Alumina-on-alumina total hip prostheses in patients 40 years of age or younger

Long-term clinical results and patient satisfaction of a metaphyseal-engaging anatomic cementless femoral component in total hip arthroplasty

PURPOSE

There is relatively little information on the long-term clinical results of patients aged < 50 years with a contemporary total hip arthroplasty (THA), although a high rate of revision is projected for this group. Therefore, the purpose of this study was to evaluate the long-term results (a minimum of 21 years) of a metaphyseal-engaging anatomic cementless total hip prosthesis in patients aged < 50 years at the time of their THA.

METHODS

This study included 360 patients (498 hips), specifically 212 men and 148 women. The mean age of the patients at the time of their THA was 45.8 ± 8.1 years. The predominant diagnosis was osteonecrosis (56%). Demographic data, the Harris hip score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the University of California, Los Angeles (UCLA) activity score were recorded. Radiographic evaluation and dual-energy X-ray absorptiometry (DEXA) scanning were used to evaluate implant fixation, bone remodelling, and osteolysis. The mean follow-up was 25.2 year (range 21-28 years).

RESULTS

At the latest follow-up, the mean Harris hip, WOMAC, and UCLA activity scores were 93, 10, and 6.7 points, respectively. No patients had thigh pain. All hips had osseous integration of the acetabular and femoral components. No patient had grade 3 stress shielding. The 28-year survival rate was 98.2% (95% confidence interval [CI] 95-100%) for the acetabular components and 98.8% (95% CI 95-100%) for the femoral components. Overall, 90% of the patients were satisfied with the THA results.

CONCLUSION

The results suggest that a metaphyseal-engaging anatomic cementless femoral stem with alumina-on-alumina ceramic articulation provide outstanding long-term fixation and substantial pain relief well into the 3rd decade after surgery. Furthermore, there was no alumina ceramic fracture or osteolysis. Moreover, approximately 90% of the patients were satisfied with the results of their THA.

Similar Biomechanical Behavior in Gait Analysis between Ceramic-on-Ceramic and Ceramic-on-XLPE Total Hip Arthroplasties

In vitro measurements are widely used to implement gait kinematic and kinetic parameters to predict THA wear rate. Clinical tests of materials and designs are crucial to prove the accuracy and validate such measurements. This research aimed to examine the effect of CoC and CoXLPE kinematics and kinetics on wear during gait, the essential functional activity of humans, by comparing in vivo data to in vitro results. Our study hypothesis was that both implants would present the same hip joint kinematics and kinetics during gait. In total, 127 unilateral primary cementless total hip arthroplasties were included in the research. There were no statistically significant differences observed at mean peak abduction, flexion, and extension moments and THA kinematics between the two groups. THA gait kinematics and kinetics are crucial biomechanical inputs associated with implant wear. In vitro studies report less wear in CoC than CoXLPE when tested in a matched gait kinematic protocol. Our findings confirm that both implants behave identically in terms of kinematics in a clinical environment, thus strengthening CoC advantage in in vitro results. Correlated to all other significant factors that affect THA wear, it could address in a complete prism the wear on CoC and CoXLPE.

Ten-year survival of ceramic-on-ceramic total hip arthroplasty in patients younger than 60 years: a systematic review and meta-analysis

Background

Total hip arthroplasty (THA) with ceramic-on-ceramic (CoC) was created to minimise wear debris and aseptic loosening. A decade ago, a meta-analysis showed a 10-year survival rate of just 89%. Based on the excellent tribology of the current CoC, significant improvement of implant survivorship is expected. In patients younger than 60, we conducted a meta-analysis to assess 10-year survival and complications after using current primary CoC THA.

Materials and methods

PubMed, Scopus, EMBASE, Virtual Health Library, and Cochrane Library were used to scan for published trials that met the inclusion criteria until January 2019. The qualified studies were subjected to a systematic review and proportional analysis, and the randomised controlled trials (RCTs) were included in a comparison meta-analysis.

Results

Thirteen studies were included 156 findings. The total number of hips was 2278. Nine studies were cohort, and four were RCTs between ceramic and polyethylene cups. The analysis revealed an average age of 44 years (range 24–54). The 10-year survival 96% (95% CI; 95.4–96.8%), aseptic loosening rate 0.516. (95% CI; 0.265–0.903), ceramic fracture rate 0.620 (95% CI; 0.34–1.034) and squeaking rate 2.687 (95% CI; 1.279–4.593). A comparison meta-analysis revealed the risk ratio (RR) for revision was 0.27 (95% CI; 0.15–0.47), and for aseptic loosening 0.15 (0.03–0.70) favouring CoC, while RR for component fracture was 1.62 (95% CI; 0.27–9.66) favouring the polyethylene.

Conclusion

In patients under sixty, current CoC THAs are correlated with better 10-year outcomes than before and have high survivorship rates.

Level of evidence: Level I.

BIOMECHANICAL ASSESSMENT OF WEAR IN CERAMIC ON CERAMIC AND CERAMIC ON XLPE THAs

Total Hip Arthroplasty (THA) is an effective treatment for severe hip arthritis, with patients reporting high rates of satisfactory results postoperatively. There are a variety of choices regarding THA implant designs. Ceramic on Ceramic and Ceramic on Highly Cross-Linked Polyethylene (XLPE) THAs are the materials of choice nowadays. The purpose of this study is to review the effect of kinematics and kinetics on wear (in vivo and in vitro testing) that affect wear in Ceramic on Ceramic and Ceramic on XLPE total hip arthroplasties and identify possible advantages amongst them. The study hypothesis was that THA kinematics and/or kinetics, since they directly affect THA wear, could provide data for possible advantages between the examined implant designs. A systematic review of the literature identified no significant evidence for biomechanical advantages between these two prostheses in terms of wear. Further research is proposed with the use of gait analysis systems combined with surface electromyography to further investigate THA biomechanics at a laboratory set up. Wearable sensors technology could also identify detailed biomechanical parameters in more complex daily activities.

Ceramic-on-ceramic cementless total hip arthroplasty in patients aged 40 years or under: Do preoperative conditions affect long-term results?

INTRODUCTION

Underlying diseases, bone deformities and polyethylene wear affect outcome in young patients undergoing total hip arthroplasty (THA). These issues are not widely confirmed for ceramic - on-ceramic THA, particularly regarding cup fixation. Therefore, we did a retrospective long-term investigation on a large population of cementless ceramic-on-ceramic THA in patients aged 40 years or younger aiming to analyze: 1) the complication rate; 2) clinical results; and 3) survival for cup loosening with regard to their preoperative conditions.

HYPOTHESIS

Cup loosening could be related to preoperative diagnosis in young patients with a cementless ceramic-on-ceramic THA.

PATIENTS AND METHODS

Two hundred and seven hips in 171 patients (97 men and 74 women) underwent a cementless ceramic-on-ceramic THA at a mean age of 31.6±6.8 years. The most frequent diagnoses were avascular necrosis (AVN) of the femoral head (74 hips), pediatric hip diseases (35 hips), severe congenital hip dysplasia (CHD) (31 hips), juvenile rheumatoid arthritis (30 hips) and mild CHD (26 hips). The prosthesis included a press-fit metal backed cup with a hydroxyapatite coating and a macrotexture surface on either the equatorial region (93 cups) or the entire surface of the shell (114 cups). Ceramics were made of pure alumina and had a femoral head size of 28 (60 hips) or 32mm (147 hips). In all cases same the straight cementless tapered stem was inserted.

RESULTS

There were three early dislocations, one requiring cup revision No hip was revised due to infection, ceramic fracture, or femoral component loosening. Eight cups were revised for aseptic loosening (3,8%). The mean preoperative Harris Hip score was 52.8±6.2 and 93.4±6.9 at the end of follow-up. It was better in AVN (95.7±2.3) and worst in severe CHD (88.8±11.8) (p=0.001). If the end-point was cup aseptic loosening, the survival rate at 17 years was 95.1% (95% CI: 91.3-98.9), 100% for AVN and post-traumatic arthritis, and 86.8% (95% CI: 74.9-98.7) for severe CHD.

CONCLUSIONS

Despite diagnoses frequently causing technical difficulties at the surgery, outcome of cementless ceramic-on-ceramic THA in patients under the age of 40 years is satisfactory over ten years of follow up. Cup aseptic loosening was the main cause of failure and appears more related to the initial hip diseases than the age of the patient.

LEVEL OF EVIDENCE

III; retrospective comparative study.

Eighteen-Year Follow-Up Study of 2 Alternative Bearing Surfaces Used in Total Hip Arthroplasty in the Same Young Patients

BACKGROUND

This study compares the long-term functional, radiographic, and computed tomography scan outcomes and implant survivorship of ceramic-on-ceramic total hip arthroplasty (C-O-C THA) and ceramic-on-highly cross-linked polyethylene total hip arthroplasty (C-O-HXLPE THA) in the same patients.

METHODS

In this randomized, prospective trial conducted between January 1999 and April 2003, 133 patients (266 hips) younger than 55 years were enrolled. Each patient received C-O-C THA in 1 hip and a C-O-HXLPE THA in the other. The mean follow-up was 17.1 years (range, 15-18 years); there were 84 men and 49 women with a mean age of 53 ± 7 years (range, 25-55 years).

RESULTS

At the latest follow-up, mean Harris hip scores (94 vs 93 points; P = .861), pain scores (43 vs 42 points; P = .651), and patient satisfaction scores (7.8 vs 7.6 points; P = .379) were not different between the 2 groups. Eight hips (3%) in the C-O-C THA had an audible squeaking sound. The mean annual penetration rate of HXLPE was 0.0162 ± 0.032 mm per year. No osteolysis was recorded on radiographs or computed tomography scans in either group. At 17.1 years, the survival rate of the acetabular component was 97% in the C-O-C bearing group and 98% in the C-O-HXLPE bearing group (P = .923). The survival rate of the femoral component was 99% in both groups.

CONCLUSION

Both C-O-C THA and C-O-HXLPE THA functioned well, with no osteolysis at mean of 17.1-year follow-up.

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.

[Total hip replacement in avascular femoral head necrosis]

BACKGROUND

Avascular necrosis of the femoral head is a progressive perfusion disorder of the hip joint. Progress in avascular necrosis causes structural damage to the affected joint, often requiring total hip replacement.

AIM

This article is intended to give the reader an overview of the current literature on total hip replacement of patients with an avascular necrosis of the femoral head.

RESULTS

Before 1990, patients with avascular necrosis of the femoral head had significantly higher revision rates after total hip replacement. Recent studies, however, showed no significant differences in clinical outcomes after total hip replacement in femoral head necrosis and primary osteoarthritis. Despite the young age of the patients, good long-term clinical results can be expected even in patients with an avascular necrosis of the femoral head after total hip replacement.

Implant Survival and Patient-Reported Outcomes After Total Hip Arthroplasty in Young Patients

BACKGROUND

Younger patients are undergoing total hip arthroplasty (THA) for various conditions that affect the hip joint. This study evaluates the implant survival and long-term patient-reported outcomes of THA in patients aged 35 years or younger.

METHODS

Data were collected through a retrospective chart review, and follow-up surveys were conducted to determine implant survival and patient-reported outcomes. Kaplan-Meier survival analysis was performed to evaluate implant survival, and the hip disability and osteoarthritis outcome score (HOOS) was used to describe patient-reported outcomes. Descriptive statistics were used to summarize baseline and follow-up data, and univariate and multivariate analyses were used to compare implant survival and patient-reported outcomes.

RESULTS

This study included 400 patients (548 THAs). The average age at the time of surgery was 27 (range: 8-35) years, and the mean time to follow-up was 14 (range: 2-29.7) years. The 10- and 20-year implant survival was 87% and 61%, respectively. Implant survival differed based on primary diagnosis (P = .05), and it was significantly better in patients aged 25 years or older at the time of surgery, male patients, and patients with ceramic-on-ceramic or ceramic-on-plastic implants (P < .05). Mean HOOS scores at follow-up were 86 for pain, 84 for symptoms, 86 for ADLs, and 77 for sports. All HOOS scores were significantly worse after revision THA (P < .01).

CONCLUSION

Young patients have good implant survival and favorable long-term outcomes after THA. There are several predictors of implant survival and patient-reported outcomes after THA in young patients.

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantagesCoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion.However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with fracture of a component.We recommend that surgeons weigh the potential advantages and disadvantages of current CoC THA in comparison with other bearing surfaces when considering young very active patients who are candidates for THA. Cite this article: Hernigou P, Roubineau F, Bouthors C, Flouzat-Lachaniette C-H. What every surgeon should know about Ceramic-on-Ceramic bearings in young patients. EFORT Open Rev 2016;1:107-111. DOI: 10.1302/2058-5241.1.000027.

Highly cross-linked polyethylene improves wear and mid-term failure rates for young total hip arthroplasty patients

We compared clinical outcomes and polyethylene wear for 2 young primary THA patient cohorts (<50 years of age) at mid-term follow-up. In total, 72 patients (84 hips) received a coventional polyethylene liner (CPE) and 84 patients (89 hips) received a highly cross-linked polyethylene liner (HXLPE). Mean Harris Hip Score improved to 81 points for both groups. UCLA activity scores were higher for HXLPE patients (6.0 vs 5.3, p = 0.03), with lower mean linear wear (0.02 vs 0.13 mm/year, p<0.001) and lower mean volumetric wear (75.1 vs 229.8 mm3, p<0.001) at an average of 70 months follow-up. No HXLPE patient required revision for wear related concerns, compared to 5 CPE patients with revision for aseptic loosening or impending radiographic failure (0% vs 5.9%, p = 0.02). HXLPE is associated with reduced wear among young, active THA patients without increased risk of early mechanical failure.

Ceramic on Ceramic or Ceramic-on-polyethylene for Total Hip Arthroplasty: A Systemic Review and Meta-analysis of Prospective Randomized Studies

BACKGROUND

Wear debris of polyethylene has become a restraining factor of the durability for total hip arthroplasty (THA). Ceramic on ceramic (COC) has better wear resistance while the squeaking sound and prosthesis fracture are of concern. It is still a controversy that bearing couples are better for THA.

METHODS

We performed a systematic review of all English articles identified from PubMed (1966-), Embase (1980-) and the Cochrane Library. Clinical outcomes, complications, revision rates, and radiographic outcomes of COC-THA and ceramic on polyethylene (COP)-THA were compared and evaluated.

RESULTS

Eight prospective randomized trials enrolling a total of 1508 patients and 1702 THA surgeries were identified. Our results demonstrated the prosthesis fracture and the squeaking sound is significantly higher in COC group and higher wear rate of the COP. Hip function, loosening rate, dislocation rate, revision rate, and the osteolysis rate were comparable between two groups. According to Grading of Recommendations Assessment, Development and Evaluation system assessment, the strength of evidence was high for prosthesis fracture, dislocation, osteolysis, and moderate for radiolucent line or loosening, hip noise, and revision.

CONCLUSIONS

Up to now, there is insufficient evidence to identify any clinical advantage of COC compared with COP. Longer follow-up of larger randomized trial is needed to clarify the outcomes.

Aluminum and bone: Review of new clinical circumstances associated with Al(3+) deposition in the calcified matrix of bone

Several decades ago, aluminum encephalopathy associated with osteomalacia has been recognized as the major complication of chronic renal failure in dialyzed patients. Removal of aluminum from the dialysate has led to a disappearance of the disease. However, aluminum deposit occurs in the hydroxyapatite of the bone matrix in some clinical circumstances that are presented in this review. We have encountered aluminum in bone in patients with an increased intestinal permeability (coeliac disease), or in the case of prolonged administration of aluminum anti-acid drugs. A colocalisation of aluminum with iron was also noted in cases of hemochromatosis and sickle cell anemia. Aluminium was also identified in a series of patients with exostosis, a frequent benign bone tumor. Corrosion of prosthetic implants composed of grade V titanium (TA6V is an alloy containing 6% aluminum and 4% vanadium) was also observed in a series of hip or knee revisions. Aluminum can be identified in undecalcified bone matrix stained by solochrome azurine, a highly specific stain allowing the detection of 0.03 atomic %. Colocalization of aluminum and iron does not seem to be the fruit of chance but the cellular and molecular mechanisms are still poorly understood. Histochemistry is superior to spectroscopic analyses (EDS and WDS in scanning electron microscopy).

Ceramic-on-ceramic THA associated with fewer dislocations and less muscle degeneration by preserving muscle progenitors

BACKGROUND

Dislocation is a common complication after total hip arthroplasty (THA). Although the etiology of dislocation is multifactorial, longer-term changes in muscle such as atrophy may influence the risk of prosthetic dislocation. Biological differences in wear products generated by different bearing surfaces may influence differences in the appearance of periarticular muscle after THA; however, such bearing-associated differences to our knowledge have not been studied in vivo, and few studies have evaluated bearing-associated differences in dislocation risk.

QUESTIONS/PURPOSES

(1) Is there a correlation between the postoperative risk of dislocation at revision and the bearing surfaces of the primary arthroplasty? (2) Is there a higher extent of fatty muscle atrophy on CT scan in hips with osteolysis (polyethylene hips) as compared with hips without osteolysis (ceramic-on-ceramic hips)? (3) Are these two abnormalities (bone osteolysis and fatty atrophy) associated with a decrease of mesenchymal stem cells (MSCs) in bone and in muscle?

METHODS

We retrospectively evaluated 240 patients (240 hips) who had a THA revision (98% of which, 235 of the 240, were isolated acetabular revisions) and a normal contralateral hip. All patients had received the same implants for the primary arthroplasty (32-mm head) except for bearing surfaces (80 hips with ceramic-on-ceramic, 160 with polyethylene). No differences were noted between the groups in terms of age, sex, body mass index, proportion of patients who had a dislocation after the index arthroplasty but before the revision, and proportion of the patients with stem loosening in addition to acetabular loosening. Indications for revision generally were cup loosening. The revisions in the hips with polyethylene bearings generally had more acetabular bone loss, but the position of the center of the cup and the orientation of the cup were similar after reconstruction in the two groups. Before revision, osteolysis, muscle atrophy, and fatty degeneration were evaluated on CT scan and compared with the contralateral side. Bone muscle progenitors were evaluated by bone marrow MSCs and satellite cells for muscle. At revision, all the hips received the same implants with the same head diameter (32 mm) and a standard liner. Revisions were performed between 1995 and 2005. The followup after revision was at a mean of 14 years (range, 10-20 years) for ceramic revision and 12 years (range, 10-20 years) for polyethylene hips, and there was no differential loss to followup between the groups.

RESULTS

More hips with polyethylene liners at the time of index arthroplasty dislocated after revision than did hips with ceramic liners (18% [29 of 160] compared with 1% [one of 80]; odds ratio, 17.5; 95% confidence interval, 2.3363-130.9100; p = 0.005). For the 80 hips with ceramic-on-ceramic, no osteolysis was detected before revision; there was no muscle fatty degeneration of the gluteus muscles on CT scan or histology. For the 160 hips with polyethylene liners, osteolytic lesions on the acetabulum and femur were observed in 100% of the hips. The increased atrophy of the gluteus muscles observed on CT scan correlated with the increase of osteolysis (r = 0.62; p = 0.012). The surgical limbs in the patients with polyethylene hips as compared with ceramic-on-ceramic hips demonstrated a greater reduction in cross-sectional area (respectively, 11.6% compared with 3%; odds ratio, 3.82; p < 0.001) and radiological density (41% [14.1/34.1] compared with 9%; odds ratio, 6.8; p = 0.006) of gluteus muscles when compared with the contralateral normal side. (41% compared with 9%; odds ratio, 6.8; p = 0.006).

CONCLUSIONS

Ceramic bearing surfaces were associated with fewer dislocations after revision than polyethylene bearing surfaces. The reasons of the lower rate of dislocation with ceramic-on-ceramic bearings may be related to observed differences in the periarticular muscles (fat atrophy or not) with the two bearing surfaces.

LEVEL OF EVIDENCE

Level III, therapeutic study.

How have alternative bearings and modularity affected revision rates in total hip arthroplasty?

BACKGROUND

Total hip arthroplasty (THA) continues to be one of the most successful surgical procedures in the medical field. However, over the last two decades, the use of modularity and alternative bearings in THA has become routine. Given the known problems associated with hard-on-hard bearing couples, including taper failures with more modular stem designs, local and systemic effects from metal-on-metal bearings, and fractures with ceramic-on-ceramic bearings, it is not known whether in aggregate the survivorship of these implants is better or worse than the metal-on-polyethylene bearings that they sought to replace.

QUESTIONS/PURPOSES

Have alternative bearings (metal-on-metal and ceramic-on-ceramic) and implant modularity decreased revision rates of primary THAs?

METHODS

In this systematic review of MEDLINE and EMBASE, we used several Boolean search strings for each topic and surveyed national registry data from English-speaking countries. Clinical research (Level IV or higher) with ≥ 5 years of followup was included; retrieval studies and case reports were excluded. We included registry data at ≥ 7 years followup. A total of 32 studies (and five registry reports) on metal-on-metal, 19 studies (and five registry reports) on ceramic-on-ceramic, and 20 studies (and one registry report) on modular stem designs met inclusion criteria and were evaluated in detail. Insufficient data were available on metal-on-ceramic and ceramic-on-metal implants, and monoblock acetabular designs were evaluated in another recent systematic review so these were not evaluated here.

RESULTS

There was no evidence in the literature that alternative bearings (either metal-on-metal or ceramic-on-ceramic) in THA have decreased revision rates. Registry data, however, showed that large head metal-on-metal implants have lower 7- to 10-year survivorship than do standard bearings. In THA, modular exchangeable femoral neck implants had a lower 10-year survival rate in both literature reviews and in registry data compared with combined registry primary THA implant survivorship.

CONCLUSIONS

Despite improvements in implant technology, there is no evidence that alternative bearings or modularity have resulted in decreased THA revision rates after 5 years. In fact, both large head metal-on-metal THA and added modularity may well lower survivorship and should only be used in select cases in which the mission cannot be achieved without it. Based on this experience, followup and/or postmarket surveillance studies should have a duration of at least 5 years before introducing new alternative bearings or modularity on a widespread scale.

Systematic review of total hip arthroplasty in patients under 30 years old

We performed a systematic review to assess whether joint replacement in this very 
young patient group provides significant functional improvement and whether these procedures are associated with good implant survivorship. The studies included presented the results of 
450 THA procedures. All patients showed an improvement in functional score and symptom relief. Uncemented stems showed good integration with no signs of loosening. Cemented implants showed high rates of loosening. This study shows that THA in the very young patient can provide good functional improvement and relief of symptoms and that the more modern uncemented implant designs used with hard-on-hard bearings can be associated with improved implant survival. Long-term studies are necessary to confirm the superiority and improved survivorship of these newer 
implants.

Ceramic-on-ceramic bearing decreases the cumulative long-term risk of dislocation

BACKGROUND

It is unclear whether late THA dislocations are related to mechanical impingement or to a biological mechanism that decreases the stability provided by the capsule (eg, inflammation secondary to osteolysis). It is also unknown if alumina-on-alumina bearing couples decrease the risk of late dislocation as a result of the absence of wear and osteolysis.

QUESTION/PURPOSES

We asked (1) whether the cumulative number of dislocations differed with alumina-on-alumina (AL/AL) or alumina-on-polyethylene bearings (AL/PE); (2) whether patient factors (age, sex, and diseases) affect risk of late dislocation; (3) whether mechanical factors (component malposition, penetration resulting from creep and wear) or (4) biologic hip factors at revision (thickness of the capsule, volume of joint fluid removed at surgery, histology) differed with the two bearing couples.

METHODS

One hundred twenty-six patients (252 hips) with bilateral THA (one AL/AL and the contralateral AL/PE) received the same cemented implants except for the cup PE cup or an AL cup. The cumulative risk of dislocation (first-time and recurrent dislocation) was calculated at a minimum of 27 years. We measured cup position, creep and wear, and capsular thickness in the hips that had revision.

RESULTS

AL/PE and AL/AL hips differed by the cumulative number of dislocation (31 with AL/PE versus four with AL/AL) and by the number of late dislocations (none with AL/AL, 28 with AL/PE). Cause of osteonecrosis, age, and sex affected the number of dislocations. The frequency of component malposition did not differ between the two bearing couples. The risk of late dislocation appeared less in AL/AL hips with increased capsular thickness (mean, 4.5 mm; range, 3-7 mm) compared with the thinnest (mean, 1.2 mm; range, 0.2-2 mm) capsule of AL/PE hips.

CONCLUSIONS

AL/AL bearing couples decreased the cumulative risk of dislocation as compared with AL/PE bearing couples.

A randomised prospective evaluation of ceramic-on-ceramic and ceramic-on-highly cross-linked polyethylene bearings in the same patients with primary cementless total hip arthroplasty

PURPOSE

Very few studies have compared alumina-on-alumina ceramic and alumina-on-highly cross-linked polyethylene bearings in the same patient. The purpose of this prospective randomised study was to compare the clinical and radiographic results and the prevalence of osteolysis in cementless total hip arthroplasty using an alumina-on-alumina and alumina-on-highly cross-linked polyethylene bearings in young active patients.

METHODS

We prospectively compared the results of 100 patients (200 hips) who had undergone a cementless total hip arthroplasty with an alumina-on-alumina ceramic bearing in one hip and an alumina-on-highly cross-linked polyethylene in the other. There were 66 men and 34 women with a mean age of 45.3 years (range, 21-49 years) at the time of surgery. The mean follow-up was 12.4 years (range, 11-13 years). The patients were assessed clinically and radiographically at three months, one year, and annually thereafter.

RESULTS

Harris hip, Western Ontario and McMaster Universities Osteoarthritis Index, and University of California, Los Angeles activity scores did not show statistically significant differences between the two groups of bearings preoperatively or at the time of final follow-up. Radiographic findings of the component were not significantly different between the two groups. The mean polyethylene linear penetration was 0.031 ± 0.004 mm per year. No hips in either group displayed osteolysis. The Kaplan-Meier survivorship with revision as the end point at 12.4 years was 100% (95% confidence interval [CI], 94-100%) for the femoral component in both groups and 99% (95%CI, 93-100%) for the acetabular component.

CONCLUSION

The clinical and radiographic results of using an alumina-on-alumina ceramic and alumina-on-highly cross-linked polyethylene bearings were similar.

Total hip arthroplasty in teenagers: an alternative to hip arthrodesis

Debilitating arthritis in teenage patients is a complex problem with limited surgical options. Hip arthrodesis is unpopular amongst patients, and contemporary total hip arthroplasty (THA) may be a promising alternative. We report on the outcomes of THA in patients less than 20 years of age. All consecutive teenage patients undergoing THA at a tertiary referral centre were reviewed. Mean follow-up was 3.4 years (range 0.6-6.8) and 9 patients had at least 5 years follow-up. There were 51 THAs in 43 patients with a mean age of 17 years (range 12-19). The commonest indication was osteonecrosis (35 cases), mostly secondary to slipped upper femoral epiphysis (15 cases). Forty-six were uncemented and 5 were reverse hybrid THAs of which 7 were computer assisted design/manufacture (CADCAM) components. The commonest bearing surface used was ceramic on ceramic (40 cases). The survival rate was 96% and there were 2 complications. At latest follow-up, the mean Harris hip score was 90 (range 68-99) and UCLA activity score was 6 (range 4-9). Radiological analysis showed 2 patients with lucent lines around the acetabular component, but no signs of osteolysis or wear. We report good short to intermediate term survivorship and outcomes, and feel THA represents a valid alternative option to hip arthrodesis.

National trends in primary total hip arthroplasty in extremely young patients: a focus on bearing surface usage

The purpose of this study was to present national trends in primary total hip arthroplasty (THA) and bearing surface usage for patients 30 years and younger. Using the Healthcare-Cost-and-Utilization-Project Nationwide Inpatient Sample for the years 2006 to 2009, 8919 primary THA discharges (4454 coded by bearing surface) were identified in patients 30 years and younger. The most commonly used bearing surface was metal-on-metal (MoM), representing 37.6% of cases, followed by ceramic-on-ceramic (CoC) (24.6%), metal-on-polyethylene (MoP) (22.1%) and ceramic-on-polyethylene (15.7%). From 2006 to 2009, the percentage of THAs that used hard-on-hard bearing surfaces decreased (MoM: 42.9%-29.4%; CoC: 34.0%-19.7%).This decrease in hard-on-hard bearing surface usage presents a challenge for surgeons treating young patients to find other acceptable durable bearings that do not have the potential problems associated with MoM or CoC.

Alumina-on-alumina THA performed in patients younger than 30 years: a 10-year minimum followup study

BACKGROUND

THA in patients younger than 30 years presents challenges because of uncertainties regarding the long-term survivorship of prostheses. Alumina-on-alumina bearings, which exhibit little long-term wear, may be a reasonable option but the long-term survivorship is unknown.

QUESTIONS/PURPOSES

We determined (1) the survival rate of alumina-on-alumina bearings in patients younger than 30 years after a 10-year followup, (2) the incidence of audible hip clicking and squeaking, (3) radiographic evidence of osteolysis, and (4) the effects on pregnancy, childbirth, and career choice.

METHODS

We retrospectively reviewed 62 patients who had 75 THAs with alumina-on-alumina bearings followed more than 10 years (average, 11.5; range, 10-13.5 years). Mean patient age at the time of surgery was 24 years (range, 18-30 years). All operations were performed using the same cementless implant at a single center. We determined survival, presence of osteolysis, and function (Harris hip score, WOMAC).

RESULTS

The 10-year survival rate of alumina-on-alumina bearings in THAs, with revision for any reason as the end point, was 98.9%. Audible hip clicking and squeaking were identified in 10 hips and two hips, respectively. No osteolysis was detected. None of the 11 patients who became pregnant had been affected by their THA during pregnancy or childbirth. Seven of the 14 patients who were unemployed at the time of index surgery stated that their THA affected their job choice.

CONCLUSIONS

We found a high 10-year survival of cementless alumina-on-alumina bearings in THAs in patients younger than 30 years. Lifetime events such as job choice, pregnancy, and childbirth should be considered when choosing THA for patients younger than 30 years.

LEVEL OF EVIDENCE

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

Comparative effectiveness of metal-on-metal and metal-on-polyethylene bearings in Medicare total hip arthroplasty patients

The purpose of this study was to compare the risk of complication and revision total hip arthroplasty (THA) in Medicare THA patients with different bearings. Using the 100% Medicare database (2005-2009), the adjusted risk of complication and revision THA was calculated for 148,827 THA patients (93,929 metal-on-polyethylene, 49,646 metal-on-metal, 5252 ceramic-on ceramic). Adjusted risk of deep vein thrombosis, dislocation, periprosthetic joint infection (PJI), mechanical loosening, periprosthetic fracture, and revision THA at up to 4 years postoperatively was compared using Cox regression. After adjusting for patient and hospital factors, metal-on-metal bearings were associated with higher risk of PJI (P = .001), mechanical loosening (P < .001), and deep vein thrombosis (P = .031) than metal-on-polyethylene bearings and higher risk of PJI (P = .014) than ceramic-on-ceramic bearings. Overall short-term revision rates did not vary significantly across bearing types, consistent with registry data. The benefits of hard-on-hard bearings in Medicare patients remain unproven, and further study is needed to compare long-term complication and revision rates in Medicare THA patients with different bearing types.

Large-diameter Delta ceramic-on-ceramic versus common-sized ceramic-on-polyethylene bearings in THA

The higher failure rate of total hip arthroplasty (THA) in young, active patients remains a challenge for surgeons. Recently, larger-diameter femoral heads combined with an alumina matrix composite ceramic (BIOLOX Delta; CeramTec AG, Plochingen, Germany) articulation was developed to improve implant longevity and meet patients' activity demands while reducing the risk of component-related complications. The purpose of this study was to determine whether this new device may provide advantages for young, active patients. A prospective, randomized, controlled trial was conducted on 93 patients (113 THAs) with more than 3 years of follow-up. Patients were randomly divided into a study group (51 THAs) with a 36-mm Delta ceramic-on-ceramic (COC) articulation and a control group (62 THAs) with a common-sized alumina ceramic head on polyethylene liner (COP) articulation. Clinical and radiographic results were collected to compare the outcomes and complications, including implant-related failures, osteolysis, and noises. The large-diameter Delta COC articulation provided greater range of motion improvement (6.1° more), similar Harris Hip Scores, and similar complication rates compared with the alumina COP articulation. This study suggests that in the short term, the large-diameter Delta COC articulation results in better range of motion with no higher complication rates; however, mid-term (8-10 years) or longer follow-up is necessary to determine its superiority in young, active patients.

Cementless acetabular fixation in patients 50 years and younger at 10 to 18 years of follow-up

The purpose of the study was to evaluate the 10- to 18-year follow-up of cementless acetabular fixation in patients 50 years and younger. We retrospectively reviewed a consecutive group of 118 patients (144 hips) in whom primary total hip arthroplasty had been performed by 2 surgeons using a cementless acetabular component. Two (1.4%) cementless acetabular components were revised because of aseptic loosening. Twenty-four hips (16.7%) were revised for any mechanical failure of the acetabular component mostly related to acetabular liner wear and osteolysis. The average linear wear rate was 0.19 mm per year, which was higher than our previous reports with cemented acetabular fixation. The fiber mesh ingrowth surface of the cementless acetabular component in this study was superior to cemented acetabular components in terms of fixation. However, the high rates of wear and osteolysis have led to poor overall acetabular component construct survivorship.

Third-generation ceramic-on-ceramic total hip arthroplasty in patients younger than 30 years with osteonecrosis of femoral head

The purpose of this study was to evaluate the functional and radiographic results of patients younger than 30 years who underwent cementless third-generation ceramic-on-ceramic total hip arthroplasty for osteonecrosis of the femoral head. Forty-one patients (56 hips) with a minimum follow-up of 6 years were included. In all cases, third-generation ceramic-on-ceramic articulation was used. Average Harris Hip Scores improved from 52.9 preoperatively to 98.2, and Western Ontario and McMaster Universities Osteoarthritis Index score, from 95.2 to 25.2. Thirty-nine patients returned to their normal occupations. No aseptic loosening or osteolysis was observed. Total hip arthroplasty performed using third-generation ceramic-on-ceramic bearings for osteonecrosis of femoral head was found to provide satisfactory clinical and radiologic results, especially in active, young patients.

Bearing surface considerations for total hip arthroplasty in young patients

Bearing selection for total hip arthroplasty in young patients is important because of the likely long service life of the implant. Careful consideration of the next operation is recommended when choosing components. No prospective, randomized studies exist that document the clear superiority of any bearing couple in young, active patients. Modern metals, ceramics, and polyethylenes all hold promise. Further long-term data on modern bearings are needed to determine the clinical performance of these bearings. This article summarizes the available data on various bearing couples in patients aged younger than 50 years.

Ceramic-on-ceramic total hip arthroplasty in patients younger than 20 years

Total hip arthroplasty (THA) in the adolescent patient has historically shown relatively poor survivorship. This study reports the results of THA in young patients using contemporary ceramic bearings. Twenty-four THAs were performed using ceramic bearing surfaces in patients 20 years old or younger (mean, 16.4; range, 12-20). Average follow-up was 52 months (range, 25-123 months). The survival rate was 96%, with 1 revision for a loose acetabular component. Other complications included a peroneal nerve palsy that resolved and 2 dislocations in 1 patient. Postoperatively, the Modified Harris Hip Score mean was 93.4 (range, 66-100). This study shows promising results at short-term to midterm follow-up in very young patients who undergo THA using ceramic-on-ceramic components.

A prospective short-term outcome study of a short metaphyseal fitting total hip arthroplasty

The purpose of this study was to determine whether the short, metaphyseal fitting femoral stem would achieve stable fixation without diaphyseal fixation. A total of 126 patients (144 hips) were included in the study, and their mean age was 53.9 years (26-65 years). The mean duration of follow-up was 4.5 years (4-5 years). The predominant diagnosis was osteonecrosis of femoral head (88 of 144 hips, or 61%). The mean preoperative Harris hip score was 45 points, which improved to 96 points by the final follow-up. Western Ontario and McMaster Universities Osteoarthritis score and patient's activity score were improved substantially at the final follow-up. This short, metaphyseal fitting cementless femoral component achieved stable fixation without diaphyseal fixation, and there was minimal stress-shielding bone resorption in the calcar region.

New method for determining in vitro structure stiffness of ceramic acetabular liners under different impact conditions

Increasing both patient mobility and prosthesis life span requires improvements in the range of motion and wear behavior of the liner. With the use of new composite alumina-zirconia ceramic materials, the same stability of the liner can be achieved at lower wall thickness than it is possible with alumina-only materials. The aim of this study was developing a method for determining the in vitro structure stiffness of ceramic acetabular liners against impact stresses. The first trials were performed with a common alumina acetabular liner type (Ceramtec; Biolox forte; diameter 28 mm; thickness 7 mm) and a new type of alumina-zirconia (Ceramtec Biolox delta; same dimensions) liner. The clinically established alumina liner was reproducibly damaged using worst case Separation/subluxation equivalent to one-fourth or half of the head diameter, and an impact load of 15 J. The liners containing the new alumina-zirconia material were not damaged in any of the trials up to an impact load of 20 J and half head diameter offset.

Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty

Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings.

What is the midterm survivorship and function after hip resurfacing?

BACKGROUND

Hip resurfacing arthroplasty is a common procedure that improves functional scores and has a reported survivorship between 95% and 98% at 5 years. However, most studies are reported from the pioneering rather than independent centers or have relatively small patient numbers or less than five years followup. Various factors have been implicated in early failure.

QUESTIONS/PURPOSES

Our purposes were to determine: (1) the midterm survival of the BHR; (2) the function in patients treated with hip resurfacing; and (3) whether age, gender, BMI, or size of components related to failure.

METHODS

We reviewed the first 302 patients (329 hips) on whom we performed resurfacing arthroplasty. We assessed the survivorship, change in functional hip scores (HHS, OHS, WOMAC, UCLA), and analyzed potential risk factors (age, gender, BMI, component size) for failure. The mean age at the time of surgery was 56.0 years (range, 28.2-75.5 years). The minimum followup was 5 years (mean, 6.6 years; range, 5-9.2 years).

RESULTS

Kaplan-Meier analysis showed survival of 96.5% (95% CI, 94.7-98.4) at 9 years taking revision for any cause as the endpoint. All functional hip scores (HHS, OHS, WOMAC, UCLA) improved. Survivorship was higher in men compared with women. The component sizes and body mass index were smaller in the revised group compared with the nonrevised group.

CONCLUSIONS

Medium-term survivorship and functional scores of hip resurfacing are comparable to those from the pioneering center. Hip resurfacing remains a good alternative to THA, particularly in the younger male population with relatively large femoral head sizes.

Is alumina-on-alumina ceramic bearings total hip replacement the right choice in patients younger than 50 years of age? A 7- to 15-year follow-up study

INTRODUCTION

The alumina-on-alumina bearing couple in total hip replacement seems to be well adapted for young and active patients because of the absence of wear and the rarity of osteolysis. Over the long term, doubts persist as to the cementless cup fixation and on the functioning of this bearing system because of possible acoustic emissions during use.

HYPOTHESIS

In young subjects, the ceramic-on-ceramic bearing system limits wear and osteolysis occurrences, without exposing patients to serious side effects. MATERIAL AND MEHTODS: We report the results, with between 7 and 15 years of follow-up, for 32mm-diameter alumina-on-alumina implants in 76 patients younger than 50 years of age (83 hips), combining cementless press-fit hemispheric cups with titanium stems, [either cemented (63 Osteal™ stems) or cementless (20 Multicône™ stems)], with particular attention paid to cup fixation and noise emissions during implant function. First-generation or Cerafit trellis™ acetabular components had a riveted titanium mesh (31 cases), whereas the most recent (Cerafit hydroxyapatite [HA]™) cups had a porous surface coated with hydroxyapatite (52 cases).

RESULTS

Three cases of aseptic loosening of the cemented stems were observed as well as late migration of a Cerafit trellis™ cup in the 12th postoperative year. One ceramic insert broke in the eighth postoperative year. With the exception of one case, the patients, questioned retrospectively, reported no audible noise. With aseptic loosening (revised or not), the criterion for failure, the 12-year survival rate was 91±11% for the Cerafit trellis™ acetabular components and 91±16% for the cemented Osteal™ stems. The 9- and 7-year survival rates for the Cerafit HA™ cups and the Multicône™ stems, respectively, were 100%. Including all revisions for any cause, the 10-year survival rate of the entire series was 92%±11%.

DISCUSSION

Despite the absence of wear and osteolysis, the long-term survival of these implants in young subjects should be improved. Although longer follow-up is necessary to formulate a definitive opinion, we tend to prefer cementless stem and cup fixation in ceramic-on-ceramic bearing systems.

LEVEL OF EVIDENCE

Level 4 retrospective study.

Optimal bearing surfaces for total hip replacement in the young patient: a meta-analysis

Although there is general consensus about the efficacy of total hip replacement (THR) in young patients, the most appropriate bearings in young patients remain highly debated. The three most popular bearings in use include metal-on-polyethylene (MOP), metal-on-metal (MOM) and ceramic-on-ceramic (COC). We conducted a systematic review and meta-analysis of literature to summarise the best available evidence on relative success of the three most popular bearings used in THR in young active patients. Our findings support the use of MOM bearings in the management of the young arthritic hip. These findings, largely based upon observational studies, should be taken in the context of the limitations of such non-randomised study designs.

Revision total hip arthroplasty for ceramic head fracture: a long-term follow-up

The results of revision total hip arthroplasty (THA) for ceramic head fracture have generally been disappointing, largely due to third body wear after incomplete synovectomy. We have followed 8 patients who sustained ceramic head fractures and were subsequently revised to a metal-on-polyethylene articulation. There were no revisions for osteolysis or aseptic loosening at a mean follow-up of 10.5 years. The yearly wear rates of each of 5 of these THAs after revision were compared with 6 matched metal-on-polyethylene THAs; there were no significant differences in wear rates. Greater than 10-year survivorship with a metal-on-polyethylene bearing couple is possible after revision THA for a ceramic head fracture if a complete and thorough synovectomy can be performed. Our technique of synovectomy will be described.

Ceramic-ceramic bearing decreases osteolysis: a 20-year study versus ceramic-polyethylene on the contralateral hip

Although ceramic implants have been in use for many years and they are intended to minimize wear debris it is unknown whether alumina-on-alumina or alumina-on-polyethylene produce less wear and osteolysis. We therefore investigated wear and osteolysis on 28 bilateral arthroplasties (one ceramic-ceramic and the contralateral ceramic-polyethylene) of patients who had survived 20 years without revision and without loosening of either hip. Osteolysis was identified on anteroposterior pelvic radiographs and 3-D volume from CT scans. The number of osteolytic lesions detected with CT scan was higher than with radiographs. The number of lesions was higher on the side with the alumina-PE couple. With a similar length of followup on each side, the surface and the volume of osteolysis were consistently higher on the side with the alumina-PE couple. We found no correlation between the volume of osteolysis and the volume of estimated wear in each couple of friction. Hips with osteolysis had a lower Harris score.

Alumina-on-alumina total hip arthroplasty in young patients: diagnosis is more important than age

Total hip arthroplasty (THA) in young patients has a high loosening rate, due in part to acetabular deformities that may compromise bone fixation and polyethylene wear. We therefore asked whether wear or osteolysis and loosening differ in patients under 40 years of age with alumina-on-alumina THA compared to those who are older. We prospectively followed 56 patients (63 hips) younger than 40 years (Group 1) and 247 patients (274 hips) older than 40 (Group 2) who had an alumina-on-alumina THA. The minimum followup was 4 years (mean, 5.6 years; range, 4-9 years). The two groups differed in various features: there were no patients with primary osteoarthritis in Group 1 and they had worse preoperative function and range of mobility, while weight, activity level, and implant size were greater in Group 2. The survival rate for cup loosening at 80 months postsurgery was 90.8% (95% confidence interval, 82.9-98.6%) for Group 1 and 96.5% (95% confidence interval, 94.2-98.7%) for Group 2. Cup loosening was less frequent with primary osteoarthritis than with severe developmental dysplasia of the hip. Although an alumina-on-alumina THA provided similar midterm survival and radiographic loosening in both age groups, the preoperative diagnosis seems more important than age for outcome. Continued followup will be required to determine if the alumina-on-alumina bearings in young patients result less risk of osteolysis and loosening.

Cemented polyethylene cups in patients younger than 40 years

Although uncemented cup implants frequently are used in young patients, we believe long-term survival rates of cups in these patients are somewhat disappointing, and therefore we have continued to use cemented cups in primary THA, even in young patients. However, in cases of acetabular bone stock defects, we also use bone impaction grafting. We prospectively followed 130 patients with 175 cemented cups; no patients were lost to followup. The mean age of the patients at surgery was 31 years (range, 16-39 years). An acetabular reconstruction with bone impaction grafting was performed in 84 hips (48%). The minimum followup was 2 years (average, 8.1 years; range, 2.0-18.5 years). Twenty-one of the 175 cups (12%) were revised at an average of 8.1 years (range, 2.0-18.5 years). Reasons for revision were infection (one early, seven late), recurrent dislocations (two), traumatic loosening (one), and aseptic loosening (10). The 10-year survival rate of all cemented cups with end point of revision for any cause was 85%. Survival with end point of aseptic loosening of all cups was 92%. Survival with end point of revision for aseptic loosening was 90% for the cups without impaction grafting and 95% for the cups with impaction grafting. We believe cemented acetabular cups in young patients have acceptable midterm survival; however, in the case of acetabular bone defects, we recommend reconstruction with impaction grafting.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The epidemiology of bearing surface usage in total hip arthroplasty in the United States

BACKGROUND

Hard-on-hard bearings offer the potential to improve the survivorship of total hip arthroplasty implants. However, the specific indications for the use of these advanced technologies remain controversial. The purpose of this study was to characterize the epidemiology of bearing surface utilization in total hip arthroplasty in the United States with respect to patient, hospital, geographic, and payer characteristics.

METHODS

The Nationwide Inpatient Sample database was used to analyze bearing type and demographic characteristics associated with 112,095 primary total hip arthroplasties performed in the United States between October 1, 2005, and December 31, 2006. The prevalence of each type of total hip arthroplasty bearing was calculated for population subgroups as a function of age, sex, census region, payer class, and hospital type.

RESULTS

The most commonly reported bearing was metal-on-polyethylene (51%) followed by metal-on-metal (35%) and ceramic-on-ceramic (14%). Metal-on-polyethylene bearings were most commonly reported in female Medicare patients who were sixty-five to seventy-four years old, while metal-on-metal and ceramic-on-ceramic bearings were most commonly reported in privately insured male patients who were less than sixty-five years old. Thirty-three percent of patients over sixty-five years old had a hard-on-hard bearing reported. There was substantial regional variation in bearing usage; the highest prevalence of metal-on-polyethylene bearings was reported in the Northeast and at nonteaching hospitals, and the highest prevalence of metal-on-metal bearings was reported in the South and at teaching hospitals.

CONCLUSIONS

The usage of total hip arthroplasty bearings varies considerably by patient characteristics, hospital type, and geographic location throughout the United States. Despite uncertain advantages in older patients, hard-on-hard bearings are commonly used in patients over the age of sixty-five years. Further study is necessary to define the appropriate indications for these advanced technologies in total hip arthroplasty.

Osteolysis in third-generation alumina ceramic-on-ceramic hip bearings with severe impingement and titanium metallosis

The most common cause of long-term failure of total hip arthroplasty is osteolysis and aseptic loosening secondary to wear debris. Combinations of hard materials such as ceramic-on-ceramic generate smaller volumes of particulate wear debris than traditional combinations such as metal-on-polyethylene. We describe 2 cases where osteolysis arose in hips with third-generation alumina ceramic-on-ceramic couplings. Periarticular tissue in both cases contained titanium wear debris due to impingement of the neck of the titanium femoral component against the rim of the titanium shell and ceramic debris from edge loading wear (stripe wear) of the ceramic. It is not clear whether the titanium debris, the ceramic debris, or both caused the osteolysis. These cases illustrate that the risk of osteolysis persists, even with third-generation alumina ceramics.

The results of a proximally-coated cementless femoral component in total hip replacement: a five- to 12-year follow-up

This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading. A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12). The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur. This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading.

Alumina-on-alumina hip arthroplasty in patients younger than 30 years old

THA in patients younger than 30 years old presents challenges: the initial technical challenge relates to the initial disease that often causes deformities making reconstruction difficult, while the long-term challenge is wear and subsequent osteolysis and component loosening. Ceramic-on-ceramic prostheses may represent a valuable option to reduce wear. We retrospectively studied 101 patients (132 hips) with ceramic-on-ceramic prostheses implanted from 1977 to 2004. As a result of the long span of time, different implant designs and modes of fixation were used. The average age of the patients was 23.4+/-5 years (range, 13-30 years), and the main indication for THA was femoral head necrosis. The minimum followup was 1 year (mean, 6.9 years; range, 1-26.5 years). We documented 17 revisions (13%) for aseptic loosening. Twelve were for isolated acetabular loosening, two for isolated femoral loosening, and three for loosening of both components. Survivorship was 82.1% at 10 years and 72.4% at 15 years. Inferior survivorship was observed for THA performed after secondary arthritis related to slipped capital epiphysis or trauma. Limited osteolysis was observed in one hip. The main limiting factor in this series was the fixation of the acetabular component. However, improvements in the design and in the mode of fixation of this component should enhance long-term results.

LEVEL OF EVIDENCE

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

Resurfacing for Perthes disease: an alternative to standard hip arthroplasty

Metal-on-metal total hip resurfacing is an alternative to conventional total hip arthroplasty with several reports describing the benefits of this procedure in young patients. We retrospectively compared the clinical (including range-of-motion and leg length restoration) and radiographic outcome of resurfacing in young patients with Legg-Calvé-Perthes to those of patients of a similar age treated with a standard total hip arthroplasty. Eighteen patients (19 hip resurfacings) who had a mean age of 33 years (range, 18-34 years) were followed for a minimum of 26 months (mean, 51 months; range, 26-72 months). We used an anterolateral approach in four hips and a posterior approach with a trochanteric advancement in 15 hips. Eighteen of the 19 hips had Harris hip scores greater than 80 points at final followup. All patients improved range of motion while avoiding any clinically apparent impingement. Leg length was gained in 16 hips where preoperative measurements were available. The short-term results of hip resurfacing for the treatment of Perthes disease compare similarly to those found in the literature for standard total hip arthroplasty in young patients. The trochanteric advancement technique described may aid in treating the deformed femoral anatomy.

Engineering aspect of alumina on alumina hip prosthesis

Alumina on the alumina sliding system in a total hip replacement is recognized as a breakthrough in orthopaedic surgery. Advantages and problems with this material are explained and discussed in the light of 36 years of clinical application. Laboratory data as well as clinical ones are summarized.

A review of ceramic bearing materials in total joint arthroplasty

Bearings made of ceramics have ultra-low wear properties that make them suitable for total hip arthroplasty (THA) and total knee arthroplasty (TKA). When compared to cobalt chrome (CoCr)-on-polyethylene (PE) articulations, ceramics offer drastic reductions in bearing wear rates. Lower wear rates result in fewer wear particles produced by the articulating surfaces. In theory, this should reduce the risk of periprosthetic osteolysis and premature implant loosening, thereby contributing to the longevity of total joints. In addition to ceramics, other alternative bearing couples, such as highly cross-linked PE (XLPE) and metal-on-metal also offer less wear than CoCr-on-PE articulations in total joint arthroplasty. Alumina and zirconia ceramics are familiar to orthopaedic surgeons since both materials have been used in total joints for several decades. While not new in Europe, alumina-on-alumina ceramic total hips have only recently become available for widespread use in the United States from various orthopaedic implant manufacturers. As the search for the ideal total joint bearing material continues, composite materials of existing ceramics, metal-on-ceramic articulations, and new ceramic technologies will offer more choices to the arthroplasty surgeon. The objective of this paper is to present an overview of material properties, clinical applications, evolution, and limitations of ceramic materials that are of interest to the arthroplasty surgeon.

High long-term loosening rate of conical screw cups

BACKGROUND

Acetabular screw cups seem to give high primary stability. We analyzed the migration and loosening behavior of a first-generation screw cup in a longterm follow-up.

PATIENTS AND METHODS

We examined 92 uncemented titanium alloy conical screw cups prospectively. Implant migration was assessed with a digital high-precision method (EBRA) with an accuracy of 1.0 mm.

RESULTS

After mean 11 (0.5-18) years, 87 patients were available for examination and 5 patients had died. 32 implants had been revised and 7 cases showed radiographic evidence of loosening. The 10-year survival rate was 71%. Migration of more than 1 mm occurred in 53 hips. Implant survival was strongly associated with an annual migration of greater than 0.2 mm.

INTERPRETATION

The long-term behavior of this cup is not satisfactory. In spite of extraordinarily high primary implant stability, secondary osseointegration of this cup often fails. The annual migration rate represents a valid parameter for prediction of implant survival.

Use of an alumina-on-alumina bearing system in total hip arthroplasty for osteonecrosis of the hip

BACKGROUND

The results of total hip arthroplasty in patients with osteonecrosis of the femoral head are not always optimal. The use of alumina-on-alumina interfaces in young and active patients may decrease wear and lower the rate of aseptic loosening of the implant and appears to be an attractive alternative to the use of conventional cobalt-chromium-on-polyethylene bearings. The purpose of this study was to evaluate the safety and efficacy of the alumina-on-alumina bearing in patients with osteonecrosis and to compare this group of patients to a group of similarly treated patients with osteoarthritis and a group of patients who received conventional cobalt-chromium-on-polyethylene bearings.

METHODS

Patients were selected from a United States Investigational Device Exemption multicenter prospective randomized clinical study that was initiated in 1996. Seventy patients with osteonecrosis of the femoral head (seventy-nine hips) received a cementless alumina-on-alumina bearing system and were directly matched to seventy-six patients with osteoarthritis of the hip (seventy-nine hips) who were managed with the same implant. Both groups were compared with twenty-five patients (twenty-six hips) with osteonecrosis and twenty-five patients (twenty-six hips) with osteoarthritis who were managed with a cementless cobalt-chromium-on-polyethylene bearing system. All patients received a cementless hydroxyapatite-coated femoral stem and were followed both clinically and radiographically.

RESULTS

The clinical outcomes for alumina-on-alumina bearings were similar for both osteonecrotic and osteoarthritic hips. The seven-year survival probability was 95.5% for the osteonecrotic hips and 89.4% for the osteoarthritic hips in the alumina-on-alumina bearing group and 92.3% for the osteonecrotic hips and 92.9% for the osteoarthritic hips in the cobalt-chromium-on-polyethylene bearing group. At the time of the most recent follow-up, the mean Harris hip score was 96 points for both the osteonecrotic and the osteoarthritic hips in the alumina-on-alumina group and 96 points for the osteonecrotic hips and 97 points for the osteoarthritic hips in the cobalt-chromium-on-polyethylene bearing group.

CONCLUSIONS

The results of the use of alumina-on-alumina and cobalt-chromium-on-polyethylene bearings in cementless standard total hip implants in patients with osteonecrosis and osteoarthritis were comparable. The low revision rate for the alumina-on-alumina bearing is encouraging and offers a promising option for younger, more active patients who have this challenging disease.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Patient selection and surgical technique for surface arthroplasty of the hip

Factors such as patient selection, surgical technique, and durable fixation of the components are critical in surface arthroplasty of the hip. The Surface Arthroplasty Risk Index helps determine the risk of failure, with an index score </=3 having a 97% survivorship at 4 years. Because surface arthroplasty of the hip is conservative in nature and has the goal to closely reproduce the normal anatomy of the proximal femur, surgeons performing this procedure need to take into consideration the underlying pathology that led to the degenerative changes. Consequently, choice of surgical approach and positioning of the implants may have a greater impact on implant survivorship and patient function than in standard hip replacement. This article presents case illustrations of different hip pathologies treated by surface arthroplasty of the hip.