Primary total-hip arthroplasty with the autophor 900-s fully porous coated stem in young patients seven to seventeen years of follow-up

Primary total hip arthroplasty with a fully porous-coated uncemented stem: up to twenty-eight years. Retrospective cohort study

PURPOSE

The use of cementless prosthesis has increased in the last 30 years with the aim of improving the long-term results of total hip arthroplasties in young and active patients. Encouraging results have recently been reported for cementless titanium and cobalt chromium stems. However, there are few studies with long-term follow-up, and the majority have analysed several models of uncemented stems due to their modifications over the years. Therefore, the aim was to assess the long-term survival rate of the Mittelmeier Mark III or Autophor 900-S stem.

METHODS

A retrospective cohort study of both gender patients under 70 years old with at least one implanted Mittelmeier Mark III uncemented stem was performed. Survival rate was defined as the proportion of stems that did not need a surgical revision from any cause. Clinical status was evaluated using the Merle d'Aubigne scale modified by Matta (excellent/good/fair/poor).

RESULTS

Between 1990 and 1999, 73 stems were implanted. The mean (SD) age at surgical time was 49.3 (9.9) years, and the median (range) of follow-up was 22 (1-28) years. The overall survival rate was 93% (68/73, 95%CI: 85-97%). The stem revisions were due to stem breakage (n = 2), to aseptic loosening (n = 2) and to septic loosening (n = 1). Clinical results were: excellent 84%, good 15% and fair 1.5%.

CONCLUSIONS

The Mittelmeier Mark III stem had an excellent survival rate with a stable long-term fixation and excellent clinical outcomes.

Long-Term Outcomes of Ultra-Short Metaphyseal-Fitting Anatomic Cementless Femoral Stem in Total Hip Arthroplasty With Ceramic-on-Ceramic Articulation for Young Patients

BACKGROUND

The aim of this study is to assess the long-term outcomes of this specific stem in patients younger than 50 years old, with regard to clinical and radiographic outcomes, survivorship, and complication rate.

METHODS

Two hundred thirty-nine consecutive series of patients (324 hips) who were younger than 50 years old at the time of surgery were enrolled in the study. Osteonecrosis (50%) and dysplastic hip (34%) were most common diagnoses. Patients were informed to use crutches or walker for 4 weeks to protect the femoral component against rotational stress. The mean follow-up was 15.6 years (range 14-17).

RESULTS

At the latest follow-up, the mean Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index score, and University of California, Los Angeles activity score were 93 points, 13 points, and 7 points, respectively. Three patients (1.3%) had moderate thigh pain. All of the acetabular components and 321 (99%) femoral stems were solidly fixed at the time of the latest follow-up. Three stems (0.9%) were revised for aseptic loosening. Two hips (0.6%) had a dislocation and 2 hips (0.6%) had a periprosthetic fracture. Ceramic fracture or osteolysis was not found in any hip at the time of the final follow-up. Survival rate of the femoral component was 99.1% (95% confidence interval 94-100) and that of the acetabular component was 100% (95% confidence interval 94-100) at 15.6 years.

CONCLUSION

In this series, THA using an ultra-short metaphyseal-fitting anatomic cementless femoral stem provided excellent long-term clinical and radiographic results in patients younger than 50 years old. Furthermore, our initial theoretical concerns about early aseptic loosening due to the absence of distal stem fixation were not justified.

A 30-Year Single-center Experience of Cementless Total Hip Arthroplasty With Spongy Metal Structured Implants: A Follow-up of a Previous Report

BACKGROUND/AIM

The aim of this study was to analyze survivorship and functional outcome of cementless spongy metal structured total hip arthroplasty (THA) after ultra-long-term follow-up.

PATIENTS AND METHODS

A total of 100 THAs in patients under 65 years at initial surgery were performed between 1985 and 1989 at our Department. Twenty patients (23 hips) were available for final follow-up. Implant survivorship and functional results (Merle d'Aubigné, SF-12) were assessed.

RESULTS

At a mean follow-up of 30 years (range=27.7-31.7 years), the overall stem survival rate was 82.6% (19/23 stems) and the overall cup survival rate was 52.2% (12/23 cups). Revision surgeries were performed for aseptic loosening in all cases. Functional evaluation revealed good to excellent results in 16 patients (80%) Conclusion: Spongy metal structured cementless THA provides remarkable survivorship and excellent functional results even after ultra-long-term follow-up. Further research regarding modern implants, bearing surfaces etc. is required to assess survivorship and clinical outcomes of different implant designs.

Breakage of metal hip arthroplasty components: Retrieval and structural analysis

BACKGROUND

Breakage of joint arthroplasty components are rare, yet during an implant retrieval program we found several cases.

OBJECTIVE

In this study we examined the components to determine the causes and mechanisms of breakage of these implants.

METHODS

From our collection of 849 retrievals we selected 682 cases with metal parts (503 hip, 79 knee arthroplasties) and identified fractured components: seven hip resurfacing implants, five total hip replacement stems, one monopolar femoral head, and one modular revision femoral stem from. Implants were examined using optical and scanning electron microscopy; metallographic sections were prepared and samples of periprosthetic tissues underwent microscopic examination.

RESULTS

In the resurfacing components breakage occurred in small stems placed in the femoral neck due to necrosis of femoral heads, with no metal flaws detected. Fatigue breakage of femoral stems was caused by presence of material flaws in the CoCrMo alloy, and corrosion. The monopolar head failed in fatigue fracture mechanism, breakage was initiated in an undercut near the taper connection for femoral component. The modular stem from Ti alloy sustained fatigue fracture induced by corrosion caused by debris from previously revised stem; no material flaws were detected in this sample. In most cases periprosthetic tissues had a morphology typical for aseptic loosening.

CONCLUSIONS

In our series failure was caused by material flaws, presence of stress raisers and localized corrosion. Our findings indicate that sharp edges and other features which can act as stress raisers should be avoided in newly designed implants. Corrosion induced fracture of the modular Ti stem indicates the need for a detailed debridement of periprosthetic tissues during revision arthroplasties.

Long-term results and bone remodeling after THA with a short, metaphyseal-fitting anatomic cementless stem

BACKGROUND

Long-term results of standard total hip arthroplasty (THA) in young patients were not optimal. There are a number of reported disadvantages to longer cementless stems in THA including thigh pain and proximal stress shielding. However, it is unknown whether a short, metaphyseal-fitting anatomic stem without diaphyseal fixation, which represents a possible alternative, will maintain fixation over the longer term.

QUESTION/PURPOSES

We therefore evaluated long-term (1) clinical results using validated scoring instruments; (2) osseointegration and bone remodeling; (3) complications; and (4) rates of revision and osteolysis in patients younger than 65 years who underwent THA with a short, metaphyseal-fitting anatomic cementless stem.

METHODS

We reviewed 500 patients (630 hips) younger than 65 years (mean age at surgery, 52.7 years) who underwent THA with the Immediate Postoperative Stability stem (IPS; DePuy, Leeds, UK) by one surgeon (Y-HK) from January 1995 to March 2002. Demographic data, Harris hip score, WOMAC score, UCLA activity score, and radiographic data were recorded. All patients underwent dual-energy x-ray absorptiometry scanning of the acetabulum and proximal femur at 2 weeks after the operation and at final followup to determine stress shielding. Thigh pain was specifically investigated and scored by patients on a visual analog scale. Other complications were recorded. We determined component survival rates at 15 years using revision and aseptic loosening as end points. Minimum followup was 11 years (mean, 15.8 years; range, 11-18 years).

RESULTS

The clinical and functional results improved significantly for the Harris hip score, WOMAC, and UCLA activity scores (p < 0.001). At latest followup, mean Harris hip, WOMAC, and UCLA activity scores were 94 (range, 71-100), 15 (range, 5-29), and 7.9 (range, 6-9) points, respectively. All hips had osseous integration of the acetabular and femoral components. No patients had thigh pain. Four hips (0.6%) had deep infection and four (0.6%) had a recurrent dislocation. No patients had Grade 3 stress shielding. Fifteen-year survival rates were 98.7% (95% confidence interval [CI], 0.95-1.00) for the acetabular component and 99.4% (95% CI, 0.97-1.00) for the femoral component with revision as the end point and 100% (95% CI, 0.98-1.00) for both components with aseptic loosening as the end point.

CONCLUSIONS

The short, metaphyseal-fitting anatomic cementless femoral stem provided stable fixation without relying on diaphyseal fixation in younger patients, suggesting metaphyseal fitting alone is sufficient in young patients who have good bone quality. Because we observed no thigh pain and little stress shielding in our patients, modifying the distal stem design as is done with this implant might be advantageous, but this would need to be determined in future comparative studies.

LEVEL OF EVIDENCE

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

Cementless metaphyseal fitting anatomic total hip arthroplasty with a ceramic-on-ceramic bearing in patients thirty years of age or younger

BACKGROUND

The number of midterm or long-term studies on the current generation of cementless total hip replacements with alumina-on-alumina ceramic bearings in patients younger than thirty years of age is limited. The purpose of this study was to evaluate the midterm results of the cementless metaphyseal fitting anatomic total hip prosthesis in patients younger than thirty years of age, with a particular emphasis on the prevalence of thigh pain, resorption of bone due to stress-shielding of the proximal part of the femur, aseptic loosening, and osteolysis.

METHODS

We reviewed the cases of ninety-six patients (127 hips) who had a cementless total hip arthroplasty when they were thirty years or younger at the time of surgery. All surgical procedures were performed by a single surgeon. The most common diagnoses were osteonecrosis (54.3%) and developmental dysplasia of the hip (20.5%). Demographic data, the Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and University of California, Los Angeles (UCLA) activity scores were recorded. Radiographic evaluation was used to evaluate implant fixation and osteolysis. The minimum follow-up interval was ten years (mean, 14.6 years; range, ten to sixteen years).

RESULTS

The mean preoperative Harris hip score, WOMAC score, and UCLA activity score were 41 points, 66 points, and 3 points, respectively. At the time of final follow-up, the mean Harris hip score, WOMAC score, and UCLA activity score were 95 points, 16 points, and 8 points, respectively. No patient had thigh pain after one year postoperatively. All of the femoral stems and all but one of the acetabular components were well-fixed at the time of final follow-up. No hip exhibited squeaking, ceramic fracture, loosening, or osteolysis at the time of the final follow-up.

CONCLUSIONS

These results in patients thirty years of age or younger suggest that the cementless metaphyseal fitting anatomic total hip prosthesis provides outstanding midterm fixation and substantial pain relief well into the second decade postoperatively. Moreover, the alumina-on-alumina ceramic bearing provides a high rate of survivorship without osteolysis.

The effect of femoral stem length on duration of hospital stay

Length of post-operative stay is an important factor in improving cost-effectiveness of total hip arthroplasty (THA). Short stem femoral components may reduce soft tissue and bone damage, permitting earlier mobilization and earlier safe discharge from hospital. This study compares the length of stay of patients undergoing THA using a short stem femoral component compared to an age matched group undergoing standard THA. The mean age in the standard stem group was 52.7 years and 50.4 years in the short femoral stem group (p=0.57). Total theatre time, blood loss and post-operative Oxford hip scores in the groups were not statistically different (p=0.11, p=0.91, p=0.16). Mean post-operative stay for the short stem group was shorter (3 vs 5 days, p=0.010), resulting in 10% cost saving per patient episode.

Primary cementless total hip arthroplasty with an alumina ceramic-on-ceramic bearing: results after a minimum of twenty years of follow-up

BACKGROUND

The biological problems related to wear debris after total hip arthroplasty have stimulated renewed interest in alternatives to metal-on-polyethylene bearing surfaces.

METHODS

We retrospectively evaluated the clinical and radiographic results of 100 patients who had undergone a total of 109 primary total hip arthroplasties with a cementless alumina ceramic-on-ceramic prosthesis between January 1985 and December 1989. The mean age of the patients at the time of the index arthroplasty was forty-six years. Clinical evaluation was performed with use of the Charnley modification of the Merle d'Aubigné-Postel scale. Seventy-eight patients who had had a total of eighty-five arthroplasties were available for follow-up evaluation at an average of 20.8 years. The patients' average age at the time of the latest follow-up was 66.8 years.

RESULTS

Six hips (six acetabular cups and one femoral stem) in six patients underwent revision. Aseptic loosening of the cup combined with focal osteolysis was the cause of all six revisions. In one patient, the stem was also revised because of aseptic loosening. At the time of final follow-up, the result was excellent (according to the Merle d'Aubigné-Postel scale) in 68% of the hips, good in 19%, fair in 9%, and poor in 4%. The mean Merle d'Aubigné-Postel score improved from 7.9 points preoperatively to 16.9 points postoperatively (p < 0.001). The cumulative rate of survival of the prostheses was 84.4% at 20.8 years.

CONCLUSIONS

The results of these cementless ceramic-on-ceramic total hip arthroplasties continued to be satisfactory at a minimum of twenty years postoperatively. The improved design of contemporary prostheses and the new generation of ceramic-on-ceramic bearing surfaces may lead to even better long-term results.

A stature-specific concept for uncemented, primary total hip arthroplasty

BACKGROUND AND PURPOSE

Variations in hip anatomy limit the femoral canal fit of standard uncemented hip stems. In addition, there are still issues with leg length discrepancy and offset reconstruction, potentially resulting in impingement, dislocation, and wear. Modular stems with different shapes for femoral canal fit and multiple neck options may improve the outcome and reduce complications.

PATIENTS AND METHODS

173 patients (190 hips) received an uncemented THA with 1 of 2 different stem shapes for canal fit and a modular neck for stature-specific hip reconstruction. Median follow-up time was 9 (7-13) years. During the follow-up period, 20 patients died (22 hips) and 12 patients (13 hips) were lost to follow-up. 155 hips were available for evaluation, including clinical and radiological outcome.

RESULTS

1 stem was revised for a periprosthetic fracture following trauma; 10 cups and 2 modular necks were revised (1 for breakage and 1 during cup revision). At 10 years, stem survival was 100%, modular neck survival was 99% (CI: 95-100), and cup survival was 94% (CI: 87-97). No leg length discrepancies were measured in 96% of cases. Offset with anatomic lateralization was achieved in 98%. Median Harris hip score was 94 (47-100) and median Merle d'Aubigné score was 16 (10-18). Relevant radiolucent lines and osteolysis were not found.

INTERPRETATION

The uncemented modular neck, dual-stem system used in this series allows accurate reconstruction of the joint by adapting the implant to the needs of the patient. This may improve the outcome of primary THA, which is supported by the results of this medium-term follow-up evaluation.

Cementless femoral components in young patients: review and meta-analysis of total hip arthroplasty and hip resurfacing

The study purpose was to analyze current results of modern cementless femoral components in young patients having total hip arthroplasty (THA) or hip resurfacing. Twenty-two studies (n = 5907; hips = 6408) evaluating modern cementless THA in young patients and 15 studies evaluating hip resurfacing (n = 3002; hips = 3269) were included. Meta-analysis techniques were used to pool failure rates. The pooled failure rate for THA using femoral revision for mechanical failure as an end point was 1.3% (95% confidence interval [CI], 1.0%-1.7%) at a mean 8.4 years of follow-up. At a mean of 3.9 years of follow-up, the pooled mechanical failure rate of the femoral component for hip resurfacing was 2.6% (95% CI, 2.0-3.4). In conclusion, the enthusiasm for hip resurfacing should be tempered by these data. Longer follow-up and direct comparison trials are required to confirm these findings.

Bone growth in rapid prototyped porous titanium implants

Two porous titanium implants with a pore size diameter of 800 and 1200 microm (Ti800 and Ti1200) and an interconnected network were manufactured using rapid prototyping. Their dimensions and structure matched those of the computer assisted design. The porosity of the implants was around 60%. Their compressive strength and Young's modulus were around 80 MPa and 2.7 GPa, respectively. These values are comparable to those of cortical bone. The implants were implanted bilaterally in the femoral epiphysis of 15 New Zealand White rabbits. After 3 and 8 weeks, abundant bone formation was found inside the rapid prototyped porous titanium implants. For the Ti1200 implants, bone ingrowth was (23.9 +/- 3.5)% and (10.3 +/- 2.8)%, respectively. A significant statistical difference (p < 0.05) was found for bone ingrowth in the Ti1200 between the two delays. The percentage of bone directly apposited on titanium was (35.8 +/- 5.4)% and (30.5 +/- 5.0)%. No significant difference was found for bone-implant contact between the different time periods and pore sizes. This work demonstrates that manufacturing macroporous titanium implants with controlled shape and porosity using a rapid prototyping method is possible and that this technique is a good candidate for orthopedic and maxillofacial applications.

Die Bedeutung der Gleitpaarung beim jüngeren Endoprothesenpatienten

The success and long-term survival rates of modern joint arthroplasty leads to a high patient satisfaction and, together with its technical improvements, has broadened the indications to an increasingly younger population. Limitations to the established systems are the long-term survival rates, which are mainly influenced by wear of the articulating parts and the resulting problems. Beside "classic" long-stemmed cemented shafts articulating with metal against polyethylene, short-stemmed or cup designs with a hard-hard self pairing are increasingly used in total hip arthroplasty. This paper reflects the current state of the art in joint arthroplasty for younger patients with the focus on wear couples and discusses future perspectives. Special interest is focused on the advantages and disadvantages of ceramic bearings, problems with allergies to implant components and the design of endoprostheses with regard to avoidance of impingement.