. One focal femoral osteolytic lesion was seen.

CONCLUSIONS

This femoral component afforded durable fixation at ten to twelve years after primary total hip arthroplasty.

LEVEL OF EVIDENCE

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

The uncemented Bi-Contact total hip arthroplasty

We reviewed a consecutive series of 153 uncemented Bi-Contact (Aesculap, Tuttlingen, Germany) total hip arthroplasties (THAs) in 138 patients who had been followed for at least 5 years (mean, 6.8 years; range, 5-9 years). The Bi-Contact uncemented THA consists of a straight femoral stem made of titanium alloy. The proximal portion of the stem is titanium plasma-sprayed. The cup is press-fit with or without hydroxyapatite coating with a facility for anchoring screws with a snap-fit polyethylene liner. The mean age of the patients was 70.8 years (range, 41-94 years). The mean preoperative Harris hip score of 41 (range, 20-80) improved postoperatively to a mean of 92 (range, 56-96). Three acetabular cups were revised for aseptic loosening, and 1 cup was revised for recurrent dislocation. To date, none of the stems have been revised for aseptic loosening. Radiographic evaluation of the remaining 149 hips revealed that the acetabular cup was stable in 146 hips and possibly unstable in the remaining 3 cases with nonprogressive osteolysis behind the cup. None of the stems showed any evidence of instability. Using the recommendation of revision as the endpoint, the cumulative survival for the prosthesis was 97.3% at a mean follow-up of 6.8 years (95% confidence interval, 95.9-99.4), with stem survival of 100%. In the medium-term, these results are comparable to cemented primary THA and justify the continued use of this prosthesis.

Adeno-associated virus-mediated osteoprotegerin gene transfer protects against particulate polyethylene-induced osteolysis in a murine model

OBJECTIVE

Osteoprotegerin (OPG), a natural negative regulator of osteoclastogenesis and bone resorption, may be a potential therapeutic agent for treatment of osteolysis-associated prosthetic joint loosening. Using an in vivo adeno-associated virus (AAV)-mediated gene transfer technique, this study was designed to evaluate the protective effects of OPG transgene against orthopedic wear debris-induced bone loss in a murine model of osteolysis.

METHODS

Bone tissue was implanted into established pouches on BALB/c mice, followed by the introduction of ultra-high-molecular-weight polyethylene (UHMWPE) particles to provoke inflammation and osteolysis. The viruses encoding human OPG gene (rAAV-hOPG) or beta-galactosidase marker gene (rAAV-LacZ) were injected into the air pouches, and the tissue was harvested 7 days after viral infection for histologic and molecular analyses.

RESULTS

Successful transgene expression was confirmed by the detection of OPG by enzyme-linked immunosorbent assay and positive X-Gal staining of pouch tissue (LacZ). Real-time polymerase chain reaction indicated significant diminishment of messenger RNA expression of osteoclast markers in OPG-transduced pouches compared with rAAV-LacZ-transduced pouches. The transduction and expression of OPG also markedly decreased the gene copies of the biologic receptor activator of nuclear factor kappaB. The expression of OPG in the bone-implanted pouch reduced bone calcium release by a mean of 39% compared with the calcium release in the other 2 groups. Computerized image analysis revealed that expression of OPG significantly protected against bone collagen loss.

CONCLUSION

OPG gene transfer mediated by rAAV effectively protects against particulate polyethylene-induced bone resorption in this experimental model. Data suggest that gene transfer using rAAV-OPG may be a feasible and effective therapeutic candidate to treat or prevent wear debris-associated osteolysis and aseptic loosening.

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).

Primary total hip arthroplasty using a grit-blasted, press-fit femoral prosthesis.Long-term results with survivorship analysis

BACKGROUND

This report presents the initial experience with the use of a grit-blasted, press-fit femoral prosthesis.

METHODS

The first 300 consecutive primary total hip arthroplasty procedures using a collarless, three-dimensional tapered, straight, titanium alloy stem with a grit-blasted surface (performed in 299 patients) were evaluated with independent clinical and radiographic follow-up examinations up to sixteen years. Eight different types of acetabular components, including a cementless all-polyethylene socket in 80 percent of the cases, were used. Radiographic evaluation, performed by an independent observer using a zonal analysis method, included assessment of component migration, Enghs implant-bone femoral fixation score, implant-bone demarcations, and periprosthetic osteolysis. The average duration of long-term radiographic follow-up was 12.6 years (range; 10 to 16 years).

RESULTS

At last examination only five hips were lost to follow-up and 69 patients were deceased. The overall mechanical failure rate (i.e. unstable with or without revision) of the femoral component was 2 percent. The femoral revision rate was 7 percent (two hips for aseptic loosening, five hips for septic loosening, and twelve hips with osseointegrated stems for severe progressive femoral osteolysis) and the acetabular revision rate was 27 percent (revised for either socket migration or progressive peri-acetabular osteolysis or both). Survivorship, based on any revision (femoral or acetabular) was 89 percent at ten years and 62 percent at fourteen years; survivorship of the femoral component was 95 percent at ten years and 90 percent at fourteen years. The incidence of femoral periprosthetic osteolysis, by radiographic examination at ten years or more was 47 percent, including 12 hips (5 percent) with distal endosteal osteolysis. Femoral implant-bone fixation was stable, bone-ongrowth in 97 percent; stable, fibrous-fixation in 1 percent, and unstable, fibrous-fixation in 2 percent of the cases.

CONCLUSIONS

The grit-blasted, press-fit, collarless, tapered femoral component continued to per-form well clinically and radiographically up to sixteen years of follow-up despite the challenging environment of periprosthetic osteolysis associated with the acetabular component design. The high incidence of failure among the cementless all-polyethylene sockets was not unexpected and the use of this acetabular implant was discontinued in 1985. While considered a "first-generation" cementless stem, this implant is still in use virtually without design modifications. This study demonstrates the durability of the results of the grit-blasted femoral component and indicates that such an implant offers a viable alternative for fixation without bone cement. (Hip International 2002; 2: 55-72).